On Thu, Apr 14, 2016 at 10:39 PM, Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > 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? > For ACPI, probably result in the panic-alike function calling chain at i2c_dw_init --> dev->get_clk_rate_khz(dev). Mika, I think you need to take ACPI into account while not focus on DT only KM >> + 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 > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- 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
