[PATCH v8 10/12] mux: adg792a: add mux controller driver for ADG792A/G

[Peter Rosin <peda@axentia.se>]

Analog Devices ADG792A/G is a triple 4:1 mux.

Reviewed-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/mux/Kconfig       |  12 ++++
 drivers/mux/Makefile      |   1 +
 drivers/mux/mux-adg792a.c | 167 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 180 insertions(+)
 create mode 100644 drivers/mux/mux-adg792a.c

diff --git a/drivers/mux/Kconfig b/drivers/mux/Kconfig
index 57e6f4e5fda9..d13fcf98958e 100644
--- a/drivers/mux/Kconfig
+++ b/drivers/mux/Kconfig
@@ -16,6 +16,18 @@ menuconfig MULTIPLEXER
 
 if MULTIPLEXER
 
+config MUX_ADG792A
+	tristate "Analog Devices ADG792A/ADG792G Multiplexers"
+	depends on I2C
+	help
+	  ADG792A and ADG792G Wide Bandwidth Triple 4:1 Multiplexers
+
+	  The driver supports both operating the three multiplexers in
+	  parallel and operating them independently.
+
+	  To compile the driver as a module, choose M here: the module will
+	  be called mux-adg792a.
+
 config MUX_GPIO
 	tristate "GPIO-controlled Multiplexer"
 	depends on OF && GPIOLIB
diff --git a/drivers/mux/Makefile b/drivers/mux/Makefile
index facc43da3648..fddbb073fc77 100644
--- a/drivers/mux/Makefile
+++ b/drivers/mux/Makefile
@@ -3,4 +3,5 @@
 #
 
 obj-$(CONFIG_MULTIPLEXER)      	+= mux-core.o
+obj-$(CONFIG_MUX_ADG792A)	+= mux-adg792a.o
 obj-$(CONFIG_MUX_GPIO)		+= mux-gpio.o
diff --git a/drivers/mux/mux-adg792a.c b/drivers/mux/mux-adg792a.c
new file mode 100644
index 000000000000..6a4c4c9f585b
--- /dev/null
+++ b/drivers/mux/mux-adg792a.c
@@ -0,0 +1,167 @@
+/*
+ * Multiplexer driver for Analog Devices ADG792A/G Triple 4:1 mux
+ *
+ * Copyright (C) 2017 Axentia Technologies AB
+ *
+ * Author: Peter Rosin <peda@axentia.se>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/mux.h>
+
+#define ADG792A_LDSW		BIT(0)
+#define ADG792A_RESET		BIT(1)
+#define ADG792A_DISABLE(mux)	(0x50 | (mux))
+#define ADG792A_DISABLE_ALL	(0x5f)
+#define ADG792A_MUX(mux, state)	(0xc0 | (((mux) + 1) << 2) | (state))
+#define ADG792A_MUX_ALL(state)	(0xc0 | (state))
+
+#define ADG792A_DISABLE_STATE	(4)
+
+static int adg792a_set(struct mux_control *mux, int state)
+{
+	struct i2c_client *i2c = to_i2c_client(mux->chip->dev.parent);
+	u8 cmd;
+
+	if (mux->chip->controllers == 1) {
+		/* parallel mux controller operation */
+		if (state == ADG792A_DISABLE_STATE)
+			cmd = ADG792A_DISABLE_ALL;
+		else
+			cmd = ADG792A_MUX_ALL(state);
+	} else {
+		unsigned int controller = mux_control_get_index(mux);
+
+		if (state == ADG792A_DISABLE_STATE)
+			cmd = ADG792A_DISABLE(controller);
+		else
+			cmd = ADG792A_MUX(controller, state);
+	}
+
+	return i2c_smbus_write_byte_data(i2c, cmd, ADG792A_LDSW);
+}
+
+static const struct mux_control_ops adg792a_ops = {
+	.set = adg792a_set,
+};
+
+static int adg792a_probe(struct i2c_client *i2c,
+			 const struct i2c_device_id *id)
+{
+	struct device *dev = &i2c->dev;
+	struct mux_chip *mux_chip;
+	bool parallel;
+	int count;
+	int ret;
+	int i;
+
+	parallel = of_property_read_bool(i2c->dev.of_node, "adi,parallel");
+
+	mux_chip = devm_mux_chip_alloc(dev, parallel ? 1 : 3, 0);
+	if (!mux_chip)
+		return -ENOMEM;
+
+	mux_chip->ops = &adg792a_ops;
+
+	ret = i2c_smbus_write_byte_data(i2c, ADG792A_DISABLE_ALL,
+					ADG792A_RESET | ADG792A_LDSW);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < mux_chip->controllers; ++i) {
+		struct mux_control *mux = &mux_chip->mux[i];
+
+		mux->states = 4;
+	}
+
+	count = of_property_count_u32_elems(dev->of_node, "adi,idle-state");
+	for (i = 0; i < count; i += 2) {
+		u32 index;
+		u32 idle_state;
+
+		ret = of_property_read_u32_index(dev->of_node,
+						 "adi,idle-state", i,
+						 &index);
+		if (ret < 0)
+			return ret;
+		if (index >= mux_chip->controllers) {
+			dev_err(dev, "invalid mux %u\n", index);
+			return -EINVAL;
+		}
+
+		ret = of_property_read_u32_index(dev->of_node,
+						 "adi,idle-state", i + 1,
+						 &idle_state);
+		if (ret < 0)
+			return ret;
+		if (idle_state >= ADG792A_DISABLE_STATE) {
+			dev_err(dev, "invalid idle-state %u for mux %u\n",
+				idle_state, index);
+			return -EINVAL;
+		}
+		mux_chip->mux[index].idle_state = idle_state;
+	}
+
+	count = of_property_count_u32_elems(dev->of_node,
+					    "adi,idle-high-impedance");
+	for (i = 0; i < count; ++i) {
+		u32 index;
+
+		ret = of_property_read_u32_index(dev->of_node,
+						 "adi,idle-high-impedance", i,
+						 &index);
+		if (ret < 0)
+			return ret;
+		if (index >= mux_chip->controllers) {
+			dev_err(dev, "invalid mux %u\n", index);
+			return -EINVAL;
+		}
+
+		mux_chip->mux[index].idle_state = ADG792A_DISABLE_STATE;
+	}
+
+	ret = devm_mux_chip_register(dev, mux_chip);
+	if (ret < 0)
+		return ret;
+
+	if (parallel)
+		dev_info(dev, "triple pole quadruple throw mux registered\n");
+	else
+		dev_info(dev, "3x single pole quadruple throw muxes registered\n");
+
+	return 0;
+}
+
+static const struct i2c_device_id adg792a_id[] = {
+	{ .name = "adg792a", },
+	{ .name = "adg792g", },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, adg792a_id);
+
+static const struct of_device_id adg792a_of_match[] = {
+	{ .compatible = "adi,adg792a", },
+	{ .compatible = "adi,adg792g", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, adg792a_of_match);
+
+static struct i2c_driver adg792a_driver = {
+	.driver		= {
+		.name		= "adg792a",
+		.of_match_table = of_match_ptr(adg792a_of_match),
+	},
+	.probe		= adg792a_probe,
+	.id_table	= adg792a_id,
+};
+module_i2c_driver(adg792a_driver);
+
+MODULE_DESCRIPTION("Analog Devices ADG792A/G Triple 4:1 mux driver");
+MODULE_AUTHOR("Peter Rosin <peda@axentia.se");
+MODULE_LICENSE("GPL v2");
-- 
2.1.4