gpio: gpio-mm: Migrate to regmap API

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. The gpio-mm module is migrated to the new i8255
library interface leveraging the gpio-regmap API.
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

drivers/gpio/Kconfig

@@ -898,6 +898,7 @@ config GPIO_GPIO_MM
 	tristate "Diamond Systems GPIO-MM GPIO support"
 	depends on PC104
 	select ISA_BUS_API
+	select REGMAP_MMIO
 	select GPIO_I8255
 	help
 	  Enables GPIO support for the Diamond Systems GPIO-MM and GPIO-MM-12.

drivers/gpio/gpio-gpio-mm.c

@@ -8,13 +8,13 @@
  */
 #include <linux/device.h>
 #include <linux/errno.h>
-#include <linux/gpio/driver.h>
-#include <linux/io.h>
 #include <linux/ioport.h>
 #include <linux/isa.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
 
 #include "gpio-i8255.h"
 
@@ -30,83 +30,22 @@ MODULE_PARM_DESC(base, "Diamond Systems GPIO-MM base addresses");
 
 #define GPIOMM_NUM_PPI 2
 
-/**
- * struct gpiomm_gpio - GPIO device private data structure
- * @chip:		instance of the gpio_chip
- * @ppi_state:		Programmable Peripheral Interface group states
- * @ppi:		Programmable Peripheral Interface groups
- */
-struct gpiomm_gpio {
-	struct gpio_chip chip;
-	struct i8255_state ppi_state[GPIOMM_NUM_PPI];
-	struct i8255 __iomem *ppi;
+static const struct regmap_range gpiomm_volatile_ranges[] = {
+	i8255_volatile_regmap_range(0x0), i8255_volatile_regmap_range(0x4),
+};
+static const struct regmap_access_table gpiomm_volatile_table = {
+	.yes_ranges = gpiomm_volatile_ranges,
+	.n_yes_ranges = ARRAY_SIZE(gpiomm_volatile_ranges),
+};
+static const struct regmap_config gpiomm_regmap_config = {
+	.reg_bits = 8,
+	.reg_stride = 1,
+	.val_bits = 8,
+	.io_port = true,
+	.max_register = 0x7,
+	.volatile_table = &gpiomm_volatile_table,
+	.cache_type = REGCACHE_FLAT,
 };
-
-static int gpiomm_gpio_get_direction(struct gpio_chip *chip,
-	unsigned int offset)
-{
-	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
-
-	if (i8255_get_direction(gpiommgpio->ppi_state, offset))
-		return GPIO_LINE_DIRECTION_IN;
-
-	return GPIO_LINE_DIRECTION_OUT;
-}
-
-static int gpiomm_gpio_direction_input(struct gpio_chip *chip,
-	unsigned int offset)
-{
-	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
-
-	i8255_direction_input(gpiommgpio->ppi, gpiommgpio->ppi_state, offset);
-
-	return 0;
-}
-
-static int gpiomm_gpio_direction_output(struct gpio_chip *chip,
-	unsigned int offset, int value)
-{
-	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
-
-	i8255_direction_output(gpiommgpio->ppi, gpiommgpio->ppi_state, offset,
-			       value);
-
-	return 0;
-}
-
-static int gpiomm_gpio_get(struct gpio_chip *chip, unsigned int offset)
-{
-	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
-
-	return i8255_get(gpiommgpio->ppi, offset);
-}
-
-static int gpiomm_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
-	unsigned long *bits)
-{
-	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
-
-	i8255_get_multiple(gpiommgpio->ppi, mask, bits, chip->ngpio);
-
-	return 0;
-}
-
-static void gpiomm_gpio_set(struct gpio_chip *chip, unsigned int offset,
-	int value)
-{
-	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
-
-	i8255_set(gpiommgpio->ppi, gpiommgpio->ppi_state, offset, value);
-}
-
-static void gpiomm_gpio_set_multiple(struct gpio_chip *chip,
-	unsigned long *mask, unsigned long *bits)
-{
-	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
-
-	i8255_set_multiple(gpiommgpio->ppi, gpiommgpio->ppi_state, mask, bits,
-			   chip->ngpio);
-}
 
 #define GPIOMM_NGPIO 48
 static const char *gpiomm_names[GPIOMM_NGPIO] = {
@@ -120,30 +59,11 @@ static const char *gpiomm_names[GPIOMM_NGPIO] = {
 	"Port 2C2", "Port 2C3", "Port 2C4", "Port 2C5", "Port 2C6", "Port 2C7",
 };
 
-static void gpiomm_init_dio(struct i8255 __iomem *const ppi,
-			    struct i8255_state *const ppi_state)
-{
-	const unsigned long ngpio = 24;
-	const unsigned long mask = GENMASK(ngpio - 1, 0);
-	const unsigned long bits = 0;
-	unsigned long i;
-
-	/* Initialize all GPIO to output 0 */
-	for (i = 0; i < GPIOMM_NUM_PPI; i++) {
-		i8255_mode0_output(&ppi[i]);
-		i8255_set_multiple(&ppi[i], &ppi_state[i], &mask, &bits, ngpio);
-	}
-}
-
 static int gpiomm_probe(struct device *dev, unsigned int id)
 {
-	struct gpiomm_gpio *gpiommgpio;
 	const char *const name = dev_name(dev);
-	int err;
-
-	gpiommgpio = devm_kzalloc(dev, sizeof(*gpiommgpio), GFP_KERNEL);
-	if (!gpiommgpio)
-		return -ENOMEM;
+	struct i8255_regmap_config config = {};
+	void __iomem *regs;
 
 	if (!devm_request_region(dev, base[id], GPIOMM_EXTENT, name)) {
 		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
@@ -151,34 +71,20 @@ static int gpiomm_probe(struct device *dev, unsigned int id)
 		return -EBUSY;
 	}
 
-	gpiommgpio->ppi = devm_ioport_map(dev, base[id], GPIOMM_EXTENT);
-	if (!gpiommgpio->ppi)
+	regs = devm_ioport_map(dev, base[id], GPIOMM_EXTENT);
+	if (!regs)
 		return -ENOMEM;
 
-	gpiommgpio->chip.label = name;
-	gpiommgpio->chip.parent = dev;
-	gpiommgpio->chip.owner = THIS_MODULE;
-	gpiommgpio->chip.base = -1;
-	gpiommgpio->chip.ngpio = GPIOMM_NGPIO;
-	gpiommgpio->chip.names = gpiomm_names;
-	gpiommgpio->chip.get_direction = gpiomm_gpio_get_direction;
-	gpiommgpio->chip.direction_input = gpiomm_gpio_direction_input;
-	gpiommgpio->chip.direction_output = gpiomm_gpio_direction_output;
-	gpiommgpio->chip.get = gpiomm_gpio_get;
-	gpiommgpio->chip.get_multiple = gpiomm_gpio_get_multiple;
-	gpiommgpio->chip.set = gpiomm_gpio_set;
-	gpiommgpio->chip.set_multiple = gpiomm_gpio_set_multiple;
-
-	i8255_state_init(gpiommgpio->ppi_state, GPIOMM_NUM_PPI);
-	gpiomm_init_dio(gpiommgpio->ppi, gpiommgpio->ppi_state);
-
-	err = devm_gpiochip_add_data(dev, &gpiommgpio->chip, gpiommgpio);
-	if (err) {
-		dev_err(dev, "GPIO registering failed (%d)\n", err);
-		return err;
-	}
+	config.map = devm_regmap_init_mmio(dev, regs, &gpiomm_regmap_config);
+	if (IS_ERR(config.map))
+		return dev_err_probe(dev, PTR_ERR(config.map),
+				     "Unable to initialize register map\n");
+
+	config.parent = dev;
+	config.num_ppi = GPIOMM_NUM_PPI;
+	config.names = gpiomm_names;
 
-	return 0;
+	return devm_i8255_regmap_register(dev, &config);
 }
 
 static struct isa_driver gpiomm_driver = {