| Message ID | 20220616141230.858409-1-dinguyen@kernel.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [PATCHv5,1/2] i2c: designware: introduce a custom scl recovery for SoCFPGA platforms | expand |
Hi On 6/16/22 17:12, Dinh Nguyen wrote: > The I2C pins on the SoCFPGA platforms do not go through a GPIO module, > thus cannot be recovered by the default method of by doing a GPIO access. > Only a reset of the I2C IP block can a recovery be successful. > One thing what is unclear to me how does this release the I2C slave that potentially keeps the SDA stuck low. Does platform specific reset sequence send 9 SCL pulses, toggle HW reset of the clients or cycle power of them? If recovery is only controller point of view then worth to emphasis it in the commit log and perhaps add a comment too into i2c_socfpga_scl_recovery(). Some might hit an issue that I2C client is stuck and wonder why recovery won't work. > The assignment of the recover_bus needs to get done before the call to > devm_gpiod_get_optional(), otherwise, the assignment is not taking place > because of an error after returning from devm_gpiod_get_optional(). > This sentence no longer true after v3? Otherwise code looks good to me. Jarkko
On 6/17/22 07:59, Jarkko Nikula wrote: > Hi > > On 6/16/22 17:12, Dinh Nguyen wrote: >> The I2C pins on the SoCFPGA platforms do not go through a GPIO module, >> thus cannot be recovered by the default method of by doing a GPIO access. >> Only a reset of the I2C IP block can a recovery be successful. >> > One thing what is unclear to me how does this release the I2C slave that > potentially keeps the SDA stuck low. Does platform specific reset > sequence send 9 SCL pulses, toggle HW reset of the clients or cycle > power of them? > > If recovery is only controller point of view then worth to emphasis it > in the commit log and perhaps add a comment too into > i2c_socfpga_scl_recovery(). Some might hit an issue that I2C client is > stuck and wonder why recovery won't work. The recovery is only resetting the controller itself and not the client. I'll add a comment in v6 to highlight this. > >> The assignment of the recover_bus needs to get done before the call to >> devm_gpiod_get_optional(), otherwise, the assignment is not taking place >> because of an error after returning from devm_gpiod_get_optional(). >> > This sentence no longer true after v3? Correct...will update. Dinh
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h index 70b80e710990..7b22ec1d6a96 100644 --- a/drivers/i2c/busses/i2c-designware-core.h +++ b/drivers/i2c/busses/i2c-designware-core.h @@ -303,6 +303,7 @@ struct dw_i2c_dev { #define MODEL_MSCC_OCELOT BIT(8) #define MODEL_BAIKAL_BT1 BIT(9) #define MODEL_AMD_NAVI_GPU BIT(10) +#define MODEL_SOCFPGA BIT(11) #define MODEL_MASK GENMASK(11, 8) /* diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c index 44a94b225ed8..fa2ea162acbd 100644 --- a/drivers/i2c/busses/i2c-designware-master.c +++ b/drivers/i2c/busses/i2c-designware-master.c @@ -813,10 +813,26 @@ static void i2c_dw_unprepare_recovery(struct i2c_adapter *adap) i2c_dw_init_master(dev); } -static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev) +static int i2c_socfpga_scl_recovery(struct i2c_adapter *adap) +{ + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; + + bri->prepare_recovery(adap); + bri->unprepare_recovery(adap); + + return 0; +} + +static int i2c_dw_init_socfpga_recovery_info(struct dw_i2c_dev *dev, + struct i2c_bus_recovery_info *rinfo) +{ + rinfo->recover_bus = i2c_socfpga_scl_recovery; + return 1; +} + +static int i2c_dw_init_generic_recovery_info(struct dw_i2c_dev *dev, + struct i2c_bus_recovery_info *rinfo) { - struct i2c_bus_recovery_info *rinfo = &dev->rinfo; - struct i2c_adapter *adap = &dev->adapter; struct gpio_desc *gpio; gpio = devm_gpiod_get_optional(dev->dev, "scl", GPIOD_OUT_HIGH); @@ -831,13 +847,34 @@ static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev) rinfo->sda_gpiod = gpio; rinfo->recover_bus = i2c_generic_scl_recovery; - rinfo->prepare_recovery = i2c_dw_prepare_recovery; - rinfo->unprepare_recovery = i2c_dw_unprepare_recovery; - adap->bus_recovery_info = rinfo; dev_info(dev->dev, "running with gpio recovery mode! scl%s", rinfo->sda_gpiod ? ",sda" : ""); + return 1; +} + +static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev) +{ + struct i2c_bus_recovery_info *rinfo = &dev->rinfo; + struct i2c_adapter *adap = &dev->adapter; + int ret; + + switch (dev->flags & MODEL_MASK) { + case MODEL_SOCFPGA: + ret = i2c_dw_init_socfpga_recovery_info(dev, rinfo); + break; + default: + ret = i2c_dw_init_generic_recovery_info(dev, rinfo); + break; + } + if (ret <= 0) + return ret; + + rinfo->prepare_recovery = i2c_dw_prepare_recovery; + rinfo->unprepare_recovery = i2c_dw_unprepare_recovery; + adap->bus_recovery_info = rinfo; + return 0; } diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c index 70ade5306e45..b33e015e6732 100644 --- a/drivers/i2c/busses/i2c-designware-platdrv.c +++ b/drivers/i2c/busses/i2c-designware-platdrv.c @@ -153,6 +153,7 @@ static const struct of_device_id dw_i2c_of_match[] = { { .compatible = "snps,designware-i2c", }, { .compatible = "mscc,ocelot-i2c", .data = (void *)MODEL_MSCC_OCELOT }, { .compatible = "baikal,bt1-sys-i2c", .data = (void *)MODEL_BAIKAL_BT1 }, + { .compatible = "intel,socfpga-i2c", .data = (void *)MODEL_SOCFPGA }, {}, }; MODULE_DEVICE_TABLE(of, dw_i2c_of_match);