| Message ID | 1458980895-10240-2-git-send-email-ivo.g.dimitrov.75@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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.75@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 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi! > 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> > --- > 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; > + Can we do this plain while (timeout--) { }... ? Also... if the bit is not immediately available, it will wait for 1msec. Would it make sense to have timeout = 1000 but wait only 10usec each time or something? Thanks, Pavel > + 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; > +}
Hi, On 24.04.2016 19:10, Pavel Machek wrote: > Hi! > >> 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> >> --- >> 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; >> + > > Can we do this plain > > while (timeout--) { > }... > Now looking at the code, yes, while(timeout--) looks prettier, but as the $subject patch is in the linux-next for a couple of weeks already, that change will need another patch. I'll put that in my TODO, right after the RFC for the N900 cameras :) . > ? Also... if the bit is not immediately available, it will wait for > 1msec. Would it make sense to have timeout = 1000 but wait only 10usec > each time or something? > Well, anyway these look like a kind of arbitrary values, I guess it will work both ways. But, I borrowed the code in the patch from stock Nokia kernel, it has been field tested on tens of thousands of devices, so, unless you have hard values giving a reason to do it the other way, I prefer to keep it as it is. Regards, Ivo >> + 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; >> +} > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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); +} + 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)
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> --- drivers/regulator/twl-regulator.c | 78 +++++++++++++++++++++++++++++++++++---- 1 file changed, 70 insertions(+), 8 deletions(-)