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Commit 92526087 authored by Anirudh Ghayal's avatar Anirudh Ghayal Committed by Gerrit - the friendly Code Review server
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regulator: fan53555: Add i2c retry logic 



The i2c-core may perform a bus recovery procedure if
the I2C lines are stuck low. In such a case the client
is expected to retry its i2c transaction. Add a mechanism
to perform multiple delayed retries in case of a I2C
transaction failure.

CRs-Fixed: 715354
Change-Id: I7ef83f1a633ed80830e52e8ccd7bb36144900093
Signed-off-by: default avatarAnirudh Ghayal <aghayal@codeaurora.org>
parent 156ba172

drivers/regulator/fan53555.c

+68 −11
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <linux/slab.h>

#include <linux/regmap.h>

#include <linux/debugfs.h>

#include <linux/delay.h>

#include <linux/regulator/fan53555.h>



/* Voltage setting */
@@ -106,6 +107,62 @@ struct fan53555_device_info { 
	bool disable_suspend;

};



static int delay_array[] = {10, 20, 30, 40, 50};



static int fan53555_read(struct fan53555_device_info *di, unsigned int reg,

						unsigned int *val)

{

	int i = 0, rc = 0;



	rc = regmap_read(di->regmap, reg, val);

	for (i = 0; rc && i < ARRAY_SIZE(delay_array); i++) {

		pr_debug("Failed reading reg=%u - retry(%d)\n", reg, i);

		msleep(delay_array[i]);

		rc = regmap_read(di->regmap, reg, val);

	}



	if (rc)

		pr_err("Failed reading reg=%u rc=%d\n", reg, rc);



	return rc;

}



static int fan53555_write(struct fan53555_device_info *di, unsigned int reg,

						unsigned int val)

{

	int i = 0, rc = 0;



	rc = regmap_write(di->regmap, reg, val);

	for (i = 0; rc && i < ARRAY_SIZE(delay_array); i++) {

		pr_debug("Failed writing reg=%u - retry(%d)\n", reg, i);

		msleep(delay_array[i]);

		rc = regmap_write(di->regmap, reg, val);

	}



	if (rc)

		pr_err("Failed writing reg=%u rc=%d\n", reg, rc);



	return rc;

}



static int fan53555_update_bits(struct fan53555_device_info *di,

			unsigned int reg, unsigned int mask, unsigned int val)

{

	int i = 0, rc = 0;



	rc = regmap_update_bits(di->regmap, reg, mask, val);

	for (i = 0; rc && i < ARRAY_SIZE(delay_array); i++) {

		pr_debug("Failed updating reg=%u - retry(%d)\n", reg, i);

		msleep(delay_array[i]);

		rc = regmap_update_bits(di->regmap, reg, mask, val);

	}



	if (rc)

		pr_err("Failed updating reg=%u rc=%d\n", reg, rc);



	return rc;

}



static int fan53555_set_suspend_voltage(struct regulator_dev *rdev, int uV)

{

	struct fan53555_device_info *di = rdev_get_drvdata(rdev);
@@ -116,7 +173,7 @@ static int fan53555_set_suspend_voltage(struct regulator_dev *rdev, int uV) 
	ret = regulator_map_voltage_linear(rdev, uV, uV);

	if (ret < 0)

		return -EINVAL;

	ret = regmap_update_bits(di->regmap, di->sleep_reg,

	ret = fan53555_update_bits(di, di->sleep_reg,

					VSEL_NSEL_MASK, ret);

	if (ret < 0)

		return -EINVAL;
@@ -133,11 +190,11 @@ static int fan53555_set_mode(struct regulator_dev *rdev, unsigned int mode) 


	switch (mode) {

	case REGULATOR_MODE_FAST:

		regmap_update_bits(di->regmap, di->vol_reg,

		fan53555_update_bits(di, di->vol_reg,

				VSEL_MODE, VSEL_MODE);

		break;

	case REGULATOR_MODE_NORMAL:

		regmap_update_bits(di->regmap, di->vol_reg, VSEL_MODE, 0);

		fan53555_update_bits(di, di->vol_reg, VSEL_MODE, 0);

		break;

	default:

		return -EINVAL;
@@ -151,7 +208,7 @@ static unsigned int fan53555_get_mode(struct regulator_dev *rdev) 
	unsigned int val;

	int ret = 0;



	ret = regmap_read(di->regmap, di->vol_reg, &val);

	ret = fan53555_read(di, di->vol_reg, &val);

	if (ret < 0)

		return ret;

	if (val & VSEL_MODE)
@@ -280,7 +337,7 @@ static int fan53555_device_setup(struct fan53555_device_info *di, 
	reg = FAN53555_CONTROL;

	data = di->slew_rate << CTL_SLEW_SHIFT;

	mask = CTL_SLEW_MASK;

	return regmap_update_bits(di->regmap, reg, mask, data);

	return fan53555_update_bits(di, reg, mask, data);

}



static int fan53555_regulator_register(struct fan53555_device_info *di,
@@ -383,7 +440,7 @@ static int fan53555_restore_working_reg(struct device_node *node, 
	u32 val;



	/* Restore register from back up register */

	ret = regmap_read(di->regmap, di->sleep_reg, &val);

	ret = fan53555_read(di, di->sleep_reg, &val);

	if (ret < 0) {

		dev_err(di->dev,

			"Failed to get backup data from reg %d, ret = %d\n",
@@ -391,7 +448,7 @@ static int fan53555_restore_working_reg(struct device_node *node, 
		return ret;

	}



	ret = regmap_update_bits(di->regmap,

	ret = fan53555_update_bits(di,

		di->vol_reg, VSEL_FULL_MASK, val);

	if (ret < 0) {

		dev_err(di->dev,
@@ -456,7 +513,7 @@ static int get_reg(void *data, u64 *val) 
	int rc;

	unsigned int temp = 0;



	rc = regmap_read(di->regmap, di->peek_poke_address, &temp);

	rc = fan53555_read(di, di->peek_poke_address, &temp);

	if (rc < 0)

		dev_err(di->dev, "Couldn't read reg %x rc = %d\n",

				di->peek_poke_address, rc);
@@ -473,7 +530,7 @@ static int set_reg(void *data, u64 val) 
	unsigned int temp = 0;



	temp = (unsigned int) val;

	rc = regmap_write(di->regmap, di->peek_poke_address, temp);

	rc = fan53555_write(di, di->peek_poke_address, temp);

	if (rc < 0)

		dev_err(di->dev, "Couldn't write 0x%02x to 0x%02x rc= %d\n",

			di->peek_poke_address, temp, rc);
@@ -516,14 +573,14 @@ static int fan53555_regulator_probe(struct i2c_client *client, 
	di->regulator = pdata->regulator;

	i2c_set_clientdata(client, di);

	/* Get chip ID */

	ret = regmap_read(di->regmap, FAN53555_ID1, &val);

	ret = fan53555_read(di, FAN53555_ID1, &val);

	if (ret < 0) {

		dev_err(&client->dev, "Failed to get chip ID!\n");

		return -ENODEV;

	}

	di->chip_id = val & DIE_ID;

	/* Get chip revision */

	ret = regmap_read(di->regmap, FAN53555_ID2, &val);

	ret = fan53555_read(di, FAN53555_ID2, &val);

	if (ret < 0) {

		dev_err(&client->dev, "Failed to get chip Rev!\n");

		return -ENODEV;