Re: [PATCH v2 4/4] gpio: i8255: Migrate to regmap API

From: Michael Walle
Date: Thu Nov 17 2022 - 11:19:19 EST


Hi,

Am 2022-11-11 02:55, schrieb William Breathitt Gray:

+ config.map = devm_regmap_init_mmio(dev, regs, &gpiomm_regmap_config);
+ if (IS_ERR(config.map))
+ return PTR_ERR(config.map);

I've just skimmed over your patch and noticed you're using an mmio
regmap. Please note that for now, gpio-regmap unconditionally sets
.can_sleep to true in the gpiochip [1]. So the users would need to
use the _cansleep() variants. See a proposal below.

+int devm_i8255_regmap_register(struct device *const dev,
+ const struct i8255_regmap_config *const config)
+{
+ struct gpio_regmap_config gpio_config = {0};
+ unsigned long i;
+ int err;
+
+ if (!config->parent)
+ return -EINVAL;
+
+ if (!config->map)
+ return -EINVAL;
+
+ if (!config->num_ppi)
+ return -EINVAL;
+
+ for (i = 0; i < config->num_ppi; i++) {
+ err = i8255_ppi_init(config->map, i * 4);
+ if (err)
+ return err;
+ }
+
+ gpio_config.parent = config->parent;
+ gpio_config.regmap = config->map;

I'd propose to add a new config flag to indicate that accesses to
the device will be fast:

gpio_config.regmap_has_fast_io = true;

which will then set gpio->can_sleep = false.

-michael

+ gpio_config.ngpio = I8255_NGPIO * config->num_ppi;
+ gpio_config.names = config->names;
+ gpio_config.reg_dat_base = GPIO_REGMAP_ADDR(I8255_REG_DAT_BASE);
+ gpio_config.reg_set_base = GPIO_REGMAP_ADDR(I8255_REG_DAT_BASE);
+ gpio_config.reg_dir_in_base = GPIO_REGMAP_ADDR(I8255_REG_DIR_IN_BASE);
+ gpio_config.ngpio_per_reg = I8255_NGPIO_PER_REG;
+ gpio_config.irq_domain = config->domain;
+ gpio_config.reg_mask_xlate = i8255_reg_mask_xlate;
+
+ return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &gpio_config));
+}
+EXPORT_SYMBOL_NS_GPL(devm_i8255_regmap_register, I8255);

[1] https://elixir.bootlin.com/linux/v6.1-rc5/source/drivers/gpio/gpio-regmap.c#L260