Messages in this thread | | | Date | Mon, 25 May 2020 12:20:25 +0200 | From | Michael Walle <> | Subject | Re: [PATCH v3 10/16] gpio: add a reusable generic gpio_chip using regmap |
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Am 2020-05-25 11:05, schrieb Bartosz Golaszewski: > wt., 12 maj 2020 o 16:41 Michael Walle <michael@walle.cc> napisał(a): >> >> >> + >> >> +MODULE_AUTHOR("Michael Walle <michael@walle.cc>"); >> >> +MODULE_DESCRIPTION("GPIO generic regmap driver core"); >> >> +MODULE_LICENSE("GPL"); >> >> diff --git a/include/linux/gpio-regmap.h b/include/linux/gpio-regmap.h >> >> new file mode 100644 >> >> index 000000000000..a868cbcde6e9 >> >> --- /dev/null >> >> +++ b/include/linux/gpio-regmap.h >> >> @@ -0,0 +1,69 @@ >> >> +/* SPDX-License-Identifier: GPL-2.0-only */ >> >> + >> >> +#ifndef _LINUX_GPIO_REGMAP_H >> >> +#define _LINUX_GPIO_REGMAP_H >> >> + >> >> +struct gpio_regmap; >> >> + >> >> +#define GPIO_REGMAP_ADDR_ZERO ((unsigned long)(-1)) >> >> +#define GPIO_REGMAP_ADDR(addr) ((addr) ? : GPIO_REGMAP_ADDR_ZERO) >> >> + >> > >> > What if the addr is actually 0? >> >> Then the driver has to set GPIO_REGMAP_ADDR_ZERO or use the >> convenience >> macro GPIO_REGMAP_ADDR. >> >> So you can have >> >> struct gpio_regmap_config config = { 0 }; >> config.reg_dat_base = 0x10; >> config.reg_dir_out_base = 0x20; >> >> or >> >> config.reg_dat_base = GPIO_REGMAP_ADDR_ZERO; >> >> or if you can't be sure if the RHS value might be zero: >> >> config.reg_dat_base = GPIO_REGMAP_ADDR(reg); >> >> >> > Maybe drop GPIO_REGMAP_ADDR and require users to set unused registers >> > to GPIO_REGMAP_ADDR_ZERO? >> >> Thats bad because: >> * you'd have to set plenty of unused base registers for a simple >> driver >> * if there will be additional properties in the future, you have to >> touch >> all other drivers, because they are initialized as 0 (ie. valid >> reg >> 0). >> >> >> +/** >> >> + * struct gpio_regmap_config - Description of a generic regmap >> >> gpio_chip. >> >> + * >> >> + * @parent: The parent device >> >> + * @regmap: The regmap used to access the registers >> >> + * given, the name of the device is used >> >> + * @label: (Optional) Descriptive name for GPIO >> >> controller. >> >> + * If not given, the name of the device is used. >> >> + * @ngpio: Number of GPIOs >> >> + * @reg_dat_base: (Optional) (in) register base address >> >> + * @reg_set_base: (Optional) set register base address >> >> + * @reg_clr_base: (Optional) clear register base address >> >> + * @reg_dir_in_base: (Optional) out setting register base address >> >> + * @reg_dir_out_base: (Optional) in setting register base address >> > >> > The two above are inverted I think? >> good catch. >> >> > Also: why the limitation of only supporting one at a time? >> >> they should be exclusive, either you have a register where you set the >> output bits to one, or the input bits. Maybe this need a bit more >> context >> above. in gpio-mmio.c you can set both and both are used in >> set_direction(), but only one is read in get_direction(). >> >> That being said, I have no strong opinion wether they should be >> exclusive >> or not, besides the symmetry of set_/get_direction(). >> >> -michael >> > > Sorry for the late response, your comments make sense to me. Are you > going to submit a v4 before the v5.8 merge window?
I'm currently stuck with how to handle the MFD part. Ie. Rob doesn't seem to like the logicial device numbering - or at least there wasn't an answer to that one anymore, see patch 5/16.
If you like I could submit this patch on its own. But then there wouldn't be a user for it.
-michael
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