On 26.03.2016 10:28, Ivaylo Dimitrov wrote:
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...@gmail.com>
---
drivers/regulator/twl-regulator.c | 78 +++++++++++++++++++++++++++++++++++----
1 file changed, 70 insertions(+), 8 deletions(-)
diff --git a/drivers/regulator/twl-regulator.c
b/drivers/regulator/twl-regulator.c
index 955a6fb..aad748b0 100644
--- a/drivers/regulator/twl-regulator.c
+++ b/drivers/regulator/twl-regulator.c
@@ -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);
Hmm, I made a copy/paste error here, this should be:
return twl_i2c_write_u8(TWL_MODULE_PM_MASTER, val,
TWL4030_PM_MASTER_PB_CFG);
Will send a new version of the patch.
+}
+
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)
Ivo
