/*
* Freescale MXS I2C bus driver
*
* Copyright (C) 2011-2012 Wolfram Sang, Pengutronix e.K.
*
* based on a (non-working) driver which was:
*
* Copyright (C) 2009-2010 Freescale Semiconductor, Inc. All Rights Reserved.
*
* 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.
*
*/
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/platform_device.h>
#include <linux/jiffies.h>
#include <linux/io.h>
#include <linux/pinctrl/consumer.h>
#include <linux/stmp_device.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_i2c.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#define DRIVER_NAME "mxs-i2c"
#define MXS_I2C_CTRL0 (0x00)
#define MXS_I2C_CTRL0_SET (0x04)
#define MXS_I2C_CTRL0_SFTRST 0x80000000
#define MXS_I2C_CTRL0_RUN 0x20000000
#define MXS_I2C_CTRL0_SEND_NAK_ON_LAST 0x02000000
#define MXS_I2C_CTRL0_RETAIN_CLOCK 0x00200000
#define MXS_I2C_CTRL0_POST_SEND_STOP 0x00100000
#define MXS_I2C_CTRL0_PRE_SEND_START 0x00080000
#define MXS_I2C_CTRL0_MASTER_MODE 0x00020000
#define MXS_I2C_CTRL0_DIRECTION 0x00010000
#define MXS_I2C_CTRL0_XFER_COUNT(v) ((v) & 0x0000FFFF)
#define MXS_I2C_TIMING0 (0x10)
#define MXS_I2C_TIMING1 (0x20)
#define MXS_I2C_TIMING2 (0x30)
#define MXS_I2C_CTRL1 (0x40)
#define MXS_I2C_CTRL1_SET (0x44)
#define MXS_I2C_CTRL1_CLR (0x48)
#define MXS_I2C_CTRL1_CLR_GOT_A_NAK 0x10000000
#define MXS_I2C_CTRL1_BUS_FREE_IRQ 0x80
#define MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ 0x40
#define MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ 0x20
#define MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ 0x10
#define MXS_I2C_CTRL1_EARLY_TERM_IRQ 0x08
#define MXS_I2C_CTRL1_MASTER_LOSS_IRQ 0x04
#define MXS_I2C_CTRL1_SLAVE_STOP_IRQ 0x02
#define MXS_I2C_CTRL1_SLAVE_IRQ 0x01
#define MXS_I2C_STAT (0x50)
#define MXS_I2C_STAT_BUS_BUSY 0x00000800
#define MXS_I2C_STAT_CLK_GEN_BUSY 0x00000400
#define MXS_I2C_DATA (0xa0)
#define MXS_I2C_DEBUG0 (0xb0)
#define MXS_I2C_DEBUG0_CLR (0xb8)
#define MXS_I2C_DEBUG0_DMAREQ 0x80000000
#define MXS_I2C_IRQ_MASK (MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ | \
MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ | \
MXS_I2C_CTRL1_EARLY_TERM_IRQ | \
MXS_I2C_CTRL1_MASTER_LOSS_IRQ | \
MXS_I2C_CTRL1_SLAVE_STOP_IRQ | \
MXS_I2C_CTRL1_SLAVE_IRQ)
#define MXS_CMD_I2C_SELECT (MXS_I2C_CTRL0_RETAIN_CLOCK | \
MXS_I2C_CTRL0_PRE_SEND_START | \
MXS_I2C_CTRL0_MASTER_MODE | \
MXS_I2C_CTRL0_DIRECTION | \
MXS_I2C_CTRL0_XFER_COUNT(1))
#define MXS_CMD_I2C_WRITE (MXS_I2C_CTRL0_PRE_SEND_START | \
MXS_I2C_CTRL0_MASTER_MODE | \
MXS_I2C_CTRL0_DIRECTION)
#define MXS_CMD_I2C_READ (MXS_I2C_CTRL0_SEND_NAK_ON_LAST | \
MXS_I2C_CTRL0_MASTER_MODE)
/**
* struct mxs_i2c_dev - per device, private MXS-I2C data
*
* @dev: driver model device node
* @regs: IO registers pointer
* @cmd_complete: completion object for transaction wait
* @cmd_err: error code for last transaction
* @adapter: i2c subsystem adapter node
*/
struct mxs_i2c_dev {
struct device *dev;
void __iomem *regs;
struct completion cmd_complete;
int cmd_err;
struct i2c_adapter adapter;
uint32_t timing0;
uint32_t timing1;
/* DMA support components */
struct dma_chan *dmach;
uint32_t pio_data[2];
uint32_t addr_data;
struct scatterlist sg_io[2];
bool dma_read;
};
static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
{
stmp_reset_block(i2c->regs);
/*
* Configure timing for the I2C block. The I2C TIMING2 register has to
* be programmed with this particular magic number. The rest is derived
* from the XTAL speed and requested I2C speed.
*
* For details, see i.MX233 [25.4.2 - 25.4.4] and i.MX28 [27.5.2 - 27.5.4].
*/
writel(i2c->timing0, i2c->regs + MXS_I2C_TIMING0);
writel(i2c->timing1, i2c->regs + MXS_I2C_TIMING1);
writel(0x00300030, i2c->regs + MXS_I2C_TIMING2);
writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
}
static void mxs_i2c_dma_finish(struct mxs_i2c_dev *i2c)
{
if (i2c->dma_read) {
dma_unmap_sg(i2c->dev, &i2c->sg_io[0], 1, DMA_TO_DEVICE);
dma_unmap_sg(i2c->dev, &i2c->sg_io[1], 1, DMA_FROM_DEVICE);
} else {
dma_unmap_sg(i2c->dev, i2c->sg_io, 2, DMA_TO_DEVICE);
}
}
static void mxs_i2c_dma_irq_callback(void *param)
{
struct mxs_i2c_dev *i2c = param;
complete(&i2c->cmd_complete);
mxs_i2c_dma_finish(i2c);
}
static int mxs_i2c_dma_setup_xfer(struct i2c_adapter *adap,
struct i2c_msg *msg, uint32_t flags)
{
struct dma_async_tx_descriptor *desc;
struct mxs_i2c_dev *i2c = i2c_get_adapdata(adap);
if (msg->flags & I2C_M_RD) {
i2c->dma_read = 1;
i2c->addr_data = (msg->addr << 1) | I2C_SMBUS_READ;
/*
* SELECT command.
*/
/* Queue the PIO register write transfer. */
i2c->pio_data[0] = MXS_CMD_I2C_SELECT;
desc = dmaengine_prep_slave_sg(i2c->dmach,
(struct scatterlist *)&i2c->pio_data[0],
1, DMA_TRANS_NONE, 0);
if (!desc) {
dev_err(i2c->dev,
"Failed to get PIO reg. write descriptor.\n");
goto select_init_pio_fail;
}
/* Queue the DMA data transfer. */
sg_init_one(&i2c->sg_io[0], &i2c->addr_data, 1);
dma_map_sg(i2c->dev, &i2c->sg_io[0], 1, DMA_TO_DEVICE);
desc = dmaengine_prep_slave_sg(i2c->dmach, &i2c->sg_io[0], 1,
DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
dev_err(i2c->dev,
"Failed to get DMA data write descriptor.\n");
goto select_init_dma_fail;
}
/*
* READ command.
*/
/* Queue the PIO register write transfer. */
i2c->pio_data[1] = flags | MXS_CMD_I2C_READ |
MXS_I2C_CTRL0_XFER_COUNT(msg->len);
desc = dmaengine_prep_slave_sg(i2c->dmach,
(struct scatterlist *)&i2c->pio_data[1],
1, DMA_TRANS_NONE, DMA_PREP_INTERRUPT);
if (!desc) {
dev_err(i2c->dev,
"Failed to get PIO reg. write descriptor.\n");
goto select_init_dma_fail;
}
/* Queue the DMA data transfer. */
sg_init_one(&i2c->sg_io[1], msg->buf, msg->len);
dma_map_sg(i2c->dev, &i2c->sg_io[1], 1, DMA_FROM_DEVICE);
desc = dmaengine_prep_slave_sg(i2c->dmach, &i2c->sg_io[1], 1,
DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
dev_err(i2c->dev,
"Failed to get DMA data write descriptor.\n");
goto read_init_dma_fail;
}
} else {
i2c->dma_read = 0;
i2c->addr_data = (msg->addr << 1) | I2C_SMBUS_WRITE;
/*
* WRITE command.
*/
/* Queue the PIO register write transfer. */
i2c->pio_data[0] = flags | MXS_CMD_I2C_WRITE |
MXS_I2C_CTRL0_XFER_COUNT(msg->len + 1);
desc = dmaengine_prep_slave_sg(i2c->dmach,
(struct scatterlist *)&i2c->pio_data[0],
1, DMA_TRANS_NONE, 0);
if (!desc) {
dev_err(i2c->dev,
"Failed to get PIO reg. write descriptor.\n");
goto write_init_pio_fail;
}
/* Queue the DMA data transfer. */
sg_init_table(i2c->sg_io, 2);
sg_set_buf(&i2c->sg_io[0], &i2c->addr_data, 1);
sg_set_buf(&i2c->sg_io[1], msg->buf, msg->len);
dma_map_sg(i2c->dev, i2c->sg_io, 2, DMA_TO_DEVICE);
desc = dmaengine_prep_slave_sg(i2c->dmach, i2c->sg_io, 2,
DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
dev_err(i2c->dev,
"Failed to get DMA data write descriptor.\n");
goto write_init_dma_fail;
}
}
/*
* The last descriptor must have this callback,
* to finish the DMA transaction.
*/
desc->callback = mxs_i2c_dma_irq_callback;
desc->callback_param = i2c;
/* Start the transfer. */
dmaengine_submit(desc);
dma_async_issue_pending(i2c->dmach);
return 0;
/* Read failpath. */
read_init_dma_fail:
dma_unmap_sg(i2c->dev, &i2c->sg_io[1], 1, DMA_FROM_DEVICE);
select_init_dma_fail:
dma_unmap_sg(i2c->dev, &i2c->sg_io[0], 1, DMA_TO_DEVICE);
select_init_pio_fail:
dmaengine_terminate_all(i2c->dmach);
return -EINVAL;
/* Write failpath. */
write_init_dma_fail:
dma_unmap_sg(i2c->dev, i2c->sg_io, 2, DMA_TO_DEVICE);
write_init_pio_fail:
dmaengine_terminate_all(i2c->dmach);
return -EINVAL;
}
static int mxs_i2c_pio_wait_dmareq(struct mxs_i2c_dev *i2c)
{
unsigned long timeout = jiffies + msecs_to_jiffies(1000);
while (!(readl(i2c->regs + MXS_I2C_DEBUG0) &
MXS_I2C_DEBUG0_DMAREQ)) {
if (time_after(jiffies, timeout))
return -ETIMEDOUT;
cond_resched();
}
return 0;
}
static int mxs_i2c_pio_wait_cplt(struct mxs_i2c_dev *i2c, int last)
{
unsigned long timeout = jiffies + msecs_to_jiffies(1000);
/*
* We do not use interrupts in the PIO mode. Due to the
* maximum transfer length being 8 bytes in PIO mode, the
* overhead of interrupt would be too large and this would
* neglect the gain from using the PIO mode.
*/
while (!(readl(i2c->regs + MXS_I2C_CTRL1) &
MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ)) {
if (time_after(jiffies, timeout))
return -ETIMEDOUT;
cond_resched();
}
writel(MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ,
i2c->regs + MXS_I2C_CTRL1_CLR);
/*
* When ending a transfer with a stop, we have to wait for the bus to
* go idle before we report the transfer as completed. Otherwise the
* start of the next transfer may race with the end of the current one.
*/
while (last && (readl(i2c->regs + MXS_I2C_STAT) &
(MXS_I2C_STAT_BUS_BUSY | MXS_I2C_STAT_CLK_GEN_BUSY))) {
if (time_after(jiffies, timeout))
return -ETIMEDOUT;
cond_resched();
}
return 0;
}
static int mxs_i2c_pio_check_error_state(struct mxs_i2c_dev *i2c)
{
u32 state;
state = readl(i2c->regs + MXS_I2C_CTRL1_CLR) & MXS_I2C_IRQ_MASK;
if (state & MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ)
i2c->cmd_err = -ENXIO;
else if (state & (MXS_I2C_CTRL1_EARLY_TERM_IRQ |
MXS_I2C_CTRL1_MASTER_LOSS_IRQ |
MXS_I2C_CTRL1_SLAVE_STOP_IRQ |
MXS_I2C_CTRL1_SLAVE_IRQ))
i2c->cmd_err = -EIO;
return i2c->cmd_err;
}
static void mxs_i2c_pio_trigger_cmd(struct mxs_i2c_dev *i2c, u32 cmd)
{
u32 reg;
writel(cmd, i2c->regs + MXS_I2C_CTRL0);
/* readback makes sure the write is latched into hardware */
reg = readl(i2c->regs + MXS_I2C_CTRL0);
reg |= MXS_I2C_CTRL0_RUN;
writel(reg, i2c->regs + MXS_I2C_CTRL0);
}
static int mxs_i2c_pio_setup_xfer(struct i2c_adapter *adap,
struct i2c_msg *msg, uint32_t flags)
{
struct mxs_i2c_dev *i2c = i2c_get_adapdata(adap);
uint32_t addr_data = msg->addr << 1;
uint32_t data = 0;
int i, shifts_left, ret;
/* Mute IRQs coming from this block. */
writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_CLR);
if (msg->flags & I2C_M_RD) {
addr_data |= I2C_SMBUS_READ;
/* SELECT command. */
mxs_i2c_pio_trigger_cmd(i2c, MXS_CMD_I2C_SELECT);
ret = mxs_i2c_pio_wait_dmareq(i2c);
if (ret)
return ret;
writel(addr_data, i2c->regs + MXS_I2C_DATA);
writel(MXS_I2C_DEBUG0_DMAREQ, i2c->regs + MXS_I2C_DEBUG0_CLR);
ret = mxs_i2c_pio_wait_cplt(i2c, 0);
if (ret)
return ret;
if (mxs_i2c_pio_check_error_state(i2c))
goto cleanup;
/* READ command. */
mxs_i2c_pio_trigger_cmd(i2c,
MXS_CMD_I2C_READ | flags |
MXS_I2C_CTRL0_XFER_COUNT(msg->len));
for (i = 0; i < msg->len; i++) {
if ((i & 3) == 0) {
ret = mxs_i2c_pio_wait_dmareq(i2c);
if (ret)
return ret;
data = readl(i2c->regs + MXS_I2C_DATA);
writel(MXS_I2C_DEBUG0_DMAREQ,
i2c->regs + MXS_I2C_DEBUG0_CLR);
}
msg->buf[i] = data & 0xff;
data >>= 8;
}
} else {
addr_data |= I2C_SMBUS_WRITE;
/* WRITE command. */
mxs_i2c_pio_trigger_cmd(i2c,
MXS_CMD_I2C_WRITE | flags |
MXS_I2C_CTRL0_XFER_COUNT(msg->len + 1));
/*
* The LSB of data buffer is the first byte blasted across
* the bus. Higher order bytes follow. Thus the following
* filling schematic.
*/
data = addr_data << 24;
for (i = 0; i < msg->len; i++) {
data >>= 8;
data |= (msg->buf[i] << 24);
if ((i & 3) == 2) {
ret = mxs_i2c_pio_wait_dmareq(i2c);
if (ret)
return ret;
writel(data, i2c->regs + MXS_I2C_DATA);
writel(MXS_I2C_DEBUG0_DMAREQ,
i2c->regs + MXS_I2C_DEBUG0_CLR);
}
}
shifts_left = 24 - (i & 3) * 8;
if (shifts_left) {
data >>= shifts_left;
ret = mxs_i2c_pio_wait_dmareq(i2c);
if (ret)
return ret;
writel(data, i2c->regs + MXS_I2C_DATA);
writel(MXS_I2C_DEBUG0_DMAREQ,
i2c->regs + MXS_I2C_DEBUG0_CLR);
}
}
ret = mxs_i2c_pio_wait_cplt(i2c, flags & MXS_I2C_CTRL0_POST_SEND_STOP);
if (ret)
return ret;
/* make sure we capture any occurred error into cmd_err */
mxs_i2c_pio_check_error_state(i2c);
cleanup:
/* Clear any dangling IRQs and re-enable interrupts. */
writel(MXS_I2C_IRQ_MASK, i2c->regs + MXS_I2C_CTRL1_CLR);
writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
return 0;
}
/*
* Low level master read/write transaction.
*/
static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
int stop)
{
struct mxs_i2c_dev *i2c = i2c_get_adapdata(adap);
int ret;
int flags;
flags = stop ? MXS_I2C_CTRL0_POST_SEND_STOP : 0;
dev_dbg(i2c->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
msg->addr, msg->len, msg->flags, stop);
if (msg->len == 0)
return -EINVAL;
/*
* The current boundary to select between PIO/DMA transfer method
* is set to 8 bytes, transfers shorter than 8 bytes are transfered
* using PIO mode while longer transfers use DMA. The 8 byte border is
* based on this empirical measurement and a lot of previous frobbing.
*/
i2c->cmd_err = 0;
if (msg->len < 8) {
ret = mxs_i2c_pio_setup_xfer(adap, msg, flags);
if (ret)
mxs_i2c_reset(i2c);
} else {
INIT_COMPLETION(i2c->cmd_complete);
ret = mxs_i2c_dma_setup_xfer(adap, msg, flags);
if (ret)
return ret;
ret = wait_for_completion_timeout(&i2c->cmd_complete,
msecs_to_jiffies(1000));
if (ret == 0)
goto timeout;
}
if (i2c->cmd_err == -ENXIO) {
/*
* If the transfer fails with a NAK from the slave the
* controller halts until it gets told to return to idle state.
*/
writel(MXS_I2C_CTRL1_CLR_GOT_A_NAK,
i2c->regs + MXS_I2C_CTRL1_SET);
}
ret = i2c->cmd_err;
dev_dbg(i2c->dev, "Done with err=%d\n", ret);
return ret;
timeout:
dev_dbg(i2c->dev, "Timeout!\n");
mxs_i2c_dma_finish(i2c);
mxs_i2c_reset(i2c);
return -ETIMEDOUT;
}
static int mxs_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
int num)
{
int i;
int err;
for (i = 0; i < num; i++) {
err = mxs_i2c_xfer_msg(adap, &msgs[i], i == (num - 1));
if (err)
return err;
}
return num;
}
static u32 mxs_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static irqreturn_t mxs_i2c_isr(int this_irq, void *dev_id)
{
struct mxs_i2c_dev *i2c = dev_id;
u32 stat = readl(i2c->regs + MXS_I2C_CTRL1) & MXS_I2C_IRQ_MASK;
if (!stat)
return IRQ_NONE;
if (stat & MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ)
i2c->cmd_err = -ENXIO;
else if (stat & (MXS_I2C_CTRL1_EARLY_TERM_IRQ |
MXS_I2C_CTRL1_MASTER_LOSS_IRQ |
MXS_I2C_CTRL1_SLAVE_STOP_IRQ | MXS_I2C_CTRL1_SLAVE_IRQ))
/* MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ is only for slaves */
i2c->cmd_err = -EIO;
writel(stat, i2c->regs + MXS_I2C_CTRL1_CLR);
return IRQ_HANDLED;
}
static const struct i2c_algorithm mxs_i2c_algo = {
.master_xfer = mxs_i2c_xfer,
.functionality = mxs_i2c_func,
};
static void mxs_i2c_derive_timing(struct mxs_i2c_dev *i2c, int speed)
{
/* The I2C block clock run at 24MHz */
const uint32_t clk = 24000000;
uint32_t base;
uint16_t high_count, low_count, rcv_count, xmit_count;
struct device *dev = i2c->dev;
if (speed > 540000) {
dev_warn(dev, "Speed too high (%d Hz), using 540 kHz\n", speed);
speed = 540000;
} else if (speed < 12000) {
dev_warn(dev, "Speed too low (%d Hz), using 12 kHz\n", speed);
speed = 12000;
}
/*
* The timing derivation algorithm. There is no documentation for this
* algorithm available, it was derived by using the scope and fiddling
* with constants until the result observed on the scope was good enough
* for 20kHz, 50kHz, 100kHz, 200kHz, 300kHz and 400kHz. It should be
* possible to assume the algorithm works for other frequencies as well.
*
* Note it was necessary to cap the frequency on both ends as it's not
* possible to configure completely arbitrary frequency for the I2C bus
* clock.
*/
base = ((clk / speed) - 38) / 2;
high_count = base + 3;
low_count = base - 3;
rcv_count = (high_count * 3) / 4;
xmit_count = low_count / 4;
i2c->timing0 = (high_count << 16) | rcv_count;
i2c->timing1 = (low_count << 16) | xmit_count;
}
static int mxs_i2c_get_ofdata(struct mxs_i2c_dev *i2c)
{
uint32_t speed;
struct device *dev = i2c->dev;
struct device_node *node = dev->of_node;
int ret;
ret = of_property_read_u32(node, "clock-frequency", &speed);
if (ret) {
dev_warn(dev, "No I2C speed selected, using 100kHz\n");
speed = 100000;
}
mxs_i2c_derive_timing(i2c, speed);
return 0;
}
static int mxs_i2c_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct mxs_i2c_dev *i2c;
struct i2c_adapter *adap;
struct pinctrl *pinctrl;
struct resource *res;
resource_size_t res_size;
int err, irq;
pinctrl = devm_pinctrl_get_select_default(dev);
if (IS_ERR(pinctrl))
return PTR_ERR(pinctrl);
i2c = devm_kzalloc(dev, sizeof(struct mxs_i2c_dev), GFP_KERNEL);
if (!i2c)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
irq = platform_get_irq(pdev, 0);
if (!res || irq < 0)
return -ENOENT;
res_size = resource_size(res);
if (!devm_request_mem_region(dev, res->start, res_size, res->name))
return -EBUSY;
i2c->regs = devm_ioremap_nocache(dev, res->start, res_size);
if (!i2c->regs)
return -EBUSY;
err = devm_request_irq(dev, irq, mxs_i2c_isr, 0, dev_name(dev), i2c);
if (err)
return err;
i2c->dev = dev;
init_completion(&i2c->cmd_complete);
if (dev->of_node) {
err = mxs_i2c_get_ofdata(i2c);
if (err)
return err;
}
/* Setup the DMA */
i2c->dmach = dma_request_slave_channel(dev, "rx-tx");
if (!i2c->dmach) {
dev_err(dev, "Failed to request dma\n");
return -ENODEV;
}
platform_set_drvdata(pdev, i2c);
/* Do reset to enforce correct startup after pinmuxing */
mxs_i2c_reset(i2c);
adap = &i2c->adapter;
strlcpy(adap->name, "MXS I2C adapter", sizeof(adap->name));
adap->owner = THIS_MODULE;
adap->algo = &mxs_i2c_algo;
adap->dev.parent = dev;
adap->nr = pdev->id;
adap->dev.of_node = pdev->dev.of_node;
i2c_set_adapdata(adap, i2c);
err = i2c_add_numbered_adapter(adap);
if (err) {
dev_err(dev, "Failed to add adapter (%d)\n", err);
writel(MXS_I2C_CTRL0_SFTRST,
i2c->regs + MXS_I2C_CTRL0_SET);
return err;
}
of_i2c_register_devices(adap);
return 0;
}
static int mxs_i2c_remove(struct platform_device *pdev)
{
struct mxs_i2c_dev *i2c = platform_get_drvdata(pdev);
i2c_del_adapter(&i2c->adapter);
if (i2c->dmach)
dma_release_channel(i2c->dmach);
writel(MXS_I2C_CTRL0_SFTRST, i2c->regs + MXS_I2C_CTRL0_SET);
return 0;
}
static const struct of_device_id mxs_i2c_dt_ids[] = {
{ .compatible = "fsl,imx28-i2c", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxs_i2c_dt_ids);
static struct platform_driver mxs_i2c_driver = {
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
.of_match_table = mxs_i2c_dt_ids,
},
.remove = mxs_i2c_remove,
};
static int __init mxs_i2c_init(void)
{
return platform_driver_probe(&mxs_i2c_driver, mxs_i2c_probe);
}
subsys_initcall(mxs_i2c_init);
static void __exit mxs_i2c_exit(void)
{
platform_driver_unregister(&mxs_i2c_driver);
}
module_exit(mxs_i2c_exit);
MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
MODULE_DESCRIPTION("MXS I2C Bus Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRIVER_NAME);