| Message ID | 20200619141904.910889-3-codrin.ciubotariu@microchip.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | i2c: core: add generic GPIO bus recovery | expand |
On Fri, Jun 19, 2020 at 05:19:02PM +0300, Codrin Ciubotariu wrote: > Multiple I2C bus drivers use similar bindings to obtain information needed > for I2C recovery. For example, for platforms using device-tree, the > properties look something like this: > > &i2c { > ... > pinctrl-names = "default", "gpio"; > // or pinctrl-names = "default", "recovery"; > pinctrl-0 = <&pinctrl_i2c_default>; > pinctrl-1 = <&pinctrl_i2c_gpio>; > sda-gpios = <&pio 0 GPIO_ACTIVE_HIGH>; > scl-gpios = <&pio 1 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>; > ... > } > > For this reason, we can add this common initialization in the core. This > way, other I2C bus drivers will be able to support GPIO recovery just by > providing a pointer to platform's pinctrl and calling i2c_recover_bus() > when SDA is stuck low. > > Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com> Thanks, it looks a lot like what I had in mind! > --- > drivers/i2c/i2c-core-base.c | 119 ++++++++++++++++++++++++++++++++++++ > include/linux/i2c.h | 11 ++++ > 2 files changed, 130 insertions(+) > > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c > index d1f278f73011..4ee29fec4e93 100644 > --- a/drivers/i2c/i2c-core-base.c > +++ b/drivers/i2c/i2c-core-base.c > @@ -32,6 +32,7 @@ > #include <linux/of_device.h> > #include <linux/of.h> > #include <linux/of_irq.h> > +#include <linux/pinctrl/consumer.h> > #include <linux/pm_domain.h> > #include <linux/pm_runtime.h> > #include <linux/pm_wakeirq.h> > @@ -179,6 +180,8 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) > struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; > int i = 0, scl = 1, ret = 0; > > + if (bri->pinctrl) > + pinctrl_select_state(bri->pinctrl, bri->pins_gpio); I think this should come after 'prepare_recovery'. It may be that 'prepare_recovery' already needs to select the pinctrl state to avoid a glitch. In this version, there would be a glitch then. If we move it down, the doubled 'pinctrl_select_state' would be a noop then. > if (bri->prepare_recovery) > bri->prepare_recovery(adap); > > @@ -236,6 +239,8 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) > > if (bri->unprepare_recovery) > bri->unprepare_recovery(adap); > + if (bri->pinctrl) > + pinctrl_select_state(bri->pinctrl, bri->pins_default); Here it is OK and will still work with the PXA version which needs to select the state on its own. > > return ret; > } > @@ -251,6 +256,118 @@ int i2c_recover_bus(struct i2c_adapter *adap) > } > EXPORT_SYMBOL_GPL(i2c_recover_bus); > > +static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap) > +{ > + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; > + struct device *dev = &adap->dev; > + struct pinctrl *p = bri->pinctrl; > + > + /* > + * we can't change states without pinctrl, so remove the states if > + * available s/available/populated/ ? > + */ > + if (!p) { > + bri->pins_default = NULL; > + bri->pins_gpio = NULL; > + return; > + } > + > + if (!bri->pins_default) { > + bri->pins_default = pinctrl_lookup_state(p, > + PINCTRL_STATE_DEFAULT); > + if (IS_ERR(bri->pins_default)) { > + dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n"); > + bri->pins_default = NULL; > + > + goto cleanup_pinctrl; I'd leave out the goto here. It is OK to check both parameters, I think. > + } > + } > + if (!bri->pins_gpio) { > + bri->pins_gpio = pinctrl_lookup_state(p, "gpio"); > + if (IS_ERR(bri->pins_gpio)) > + bri->pins_gpio = pinctrl_lookup_state(p, "recovery"); > + > + if (IS_ERR(bri->pins_gpio)) { > + dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n"); > + bri->pins_gpio = NULL; > + > + goto cleanup_pinctrl; This goto is not needed... > + } > + } > + > +cleanup_pinctrl: ... and this label can go then. Also nicer to read, I'd say. > + /* for pinctrl state changes, we need all the information */ > + if (!bri->pins_default || !bri->pins_gpio) { > + bri->pinctrl = NULL; > + bri->pins_default = NULL; > + bri->pins_gpio = NULL; > + } else { > + dev_info(dev, "using pinctrl states for GPIO recovery"); > + } > +} > + > +static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap) > +{ > + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; > + struct device *dev = &adap->dev; > + struct gpio_desc *gpiod; > + int ret = 0; > + > + /* don't touch the recovery information if the driver is not using > + * generic SCL recovery > + */ Not kernel comment style. > + if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery) > + return 0; No need for the first condition. 'i2c_generic_scl_recovery' is definately not NULL :) > + > + /* > + * pins might be taken as GPIO, so we might as well inform pinctrl about s/might as well/should/ > + * this and move the state to GPIO > + */ > + if (bri->pinctrl) > + pinctrl_select_state(bri->pinctrl, bri->pins_gpio); > + > + /* > + * if there is incomplete or no recovery information, see if generic > + * GPIO recovery is available > + */ > + if (!bri->scl_gpiod) { > + gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN); > + if (PTR_ERR(gpiod) == -EPROBE_DEFER) { > + ret = -EPROBE_DEFER; > + goto cleanup_pinctrl_state; > + } > + if (!IS_ERR(gpiod)) { > + bri->scl_gpiod = gpiod; > + bri->recover_bus = i2c_generic_scl_recovery; > + dev_info(dev, "using generic GPIOs for recovery\n"); > + } > + } I think this extra code from the PXA driver makes sense in case SDA was released while we were executing this code: 1383 /* 1384 * We have SCL. Pull SCL low and wait a bit so that SDA glitches 1385 * have no effect. 1386 */ 1387 gpiod_direction_output(bri->scl_gpiod, 0); 1388 udelay(10); 1389 bri->sda_gpiod = devm_gpiod_get(dev, "sda", GPIOD_OUT_HIGH_OPEN_DRAIN); 1390 1391 /* Wait a bit in case of a SDA glitch, and then release SCL. */ 1392 udelay(10); 1393 gpiod_direction_output(bri->scl_gpiod, 1); > + > + /* SDA GPIOD line is optional, so we care about DEFER only */ > + if (!bri->sda_gpiod) { > + gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN); > + if (PTR_ERR(gpiod) == -EPROBE_DEFER) { > + ret = -EPROBE_DEFER; > + goto cleanup_pinctrl_state; > + } > + if (!IS_ERR(gpiod)) > + bri->sda_gpiod = gpiod; > + } > + > +cleanup_pinctrl_state: > + /* change the state of the pins back to their default state */ > + if (bri->pinctrl) > + pinctrl_select_state(bri->pinctrl, bri->pins_default); > + > + return ret; > +} > + Rest looks good! If you have some time for this now, I will make sure to get it into 5.9. With these minor things fixed, this is good to go, me thinks.
On 02.08.2020 19:54, Wolfram Sang wrote: > On Fri, Jun 19, 2020 at 05:19:02PM +0300, Codrin Ciubotariu wrote: >> Multiple I2C bus drivers use similar bindings to obtain information needed >> for I2C recovery. For example, for platforms using device-tree, the >> properties look something like this: >> >> &i2c { >> ... >> pinctrl-names = "default", "gpio"; >> // or pinctrl-names = "default", "recovery"; >> pinctrl-0 = <&pinctrl_i2c_default>; >> pinctrl-1 = <&pinctrl_i2c_gpio>; >> sda-gpios = <&pio 0 GPIO_ACTIVE_HIGH>; >> scl-gpios = <&pio 1 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>; >> ... >> } >> >> For this reason, we can add this common initialization in the core. This >> way, other I2C bus drivers will be able to support GPIO recovery just by >> providing a pointer to platform's pinctrl and calling i2c_recover_bus() >> when SDA is stuck low. >> >> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com> > > Thanks, it looks a lot like what I had in mind! > >> --- >> drivers/i2c/i2c-core-base.c | 119 ++++++++++++++++++++++++++++++++++++ >> include/linux/i2c.h | 11 ++++ >> 2 files changed, 130 insertions(+) >> >> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c >> index d1f278f73011..4ee29fec4e93 100644 >> --- a/drivers/i2c/i2c-core-base.c >> +++ b/drivers/i2c/i2c-core-base.c >> @@ -32,6 +32,7 @@ >> #include <linux/of_device.h> >> #include <linux/of.h> >> #include <linux/of_irq.h> >> +#include <linux/pinctrl/consumer.h> >> #include <linux/pm_domain.h> >> #include <linux/pm_runtime.h> >> #include <linux/pm_wakeirq.h> >> @@ -179,6 +180,8 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) >> struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; >> int i = 0, scl = 1, ret = 0; >> >> + if (bri->pinctrl) >> + pinctrl_select_state(bri->pinctrl, bri->pins_gpio); > > I think this should come after 'prepare_recovery'. It may be that > 'prepare_recovery' already needs to select the pinctrl state to avoid a > glitch. In this version, there would be a glitch then. If we move it > down, the doubled 'pinctrl_select_state' would be a noop then. Agree > >> if (bri->prepare_recovery) >> bri->prepare_recovery(adap); >> >> @@ -236,6 +239,8 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) >> >> if (bri->unprepare_recovery) >> bri->unprepare_recovery(adap); >> + if (bri->pinctrl) >> + pinctrl_select_state(bri->pinctrl, bri->pins_default); > > Here it is OK and will still work with the PXA version which needs to > select the state on its own. > >> >> return ret; >> } >> @@ -251,6 +256,118 @@ int i2c_recover_bus(struct i2c_adapter *adap) >> } >> EXPORT_SYMBOL_GPL(i2c_recover_bus); >> >> +static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap) >> +{ >> + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; >> + struct device *dev = &adap->dev; >> + struct pinctrl *p = bri->pinctrl; >> + >> + /* >> + * we can't change states without pinctrl, so remove the states if >> + * available > > s/available/populated/ ? OK > >> + */ >> + if (!p) { >> + bri->pins_default = NULL; >> + bri->pins_gpio = NULL; >> + return; >> + } >> + >> + if (!bri->pins_default) { >> + bri->pins_default = pinctrl_lookup_state(p, >> + PINCTRL_STATE_DEFAULT); >> + if (IS_ERR(bri->pins_default)) { >> + dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n"); >> + bri->pins_default = NULL; >> + >> + goto cleanup_pinctrl; > > I'd leave out the goto here. It is OK to check both parameters, I think. since default state is missing, the next check can be skipped, but I agree that removing the label makes things easier to read. > >> + } >> + } >> + if (!bri->pins_gpio) { >> + bri->pins_gpio = pinctrl_lookup_state(p, "gpio"); >> + if (IS_ERR(bri->pins_gpio)) >> + bri->pins_gpio = pinctrl_lookup_state(p, "recovery"); >> + >> + if (IS_ERR(bri->pins_gpio)) { >> + dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n"); >> + bri->pins_gpio = NULL; >> + >> + goto cleanup_pinctrl; > > This goto is not needed... right > >> + } >> + } >> + >> +cleanup_pinctrl: > > ... and this label can go then. Also nicer to read, I'd say. I will remove it. > >> + /* for pinctrl state changes, we need all the information */ >> + if (!bri->pins_default || !bri->pins_gpio) { >> + bri->pinctrl = NULL; >> + bri->pins_default = NULL; >> + bri->pins_gpio = NULL; >> + } else { >> + dev_info(dev, "using pinctrl states for GPIO recovery"); >> + } >> +} >> + >> +static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap) >> +{ >> + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; >> + struct device *dev = &adap->dev; >> + struct gpio_desc *gpiod; >> + int ret = 0; >> + >> + /* don't touch the recovery information if the driver is not using >> + * generic SCL recovery >> + */ > > Not kernel comment style. Right, sorry about this. Will fix. > >> + if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery) >> + return 0; > > No need for the first condition. 'i2c_generic_scl_recovery' is > definately not NULL :) It is not the same thing. Without the first check, it will return 0 if bri->recover_bus is NULL, which is not what we want. If bri->recover_bus is NULL (and the pintrl states and gpios are in place) we can set recover_bus to i2c_generic_scl_recovery and use the generic recovery. > >> + >> + /* >> + * pins might be taken as GPIO, so we might as well inform pinctrl about > > s/might as well/should/ OK > >> + * this and move the state to GPIO >> + */ >> + if (bri->pinctrl) >> + pinctrl_select_state(bri->pinctrl, bri->pins_gpio); >> + >> + /* >> + * if there is incomplete or no recovery information, see if generic >> + * GPIO recovery is available >> + */ >> + if (!bri->scl_gpiod) { >> + gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN); >> + if (PTR_ERR(gpiod) == -EPROBE_DEFER) { >> + ret = -EPROBE_DEFER; >> + goto cleanup_pinctrl_state; >> + } >> + if (!IS_ERR(gpiod)) { >> + bri->scl_gpiod = gpiod; >> + bri->recover_bus = i2c_generic_scl_recovery; >> + dev_info(dev, "using generic GPIOs for recovery\n"); >> + } >> + } > > I think this extra code from the PXA driver makes sense in case SDA was > released while we were executing this code: > > 1383 /* > 1384 * We have SCL. Pull SCL low and wait a bit so that SDA glitches > 1385 * have no effect. > 1386 */ > 1387 gpiod_direction_output(bri->scl_gpiod, 0); > 1388 udelay(10); > 1389 bri->sda_gpiod = devm_gpiod_get(dev, "sda", GPIOD_OUT_HIGH_OPEN_DRAIN); > 1390 > 1391 /* Wait a bit in case of a SDA glitch, and then release SCL. */ > 1392 udelay(10); > 1393 gpiod_direction_output(bri->scl_gpiod, 1); I agree. I will add it. > >> + >> + /* SDA GPIOD line is optional, so we care about DEFER only */ >> + if (!bri->sda_gpiod) { >> + gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN); >> + if (PTR_ERR(gpiod) == -EPROBE_DEFER) { >> + ret = -EPROBE_DEFER; >> + goto cleanup_pinctrl_state; >> + } >> + if (!IS_ERR(gpiod)) >> + bri->sda_gpiod = gpiod; >> + } >> + >> +cleanup_pinctrl_state: >> + /* change the state of the pins back to their default state */ >> + if (bri->pinctrl) >> + pinctrl_select_state(bri->pinctrl, bri->pins_default); >> + >> + return ret; >> +} >> + > > Rest looks good! If you have some time for this now, I will make sure to > get it into 5.9. With these minor things fixed, this is good to go, me > thinks. > I agree will all your suggestions, except with the removal of if (bri->recover_bus) . If you agree with this, I can send the next version and remove the RFC. Thanks and best regards, Codrin
> I agree will all your suggestions, except with the removal of if > (bri->recover_bus) . If you agree with this, I can send the next version > and remove the RFC. Yes, sure. That was a brown paper bag thingie from my side. Please go ahead!
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index d1f278f73011..4ee29fec4e93 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -32,6 +32,7 @@ #include <linux/of_device.h> #include <linux/of.h> #include <linux/of_irq.h> +#include <linux/pinctrl/consumer.h> #include <linux/pm_domain.h> #include <linux/pm_runtime.h> #include <linux/pm_wakeirq.h> @@ -179,6 +180,8 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; int i = 0, scl = 1, ret = 0; + if (bri->pinctrl) + pinctrl_select_state(bri->pinctrl, bri->pins_gpio); if (bri->prepare_recovery) bri->prepare_recovery(adap); @@ -236,6 +239,8 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) if (bri->unprepare_recovery) bri->unprepare_recovery(adap); + if (bri->pinctrl) + pinctrl_select_state(bri->pinctrl, bri->pins_default); return ret; } @@ -251,6 +256,118 @@ int i2c_recover_bus(struct i2c_adapter *adap) } EXPORT_SYMBOL_GPL(i2c_recover_bus); +static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap) +{ + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; + struct device *dev = &adap->dev; + struct pinctrl *p = bri->pinctrl; + + /* + * we can't change states without pinctrl, so remove the states if + * available + */ + if (!p) { + bri->pins_default = NULL; + bri->pins_gpio = NULL; + return; + } + + if (!bri->pins_default) { + bri->pins_default = pinctrl_lookup_state(p, + PINCTRL_STATE_DEFAULT); + if (IS_ERR(bri->pins_default)) { + dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n"); + bri->pins_default = NULL; + + goto cleanup_pinctrl; + } + } + if (!bri->pins_gpio) { + bri->pins_gpio = pinctrl_lookup_state(p, "gpio"); + if (IS_ERR(bri->pins_gpio)) + bri->pins_gpio = pinctrl_lookup_state(p, "recovery"); + + if (IS_ERR(bri->pins_gpio)) { + dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n"); + bri->pins_gpio = NULL; + + goto cleanup_pinctrl; + } + } + +cleanup_pinctrl: + /* for pinctrl state changes, we need all the information */ + if (!bri->pins_default || !bri->pins_gpio) { + bri->pinctrl = NULL; + bri->pins_default = NULL; + bri->pins_gpio = NULL; + } else { + dev_info(dev, "using pinctrl states for GPIO recovery"); + } +} + +static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap) +{ + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; + struct device *dev = &adap->dev; + struct gpio_desc *gpiod; + int ret = 0; + + /* don't touch the recovery information if the driver is not using + * generic SCL recovery + */ + if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery) + return 0; + + /* + * pins might be taken as GPIO, so we might as well inform pinctrl about + * this and move the state to GPIO + */ + if (bri->pinctrl) + pinctrl_select_state(bri->pinctrl, bri->pins_gpio); + + /* + * if there is incomplete or no recovery information, see if generic + * GPIO recovery is available + */ + if (!bri->scl_gpiod) { + gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN); + if (PTR_ERR(gpiod) == -EPROBE_DEFER) { + ret = -EPROBE_DEFER; + goto cleanup_pinctrl_state; + } + if (!IS_ERR(gpiod)) { + bri->scl_gpiod = gpiod; + bri->recover_bus = i2c_generic_scl_recovery; + dev_info(dev, "using generic GPIOs for recovery\n"); + } + } + + /* SDA GPIOD line is optional, so we care about DEFER only */ + if (!bri->sda_gpiod) { + gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN); + if (PTR_ERR(gpiod) == -EPROBE_DEFER) { + ret = -EPROBE_DEFER; + goto cleanup_pinctrl_state; + } + if (!IS_ERR(gpiod)) + bri->sda_gpiod = gpiod; + } + +cleanup_pinctrl_state: + /* change the state of the pins back to their default state */ + if (bri->pinctrl) + pinctrl_select_state(bri->pinctrl, bri->pins_default); + + return ret; +} + +static int i2c_gpio_init_recovery(struct i2c_adapter *adap) +{ + i2c_gpio_init_pinctrl_recovery(adap); + return i2c_gpio_init_generic_recovery(adap); +} + static void i2c_init_recovery(struct i2c_adapter *adap) { struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; @@ -259,6 +376,8 @@ static void i2c_init_recovery(struct i2c_adapter *adap) if (!bri) return; + i2c_gpio_init_recovery(adap); + if (!bri->recover_bus) { err_str = "no recover_bus() found"; goto err; diff --git a/include/linux/i2c.h b/include/linux/i2c.h index c10617bb980a..c62c9b48f719 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -611,6 +611,14 @@ struct i2c_timings { * may configure padmux here for SDA/SCL line or something else they want. * @scl_gpiod: gpiod of the SCL line. Only required for GPIO recovery. * @sda_gpiod: gpiod of the SDA line. Only required for GPIO recovery. + * @pinctrl: pinctrl used by GPIO recovery to change the state of the I2C pins. + * Optional. + * @pins_default: default state of SCL/SDA lines, when they are assigned to the + * I2C bus. Optional. Populated internally for GPIO recovery, if a state with + * the name PINCTRL_STATE_DEFAULT is found and pinctrl is valid. + * @pins_gpio: recovery state of SCL/SDA lines, when they are used as GPIOs. + * Optional. Populated internally for GPIO recovery, if this state is called + * "gpio" or "recovery" and pinctrl is valid. */ struct i2c_bus_recovery_info { int (*recover_bus)(struct i2c_adapter *adap); @@ -627,6 +635,9 @@ struct i2c_bus_recovery_info { /* gpio recovery */ struct gpio_desc *scl_gpiod; struct gpio_desc *sda_gpiod; + struct pinctrl *pinctrl; + struct pinctrl_state *pins_default; + struct pinctrl_state *pins_gpio; }; int i2c_recover_bus(struct i2c_adapter *adap);
Multiple I2C bus drivers use similar bindings to obtain information needed for I2C recovery. For example, for platforms using device-tree, the properties look something like this: &i2c { ... pinctrl-names = "default", "gpio"; // or pinctrl-names = "default", "recovery"; pinctrl-0 = <&pinctrl_i2c_default>; pinctrl-1 = <&pinctrl_i2c_gpio>; sda-gpios = <&pio 0 GPIO_ACTIVE_HIGH>; scl-gpios = <&pio 1 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>; ... } For this reason, we can add this common initialization in the core. This way, other I2C bus drivers will be able to support GPIO recovery just by providing a pointer to platform's pinctrl and calling i2c_recover_bus() when SDA is stuck low. Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com> --- drivers/i2c/i2c-core-base.c | 119 ++++++++++++++++++++++++++++++++++++ include/linux/i2c.h | 11 ++++ 2 files changed, 130 insertions(+)