From patchwork Fri Feb 7 15:57:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 236046 List-Id: U-Boot discussion From: marex at denx.de (Marek Vasut) Date: Fri, 7 Feb 2020 16:57:49 +0100 Subject: [PATCH 1/4] i2c: Make deblock delay and SCL clock configurable Message-ID: <20200207155752.40930-1-marex@denx.de> Make the delay between SCL line changes and the number of SCL clock changes configurable as a parameter of the deblock function. No functional change. Signed-off-by: Marek Vasut Reviewed-by: Heiko Schocher --- drivers/i2c/i2c-uclass.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c index 2aa3efe8aa..25af1fabdb 100644 --- a/drivers/i2c/i2c-uclass.c +++ b/drivers/i2c/i2c-uclass.c @@ -502,34 +502,35 @@ static int i2c_gpio_get_pin(struct gpio_desc *pin) } static int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin, - struct gpio_desc *scl_pin) + struct gpio_desc *scl_pin, + unsigned int scl_count, + unsigned int delay) { - int counter = 9; int ret = 0; i2c_gpio_set_pin(sda_pin, 1); i2c_gpio_set_pin(scl_pin, 1); - udelay(5); + udelay(delay); /* Toggle SCL until slave release SDA */ - while (counter-- >= 0) { + while (scl_count-- >= 0) { i2c_gpio_set_pin(scl_pin, 1); - udelay(5); + udelay(delay); i2c_gpio_set_pin(scl_pin, 0); - udelay(5); + udelay(delay); if (i2c_gpio_get_pin(sda_pin)) break; } /* Then, send I2C stop */ i2c_gpio_set_pin(sda_pin, 0); - udelay(5); + udelay(delay); i2c_gpio_set_pin(scl_pin, 1); - udelay(5); + udelay(delay); i2c_gpio_set_pin(sda_pin, 1); - udelay(5); + udelay(delay); if (!i2c_gpio_get_pin(sda_pin) || !i2c_gpio_get_pin(scl_pin)) ret = -EREMOTEIO; @@ -561,7 +562,7 @@ static int i2c_deblock_gpio(struct udevice *bus) goto out_no_pinctrl; } - ret0 = i2c_deblock_gpio_loop(&gpios[PIN_SDA], &gpios[PIN_SCL]); + ret0 = i2c_deblock_gpio_loop(&gpios[PIN_SDA], &gpios[PIN_SCL], 9, 5); ret = pinctrl_select_state(bus, "default"); if (ret) { From patchwork Fri Feb 7 15:57:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 236047 List-Id: U-Boot discussion From: marex at denx.de (Marek Vasut) Date: Fri, 7 Feb 2020 16:57:50 +0100 Subject: [PATCH 2/4] i2c: Export i2c_deblock_gpio_loop() In-Reply-To: <20200207155752.40930-1-marex@denx.de> References: <20200207155752.40930-1-marex@denx.de> Message-ID: <20200207155752.40930-2-marex@denx.de> Export the i2c_deblock_gpio_loop() so it can be used in other places in U-Boot. In particular, this is useful in the GPIO I2C driver, which claims the SDA/SCL GPIOs and thus prevents the i2c_deblock() implementation from claiming the pins as GPIOs again. Signed-off-by: Marek Vasut Reviewed-by: Heiko Schocher --- drivers/i2c/i2c-uclass.c | 8 ++++---- include/i2c.h | 16 ++++++++++++++++ 2 files changed, 20 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c index 25af1fabdb..86f529241f 100644 --- a/drivers/i2c/i2c-uclass.c +++ b/drivers/i2c/i2c-uclass.c @@ -501,10 +501,10 @@ static int i2c_gpio_get_pin(struct gpio_desc *pin) return dm_gpio_get_value(pin); } -static int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin, - struct gpio_desc *scl_pin, - unsigned int scl_count, - unsigned int delay) +int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin, + struct gpio_desc *scl_pin, + unsigned int scl_count, + unsigned int delay) { int ret = 0; diff --git a/include/i2c.h b/include/i2c.h index 0faf8542e2..7c92042c58 100644 --- a/include/i2c.h +++ b/include/i2c.h @@ -330,6 +330,22 @@ uint i2c_get_chip_addr_offset_mask(struct udevice *dev); */ int i2c_deblock(struct udevice *bus); +/** + * i2c_deblock_gpio_loop() - recover a bus from an unknown state by toggling SDA/SCL + * + * This is the inner logic used for toggling I2C SDA/SCL lines as GPIOs + * for deblocking the I2C bus. + * + * @sda_pin: SDA GPIO + * @scl_pin: SCL GPIO + * @scl_count: Number of SCL clock cycles generated to deblock SDA + * @delay: Delay between SCL clock line changes + * @return 0 if OK, -ve on error + */ +struct gpio_desc; +int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin, struct gpio_desc *scl_pin, + unsigned int scl_count, unsigned int delay); + /** * struct dm_i2c_ops - driver operations for I2C uclass * From patchwork Fri Feb 7 15:57:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 236048 List-Id: U-Boot discussion From: marex at denx.de (Marek Vasut) Date: Fri, 7 Feb 2020 16:57:51 +0100 Subject: [PATCH 3/4] i2c: Add option to send start condition after deblocking In-Reply-To: <20200207155752.40930-1-marex@denx.de> References: <20200207155752.40930-1-marex@denx.de> Message-ID: <20200207155752.40930-3-marex@denx.de> Add option to send start condition after deblocking SDA. Signed-off-by: Marek Vasut Reviewed-by: Heiko Schocher --- drivers/i2c/i2c-uclass.c | 23 ++++++++++++++++++++--- include/i2c.h | 4 +++- 2 files changed, 23 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c index 86f529241f..e9ec388576 100644 --- a/drivers/i2c/i2c-uclass.c +++ b/drivers/i2c/i2c-uclass.c @@ -504,9 +504,10 @@ static int i2c_gpio_get_pin(struct gpio_desc *pin) int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin, struct gpio_desc *scl_pin, unsigned int scl_count, + unsigned int start_count, unsigned int delay) { - int ret = 0; + int i, ret = -EREMOTEIO; i2c_gpio_set_pin(sda_pin, 1); i2c_gpio_set_pin(scl_pin, 1); @@ -518,8 +519,24 @@ int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin, udelay(delay); i2c_gpio_set_pin(scl_pin, 0); udelay(delay); - if (i2c_gpio_get_pin(sda_pin)) + if (i2c_gpio_get_pin(sda_pin)) { + ret = 0; break; + } + } + + if (!ret && start_count) { + for (i = 0; i < start_count; i++) { + /* Send start condition */ + udelay(delay); + i2c_gpio_set_pin(sda_pin, 1); + udelay(delay); + i2c_gpio_set_pin(scl_pin, 1); + udelay(delay); + i2c_gpio_set_pin(sda_pin, 0); + udelay(delay); + i2c_gpio_set_pin(scl_pin, 0); + } } /* Then, send I2C stop */ @@ -562,7 +579,7 @@ static int i2c_deblock_gpio(struct udevice *bus) goto out_no_pinctrl; } - ret0 = i2c_deblock_gpio_loop(&gpios[PIN_SDA], &gpios[PIN_SCL], 9, 5); + ret0 = i2c_deblock_gpio_loop(&gpios[PIN_SDA], &gpios[PIN_SCL], 9, 0, 5); ret = pinctrl_select_state(bus, "default"); if (ret) { diff --git a/include/i2c.h b/include/i2c.h index 7c92042c58..059200115a 100644 --- a/include/i2c.h +++ b/include/i2c.h @@ -339,12 +339,14 @@ int i2c_deblock(struct udevice *bus); * @sda_pin: SDA GPIO * @scl_pin: SCL GPIO * @scl_count: Number of SCL clock cycles generated to deblock SDA + * @start_count:Number of I2C start conditions sent after deblocking SDA * @delay: Delay between SCL clock line changes * @return 0 if OK, -ve on error */ struct gpio_desc; int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin, struct gpio_desc *scl_pin, - unsigned int scl_count, unsigned int delay); + unsigned int scl_count, unsigned int start_count, + unsigned int delay); /** * struct dm_i2c_ops - driver operations for I2C uclass From patchwork Fri Feb 7 15:57:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 236049 List-Id: U-Boot discussion From: marex at denx.de (Marek Vasut) Date: Fri, 7 Feb 2020 16:57:52 +0100 Subject: [PATCH 4/4] i2c: gpio: Run deblock sequence on probe In-Reply-To: <20200207155752.40930-1-marex@denx.de> References: <20200207155752.40930-1-marex@denx.de> Message-ID: <20200207155752.40930-4-marex@denx.de> Add 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 Reviewed-by: Heiko Schocher --- drivers/i2c/i2c-gpio.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/i2c/i2c-gpio.c b/drivers/i2c/i2c-gpio.c index 4e8fa21473..b6b6ba9ee8 100644 --- a/drivers/i2c/i2c-gpio.c +++ b/drivers/i2c/i2c-gpio.c @@ -305,6 +305,20 @@ static int i2c_gpio_set_bus_speed(struct udevice *dev, unsigned int speed_hz) return 0; } +static int i2c_gpio_drv_probe(struct udevice *dev) +{ + if (dev_read_bool(dev, "i2c-gpio,deblock")) { + /* @200kHz 9 clocks = 44us, 62us is ok */ + const unsigned int DELAY_ABORT_SEQ = 62; + struct i2c_gpio_bus *bus = dev_get_priv(dev); + return i2c_deblock_gpio_loop(&bus->gpios[PIN_SDA], + &bus->gpios[PIN_SCL], + 16, 5, DELAY_ABORT_SEQ); + } + + return 0; +} + static int i2c_gpio_ofdata_to_platdata(struct udevice *dev) { struct i2c_gpio_bus *bus = dev_get_priv(dev); @@ -341,6 +355,7 @@ 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,