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SubjectRe: [PATCH v3 1/4] gpio: idio-16: Migrate to the regmap API
On Fri, Mar 24, 2023 at 05:45:41PM -0400, William Breathitt Gray wrote:
> The regmap API supports IO port accessors so we can take advantage of
> regmap abstractions rather than handling access to the device registers
> directly in the driver.
>
> By leveraging the regmap API, the idio-16 library is reduced to simply a
> devm_idio_16_regmap_register() function and a configuration structure
> struct idio_16_regmap_config.
>
> Legacy functions and code will be removed once all consumers have
> migrated to the new idio-16 library interface.
>
> For IDIO-16 devices we have the following IRQ registers:
>
> Base Address +1 (Write): Clear Interrupt
> Base Address +2 (Read): Enable Interrupt
> Base Address +2 (Write): Disable Interrupt
>
> An interrupt is asserted whenever a change-of-state is detected on any
> of the inputs. Any write to 0x2 will disable interrupts, while any read
> will enable interrupts. Interrupts are cleared by a write to 0x1.
>
> For 104-IDIO-16 devices, there is no IRQ status register, so software
> has to assume that if an interrupt is raised then it was for the
> 104-IDIO-16 device.
>
> For PCI-IDIO-16 devices, there is an additional IRQ register:
>
> Base Address +6 (Read): Interrupt Status
>
> Interrupt status can be read from 0x6 where bit 2 set indicates that an
> IRQ has been generated.

...

> +static int idio_16_reg_mask_xlate(struct gpio_regmap *const gpio, const unsigned int base,
> + const unsigned int offset, unsigned int *const reg,
> + unsigned int *const mask)
> +{
> + unsigned int stride;

> + if (base != IDIO_16_DAT_BASE)
> + /* Should never reach this path */
> + return -EINVAL;

Then why do we have this test at all?

> + /* Input lines start at GPIO 16 */
> + if (offset < 16) {
> + stride = offset / IDIO_16_NGPIO_PER_REG;
> + *reg = IDIO_16_OUT_BASE + stride * IDIO_16_REG_STRIDE;
> + } else {
> + stride = (offset - 16) / IDIO_16_NGPIO_PER_REG;
> + *reg = IDIO_16_IN_BASE + stride * IDIO_16_REG_STRIDE;
> + }
> +
> + *mask = BIT(offset % IDIO_16_NGPIO_PER_REG);
> +
> + return 0;
> +}

...

> +static const char *idio_16_names[IDIO_16_NGPIO] = {
> + "OUT0", "OUT1", "OUT2", "OUT3", "OUT4", "OUT5", "OUT6", "OUT7", "OUT8", "OUT9", "OUT10",
> + "OUT11", "OUT12", "OUT13", "OUT14", "OUT15", "IIN0", "IIN1", "IIN2", "IIN3", "IIN4", "IIN5",
> + "IIN6", "IIN7", "IIN8", "IIN9", "IIN10", "IIN11", "IIN12", "IIN13", "IIN14", "IIN15",

I believe this would look much better if formatted on the 8 basis per line.

> +};

...

> +int devm_idio_16_regmap_register(struct device *const dev,
> + const struct idio_16_regmap_config *const config)
> +{
> + struct gpio_regmap_config gpio_config = {};
> + int err;
> + struct idio_16_data *data;
> + struct regmap_irq_chip *chip;
> + struct regmap_irq_chip_data *chip_data;
> +
> + if (!config->parent)
> + return -EINVAL;
> +
> + if (!config->map)
> + return -EINVAL;
> +
> + if (!config->regmap_irqs)
> + return -EINVAL;
> +
> + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> + data->map = config->map;
> +
> + chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
> + if (!chip)
> + return -ENOMEM;
> +
> + chip->name = dev_name(dev);
> + chip->status_base = IDIO_16_INTERRUPT_STATUS;
> + chip->mask_base = IDIO_16_ENABLE_IRQ;
> + chip->ack_base = IDIO_16_CLEAR_INTERRUPT;
> + chip->no_status = config->no_status;
> + chip->num_regs = 1;
> + chip->irqs = config->regmap_irqs;
> + chip->num_irqs = config->num_regmap_irqs;
> + chip->handle_mask_sync = idio_16_handle_mask_sync;
> + chip->irq_drv_data = data;
> +
> + /* Disable IRQ to prevent spurious interrupts before we're ready */
> + err = regmap_write(data->map, IDIO_16_DISABLE_IRQ, 0x00);
> + if (err)
> + return err;
> +
> + err = devm_regmap_add_irq_chip(dev, data->map, config->irq, 0, 0, chip, &chip_data);
> + if (err) {

> + dev_err(dev, "IRQ registration failed (%d)\n", err);
> + return err;

return dev_err_probe(...);

devm_*() can't be called otherwise. If it's not the case the caller abuses
devm_*() to begin with. So, it's the _part_ of the ->probe() sequence.

> + }
> +
> + if (config->filters) {
> + /* Deactivate input filters */
> + err = regmap_write(data->map, IDIO_16_DEACTIVATE_INPUT_FILTERS, 0x00);
> + if (err)
> + return err;
> + }
> +
> + gpio_config.parent = config->parent;
> + gpio_config.regmap = data->map;
> + gpio_config.ngpio = IDIO_16_NGPIO;
> + gpio_config.names = idio_16_names;
> + gpio_config.reg_dat_base = GPIO_REGMAP_ADDR(IDIO_16_DAT_BASE);
> + gpio_config.reg_set_base = GPIO_REGMAP_ADDR(IDIO_16_DAT_BASE);
> + gpio_config.ngpio_per_reg = IDIO_16_NGPIO_PER_REG;
> + gpio_config.reg_stride = IDIO_16_REG_STRIDE;
> + gpio_config.irq_domain = regmap_irq_get_domain(chip_data);
> + gpio_config.reg_mask_xlate = idio_16_reg_mask_xlate;
> +
> + return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &gpio_config));
> +}

--
With Best Regards,
Andy Shevchenko


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