- 根目录:
- drivers
- pwm
- pwm-renesas-tpu.c
/*
* R-Mobile TPU PWM driver
*
* Copyright (C) 2012 Renesas Solutions Corp.
*
* 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
*
* 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/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/pwm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#define TPU_CHANNEL_MAX 4
#define TPU_TSTR 0x00 /* Timer start register (shared) */
#define TPU_TCRn 0x00 /* Timer control register */
#define TPU_TCR_CCLR_NONE (0 << 5)
#define TPU_TCR_CCLR_TGRA (1 << 5)
#define TPU_TCR_CCLR_TGRB (2 << 5)
#define TPU_TCR_CCLR_TGRC (5 << 5)
#define TPU_TCR_CCLR_TGRD (6 << 5)
#define TPU_TCR_CKEG_RISING (0 << 3)
#define TPU_TCR_CKEG_FALLING (1 << 3)
#define TPU_TCR_CKEG_BOTH (2 << 3)
#define TPU_TMDRn 0x04 /* Timer mode register */
#define TPU_TMDR_BFWT (1 << 6)
#define TPU_TMDR_BFB (1 << 5)
#define TPU_TMDR_BFA (1 << 4)
#define TPU_TMDR_MD_NORMAL (0 << 0)
#define TPU_TMDR_MD_PWM (2 << 0)
#define TPU_TIORn 0x08 /* Timer I/O control register */
#define TPU_TIOR_IOA_0 (0 << 0)
#define TPU_TIOR_IOA_0_CLR (1 << 0)
#define TPU_TIOR_IOA_0_SET (2 << 0)
#define TPU_TIOR_IOA_0_TOGGLE (3 << 0)
#define TPU_TIOR_IOA_1 (4 << 0)
#define TPU_TIOR_IOA_1_CLR (5 << 0)
#define TPU_TIOR_IOA_1_SET (6 << 0)
#define TPU_TIOR_IOA_1_TOGGLE (7 << 0)
#define TPU_TIERn 0x0c /* Timer interrupt enable register */
#define TPU_TSRn 0x10 /* Timer status register */
#define TPU_TCNTn 0x14 /* Timer counter */
#define TPU_TGRAn 0x18 /* Timer general register A */
#define TPU_TGRBn 0x1c /* Timer general register B */
#define TPU_TGRCn 0x20 /* Timer general register C */
#define TPU_TGRDn 0x24 /* Timer general register D */
#define TPU_CHANNEL_OFFSET 0x10
#define TPU_CHANNEL_SIZE 0x40
enum tpu_pin_state {
TPU_PIN_INACTIVE, /* Pin is driven inactive */
TPU_PIN_PWM, /* Pin is driven by PWM */
TPU_PIN_ACTIVE, /* Pin is driven active */
};
struct tpu_device;
struct tpu_pwm_device {
bool timer_on; /* Whether the timer is running */
struct tpu_device *tpu;
unsigned int channel; /* Channel number in the TPU */
enum pwm_polarity polarity;
unsigned int prescaler;
u16 period;
u16 duty;
};
struct tpu_device {
struct platform_device *pdev;
struct pwm_chip chip;
spinlock_t lock;
void __iomem *base;
struct clk *clk;
};
#define to_tpu_device(c) container_of(c, struct tpu_device, chip)
static void tpu_pwm_write(struct tpu_pwm_device *pwm, int reg_nr, u16 value)
{
void __iomem *base = pwm->tpu->base + TPU_CHANNEL_OFFSET
+ pwm->channel * TPU_CHANNEL_SIZE;
iowrite16(value, base + reg_nr);
}
static void tpu_pwm_set_pin(struct tpu_pwm_device *pwm,
enum tpu_pin_state state)
{
static const char * const states[] = { "inactive", "PWM", "active" };
dev_dbg(&pwm->tpu->pdev->dev, "%u: configuring pin as %s\n",
pwm->channel, states[state]);
switch (state) {
case TPU_PIN_INACTIVE:
tpu_pwm_write(pwm, TPU_TIORn,
pwm->polarity == PWM_POLARITY_INVERSED ?
TPU_TIOR_IOA_1 : TPU_TIOR_IOA_0);
break;
case TPU_PIN_PWM:
tpu_pwm_write(pwm, TPU_TIORn,
pwm->polarity == PWM_POLARITY_INVERSED ?
TPU_TIOR_IOA_0_SET : TPU_TIOR_IOA_1_CLR);
break;
case TPU_PIN_ACTIVE:
tpu_pwm_write(pwm, TPU_TIORn,
pwm->polarity == PWM_POLARITY_INVERSED ?
TPU_TIOR_IOA_0 : TPU_TIOR_IOA_1);
break;
}
}
static void tpu_pwm_start_stop(struct tpu_pwm_device *pwm, int start)
{
unsigned long flags;
u16 value;
spin_lock_irqsave(&pwm->tpu->lock, flags);
value = ioread16(pwm->tpu->base + TPU_TSTR);
if (start)
value |= 1 << pwm->channel;
else
value &= ~(1 << pwm->channel);
iowrite16(value, pwm->tpu->base + TPU_TSTR);
spin_unlock_irqrestore(&pwm->tpu->lock, flags);
}
static int tpu_pwm_timer_start(struct tpu_pwm_device *pwm)
{
int ret;
if (!pwm->timer_on) {
/* Wake up device and enable clock. */
pm_runtime_get_sync(&pwm->tpu->pdev->dev);
ret = clk_prepare_enable(pwm->tpu->clk);
if (ret) {
dev_err(&pwm->tpu->pdev->dev, "cannot enable clock\n");
return ret;
}
pwm->timer_on = true;
}
/*
* Make sure the channel is stopped, as we need to reconfigure it
* completely. First drive the pin to the inactive state to avoid
* glitches.
*/
tpu_pwm_set_pin(pwm, TPU_PIN_INACTIVE);
tpu_pwm_start_stop(pwm, false);
/*
* - Clear TCNT on TGRB match
* - Count on rising edge
* - Set prescaler
* - Output 0 until TGRA, output 1 until TGRB (active low polarity)
* - Output 1 until TGRA, output 0 until TGRB (active high polarity
* - PWM mode
*/
tpu_pwm_write(pwm, TPU_TCRn, TPU_TCR_CCLR_TGRB | TPU_TCR_CKEG_RISING |
pwm->prescaler);
tpu_pwm_write(pwm, TPU_TMDRn, TPU_TMDR_MD_PWM);
tpu_pwm_set_pin(pwm, TPU_PIN_PWM);
tpu_pwm_write(pwm, TPU_TGRAn, pwm->duty);
tpu_pwm_write(pwm, TPU_TGRBn, pwm->period);
dev_dbg(&pwm->tpu->pdev->dev, "%u: TGRA 0x%04x TGRB 0x%04x\n",
pwm->channel, pwm->duty, pwm->period);
/* Start the channel. */
tpu_pwm_start_stop(pwm, true);
return 0;
}
static void tpu_pwm_timer_stop(struct tpu_pwm_device *pwm)
{
if (!pwm->timer_on)
return;
/* Disable channel. */
tpu_pwm_start_stop(pwm, false);
/* Stop clock and mark device as idle. */
clk_disable_unprepare(pwm->tpu->clk);
pm_runtime_put(&pwm->tpu->pdev->dev);
pwm->timer_on = false;
}
/* -----------------------------------------------------------------------------
* PWM API
*/
static int tpu_pwm_request(struct pwm_chip *chip, struct pwm_device *_pwm)
{
struct tpu_device *tpu = to_tpu_device(chip);
struct tpu_pwm_device *pwm;
if (_pwm->hwpwm >= TPU_CHANNEL_MAX)
return -EINVAL;
pwm = kzalloc(sizeof(*pwm), GFP_KERNEL);
if (pwm == NULL)
return -ENOMEM;
pwm->tpu = tpu;
pwm->channel = _pwm->hwpwm;
pwm->polarity = PWM_POLARITY_NORMAL;
pwm->prescaler = 0;
pwm->period = 0;
pwm->duty = 0;
pwm->timer_on = false;
pwm_set_chip_data(_pwm, pwm);
return 0;
}
static void tpu_pwm_free(struct pwm_chip *chip, struct pwm_device *_pwm)
{
struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
tpu_pwm_timer_stop(pwm);
kfree(pwm);
}
static int tpu_pwm_config(struct pwm_chip *chip, struct pwm_device *_pwm,
int duty_ns, int period_ns)
{
static const unsigned int prescalers[] = { 1, 4, 16, 64 };
struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
struct tpu_device *tpu = to_tpu_device(chip);
unsigned int prescaler;
bool duty_only = false;
u32 clk_rate;
u32 period;
u32 duty;
int ret;
/*
* Pick a prescaler to avoid overflowing the counter.
* TODO: Pick the highest acceptable prescaler.
*/
clk_rate = clk_get_rate(tpu->clk);
for (prescaler = 0; prescaler < ARRAY_SIZE(prescalers); ++prescaler) {
period = clk_rate / prescalers[prescaler]
/ (NSEC_PER_SEC / period_ns);
if (period <= 0xffff)
break;
}
if (prescaler == ARRAY_SIZE(prescalers) || period == 0) {
dev_err(&tpu->pdev->dev, "clock rate mismatch\n");
return -ENOTSUPP;
}
if (duty_ns) {
duty = clk_rate / prescalers[prescaler]
/ (NSEC_PER_SEC / duty_ns);
if (duty > period)
return -EINVAL;
} else {
duty = 0;
}
dev_dbg(&tpu->pdev->dev,
"rate %u, prescaler %u, period %u, duty %u\n",
clk_rate, prescalers[prescaler], period, duty);
if (pwm->prescaler == prescaler && pwm->period == period)
duty_only = true;
pwm->prescaler = prescaler;
pwm->period = period;
pwm->duty = duty;
/* If the channel is disabled we're done. */
if (!pwm_is_enabled(_pwm))
return 0;
if (duty_only && pwm->timer_on) {
/*
* If only the duty cycle changed and the timer is already
* running, there's no need to reconfigure it completely, Just
* modify the duty cycle.
*/
tpu_pwm_write(pwm, TPU_TGRAn, pwm->duty);
dev_dbg(&tpu->pdev->dev, "%u: TGRA 0x%04x\n", pwm->channel,
pwm->duty);
} else {
/* Otherwise perform a full reconfiguration. */
ret = tpu_pwm_timer_start(pwm);
if (ret < 0)
return ret;
}
if (duty == 0 || duty == period) {
/*
* To avoid running the timer when not strictly required, handle
* 0% and 100% duty cycles as fixed levels and stop the timer.
*/
tpu_pwm_set_pin(pwm, duty ? TPU_PIN_ACTIVE : TPU_PIN_INACTIVE);
tpu_pwm_timer_stop(pwm);
}
return 0;
}
static int tpu_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *_pwm,
enum pwm_polarity polarity)
{
struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
pwm->polarity = polarity;
return 0;
}
static int tpu_pwm_enable(struct pwm_chip *chip, struct pwm_device *_pwm)
{
struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
int ret;
ret = tpu_pwm_timer_start(pwm);
if (ret < 0)
return ret;
/*
* To avoid running the timer when not strictly required, handle 0% and
* 100% duty cycles as fixed levels and stop the timer.
*/
if (pwm->duty == 0 || pwm->duty == pwm->period) {
tpu_pwm_set_pin(pwm, pwm->duty ?
TPU_PIN_ACTIVE : TPU_PIN_INACTIVE);
tpu_pwm_timer_stop(pwm);
}
return 0;
}
static void tpu_pwm_disable(struct pwm_chip *chip, struct pwm_device *_pwm)
{
struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
/* The timer must be running to modify the pin output configuration. */
tpu_pwm_timer_start(pwm);
tpu_pwm_set_pin(pwm, TPU_PIN_INACTIVE);
tpu_pwm_timer_stop(pwm);
}
static const struct pwm_ops tpu_pwm_ops = {
.request = tpu_pwm_request,
.free = tpu_pwm_free,
.config = tpu_pwm_config,
.set_polarity = tpu_pwm_set_polarity,
.enable = tpu_pwm_enable,
.disable = tpu_pwm_disable,
.owner = THIS_MODULE,
};
/* -----------------------------------------------------------------------------
* Probe and remove
*/
static int tpu_probe(struct platform_device *pdev)
{
struct tpu_device *tpu;
struct resource *res;
int ret;
tpu = devm_kzalloc(&pdev->dev, sizeof(*tpu), GFP_KERNEL);
if (tpu == NULL)
return -ENOMEM;
spin_lock_init(&tpu->lock);
tpu->pdev = pdev;
/* Map memory, get clock and pin control. */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
tpu->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(tpu->base))
return PTR_ERR(tpu->base);
tpu->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(tpu->clk)) {
dev_err(&pdev->dev, "cannot get clock\n");
return PTR_ERR(tpu->clk);
}
/* Initialize and register the device. */
platform_set_drvdata(pdev, tpu);
tpu->chip.dev = &pdev->dev;
tpu->chip.ops = &tpu_pwm_ops;
tpu->chip.of_xlate = of_pwm_xlate_with_flags;
tpu->chip.of_pwm_n_cells = 3;
tpu->chip.base = -1;
tpu->chip.npwm = TPU_CHANNEL_MAX;
ret = pwmchip_add(&tpu->chip);
if (ret < 0) {
dev_err(&pdev->dev, "failed to register PWM chip\n");
return ret;
}
dev_info(&pdev->dev, "TPU PWM %d registered\n", tpu->pdev->id);
pm_runtime_enable(&pdev->dev);
return 0;
}
static int tpu_remove(struct platform_device *pdev)
{
struct tpu_device *tpu = platform_get_drvdata(pdev);
int ret;
ret = pwmchip_remove(&tpu->chip);
if (ret)
return ret;
pm_runtime_disable(&pdev->dev);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id tpu_of_table[] = {
{ .compatible = "renesas,tpu-r8a73a4", },
{ .compatible = "renesas,tpu-r8a7740", },
{ .compatible = "renesas,tpu-r8a7790", },
{ .compatible = "renesas,tpu-sh7372", },
{ .compatible = "renesas,tpu", },
{ },
};
MODULE_DEVICE_TABLE(of, tpu_of_table);
#endif
static struct platform_driver tpu_driver = {
.probe = tpu_probe,
.remove = tpu_remove,
.driver = {
.name = "renesas-tpu-pwm",
.of_match_table = of_match_ptr(tpu_of_table),
}
};
module_platform_driver(tpu_driver);
MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
MODULE_DESCRIPTION("Renesas TPU PWM Driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:renesas-tpu-pwm");