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i2c: designware: add i2c gpio recovery option 

This patch contains much input from Phil Reid and has been tested
on Intel/Altera Cyclone V SOC Hardware with Altera GPIO's for the
SCL and SDA GPIO's.

Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Tim Sander <tim@krieglstein.org>
Signed-off-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Tim Sander 2017-11-02 10:40:27 +08:00 committed by Wolfram Sang
parent 0326f9f801
commit ca382f5b38
3 changed files with 63 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/i2c/busses/i2c-designware-common.c
View File

@ -230,7 +230,11 @@ int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
if (timeout <= 0) {
dev_warn(dev->dev, "timeout waiting for bus ready\n");
return -ETIMEDOUT;
i2c_recover_bus(&dev->adapter);
if (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY)
return -ETIMEDOUT;
return 0;
}
timeout--;
usleep_range(1000, 1100);

1
drivers/i2c/busses/i2c-designware-core.h
View File

@ -286,6 +286,7 @@ struct dw_i2c_dev {
void (*disable_int)(struct dw_i2c_dev *dev);
int (*init)(struct dw_i2c_dev *dev);
int mode;
struct i2c_bus_recovery_info rinfo;
};
#define ACCESS_SWAP 0x00000001

57
drivers/i2c/busses/i2c-designware-master.c
View File

@ -25,11 +25,13 @@
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>
#include "i2c-designware-core.h"
@ -443,6 +445,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
if (!wait_for_completion_timeout(&dev->cmd_complete, adap->timeout)) {
dev_err(dev->dev, "controller timed out\n");
/* i2c_dw_init implicitly disables the adapter */
i2c_recover_bus(&dev->adapter);
i2c_dw_init_master(dev);
ret = -ETIMEDOUT;
goto done;
@ -613,6 +616,56 @@ static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
return IRQ_HANDLED;
}
static void i2c_dw_prepare_recovery(struct i2c_adapter *adap)
{
struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
i2c_dw_disable(dev);
reset_control_assert(dev->rst);
i2c_dw_prepare_clk(dev, false);
}
static void i2c_dw_unprepare_recovery(struct i2c_adapter *adap)
{
struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
i2c_dw_prepare_clk(dev, true);
reset_control_deassert(dev->rst);
i2c_dw_init_master(dev);
}
static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
{
struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
struct i2c_adapter *adap = &dev->adapter;
struct gpio_desc *gpio;
int r;
gpio = devm_gpiod_get(dev->dev, "scl", GPIOD_OUT_HIGH);
if (IS_ERR(gpio)) {
r = PTR_ERR(gpio);
if (r == -ENOENT)
return 0;
return r;
}
rinfo->scl_gpiod = gpio;
gpio = devm_gpiod_get_optional(dev->dev, "sda", GPIOD_IN);
if (IS_ERR(gpio))
return PTR_ERR(gpio);
rinfo->sda_gpiod = gpio;
rinfo->recover_bus = i2c_generic_scl_recovery;
rinfo->prepare_recovery = i2c_dw_prepare_recovery;
rinfo->unprepare_recovery = i2c_dw_unprepare_recovery;
adap->bus_recovery_info = rinfo;
dev_info(dev->dev, "running with gpio recovery mode! scl%s",
rinfo->sda_gpiod ? ",sda" : "");
return 0;
}
int i2c_dw_probe(struct dw_i2c_dev *dev)
{
struct i2c_adapter *adap = &dev->adapter;
@ -652,6 +705,10 @@ int i2c_dw_probe(struct dw_i2c_dev *dev)
return ret;
}
ret = i2c_dw_init_recovery_info(dev);
if (ret)
return ret;
/*
* Increment PM usage count during adapter registration in order to
* avoid possible spurious runtime suspend when adapter device is