>>>>> "Jean" == Jean Delvare <khali@xxxxxxxxxxxx> writes:
Jean> Hi Peter,
Jean> Thanks for the updated patch.
You're welcome. Thanks for the feedback.
>> SCL/SDA of the master I2C bus is multiplexed to virtual bus 1..M
>> according to the settings of the GPIO pins 1..N.
Jean> Again: these are not virtual buses. These are bus segments behind a
Jean> mux, and they are as real as the trunk segment in front of the mux.
Ok, I renamed every instance of 'virtual bus' with 'bus segment'.
Jean> I'm eager to give it a try on my own PC system, where the SMBus
Jean> is multiplexed using ICH10 GPIO pins. Unfortunately I don't think
Jean> there is a driver for the Intel ICH GPIO pins, so I'll have to
Jean> write one. And then I'll have to write some glue code to
Jean> instantiate the relevant platform device on my system. I'll let
Jean> you know when I get there.
Nice!
>> +static struct gpio_i2cmux_platform_data myboard_i2cmux_data = {
>> + .parent = 1,
>> + .base_nr = 2, /* optional */
>> + .values = myboard_gpiomux_values,
>> + .n_values = ARRAY_SIZE(myboard_gpiomux_values),
>> + .gpio = myboard_gpiomux_gpios,
Jean> .gpios
>> + .gpios = ARRAY_SIZE(myboard_gpiomux_gpios),
Jean> .n_gpios
Ups, fixed.
>> +GENERIC GPIO I2C MULTIPLEXER DRIVER
>> +M: Peter Korsgaard <peter.korsgaard@xxxxxxxxx>
>> +L: linux-i2c@xxxxxxxxxxxxxxx
>> +S: Supported
>> +F: drivers/i2c/muxes/gpio-i2cmux.c
>> +F: include/linux/gpio-i2mux.h
Jean> Typo: gpio-i2cmux.h. And you're missing:
Jean> F: Documentation/i2c/muxes/gpio-i2cmux
Fixed.
>> + config I2C_MUX_GPIO
>> + tristate "GPIO-based I2C multiplexer"
>> + depends on GENERIC_GPIO
>> + help
>> + If you say yes to this option, support will be included for a
>> + GPIO based I2C multiplexer. This driver provides access to
>> + I2C busses connected through a MUX, which is controlled
>> + through GPIO pins.
>> +
>> + This driver can also be built as a module. If so, the module
>> + will be called gpio-i2cmux.
>> +
Jean> Alphabetic order -> goes at the beginning of the list.
>> +obj-$(CONFIG_I2C_MUX_GPIO) += gpio-i2cmux.o
Jean> Alphabetic order -> goes at the beginning of the list.
Fixed.
>> + for (i = 0; i < pdata->n_values; i++) {
>> + u32 nr = pdata->base_nr ? (pdata->base_nr + i) : 0;
>> + bool has_idle = (pdata->idle != (unsigned)-1);
Jean> has_idle doesn't depend on i, so it would be more efficiently set
Jean> outside the loop. You could even store a function pointer instead of a
Jean> boolean value, to be even more efficient.
Jean> BTW, would it make sense to
Jean> #define GPIO_I2CMUX_NO_IDLE ((unsigned)-1)
Jean> to avoid arbitrary cast and constant in the code?
Ok, added define to platform header, and changed the probe code to use
a function pointer instead.
Will send v4 shortly - Thanks for the review.
--
Bye, Peter Korsgaard
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