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i2c: fsl: Add bus recovery support 

Useful for recovering busses. This needs additional device tree properties
describing the sda/scl gpios. The corresponding linux patch with the binding
description is currently under review.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Sascha Hauer 2015-09-17 09:56:14 +02:00
parent b654946ebc
commit e79fa9b5f0
1 changed files with 62 additions and 5 deletions
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67
drivers/i2c/busses/i2c-imx.c
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@ -35,11 +35,14 @@
#include <driver.h>
#include <init.h>
#include <of.h>
#include <gpio.h>
#include <malloc.h>
#include <types.h>
#include <xfuncs.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <pinctrl.h>
#include <of_gpio.h>
#include <io.h>
#include <i2c/i2c.h>
@ -108,6 +111,7 @@ struct fsl_i2c_struct {
int stopped;
unsigned int ifdr; /* FSL_I2C_IFDR */
unsigned int dfsrr; /* FSL_I2C_DFSRR */
struct i2c_bus_recovery_info rinfo;
};
#define to_fsl_i2c_struct(a) container_of(a, struct fsl_i2c_struct, adapter)
@ -232,8 +236,12 @@ static int i2c_fsl_start(struct i2c_adapter *adapter)
writeb(temp, base + FSL_I2C_I2CR);
result = i2c_fsl_bus_busy(adapter, 1);
if (result)
return result;
if (result) {
result = i2c_recover_bus(&i2c_fsl->adapter);
if (result)
return result;
return -EAGAIN;
}
i2c_fsl->stopped = 0;
@ -494,9 +502,14 @@ static int i2c_fsl_xfer(struct i2c_adapter *adapter,
int result;
/* Start I2C transfer */
result = i2c_fsl_start(adapter);
if (result)
goto fail0;
for (i = 0; i < 3; i++) {
result = i2c_fsl_start(adapter);
if (!result)
break;
if (result == -EAGAIN)
continue;
return result;
}
/* read/write data */
for (i = 0; i < num; i++) {
@ -527,6 +540,48 @@ fail0:
return (result < 0) ? result : num;
}
static void i2c_fsl_prepare_recovery(struct i2c_adapter *adapter)
{
int ret;
ret = pinctrl_select_state(adapter->dev.parent, "gpio");
if (ret)
dev_err(adapter->dev.parent, "pinctrl failed: %s\n", strerror(-ret));
}
static void i2c_fsl_unprepare_recovery(struct i2c_adapter *adapter)
{
int ret;
ret = pinctrl_select_state(adapter->dev.parent, "default");
if (ret)
dev_err(adapter->dev.parent, "pinctrl failed: %s\n", strerror(-ret));
}
static void i2c_fsl_init_recovery(struct fsl_i2c_struct *i2c_fsl, struct device_d *dev)
{
if (!dev->device_node)
return;
i2c_fsl->rinfo.sda_gpio = of_get_named_gpio_flags(dev->device_node,
"sda-gpios", 0, NULL);
i2c_fsl->rinfo.scl_gpio = of_get_named_gpio_flags(dev->device_node,
"scl-gpios", 0, NULL);
if (!gpio_is_valid(i2c_fsl->rinfo.sda_gpio) ||
!gpio_is_valid(i2c_fsl->rinfo.scl_gpio))
return;
i2c_fsl->rinfo.get_scl = i2c_get_scl_gpio_value;
i2c_fsl->rinfo.get_sda = i2c_get_sda_gpio_value;
i2c_fsl->rinfo.set_scl = i2c_set_scl_gpio_value;
i2c_fsl->rinfo.prepare_recovery = i2c_fsl_prepare_recovery;
i2c_fsl->rinfo.unprepare_recovery = i2c_fsl_unprepare_recovery;
i2c_fsl->rinfo.recover_bus = i2c_generic_gpio_recovery;
i2c_fsl->adapter.bus_recovery_info = &i2c_fsl->rinfo;
dev_dbg(dev, "initialized recovery info\n");
}
static int __init i2c_fsl_probe(struct device_d *pdev)
{
struct fsl_i2c_struct *i2c_fsl;
@ -555,6 +610,8 @@ static int __init i2c_fsl_probe(struct device_d *pdev)
goto fail;
}
i2c_fsl_init_recovery(i2c_fsl, pdev);
i2c_fsl->dfsrr = -1;
/* Set up clock divider */