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>

diff --git a/doc/device-tree-bindings/gpio/gpio-max7320.txt b/doc/device-tree-bindings/gpio/gpio-max7320.txt
new file mode 100644 (file)
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 f0439e2..40abc33 100644 (file)
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -183,6 +183,14 @@ config LPC32XX_GPIO
        help
          Support for the LPC32XX GPIO driver.
 
+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.
+
 config MCP230XX_GPIO
        bool "MCP230XX GPIO driver"
        depends on DM

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index a9dc546..3c851b3 100644 (file)
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -68,3 +68,4 @@ 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 (file)
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),
+};