usb: typec: mux: Introduce GPIO-based SBU mux

A design found in various Qualcomm-based boards is to use a USB switch,
controlled through a pair of GPIO lines to connect, disconnect and
switch the orientation of the SBU lines in USB Type-C applications.

This introduces a generic driver, which implements the typec_switch and
typec_mux interfaces to perform these operations.

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Link: https://lore.kernel.org/r/20230113041115.4189210-2-quic_bjorande@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/mux/Kconfig b/drivers/usb/typec/mux/Kconfig
index 5eb2c17..c46fa4f 100644 (file)
--- a/drivers/usb/typec/mux/Kconfig
+++ b/drivers/usb/typec/mux/Kconfig
@@ -12,6 +12,12 @@ config TYPEC_MUX_FSA4480
          common USB Type-C connector.
          If compiled as a module, the module will be named fsa4480.
 
+config TYPEC_MUX_GPIO_SBU
+       tristate "Generic GPIO based SBU mux for USB Type-C applications"
+       help
+         Say Y or M if your system uses a GPIO based mux for managing the
+         connected state and the swapping of the SBU lines in a Type-C port.
+
 config TYPEC_MUX_PI3USB30532
        tristate "Pericom PI3USB30532 Type-C cross switch driver"
        depends on I2C

diff --git a/drivers/usb/typec/mux/Makefile b/drivers/usb/typec/mux/Makefile
index e52a56c..dda67e1 100644 (file)
--- a/drivers/usb/typec/mux/Makefile
+++ b/drivers/usb/typec/mux/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_TYPEC_MUX_FSA4480)                += fsa4480.o
+obj-$(CONFIG_TYPEC_MUX_GPIO_SBU)       += gpio-sbu-mux.o
 obj-$(CONFIG_TYPEC_MUX_PI3USB30532)    += pi3usb30532.o
 obj-$(CONFIG_TYPEC_MUX_INTEL_PMC)      += intel_pmc_mux.o

diff --git a/drivers/usb/typec/mux/gpio-sbu-mux.c b/drivers/usb/typec/mux/gpio-sbu-mux.c
new file mode 100644 (file)
index 0000000..f62516d
--- /dev/null
+++ b/drivers/usb/typec/mux/gpio-sbu-mux.c
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022 Linaro Ltd.
+ */
+
+#include <linux/bits.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/gpio/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/usb/typec_dp.h>
+#include <linux/usb/typec_mux.h>
+
+struct gpio_sbu_mux {
+       struct gpio_desc *enable_gpio;
+       struct gpio_desc *select_gpio;
+
+       struct typec_switch_dev *sw;
+       struct typec_mux_dev *mux;
+
+       struct mutex lock; /* protect enabled and swapped */
+       bool enabled;
+       bool swapped;
+};
+
+static int gpio_sbu_switch_set(struct typec_switch_dev *sw,
+                              enum typec_orientation orientation)
+{
+       struct gpio_sbu_mux *sbu_mux = typec_switch_get_drvdata(sw);
+       bool enabled;
+       bool swapped;
+
+       mutex_lock(&sbu_mux->lock);
+
+       enabled = sbu_mux->enabled;
+       swapped = sbu_mux->swapped;
+
+       switch (orientation) {
+       case TYPEC_ORIENTATION_NONE:
+               enabled = false;
+               break;
+       case TYPEC_ORIENTATION_NORMAL:
+               swapped = false;
+               break;
+       case TYPEC_ORIENTATION_REVERSE:
+               swapped = true;
+               break;
+       }
+
+       if (enabled != sbu_mux->enabled)
+               gpiod_set_value(sbu_mux->enable_gpio, enabled);
+
+       if (swapped != sbu_mux->swapped)
+               gpiod_set_value(sbu_mux->select_gpio, swapped);
+
+       sbu_mux->enabled = enabled;
+       sbu_mux->swapped = swapped;
+
+       mutex_unlock(&sbu_mux->lock);
+
+       return 0;
+}
+
+static int gpio_sbu_mux_set(struct typec_mux_dev *mux,
+                           struct typec_mux_state *state)
+{
+       struct gpio_sbu_mux *sbu_mux = typec_mux_get_drvdata(mux);
+
+       mutex_lock(&sbu_mux->lock);
+
+       switch (state->mode) {
+       case TYPEC_STATE_SAFE:
+       case TYPEC_STATE_USB:
+               sbu_mux->enabled = false;
+               break;
+       case TYPEC_DP_STATE_C:
+       case TYPEC_DP_STATE_D:
+       case TYPEC_DP_STATE_E:
+               sbu_mux->enabled = true;
+               break;
+       default:
+               break;
+       }
+
+       gpiod_set_value(sbu_mux->enable_gpio, sbu_mux->enabled);
+
+       mutex_unlock(&sbu_mux->lock);
+
+       return 0;
+}
+
+static int gpio_sbu_mux_probe(struct platform_device *pdev)
+{
+       struct typec_switch_desc sw_desc = { };
+       struct typec_mux_desc mux_desc = { };
+       struct device *dev = &pdev->dev;
+       struct gpio_sbu_mux *sbu_mux;
+
+       sbu_mux = devm_kzalloc(dev, sizeof(*sbu_mux), GFP_KERNEL);
+       if (!sbu_mux)
+               return -ENOMEM;
+
+       mutex_init(&sbu_mux->lock);
+
+       sbu_mux->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
+       if (IS_ERR(sbu_mux->enable_gpio))
+               return dev_err_probe(dev, PTR_ERR(sbu_mux->enable_gpio),
+                                    "unable to acquire enable gpio\n");
+
+       sbu_mux->select_gpio = devm_gpiod_get(dev, "select", GPIOD_OUT_LOW);
+       if (IS_ERR(sbu_mux->select_gpio))
+               return dev_err_probe(dev, PTR_ERR(sbu_mux->select_gpio),
+                                    "unable to acquire select gpio\n");
+
+       sw_desc.drvdata = sbu_mux;
+       sw_desc.fwnode = dev_fwnode(dev);
+       sw_desc.set = gpio_sbu_switch_set;
+
+       sbu_mux->sw = typec_switch_register(dev, &sw_desc);
+       if (IS_ERR(sbu_mux->sw))
+               return dev_err_probe(dev, PTR_ERR(sbu_mux->sw),
+                                    "failed to register typec switch\n");
+
+       mux_desc.drvdata = sbu_mux;
+       mux_desc.fwnode = dev_fwnode(dev);
+       mux_desc.set = gpio_sbu_mux_set;
+
+       sbu_mux->mux = typec_mux_register(dev, &mux_desc);
+       if (IS_ERR(sbu_mux->mux)) {
+               typec_switch_unregister(sbu_mux->sw);
+               return dev_err_probe(dev, PTR_ERR(sbu_mux->mux),
+                                    "failed to register typec mux\n");
+       }
+
+       platform_set_drvdata(pdev, sbu_mux);
+
+       return 0;
+}
+
+static int gpio_sbu_mux_remove(struct platform_device *pdev)
+{
+       struct gpio_sbu_mux *sbu_mux = platform_get_drvdata(pdev);
+
+       gpiod_set_value(sbu_mux->enable_gpio, 0);
+
+       typec_mux_unregister(sbu_mux->mux);
+       typec_switch_unregister(sbu_mux->sw);
+
+       return 0;
+}
+
+static const struct of_device_id gpio_sbu_mux_match[] = {
+       { .compatible = "gpio-sbu-mux", },
+       {}
+};
+MODULE_DEVICE_TABLE(of, gpio_sbu_mux_match);
+
+static struct platform_driver gpio_sbu_mux_driver = {
+       .probe = gpio_sbu_mux_probe,
+       .remove = gpio_sbu_mux_remove,
+       .driver = {
+               .name = "gpio_sbu_mux",
+               .of_match_table = gpio_sbu_mux_match,
+       },
+};
+module_platform_driver(gpio_sbu_mux_driver);
+
+MODULE_DESCRIPTION("GPIO based SBU mux driver");
+MODULE_LICENSE("GPL");