| Message ID | 20200124181214.122950-1-marex@denx.de |
|---|---|
| State | New |
| Headers | show |
| Series | i2c: gpio: Add custom deblock sequence | expand |
Hello Marek, Am 24.01.2020 um 19:12 schrieb Marek Vasut: > Add custom deblock dequence for the I2C bus, needed on some devices. > This sequence is issued once, when probing the driver, and is controlled > by DT property, "i2c-gpio,deblock". > > Signed-off-by: Marek Vasut <marex at denx.de> > --- > drivers/i2c/i2c-gpio.c | 67 ++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 67 insertions(+) > > diff --git a/drivers/i2c/i2c-gpio.c b/drivers/i2c/i2c-gpio.c > index 4e8fa21473..46975ef5c8 100644 > --- a/drivers/i2c/i2c-gpio.c > +++ b/drivers/i2c/i2c-gpio.c > @@ -39,6 +39,11 @@ static int i2c_gpio_sda_get(struct gpio_desc *sda) > return dm_gpio_get_value(sda); > } > > +static int i2c_gpio_scl_get(struct gpio_desc *scl) > +{ > + return dm_gpio_get_value(scl); > +} > + > static void i2c_gpio_sda_set(struct gpio_desc *sda, int bit) > { > if (bit) > @@ -305,6 +310,67 @@ static int i2c_gpio_set_bus_speed(struct udevice *dev, unsigned int speed_hz) > return 0; > } > > +/* > + * I2C is a synchronous protocol and resets of the processor in the middle > + * of an access can block the I2C Bus until a powerdown of the full unit is > + * done. This function toggles the SCL until the SCL and SCA line are > + * released, but max. 16 times, after this a I2C start-sequence is sent. > + * This I2C Deblocking mechanism was developed by Keymile in association > + * with Anatech and Atmel in 1998. > + */ > +static void i2c_gpio_make_abort(struct udevice *dev) > +{ > + struct i2c_gpio_bus *bus = dev_get_priv(dev); > + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; > + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; > + int scl_state = 0; > + int sda_state = 0; > + int i = 0; > + int ret = 0; > + > +#define DELAY_ABORT_SEQ 62 /* @200kHz 9 clocks = 44us, 62us is ok */ > + > + i2c_gpio_scl_set(scl, 1); > + > + if (!i2c_gpio_sda_get(sda)) { > + ret = -1; > + for (i = 0; i < 16; i++) { > + i2c_gpio_scl_set(scl, 0); > + udelay(DELAY_ABORT_SEQ); > + i2c_gpio_scl_set(scl, 1); > + udelay(DELAY_ABORT_SEQ); > + scl_state = i2c_gpio_scl_get(scl); > + sda_state = i2c_gpio_sda_get(sda); > + if (scl_state && sda_state) { > + ret = 0; > + break; > + } > + } > + } > + > + if (!ret) { > + for (i = 0; i < 5; i++) { > + i2c_gpio_send_start(scl, sda, 2 * bus->udelay); > + i2c_gpio_scl_set(scl, 0); > + } > + } > + > + /* respect stop setup time */ > + udelay(DELAY_ABORT_SEQ); > + i2c_gpio_scl_set(scl, 1); > + udelay(DELAY_ABORT_SEQ); > + i2c_gpio_sda_set(sda, 1); > + i2c_gpio_sda_get(sda); > +} > + > +static int i2c_gpio_drv_probe(struct udevice *dev) > +{ > + if (dev_read_bool(dev, "i2c-gpio,deblock")) > + i2c_gpio_make_abort(dev); > + > + return 0; > +} > + > static int i2c_gpio_ofdata_to_platdata(struct udevice *dev) > { > struct i2c_gpio_bus *bus = dev_get_priv(dev); > @@ -341,6 +407,7 @@ U_BOOT_DRIVER(i2c_gpio) = { > .name = "i2c-gpio", > .id = UCLASS_I2C, > .of_match = i2c_gpio_ids, > + .probe = i2c_gpio_drv_probe, > .ofdata_to_platdata = i2c_gpio_ofdata_to_platdata, > .priv_auto_alloc_size = sizeof(struct i2c_gpio_bus), > .ops = &i2c_gpio_ops, > Hmm.. why do you add this into the probe function and do not add it to: https://gitlab.denx.de/u-boot/u-boot/blob/master/include/i2c.h#L382 which is called from: https://gitlab.denx.de/u-boot/u-boot/blob/master/drivers/i2c/i2c-uclass.c#L586 Ok, i2c_deblock() currently is only used from do_i2c_reset(), but may it is worth to adapt drivers/i2c-core/i2c-uclass.c to call the deblock sequence also from i2c_pre_probe()? May dependend on your proposed DT property "i2c-gpio,deblock" ? But please update also the documentation in u-boot:/doc/device-tree-bindings/i2c/i2c-gpio.txt or if we go the more generic way: u-boot:/doc/device-tree-bindings/i2c/i2c.txt Thanks! BTW: May it makes sense to adapt: https://gitlab.denx.de/u-boot/u-boot/blob/master/drivers/i2c/i2c-uclass.c#L504 too? bye, Heiko
On 1/27/20 7:40 AM, Heiko Schocher wrote: > Hello Marek, > > Am 24.01.2020 um 19:12 schrieb Marek Vasut: >> Add custom deblock dequence for the I2C bus, needed on some devices. >> This sequence is issued once, when probing the driver, and is controlled >> by DT property, "i2c-gpio,deblock". >> >> Signed-off-by: Marek Vasut <marex at denx.de> >> --- >> drivers/i2c/i2c-gpio.c | 67 ++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 67 insertions(+) >> >> diff --git a/drivers/i2c/i2c-gpio.c b/drivers/i2c/i2c-gpio.c >> index 4e8fa21473..46975ef5c8 100644 >> --- a/drivers/i2c/i2c-gpio.c >> +++ b/drivers/i2c/i2c-gpio.c >> @@ -39,6 +39,11 @@ static int i2c_gpio_sda_get(struct gpio_desc *sda) >> return dm_gpio_get_value(sda); >> } >> +static int i2c_gpio_scl_get(struct gpio_desc *scl) >> +{ >> + return dm_gpio_get_value(scl); >> +} >> + >> static void i2c_gpio_sda_set(struct gpio_desc *sda, int bit) >> { >> if (bit) >> @@ -305,6 +310,67 @@ static int i2c_gpio_set_bus_speed(struct udevice >> *dev, unsigned int speed_hz) >> return 0; >> } >> +/* >> + * I2C is a synchronous protocol and resets of the processor in the >> middle >> + * of an access can block the I2C Bus until a powerdown of the full >> unit is >> + * done. This function toggles the SCL until the SCL and SCA line are >> + * released, but max. 16 times, after this a I2C start-sequence is sent. >> + * This I2C Deblocking mechanism was developed by Keymile in association >> + * with Anatech and Atmel in 1998. >> + */ >> +static void i2c_gpio_make_abort(struct udevice *dev) >> +{ >> + struct i2c_gpio_bus *bus = dev_get_priv(dev); >> + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; >> + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; >> + int scl_state = 0; >> + int sda_state = 0; >> + int i = 0; >> + int ret = 0; >> + >> +#define DELAY_ABORT_SEQ 62 /* @200kHz 9 clocks = 44us, 62us is >> ok */ >> + >> + i2c_gpio_scl_set(scl, 1); >> + >> + if (!i2c_gpio_sda_get(sda)) { >> + ret = -1; >> + for (i = 0; i < 16; i++) { >> + i2c_gpio_scl_set(scl, 0); >> + udelay(DELAY_ABORT_SEQ); >> + i2c_gpio_scl_set(scl, 1); >> + udelay(DELAY_ABORT_SEQ); >> + scl_state = i2c_gpio_scl_get(scl); >> + sda_state = i2c_gpio_sda_get(sda); >> + if (scl_state && sda_state) { >> + ret = 0; >> + break; >> + } >> + } >> + } >> + >> + if (!ret) { >> + for (i = 0; i < 5; i++) { >> + i2c_gpio_send_start(scl, sda, 2 * bus->udelay); >> + i2c_gpio_scl_set(scl, 0); >> + } >> + } >> + >> + /* respect stop setup time */ >> + udelay(DELAY_ABORT_SEQ); >> + i2c_gpio_scl_set(scl, 1); >> + udelay(DELAY_ABORT_SEQ); >> + i2c_gpio_sda_set(sda, 1); >> + i2c_gpio_sda_get(sda); >> +} >> + >> +static int i2c_gpio_drv_probe(struct udevice *dev) >> +{ >> + if (dev_read_bool(dev, "i2c-gpio,deblock")) >> + i2c_gpio_make_abort(dev); >> + >> + return 0; >> +} >> + >> static int i2c_gpio_ofdata_to_platdata(struct udevice *dev) >> { >> struct i2c_gpio_bus *bus = dev_get_priv(dev); >> @@ -341,6 +407,7 @@ U_BOOT_DRIVER(i2c_gpio) = { >> .name = "i2c-gpio", >> .id = UCLASS_I2C, >> .of_match = i2c_gpio_ids, >> + .probe = i2c_gpio_drv_probe, >> .ofdata_to_platdata = i2c_gpio_ofdata_to_platdata, >> .priv_auto_alloc_size = sizeof(struct i2c_gpio_bus), >> .ops = &i2c_gpio_ops, >> > > Hmm.. why do you add this into the probe function and do not add > it to: > > https://gitlab.denx.de/u-boot/u-boot/blob/master/include/i2c.h#L382 Because I wasn't aware of this callback. > which is called from: > https://gitlab.denx.de/u-boot/u-boot/blob/master/drivers/i2c/i2c-uclass.c#L586 > > > > Ok, i2c_deblock() currently is only used from do_i2c_reset(), but may it > is worth to adapt drivers/i2c-core/i2c-uclass.c to call the deblock > sequence also from i2c_pre_probe()? > > May dependend on your proposed DT property "i2c-gpio,deblock" ? > > But please update also the documentation in > > u-boot:/doc/device-tree-bindings/i2c/i2c-gpio.txt > > or if we go the more generic way: > > u-boot:/doc/device-tree-bindings/i2c/i2c.txt > > Thanks! > > BTW: May it makes sense to adapt: > https://gitlab.denx.de/u-boot/u-boot/blob/master/drivers/i2c/i2c-uclass.c#L504 I need to take a look at this one.
diff --git a/drivers/i2c/i2c-gpio.c b/drivers/i2c/i2c-gpio.c index 4e8fa21473..46975ef5c8 100644 --- a/drivers/i2c/i2c-gpio.c +++ b/drivers/i2c/i2c-gpio.c @@ -39,6 +39,11 @@ static int i2c_gpio_sda_get(struct gpio_desc *sda) return dm_gpio_get_value(sda); } +static int i2c_gpio_scl_get(struct gpio_desc *scl) +{ + return dm_gpio_get_value(scl); +} + static void i2c_gpio_sda_set(struct gpio_desc *sda, int bit) { if (bit) @@ -305,6 +310,67 @@ static int i2c_gpio_set_bus_speed(struct udevice *dev, unsigned int speed_hz) return 0; } +/* + * I2C is a synchronous protocol and resets of the processor in the middle + * of an access can block the I2C Bus until a powerdown of the full unit is + * done. This function toggles the SCL until the SCL and SCA line are + * released, but max. 16 times, after this a I2C start-sequence is sent. + * This I2C Deblocking mechanism was developed by Keymile in association + * with Anatech and Atmel in 1998. + */ +static void i2c_gpio_make_abort(struct udevice *dev) +{ + struct i2c_gpio_bus *bus = dev_get_priv(dev); + struct gpio_desc *scl = &bus->gpios[PIN_SCL]; + struct gpio_desc *sda = &bus->gpios[PIN_SDA]; + int scl_state = 0; + int sda_state = 0; + int i = 0; + int ret = 0; + +#define DELAY_ABORT_SEQ 62 /* @200kHz 9 clocks = 44us, 62us is ok */ + + i2c_gpio_scl_set(scl, 1); + + if (!i2c_gpio_sda_get(sda)) { + ret = -1; + for (i = 0; i < 16; i++) { + i2c_gpio_scl_set(scl, 0); + udelay(DELAY_ABORT_SEQ); + i2c_gpio_scl_set(scl, 1); + udelay(DELAY_ABORT_SEQ); + scl_state = i2c_gpio_scl_get(scl); + sda_state = i2c_gpio_sda_get(sda); + if (scl_state && sda_state) { + ret = 0; + break; + } + } + } + + if (!ret) { + for (i = 0; i < 5; i++) { + i2c_gpio_send_start(scl, sda, 2 * bus->udelay); + i2c_gpio_scl_set(scl, 0); + } + } + + /* respect stop setup time */ + udelay(DELAY_ABORT_SEQ); + i2c_gpio_scl_set(scl, 1); + udelay(DELAY_ABORT_SEQ); + i2c_gpio_sda_set(sda, 1); + i2c_gpio_sda_get(sda); +} + +static int i2c_gpio_drv_probe(struct udevice *dev) +{ + if (dev_read_bool(dev, "i2c-gpio,deblock")) + i2c_gpio_make_abort(dev); + + return 0; +} + static int i2c_gpio_ofdata_to_platdata(struct udevice *dev) { struct i2c_gpio_bus *bus = dev_get_priv(dev); @@ -341,6 +407,7 @@ U_BOOT_DRIVER(i2c_gpio) = { .name = "i2c-gpio", .id = UCLASS_I2C, .of_match = i2c_gpio_ids, + .probe = i2c_gpio_drv_probe, .ofdata_to_platdata = i2c_gpio_ofdata_to_platdata, .priv_auto_alloc_size = sizeof(struct i2c_gpio_bus), .ops = &i2c_gpio_ops,
Add custom deblock dequence for the I2C bus, needed on some devices. This sequence is issued once, when probing the driver, and is controlled by DT property, "i2c-gpio,deblock". Signed-off-by: Marek Vasut <marex at denx.de> --- drivers/i2c/i2c-gpio.c | 67 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+)