| Message ID | 20200115115422.17097-3-codrin.ciubotariu@microchip.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | i2c bus recovery for Microchip SoCs | expand |
On Wed, Jan 15, 2020 at 01:54:18PM +0200, Codrin Ciubotariu wrote: > From: Kamel Bouhara <kamel.bouhara@bootlin.com> > > Implement i2c bus recovery when slaves devices might hold SDA low. > In this case re-assign SCL/SDA to gpios and issue 9 dummy clock pulses > until the slave release SDA. > > Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com> > Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com> Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com> > --- > > Changes in v3: > - removed unnecessary condition from info print; > - removed unneded declarations; > > Changes in v2: > - called i2c_recover_bus() after an error occurs, if SDA is down; > - release gpios if recovery information is incomplete; > > drivers/i2c/busses/i2c-at91-master.c | 78 ++++++++++++++++++++++++++++ > drivers/i2c/busses/i2c-at91.h | 4 ++ > 2 files changed, 82 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c > index 7a862e00b475..0aba51a7df32 100644 > --- a/drivers/i2c/busses/i2c-at91-master.c > +++ b/drivers/i2c/busses/i2c-at91-master.c > @@ -18,11 +18,13 @@ > #include <linux/dma-mapping.h> > #include <linux/dmaengine.h> > #include <linux/err.h> > +#include <linux/gpio/consumer.h> > #include <linux/i2c.h> > #include <linux/interrupt.h> > #include <linux/io.h> > #include <linux/of.h> > #include <linux/of_device.h> > +#include <linux/pinctrl/consumer.h> > #include <linux/platform_device.h> > #include <linux/platform_data/dma-atmel.h> > #include <linux/pm_runtime.h> > @@ -478,6 +480,7 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) > unsigned long time_left; > bool has_unre_flag = dev->pdata->has_unre_flag; > bool has_alt_cmd = dev->pdata->has_alt_cmd; > + struct i2c_bus_recovery_info *rinfo = &dev->rinfo; > > /* > * WARNING: the TXCOMP bit in the Status Register is NOT a clear on > @@ -637,6 +640,13 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) > at91_twi_write(dev, AT91_TWI_CR, > AT91_TWI_THRCLR | AT91_TWI_LOCKCLR); > } > + > + if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) { > + dev_dbg(dev->dev, > + "SDA is down; clear bus using gpio\n"); > + i2c_recover_bus(&dev->adapter); > + } > + > return ret; > } > > @@ -806,6 +816,70 @@ static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr) > return ret; > } > > +static void at91_prepare_twi_recovery(struct i2c_adapter *adap) > +{ > + struct at91_twi_dev *dev = i2c_get_adapdata(adap); > + > + pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_gpio); > +} > + > +static void at91_unprepare_twi_recovery(struct i2c_adapter *adap) > +{ > + struct at91_twi_dev *dev = i2c_get_adapdata(adap); > + > + pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default); > +} > + > +static int at91_init_twi_recovery_info(struct platform_device *pdev, > + struct at91_twi_dev *dev) > +{ > + struct i2c_bus_recovery_info *rinfo = &dev->rinfo; > + > + dev->pinctrl = devm_pinctrl_get(&pdev->dev); > + if (!dev->pinctrl || IS_ERR(dev->pinctrl)) { > + dev_info(dev->dev, "can't get pinctrl, bus recovery not supported\n"); > + return PTR_ERR(dev->pinctrl); > + } > + > + dev->pinctrl_pins_default = pinctrl_lookup_state(dev->pinctrl, > + PINCTRL_STATE_DEFAULT); > + dev->pinctrl_pins_gpio = pinctrl_lookup_state(dev->pinctrl, > + "gpio"); > + rinfo->sda_gpiod = devm_gpiod_get(&pdev->dev, "sda", GPIOD_IN); > + if (PTR_ERR(rinfo->sda_gpiod) == -EPROBE_DEFER) > + return -EPROBE_DEFER; > + > + rinfo->scl_gpiod = devm_gpiod_get(&pdev->dev, "scl", > + GPIOD_OUT_HIGH_OPEN_DRAIN); > + if (PTR_ERR(rinfo->scl_gpiod) == -EPROBE_DEFER) > + return -EPROBE_DEFER; > + > + if (IS_ERR(rinfo->sda_gpiod) || > + IS_ERR(rinfo->scl_gpiod) || > + IS_ERR(dev->pinctrl_pins_default) || > + IS_ERR(dev->pinctrl_pins_gpio)) { > + dev_info(&pdev->dev, "recovery information incomplete\n"); > + if (!IS_ERR(rinfo->sda_gpiod)) { > + gpiod_put(rinfo->sda_gpiod); > + rinfo->sda_gpiod = NULL; > + } > + if (!IS_ERR(rinfo->scl_gpiod)) { > + gpiod_put(rinfo->scl_gpiod); > + rinfo->scl_gpiod = NULL; > + } > + return -EINVAL; > + } > + > + dev_info(&pdev->dev, "using scl, sda for recovery\n"); > + > + rinfo->prepare_recovery = at91_prepare_twi_recovery; > + rinfo->unprepare_recovery = at91_unprepare_twi_recovery; > + rinfo->recover_bus = i2c_generic_scl_recovery; > + dev->adapter.bus_recovery_info = rinfo; > + > + return 0; > +} > + > int at91_twi_probe_master(struct platform_device *pdev, > u32 phy_addr, struct at91_twi_dev *dev) > { > @@ -838,6 +912,10 @@ int at91_twi_probe_master(struct platform_device *pdev, > "i2c-analog-filter"); > at91_calc_twi_clock(dev); > > + rc = at91_init_twi_recovery_info(pdev, dev); > + if (rc == -EPROBE_DEFER) > + return rc; > + > dev->adapter.algo = &at91_twi_algorithm; > dev->adapter.quirks = &at91_twi_quirks; > > diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h > index 977a67bc0f88..f57a6cab96b4 100644 > --- a/drivers/i2c/busses/i2c-at91.h > +++ b/drivers/i2c/busses/i2c-at91.h > @@ -151,6 +151,10 @@ struct at91_twi_dev { > u32 fifo_size; > struct at91_twi_dma dma; > bool slave_detected; > + struct i2c_bus_recovery_info rinfo; > + struct pinctrl *pinctrl; > + struct pinctrl_state *pinctrl_pins_default; > + struct pinctrl_state *pinctrl_pins_gpio; > #ifdef CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL > unsigned smr; > struct i2c_client *slave; > -- > 2.20.1 >
On Wed, Jan 15, 2020 at 01:54:18PM +0200, Codrin Ciubotariu wrote: > From: Kamel Bouhara <kamel.bouhara@bootlin.com> > > Implement i2c bus recovery when slaves devices might hold SDA low. > In this case re-assign SCL/SDA to gpios and issue 9 dummy clock pulses > until the slave release SDA. > > Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com> > Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com> Applied to for-next, thanks! The implementation is very similar to i2c-imx. Maybe we should move this mechanism into the core somewhen...
diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c index 7a862e00b475..0aba51a7df32 100644 --- a/drivers/i2c/busses/i2c-at91-master.c +++ b/drivers/i2c/busses/i2c-at91-master.c @@ -18,11 +18,13 @@ #include <linux/dma-mapping.h> #include <linux/dmaengine.h> #include <linux/err.h> +#include <linux/gpio/consumer.h> #include <linux/i2c.h> #include <linux/interrupt.h> #include <linux/io.h> #include <linux/of.h> #include <linux/of_device.h> +#include <linux/pinctrl/consumer.h> #include <linux/platform_device.h> #include <linux/platform_data/dma-atmel.h> #include <linux/pm_runtime.h> @@ -478,6 +480,7 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) unsigned long time_left; bool has_unre_flag = dev->pdata->has_unre_flag; bool has_alt_cmd = dev->pdata->has_alt_cmd; + struct i2c_bus_recovery_info *rinfo = &dev->rinfo; /* * WARNING: the TXCOMP bit in the Status Register is NOT a clear on @@ -637,6 +640,13 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_THRCLR | AT91_TWI_LOCKCLR); } + + if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) { + dev_dbg(dev->dev, + "SDA is down; clear bus using gpio\n"); + i2c_recover_bus(&dev->adapter); + } + return ret; } @@ -806,6 +816,70 @@ static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr) return ret; } +static void at91_prepare_twi_recovery(struct i2c_adapter *adap) +{ + struct at91_twi_dev *dev = i2c_get_adapdata(adap); + + pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_gpio); +} + +static void at91_unprepare_twi_recovery(struct i2c_adapter *adap) +{ + struct at91_twi_dev *dev = i2c_get_adapdata(adap); + + pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default); +} + +static int at91_init_twi_recovery_info(struct platform_device *pdev, + struct at91_twi_dev *dev) +{ + struct i2c_bus_recovery_info *rinfo = &dev->rinfo; + + dev->pinctrl = devm_pinctrl_get(&pdev->dev); + if (!dev->pinctrl || IS_ERR(dev->pinctrl)) { + dev_info(dev->dev, "can't get pinctrl, bus recovery not supported\n"); + return PTR_ERR(dev->pinctrl); + } + + dev->pinctrl_pins_default = pinctrl_lookup_state(dev->pinctrl, + PINCTRL_STATE_DEFAULT); + dev->pinctrl_pins_gpio = pinctrl_lookup_state(dev->pinctrl, + "gpio"); + rinfo->sda_gpiod = devm_gpiod_get(&pdev->dev, "sda", GPIOD_IN); + if (PTR_ERR(rinfo->sda_gpiod) == -EPROBE_DEFER) + return -EPROBE_DEFER; + + rinfo->scl_gpiod = devm_gpiod_get(&pdev->dev, "scl", + GPIOD_OUT_HIGH_OPEN_DRAIN); + if (PTR_ERR(rinfo->scl_gpiod) == -EPROBE_DEFER) + return -EPROBE_DEFER; + + if (IS_ERR(rinfo->sda_gpiod) || + IS_ERR(rinfo->scl_gpiod) || + IS_ERR(dev->pinctrl_pins_default) || + IS_ERR(dev->pinctrl_pins_gpio)) { + dev_info(&pdev->dev, "recovery information incomplete\n"); + if (!IS_ERR(rinfo->sda_gpiod)) { + gpiod_put(rinfo->sda_gpiod); + rinfo->sda_gpiod = NULL; + } + if (!IS_ERR(rinfo->scl_gpiod)) { + gpiod_put(rinfo->scl_gpiod); + rinfo->scl_gpiod = NULL; + } + return -EINVAL; + } + + dev_info(&pdev->dev, "using scl, sda for recovery\n"); + + rinfo->prepare_recovery = at91_prepare_twi_recovery; + rinfo->unprepare_recovery = at91_unprepare_twi_recovery; + rinfo->recover_bus = i2c_generic_scl_recovery; + dev->adapter.bus_recovery_info = rinfo; + + return 0; +} + int at91_twi_probe_master(struct platform_device *pdev, u32 phy_addr, struct at91_twi_dev *dev) { @@ -838,6 +912,10 @@ int at91_twi_probe_master(struct platform_device *pdev, "i2c-analog-filter"); at91_calc_twi_clock(dev); + rc = at91_init_twi_recovery_info(pdev, dev); + if (rc == -EPROBE_DEFER) + return rc; + dev->adapter.algo = &at91_twi_algorithm; dev->adapter.quirks = &at91_twi_quirks; diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h index 977a67bc0f88..f57a6cab96b4 100644 --- a/drivers/i2c/busses/i2c-at91.h +++ b/drivers/i2c/busses/i2c-at91.h @@ -151,6 +151,10 @@ struct at91_twi_dev { u32 fifo_size; struct at91_twi_dma dma; bool slave_detected; + struct i2c_bus_recovery_info rinfo; + struct pinctrl *pinctrl; + struct pinctrl_state *pinctrl_pins_default; + struct pinctrl_state *pinctrl_pins_gpio; #ifdef CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL unsigned smr; struct i2c_client *slave;