of_mmc_spi: add card detect irq support

Signed-off-by: Esben Haabendal <[e-mail]>
Acked-by: Anton Vorontsov <[e-mail]>
Signed-off-by: Grant Likely <[e-mail]>

Documentation/powerpc/dts-bindings/mmc-spi-slot.txt

···
 - voltage-ranges : two cells are required, first cell specifies minimum
   slot voltage (mV), second cell specifies maximum slot voltage (mV).
   Several ranges could be specified.
-- gpios : (optional) may specify GPIOs in this order: Card-Detect GPIO,
+
+Optional properties:
+- gpios : may specify GPIOs in this order: Card-Detect GPIO,
   Write-Protect GPIO.
+- interrupts : the interrupt of a card detect interrupt.
+- interrupt-parent : the phandle for the interrupt controller that
+  services interrupts for this device.
 
 Example:
 
···
 			 &qe_pio_d 15 0>;
 		voltage-ranges = <3300 3300>;
 		spi-max-frequency = <50000000>;
+		interrupts = <42>;
+		interrupt-parent = <&PIC>;
 	};

drivers/mmc/host/of_mmc_spi.c

···
 struct of_mmc_spi {
 	int gpios[NUM_GPIOS];
 	bool alow_gpios[NUM_GPIOS];
+	int detect_irq;
 	struct mmc_spi_platform_data pdata;
 };
 
···
 static int of_mmc_spi_get_ro(struct device *dev)
 {
 	return of_mmc_spi_read_gpio(dev, WP_GPIO);
+}
+
+static int of_mmc_spi_init(struct device *dev,
+			   irqreturn_t (*irqhandler)(int, void *), void *mmc)
+{
+	struct of_mmc_spi *oms = to_of_mmc_spi(dev);
+
+	return request_threaded_irq(oms->detect_irq, NULL, irqhandler, 0,
+				    dev_name(dev), mmc);
+}
+
+static void of_mmc_spi_exit(struct device *dev, void *mmc)
+{
+	struct of_mmc_spi *oms = to_of_mmc_spi(dev);
+
+	free_irq(oms->detect_irq, mmc);
 }
 
 struct mmc_spi_platform_data *mmc_spi_get_pdata(struct spi_device *spi)
···
 	if (gpio_is_valid(oms->gpios[WP_GPIO]))
 		oms->pdata.get_ro = of_mmc_spi_get_ro;
 
-	/* We don't support interrupts yet, let's poll. */
-	oms->pdata.caps |= MMC_CAP_NEEDS_POLL;
+	oms->detect_irq = irq_of_parse_and_map(np, 0);
+	if (oms->detect_irq != NO_IRQ) {
+		oms->pdata.init = of_mmc_spi_init;
+		oms->pdata.exit = of_mmc_spi_exit;
+	} else {
+		oms->pdata.caps |= MMC_CAP_NEEDS_POLL;
+	}
 
 	dev->platform_data = &oms->pdata;
 	return dev->platform_data;