gpio: gpio-adg1414: new driver

The ADG1414 is a 9.5 Ω RON ±15 V/+12 V/±5 V iCMOS Serially-Controlled
Octal SPST Switches

Signed-off-by: Kim Seer Paller <kimseer.paller@analog.com>

Author: kseerp

drivers/gpio/Kconfig

@@ -1606,6 +1606,16 @@ config GPIO_74X164
 	  shift registers. This driver can be used to provide access
 	  to more GPIO outputs.
 
+config GPIO_ADG1414
+	tristate "ADG1414 SPST Switch Driver"
+	depends on GPIOLIB && SPI
+	help
+	  Say yes here to build support for Analog Devices ADG1414 SPST
+	  Switch Driver
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called gpio-adg1414.
+
 config GPIO_ADI_DAQ1
 	tristate "Analog Devices AD-FMCDAQ1-EBZ SPI-GPIO expander driver"
 	help

drivers/gpio/Makefile

@@ -23,6 +23,7 @@ obj-$(CONFIG_GPIO_104_IDI_48)		+= gpio-104-idi-48.o
 obj-$(CONFIG_GPIO_104_IDIO_16)		+= gpio-104-idio-16.o
 obj-$(CONFIG_GPIO_74X164)		+= gpio-74x164.o
 obj-$(CONFIG_GPIO_74XX_MMIO)		+= gpio-74xx-mmio.o
+obj-$(CONFIG_GPIO_ADG1414)		+= gpio-adg1414.o
 obj-$(CONFIG_GPIO_ADI_DAQ1)		+= gpio-adi-daq1.o
 obj-$(CONFIG_GPIO_ADNP)			+= gpio-adnp.o
 obj-$(CONFIG_GPIO_ADP5520)		+= gpio-adp5520.o

drivers/gpio/gpio-adg1414.c

@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ADG1414 SPST Switch Driver
+ *
+ * Copyright 2023 Analog Devices Inc.
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/spi/spi.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/property.h>
+
+/*
+ * Definition used because the latter is not available
+ * in project's source tree.
+ */
+#define GPIO_DMA_MINALIGN		ARCH_KMALLOC_MINALIGN
+
+struct adg1414_state {
+	struct spi_device		*spi;
+	struct gpio_chip		chip;
+	struct mutex			lock; /* protect sensor state */
+	u8				buffer[32];
+
+	__be32				tx __aligned(GPIO_DMA_MINALIGN);
+};
+
+static void adg1414_set(struct gpio_chip *chip,
+			unsigned int offset,
+			int value)
+{
+	struct adg1414_state *st = gpiochip_get_data(chip);
+	int ret, i;
+	u32 tx = 0;
+
+	struct spi_transfer xfer = {
+		.tx_buf = &st->tx,
+		.len = st->chip.ngpio / 8,
+	};
+
+	st->buffer[offset] = value;
+
+	for (i = 0; i < st->chip.ngpio; i++)
+		tx |= st->buffer[i] << i;
+
+	st->tx = cpu_to_be32(tx << (32 - st->chip.ngpio));
+
+	mutex_lock(&st->lock);
+
+	ret = spi_sync_transfer(st->spi, &xfer, 1);
+	if (ret)
+		goto out;
+
+out:
+	mutex_unlock(&st->lock);
+}
+
+static int adg1414_get(struct gpio_chip *chip,
+		       unsigned int offset)
+{
+	struct adg1414_state *st = gpiochip_get_data(chip);
+
+	return st->buffer[offset];
+}
+
+static int adg1414_get_direction(struct gpio_chip *chip,
+				 unsigned int offset)
+{
+	return GPIO_LINE_DIRECTION_OUT;
+}
+
+static int adg1414_probe(struct spi_device *spi)
+{
+	struct adg1414_state *st;
+	struct gpio_desc *reset;
+	struct device *dev = &spi->dev;
+	u32 num_devices;
+	int ret;
+
+	st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
+	if (!st)
+		return -ENOMEM;
+
+	st->spi = spi;
+
+	/* Use reset pin to reset the device */
+	reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(reset))
+		return dev_err_probe(dev, PTR_ERR(reset), "Failed to get reset gpio");
+
+	if (reset) {
+		ndelay(15);
+		gpiod_set_value_cansleep(reset, 1);
+	}
+
+	num_devices = 1;
+	ret = device_property_read_u32(dev, "daisy-chained-devices",
+				       &num_devices);
+	if (!ret) {
+		if (num_devices > 4 || num_devices < 1)
+			return dev_err_probe(dev, ret,
+				"Failed to get daisy-chained-devices property\n");
+	}
+
+	st->chip.label = "adg1414";
+	st->chip.parent = dev;
+	st->chip.owner = THIS_MODULE;
+	st->chip.get_direction = adg1414_get_direction;
+	st->chip.set = adg1414_set;
+	st->chip.get = adg1414_get;
+	st->chip.base = -1;
+	st->chip.ngpio =  num_devices * 8;
+	st->chip.can_sleep = true;
+
+	mutex_init(&st->lock);
+
+	return devm_gpiochip_add_data(dev, &st->chip, st);
+}
+
+static const struct of_device_id adg1414_of_match[] = {
+	{ .compatible = "adi,adg1414" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, adg1414_of_match);
+
+static struct spi_driver adg1414_driver = {
+	.driver = {
+		.name = "adg1414",
+		.of_match_table = adg1414_of_match,
+	},
+	.probe = adg1414_probe,
+};
+module_spi_driver(adg1414_driver);
+
+MODULE_AUTHOR("Kim Seer Paller <kimseer.paller@analog.com>");
+MODULE_DESCRIPTION("ADG1414 SPST Switch Driver");
+MODULE_LICENSE("GPL");