mfd: arizona: Add support for ACPI enumeration of WM5102 connected over SPI

The Intel Bay Trail (x86/ACPI) based Lenovo Yoga Tablet 2 series use
a WM5102 codec connected over SPI.

Add support for ACPI enumeration to arizona-spi so that arizona-spi can
bind to the codec on these tablets.

This is loosely based on an earlier attempt (for Android-x86) at this by
Christian Hartmann, combined with insights in things like the speaker GPIO
from the android-x86 android port for the Lenovo Yoga Tablet 2 1051F/L [1].

[1] https://github.com/Kitsune2222/Android_Yoga_Tablet_2-1051F_Kernel

Cc: Christian Hartmann <cornogle@googlemail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/arizona-spi.c

@@ -7,7 +7,10 @@
  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  */
 
+#include <linux/acpi.h>
 #include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/machine.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
@@ -15,11 +18,128 @@
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
 #include <linux/of.h>
+#include <uapi/linux/input-event-codes.h>
 
 #include <linux/mfd/arizona/core.h>
 
 #include "arizona.h"
 
+#ifdef CONFIG_ACPI
+const struct acpi_gpio_params reset_gpios = { 1, 0, false };
+const struct acpi_gpio_params ldoena_gpios = { 2, 0, false };
+
+static const struct acpi_gpio_mapping arizona_acpi_gpios[] = {
+	{ "reset-gpios", &reset_gpios, 1, },
+	{ "wlf,ldoena-gpios", &ldoena_gpios, 1 },
+	{ }
+};
+
+/*
+ * The ACPI resources for the device only describe external GPIO-s. They do
+ * not provide mappings for the GPIO-s coming from the Arizona codec itself.
+ */
+static const struct gpiod_lookup arizona_soc_gpios[] = {
+	{ "arizona", 2, "wlf,spkvdd-ena", 0, GPIO_ACTIVE_HIGH },
+	{ "arizona", 4, "wlf,micd-pol", 0, GPIO_ACTIVE_LOW },
+};
+
+/*
+ * The AOSP 3.5 mm Headset: Accessory Specification gives the following values:
+ * Function A Play/Pause:           0 ohm
+ * Function D Voice assistant:    135 ohm
+ * Function B Volume Up           240 ohm
+ * Function C Volume Down         470 ohm
+ * Minimum Mic DC resistance     1000 ohm
+ * Minimum Ear speaker impedance   16 ohm
+ * Note the first max value below must be less then the min. speaker impedance,
+ * to allow CTIA/OMTP detection to work. The other max values are the closest
+ * value from extcon-arizona.c:arizona_micd_levels halfway 2 button resistances.
+ */
+static const struct arizona_micd_range arizona_micd_aosp_ranges[] = {
+	{ .max =  11, .key = KEY_PLAYPAUSE },
+	{ .max = 186, .key = KEY_VOICECOMMAND },
+	{ .max = 348, .key = KEY_VOLUMEUP },
+	{ .max = 752, .key = KEY_VOLUMEDOWN },
+};
+
+static void arizona_spi_acpi_remove_lookup(void *lookup)
+{
+	gpiod_remove_lookup_table(lookup);
+}
+
+static int arizona_spi_acpi_probe(struct arizona *arizona)
+{
+	struct gpiod_lookup_table *lookup;
+	acpi_status status;
+	int ret;
+
+	/* Add mappings for the 2 ACPI declared GPIOs used for reset and ldo-ena */
+	devm_acpi_dev_add_driver_gpios(arizona->dev, arizona_acpi_gpios);
+
+	/* Add lookups for the SoCs own GPIOs used for micdet-polarity and spkVDD-enable */
+	lookup = devm_kzalloc(arizona->dev,
+			      struct_size(lookup, table, ARRAY_SIZE(arizona_soc_gpios) + 1),
+			      GFP_KERNEL);
+	if (!lookup)
+		return -ENOMEM;
+
+	lookup->dev_id = dev_name(arizona->dev);
+	memcpy(lookup->table, arizona_soc_gpios, sizeof(arizona_soc_gpios));
+
+	gpiod_add_lookup_table(lookup);
+	ret = devm_add_action_or_reset(arizona->dev, arizona_spi_acpi_remove_lookup, lookup);
+	if (ret)
+		return ret;
+
+	/* Enable 32KHz clock from SoC to codec for jack-detect */
+	status = acpi_evaluate_object(ACPI_HANDLE(arizona->dev), "CLKE", NULL, NULL);
+	if (ACPI_FAILURE(status))
+		dev_warn(arizona->dev, "Failed to enable 32KHz clk ACPI error %d\n", status);
+
+	/*
+	 * Some DSDTs wrongly declare the IRQ trigger-type as IRQF_TRIGGER_FALLING
+	 * The IRQ line will stay low when a new IRQ event happens between reading
+	 * the IRQ status flags and acknowledging them. When the IRQ line stays
+	 * low like this the IRQ will never trigger again when its type is set
+	 * to IRQF_TRIGGER_FALLING. Correct the IRQ trigger-type to fix this.
+	 *
+	 * Note theoretically it is possible that some boards are not capable
+	 * of handling active low level interrupts. In that case setting the
+	 * flag to IRQF_TRIGGER_FALLING would not be a bug (and we would need
+	 * to work around this) but so far all known usages of IRQF_TRIGGER_FALLING
+	 * are a bug in the board's DSDT.
+	 */
+	arizona->pdata.irq_flags = IRQF_TRIGGER_LOW;
+
+	/* Wait 200 ms after jack insertion */
+	arizona->pdata.micd_detect_debounce = 200;
+
+	/* Use standard AOSP values for headset-button mappings */
+	arizona->pdata.micd_ranges = arizona_micd_aosp_ranges;
+	arizona->pdata.num_micd_ranges = ARRAY_SIZE(arizona_micd_aosp_ranges);
+
+	return 0;
+}
+
+static const struct acpi_device_id arizona_acpi_match[] = {
+	{
+		.id = "WM510204",
+		.driver_data = WM5102,
+	},
+	{
+		.id = "WM510205",
+		.driver_data = WM5102,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, arizona_acpi_match);
+#else
+static int arizona_spi_acpi_probe(struct arizona *arizona)
+{
+	return -ENODEV;
+}
+#endif
+
 static int arizona_spi_probe(struct spi_device *spi)
 {
 	const struct spi_device_id *id = spi_get_device_id(spi);
@@ -77,6 +197,12 @@ static int arizona_spi_probe(struct spi_device *spi)
 	arizona->dev = &spi->dev;
 	arizona->irq = spi->irq;
 
+	if (has_acpi_companion(&spi->dev)) {
+		ret = arizona_spi_acpi_probe(arizona);
+		if (ret)
+			return ret;
+	}
+
 	return arizona_dev_init(arizona);
 }
 
@@ -104,6 +230,7 @@ static struct spi_driver arizona_spi_driver = {
 		.name	= "arizona",
 		.pm	= &arizona_pm_ops,
 		.of_match_table	= of_match_ptr(arizona_of_match),
+		.acpi_match_table = ACPI_PTR(arizona_acpi_match),
 	},
 	.probe		= arizona_spi_probe,
 	.remove		= arizona_spi_remove,