[PATCH 5.4 036/109] gpio: pca953x: Override IRQ for one of the expanders on Galileo Gen 2

[Greg Kroah-Hartman]

From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

[ Upstream commit ba8c90c6184784b397807b72403656085ac2f8c1 ]

ACPI table on Intel Galileo Gen 2 has wrong pin number for IRQ resource
of one of the IÂC GPIO expanders. Since we know what that number is and
luckily have GPIO bases fixed for SoC's controllers, we may use a simple
DMI quirk to match the platform and retrieve GpioInt() pin on it for
the expander in question.

Mika suggested the way to avoid a quirk in the GPIO ACPI library and
here is the second, almost rewritten version of it.

Fixes: f32517bf1ae0 ("gpio: pca953x: support ACPI devices found on Galileo Gen2")
Depends-on: 25e3ef894eef ("gpio: acpi: Split out acpi_gpio_get_irq_resource() helper")
Suggested-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpio/gpio-pca953x.c | 79 +++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index 29ba26742c8f5..c935019c0257c 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -107,6 +107,79 @@ static const struct i2c_device_id pca953x_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, pca953x_id);
 
+#ifdef CONFIG_GPIO_PCA953X_IRQ
+
+#include <linux/dmi.h>
+#include <linux/gpio.h>
+#include <linux/list.h>
+
+static const struct dmi_system_id pca953x_dmi_acpi_irq_info[] = {
+	{
+		/*
+		 * On Intel Galileo Gen 2 board the IRQ pin of one of
+		 * the IÂC GPIO expanders, which has GpioInt() resource,
+		 * is provided as an absolute number instead of being
+		 * relative. Since first controller (gpio-sch.c) and
+		 * second (gpio-dwapb.c) are at the fixed bases, we may
+		 * safely refer to the number in the global space to get
+		 * an IRQ out of it.
+		 */
+		.matches = {
+			DMI_EXACT_MATCH(DMI_BOARD_NAME, "GalileoGen2"),
+		},
+	},
+	{}
+};
+
+#ifdef CONFIG_ACPI
+static int pca953x_acpi_get_pin(struct acpi_resource *ares, void *data)
+{
+	struct acpi_resource_gpio *agpio;
+	int *pin = data;
+
+	if (acpi_gpio_get_irq_resource(ares, &agpio))
+		*pin = agpio->pin_table[0];
+	return 1;
+}
+
+static int pca953x_acpi_find_pin(struct device *dev)
+{
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+	int pin = -ENOENT, ret;
+	LIST_HEAD(r);
+
+	ret = acpi_dev_get_resources(adev, &r, pca953x_acpi_get_pin, &pin);
+	acpi_dev_free_resource_list(&r);
+	if (ret < 0)
+		return ret;
+
+	return pin;
+}
+#else
+static inline int pca953x_acpi_find_pin(struct device *dev) { return -ENXIO; }
+#endif
+
+static int pca953x_acpi_get_irq(struct device *dev)
+{
+	int pin, ret;
+
+	pin = pca953x_acpi_find_pin(dev);
+	if (pin < 0)
+		return pin;
+
+	dev_info(dev, "Applying ACPI interrupt quirk (GPIO %d)\n", pin);
+
+	if (!gpio_is_valid(pin))
+		return -EINVAL;
+
+	ret = gpio_request(pin, "pca953x interrupt");
+	if (ret)
+		return ret;
+
+	return gpio_to_irq(pin);
+}
+#endif
+
 static const struct acpi_device_id pca953x_acpi_ids[] = {
 	{ "INT3491", 16 | PCA953X_TYPE | PCA_LATCH_INT, },
 	{ }
@@ -772,6 +845,12 @@ static int pca953x_irq_setup(struct pca953x_chip *chip,
 	u8 reg_direction[MAX_BANK];
 	int ret, i;
 
+	if (dmi_first_match(pca953x_dmi_acpi_irq_info)) {
+		ret = pca953x_acpi_get_irq(&client->dev);
+		if (ret > 0)
+			client->irq = ret;
+	}
+
 	if (!client->irq)
 		return 0;
 
-- 
2.25.1