UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity
OpenCloudOS-Kernel/drivers/i2c/busses/i2c-imx.c

1271 lines
35 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2002 Motorola GSG-China
*
* Author:
* Darius Augulis, Teltonika Inc.
*
* Desc.:
* Implementation of I2C Adapter/Algorithm Driver
* for I2C Bus integrated in Freescale i.MX/MXC processors
*
* Derived from Motorola GSG China I2C example driver
*
* Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de
* Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de
* Copyright (C) 2007 RightHand Technologies, Inc.
* Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt>
*
* Copyright 2013 Freescale Semiconductor, Inc.
*
*/
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/dmapool.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_dma.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_data/i2c-imx.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/sched.h>
#include <linux/slab.h>
/* This will be the driver name the kernel reports */
#define DRIVER_NAME "imx-i2c"
/* Default value */
#define IMX_I2C_BIT_RATE 100000 /* 100kHz */
/*
* Enable DMA if transfer byte size is bigger than this threshold.
* As the hardware request, it must bigger than 4 bytes.\
* I have set '16' here, maybe it's not the best but I think it's
* the appropriate.
*/
#define DMA_THRESHOLD 16
#define DMA_TIMEOUT 1000
/* IMX I2C registers:
* the I2C register offset is different between SoCs,
* to provid support for all these chips, split the
* register offset into a fixed base address and a
* variable shift value, then the full register offset
* will be calculated by
* reg_off = ( reg_base_addr << reg_shift)
*/
#define IMX_I2C_IADR 0x00 /* i2c slave address */
#define IMX_I2C_IFDR 0x01 /* i2c frequency divider */
#define IMX_I2C_I2CR 0x02 /* i2c control */
#define IMX_I2C_I2SR 0x03 /* i2c status */
#define IMX_I2C_I2DR 0x04 /* i2c transfer data */
#define IMX_I2C_REGSHIFT 2
#define VF610_I2C_REGSHIFT 0
/* Bits of IMX I2C registers */
#define I2SR_RXAK 0x01
#define I2SR_IIF 0x02
#define I2SR_SRW 0x04
#define I2SR_IAL 0x10
#define I2SR_IBB 0x20
#define I2SR_IAAS 0x40
#define I2SR_ICF 0x80
#define I2CR_DMAEN 0x02
#define I2CR_RSTA 0x04
#define I2CR_TXAK 0x08
#define I2CR_MTX 0x10
#define I2CR_MSTA 0x20
#define I2CR_IIEN 0x40
#define I2CR_IEN 0x80
/* register bits different operating codes definition:
* 1) I2SR: Interrupt flags clear operation differ between SoCs:
* - write zero to clear(w0c) INT flag on i.MX,
* - but write one to clear(w1c) INT flag on Vybrid.
* 2) I2CR: I2C module enable operation also differ between SoCs:
* - set I2CR_IEN bit enable the module on i.MX,
* - but clear I2CR_IEN bit enable the module on Vybrid.
*/
#define I2SR_CLR_OPCODE_W0C 0x0
#define I2SR_CLR_OPCODE_W1C (I2SR_IAL | I2SR_IIF)
#define I2CR_IEN_OPCODE_0 0x0
#define I2CR_IEN_OPCODE_1 I2CR_IEN
#define I2C_PM_TIMEOUT 10 /* ms */
/*
* sorted list of clock divider, register value pairs
* taken from table 26-5, p.26-9, Freescale i.MX
* Integrated Portable System Processor Reference Manual
* Document Number: MC9328MXLRM, Rev. 5.1, 06/2007
*
* Duplicated divider values removed from list
*/
struct imx_i2c_clk_pair {
u16 div;
u16 val;
};
static struct imx_i2c_clk_pair imx_i2c_clk_div[] = {
{ 22, 0x20 }, { 24, 0x21 }, { 26, 0x22 }, { 28, 0x23 },
{ 30, 0x00 }, { 32, 0x24 }, { 36, 0x25 }, { 40, 0x26 },
{ 42, 0x03 }, { 44, 0x27 }, { 48, 0x28 }, { 52, 0x05 },
{ 56, 0x29 }, { 60, 0x06 }, { 64, 0x2A }, { 72, 0x2B },
{ 80, 0x2C }, { 88, 0x09 }, { 96, 0x2D }, { 104, 0x0A },
{ 112, 0x2E }, { 128, 0x2F }, { 144, 0x0C }, { 160, 0x30 },
{ 192, 0x31 }, { 224, 0x32 }, { 240, 0x0F }, { 256, 0x33 },
{ 288, 0x10 }, { 320, 0x34 }, { 384, 0x35 }, { 448, 0x36 },
{ 480, 0x13 }, { 512, 0x37 }, { 576, 0x14 }, { 640, 0x38 },
{ 768, 0x39 }, { 896, 0x3A }, { 960, 0x17 }, { 1024, 0x3B },
{ 1152, 0x18 }, { 1280, 0x3C }, { 1536, 0x3D }, { 1792, 0x3E },
{ 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D },
{ 3072, 0x1E }, { 3840, 0x1F }
};
/* Vybrid VF610 clock divider, register value pairs */
static struct imx_i2c_clk_pair vf610_i2c_clk_div[] = {
{ 20, 0x00 }, { 22, 0x01 }, { 24, 0x02 }, { 26, 0x03 },
{ 28, 0x04 }, { 30, 0x05 }, { 32, 0x09 }, { 34, 0x06 },
{ 36, 0x0A }, { 40, 0x07 }, { 44, 0x0C }, { 48, 0x0D },
{ 52, 0x43 }, { 56, 0x0E }, { 60, 0x45 }, { 64, 0x12 },
{ 68, 0x0F }, { 72, 0x13 }, { 80, 0x14 }, { 88, 0x15 },
{ 96, 0x19 }, { 104, 0x16 }, { 112, 0x1A }, { 128, 0x17 },
{ 136, 0x4F }, { 144, 0x1C }, { 160, 0x1D }, { 176, 0x55 },
{ 192, 0x1E }, { 208, 0x56 }, { 224, 0x22 }, { 228, 0x24 },
{ 240, 0x1F }, { 256, 0x23 }, { 288, 0x5C }, { 320, 0x25 },
{ 384, 0x26 }, { 448, 0x2A }, { 480, 0x27 }, { 512, 0x2B },
{ 576, 0x2C }, { 640, 0x2D }, { 768, 0x31 }, { 896, 0x32 },
{ 960, 0x2F }, { 1024, 0x33 }, { 1152, 0x34 }, { 1280, 0x35 },
{ 1536, 0x36 }, { 1792, 0x3A }, { 1920, 0x37 }, { 2048, 0x3B },
{ 2304, 0x3C }, { 2560, 0x3D }, { 3072, 0x3E }, { 3584, 0x7A },
{ 3840, 0x3F }, { 4096, 0x7B }, { 5120, 0x7D }, { 6144, 0x7E },
};
enum imx_i2c_type {
IMX1_I2C,
IMX21_I2C,
VF610_I2C,
};
struct imx_i2c_hwdata {
enum imx_i2c_type devtype;
unsigned regshift;
struct imx_i2c_clk_pair *clk_div;
unsigned ndivs;
unsigned i2sr_clr_opcode;
unsigned i2cr_ien_opcode;
};
struct imx_i2c_dma {
struct dma_chan *chan_tx;
struct dma_chan *chan_rx;
struct dma_chan *chan_using;
struct completion cmd_complete;
dma_addr_t dma_buf;
unsigned int dma_len;
enum dma_transfer_direction dma_transfer_dir;
enum dma_data_direction dma_data_dir;
};
struct imx_i2c_struct {
struct i2c_adapter adapter;
struct clk *clk;
struct notifier_block clk_change_nb;
void __iomem *base;
wait_queue_head_t queue;
unsigned long i2csr;
unsigned int disable_delay;
int stopped;
unsigned int ifdr; /* IMX_I2C_IFDR */
unsigned int cur_clk;
unsigned int bitrate;
const struct imx_i2c_hwdata *hwdata;
struct i2c_bus_recovery_info rinfo;
struct pinctrl *pinctrl;
struct pinctrl_state *pinctrl_pins_default;
struct pinctrl_state *pinctrl_pins_gpio;
struct imx_i2c_dma *dma;
};
static const struct imx_i2c_hwdata imx1_i2c_hwdata = {
.devtype = IMX1_I2C,
.regshift = IMX_I2C_REGSHIFT,
.clk_div = imx_i2c_clk_div,
.ndivs = ARRAY_SIZE(imx_i2c_clk_div),
.i2sr_clr_opcode = I2SR_CLR_OPCODE_W0C,
.i2cr_ien_opcode = I2CR_IEN_OPCODE_1,
};
static const struct imx_i2c_hwdata imx21_i2c_hwdata = {
.devtype = IMX21_I2C,
.regshift = IMX_I2C_REGSHIFT,
.clk_div = imx_i2c_clk_div,
.ndivs = ARRAY_SIZE(imx_i2c_clk_div),
.i2sr_clr_opcode = I2SR_CLR_OPCODE_W0C,
.i2cr_ien_opcode = I2CR_IEN_OPCODE_1,
};
static struct imx_i2c_hwdata vf610_i2c_hwdata = {
.devtype = VF610_I2C,
.regshift = VF610_I2C_REGSHIFT,
.clk_div = vf610_i2c_clk_div,
.ndivs = ARRAY_SIZE(vf610_i2c_clk_div),
.i2sr_clr_opcode = I2SR_CLR_OPCODE_W1C,
.i2cr_ien_opcode = I2CR_IEN_OPCODE_0,
};
static const struct platform_device_id imx_i2c_devtype[] = {
{
.name = "imx1-i2c",
.driver_data = (kernel_ulong_t)&imx1_i2c_hwdata,
}, {
.name = "imx21-i2c",
.driver_data = (kernel_ulong_t)&imx21_i2c_hwdata,
}, {
/* sentinel */
}
};
MODULE_DEVICE_TABLE(platform, imx_i2c_devtype);
static const struct of_device_id i2c_imx_dt_ids[] = {
{ .compatible = "fsl,imx1-i2c", .data = &imx1_i2c_hwdata, },
{ .compatible = "fsl,imx21-i2c", .data = &imx21_i2c_hwdata, },
{ .compatible = "fsl,vf610-i2c", .data = &vf610_i2c_hwdata, },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, i2c_imx_dt_ids);
static inline int is_imx1_i2c(struct imx_i2c_struct *i2c_imx)
{
return i2c_imx->hwdata->devtype == IMX1_I2C;
}
static inline void imx_i2c_write_reg(unsigned int val,
struct imx_i2c_struct *i2c_imx, unsigned int reg)
{
writeb(val, i2c_imx->base + (reg << i2c_imx->hwdata->regshift));
}
static inline unsigned char imx_i2c_read_reg(struct imx_i2c_struct *i2c_imx,
unsigned int reg)
{
return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift));
}
/* Functions for DMA support */
static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
dma_addr_t phy_addr)
{
struct imx_i2c_dma *dma;
struct dma_slave_config dma_sconfig;
struct device *dev = &i2c_imx->adapter.dev;
int ret;
dma = devm_kzalloc(dev, sizeof(*dma), GFP_KERNEL);
if (!dma)
return;
dma->chan_tx = dma_request_slave_channel(dev, "tx");
if (!dma->chan_tx) {
dev_dbg(dev, "can't request DMA tx channel\n");
goto fail_al;
}
dma_sconfig.dst_addr = phy_addr +
(IMX_I2C_I2DR << i2c_imx->hwdata->regshift);
dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
dma_sconfig.dst_maxburst = 1;
dma_sconfig.direction = DMA_MEM_TO_DEV;
ret = dmaengine_slave_config(dma->chan_tx, &dma_sconfig);
if (ret < 0) {
dev_dbg(dev, "can't configure tx channel\n");
goto fail_tx;
}
dma->chan_rx = dma_request_slave_channel(dev, "rx");
if (!dma->chan_rx) {
dev_dbg(dev, "can't request DMA rx channel\n");
goto fail_tx;
}
dma_sconfig.src_addr = phy_addr +
(IMX_I2C_I2DR << i2c_imx->hwdata->regshift);
dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
dma_sconfig.src_maxburst = 1;
dma_sconfig.direction = DMA_DEV_TO_MEM;
ret = dmaengine_slave_config(dma->chan_rx, &dma_sconfig);
if (ret < 0) {
dev_dbg(dev, "can't configure rx channel\n");
goto fail_rx;
}
i2c_imx->dma = dma;
init_completion(&dma->cmd_complete);
dev_info(dev, "using %s (tx) and %s (rx) for DMA transfers\n",
dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx));
return;
fail_rx:
dma_release_channel(dma->chan_rx);
fail_tx:
dma_release_channel(dma->chan_tx);
fail_al:
devm_kfree(dev, dma);
dev_info(dev, "can't use DMA, using PIO instead.\n");
}
static void i2c_imx_dma_callback(void *arg)
{
struct imx_i2c_struct *i2c_imx = (struct imx_i2c_struct *)arg;
struct imx_i2c_dma *dma = i2c_imx->dma;
dma_unmap_single(dma->chan_using->device->dev, dma->dma_buf,
dma->dma_len, dma->dma_data_dir);
complete(&dma->cmd_complete);
}
static int i2c_imx_dma_xfer(struct imx_i2c_struct *i2c_imx,
struct i2c_msg *msgs)
{
struct imx_i2c_dma *dma = i2c_imx->dma;
struct dma_async_tx_descriptor *txdesc;
struct device *dev = &i2c_imx->adapter.dev;
struct device *chan_dev = dma->chan_using->device->dev;
dma->dma_buf = dma_map_single(chan_dev, msgs->buf,
dma->dma_len, dma->dma_data_dir);
if (dma_mapping_error(chan_dev, dma->dma_buf)) {
dev_err(dev, "DMA mapping failed\n");
goto err_map;
}
txdesc = dmaengine_prep_slave_single(dma->chan_using, dma->dma_buf,
dma->dma_len, dma->dma_transfer_dir,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!txdesc) {
dev_err(dev, "Not able to get desc for DMA xfer\n");
goto err_desc;
}
reinit_completion(&dma->cmd_complete);
txdesc->callback = i2c_imx_dma_callback;
txdesc->callback_param = i2c_imx;
if (dma_submit_error(dmaengine_submit(txdesc))) {
dev_err(dev, "DMA submit failed\n");
goto err_submit;
}
dma_async_issue_pending(dma->chan_using);
return 0;
err_submit:
dmaengine_terminate_all(dma->chan_using);
err_desc:
dma_unmap_single(chan_dev, dma->dma_buf,
dma->dma_len, dma->dma_data_dir);
err_map:
return -EINVAL;
}
static void i2c_imx_dma_free(struct imx_i2c_struct *i2c_imx)
{
struct imx_i2c_dma *dma = i2c_imx->dma;
dma->dma_buf = 0;
dma->dma_len = 0;
dma_release_channel(dma->chan_tx);
dma->chan_tx = NULL;
dma_release_channel(dma->chan_rx);
dma->chan_rx = NULL;
dma->chan_using = NULL;
}
static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy)
{
unsigned long orig_jiffies = jiffies;
unsigned int temp;
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
while (1) {
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
/* check for arbitration lost */
if (temp & I2SR_IAL) {
temp &= ~I2SR_IAL;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
return -EAGAIN;
}
if (for_busy && (temp & I2SR_IBB)) {
i2c_imx->stopped = 0;
break;
}
if (!for_busy && !(temp & I2SR_IBB)) {
i2c_imx->stopped = 1;
break;
}
if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
dev_dbg(&i2c_imx->adapter.dev,
"<%s> I2C bus is busy\n", __func__);
return -ETIMEDOUT;
}
schedule();
}
return 0;
}
static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
{
wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10);
if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
return -ETIMEDOUT;
}
dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__);
i2c_imx->i2csr = 0;
return 0;
}
static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx)
{
if (imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR) & I2SR_RXAK) {
dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__);
return -ENXIO; /* No ACK */
}
dev_dbg(&i2c_imx->adapter.dev, "<%s> ACK received\n", __func__);
return 0;
}
static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
unsigned int i2c_clk_rate)
{
struct imx_i2c_clk_pair *i2c_clk_div = i2c_imx->hwdata->clk_div;
unsigned int div;
int i;
/* Divider value calculation */
if (i2c_imx->cur_clk == i2c_clk_rate)
return;
i2c_imx->cur_clk = i2c_clk_rate;
div = (i2c_clk_rate + i2c_imx->bitrate - 1) / i2c_imx->bitrate;
if (div < i2c_clk_div[0].div)
i = 0;
else if (div > i2c_clk_div[i2c_imx->hwdata->ndivs - 1].div)
i = i2c_imx->hwdata->ndivs - 1;
else
for (i = 0; i2c_clk_div[i].div < div; i++)
;
/* Store divider value */
i2c_imx->ifdr = i2c_clk_div[i].val;
/*
* There dummy delay is calculated.
* It should be about one I2C clock period long.
* This delay is used in I2C bus disable function
* to fix chip hardware bug.
*/
i2c_imx->disable_delay = (500000U * i2c_clk_div[i].div
+ (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2);
#ifdef CONFIG_I2C_DEBUG_BUS
dev_dbg(&i2c_imx->adapter.dev, "I2C_CLK=%d, REQ DIV=%d\n",
i2c_clk_rate, div);
dev_dbg(&i2c_imx->adapter.dev, "IFDR[IC]=0x%x, REAL DIV=%d\n",
i2c_clk_div[i].val, i2c_clk_div[i].div);
#endif
}
static int i2c_imx_clk_notifier_call(struct notifier_block *nb,
unsigned long action, void *data)
{
struct clk_notifier_data *ndata = data;
struct imx_i2c_struct *i2c_imx = container_of(&ndata->clk,
struct imx_i2c_struct,
clk);
if (action & POST_RATE_CHANGE)
i2c_imx_set_clk(i2c_imx, ndata->new_rate);
return NOTIFY_OK;
}
static int i2c_imx_start(struct imx_i2c_struct *i2c_imx)
{
unsigned int temp = 0;
int result;
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
imx_i2c_write_reg(i2c_imx->ifdr, i2c_imx, IMX_I2C_IFDR);
/* Enable I2C controller */
imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode, i2c_imx, IMX_I2C_I2CR);
/* Wait controller to be stable */
usleep_range(50, 150);
/* Start I2C transaction */
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp |= I2CR_MSTA;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
result = i2c_imx_bus_busy(i2c_imx, 1);
if (result)
return result;
temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK;
temp &= ~I2CR_DMAEN;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
return result;
}
static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
{
unsigned int temp = 0;
if (!i2c_imx->stopped) {
/* Stop I2C transaction */
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp &= ~(I2CR_MSTA | I2CR_MTX);
if (i2c_imx->dma)
temp &= ~I2CR_DMAEN;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
}
if (is_imx1_i2c(i2c_imx)) {
/*
* This delay caused by an i.MXL hardware bug.
* If no (or too short) delay, no "STOP" bit will be generated.
*/
udelay(i2c_imx->disable_delay);
}
if (!i2c_imx->stopped)
i2c_imx_bus_busy(i2c_imx, 0);
/* Disable I2C controller */
temp = i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
}
static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
{
struct imx_i2c_struct *i2c_imx = dev_id;
unsigned int temp;
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
if (temp & I2SR_IIF) {
/* save status register */
i2c_imx->i2csr = temp;
temp &= ~I2SR_IIF;
temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF);
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
wake_up(&i2c_imx->queue);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx,
struct i2c_msg *msgs)
{
int result;
unsigned long time_left;
unsigned int temp = 0;
unsigned long orig_jiffies = jiffies;
struct imx_i2c_dma *dma = i2c_imx->dma;
struct device *dev = &i2c_imx->adapter.dev;
dma->chan_using = dma->chan_tx;
dma->dma_transfer_dir = DMA_MEM_TO_DEV;
dma->dma_data_dir = DMA_TO_DEVICE;
dma->dma_len = msgs->len - 1;
result = i2c_imx_dma_xfer(i2c_imx, msgs);
if (result)
return result;
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp |= I2CR_DMAEN;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
/*
* Write slave address.
* The first byte must be transmitted by the CPU.
*/
imx_i2c_write_reg(i2c_8bit_addr_from_msg(msgs), i2c_imx, IMX_I2C_I2DR);
time_left = wait_for_completion_timeout(
&i2c_imx->dma->cmd_complete,
msecs_to_jiffies(DMA_TIMEOUT));
if (time_left == 0) {
dmaengine_terminate_all(dma->chan_using);
return -ETIMEDOUT;
}
/* Waiting for transfer complete. */
while (1) {
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
if (temp & I2SR_ICF)
break;
if (time_after(jiffies, orig_jiffies +
msecs_to_jiffies(DMA_TIMEOUT))) {
dev_dbg(dev, "<%s> Timeout\n", __func__);
return -ETIMEDOUT;
}
schedule();
}
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp &= ~I2CR_DMAEN;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
/* The last data byte must be transferred by the CPU. */
imx_i2c_write_reg(msgs->buf[msgs->len-1],
i2c_imx, IMX_I2C_I2DR);
result = i2c_imx_trx_complete(i2c_imx);
if (result)
return result;
return i2c_imx_acked(i2c_imx);
}
static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx,
struct i2c_msg *msgs, bool is_lastmsg)
{
int result;
unsigned long time_left;
unsigned int temp;
unsigned long orig_jiffies = jiffies;
struct imx_i2c_dma *dma = i2c_imx->dma;
struct device *dev = &i2c_imx->adapter.dev;
dma->chan_using = dma->chan_rx;
dma->dma_transfer_dir = DMA_DEV_TO_MEM;
dma->dma_data_dir = DMA_FROM_DEVICE;
/* The last two data bytes must be transferred by the CPU. */
dma->dma_len = msgs->len - 2;
result = i2c_imx_dma_xfer(i2c_imx, msgs);
if (result)
return result;
time_left = wait_for_completion_timeout(
&i2c_imx->dma->cmd_complete,
msecs_to_jiffies(DMA_TIMEOUT));
if (time_left == 0) {
dmaengine_terminate_all(dma->chan_using);
return -ETIMEDOUT;
}
/* waiting for transfer complete. */
while (1) {
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
if (temp & I2SR_ICF)
break;
if (time_after(jiffies, orig_jiffies +
msecs_to_jiffies(DMA_TIMEOUT))) {
dev_dbg(dev, "<%s> Timeout\n", __func__);
return -ETIMEDOUT;
}
schedule();
}
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp &= ~I2CR_DMAEN;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
/* read n-1 byte data */
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp |= I2CR_TXAK;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
msgs->buf[msgs->len-2] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
/* read n byte data */
result = i2c_imx_trx_complete(i2c_imx);
if (result)
return result;
if (is_lastmsg) {
/*
* It must generate STOP before read I2DR to prevent
* controller from generating another clock cycle
*/
dev_dbg(dev, "<%s> clear MSTA\n", __func__);
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp &= ~(I2CR_MSTA | I2CR_MTX);
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
i2c_imx_bus_busy(i2c_imx, 0);
} else {
/*
* For i2c master receiver repeat restart operation like:
* read -> repeat MSTA -> read/write
* The controller must set MTX before read the last byte in
* the first read operation, otherwise the first read cost
* one extra clock cycle.
*/
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp |= I2CR_MTX;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
}
msgs->buf[msgs->len-1] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
return 0;
}
static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs)
{
int i, result;
dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n",
__func__, i2c_8bit_addr_from_msg(msgs));
/* write slave address */
imx_i2c_write_reg(i2c_8bit_addr_from_msg(msgs), i2c_imx, IMX_I2C_I2DR);
result = i2c_imx_trx_complete(i2c_imx);
if (result)
return result;
result = i2c_imx_acked(i2c_imx);
if (result)
return result;
dev_dbg(&i2c_imx->adapter.dev, "<%s> write data\n", __func__);
/* write data */
for (i = 0; i < msgs->len; i++) {
dev_dbg(&i2c_imx->adapter.dev,
"<%s> write byte: B%d=0x%X\n",
__func__, i, msgs->buf[i]);
imx_i2c_write_reg(msgs->buf[i], i2c_imx, IMX_I2C_I2DR);
result = i2c_imx_trx_complete(i2c_imx);
if (result)
return result;
result = i2c_imx_acked(i2c_imx);
if (result)
return result;
}
return 0;
}
static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, bool is_lastmsg)
{
int i, result;
unsigned int temp;
int block_data = msgs->flags & I2C_M_RECV_LEN;
int use_dma = i2c_imx->dma && msgs->len >= DMA_THRESHOLD && !block_data;
dev_dbg(&i2c_imx->adapter.dev,
"<%s> write slave address: addr=0x%x\n",
__func__, i2c_8bit_addr_from_msg(msgs));
/* write slave address */
imx_i2c_write_reg(i2c_8bit_addr_from_msg(msgs), i2c_imx, IMX_I2C_I2DR);
result = i2c_imx_trx_complete(i2c_imx);
if (result)
return result;
result = i2c_imx_acked(i2c_imx);
if (result)
return result;
dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__);
/* setup bus to read data */
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp &= ~I2CR_MTX;
/*
* Reset the I2CR_TXAK flag initially for SMBus block read since the
* length is unknown
*/
if ((msgs->len - 1) || block_data)
temp &= ~I2CR_TXAK;
if (use_dma)
temp |= I2CR_DMAEN;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); /* dummy read */
dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__);
if (use_dma)
return i2c_imx_dma_read(i2c_imx, msgs, is_lastmsg);
/* read data */
for (i = 0; i < msgs->len; i++) {
u8 len = 0;
result = i2c_imx_trx_complete(i2c_imx);
if (result)
return result;
/*
* First byte is the length of remaining packet
* in the SMBus block data read. Add it to
* msgs->len.
*/
if ((!i) && block_data) {
len = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
if ((len == 0) || (len > I2C_SMBUS_BLOCK_MAX))
return -EPROTO;
dev_dbg(&i2c_imx->adapter.dev,
"<%s> read length: 0x%X\n",
__func__, len);
msgs->len += len;
}
if (i == (msgs->len - 1)) {
if (is_lastmsg) {
/*
* It must generate STOP before read I2DR to prevent
* controller from generating another clock cycle
*/
dev_dbg(&i2c_imx->adapter.dev,
"<%s> clear MSTA\n", __func__);
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp &= ~(I2CR_MSTA | I2CR_MTX);
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
i2c_imx_bus_busy(i2c_imx, 0);
} else {
/*
* For i2c master receiver repeat restart operation like:
* read -> repeat MSTA -> read/write
* The controller must set MTX before read the last byte in
* the first read operation, otherwise the first read cost
* one extra clock cycle.
*/
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp |= I2CR_MTX;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
}
} else if (i == (msgs->len - 2)) {
dev_dbg(&i2c_imx->adapter.dev,
"<%s> set TXAK\n", __func__);
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp |= I2CR_TXAK;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
}
if ((!i) && block_data)
msgs->buf[0] = len;
else
msgs->buf[i] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
dev_dbg(&i2c_imx->adapter.dev,
"<%s> read byte: B%d=0x%X\n",
__func__, i, msgs->buf[i]);
}
return 0;
}
static int i2c_imx_xfer(struct i2c_adapter *adapter,
struct i2c_msg *msgs, int num)
{
unsigned int i, temp;
int result;
bool is_lastmsg = false;
struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter);
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
result = pm_runtime_get_sync(i2c_imx->adapter.dev.parent);
if (result < 0)
goto out;
/* Start I2C transfer */
result = i2c_imx_start(i2c_imx);
if (result) {
if (i2c_imx->adapter.bus_recovery_info) {
i2c_recover_bus(&i2c_imx->adapter);
result = i2c_imx_start(i2c_imx);
}
}
if (result)
goto fail0;
/* read/write data */
for (i = 0; i < num; i++) {
if (i == num - 1)
is_lastmsg = true;
if (i) {
dev_dbg(&i2c_imx->adapter.dev,
"<%s> repeated start\n", __func__);
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp |= I2CR_RSTA;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
result = i2c_imx_bus_busy(i2c_imx, 1);
if (result)
goto fail0;
}
dev_dbg(&i2c_imx->adapter.dev,
"<%s> transfer message: %d\n", __func__, i);
/* write/read data */
#ifdef CONFIG_I2C_DEBUG_BUS
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
dev_dbg(&i2c_imx->adapter.dev,
"<%s> CONTROL: IEN=%d, IIEN=%d, MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n",
__func__,
(temp & I2CR_IEN ? 1 : 0), (temp & I2CR_IIEN ? 1 : 0),
(temp & I2CR_MSTA ? 1 : 0), (temp & I2CR_MTX ? 1 : 0),
(temp & I2CR_TXAK ? 1 : 0), (temp & I2CR_RSTA ? 1 : 0));
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
dev_dbg(&i2c_imx->adapter.dev,
"<%s> STATUS: ICF=%d, IAAS=%d, IBB=%d, IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n",
__func__,
(temp & I2SR_ICF ? 1 : 0), (temp & I2SR_IAAS ? 1 : 0),
(temp & I2SR_IBB ? 1 : 0), (temp & I2SR_IAL ? 1 : 0),
(temp & I2SR_SRW ? 1 : 0), (temp & I2SR_IIF ? 1 : 0),
(temp & I2SR_RXAK ? 1 : 0));
#endif
if (msgs[i].flags & I2C_M_RD)
result = i2c_imx_read(i2c_imx, &msgs[i], is_lastmsg);
else {
if (i2c_imx->dma && msgs[i].len >= DMA_THRESHOLD)
result = i2c_imx_dma_write(i2c_imx, &msgs[i]);
else
result = i2c_imx_write(i2c_imx, &msgs[i]);
}
if (result)
goto fail0;
}
fail0:
/* Stop I2C transfer */
i2c_imx_stop(i2c_imx);
pm_runtime_mark_last_busy(i2c_imx->adapter.dev.parent);
pm_runtime_put_autosuspend(i2c_imx->adapter.dev.parent);
out:
dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
(result < 0) ? "error" : "success msg",
(result < 0) ? result : num);
return (result < 0) ? result : num;
}
static void i2c_imx_prepare_recovery(struct i2c_adapter *adap)
{
struct imx_i2c_struct *i2c_imx;
i2c_imx = container_of(adap, struct imx_i2c_struct, adapter);
pinctrl_select_state(i2c_imx->pinctrl, i2c_imx->pinctrl_pins_gpio);
}
static void i2c_imx_unprepare_recovery(struct i2c_adapter *adap)
{
struct imx_i2c_struct *i2c_imx;
i2c_imx = container_of(adap, struct imx_i2c_struct, adapter);
pinctrl_select_state(i2c_imx->pinctrl, i2c_imx->pinctrl_pins_default);
}
/*
* We switch SCL and SDA to their GPIO function and do some bitbanging
* for bus recovery. These alternative pinmux settings can be
* described in the device tree by a separate pinctrl state "gpio". If
* this is missing this is not a big problem, the only implication is
* that we can't do bus recovery.
*/
static int i2c_imx_init_recovery_info(struct imx_i2c_struct *i2c_imx,
struct platform_device *pdev)
{
struct i2c_bus_recovery_info *rinfo = &i2c_imx->rinfo;
i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
if (!i2c_imx->pinctrl || IS_ERR(i2c_imx->pinctrl)) {
dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n");
return PTR_ERR(i2c_imx->pinctrl);
}
i2c_imx->pinctrl_pins_default = pinctrl_lookup_state(i2c_imx->pinctrl,
PINCTRL_STATE_DEFAULT);
i2c_imx->pinctrl_pins_gpio = pinctrl_lookup_state(i2c_imx->pinctrl,
"gpio");
rinfo->sda_gpiod = devm_gpiod_get(&pdev->dev, "sda", GPIOD_IN);
rinfo->scl_gpiod = devm_gpiod_get(&pdev->dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
if (PTR_ERR(rinfo->sda_gpiod) == -EPROBE_DEFER ||
PTR_ERR(rinfo->scl_gpiod) == -EPROBE_DEFER) {
return -EPROBE_DEFER;
} else if (IS_ERR(rinfo->sda_gpiod) ||
IS_ERR(rinfo->scl_gpiod) ||
IS_ERR(i2c_imx->pinctrl_pins_default) ||
IS_ERR(i2c_imx->pinctrl_pins_gpio)) {
dev_dbg(&pdev->dev, "recovery information incomplete\n");
return 0;
}
dev_dbg(&pdev->dev, "using scl%s for recovery\n",
rinfo->sda_gpiod ? ",sda" : "");
rinfo->prepare_recovery = i2c_imx_prepare_recovery;
rinfo->unprepare_recovery = i2c_imx_unprepare_recovery;
rinfo->recover_bus = i2c_generic_scl_recovery;
i2c_imx->adapter.bus_recovery_info = rinfo;
return 0;
}
static u32 i2c_imx_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
| I2C_FUNC_SMBUS_READ_BLOCK_DATA;
}
static const struct i2c_algorithm i2c_imx_algo = {
.master_xfer = i2c_imx_xfer,
.functionality = i2c_imx_func,
};
static int i2c_imx_probe(struct platform_device *pdev)
{
const struct of_device_id *of_id = of_match_device(i2c_imx_dt_ids,
&pdev->dev);
struct imx_i2c_struct *i2c_imx;
struct resource *res;
struct imxi2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
void __iomem *base;
int irq, ret;
dma_addr_t phy_addr;
dev_dbg(&pdev->dev, "<%s>\n", __func__);
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "can't get irq number\n");
return irq;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(base))
return PTR_ERR(base);
phy_addr = (dma_addr_t)res->start;
i2c_imx = devm_kzalloc(&pdev->dev, sizeof(*i2c_imx), GFP_KERNEL);
if (!i2c_imx)
return -ENOMEM;
if (of_id)
i2c_imx->hwdata = of_id->data;
else
i2c_imx->hwdata = (struct imx_i2c_hwdata *)
platform_get_device_id(pdev)->driver_data;
/* Setup i2c_imx driver structure */
strlcpy(i2c_imx->adapter.name, pdev->name, sizeof(i2c_imx->adapter.name));
i2c_imx->adapter.owner = THIS_MODULE;
i2c_imx->adapter.algo = &i2c_imx_algo;
i2c_imx->adapter.dev.parent = &pdev->dev;
i2c_imx->adapter.nr = pdev->id;
i2c_imx->adapter.dev.of_node = pdev->dev.of_node;
i2c_imx->base = base;
/* Get I2C clock */
i2c_imx->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(i2c_imx->clk)) {
dev_err(&pdev->dev, "can't get I2C clock\n");
return PTR_ERR(i2c_imx->clk);
}
ret = clk_prepare_enable(i2c_imx->clk);
if (ret) {
dev_err(&pdev->dev, "can't enable I2C clock, ret=%d\n", ret);
return ret;
}
/* Request IRQ */
ret = devm_request_irq(&pdev->dev, irq, i2c_imx_isr, IRQF_SHARED,
pdev->name, i2c_imx);
if (ret) {
dev_err(&pdev->dev, "can't claim irq %d\n", irq);
goto clk_disable;
}
/* Init queue */
init_waitqueue_head(&i2c_imx->queue);
/* Set up adapter data */
i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
/* Set up platform driver data */
platform_set_drvdata(pdev, i2c_imx);
pm_runtime_set_autosuspend_delay(&pdev->dev, I2C_PM_TIMEOUT);
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
ret = pm_runtime_get_sync(&pdev->dev);
if (ret < 0)
goto rpm_disable;
/* Set up clock divider */
i2c_imx->bitrate = IMX_I2C_BIT_RATE;
ret = of_property_read_u32(pdev->dev.of_node,
"clock-frequency", &i2c_imx->bitrate);
if (ret < 0 && pdata && pdata->bitrate)
i2c_imx->bitrate = pdata->bitrate;
i2c_imx->clk_change_nb.notifier_call = i2c_imx_clk_notifier_call;
clk_notifier_register(i2c_imx->clk, &i2c_imx->clk_change_nb);
i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk));
/* Set up chip registers to defaults */
imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
i2c_imx, IMX_I2C_I2CR);
imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
/* Init optional bus recovery function */
ret = i2c_imx_init_recovery_info(i2c_imx, pdev);
/* Give it another chance if pinctrl used is not ready yet */
if (ret == -EPROBE_DEFER)
goto clk_notifier_unregister;
/* Add I2C adapter */
ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
if (ret < 0)
goto clk_notifier_unregister;
pm_runtime_mark_last_busy(&pdev->dev);
pm_runtime_put_autosuspend(&pdev->dev);
dev_dbg(&i2c_imx->adapter.dev, "claimed irq %d\n", irq);
dev_dbg(&i2c_imx->adapter.dev, "device resources: %pR\n", res);
dev_dbg(&i2c_imx->adapter.dev, "adapter name: \"%s\"\n",
i2c_imx->adapter.name);
dev_info(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n");
/* Init DMA config if supported */
i2c_imx_dma_request(i2c_imx, phy_addr);
return 0; /* Return OK */
clk_notifier_unregister:
clk_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb);
rpm_disable:
pm_runtime_put_noidle(&pdev->dev);
pm_runtime_disable(&pdev->dev);
pm_runtime_set_suspended(&pdev->dev);
pm_runtime_dont_use_autosuspend(&pdev->dev);
clk_disable:
clk_disable_unprepare(i2c_imx->clk);
return ret;
}
static int i2c_imx_remove(struct platform_device *pdev)
{
struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
int ret;
ret = pm_runtime_get_sync(&pdev->dev);
if (ret < 0)
return ret;
/* remove adapter */
dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n");
i2c_del_adapter(&i2c_imx->adapter);
if (i2c_imx->dma)
i2c_imx_dma_free(i2c_imx);
/* setup chip registers to defaults */
imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR);
imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IFDR);
imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2CR);
imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2SR);
clk_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb);
clk_disable_unprepare(i2c_imx->clk);
pm_runtime_put_noidle(&pdev->dev);
pm_runtime_disable(&pdev->dev);
return 0;
}
#ifdef CONFIG_PM
static int i2c_imx_runtime_suspend(struct device *dev)
{
struct imx_i2c_struct *i2c_imx = dev_get_drvdata(dev);
clk_disable(i2c_imx->clk);
return 0;
}
static int i2c_imx_runtime_resume(struct device *dev)
{
struct imx_i2c_struct *i2c_imx = dev_get_drvdata(dev);
int ret;
ret = clk_enable(i2c_imx->clk);
if (ret)
dev_err(dev, "can't enable I2C clock, ret=%d\n", ret);
return ret;
}
static const struct dev_pm_ops i2c_imx_pm_ops = {
SET_RUNTIME_PM_OPS(i2c_imx_runtime_suspend,
i2c_imx_runtime_resume, NULL)
};
#define I2C_IMX_PM_OPS (&i2c_imx_pm_ops)
#else
#define I2C_IMX_PM_OPS NULL
#endif /* CONFIG_PM */
static struct platform_driver i2c_imx_driver = {
.probe = i2c_imx_probe,
.remove = i2c_imx_remove,
.driver = {
.name = DRIVER_NAME,
.pm = I2C_IMX_PM_OPS,
.of_match_table = i2c_imx_dt_ids,
},
.id_table = imx_i2c_devtype,
};
static int __init i2c_adap_imx_init(void)
{
return platform_driver_register(&i2c_imx_driver);
}
subsys_initcall(i2c_adap_imx_init);
static void __exit i2c_adap_imx_exit(void)
{
platform_driver_unregister(&i2c_imx_driver);
}
module_exit(i2c_adap_imx_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Darius Augulis");
MODULE_DESCRIPTION("I2C adapter driver for IMX I2C bus");
MODULE_ALIAS("platform:" DRIVER_NAME);
Reference in New Issue View Git Blame Copy Permalink