drivers: gpio: implement PALMAS GPIO cell

Add gpio driver for TI Palmas series PMIC. This has 8 gpio which can
work as input/output.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
diff --git a/drivers/gpio/palmas_gpio.c b/drivers/gpio/palmas_gpio.c
new file mode 100644
index 0000000..1503935
--- /dev/null
+++ b/drivers/gpio/palmas_gpio.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Based on mainline Linux palmas GPIO driver
+ * Copyright(C) 2023 Svyatoslav Ryhel <clamor95@gmail.com>
+ */
+
+#include <dm.h>
+#include <i2c.h>
+#include <asm/gpio.h>
+#include <power/palmas.h>
+
+#define NUM_GPIOS	8
+
+static int palmas_gpio_set_value(struct udevice *dev, unsigned int offset,
+				 int value)
+{
+	struct palmas_priv *priv = dev_get_priv(dev->parent);
+	u32 reg;
+	int ret;
+
+	reg = (value) ? PALMAS_GPIO_SET_DATA_OUT : PALMAS_GPIO_CLEAR_DATA_OUT;
+
+	ret = dm_i2c_reg_write(priv->chip2, reg, BIT(offset));
+	if (ret < 0)
+		log_debug("%s: Reg 0x%02x write failed, %d\n", __func__, reg, ret);
+
+	return ret;
+}
+
+static int palmas_gpio_get_value(struct udevice *dev, unsigned int offset)
+{
+	struct palmas_priv *priv = dev_get_priv(dev->parent);
+	u32 reg;
+	int ret;
+
+	ret = dm_i2c_reg_read(priv->chip2, PALMAS_GPIO_DATA_DIR);
+	if (ret < 0) {
+		log_debug("%s: GPIO_DATA_DIR read failed, %d\n", __func__, ret);
+		return ret;
+	}
+
+	if (ret & BIT(offset))
+		reg = PALMAS_GPIO_DATA_OUT;
+	else
+		reg = PALMAS_GPIO_DATA_IN;
+
+	ret = dm_i2c_reg_read(priv->chip2, reg);
+	if (ret < 0) {
+		log_debug("%s: Reg 0x%02x read failed, %d\n", __func__, reg, ret);
+		return ret;
+	}
+
+	return !!(ret & BIT(offset));
+}
+
+static int palmas_gpio_direction_input(struct udevice *dev, unsigned int offset)
+{
+	struct palmas_priv *priv = dev_get_priv(dev->parent);
+	int ret;
+
+	ret = dm_i2c_reg_clrset(priv->chip2, PALMAS_GPIO_DATA_DIR,
+				BIT(offset), 0);
+	if (ret < 0)
+		log_debug("%s: GPIO_DATA_DIR val update failed: %d\n", __func__, ret);
+
+	return ret;
+}
+
+static int palmas_gpio_direction_output(struct udevice *dev, unsigned int offset,
+					int value)
+{
+	struct palmas_priv *priv = dev_get_priv(dev->parent);
+	int ret;
+
+	/* Set the initial value */
+	palmas_gpio_set_value(dev, offset, value);
+
+	ret = dm_i2c_reg_clrset(priv->chip2, PALMAS_GPIO_DATA_DIR,
+				BIT(offset), BIT(offset));
+	if (ret < 0)
+		log_debug("%s: GPIO_DATA_DIR val update failed: %d\n", __func__, ret);
+
+	return ret;
+}
+
+static int palmas_gpio_get_function(struct udevice *dev, unsigned int offset)
+{
+	struct palmas_priv *priv = dev_get_priv(dev->parent);
+	int ret;
+
+	ret = dm_i2c_reg_read(priv->chip2, PALMAS_GPIO_DATA_DIR);
+	if (ret < 0) {
+		log_debug("%s: GPIO_DATA_DIR read failed, %d\n", __func__, ret);
+		return ret;
+	}
+
+	if (ret & BIT(offset))
+		return GPIOF_OUTPUT;
+	else
+		return GPIOF_INPUT;
+}
+
+static const struct dm_gpio_ops palmas_gpio_ops = {
+	.direction_input	= palmas_gpio_direction_input,
+	.direction_output	= palmas_gpio_direction_output,
+	.get_value		= palmas_gpio_get_value,
+	.set_value		= palmas_gpio_set_value,
+	.get_function		= palmas_gpio_get_function,
+};
+
+static int palmas_gpio_probe(struct udevice *dev)
+{
+	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+
+	uc_priv->gpio_count = NUM_GPIOS;
+	uc_priv->bank_name = "GPIO";
+
+	return 0;
+}
+
+static const struct udevice_id palmas_ids[] = {
+	{ .compatible = "ti,palmas-gpio" },
+	{ }
+};
+
+U_BOOT_DRIVER(palmas_gpio) = {
+	.name	= PALMAS_GPIO_DRIVER,
+	.id	= UCLASS_GPIO,
+	.of_match = palmas_ids,
+	.probe	= palmas_gpio_probe,
+	.ops	= &palmas_gpio_ops,
+};