Input: goodix - add support for getting IRQ + reset GPIOs on Cherry Trail devices

On most Cherry Trail (x86, UEFI + ACPI) devices the ACPI tables do not have
a _DSD with a "daffd814-6eba-4d8c-8a91-bc9bbf4aa301" UUID, adding
"irq-gpios" and "reset-gpios" mappings, so we cannot get the GPIOS by name
without first manually adding mappings ourselves.

These devices contain 1 GpioInt and 1 GpioIo resource in their _CRS table:

Method (_CRS, 0, NotSerialized)  // _CRS: Current Resource Settings
{
    Name (RBUF, ResourceTemplate ()
    {
        I2cSerialBusV2 (0x0014, ControllerInitiated, 0x00061A80,
            AddressingMode7Bit, "\\_SB.PCI0.I2C2",
            0x00, ResourceConsumer, , Exclusive,
            )
        GpioInt (Edge, ActiveLow, Shared, PullDefault, 0x0000,
            "\\_SB.GPO1", 0x00, ResourceConsumer, ,
            )
            {   // Pin list
                0x0013
            }
        GpioIo (Shared, PullDefault, 0x0000, 0x0000,
            IoRestrictionOutputOnly,
            "\\_SB.GPO1", 0x00, ResourceConsumer, ,
            )
            {   // Pin list
                0x0019
            }
    })
    Return (RBUF) /* \_SB_.PCI0.I2C2.TCS1._CRS.RBUF */
}

There is no fixed order for these 2. This commit adds code to check that
there is 1 of each as expected and then registers a mapping matching their
order using devm_acpi_dev_add_driver_gpios().

This gives us access to both GPIOs allowing us to properly suspend the
controller during suspend, and making it possible to reset the controller
if necessary.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1786317
BugLink: https://github.com/nexus511/gpd-ubuntu-packages/issues/10
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=199207
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Bastien Nocera <hadess@hadess.net>
Link: https://lore.kernel.org/r/20200307121505.3707-4-hdegoede@redhat.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
index 70212ea..f7af540 100644 (file)
--- a/drivers/input/touchscreen/goodix.c
+++ b/drivers/input/touchscreen/goodix.c
@@ -34,6 +34,7 @@ struct goodix_ts_data;
 enum goodix_irq_pin_access_method {
        IRQ_PIN_ACCESS_NONE,
        IRQ_PIN_ACCESS_GPIO,
+       IRQ_PIN_ACCESS_ACPI_GPIO,
 };
 
 struct goodix_chip_data {
@@ -53,6 +54,8 @@ struct goodix_ts_data {
        struct regulator *vddio;
        struct gpio_desc *gpiod_int;
        struct gpio_desc *gpiod_rst;
+       int gpio_count;
+       int gpio_int_idx;
        u16 id;
        u16 version;
        const char *cfg_name;
@@ -537,6 +540,12 @@ static int goodix_irq_direction_output(struct goodix_ts_data *ts,
                return -EINVAL;
        case IRQ_PIN_ACCESS_GPIO:
                return gpiod_direction_output(ts->gpiod_int, value);
+       case IRQ_PIN_ACCESS_ACPI_GPIO:
+               /*
+                * The IRQ pin triggers on a falling edge, so its gets marked
+                * as active-low, use output_raw to avoid the value inversion.
+                */
+               return gpiod_direction_output_raw(ts->gpiod_int, value);
        }
 
        return -EINVAL; /* Never reached */
@@ -551,6 +560,7 @@ static int goodix_irq_direction_input(struct goodix_ts_data *ts)
                        __func__);
                return -EINVAL;
        case IRQ_PIN_ACCESS_GPIO:
+       case IRQ_PIN_ACCESS_ACPI_GPIO:
                return gpiod_direction_input(ts->gpiod_int);
        }
 
@@ -615,6 +625,94 @@ static int goodix_reset(struct goodix_ts_data *ts)
        return 0;
 }
 
+#if defined CONFIG_X86 && defined CONFIG_ACPI
+static const struct acpi_gpio_params first_gpio = { 0, 0, false };
+static const struct acpi_gpio_params second_gpio = { 1, 0, false };
+
+static const struct acpi_gpio_mapping acpi_goodix_int_first_gpios[] = {
+       { GOODIX_GPIO_INT_NAME "-gpios", &first_gpio, 1 },
+       { GOODIX_GPIO_RST_NAME "-gpios", &second_gpio, 1 },
+       { },
+};
+
+static const struct acpi_gpio_mapping acpi_goodix_int_last_gpios[] = {
+       { GOODIX_GPIO_RST_NAME "-gpios", &first_gpio, 1 },
+       { GOODIX_GPIO_INT_NAME "-gpios", &second_gpio, 1 },
+       { },
+};
+
+static int goodix_resource(struct acpi_resource *ares, void *data)
+{
+       struct goodix_ts_data *ts = data;
+       struct device *dev = &ts->client->dev;
+       struct acpi_resource_gpio *gpio;
+
+       switch (ares->type) {
+       case ACPI_RESOURCE_TYPE_GPIO:
+               gpio = &ares->data.gpio;
+               if (gpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT) {
+                       if (ts->gpio_int_idx == -1) {
+                               ts->gpio_int_idx = ts->gpio_count;
+                       } else {
+                               dev_err(dev, "More then one GpioInt resource, ignoring ACPI GPIO resources\n");
+                               ts->gpio_int_idx = -2;
+                       }
+               }
+               ts->gpio_count++;
+               break;
+       default:
+               break;
+       }
+
+       return 0;
+}
+
+/*
+ * This function gets called in case we fail to get the irq GPIO directly
+ * because the ACPI tables lack GPIO-name to APCI _CRS index mappings
+ * (no _DSD UUID daffd814-6eba-4d8c-8a91-bc9bbf4aa301 data).
+ * In that case we add our own mapping and then goodix_get_gpio_config()
+ * retries to get the GPIOs based on the added mapping.
+ */
+static int goodix_add_acpi_gpio_mappings(struct goodix_ts_data *ts)
+{
+       const struct acpi_gpio_mapping *gpio_mapping = NULL;
+       struct device *dev = &ts->client->dev;
+       LIST_HEAD(resources);
+       int ret;
+
+       ts->gpio_count = 0;
+       ts->gpio_int_idx = -1;
+       ret = acpi_dev_get_resources(ACPI_COMPANION(dev), &resources,
+                                    goodix_resource, ts);
+       if (ret < 0) {
+               dev_err(dev, "Error getting ACPI resources: %d\n", ret);
+               return ret;
+       }
+
+       acpi_dev_free_resource_list(&resources);
+
+       if (ts->gpio_count == 2 && ts->gpio_int_idx == 0) {
+               ts->irq_pin_access_method = IRQ_PIN_ACCESS_ACPI_GPIO;
+               gpio_mapping = acpi_goodix_int_first_gpios;
+       } else if (ts->gpio_count == 2 && ts->gpio_int_idx == 1) {
+               ts->irq_pin_access_method = IRQ_PIN_ACCESS_ACPI_GPIO;
+               gpio_mapping = acpi_goodix_int_last_gpios;
+       } else {
+               dev_warn(dev, "Unexpected ACPI resources: gpio_count %d, gpio_int_idx %d\n",
+                        ts->gpio_count, ts->gpio_int_idx);
+               return -EINVAL;
+       }
+
+       return devm_acpi_dev_add_driver_gpios(dev, gpio_mapping);
+}
+#else
+static int goodix_add_acpi_gpio_mappings(struct goodix_ts_data *ts)
+{
+       return -EINVAL;
+}
+#endif /* CONFIG_X86 && CONFIG_ACPI */
+
 /**
  * goodix_get_gpio_config - Get GPIO config from ACPI/DT
  *
@@ -625,6 +723,7 @@ static int goodix_get_gpio_config(struct goodix_ts_data *ts)
        int error;
        struct device *dev;
        struct gpio_desc *gpiod;
+       bool added_acpi_mappings = false;
 
        if (!ts->client)
                return -EINVAL;
@@ -648,6 +747,7 @@ static int goodix_get_gpio_config(struct goodix_ts_data *ts)
                return error;
        }
 
+retry_get_irq_gpio:
        /* Get the interrupt GPIO pin number */
        gpiod = devm_gpiod_get_optional(dev, GOODIX_GPIO_INT_NAME, GPIOD_IN);
        if (IS_ERR(gpiod)) {
@@ -657,6 +757,11 @@ static int goodix_get_gpio_config(struct goodix_ts_data *ts)
                                GOODIX_GPIO_INT_NAME, error);
                return error;
        }
+       if (!gpiod && has_acpi_companion(dev) && !added_acpi_mappings) {
+               added_acpi_mappings = true;
+               if (goodix_add_acpi_gpio_mappings(ts) == 0)
+                       goto retry_get_irq_gpio;
+       }
 
        ts->gpiod_int = gpiod;
 
@@ -672,10 +777,25 @@ static int goodix_get_gpio_config(struct goodix_ts_data *ts)
 
        ts->gpiod_rst = gpiod;
 
-       if (ts->gpiod_int && ts->gpiod_rst) {
-               ts->reset_controller_at_probe = true;
-               ts->load_cfg_from_disk = true;
-               ts->irq_pin_access_method = IRQ_PIN_ACCESS_GPIO;
+       switch (ts->irq_pin_access_method) {
+       case IRQ_PIN_ACCESS_ACPI_GPIO:
+               /*
+                * We end up here if goodix_add_acpi_gpio_mappings() has
+                * called devm_acpi_dev_add_driver_gpios() because the ACPI
+                * tables did not contain name to index mappings.
+                * Check that we successfully got both GPIOs after we've
+                * added our own acpi_gpio_mapping and if we did not get both
+                * GPIOs reset irq_pin_access_method to IRQ_PIN_ACCESS_NONE.
+                */
+               if (!ts->gpiod_int || !ts->gpiod_rst)
+                       ts->irq_pin_access_method = IRQ_PIN_ACCESS_NONE;
+               break;
+       default:
+               if (ts->gpiod_int && ts->gpiod_rst) {
+                       ts->reset_controller_at_probe = true;
+                       ts->load_cfg_from_disk = true;
+                       ts->irq_pin_access_method = IRQ_PIN_ACCESS_GPIO;
+               }
        }
 
        return 0;