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authorGao Pan <b54642@freescale.com>2015-10-23 20:28:54 +0800
committerWolfram Sang <wsa@the-dreams.de>2015-10-23 21:55:50 +0200
commit1c4b6c3bcf30d0804db0d0647d8ebeb862c6f7e5 (patch)
treea8773ecfa4e4f91be9bb41335d8326f78390fedb /Documentation/devicetree/bindings/i2c
parent3861841d2205714bfabaee4efcbb5e4202884852 (diff)
i2c: imx: implement bus recovery
Implement bus recovery methods for i2c-imx so we can recover from situations where SCL/SDA are stuck low. Once i2c bus SCL/SDA are stuck low during transfer, 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: Fugang Duan <B38611@freescale.com> Signed-off-by: Gao Pan <b54642@freescale.com> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'Documentation/devicetree/bindings/i2c')
-rw-r--r--Documentation/devicetree/bindings/i2c/i2c-imx.txt9
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-imx.txt b/Documentation/devicetree/bindings/i2c/i2c-imx.txt
index ce4311d726ae..eab5836ba7f9 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-imx.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-imx.txt
@@ -14,6 +14,10 @@ Optional properties:
The absence of the propoerty indicates the default frequency 100 kHz.
- dmas: A list of two dma specifiers, one for each entry in dma-names.
- dma-names: should contain "tx" and "rx".
+- 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
Examples:
@@ -37,4 +41,9 @@ i2c0: i2c@40066000 { /* i2c0 on vf610 */
dmas = <&edma0 0 50>,
<&edma0 0 51>;
dma-names = "rx","tx";
+ pinctrl-names = "default", "gpio";
+ pinctrl-0 = <&pinctrl_i2c1>;
+ pinctrl-1 = <&pinctrl_i2c1_gpio>;
+ scl-gpios = <&gpio5 26 GPIO_ACTIVE_HIGH>;
+ sda-gpios = <&gpio5 27 GPIO_ACTIVE_HIGH>;
};