[PATCH v1] drivers/gpio: add support for MAX7320 i2c i/o expander

* [PATCH v1] drivers/gpio: add support for MAX7320 i2c i/o expander
@ 2021-10-01 11:37 Hannes Schmelzer
  2021-10-01 13:52 ` Tom Rini
  2021-10-20  0:46 ` Tom Rini
  0 siblings, 2 replies; 4+ messages in thread
From: Hannes Schmelzer @ 2021-10-01 11:37 UTC (permalink / raw)
  To: U-Boot Mailing List
  Cc: Hannes Schmelzer, Harm Berntsen, Heiko Schocher, Linus Walleij,
	Michal Simek, Sebastian Reichel, Simon Glass, Stefan Roese,
	Stephan Gerhold, Weijie Gao

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

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

---

 doc/device-tree-bindings/gpio/gpio-max7320.txt |  36 ++++++++
 drivers/gpio/Kconfig                           |   8 ++
 drivers/gpio/Makefile                          |   1 +
 drivers/gpio/max7320_gpio.c                    | 113 +++++++++++++++++++++++++
 4 files changed, 158 insertions(+)
 create mode 100644 doc/device-tree-bindings/gpio/gpio-max7320.txt
 create mode 100644 drivers/gpio/max7320_gpio.c

diff --git a/doc/device-tree-bindings/gpio/gpio-max7320.txt b/doc/device-tree-bindings/gpio/gpio-max7320.txt
new file mode 100644
index 0000000..87b703b
--- /dev/null
+++ b/doc/device-tree-bindings/gpio/gpio-max7320.txt
@@ -0,0 +1,36 @@
+* MAX7320 I/O expanders
+
+The original maxim 7320 i/o expander offers 8 bit push/pull outputs.
+There exists some clones which offers 16 bit.
+
+Required Properties:
+
+  - compatible: should be one of the following.
+    - "maxim,max7320"
+
+  - reg: I2C slave address.
+
+  - gpio-controller: Marks the device node as a gpio controller.
+  - #gpio-cells: Should be 2. The first cell is the GPIO number and the second
+    cell specifies GPIO flags, as defined in <dt-bindings/gpio/gpio.h>. Only the
+    GPIO_ACTIVE_HIGH and GPIO_ACTIVE_LOW flags are supported.
+
+Optional Properties:
+
+   - ngpios: tell the driver how many gpios the device offers.
+     if the property is omitted, 8bit (original maxim) is assumed.
+
+Please refer to gpio.txt in this directory for details of the common GPIO
+bindings used by client devices.
+
+Example: MAX7320 I/O expander node
+
+	ledgpio: max7320@5d {
+		status = "okay";
+		compatible = "maxim,max7320";
+		reg = <0x5d>;
+		#gpio-cells = <2>;
+		gpio-controller;
+		ngpios = <16>;
+	};
+
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index e37ac9f..3aafbe3 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -513,4 +513,12 @@ config NOMADIK_GPIO
 	  into a number of banks each with 32 GPIOs. The GPIOs for a device are
 	  defined in the device tree with one node for each bank.
 
+config MAX7320_GPIO
+	bool "MAX7320 I2C GPIO Expander driver"
+	depends on DM_GPIO && DM_I2C
+	help
+	 Support for MAX7320 I2C 8/16-bit GPIO expander.
+	 original maxim device has 8 push/pull outputs,
+	 some clones offers 16bit.
+
 endmenu
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 58f4704..f59ea4a 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -69,3 +69,4 @@ obj-$(CONFIG_MSCC_SGPIO)	+= mscc_sgpio.o
 obj-$(CONFIG_NX_GPIO)		+= nx_gpio.o
 obj-$(CONFIG_SIFIVE_GPIO)	+= sifive-gpio.o
 obj-$(CONFIG_NOMADIK_GPIO)	+= nmk_gpio.o
+obj-$(CONFIG_MAX7320_GPIO)	+= max7320_gpio.o
diff --git a/drivers/gpio/max7320_gpio.c b/drivers/gpio/max7320_gpio.c
new file mode 100644
index 0000000..647aed9
--- /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),
+};
-- 
2.7.4



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