Re: [PATCH v3 5/9] gpio: 104-idi-48: Migrate to gpio-regmap API

From: Andy Shevchenko
Date: Wed Nov 23 2022 - 12:31:28 EST


On Tue, Nov 22, 2022 at 02:11:02AM -0500, 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. Despite the underlying interface being based on
> i8255, it is simpler to use the gpio-regmap API directly because the
> 104-IDI-48 device features only input signals. Therefore, the dependence
> on the i8255 GPIO library is removed in this patch.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

(One nit-pick below)

> Suggested-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Signed-off-by: William Breathitt Gray <william.gray@xxxxxxxxxx>
> ---
> drivers/gpio/Kconfig | 2 +-
> drivers/gpio/gpio-104-idi-48.c | 97 +++++++---------------------------
> 2 files changed, 21 insertions(+), 78 deletions(-)
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index 6892979e511a..dd34039fc31b 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -873,7 +873,7 @@ config GPIO_104_IDI_48
> select ISA_BUS_API
> select REGMAP_IRQ
> select GPIOLIB_IRQCHIP
> - select GPIO_I8255
> + select GPIO_REGMAP
> help
> Enables GPIO support for the ACCES 104-IDI-48 family (104-IDI-48A,
> 104-IDI-48AC, 104-IDI-48B, 104-IDI-48BC). The base port addresses for
> diff --git a/drivers/gpio/gpio-104-idi-48.c b/drivers/gpio/gpio-104-idi-48.c
> index f77c05571062..2584f411ae67 100644
> --- a/drivers/gpio/gpio-104-idi-48.c
> +++ b/drivers/gpio/gpio-104-idi-48.c
> @@ -9,7 +9,7 @@
> #include <linux/bits.h>
> #include <linux/device.h>
> #include <linux/err.h>
> -#include <linux/gpio/driver.h>
> +#include <linux/gpio/regmap.h>
> #include <linux/interrupt.h>
> #include <linux/ioport.h>
> #include <linux/irq.h>
> @@ -20,10 +20,6 @@
> #include <linux/regmap.h>
> #include <linux/types.h>
>
> -#include "gpio-i8255.h"
> -
> -MODULE_IMPORT_NS(I8255);
> -
> #define IDI_48_EXTENT 8
> #define MAX_NUM_IDI_48 max_num_isa_dev(IDI_48_EXTENT)
>
> @@ -40,56 +36,17 @@ MODULE_PARM_DESC(irq, "ACCES 104-IDI-48 interrupt line numbers");
> #define IDI48_IRQ_STATUS 0x7
> #define IDI48_IRQ_ENABLE IDI48_IRQ_STATUS
>
> -/**
> - * struct idi_48_reg - device register structure
> - * @port0: Port 0 Inputs
> - * @unused: Unused
> - * @port1: Port 1 Inputs
> - * @irq: Read: IRQ Status Register/IRQ Clear
> - * Write: IRQ Enable/Disable
> - */
> -struct idi_48_reg {
> - u8 port0[3];
> - u8 unused;
> - u8 port1[3];
> - u8 irq;
> -};
> -
> -/**
> - * struct idi_48_gpio - GPIO device private data structure
> - * @chip: instance of the gpio_chip
> - * @reg: I/O address offset for the device registers
> - */
> -struct idi_48_gpio {
> - struct gpio_chip chip;
> - struct idi_48_reg __iomem *reg;
> -};
> -
> -static int idi_48_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
> -{
> - return GPIO_LINE_DIRECTION_IN;
> -}
> -
> -static int idi_48_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
> -{
> - return 0;
> -}
> -
> -static int idi_48_gpio_get(struct gpio_chip *chip, unsigned int offset)
> -{
> - struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
> - void __iomem *const ppi = idi48gpio->reg;
> -
> - return i8255_get(ppi, offset);
> -}
> -
> -static int idi_48_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
> - unsigned long *bits)
> +static int idi_48_reg_mask_xlate(struct gpio_regmap *gpio, unsigned int base,
> + unsigned int offset, unsigned int *reg,
> + unsigned int *mask)
> {
> - struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
> - void __iomem *const ppi = idi48gpio->reg;
> + const unsigned int line = offset % 8;
> + const unsigned int stride = offset / 8;
> + const unsigned int port = (stride / 3) * 4;
> + const unsigned int port_stride = stride % 3;
>
> - i8255_get_multiple(ppi, mask, bits, chip->ngpio);
> + *reg = base + port + port_stride;
> + *mask = BIT(line);
>
> return 0;
> }
> @@ -166,18 +123,14 @@ static const char *idi48_names[IDI48_NGPIO] = {
>
> static int idi_48_probe(struct device *dev, unsigned int id)
> {
> - struct idi_48_gpio *idi48gpio;
> const char *const name = dev_name(dev);
> + struct gpio_regmap_config config = {0};

{} will work in the same way.

> void __iomem *regs;
> struct regmap *map;
> struct regmap_irq_chip *chip;
> struct regmap_irq_chip_data *chip_data;
> int err;
>
> - idi48gpio = devm_kzalloc(dev, sizeof(*idi48gpio), GFP_KERNEL);
> - if (!idi48gpio)
> - return -ENOMEM;
> -
> if (!devm_request_region(dev, base[id], IDI_48_EXTENT, name)) {
> dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
> base[id], base[id] + IDI_48_EXTENT);
> @@ -187,7 +140,6 @@ static int idi_48_probe(struct device *dev, unsigned int id)
> regs = devm_ioport_map(dev, base[id], IDI_48_EXTENT);
> if (!regs)
> return -ENOMEM;
> - idi48gpio->reg = regs;
>
> map = devm_regmap_init_mmio(dev, regs, &idi48_regmap_config);
> if (IS_ERR(map))
> @@ -212,25 +164,16 @@ static int idi_48_probe(struct device *dev, unsigned int id)
> return err;
> }
>
> - idi48gpio->chip.label = name;
> - idi48gpio->chip.parent = dev;
> - idi48gpio->chip.owner = THIS_MODULE;
> - idi48gpio->chip.base = -1;
> - idi48gpio->chip.ngpio = IDI48_NGPIO;
> - idi48gpio->chip.names = idi48_names;
> - idi48gpio->chip.get_direction = idi_48_gpio_get_direction;
> - idi48gpio->chip.direction_input = idi_48_gpio_direction_input;
> - idi48gpio->chip.get = idi_48_gpio_get;
> - idi48gpio->chip.get_multiple = idi_48_gpio_get_multiple;
> -
> - err = devm_gpiochip_add_data(dev, &idi48gpio->chip, idi48gpio);
> - if (err) {
> - dev_err(dev, "GPIO registering failed (%d)\n", err);
> - return err;
> - }
> + config.parent = dev;
> + config.regmap = map;
> + config.ngpio = IDI48_NGPIO;
> + config.names = idi48_names;
> + config.reg_dat_base = GPIO_REGMAP_ADDR(0x0);
> + config.ngpio_per_reg = 8;
> + config.reg_mask_xlate = idi_48_reg_mask_xlate;
> + config.irq_domain = regmap_irq_get_domain(chip_data);
>
> - return gpiochip_irqchip_add_domain(&idi48gpio->chip,
> - regmap_irq_get_domain(chip_data));
> + return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &config));
> }
>
> static struct isa_driver idi_48_driver = {
> --
> 2.38.1
>

--
With Best Regards,
Andy Shevchenko