From c54473cb25968be53e6b47527d5970b03a3cf41d Mon Sep 17 00:00:00 2001 From: Przemyslaw Marczak Date: Tue, 31 Mar 2015 18:57:18 +0200 Subject: dm: i2c: add i2c-gpio driver This commit adds driver model support to software emulated i2c bus driver. This driver supports kernel-style device tree bindings. Fdt properties in use: - compatible - "i2c-gpio" - gpios - data and clock GPIO pin phandles - delay-us - micro seconds delay between GPIOs toggle operations, which is 1/4 of I2C speed clock period. Added: - Config: CONFIG_DM_I2C_GPIO - File: drivers/i2c/i2c-gpio.c - File: doc/device-tree-bindings/i2c/i2c-gpio.txt Driver base code is taken from: drivers/i2c/soft-i2c.c, changes: - use "i2c-gpio" naming - update comments style - move preprocesor macros into functions - add device tree support - add driver model i2c support - code cleanup, - add Kconfig entry Signed-off-by: Przemyslaw Marczak Acked-by: Simon Glass Added braces in i2c_gpio_xfer() to fix style nit: Signed-off-by: Simon Glass --- doc/device-tree-bindings/i2c/i2c-gpio.txt | 37 +++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 doc/device-tree-bindings/i2c/i2c-gpio.txt (limited to 'doc') diff --git a/doc/device-tree-bindings/i2c/i2c-gpio.txt b/doc/device-tree-bindings/i2c/i2c-gpio.txt new file mode 100644 index 0000000000..ba56ed5dea --- /dev/null +++ b/doc/device-tree-bindings/i2c/i2c-gpio.txt @@ -0,0 +1,37 @@ +I2C gpio device binding +======================= + +Driver: +- drivers/i2c/i2c-gpio.c + +Software i2c device-tree node properties: +Required: +* #address-cells = <1>; +* #size-cells = <0>; +* compatible = "i2c-gpio"; +* gpios = , ; + +Optional: +* i2c-gpio,delay-us = <5>; + The resulting transfer speed can be adjusted by setting the delay[us] + between gpio-toggle operations. Speed [Hz] = 1000000 / 4 * udelay[us], + It not defined, then default is 5us (~50KHz). + +Example: + +i2c-gpio@1 { + #address-cells = <1>; + #size-cells = <0>; + + compatible = "i2c-gpio"; + gpios = <&gpd1 0 GPIO_ACTIVE_HIGH>, /* SDA */ + <&gpd1 1 GPIO_ACTIVE_HIGH>; /* CLK */ + + i2c-gpio,delay-us = <5>; + + some_device@5 { + compatible = "some_device"; + reg = <0x5>; + ... + }; +}; -- cgit v1.2.1