gpio: mcp230xx: Introduce new driver

Introduce driver for I2C based MCP230xx GPIO chips, which are
quite common and already well supported by the Linux kernel.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 235 insertions, 0 deletions

diff --git a/drivers/gpio/mcp230xx_gpio.c b/drivers/gpio/mcp230xx_gpio.c
new file mode 100644
index 00000000000..9f02fd42b35
--- /dev/null
+++ b/drivers/gpio/mcp230xx_gpio.c
@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021, Collabora Ltd.
+ * Copyright (C) 2021, General Electric Company
+ * Author(s): Sebastian Reichel <sebastian.reichel@collabora.com>
+ */
+
+#define LOG_CATEGORY UCLASS_GPIO
+
+#include <common.h>
+#include <errno.h>
+#include <dm.h>
+#include <i2c.h>
+#include <asm/gpio.h>
+#include <dm/device_compat.h>
+#include <dt-bindings/gpio/gpio.h>
+
+enum mcp230xx_type {
+	UNKNOWN = 0,
+	MCP23008,
+	MCP23017,
+	MCP23018,
+};
+
+#define MCP230XX_IODIR 0x00
+#define MCP230XX_GPPU 0x06
+#define MCP230XX_GPIO 0x09
+#define MCP230XX_OLAT 0x0a
+
+#define BANKSIZE 8
+
+static int mcp230xx_read(struct udevice *dev, uint reg, uint offset)
+{
+	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+	int bank = offset / BANKSIZE;
+	int mask = 1 << (offset % BANKSIZE);
+	int shift = (uc_priv->gpio_count / BANKSIZE) - 1;
+	int ret;
+
+	ret = dm_i2c_reg_read(dev, (reg << shift) | bank);
+	if (ret < 0)
+		return ret;
+
+	return !!(ret & mask);
+}
+
+static int mcp230xx_write(struct udevice *dev, uint reg, uint offset, bool val)
+{
+	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+	int bank = offset / BANKSIZE;
+	int mask = 1 << (offset % BANKSIZE);
+	int shift = (uc_priv->gpio_count / BANKSIZE) - 1;
+
+	return dm_i2c_reg_clrset(dev, (reg << shift) | bank, mask, val ? mask : 0);
+}
+
+static int mcp230xx_get_value(struct udevice *dev, uint offset)
+{
+	int ret;
+
+	ret = mcp230xx_read(dev, MCP230XX_GPIO, offset);
+	if (ret < 0) {
+		dev_err(dev, "%s error: %d\n", __func__, ret);
+		return ret;
+	}
+
+	return ret;
+}
+
+static int mcp230xx_set_value(struct udevice *dev, uint offset, int val)
+{
+	int ret;
+
+	ret = mcp230xx_write(dev, MCP230XX_GPIO, offset, val);
+	if (ret < 0) {
+		dev_err(dev, "%s error: %d\n", __func__, ret);
+		return ret;
+	}
+
+	return ret;
+}
+
+static int mcp230xx_get_flags(struct udevice *dev, unsigned int offset,
+				  ulong *flags)
+{
+	int direction, pullup;
+
+	pullup = mcp230xx_read(dev, MCP230XX_GPPU, offset);
+	if (pullup < 0) {
+		dev_err(dev, "%s error: %d\n", __func__, pullup);
+		return pullup;
+	}
+
+	direction = mcp230xx_read(dev, MCP230XX_IODIR, offset);
+	if (direction < 0) {
+		dev_err(dev, "%s error: %d\n", __func__, direction);
+		return direction;
+	}
+
+	*flags = direction ? GPIOD_IS_IN : GPIOD_IS_OUT;
+
+	if (pullup)
+		*flags |= GPIOD_PULL_UP;
+
+	return 0;
+}
+
+static int mcp230xx_set_flags(struct udevice *dev, uint offset, ulong flags)
+{
+	bool input = !(flags & (GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE));
+	bool pullup = flags & GPIOD_PULL_UP;
+	ulong supported_mask;
+	int ret;
+
+	/* Note: active-low is ignored (handled by core) */
+	supported_mask = GPIOD_ACTIVE_LOW | GPIOD_MASK_DIR | GPIOD_PULL_UP;
+	if (flags & ~supported_mask) {
+		dev_err(dev, "%s unsupported flag(s): %lx\n", __func__, flags);
+		return -EINVAL;
+	}
+
+	ret = mcp230xx_write(dev, MCP230XX_OLAT, offset, !!(flags & GPIOD_IS_OUT_ACTIVE));
+	if (ret) {
+		dev_err(dev, "%s failed to setup output latch: %d\n", __func__, ret);
+		return ret;
+	}
+
+	ret = mcp230xx_write(dev, MCP230XX_GPPU, offset, pullup);
+	if (ret) {
+		dev_err(dev, "%s failed to setup pull-up: %d\n", __func__, ret);
+		return ret;
+	}
+
+	ret = mcp230xx_write(dev, MCP230XX_IODIR, offset, input);
+	if (ret) {
+		dev_err(dev, "%s failed to setup direction: %d\n", __func__, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int mcp230xx_direction_input(struct udevice *dev, uint offset)
+{
+	return mcp230xx_set_flags(dev, offset, GPIOD_IS_IN);
+}
+
+static int mcp230xx_direction_output(struct udevice *dev, uint offset, int val)
+{
+	int ret = mcp230xx_set_value(dev, offset, val);
+	if (ret < 0) {
+		dev_err(dev, "%s error: %d\n", __func__, ret);
+		return ret;
+	}
+	return mcp230xx_set_flags(dev, offset, GPIOD_IS_OUT);
+}
+
+static int mcp230xx_get_function(struct udevice *dev, uint offset)
+{
+	int ret;
+
+	ret = mcp230xx_read(dev, MCP230XX_IODIR, offset);
+	if (ret < 0) {
+		dev_err(dev, "%s error: %d\n", __func__, ret);
+		return ret;
+	}
+
+	return ret ? GPIOF_INPUT : GPIOF_OUTPUT;
+}
+
+static const struct dm_gpio_ops mcp230xx_ops = {
+	.direction_input	= mcp230xx_direction_input,
+	.direction_output	= mcp230xx_direction_output,
+	.get_value		= mcp230xx_get_value,
+	.set_value		= mcp230xx_set_value,
+	.get_function		= mcp230xx_get_function,
+	.set_flags		= mcp230xx_set_flags,
+	.get_flags		= mcp230xx_get_flags,
+};
+
+static int mcp230xx_probe(struct udevice *dev)
+{
+	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+	char name[32], label[8], *str;
+	int addr, gpio_count, size;
+	const u8 *tmp;
+
+	switch (dev_get_driver_data(dev)) {
+	case MCP23008:
+		gpio_count = 8;
+		break;
+	case MCP23017:
+	case MCP23018:
+		gpio_count = 16;
+		break;
+	default:
+		return -ENODEV;
+	}
+
+	addr = dev_read_addr(dev);
+	tmp = dev_read_prop(dev, "label", &size);
+	if (tmp) {
+		memcpy(label, tmp, sizeof(label) - 1);
+		label[sizeof(label) - 1] = '\0';
+		snprintf(name, sizeof(name), "%s@%x_", label, addr);
+	} else {
+		snprintf(name, sizeof(name), "gpio@%x_", addr);
+	}
+
+	str = strdup(name);
+	if (!str)
+		return -ENOMEM;
+
+	uc_priv->bank_name = str;
+	uc_priv->gpio_count = gpio_count;
+
+	dev_dbg(dev, "%s is ready\n", str);
+
+	return 0;
+}
+
+static const struct udevice_id mcp230xx_ids[] = {
+	{ .compatible = "microchip,mcp23008", .data = MCP23008, },
+	{ .compatible = "microchip,mcp23017", .data = MCP23017, },
+	{ .compatible = "microchip,mcp23018", .data = MCP23018, },
+	{ }
+};
+
+U_BOOT_DRIVER(mcp230xx) = {
+	.name		= "mcp230xx",
+	.id		= UCLASS_GPIO,
+	.ops		= &mcp230xx_ops,
+	.probe		= mcp230xx_probe,
+	.of_match	= mcp230xx_ids,
+};