On Thu, Apr 14, 2016 at 10:04:56PM +0800, Jisheng Zhang wrote: > Implement bus recovery methods for i2c designware so we can recover > from situations where SCL/SDA are stuck low. > > The recovery method is similar as i2c-imx: "config the i2c pinctrl to > gpio mode by calling pinctrl sleep set function, and then use GPIO to > emulate the i2c protocol to send nine dummy clock to recover i2c > device. After recovery, set i2c pinctrl to default group setting. > > Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx> > --- > depends on runtime pm patches > http://lists.infradead.org/pipermail/linux-arm-kernel/2016-April/422202.html > .../devicetree/bindings/i2c/i2c-designware.txt | 12 ++++++ > drivers/i2c/busses/i2c-designware-core.c | 6 ++- > drivers/i2c/busses/i2c-designware-core.h | 4 ++ > drivers/i2c/busses/i2c-designware-platdrv.c | 50 ++++++++++++++++++++++ > 4 files changed, 71 insertions(+), 1 deletion(-) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt > index fee26dc..51a55c6 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt > @@ -20,6 +20,13 @@ Optional properties : > - i2c-sda-falling-time-ns : should contain the SDA falling time in nanoseconds. > This value which is by default 300ns is used to compute the tHIGH period. > > + - scl-gpios: specify the gpio related to SCL pin > + > + - sda-gpios: specify the gpio related to SDA pin > + > + - pinctrl: add extra pinctrl to configure i2c pins to gpio function for i2c > + bus recovery, call it "gpio" state > + > Example : > > i2c@f0000 { > @@ -42,4 +49,9 @@ Example : > i2c-sda-hold-time-ns = <300>; > i2c-sda-falling-time-ns = <300>; > i2c-scl-falling-time-ns = <300>; > + pinctrl-names = "default", "gpio"; > + pinctrl-0 = <&pinctrl_i2c1_default>; > + pinctrl-1 = <&pinctrl_i2c1_gpio>; > + scl-gpios = <&porta 26 GPIO_ACTIVE_HIGH>; > + sda-gpios = <&porta 27 GPIO_ACTIVE_HIGH>; > }; > diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c > index 4255eaa..be40de1 100644 > --- a/drivers/i2c/busses/i2c-designware-core.c > +++ b/drivers/i2c/busses/i2c-designware-core.c > @@ -399,7 +399,10 @@ static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev) > while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) { > if (timeout <= 0) { > dev_warn(dev->dev, "timeout waiting for bus ready\n"); > - return -ETIMEDOUT; > + i2c_recover_bus(&dev->adapter); > + if (dw_readl(dev, DW_IC_STATUS) > + & DW_IC_STATUS_ACTIVITY) > + return -ETIMEDOUT; > } > timeout--; > usleep_range(1000, 1100); > @@ -665,6 +668,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) > /* wait for tx to complete */ > if (!wait_for_completion_timeout(&dev->cmd_complete, HZ)) { > dev_err(dev->dev, "controller timed out\n"); > + i2c_recover_bus(&dev->adapter); > /* i2c_dw_init implicitly disables the adapter */ > i2c_dw_init(dev); > ret = -ETIMEDOUT; > diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h > index cd409e7..26c84ee 100644 > --- a/drivers/i2c/busses/i2c-designware-core.h > +++ b/drivers/i2c/busses/i2c-designware-core.h > @@ -104,6 +104,10 @@ struct dw_i2c_dev { > u16 fs_lcnt; > int (*acquire_lock)(struct dw_i2c_dev *dev); > void (*release_lock)(struct dw_i2c_dev *dev); > + struct i2c_bus_recovery_info rinfo; > + struct pinctrl *pinctrl; > + struct pinctrl_state *pinctrl_pins_default; > + struct pinctrl_state *pinctrl_pins_gpio; > bool pm_runtime_disabled; > }; > > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c > index 1488cea..62bded9 100644 > --- a/drivers/i2c/busses/i2c-designware-platdrv.c > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c > @@ -33,6 +33,7 @@ > #include <linux/err.h> > #include <linux/interrupt.h> > #include <linux/of.h> > +#include <linux/of_gpio.h> > #include <linux/platform_device.h> > #include <linux/pm.h> > #include <linux/pm_runtime.h> > @@ -148,6 +149,49 @@ static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare) > return 0; > } > > +static void i2c_dw_plat_prepare_recovery(struct i2c_adapter *adap) > +{ > + struct dw_i2c_dev *dev = i2c_get_adapdata(adap); > + > + pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_gpio); > +} > + > +static void i2c_dw_plat_unprepare_recovery(struct i2c_adapter *adap) > +{ > + struct dw_i2c_dev *dev = i2c_get_adapdata(adap); > + > + pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default); > +} > + > +static void i2c_dw_plat_init_recovery_info(struct dw_i2c_dev *dev, > + struct platform_device *pdev) > +{ > + struct i2c_bus_recovery_info *rinfo = &dev->rinfo; > + > + dev->pinctrl_pins_default = pinctrl_lookup_state(dev->pinctrl, > + PINCTRL_STATE_DEFAULT); > + dev->pinctrl_pins_gpio = pinctrl_lookup_state(dev->pinctrl, > + "gpio"); > + rinfo->sda_gpio = of_get_named_gpio(pdev->dev.of_node, "sda-gpios", 0); > + rinfo->scl_gpio = of_get_named_gpio(pdev->dev.of_node, "scl-gpios", 0); > + > + if (!gpio_is_valid(rinfo->sda_gpio) || > + !gpio_is_valid(rinfo->scl_gpio) || > + IS_ERR(dev->pinctrl_pins_default) || > + IS_ERR(dev->pinctrl_pins_gpio)) { > + dev_dbg(&pdev->dev, "recovery information incomplete\n"); > + return; > + } > + > + dev_dbg(&pdev->dev, "using scl-gpio %d and sda-gpio %d for recovery\n", > + rinfo->sda_gpio, rinfo->scl_gpio); > + > + rinfo->prepare_recovery = i2c_dw_plat_prepare_recovery; > + rinfo->unprepare_recovery = i2c_dw_plat_unprepare_recovery; > + rinfo->recover_bus = i2c_generic_gpio_recovery; This whole thing is DT specific and I don't see how we can do the same for ACPI. Should it be enabled only when the controller was enumerated from DT? > + dev->adapter.bus_recovery_info = rinfo; > +} > + > static int dw_i2c_plat_probe(struct platform_device *pdev) > { > struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev); > @@ -165,6 +209,12 @@ static int dw_i2c_plat_probe(struct platform_device *pdev) > if (!dev) > return -ENOMEM; > > + dev->pinctrl = devm_pinctrl_get(&pdev->dev); > + if (IS_ERR(dev->pinctrl)) > + return PTR_ERR(dev->pinctrl); > + > + i2c_dw_plat_init_recovery_info(dev, pdev); > + > mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); > dev->base = devm_ioremap_resource(&pdev->dev, mem); > if (IS_ERR(dev->base)) > -- > 2.8.0.rc3 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
