- 根目录:
- drivers
- staging
- iio
- adc
- mxs-lradc.c
/*
* Freescale i.MX28 LRADC driver
*
* Copyright (c) 2012 DENX Software Engineering, GmbH.
* Marek Vasut <marex@denx.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/sysfs.h>
#include <linux/list.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/stmp_device.h>
#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/input.h>
#include <linux/clk.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#define DRIVER_NAME "mxs-lradc"
#define LRADC_MAX_DELAY_CHANS 4
#define LRADC_MAX_MAPPED_CHANS 8
#define LRADC_MAX_TOTAL_CHANS 16
#define LRADC_DELAY_TIMER_HZ 2000
/*
* Make this runtime configurable if necessary. Currently, if the buffered mode
* is enabled, the LRADC takes LRADC_DELAY_TIMER_LOOP samples of data before
* triggering IRQ. The sampling happens every (LRADC_DELAY_TIMER_PER / 2000)
* seconds. The result is that the samples arrive every 500mS.
*/
#define LRADC_DELAY_TIMER_PER 200
#define LRADC_DELAY_TIMER_LOOP 5
/*
* Once the pen touches the touchscreen, the touchscreen switches from
* IRQ-driven mode to polling mode to prevent interrupt storm. The polling
* is realized by worker thread, which is called every 20 or so milliseconds.
* This gives the touchscreen enough fluence and does not strain the system
* too much.
*/
#define LRADC_TS_SAMPLE_DELAY_MS 5
/*
* The LRADC reads the following amount of samples from each touchscreen
* channel and the driver then computes avarage of these.
*/
#define LRADC_TS_SAMPLE_AMOUNT 4
enum mxs_lradc_id {
IMX23_LRADC,
IMX28_LRADC,
};
static const char * const mx23_lradc_irq_names[] = {
"mxs-lradc-touchscreen",
"mxs-lradc-channel0",
"mxs-lradc-channel1",
"mxs-lradc-channel2",
"mxs-lradc-channel3",
"mxs-lradc-channel4",
"mxs-lradc-channel5",
"mxs-lradc-channel6",
"mxs-lradc-channel7",
};
static const char * const mx28_lradc_irq_names[] = {
"mxs-lradc-touchscreen",
"mxs-lradc-thresh0",
"mxs-lradc-thresh1",
"mxs-lradc-channel0",
"mxs-lradc-channel1",
"mxs-lradc-channel2",
"mxs-lradc-channel3",
"mxs-lradc-channel4",
"mxs-lradc-channel5",
"mxs-lradc-channel6",
"mxs-lradc-channel7",
"mxs-lradc-button0",
"mxs-lradc-button1",
};
struct mxs_lradc_of_config {
const int irq_count;
const char * const *irq_name;
const uint32_t *vref_mv;
};
#define VREF_MV_BASE 1850
static const uint32_t mx23_vref_mv[LRADC_MAX_TOTAL_CHANS] = {
VREF_MV_BASE, /* CH0 */
VREF_MV_BASE, /* CH1 */
VREF_MV_BASE, /* CH2 */
VREF_MV_BASE, /* CH3 */
VREF_MV_BASE, /* CH4 */
VREF_MV_BASE, /* CH5 */
VREF_MV_BASE * 2, /* CH6 VDDIO */
VREF_MV_BASE * 4, /* CH7 VBATT */
VREF_MV_BASE, /* CH8 Temp sense 0 */
VREF_MV_BASE, /* CH9 Temp sense 1 */
VREF_MV_BASE, /* CH10 */
VREF_MV_BASE, /* CH11 */
VREF_MV_BASE, /* CH12 USB_DP */
VREF_MV_BASE, /* CH13 USB_DN */
VREF_MV_BASE, /* CH14 VBG */
VREF_MV_BASE * 4, /* CH15 VDD5V */
};
static const uint32_t mx28_vref_mv[LRADC_MAX_TOTAL_CHANS] = {
VREF_MV_BASE, /* CH0 */
VREF_MV_BASE, /* CH1 */
VREF_MV_BASE, /* CH2 */
VREF_MV_BASE, /* CH3 */
VREF_MV_BASE, /* CH4 */
VREF_MV_BASE, /* CH5 */
VREF_MV_BASE, /* CH6 */
VREF_MV_BASE * 4, /* CH7 VBATT */
VREF_MV_BASE, /* CH8 Temp sense 0 */
VREF_MV_BASE, /* CH9 Temp sense 1 */
VREF_MV_BASE * 2, /* CH10 VDDIO */
VREF_MV_BASE, /* CH11 VTH */
VREF_MV_BASE * 2, /* CH12 VDDA */
VREF_MV_BASE, /* CH13 VDDD */
VREF_MV_BASE, /* CH14 VBG */
VREF_MV_BASE * 4, /* CH15 VDD5V */
};
static const struct mxs_lradc_of_config mxs_lradc_of_config[] = {
[IMX23_LRADC] = {
.irq_count = ARRAY_SIZE(mx23_lradc_irq_names),
.irq_name = mx23_lradc_irq_names,
.vref_mv = mx23_vref_mv,
},
[IMX28_LRADC] = {
.irq_count = ARRAY_SIZE(mx28_lradc_irq_names),
.irq_name = mx28_lradc_irq_names,
.vref_mv = mx28_vref_mv,
},
};
enum mxs_lradc_ts {
MXS_LRADC_TOUCHSCREEN_NONE = 0,
MXS_LRADC_TOUCHSCREEN_4WIRE,
MXS_LRADC_TOUCHSCREEN_5WIRE,
};
/*
* Touchscreen handling
*/
enum lradc_ts_plate {
LRADC_TOUCH = 0,
LRADC_SAMPLE_X,
LRADC_SAMPLE_Y,
LRADC_SAMPLE_PRESSURE,
LRADC_SAMPLE_VALID,
};
enum mxs_lradc_divbytwo {
MXS_LRADC_DIV_DISABLED = 0,
MXS_LRADC_DIV_ENABLED,
};
struct mxs_lradc_scale {
unsigned int integer;
unsigned int nano;
};
struct mxs_lradc {
struct device *dev;
void __iomem *base;
int irq[13];
struct clk *clk;
uint32_t *buffer;
struct iio_trigger *trig;
struct mutex lock;
struct completion completion;
const uint32_t *vref_mv;
struct mxs_lradc_scale scale_avail[LRADC_MAX_TOTAL_CHANS][2];
unsigned long is_divided;
/*
* When the touchscreen is enabled, we give it two private virtual
* channels: #6 and #7. This means that only 6 virtual channels (instead
* of 8) will be available for buffered capture.
*/
#define TOUCHSCREEN_VCHANNEL1 7
#define TOUCHSCREEN_VCHANNEL2 6
#define BUFFER_VCHANS_LIMITED 0x3f
#define BUFFER_VCHANS_ALL 0xff
u8 buffer_vchans;
/*
* Furthermore, certain LRADC channels are shared between touchscreen
* and/or touch-buttons and generic LRADC block. Therefore when using
* either of these, these channels are not available for the regular
* sampling. The shared channels are as follows:
*
* CH0 -- Touch button #0
* CH1 -- Touch button #1
* CH2 -- Touch screen XPUL
* CH3 -- Touch screen YPLL
* CH4 -- Touch screen XNUL
* CH5 -- Touch screen YNLR
* CH6 -- Touch screen WIPER (5-wire only)
*
* The bitfields below represents which parts of the LRADC block are
* switched into special mode of operation. These channels can not
* be sampled as regular LRADC channels. The driver will refuse any
* attempt to sample these channels.
*/
#define CHAN_MASK_TOUCHBUTTON (BIT(1) | BIT(0))
#define CHAN_MASK_TOUCHSCREEN_4WIRE (0xf << 2)
#define CHAN_MASK_TOUCHSCREEN_5WIRE (0x1f << 2)
enum mxs_lradc_ts use_touchscreen;
bool use_touchbutton;
struct input_dev *ts_input;
enum mxs_lradc_id soc;
enum lradc_ts_plate cur_plate; /* statemachine */
bool ts_valid;
unsigned ts_x_pos;
unsigned ts_y_pos;
unsigned ts_pressure;
/* handle touchscreen's physical behaviour */
/* samples per coordinate */
unsigned over_sample_cnt;
/* time clocks between samples */
unsigned over_sample_delay;
/* time in clocks to wait after the plates where switched */
unsigned settling_delay;
};
#define LRADC_CTRL0 0x00
# define LRADC_CTRL0_MX28_TOUCH_DETECT_ENABLE BIT(23)
# define LRADC_CTRL0_MX28_TOUCH_SCREEN_TYPE BIT(22)
# define LRADC_CTRL0_MX28_YNNSW /* YM */ BIT(21)
# define LRADC_CTRL0_MX28_YPNSW /* YP */ BIT(20)
# define LRADC_CTRL0_MX28_YPPSW /* YP */ BIT(19)
# define LRADC_CTRL0_MX28_XNNSW /* XM */ BIT(18)
# define LRADC_CTRL0_MX28_XNPSW /* XM */ BIT(17)
# define LRADC_CTRL0_MX28_XPPSW /* XP */ BIT(16)
# define LRADC_CTRL0_MX23_TOUCH_DETECT_ENABLE BIT(20)
# define LRADC_CTRL0_MX23_YM BIT(19)
# define LRADC_CTRL0_MX23_XM BIT(18)
# define LRADC_CTRL0_MX23_YP BIT(17)
# define LRADC_CTRL0_MX23_XP BIT(16)
# define LRADC_CTRL0_MX28_PLATE_MASK \
(LRADC_CTRL0_MX28_TOUCH_DETECT_ENABLE | \
LRADC_CTRL0_MX28_YNNSW | LRADC_CTRL0_MX28_YPNSW | \
LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_XNNSW | \
LRADC_CTRL0_MX28_XNPSW | LRADC_CTRL0_MX28_XPPSW)
# define LRADC_CTRL0_MX23_PLATE_MASK \
(LRADC_CTRL0_MX23_TOUCH_DETECT_ENABLE | \
LRADC_CTRL0_MX23_YM | LRADC_CTRL0_MX23_XM | \
LRADC_CTRL0_MX23_YP | LRADC_CTRL0_MX23_XP)
#define LRADC_CTRL1 0x10
#define LRADC_CTRL1_TOUCH_DETECT_IRQ_EN BIT(24)
#define LRADC_CTRL1_LRADC_IRQ_EN(n) (1 << ((n) + 16))
#define LRADC_CTRL1_MX28_LRADC_IRQ_EN_MASK (0x1fff << 16)
#define LRADC_CTRL1_MX23_LRADC_IRQ_EN_MASK (0x01ff << 16)
#define LRADC_CTRL1_LRADC_IRQ_EN_OFFSET 16
#define LRADC_CTRL1_TOUCH_DETECT_IRQ BIT(8)
#define LRADC_CTRL1_LRADC_IRQ(n) (1 << (n))
#define LRADC_CTRL1_MX28_LRADC_IRQ_MASK 0x1fff
#define LRADC_CTRL1_MX23_LRADC_IRQ_MASK 0x01ff
#define LRADC_CTRL1_LRADC_IRQ_OFFSET 0
#define LRADC_CTRL2 0x20
#define LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET 24
#define LRADC_CTRL2_TEMPSENSE_PWD BIT(15)
#define LRADC_STATUS 0x40
#define LRADC_STATUS_TOUCH_DETECT_RAW BIT(0)
#define LRADC_CH(n) (0x50 + (0x10 * (n)))
#define LRADC_CH_ACCUMULATE BIT(29)
#define LRADC_CH_NUM_SAMPLES_MASK (0x1f << 24)
#define LRADC_CH_NUM_SAMPLES_OFFSET 24
#define LRADC_CH_NUM_SAMPLES(x) \
((x) << LRADC_CH_NUM_SAMPLES_OFFSET)
#define LRADC_CH_VALUE_MASK 0x3ffff
#define LRADC_CH_VALUE_OFFSET 0
#define LRADC_DELAY(n) (0xd0 + (0x10 * (n)))
#define LRADC_DELAY_TRIGGER_LRADCS_MASK (0xff << 24)
#define LRADC_DELAY_TRIGGER_LRADCS_OFFSET 24
#define LRADC_DELAY_TRIGGER(x) \
(((x) << LRADC_DELAY_TRIGGER_LRADCS_OFFSET) & \
LRADC_DELAY_TRIGGER_LRADCS_MASK)
#define LRADC_DELAY_KICK (1 << 20)
#define LRADC_DELAY_TRIGGER_DELAYS_MASK (0xf << 16)
#define LRADC_DELAY_TRIGGER_DELAYS_OFFSET 16
#define LRADC_DELAY_TRIGGER_DELAYS(x) \
(((x) << LRADC_DELAY_TRIGGER_DELAYS_OFFSET) & \
LRADC_DELAY_TRIGGER_DELAYS_MASK)
#define LRADC_DELAY_LOOP_COUNT_MASK (0x1f << 11)
#define LRADC_DELAY_LOOP_COUNT_OFFSET 11
#define LRADC_DELAY_LOOP(x) \
(((x) << LRADC_DELAY_LOOP_COUNT_OFFSET) & \
LRADC_DELAY_LOOP_COUNT_MASK)
#define LRADC_DELAY_DELAY_MASK 0x7ff
#define LRADC_DELAY_DELAY_OFFSET 0
#define LRADC_DELAY_DELAY(x) \
(((x) << LRADC_DELAY_DELAY_OFFSET) & \
LRADC_DELAY_DELAY_MASK)
#define LRADC_CTRL4 0x140
#define LRADC_CTRL4_LRADCSELECT_MASK(n) (0xf << ((n) * 4))
#define LRADC_CTRL4_LRADCSELECT_OFFSET(n) ((n) * 4)
#define LRADC_CTRL4_LRADCSELECT(n, x) \
(((x) << LRADC_CTRL4_LRADCSELECT_OFFSET(n)) & \
LRADC_CTRL4_LRADCSELECT_MASK(n))
#define LRADC_RESOLUTION 12
#define LRADC_SINGLE_SAMPLE_MASK ((1 << LRADC_RESOLUTION) - 1)
static void mxs_lradc_reg_set(struct mxs_lradc *lradc, u32 val, u32 reg)
{
writel(val, lradc->base + reg + STMP_OFFSET_REG_SET);
}
static void mxs_lradc_reg_clear(struct mxs_lradc *lradc, u32 val, u32 reg)
{
writel(val, lradc->base + reg + STMP_OFFSET_REG_CLR);
}
static void mxs_lradc_reg_wrt(struct mxs_lradc *lradc, u32 val, u32 reg)
{
writel(val, lradc->base + reg);
}
static u32 mxs_lradc_plate_mask(struct mxs_lradc *lradc)
{
if (lradc->soc == IMX23_LRADC)
return LRADC_CTRL0_MX23_PLATE_MASK;
return LRADC_CTRL0_MX28_PLATE_MASK;
}
static u32 mxs_lradc_irq_en_mask(struct mxs_lradc *lradc)
{
if (lradc->soc == IMX23_LRADC)
return LRADC_CTRL1_MX23_LRADC_IRQ_EN_MASK;
return LRADC_CTRL1_MX28_LRADC_IRQ_EN_MASK;
}
static u32 mxs_lradc_irq_mask(struct mxs_lradc *lradc)
{
if (lradc->soc == IMX23_LRADC)
return LRADC_CTRL1_MX23_LRADC_IRQ_MASK;
return LRADC_CTRL1_MX28_LRADC_IRQ_MASK;
}
static u32 mxs_lradc_touch_detect_bit(struct mxs_lradc *lradc)
{
if (lradc->soc == IMX23_LRADC)
return LRADC_CTRL0_MX23_TOUCH_DETECT_ENABLE;
return LRADC_CTRL0_MX28_TOUCH_DETECT_ENABLE;
}
static u32 mxs_lradc_drive_x_plate(struct mxs_lradc *lradc)
{
if (lradc->soc == IMX23_LRADC)
return LRADC_CTRL0_MX23_XP | LRADC_CTRL0_MX23_XM;
return LRADC_CTRL0_MX28_XPPSW | LRADC_CTRL0_MX28_XNNSW;
}
static u32 mxs_lradc_drive_y_plate(struct mxs_lradc *lradc)
{
if (lradc->soc == IMX23_LRADC)
return LRADC_CTRL0_MX23_YP | LRADC_CTRL0_MX23_YM;
return LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_YNNSW;
}
static u32 mxs_lradc_drive_pressure(struct mxs_lradc *lradc)
{
if (lradc->soc == IMX23_LRADC)
return LRADC_CTRL0_MX23_YP | LRADC_CTRL0_MX23_XM;
return LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_XNNSW;
}
static bool mxs_lradc_check_touch_event(struct mxs_lradc *lradc)
{
return !!(readl(lradc->base + LRADC_STATUS) &
LRADC_STATUS_TOUCH_DETECT_RAW);
}
static void mxs_lradc_map_channel(struct mxs_lradc *lradc, unsigned vch,
unsigned ch)
{
mxs_lradc_reg_clear(lradc, LRADC_CTRL4_LRADCSELECT_MASK(vch),
LRADC_CTRL4);
mxs_lradc_reg_set(lradc, LRADC_CTRL4_LRADCSELECT(vch, ch), LRADC_CTRL4);
}
static void mxs_lradc_setup_ts_channel(struct mxs_lradc *lradc, unsigned ch)
{
/*
* prepare for oversampling conversion
*
* from the datasheet:
* "The ACCUMULATE bit in the appropriate channel register
* HW_LRADC_CHn must be set to 1 if NUM_SAMPLES is greater then 0;
* otherwise, the IRQs will not fire."
*/
mxs_lradc_reg_wrt(lradc, LRADC_CH_ACCUMULATE |
LRADC_CH_NUM_SAMPLES(lradc->over_sample_cnt - 1),
LRADC_CH(ch));
/* from the datasheet:
* "Software must clear this register in preparation for a
* multi-cycle accumulation.
*/
mxs_lradc_reg_clear(lradc, LRADC_CH_VALUE_MASK, LRADC_CH(ch));
/*
* prepare the delay/loop unit according to the oversampling count
*
* from the datasheet:
* "The DELAY fields in HW_LRADC_DELAY0, HW_LRADC_DELAY1,
* HW_LRADC_DELAY2, and HW_LRADC_DELAY3 must be non-zero; otherwise,
* the LRADC will not trigger the delay group."
*/
mxs_lradc_reg_wrt(lradc, LRADC_DELAY_TRIGGER(1 << ch) |
LRADC_DELAY_TRIGGER_DELAYS(0) |
LRADC_DELAY_LOOP(lradc->over_sample_cnt - 1) |
LRADC_DELAY_DELAY(lradc->over_sample_delay - 1),
LRADC_DELAY(3));
mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ(ch), LRADC_CTRL1);
/*
* after changing the touchscreen plates setting
* the signals need some initial time to settle. Start the
* SoC's delay unit and start the conversion later
* and automatically.
*/
mxs_lradc_reg_wrt(lradc,
LRADC_DELAY_TRIGGER(0) | /* don't trigger ADC */
LRADC_DELAY_TRIGGER_DELAYS(BIT(3)) | /* trigger DELAY unit#3 */
LRADC_DELAY_KICK |
LRADC_DELAY_DELAY(lradc->settling_delay),
LRADC_DELAY(2));
}
/*
* Pressure detection is special:
* We want to do both required measurements for the pressure detection in
* one turn. Use the hardware features to chain both conversions and let the
* hardware report one interrupt if both conversions are done
*/
static void mxs_lradc_setup_ts_pressure(struct mxs_lradc *lradc, unsigned ch1,
unsigned ch2)
{
u32 reg;
/*
* prepare for oversampling conversion
*
* from the datasheet:
* "The ACCUMULATE bit in the appropriate channel register
* HW_LRADC_CHn must be set to 1 if NUM_SAMPLES is greater then 0;
* otherwise, the IRQs will not fire."
*/
reg = LRADC_CH_ACCUMULATE |
LRADC_CH_NUM_SAMPLES(lradc->over_sample_cnt - 1);
mxs_lradc_reg_wrt(lradc, reg, LRADC_CH(ch1));
mxs_lradc_reg_wrt(lradc, reg, LRADC_CH(ch2));
/* from the datasheet:
* "Software must clear this register in preparation for a
* multi-cycle accumulation.
*/
mxs_lradc_reg_clear(lradc, LRADC_CH_VALUE_MASK, LRADC_CH(ch1));
mxs_lradc_reg_clear(lradc, LRADC_CH_VALUE_MASK, LRADC_CH(ch2));
/* prepare the delay/loop unit according to the oversampling count */
mxs_lradc_reg_wrt(lradc, LRADC_DELAY_TRIGGER(1 << ch1) |
LRADC_DELAY_TRIGGER(1 << ch2) | /* start both channels */
LRADC_DELAY_TRIGGER_DELAYS(0) |
LRADC_DELAY_LOOP(lradc->over_sample_cnt - 1) |
LRADC_DELAY_DELAY(lradc->over_sample_delay - 1),
LRADC_DELAY(3));
mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ(ch2), LRADC_CTRL1);
/*
* after changing the touchscreen plates setting
* the signals need some initial time to settle. Start the
* SoC's delay unit and start the conversion later
* and automatically.
*/
mxs_lradc_reg_wrt(lradc,
LRADC_DELAY_TRIGGER(0) | /* don't trigger ADC */
LRADC_DELAY_TRIGGER_DELAYS(BIT(3)) | /* trigger DELAY unit#3 */
LRADC_DELAY_KICK |
LRADC_DELAY_DELAY(lradc->settling_delay), LRADC_DELAY(2));
}
static unsigned mxs_lradc_read_raw_channel(struct mxs_lradc *lradc,
unsigned channel)
{
u32 reg;
unsigned num_samples, val;
reg = readl(lradc->base + LRADC_CH(channel));
if (reg & LRADC_CH_ACCUMULATE)
num_samples = lradc->over_sample_cnt;
else
num_samples = 1;
val = (reg & LRADC_CH_VALUE_MASK) >> LRADC_CH_VALUE_OFFSET;
return val / num_samples;
}
static unsigned mxs_lradc_read_ts_pressure(struct mxs_lradc *lradc,
unsigned ch1, unsigned ch2)
{
u32 reg, mask;
unsigned pressure, m1, m2;
mask = LRADC_CTRL1_LRADC_IRQ(ch1) | LRADC_CTRL1_LRADC_IRQ(ch2);
reg = readl(lradc->base + LRADC_CTRL1) & mask;
while (reg != mask) {
reg = readl(lradc->base + LRADC_CTRL1) & mask;
dev_dbg(lradc->dev, "One channel is still busy: %X\n", reg);
}
m1 = mxs_lradc_read_raw_channel(lradc, ch1);
m2 = mxs_lradc_read_raw_channel(lradc, ch2);
if (m2 == 0) {
dev_warn(lradc->dev, "Cannot calculate pressure\n");
return 1 << (LRADC_RESOLUTION - 1);
}
/* simply scale the value from 0 ... max ADC resolution */
pressure = m1;
pressure *= (1 << LRADC_RESOLUTION);
pressure /= m2;
dev_dbg(lradc->dev, "Pressure = %u\n", pressure);
return pressure;
}
#define TS_CH_XP 2
#define TS_CH_YP 3
#define TS_CH_XM 4
#define TS_CH_YM 5
/*
* YP(open)--+-------------+
* | |--+
* | | |
* YM(-)--+-------------+ |
* +--------------+
* | |
* XP(weak+) XM(open)
*
* "weak+" means 200k Ohm VDDIO
* (-) means GND
*/
static void mxs_lradc_setup_touch_detection(struct mxs_lradc *lradc)
{
/*
* In order to detect a touch event the 'touch detect enable' bit
* enables:
* - a weak pullup to the X+ connector
* - a strong ground at the Y- connector
*/
mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
mxs_lradc_reg_set(lradc, mxs_lradc_touch_detect_bit(lradc),
LRADC_CTRL0);
}
/*
* YP(meas)--+-------------+
* | |--+
* | | |
* YM(open)--+-------------+ |
* +--------------+
* | |
* XP(+) XM(-)
*
* (+) means here 1.85 V
* (-) means here GND
*/
static void mxs_lradc_prepare_x_pos(struct mxs_lradc *lradc)
{
mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
mxs_lradc_reg_set(lradc, mxs_lradc_drive_x_plate(lradc), LRADC_CTRL0);
lradc->cur_plate = LRADC_SAMPLE_X;
mxs_lradc_map_channel(lradc, TOUCHSCREEN_VCHANNEL1, TS_CH_YP);
mxs_lradc_setup_ts_channel(lradc, TOUCHSCREEN_VCHANNEL1);
}
/*
* YP(+)--+-------------+
* | |--+
* | | |
* YM(-)--+-------------+ |
* +--------------+
* | |
* XP(open) XM(meas)
*
* (+) means here 1.85 V
* (-) means here GND
*/
static void mxs_lradc_prepare_y_pos(struct mxs_lradc *lradc)
{
mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
mxs_lradc_reg_set(lradc, mxs_lradc_drive_y_plate(lradc), LRADC_CTRL0);
lradc->cur_plate = LRADC_SAMPLE_Y;
mxs_lradc_map_channel(lradc, TOUCHSCREEN_VCHANNEL1, TS_CH_XM);
mxs_lradc_setup_ts_channel(lradc, TOUCHSCREEN_VCHANNEL1);
}
/*
* YP(+)--+-------------+
* | |--+
* | | |
* YM(meas)--+-------------+ |
* +--------------+
* | |
* XP(meas) XM(-)
*
* (+) means here 1.85 V
* (-) means here GND
*/
static void mxs_lradc_prepare_pressure(struct mxs_lradc *lradc)
{
mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
mxs_lradc_reg_set(lradc, mxs_lradc_drive_pressure(lradc), LRADC_CTRL0);
lradc->cur_plate = LRADC_SAMPLE_PRESSURE;
mxs_lradc_map_channel(lradc, TOUCHSCREEN_VCHANNEL1, TS_CH_YM);
mxs_lradc_map_channel(lradc, TOUCHSCREEN_VCHANNEL2, TS_CH_XP);
mxs_lradc_setup_ts_pressure(lradc, TOUCHSCREEN_VCHANNEL2,
TOUCHSCREEN_VCHANNEL1);
}
static void mxs_lradc_enable_touch_detection(struct mxs_lradc *lradc)
{
mxs_lradc_setup_touch_detection(lradc);
lradc->cur_plate = LRADC_TOUCH;
mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ |
LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
mxs_lradc_reg_set(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
}
static void mxs_lradc_start_touch_event(struct mxs_lradc *lradc)
{
mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
LRADC_CTRL1);
mxs_lradc_reg_set(lradc,
LRADC_CTRL1_LRADC_IRQ_EN(TOUCHSCREEN_VCHANNEL1), LRADC_CTRL1);
/*
* start with the Y-pos, because it uses nearly the same plate
* settings like the touch detection
*/
mxs_lradc_prepare_y_pos(lradc);
}
static void mxs_lradc_report_ts_event(struct mxs_lradc *lradc)
{
input_report_abs(lradc->ts_input, ABS_X, lradc->ts_x_pos);
input_report_abs(lradc->ts_input, ABS_Y, lradc->ts_y_pos);
input_report_abs(lradc->ts_input, ABS_PRESSURE, lradc->ts_pressure);
input_report_key(lradc->ts_input, BTN_TOUCH, 1);
input_sync(lradc->ts_input);
}
static void mxs_lradc_complete_touch_event(struct mxs_lradc *lradc)
{
mxs_lradc_setup_touch_detection(lradc);
lradc->cur_plate = LRADC_SAMPLE_VALID;
/*
* start a dummy conversion to burn time to settle the signals
* note: we are not interested in the conversion's value
*/
mxs_lradc_reg_wrt(lradc, 0, LRADC_CH(TOUCHSCREEN_VCHANNEL1));
mxs_lradc_reg_clear(lradc,
LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL1) |
LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL2), LRADC_CTRL1);
mxs_lradc_reg_wrt(lradc,
LRADC_DELAY_TRIGGER(1 << TOUCHSCREEN_VCHANNEL1) |
LRADC_DELAY_KICK | LRADC_DELAY_DELAY(10), /* waste 5 ms */
LRADC_DELAY(2));
}
/*
* in order to avoid false measurements, report only samples where
* the surface is still touched after the position measurement
*/
static void mxs_lradc_finish_touch_event(struct mxs_lradc *lradc, bool valid)
{
/* if it is still touched, report the sample */
if (valid && mxs_lradc_check_touch_event(lradc)) {
lradc->ts_valid = true;
mxs_lradc_report_ts_event(lradc);
}
/* if it is even still touched, continue with the next measurement */
if (mxs_lradc_check_touch_event(lradc)) {
mxs_lradc_prepare_y_pos(lradc);
return;
}
if (lradc->ts_valid) {
/* signal the release */
lradc->ts_valid = false;
input_report_key(lradc->ts_input, BTN_TOUCH, 0);
input_sync(lradc->ts_input);
}
/* if it is released, wait for the next touch via IRQ */
lradc->cur_plate = LRADC_TOUCH;
mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(2));
mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(3));
mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ |
LRADC_CTRL1_LRADC_IRQ_EN(TOUCHSCREEN_VCHANNEL1) |
LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL1), LRADC_CTRL1);
mxs_lradc_reg_set(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
}
/* touchscreen's state machine */
static void mxs_lradc_handle_touch(struct mxs_lradc *lradc)
{
switch (lradc->cur_plate) {
case LRADC_TOUCH:
if (mxs_lradc_check_touch_event(lradc))
mxs_lradc_start_touch_event(lradc);
mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ,
LRADC_CTRL1);
return;
case LRADC_SAMPLE_Y:
lradc->ts_y_pos = mxs_lradc_read_raw_channel(lradc,
TOUCHSCREEN_VCHANNEL1);
mxs_lradc_prepare_x_pos(lradc);
return;
case LRADC_SAMPLE_X:
lradc->ts_x_pos = mxs_lradc_read_raw_channel(lradc,
TOUCHSCREEN_VCHANNEL1);
mxs_lradc_prepare_pressure(lradc);
return;
case LRADC_SAMPLE_PRESSURE:
lradc->ts_pressure = mxs_lradc_read_ts_pressure(lradc,
TOUCHSCREEN_VCHANNEL2,
TOUCHSCREEN_VCHANNEL1);
mxs_lradc_complete_touch_event(lradc);
return;
case LRADC_SAMPLE_VALID:
mxs_lradc_finish_touch_event(lradc, 1);
break;
}
}
/*
* Raw I/O operations
*/
static int mxs_lradc_read_single(struct iio_dev *iio_dev, int chan, int *val)
{
struct mxs_lradc *lradc = iio_priv(iio_dev);
int ret;
/*
* See if there is no buffered operation in progess. If there is, simply
* bail out. This can be improved to support both buffered and raw IO at
* the same time, yet the code becomes horribly complicated. Therefore I
* applied KISS principle here.
*/
ret = mutex_trylock(&lradc->lock);
if (!ret)
return -EBUSY;
reinit_completion(&lradc->completion);
/*
* No buffered operation in progress, map the channel and trigger it.
* Virtual channel 0 is always used here as the others are always not
* used if doing raw sampling.
*/
if (lradc->soc == IMX28_LRADC)
mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ_EN(0),
LRADC_CTRL1);
mxs_lradc_reg_clear(lradc, 0x1, LRADC_CTRL0);
/* Enable / disable the divider per requirement */
if (test_bit(chan, &lradc->is_divided))
mxs_lradc_reg_set(lradc, 1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET,
LRADC_CTRL2);
else
mxs_lradc_reg_clear(lradc,
1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET, LRADC_CTRL2);
/* Clean the slot's previous content, then set new one. */
mxs_lradc_reg_clear(lradc, LRADC_CTRL4_LRADCSELECT_MASK(0),
LRADC_CTRL4);
mxs_lradc_reg_set(lradc, chan, LRADC_CTRL4);
mxs_lradc_reg_wrt(lradc, 0, LRADC_CH(0));
/* Enable the IRQ and start sampling the channel. */
mxs_lradc_reg_set(lradc, LRADC_CTRL1_LRADC_IRQ_EN(0), LRADC_CTRL1);
mxs_lradc_reg_set(lradc, BIT(0), LRADC_CTRL0);
/* Wait for completion on the channel, 1 second max. */
ret = wait_for_completion_killable_timeout(&lradc->completion, HZ);
if (!ret)
ret = -ETIMEDOUT;
if (ret < 0)
goto err;
/* Read the data. */
*val = readl(lradc->base + LRADC_CH(0)) & LRADC_CH_VALUE_MASK;
ret = IIO_VAL_INT;
err:
mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ_EN(0), LRADC_CTRL1);
mutex_unlock(&lradc->lock);
return ret;
}
static int mxs_lradc_read_temp(struct iio_dev *iio_dev, int *val)
{
int ret, min, max;
ret = mxs_lradc_read_single(iio_dev, 8, &min);
if (ret != IIO_VAL_INT)
return ret;
ret = mxs_lradc_read_single(iio_dev, 9, &max);
if (ret != IIO_VAL_INT)
return ret;
*val = max - min;
return IIO_VAL_INT;
}
static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
const struct iio_chan_spec *chan,
int *val, int *val2, long m)
{
struct mxs_lradc *lradc = iio_priv(iio_dev);
switch (m) {
case IIO_CHAN_INFO_RAW:
if (chan->type == IIO_TEMP)
return mxs_lradc_read_temp(iio_dev, val);
return mxs_lradc_read_single(iio_dev, chan->channel, val);
case IIO_CHAN_INFO_SCALE:
if (chan->type == IIO_TEMP) {
/* From the datasheet, we have to multiply by 1.012 and
* divide by 4
*/
*val = 0;
*val2 = 253000;
return IIO_VAL_INT_PLUS_MICRO;
}
*val = lradc->vref_mv[chan->channel];
*val2 = chan->scan_type.realbits -
test_bit(chan->channel, &lradc->is_divided);
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_OFFSET:
if (chan->type == IIO_TEMP) {
/* The calculated value from the ADC is in Kelvin, we
* want Celsius for hwmon so the offset is
* -272.15 * scale
*/
*val = -1075;
*val2 = 691699;
return IIO_VAL_INT_PLUS_MICRO;
}
return -EINVAL;
default:
break;
}
return -EINVAL;
}
static int mxs_lradc_write_raw(struct iio_dev *iio_dev,
const struct iio_chan_spec *chan,
int val, int val2, long m)
{
struct mxs_lradc *lradc = iio_priv(iio_dev);
struct mxs_lradc_scale *scale_avail =
lradc->scale_avail[chan->channel];
int ret;
ret = mutex_trylock(&lradc->lock);
if (!ret)
return -EBUSY;
switch (m) {
case IIO_CHAN_INFO_SCALE:
ret = -EINVAL;
if (val == scale_avail[MXS_LRADC_DIV_DISABLED].integer &&
val2 == scale_avail[MXS_LRADC_DIV_DISABLED].nano) {
/* divider by two disabled */
clear_bit(chan->channel, &lradc->is_divided);
ret = 0;
} else if (val == scale_avail[MXS_LRADC_DIV_ENABLED].integer &&
val2 == scale_avail[MXS_LRADC_DIV_ENABLED].nano) {
/* divider by two enabled */
set_bit(chan->channel, &lradc->is_divided);
ret = 0;
}
break;
default:
ret = -EINVAL;
break;
}
mutex_unlock(&lradc->lock);
return ret;
}
static int mxs_lradc_write_raw_get_fmt(struct iio_dev *iio_dev,
const struct iio_chan_spec *chan,
long m)
{
return IIO_VAL_INT_PLUS_NANO;
}
static ssize_t mxs_lradc_show_scale_available_ch(struct device *dev,
struct device_attribute *attr,
char *buf,
int ch)
{
struct iio_dev *iio = dev_to_iio_dev(dev);
struct mxs_lradc *lradc = iio_priv(iio);
int i, len = 0;
for (i = 0; i < ARRAY_SIZE(lradc->scale_avail[ch]); i++)
len += sprintf(buf + len, "%u.%09u ",
lradc->scale_avail[ch][i].integer,
lradc->scale_avail[ch][i].nano);
len += sprintf(buf + len, "\n");
return len;
}
static ssize_t mxs_lradc_show_scale_available(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev_attr *iio_attr = to_iio_dev_attr(attr);
return mxs_lradc_show_scale_available_ch(dev, attr, buf,
iio_attr->address);
}
#define SHOW_SCALE_AVAILABLE_ATTR(ch) \
static IIO_DEVICE_ATTR(in_voltage##ch##_scale_available, S_IRUGO, \
mxs_lradc_show_scale_available, NULL, ch)
SHOW_SCALE_AVAILABLE_ATTR(0);
SHOW_SCALE_AVAILABLE_ATTR(1);
SHOW_SCALE_AVAILABLE_ATTR(2);
SHOW_SCALE_AVAILABLE_ATTR(3);
SHOW_SCALE_AVAILABLE_ATTR(4);
SHOW_SCALE_AVAILABLE_ATTR(5);
SHOW_SCALE_AVAILABLE_ATTR(6);
SHOW_SCALE_AVAILABLE_ATTR(7);
SHOW_SCALE_AVAILABLE_ATTR(10);
SHOW_SCALE_AVAILABLE_ATTR(11);
SHOW_SCALE_AVAILABLE_ATTR(12);
SHOW_SCALE_AVAILABLE_ATTR(13);
SHOW_SCALE_AVAILABLE_ATTR(14);
SHOW_SCALE_AVAILABLE_ATTR(15);
static struct attribute *mxs_lradc_attributes[] = {
&iio_dev_attr_in_voltage0_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage1_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage2_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage3_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage4_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage5_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage6_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage7_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage10_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage11_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage12_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage13_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage14_scale_available.dev_attr.attr,
&iio_dev_attr_in_voltage15_scale_available.dev_attr.attr,
NULL
};
static const struct attribute_group mxs_lradc_attribute_group = {
.attrs = mxs_lradc_attributes,
};
static const struct iio_info mxs_lradc_iio_info = {
.driver_module = THIS_MODULE,
.read_raw = mxs_lradc_read_raw,
.write_raw = mxs_lradc_write_raw,
.write_raw_get_fmt = mxs_lradc_write_raw_get_fmt,
.attrs = &mxs_lradc_attribute_group,
};
static int mxs_lradc_ts_open(struct input_dev *dev)
{
struct mxs_lradc *lradc = input_get_drvdata(dev);
/* Enable the touch-detect circuitry. */
mxs_lradc_enable_touch_detection(lradc);
return 0;
}
static void mxs_lradc_disable_ts(struct mxs_lradc *lradc)
{
/* stop all interrupts from firing */
mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN |
LRADC_CTRL1_LRADC_IRQ_EN(TOUCHSCREEN_VCHANNEL1) |
LRADC_CTRL1_LRADC_IRQ_EN(TOUCHSCREEN_VCHANNEL2), LRADC_CTRL1);
/* Power-down touchscreen touch-detect circuitry. */
mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
}
static void mxs_lradc_ts_close(struct input_dev *dev)
{
struct mxs_lradc *lradc = input_get_drvdata(dev);
mxs_lradc_disable_ts(lradc);
}
static int mxs_lradc_ts_register(struct mxs_lradc *lradc)
{
struct input_dev *input;
struct device *dev = lradc->dev;
int ret;
if (!lradc->use_touchscreen)
return 0;
input = input_allocate_device();
if (!input)
return -ENOMEM;
input->name = DRIVER_NAME;
input->id.bustype = BUS_HOST;
input->dev.parent = dev;
input->open = mxs_lradc_ts_open;
input->close = mxs_lradc_ts_close;
__set_bit(EV_ABS, input->evbit);
__set_bit(EV_KEY, input->evbit);
__set_bit(BTN_TOUCH, input->keybit);
input_set_abs_params(input, ABS_X, 0, LRADC_SINGLE_SAMPLE_MASK, 0, 0);
input_set_abs_params(input, ABS_Y, 0, LRADC_SINGLE_SAMPLE_MASK, 0, 0);
input_set_abs_params(input, ABS_PRESSURE, 0, LRADC_SINGLE_SAMPLE_MASK,
0, 0);
lradc->ts_input = input;
input_set_drvdata(input, lradc);
ret = input_register_device(input);
if (ret)
input_free_device(lradc->ts_input);
return ret;
}
static void mxs_lradc_ts_unregister(struct mxs_lradc *lradc)
{
if (!lradc->use_touchscreen)
return;
mxs_lradc_disable_ts(lradc);
input_unregister_device(lradc->ts_input);
}
/*
* IRQ Handling
*/
static irqreturn_t mxs_lradc_handle_irq(int irq, void *data)
{
struct iio_dev *iio = data;
struct mxs_lradc *lradc = iio_priv(iio);
unsigned long reg = readl(lradc->base + LRADC_CTRL1);
uint32_t clr_irq = mxs_lradc_irq_mask(lradc);
const uint32_t ts_irq_mask =
LRADC_CTRL1_TOUCH_DETECT_IRQ |
LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL1) |
LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL2);
if (!(reg & mxs_lradc_irq_mask(lradc)))
return IRQ_NONE;
if (lradc->use_touchscreen && (reg & ts_irq_mask)) {
mxs_lradc_handle_touch(lradc);
/* Make sure we don't clear the next conversion's interrupt. */
clr_irq &= ~(LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL1) |
LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL2));
}
if (iio_buffer_enabled(iio)) {
if (reg & lradc->buffer_vchans)
iio_trigger_poll(iio->trig);
} else if (reg & LRADC_CTRL1_LRADC_IRQ(0)) {
complete(&lradc->completion);
}
mxs_lradc_reg_clear(lradc, reg & clr_irq, LRADC_CTRL1);
return IRQ_HANDLED;
}
/*
* Trigger handling
*/
static irqreturn_t mxs_lradc_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *iio = pf->indio_dev;
struct mxs_lradc *lradc = iio_priv(iio);
const uint32_t chan_value = LRADC_CH_ACCUMULATE |
((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
unsigned int i, j = 0;
for_each_set_bit(i, iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS) {
lradc->buffer[j] = readl(lradc->base + LRADC_CH(j));
mxs_lradc_reg_wrt(lradc, chan_value, LRADC_CH(j));
lradc->buffer[j] &= LRADC_CH_VALUE_MASK;
lradc->buffer[j] /= LRADC_DELAY_TIMER_LOOP;
j++;
}
iio_push_to_buffers_with_timestamp(iio, lradc->buffer, pf->timestamp);
iio_trigger_notify_done(iio->trig);
return IRQ_HANDLED;
}
static int mxs_lradc_configure_trigger(struct iio_trigger *trig, bool state)
{
struct iio_dev *iio = iio_trigger_get_drvdata(trig);
struct mxs_lradc *lradc = iio_priv(iio);
const uint32_t st = state ? STMP_OFFSET_REG_SET : STMP_OFFSET_REG_CLR;
mxs_lradc_reg_wrt(lradc, LRADC_DELAY_KICK, LRADC_DELAY(0) + st);
return 0;
}
static const struct iio_trigger_ops mxs_lradc_trigger_ops = {
.owner = THIS_MODULE,
.set_trigger_state = &mxs_lradc_configure_trigger,
};
static int mxs_lradc_trigger_init(struct iio_dev *iio)
{
int ret;
struct iio_trigger *trig;
struct mxs_lradc *lradc = iio_priv(iio);
trig = iio_trigger_alloc("%s-dev%i", iio->name, iio->id);
if (trig == NULL)
return -ENOMEM;
trig->dev.parent = lradc->dev;
iio_trigger_set_drvdata(trig, iio);
trig->ops = &mxs_lradc_trigger_ops;
ret = iio_trigger_register(trig);
if (ret) {
iio_trigger_free(trig);
return ret;
}
lradc->trig = trig;
return 0;
}
static void mxs_lradc_trigger_remove(struct iio_dev *iio)
{
struct mxs_lradc *lradc = iio_priv(iio);
iio_trigger_unregister(lradc->trig);
iio_trigger_free(lradc->trig);
}
static int mxs_lradc_buffer_preenable(struct iio_dev *iio)
{
struct mxs_lradc *lradc = iio_priv(iio);
int ret = 0, chan, ofs = 0;
unsigned long enable = 0;
uint32_t ctrl4_set = 0;
uint32_t ctrl4_clr = 0;
uint32_t ctrl1_irq = 0;
const uint32_t chan_value = LRADC_CH_ACCUMULATE |
((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
const int len = bitmap_weight(iio->active_scan_mask,
LRADC_MAX_TOTAL_CHANS);
if (!len)
return -EINVAL;
/*
* Lock the driver so raw access can not be done during buffered
* operation. This simplifies the code a lot.
*/
ret = mutex_trylock(&lradc->lock);
if (!ret)
return -EBUSY;
lradc->buffer = kmalloc_array(len, sizeof(*lradc->buffer), GFP_KERNEL);
if (!lradc->buffer) {
ret = -ENOMEM;
goto err_mem;
}
if (lradc->soc == IMX28_LRADC)
mxs_lradc_reg_clear(lradc,
lradc->buffer_vchans << LRADC_CTRL1_LRADC_IRQ_EN_OFFSET,
LRADC_CTRL1);
mxs_lradc_reg_clear(lradc, lradc->buffer_vchans, LRADC_CTRL0);
for_each_set_bit(chan, iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS) {
ctrl4_set |= chan << LRADC_CTRL4_LRADCSELECT_OFFSET(ofs);
ctrl4_clr |= LRADC_CTRL4_LRADCSELECT_MASK(ofs);
ctrl1_irq |= LRADC_CTRL1_LRADC_IRQ_EN(ofs);
mxs_lradc_reg_wrt(lradc, chan_value, LRADC_CH(ofs));
bitmap_set(&enable, ofs, 1);
ofs++;
}
mxs_lradc_reg_clear(lradc, LRADC_DELAY_TRIGGER_LRADCS_MASK |
LRADC_DELAY_KICK, LRADC_DELAY(0));
mxs_lradc_reg_clear(lradc, ctrl4_clr, LRADC_CTRL4);
mxs_lradc_reg_set(lradc, ctrl4_set, LRADC_CTRL4);
mxs_lradc_reg_set(lradc, ctrl1_irq, LRADC_CTRL1);
mxs_lradc_reg_set(lradc, enable << LRADC_DELAY_TRIGGER_LRADCS_OFFSET,
LRADC_DELAY(0));
return 0;
err_mem:
mutex_unlock(&lradc->lock);
return ret;
}
static int mxs_lradc_buffer_postdisable(struct iio_dev *iio)
{
struct mxs_lradc *lradc = iio_priv(iio);
mxs_lradc_reg_clear(lradc, LRADC_DELAY_TRIGGER_LRADCS_MASK |
LRADC_DELAY_KICK, LRADC_DELAY(0));
mxs_lradc_reg_clear(lradc, lradc->buffer_vchans, LRADC_CTRL0);
if (lradc->soc == IMX28_LRADC)
mxs_lradc_reg_clear(lradc,
lradc->buffer_vchans << LRADC_CTRL1_LRADC_IRQ_EN_OFFSET,
LRADC_CTRL1);
kfree(lradc->buffer);
mutex_unlock(&lradc->lock);
return 0;
}
static bool mxs_lradc_validate_scan_mask(struct iio_dev *iio,
const unsigned long *mask)
{
struct mxs_lradc *lradc = iio_priv(iio);
const int map_chans = bitmap_weight(mask, LRADC_MAX_TOTAL_CHANS);
int rsvd_chans = 0;
unsigned long rsvd_mask = 0;
if (lradc->use_touchbutton)
rsvd_mask |= CHAN_MASK_TOUCHBUTTON;
if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_4WIRE)
rsvd_mask |= CHAN_MASK_TOUCHSCREEN_4WIRE;
if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE)
rsvd_mask |= CHAN_MASK_TOUCHSCREEN_5WIRE;
if (lradc->use_touchbutton)
rsvd_chans++;
if (lradc->use_touchscreen)
rsvd_chans += 2;
/* Test for attempts to map channels with special mode of operation. */
if (bitmap_intersects(mask, &rsvd_mask, LRADC_MAX_TOTAL_CHANS))
return false;
/* Test for attempts to map more channels then available slots. */
if (map_chans + rsvd_chans > LRADC_MAX_MAPPED_CHANS)
return false;
return true;
}
static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
.preenable = &mxs_lradc_buffer_preenable,
.postenable = &iio_triggered_buffer_postenable,
.predisable = &iio_triggered_buffer_predisable,
.postdisable = &mxs_lradc_buffer_postdisable,
.validate_scan_mask = &mxs_lradc_validate_scan_mask,
};
/*
* Driver initialization
*/
#define MXS_ADC_CHAN(idx, chan_type) { \
.type = (chan_type), \
.indexed = 1, \
.scan_index = (idx), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
BIT(IIO_CHAN_INFO_SCALE), \
.channel = (idx), \
.address = (idx), \
.scan_type = { \
.sign = 'u', \
.realbits = LRADC_RESOLUTION, \
.storagebits = 32, \
}, \
}
static const struct iio_chan_spec mxs_lradc_chan_spec[] = {
MXS_ADC_CHAN(0, IIO_VOLTAGE),
MXS_ADC_CHAN(1, IIO_VOLTAGE),
MXS_ADC_CHAN(2, IIO_VOLTAGE),
MXS_ADC_CHAN(3, IIO_VOLTAGE),
MXS_ADC_CHAN(4, IIO_VOLTAGE),
MXS_ADC_CHAN(5, IIO_VOLTAGE),
MXS_ADC_CHAN(6, IIO_VOLTAGE),
MXS_ADC_CHAN(7, IIO_VOLTAGE), /* VBATT */
/* Combined Temperature sensors */
{
.type = IIO_TEMP,
.indexed = 1,
.scan_index = 8,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_OFFSET) |
BIT(IIO_CHAN_INFO_SCALE),
.channel = 8,
.scan_type = {.sign = 'u', .realbits = 18, .storagebits = 32,},
},
/* Hidden channel to keep indexes */
{
.type = IIO_TEMP,
.indexed = 1,
.scan_index = -1,
.channel = 9,
},
MXS_ADC_CHAN(10, IIO_VOLTAGE), /* VDDIO */
MXS_ADC_CHAN(11, IIO_VOLTAGE), /* VTH */
MXS_ADC_CHAN(12, IIO_VOLTAGE), /* VDDA */
MXS_ADC_CHAN(13, IIO_VOLTAGE), /* VDDD */
MXS_ADC_CHAN(14, IIO_VOLTAGE), /* VBG */
MXS_ADC_CHAN(15, IIO_VOLTAGE), /* VDD5V */
};
static int mxs_lradc_hw_init(struct mxs_lradc *lradc)
{
/* The ADC always uses DELAY CHANNEL 0. */
const uint32_t adc_cfg =
(1 << (LRADC_DELAY_TRIGGER_DELAYS_OFFSET + 0)) |
(LRADC_DELAY_TIMER_PER << LRADC_DELAY_DELAY_OFFSET);
int ret = stmp_reset_block(lradc->base);
if (ret)
return ret;
/* Configure DELAY CHANNEL 0 for generic ADC sampling. */
mxs_lradc_reg_wrt(lradc, adc_cfg, LRADC_DELAY(0));
/* Disable remaining DELAY CHANNELs */
mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(1));
mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(2));
mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(3));
/* Configure the touchscreen type */
if (lradc->soc == IMX28_LRADC) {
mxs_lradc_reg_clear(lradc, LRADC_CTRL0_MX28_TOUCH_SCREEN_TYPE,
LRADC_CTRL0);
if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE)
mxs_lradc_reg_set(lradc, LRADC_CTRL0_MX28_TOUCH_SCREEN_TYPE,
LRADC_CTRL0);
}
/* Start internal temperature sensing. */
mxs_lradc_reg_wrt(lradc, 0, LRADC_CTRL2);
return 0;
}
static void mxs_lradc_hw_stop(struct mxs_lradc *lradc)
{
int i;
mxs_lradc_reg_clear(lradc, mxs_lradc_irq_en_mask(lradc), LRADC_CTRL1);
for (i = 0; i < LRADC_MAX_DELAY_CHANS; i++)
mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(i));
}
static const struct of_device_id mxs_lradc_dt_ids[] = {
{ .compatible = "fsl,imx23-lradc", .data = (void *)IMX23_LRADC, },
{ .compatible = "fsl,imx28-lradc", .data = (void *)IMX28_LRADC, },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids);
static int mxs_lradc_probe_touchscreen(struct mxs_lradc *lradc,
struct device_node *lradc_node)
{
int ret;
u32 ts_wires = 0, adapt;
ret = of_property_read_u32(lradc_node, "fsl,lradc-touchscreen-wires",
&ts_wires);
if (ret)
return -ENODEV; /* touchscreen feature disabled */
switch (ts_wires) {
case 4:
lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_4WIRE;
break;
case 5:
if (lradc->soc == IMX28_LRADC) {
lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_5WIRE;
break;
}
/* fall through an error message for i.MX23 */
default:
dev_err(lradc->dev,
"Unsupported number of touchscreen wires (%d)\n",
ts_wires);
return -EINVAL;
}
if (of_property_read_u32(lradc_node, "fsl,ave-ctrl", &adapt)) {
lradc->over_sample_cnt = 4;
} else {
if (adapt < 1 || adapt > 32) {
dev_err(lradc->dev, "Invalid sample count (%u)\n",
adapt);
return -EINVAL;
}
lradc->over_sample_cnt = adapt;
}
if (of_property_read_u32(lradc_node, "fsl,ave-delay", &adapt)) {
lradc->over_sample_delay = 2;
} else {
if (adapt < 2 || adapt > LRADC_DELAY_DELAY_MASK + 1) {
dev_err(lradc->dev, "Invalid sample delay (%u)\n",
adapt);
return -EINVAL;
}
lradc->over_sample_delay = adapt;
}
if (of_property_read_u32(lradc_node, "fsl,settling", &adapt)) {
lradc->settling_delay = 10;
} else {
if (adapt < 1 || adapt > LRADC_DELAY_DELAY_MASK) {
dev_err(lradc->dev, "Invalid settling delay (%u)\n",
adapt);
return -EINVAL;
}
lradc->settling_delay = adapt;
}
return 0;
}
static int mxs_lradc_probe(struct platform_device *pdev)
{
const struct of_device_id *of_id =
of_match_device(mxs_lradc_dt_ids, &pdev->dev);
const struct mxs_lradc_of_config *of_cfg =
&mxs_lradc_of_config[(enum mxs_lradc_id)of_id->data];
struct device *dev = &pdev->dev;
struct device_node *node = dev->of_node;
struct mxs_lradc *lradc;
struct iio_dev *iio;
struct resource *iores;
int ret = 0, touch_ret;
int i, s;
uint64_t scale_uv;
/* Allocate the IIO device. */
iio = devm_iio_device_alloc(dev, sizeof(*lradc));
if (!iio) {
dev_err(dev, "Failed to allocate IIO device\n");
return -ENOMEM;
}
lradc = iio_priv(iio);
lradc->soc = (enum mxs_lradc_id)of_id->data;
/* Grab the memory area */
iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
lradc->dev = &pdev->dev;
lradc->base = devm_ioremap_resource(dev, iores);
if (IS_ERR(lradc->base))
return PTR_ERR(lradc->base);
lradc->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(lradc->clk)) {
dev_err(dev, "Failed to get the delay unit clock\n");
return PTR_ERR(lradc->clk);
}
ret = clk_prepare_enable(lradc->clk);
if (ret != 0) {
dev_err(dev, "Failed to enable the delay unit clock\n");
return ret;
}
touch_ret = mxs_lradc_probe_touchscreen(lradc, node);
if (touch_ret == 0)
lradc->buffer_vchans = BUFFER_VCHANS_LIMITED;
else
lradc->buffer_vchans = BUFFER_VCHANS_ALL;
/* Grab all IRQ sources */
for (i = 0; i < of_cfg->irq_count; i++) {
lradc->irq[i] = platform_get_irq(pdev, i);
if (lradc->irq[i] < 0) {
ret = lradc->irq[i];
goto err_clk;
}
ret = devm_request_irq(dev, lradc->irq[i],
mxs_lradc_handle_irq, 0,
of_cfg->irq_name[i], iio);
if (ret)
goto err_clk;
}
lradc->vref_mv = of_cfg->vref_mv;
platform_set_drvdata(pdev, iio);
init_completion(&lradc->completion);
mutex_init(&lradc->lock);
iio->name = pdev->name;
iio->dev.parent = &pdev->dev;
iio->info = &mxs_lradc_iio_info;
iio->modes = INDIO_DIRECT_MODE;
iio->channels = mxs_lradc_chan_spec;
iio->num_channels = ARRAY_SIZE(mxs_lradc_chan_spec);
iio->masklength = LRADC_MAX_TOTAL_CHANS;
ret = iio_triggered_buffer_setup(iio, &iio_pollfunc_store_time,
&mxs_lradc_trigger_handler,
&mxs_lradc_buffer_ops);
if (ret)
goto err_clk;
ret = mxs_lradc_trigger_init(iio);
if (ret)
goto err_trig;
/* Populate available ADC input ranges */
for (i = 0; i < LRADC_MAX_TOTAL_CHANS; i++) {
for (s = 0; s < ARRAY_SIZE(lradc->scale_avail[i]); s++) {
/*
* [s=0] = optional divider by two disabled (default)
* [s=1] = optional divider by two enabled
*
* The scale is calculated by doing:
* Vref >> (realbits - s)
* which multiplies by two on the second component
* of the array.
*/
scale_uv = ((u64)lradc->vref_mv[i] * 100000000) >>
(LRADC_RESOLUTION - s);
lradc->scale_avail[i][s].nano =
do_div(scale_uv, 100000000) * 10;
lradc->scale_avail[i][s].integer = scale_uv;
}
}
/* Configure the hardware. */
ret = mxs_lradc_hw_init(lradc);
if (ret)
goto err_dev;
/* Register the touchscreen input device. */
if (touch_ret == 0) {
ret = mxs_lradc_ts_register(lradc);
if (ret)
goto err_ts_register;
}
/* Register IIO device. */
ret = iio_device_register(iio);
if (ret) {
dev_err(dev, "Failed to register IIO device\n");
goto err_ts;
}
return 0;
err_ts:
mxs_lradc_ts_unregister(lradc);
err_ts_register:
mxs_lradc_hw_stop(lradc);
err_dev:
mxs_lradc_trigger_remove(iio);
err_trig:
iio_triggered_buffer_cleanup(iio);
err_clk:
clk_disable_unprepare(lradc->clk);
return ret;
}
static int mxs_lradc_remove(struct platform_device *pdev)
{
struct iio_dev *iio = platform_get_drvdata(pdev);
struct mxs_lradc *lradc = iio_priv(iio);
iio_device_unregister(iio);
mxs_lradc_ts_unregister(lradc);
mxs_lradc_hw_stop(lradc);
mxs_lradc_trigger_remove(iio);
iio_triggered_buffer_cleanup(iio);
clk_disable_unprepare(lradc->clk);
return 0;
}
static struct platform_driver mxs_lradc_driver = {
.driver = {
.name = DRIVER_NAME,
.of_match_table = mxs_lradc_dt_ids,
},
.probe = mxs_lradc_probe,
.remove = mxs_lradc_remove,
};
module_platform_driver(mxs_lradc_driver);
MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
MODULE_DESCRIPTION("Freescale i.MX28 LRADC driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRIVER_NAME);