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

Signed-off-by: Peter Rosin <p...@axentia.se>
---
 drivers/misc/Kconfig       |  12 ++++
 drivers/misc/Makefile      |   1 +
 drivers/misc/mux-adg792a.c | 154 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 167 insertions(+)
 create mode 100644 drivers/misc/mux-adg792a.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 2ce675e410c5..45567a444bbf 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -780,6 +780,18 @@ 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
+         parellel 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/misc/Makefile b/drivers/misc/Makefile
index 0befa2bba762..10ab8d34c9e5 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o
 obj-$(CONFIG_CXL_BASE)         += cxl/
 obj-$(CONFIG_PANEL)             += panel.o
 obj-$(CONFIG_MULTIPLEXER)              += mux-core.o
+obj-$(CONFIG_MUX_ADG792A)      += mux-adg792a.o
 obj-$(CONFIG_MUX_GPIO)         += mux-gpio.o
 
 lkdtm-$(CONFIG_LKDTM)          += lkdtm_core.o
diff --git a/drivers/misc/mux-adg792a.c b/drivers/misc/mux-adg792a.c
new file mode 100644
index 000000000000..7d309a78af65
--- /dev/null
+++ b/drivers/misc/mux-adg792a.c
@@ -0,0 +1,154 @@
+/*
+ * Multiplexer driver for Analog Devices ADG792A/G Triple 4:1 mux
+ *
+ * Copyright (C) 2016 Axentia Technologies AB
+ *
+ * Author: Peter Rosin <p...@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)
+#define ADG792A_KEEP_STATE     (5)
+
+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 ret;
+       int i;
+
+       parallel = of_property_read_bool(i2c->dev.of_node, "adi,parallel");
+
+       mux_chip = mux_chip_alloc(dev, parallel ? 1 : 3, 0);
+       if (!mux_chip)
+               return -ENOMEM;
+
+       mux_chip->ops = &adg792a_ops;
+       dev_set_drvdata(dev, mux_chip);
+
+       ret = i2c_smbus_write_byte_data(i2c, ADG792A_DISABLE_ALL,
+                                       ADG792A_RESET | ADG792A_LDSW);
+       if (ret < 0)
+               goto free_mux_chip;
+
+       for (i = 0; i < mux_chip->controllers; ++i) {
+               struct mux_control *mux = &mux_chip->mux[i];
+               u32 idle_state;
+
+               mux->states = 4;
+
+               ret = of_property_read_u32_index(i2c->dev.of_node,
+                                                "adi,idle-state", i,
+                                                &idle_state);
+               if (ret >= 0) {
+                       if (idle_state > ADG792A_KEEP_STATE) {
+                               dev_err(dev, "invalid idle-state %u\n",
+                                       idle_state);
+                               ret = -EINVAL;
+                               goto free_mux_chip;
+                       }
+                       if (idle_state != ADG792A_KEEP_STATE)
+                               mux->idle_state = idle_state;
+               }
+       }
+
+       ret = mux_chip_register(mux_chip);
+       if (ret < 0) {
+               dev_err(dev, "failed to register mux-chip\n");
+               goto free_mux_chip;
+       }
+
+       if (parallel)
+               dev_info(dev, "1 triple 4-way mux-controller registered\n");
+       else
+               dev_info(dev, "3 4-way mux-controllers registered\n");
+
+       return 0;
+
+free_mux_chip:
+       mux_chip_free(mux_chip);
+       return ret;
+}
+
+static int adg792a_remove(struct i2c_client *i2c)
+{
+       struct mux_chip *mux_chip = dev_get_drvdata(&i2c->dev);
+
+       mux_chip_unregister(mux_chip);
+       mux_chip_free(mux_chip);
+
+       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,
+       .remove         = adg792a_remove,
+       .id_table       = adg792a_id,
+};
+module_i2c_driver(adg792a_driver);
+
+MODULE_DESCRIPTION("Analog Devices ADG792A/G Triple 4:1 mux driver");
+MODULE_AUTHOR("Peter Rosin <p...@axentia.se");
+MODULE_LICENSE("GPL v2");
-- 
2.1.4

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