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i2c: imx: implement bus recovery

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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>
This commit is contained in:
Gao Pan
2015-10-23 20:28:54 +08:00
committed by Wolfram Sang
parent 3861841d22
commit 1c4b6c3bcf
2 changed files with 80 additions and 0 deletions
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9
Documentation/devicetree/bindings/i2c/i2c-imx.txt
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@@ -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>;
};