gpio: wcd934x: Add support to wcd934x gpio controller

This patch adds support to wcd934x gpio block found in
WCD9340/WC9341 Audio codecs.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200107130844.20763-3-srinivas.kandagatla@linaro.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -619,6 +619,13 @@ config GPIO_VX855
 	  additional drivers must be enabled in order to use the
 	  functionality of the device.
 
+config GPIO_WCD934X
+	tristate "Qualcomm Technologies Inc WCD9340/WCD9341 gpio controller driver"
+	depends on MFD_WCD934X && OF_GPIO
+	help
+         This driver is to supprot GPIO block found on the Qualcomm Technologies
+	 Inc WCD9340/WCD9341 Audio Codec.
+
 config GPIO_XGENE
 	bool "APM X-Gene GPIO controller support"
 	depends on ARM64 && OF_GPIO

drivers/gpio/Makefile

@@ -158,6 +158,7 @@ obj-$(CONFIG_GPIO_VF610)		+= gpio-vf610.o
 obj-$(CONFIG_GPIO_VIPERBOARD)		+= gpio-viperboard.o
 obj-$(CONFIG_GPIO_VR41XX)		+= gpio-vr41xx.o
 obj-$(CONFIG_GPIO_VX855)		+= gpio-vx855.o
+obj-$(CONFIG_GPIO_WCD934X)		+= gpio-wcd934x.o
 obj-$(CONFIG_GPIO_WHISKEY_COVE)		+= gpio-wcove.o
 obj-$(CONFIG_GPIO_WINBOND)		+= gpio-winbond.o
 obj-$(CONFIG_GPIO_WM831X)		+= gpio-wm831x.o

drivers/gpio/gpio-wcd934x.c

@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019, Linaro Limited
+
+#include <linux/module.h>
+#include <linux/gpio/driver.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/of_device.h>
+
+#define WCD_PIN_MASK(p) BIT(p - 1)
+#define WCD_REG_DIR_CTL_OFFSET 0x42
+#define WCD_REG_VAL_CTL_OFFSET 0x43
+#define WCD934X_NPINS		5
+
+struct wcd_gpio_data {
+	struct regmap *map;
+	struct gpio_chip chip;
+};
+
+static int wcd_gpio_get_direction(struct gpio_chip *chip, unsigned int pin)
+{
+	struct wcd_gpio_data *data = gpiochip_get_data(chip);
+	unsigned int value;
+	int ret;
+
+	ret = regmap_read(data->map, WCD_REG_DIR_CTL_OFFSET, &value);
+	if (ret < 0)
+		return ret;
+
+	if (value & WCD_PIN_MASK(pin))
+		return GPIO_LINE_DIRECTION_OUT;
+
+	return GPIO_LINE_DIRECTION_IN;
+}
+
+static int wcd_gpio_direction_input(struct gpio_chip *chip, unsigned int pin)
+{
+	struct wcd_gpio_data *data = gpiochip_get_data(chip);
+
+	return regmap_update_bits(data->map, WCD_REG_DIR_CTL_OFFSET,
+				  WCD_PIN_MASK(pin), 0);
+}
+
+static int wcd_gpio_direction_output(struct gpio_chip *chip, unsigned int pin,
+				     int val)
+{
+	struct wcd_gpio_data *data = gpiochip_get_data(chip);
+
+	regmap_update_bits(data->map, WCD_REG_DIR_CTL_OFFSET,
+			   WCD_PIN_MASK(pin), WCD_PIN_MASK(pin));
+
+	return regmap_update_bits(data->map, WCD_REG_VAL_CTL_OFFSET,
+				  WCD_PIN_MASK(pin),
+				  val ? WCD_PIN_MASK(pin) : 0);
+}
+
+static int wcd_gpio_get(struct gpio_chip *chip, unsigned int pin)
+{
+	struct wcd_gpio_data *data = gpiochip_get_data(chip);
+	int value;
+
+	regmap_read(data->map, WCD_REG_VAL_CTL_OFFSET, &value);
+
+	return !!(value && WCD_PIN_MASK(pin));
+}
+
+static void wcd_gpio_set(struct gpio_chip *chip, unsigned int pin, int val)
+{
+	wcd_gpio_direction_output(chip, pin, val);
+}
+
+static int wcd_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct wcd_gpio_data *data;
+	struct gpio_chip *chip;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->map = dev_get_regmap(dev->parent, NULL);
+	if (!data->map) {
+		dev_err(dev, "%s: failed to get regmap\n", __func__);
+		return  -EINVAL;
+	}
+
+	chip = &data->chip;
+	chip->direction_input  = wcd_gpio_direction_input;
+	chip->direction_output = wcd_gpio_direction_output;
+	chip->get_direction = wcd_gpio_get_direction;
+	chip->get = wcd_gpio_get;
+	chip->set = wcd_gpio_set;
+	chip->parent = dev;
+	chip->base = -1;
+	chip->ngpio = WCD934X_NPINS;
+	chip->label = dev_name(dev);
+	chip->of_gpio_n_cells = 2;
+	chip->can_sleep = false;
+
+	return devm_gpiochip_add_data(dev, chip, data);
+}
+
+static const struct of_device_id wcd_gpio_of_match[] = {
+	{ .compatible = "qcom,wcd9340-gpio" },
+	{ .compatible = "qcom,wcd9341-gpio" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, wcd_gpio_of_match);
+
+static struct platform_driver wcd_gpio_driver = {
+	.driver = {
+		   .name = "wcd934x-gpio",
+		   .of_match_table = wcd_gpio_of_match,
+	},
+	.probe = wcd_gpio_probe,
+};
+
+module_platform_driver(wcd_gpio_driver);
+MODULE_DESCRIPTION("Qualcomm Technologies, Inc WCD GPIO control driver");
+MODULE_LICENSE("GPL v2");