drivers/gpio: add support for MAX7320 i2c i/o expander

This commit adds support for the MAX7320 (and clones) gpio expander.

Signed-off-by: Hannes Schmelzer <hannes.schmelzer@br-automation.com>

1 files changed, 113 insertions, 0 deletions

diff --git a/drivers/gpio/max7320_gpio.c b/drivers/gpio/max7320_gpio.c
new file mode 100644
index 0000000000..647aed907b
--- /dev/null
+++ b/drivers/gpio/max7320_gpio.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * max7320 I2C GPIO EXPANDER DRIVER
+ *
+ * Copyright (C) 2021 Hannes Schmelzer <oe5hpm@oevsv.at>
+ * B&R Industrial Automation GmbH - http://www.br-automation.com
+ *
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <i2c.h>
+#include <asm-generic/gpio.h>
+#include <linux/bitops.h>
+
+struct max7320_chip {
+	u32 outreg;
+};
+
+static int max7320_direction_output(struct udevice *dev,
+				    unsigned int offset, int value)
+{
+	struct max7320_chip *plat = dev_get_plat(dev);
+	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+	struct dm_i2c_chip *chip = dev_get_parent_plat(dev);
+
+	int ret;
+
+	if (value)
+		plat->outreg |= BIT(offset);
+	else
+		plat->outreg &= ~BIT(offset);
+
+	ret = dm_i2c_write(dev,
+			   plat->outreg & 0xff,
+			   (uint8_t *)&plat->outreg + 1,
+			   uc_priv->gpio_count > 8 ? 1 : 0);
+	if (ret)
+		printf("%s i2c write failed to addr %x\n", __func__,
+		       chip->chip_addr);
+
+	return ret;
+}
+
+static int max7320_get_value(struct udevice *dev, unsigned int offset)
+{
+	struct max7320_chip *plat = dev_get_plat(dev);
+
+	return (plat->outreg >> offset) & 0x1;
+}
+
+static int max7320_set_value(struct udevice *dev, unsigned int offset,
+			     int value)
+{
+	return max7320_direction_output(dev, offset, value);
+}
+
+static int max7320_get_function(struct udevice *dev, unsigned int offset)
+{
+	return GPIOF_OUTPUT;
+}
+
+static int max7320_ofdata_plat(struct udevice *dev)
+{
+	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+
+	uc_priv->gpio_count = dev_read_u32_default(dev, "ngpios", 8);
+	if (uc_priv->gpio_count > 16) {
+		printf("%s: max7320 doesn't support more than 16 gpios!",
+		       __func__);
+		return -EINVAL;
+	}
+
+	uc_priv->bank_name = fdt_getprop(gd->fdt_blob, dev_of_offset(dev),
+					 "gpio-bank-name", NULL);
+	if (!uc_priv->bank_name)
+		uc_priv->bank_name = fdt_get_name(gd->fdt_blob,
+						  dev_of_offset(dev), NULL);
+
+	return 0;
+}
+
+static int max7320_gpio_probe(struct udevice  *dev)
+{
+	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+
+	debug("%s GPIO controller with %d gpios probed\n",
+	      uc_priv->bank_name, uc_priv->gpio_count);
+
+	return 0;
+}
+
+static const struct dm_gpio_ops max7320_gpio_ops = {
+	.direction_output	= max7320_direction_output,
+	.set_value		= max7320_set_value,
+	.get_value		= max7320_get_value,
+	.get_function		= max7320_get_function,
+};
+
+static const struct udevice_id max7320_gpio_ids[] = {
+	{ .compatible = "maxim,max7320" },
+	{ }
+};
+
+U_BOOT_DRIVER(gpio_max7320) = {
+	.name		= "gpio_max7320",
+	.id		= UCLASS_GPIO,
+	.ops		= &max7320_gpio_ops,
+	.of_match	= max7320_gpio_ids,
+	.of_to_plat	= max7320_ofdata_plat,
+	.probe		= max7320_gpio_probe,
+	.plat_auto	= sizeof(struct max7320_chip),
+};