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https://github.com/brain-hackers/u-boot-brain
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c54473cb25
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 <p.marczak@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Added braces in i2c_gpio_xfer() to fix style nit:
Signed-off-by: Simon Glass <sjg@chromium.org>
38 lines
757 B
Plaintext
38 lines
757 B
Plaintext
I2C gpio device binding
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=======================
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Driver:
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- drivers/i2c/i2c-gpio.c
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Software i2c device-tree node properties:
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Required:
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* #address-cells = <1>;
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* #size-cells = <0>;
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* compatible = "i2c-gpio";
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* gpios = <sda ...>, <scl ...>;
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Optional:
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* i2c-gpio,delay-us = <5>;
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The resulting transfer speed can be adjusted by setting the delay[us]
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between gpio-toggle operations. Speed [Hz] = 1000000 / 4 * udelay[us],
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It not defined, then default is 5us (~50KHz).
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Example:
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i2c-gpio@1 {
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#address-cells = <1>;
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#size-cells = <0>;
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compatible = "i2c-gpio";
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gpios = <&gpd1 0 GPIO_ACTIVE_HIGH>, /* SDA */
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<&gpd1 1 GPIO_ACTIVE_HIGH>; /* CLK */
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i2c-gpio,delay-us = <5>;
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some_device@5 {
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compatible = "some_device";
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reg = <0x5>;
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...
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};
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};
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