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 > + Make these common properties in i2c.txt (and a separate patch). > 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>; > }; -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
