gpio: ds4520: Add ADI DS4520 GPIO Expander Support

The DS4520 is a 9-bit nonvolatile (NV) I/O expander.
It offers users a digitally programmable alternative
to hardware jumpers and mechanical switches that are
being used to control digital logic node.

Signed-off-by: Okan Sahin <okan.sahin@analog.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 61a8d07..c5324e4 100644 (file)
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1029,6 +1029,17 @@ config GPIO_FXL6408
          To compile this driver as a module, choose M here: the module will
          be called gpio-fxl6408.
 
+config GPIO_DS4520
+       tristate "DS4520 I2C GPIO expander"
+       select REGMAP_I2C
+       select GPIO_REGMAP
+       help
+         GPIO driver for ADI DS4520 I2C-based GPIO expander.
+         Say yes here to enable the GPIO driver for the ADI DS4520 chip.
+
+         To compile this driver as a module, choose M here: the module will
+         be called gpio-ds4520.
+
 config GPIO_GW_PLD
        tristate "Gateworks PLD GPIO Expander"
        depends on OF_GPIO

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index c3ac51d..eb73b5d 100644 (file)
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -52,6 +52,7 @@ obj-$(CONFIG_GPIO_DA9052)             += gpio-da9052.o
 obj-$(CONFIG_GPIO_DA9055)              += gpio-da9055.o
 obj-$(CONFIG_GPIO_DAVINCI)             += gpio-davinci.o
 obj-$(CONFIG_GPIO_DLN2)                        += gpio-dln2.o
+obj-$(CONFIG_GPIO_DS4520)              += gpio-ds4520.o
 obj-$(CONFIG_GPIO_DWAPB)               += gpio-dwapb.o
 obj-$(CONFIG_GPIO_EIC_SPRD)            += gpio-eic-sprd.o
 obj-$(CONFIG_GPIO_ELKHARTLAKE)         += gpio-elkhartlake.o

diff --git a/drivers/gpio/gpio-ds4520.c b/drivers/gpio/gpio-ds4520.c
new file mode 100644 (file)
index 0000000..1903dea
--- /dev/null
+++ b/drivers/gpio/gpio-ds4520.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2023 Analog Devices, Inc.
+ * Driver for the DS4520 I/O Expander
+ */
+
+#include <linux/device.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/regmap.h>
+#include <linux/i2c.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#define DS4520_PULLUP0         0xF0
+#define DS4520_IO_CONTROL0     0xF2
+#define DS4520_IO_STATUS0      0xF8
+
+static const struct regmap_config ds4520_regmap_config = {
+       .reg_bits = 8,
+       .val_bits = 8,
+};
+
+static int ds4520_gpio_probe(struct i2c_client *client)
+{
+       struct gpio_regmap_config config = { };
+       struct device *dev = &client->dev;
+       struct regmap *regmap;
+       u32 ngpio;
+       u32 base;
+       int ret;
+
+       ret = device_property_read_u32(dev, "reg", &base);
+       if (ret)
+               return dev_err_probe(dev, ret, "Missing 'reg' property.\n");
+
+       ret = device_property_read_u32(dev, "ngpios", &ngpio);
+       if (ret)
+               return dev_err_probe(dev, ret, "Missing 'ngpios' property.\n");
+
+       regmap = devm_regmap_init_i2c(client, &ds4520_regmap_config);
+       if (IS_ERR(regmap))
+               return dev_err_probe(dev, PTR_ERR(regmap),
+                                    "Failed to allocate register map\n");
+
+       config.regmap = regmap;
+       config.parent = dev;
+       config.ngpio = ngpio;
+
+       config.reg_dat_base = base + DS4520_IO_STATUS0;
+       config.reg_set_base = base + DS4520_PULLUP0;
+       config.reg_dir_out_base = base + DS4520_IO_CONTROL0;
+
+       return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &config));
+}
+
+static const struct of_device_id ds4520_gpio_of_match_table[] = {
+       { .compatible = "adi,ds4520-gpio" },
+       { }
+};
+MODULE_DEVICE_TABLE(of, ds4520_gpio_of_match_table);
+
+static const struct i2c_device_id ds4520_gpio_id_table[] = {
+       { "ds4520-gpio" },
+       { }
+};
+MODULE_DEVICE_TABLE(i2c, ds4520_gpio_id_table);
+
+static struct i2c_driver ds4520_gpio_driver = {
+       .driver = {
+               .name = "ds4520-gpio",
+               .of_match_table = ds4520_gpio_of_match_table,
+       },
+       .probe = ds4520_gpio_probe,
+       .id_table = ds4520_gpio_id_table,
+};
+module_i2c_driver(ds4520_gpio_driver);
+
+MODULE_DESCRIPTION("DS4520 I/O Expander");
+MODULE_AUTHOR("Okan Sahin <okan.sahin@analog.com>");
+MODULE_LICENSE("GPL");