On Tue, Apr 23, 2024 at 02:12:33PM +0200, Linus Walleij wrote:
> The ath9k has an odd use of system-wide GPIOs: if the chip
> does not have internal GPIO capability, it will try to obtain a
> GPIO line from the system GPIO controller:
>
> if (BIT(gpio) & ah->caps.gpio_mask)
> ath9k_hw_gpio_cfg_wmac(...);
> else if (AR_SREV_SOC(ah))
> ath9k_hw_gpio_cfg_soc(ah, gpio, out, label);
>
> Where ath9k_hw_gpio_cfg_soc() will attempt to issue
> gpio_request_one() passing the local GPIO number of the controller
> (0..31) to gpio_request_one().
>
> This is somewhat peculiar and possibly even dangerous: there is
> nowadays no guarantee of the numbering of these system-wide
> GPIOs, and assuming that GPIO 0..31 as used by ath9k would
> correspond to GPIOs 0..31 on the system as a whole seems a bit
> wild.
>
> Register all 32 GPIOs at index 0..31 directly in the ATH79K
> GPIO driver and associate with WIFI if and only if we are probing
> ATH79K wifi from the AHB bus (used for SoCs).
...
> +/*
> + * This registers all of the ath79k GPIOs as descriptors to be picked
> + * directly from the ATH79K wifi driver if the two are jitted together
> + * in the same SoC.
> + */
> +#define ATH79K_WIFI_DESCS 32
> +static int ath79_gpio_register_wifi_descriptors(struct device *dev,
> + const char *label)
> +{
> + struct gpiod_lookup_table *lookup;
> + int i;
unsigned ?
> + /* Create a gpiod lookup using gpiochip-local offsets + 1 for NULL */
> + lookup = devm_kzalloc(dev,
> + struct_size(lookup, table, ATH79K_WIFI_DESCS + 1),
> + GFP_KERNEL);
> +
Besides unneeded blank line the above has a broken indentation.
> + if (!lookup)
> + return -ENOMEM;
> +
> + lookup->dev_id = "ath9k";
> +
> + for (i = 0; i < ATH79K_WIFI_DESCS; i++) {
> + lookup->table[i] = (struct gpiod_lookup)
This is not needed as GPIO_LOOKUP_IDX() is a compound literal.
> + GPIO_LOOKUP_IDX(label, 0, NULL, i,
> + GPIO_ACTIVE_HIGH);
Hence:
lookup->table[i] =
GPIO_LOOKUP_IDX(label, 0, NULL, i, GPIO_ACTIVE_HIGH);
> + }
> +
> + gpiod_add_lookup_table(lookup);
> +
> + return 0;
> +}
...
> + /* Obtains a system specific GPIO descriptor from another GPIO controller */
> + gpiod = devm_gpiod_get_index(ah->dev, NULL, gpio, flags);
> +
Unneeded blank line.
> + if (IS_ERR(gpiod)) {
> + err = PTR_ERR(gpiod);
> ath_err(ath9k_hw_common(ah), "request GPIO%d failed:%d\n",
> gpio, err);
> return;
> }
--
With Best Regards,
Andy Shevchenko
