redonkable/remarkable-linux
redonkable/remarkable-linux
1
0
Fork 0
Code Releases Activity

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

Browse source 
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: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Ivaylo Dimitrov 2016-03-26 10:28:13 +02:00 committed by Mark Brown
parent f55532a0c0
commit 2330b05c09
1 changed files with 70 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

78
drivers/regulator/twl-regulator.c
View file

@ -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)