Commit 2330b05c authored by Ivaylo Dimitrov's avatar Ivaylo Dimitrov Committed by Mark Brown
Browse files

regulator: twl: Make sure we have access to powerbus before trying to write to it 



According to the TRM, we need to enable i2c access to powerbus before
writing to it. Also, a new write to powerbus should not be attempted if
there is a pending transfer. The current code does not implement that
functionality and while there are no known problems caused by that, it is
better to follow what TRM says.

Signed-off-by: default avatarIvaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent f55532a0

drivers/regulator/twl-regulator.c

+70 −8
Original line number Diff line number Diff line
@@ -21,7 +21,7 @@ 
#include <linux/regulator/machine.h>

#include <linux/regulator/of_regulator.h>

#include <linux/i2c/twl.h>



#include <linux/delay.h>



/*

 * The TWL4030/TW5030/TPS659x0/TWL6030 family chips include power management, a
@@ -188,6 +188,74 @@ static int twl6030reg_is_enabled(struct regulator_dev *rdev) 
	return grp && (val == TWL6030_CFG_STATE_ON);

}



#define PB_I2C_BUSY	BIT(0)

#define PB_I2C_BWEN	BIT(1)



/* Wait until buffer empty/ready to send a word on power bus. */

static int twl4030_wait_pb_ready(void)

{



	int	ret;

	int	timeout = 10;

	u8	val;



	do {

		ret = twl_i2c_read_u8(TWL_MODULE_PM_MASTER, &val,

				      TWL4030_PM_MASTER_PB_CFG);

		if (ret < 0)

			return ret;



		if (!(val & PB_I2C_BUSY))

			return 0;



		mdelay(1);

		timeout--;

	} while (timeout);



	return -ETIMEDOUT;

}



/* Send a word over the powerbus */

static int twl4030_send_pb_msg(unsigned msg)

{

	u8	val;

	int	ret;



	/* save powerbus configuration */

	ret = twl_i2c_read_u8(TWL_MODULE_PM_MASTER, &val,

			      TWL4030_PM_MASTER_PB_CFG);

	if (ret < 0)

		return ret;



	/* Enable i2c access to powerbus */

	ret = twl_i2c_write_u8(TWL_MODULE_PM_MASTER, val | PB_I2C_BWEN,

			       TWL4030_PM_MASTER_PB_CFG);

	if (ret < 0)

		return ret;



	ret = twl4030_wait_pb_ready();

	if (ret < 0)

		return ret;



	ret = twl_i2c_write_u8(TWL_MODULE_PM_MASTER, msg >> 8,

			       TWL4030_PM_MASTER_PB_WORD_MSB);

	if (ret < 0)

		return ret;



	ret = twl_i2c_write_u8(TWL_MODULE_PM_MASTER, msg & 0xff,

			       TWL4030_PM_MASTER_PB_WORD_LSB);

	if (ret < 0)

		return ret;



	ret = twl4030_wait_pb_ready();

	if (ret < 0)

		return ret;



	/* Restore powerbus configuration */

	return twl_i2c_write_u8(TWL_MODULE_PM_MASTER, val,

				TWL_MODULE_PM_MASTER);

}



static int twl4030reg_enable(struct regulator_dev *rdev)

{

	struct twlreg_info	*info = rdev_get_drvdata(rdev);
@@ -324,13 +392,7 @@ static int twl4030reg_set_mode(struct regulator_dev *rdev, unsigned mode) 
	if (!(status & (P3_GRP_4030 | P2_GRP_4030 | P1_GRP_4030)))

		return -EACCES;



	status = twl_i2c_write_u8(TWL_MODULE_PM_MASTER,

			message >> 8, TWL4030_PM_MASTER_PB_WORD_MSB);

	if (status < 0)

		return status;



	return twl_i2c_write_u8(TWL_MODULE_PM_MASTER,

			message & 0xff, TWL4030_PM_MASTER_PB_WORD_LSB);

	return twl4030_send_pb_msg(message);

}



static int twl6030reg_set_mode(struct regulator_dev *rdev, unsigned mode)

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