[PATCH v6 6/6] usb: typec: mux: add typec switch simple driver

[Li Jun <jun.li@nxp.com>]

This patch adds a simple typec switch driver for cases which only
needs some simple operations but a dedicated driver is required,
current driver only supports GPIO toggle to switch the super speed
active channel according to typec orientation.

Signed-off-by: Li Jun <jun.li@nxp.com>
---
Changes for v6:
- Use general mux control for typec switch, currently only support
  max 2 GPIOs to control one typec switch with 3 states: orientation
  normal(cc1), reverse(cc2), none(deselected both channels).

Changes for v5:
- A few changes address Andy's comment, remove gpio check as it's
  optional, add module name for Kconfig, use correct header files,
  and other minor changes.
- Remove the mutex lock as it's not required currently.

Changes for v4:
- Change driver name to be switch simple from switch GPIO, to make it
  generic for possible extention.
- Use compatiable "typec-orientation-switch" instead of bool property
  for switch matching.
- Make acitve channel selection GPIO to be optional.
- Remove Andy's R-b tag since the driver changes a lot.

Change for v3:
- Remove file name in driver description.
- Add Andy Shevchenko's Reviewed-by tag.

Changes for v2:
- Use the correct head files for gpio api and of_device_id:
  #include <linux/gpio/consumer.h>
  #include <linux/mod_devicetable.h>
- Add driver dependency on GPIOLIB

 drivers/usb/typec/mux/Kconfig         |  10 +++
 drivers/usb/typec/mux/Makefile        |   1 +
 drivers/usb/typec/mux/switch-simple.c | 126 ++++++++++++++++++++++++++++++++++
 3 files changed, 137 insertions(+)

diff --git a/drivers/usb/typec/mux/Kconfig b/drivers/usb/typec/mux/Kconfig
index a4dbd11..11320d7 100644
--- a/drivers/usb/typec/mux/Kconfig
+++ b/drivers/usb/typec/mux/Kconfig
@@ -18,4 +18,14 @@ config TYPEC_MUX_INTEL_PMC
 	  control the USB role switch and also the multiplexer/demultiplexer
 	  switches used with USB Type-C Alternate Modes.
 
+config TYPEC_SWITCH_SIMPLE
+	tristate "Type-C orientation switch simple driver"
+	depends on GPIOLIB
+	help
+	  Say Y or M if your system need a simple driver for typec switch
+	  control, like use GPIO to select active channel.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called switch-simple.
+
 endmenu
diff --git a/drivers/usb/typec/mux/Makefile b/drivers/usb/typec/mux/Makefile
index 280a6f5..712d0ad 100644
--- a/drivers/usb/typec/mux/Makefile
+++ b/drivers/usb/typec/mux/Makefile
@@ -2,3 +2,4 @@
 
 obj-$(CONFIG_TYPEC_MUX_PI3USB30532)	+= pi3usb30532.o
 obj-$(CONFIG_TYPEC_MUX_INTEL_PMC)	+= intel_pmc_mux.o
+obj-$(CONFIG_TYPEC_SWITCH_SIMPLE)	+= switch-simple.o
diff --git a/drivers/usb/typec/mux/switch-simple.c b/drivers/usb/typec/mux/switch-simple.c
new file mode 100644
index 0000000..4671169
--- /dev/null
+++ b/drivers/usb/typec/mux/switch-simple.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Type-C switch simple control driver
+ *
+ * Copyright 2020 NXP
+ * Author: Jun Li <jun.li@nxp.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/mutex.h>
+#include <linux/mux/driver.h>
+#include <linux/platform_device.h>
+#include <linux/usb/typec_mux.h>
+
+struct typec_switch_simple {
+	struct typec_switch *sw;
+	struct mux_control *mux;
+	struct gpio_descs *switch_gpios;
+};
+
+static int typec_switch_simple_mux_set(struct mux_control *mux, int state)
+{
+	struct typec_switch_simple *typec_ss = mux_chip_priv(mux->chip);
+	DECLARE_BITMAP(values, BITS_PER_TYPE(state));
+
+	values[0] = state;
+	gpiod_set_array_value_cansleep(typec_ss->switch_gpios->ndescs,
+				       typec_ss->switch_gpios->desc,
+				       typec_ss->switch_gpios->info,
+				       values);
+
+	return 0;
+}
+
+static const struct mux_control_ops typec_switch_mux_ops = {
+	.set = typec_switch_simple_mux_set,
+};
+
+static int typec_switch_simple_probe(struct platform_device *pdev)
+{
+	struct device			*dev = &pdev->dev;
+	struct mux_chip			*mux_chip;
+	struct typec_switch_desc	sw_desc;
+	struct typec_switch_simple	*typec_ss;
+	int				idle_state;
+	int				pins;
+	int				ret;
+
+	pins = gpiod_count(dev, "switch");
+	mux_chip = devm_mux_chip_alloc(dev, 1, sizeof(*typec_ss));
+	if (IS_ERR(mux_chip))
+		return PTR_ERR(mux_chip);
+
+	typec_ss = mux_chip_priv(mux_chip);
+	mux_chip->ops = &typec_switch_mux_ops;
+
+	/* Get the super speed active channel selection GPIO */
+	typec_ss->switch_gpios = devm_gpiod_get_array_optional(dev,
+				 "switch", GPIOD_OUT_LOW);
+	if (IS_ERR(typec_ss->switch_gpios))
+		return PTR_ERR(typec_ss->switch_gpios);
+
+	if (pins) {
+		WARN_ON(pins != typec_ss->switch_gpios->ndescs || pins > 2);
+		mux_chip->mux->states = pins + 1;
+	}
+
+	ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state);
+	if (ret >= 0 && idle_state != MUX_IDLE_AS_IS) {
+		if (idle_state < 0 || idle_state >= mux_chip->mux->states) {
+			dev_err(dev, "invalid idle-state %u\n", idle_state);
+			return -EINVAL;
+		}
+		mux_chip->mux->idle_state = idle_state;
+	}
+
+	ret = devm_mux_chip_register(dev, mux_chip);
+	if (ret < 0)
+		return ret;
+
+	platform_set_drvdata(pdev, typec_ss);
+	sw_desc.drvdata = typec_ss;
+	sw_desc.fwnode = dev->fwnode;
+
+	typec_ss->sw = typec_switch_register(&mux_chip->dev, &sw_desc);
+	if (IS_ERR(typec_ss->sw)) {
+		dev_err(dev, "Error registering typec switch: %ld\n",
+			PTR_ERR(typec_ss->sw));
+		return PTR_ERR(typec_ss->sw);
+	}
+
+	return 0;
+}
+
+static int typec_switch_simple_remove(struct platform_device *pdev)
+{
+	struct typec_switch_simple *typec_ss = platform_get_drvdata(pdev);
+
+	typec_switch_unregister(typec_ss->sw);
+
+	return 0;
+}
+
+static const struct of_device_id of_typec_switch_simple_match[] = {
+	{ .compatible = "typec-orientation-switch" },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, of_typec_switch_simple_match);
+
+static struct platform_driver typec_switch_simple_driver = {
+	.probe		= typec_switch_simple_probe,
+	.remove		= typec_switch_simple_remove,
+	.driver		= {
+		.name	= "typec-switch-simple",
+		.of_match_table = of_typec_switch_simple_match,
+	},
+};
+
+module_platform_driver(typec_switch_simple_driver);
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("TypeC Orientation Switch Simple driver");
+MODULE_AUTHOR("Jun Li <jun.li@nxp.com>");
-- 
2.7.4