[PATCH 07/11] extcon: intel-int3496: Add support for controlling the USB-role mux

Hans de Goede
2017-09-01T21:49:23Z

Cherry Trail SoCs have a built-in USB-role mux for switching between
the host and device controllers, rather then using an external mux
controller by a GPIO.

There is a driver using the mux-subsys to control this mux, this
commit adds support to the intel-int3496 driver to get a mux_controller
handle for the mux and set the mux through the mux-subsys rather then
through a GPIO.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
drivers/extcon/Kconfig | 1 +
drivers/extcon/extcon-intel-int3496.c | 59 ++++++++++++++++++++++++++++++++++-
2 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
index a7bca4207f44..7ab6acc9708a 100644
--- a/drivers/extcon/Kconfig
+++ b/drivers/extcon/Kconfig
@@ -45,6 +45,7 @@ config EXTCON_GPIO
config EXTCON_INTEL_INT3496
tristate "Intel INT3496 ACPI device extcon driver"
depends on GPIOLIB && ACPI && (X86 || COMPILE_TEST)
+ select MULTIPLEXER
help
Say Y here to enable extcon support for USB OTG ports controlled by
an Intel INT3496 ACPI device.
diff --git a/drivers/extcon/extcon-intel-int3496.c b/drivers/extcon/extcon-intel-int3496.c
index 1a45e745717d..cea9c9b1521c 100644
--- a/drivers/extcon/extcon-intel-int3496.c
+++ b/drivers/extcon/extcon-intel-int3496.c
@@ -23,8 +23,12 @@
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/module.h>
+#include <linux/mux/consumer.h>
#include <linux/platform_device.h>

+#include <asm/cpu_device_id.h>
+#include <asm/intel-family.h>
+
#define INT3496_GPIO_USB_ID 0
#define INT3496_GPIO_VBUS_EN 1
#define INT3496_GPIO_USB_MUX 2
@@ -37,6 +41,8 @@ struct int3496_data {
struct gpio_desc *gpio_usb_id;
struct gpio_desc *gpio_vbus_en;
struct gpio_desc *gpio_usb_mux;
+ struct mux_control *usb_mux;
+ bool usb_mux_set;
int usb_id_irq;
};

@@ -56,11 +62,31 @@ static const struct acpi_gpio_mapping acpi_int3496_default_gpios[] = {
{ },
};

+static struct mux_lookup acpi_int3496_cht_mux_lookup[] = {
+ {
+ .provider = "intel_cht_usb_mux",
+ .dev_id = "INT3496:00",
+ .mux_name = "usb-role-mux",
+ },
+};
+
+#define ICPU(model) { X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, }
+
+static const struct x86_cpu_id cht_cpu_ids[] = {
+ ICPU(INTEL_FAM6_ATOM_AIRMONT), /* Braswell, Cherry Trail */
+ {}
+};
+
+static bool int3496_soc_has_mux(void)
+{
+ return x86_match_cpu(cht_cpu_ids);
+}
+
static void int3496_do_usb_id(struct work_struct *work)
{
struct int3496_data *data =
container_of(work, struct int3496_data, work.work);
- int id = gpiod_get_value_cansleep(data->gpio_usb_id);
+ int ret, id = gpiod_get_value_cansleep(data->gpio_usb_id);

/* id == 1: PERIPHERAL, id == 0: HOST */
dev_dbg(data->dev, "Connected %s cable\n", id ? "PERIPHERAL" : "HOST");
@@ -72,6 +98,22 @@ static void int3496_do_usb_id(struct work_struct *work)
if (!IS_ERR(data->gpio_usb_mux))
gpiod_direction_output(data->gpio_usb_mux, id);

+ if (data->usb_mux) {
+ /*
+ * The mux framework expects multiple competing users, we must
+ * release our previous setting before applying the new one.
+ */
+ if (data->usb_mux_set)
+ mux_control_deselect(data->usb_mux);
+
+ ret = mux_control_select(data->usb_mux,
+ id ? MUX_USB_DEVICE : MUX_USB_HOST);
+ if (ret)
+ dev_err(data->dev, "Error setting mux: %d\n", ret);
+
+ data->usb_mux_set = ret == 0;
+ }
+
if (!IS_ERR(data->gpio_vbus_en))
gpiod_direction_output(data->gpio_vbus_en, !id);

@@ -107,6 +149,21 @@ static int int3496_probe(struct platform_device *pdev)
data->dev = dev;
INIT_DELAYED_WORK(&data->work, int3496_do_usb_id);

+ if (int3496_soc_has_mux()) {
+ mux_add_table(acpi_int3496_cht_mux_lookup,
+ ARRAY_SIZE(acpi_int3496_cht_mux_lookup));
+ data->usb_mux = devm_mux_control_get(dev, "usb-role-mux");
+ /* Doing this here keeps our error handling clean. */
+ mux_remove_table(acpi_int3496_cht_mux_lookup,
+ ARRAY_SIZE(acpi_int3496_cht_mux_lookup));
+ if (IS_ERR(data->usb_mux)) {
+ ret = PTR_ERR(data->usb_mux);
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "can't get mux: %d\n", ret);
+ return ret;
+ }
+ }
+
data->gpio_usb_id = devm_gpiod_get(dev, "id", GPIOD_IN);
if (IS_ERR(data->gpio_usb_id)) {
ret = PTR_ERR(data->gpio_usb_id);
--
2.13.5