Use of pinctrl-single for external device over I2C

[Vaibhav Hiremath]

Hi,

I am working on enabling support for PMIC 88PM860 device in the
mainline.

In 88PM860 (and family of devices) few pins are labelled as GPIO's, to
be precise, in 88PM860, we have 8 GPIO's (ana & dig).


I was looking at pinctrl-single driver, as it seems it can not handle
pinmux configuration of external device (in this case its over I2C), as
it uses raw read/write api's.

I see below lines in the driver,


/*
 * REVISIT: Reads and writes could eventually use regmap or something
 * generic. But at least on omaps, some mux registers are performance
 * critical as they may need to be remuxed every time before and after
 * idle. Adding tests for register access width for every read and
 * write like regmap is doing is not desired, and caching the registers
 * does not help in this case.
 */


Should be not have flag for this and use regmap_ variants? If we
implement flag based approach then same driver can be reused for pinmux
configuration of external device.


Just to give more clarity, Let me describe my use-case below,

The platform which I have is based on PXA1928 and 88PM860 chipsets,
where 88PM860.GPIO_0 is connected back to PXA1928.EXT_32K_IN.

GPIO_0 need to configured in mode '4'.

As per spec, 88PM860.GPIO_0 can be configured to

 000 = GPIO input mode
 001 = GPIO output mode
 010 = SLEEPOUTN mirror mode
 011 = Buck4 FPWM enable
 100 = 32 Khz output buffer mode
 101 = PMICINTN output mode
 110 = HW_RESET1 mode
 111 = HW_RESET2 mode


Please let me know if there is already an alternative for this, which I
missed.

Thanks,
Vaibhav



Thanks,
Vaibhav
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