On Fri, 15 Apr 2016 10:07:46 +0300 Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > On Fri, Apr 15, 2016 at 02:08:43PM +0800, Jisheng Zhang wrote: > > Dear Mika, > > > > On Thu, 14 Apr 2016 17:39:16 +0300 Mika Westerberg 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; > > > > For ACPI, we should return here, right? > > I hope so. And I do not want to see any useless messages about > incomplete recovery information on my PC. Got your points. > > > > > + } > > > > + > > > > + 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? > > > > Per my understanding, for ACPI, the pinctrl_pins_default, pinctrl_pins_gpio, > > sda_gpio and scl_gpio will be invalid or err, so we won't setup rinfo > > at all. However, I have no acpi platform which have i2c designware to double > > confirm. > > What happens to those of_get_ functions when you pass NULL of_node? If > they do not crash then I suppose it is fine. I just checked the code, If CONFIG_OF isn't enabled, of_get_* will return error. If CONFIG_OF is enabled, but NULL of_node is passed, of_get_* will also return error, so it's fine ;) > > Anyhow it might be good idea to do something like > > if (!pdev->dev.of_node) > return; > > in the beginning of that function. Sounds a good idea, will do in next version. Thanks for your review, Jisheng -- 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
