memory: omap-gpmc: Reserve WAITPIN if needed for WAIT monitoring

If the device attached to GPMC wants to use the WAIT pin
for WAIT monitoring then we reserve it internally for
exclusive use.
Signed-off-by: Roger Quadros <rogerq@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>

drivers/memory/omap-gpmc.c

@@ -1911,6 +1911,8 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
 	const char *name;
 	int ret, cs;
 	u32 val;
+	struct gpio_desc *waitpin_desc = NULL;
+	struct gpmc_device *gpmc = platform_get_drvdata(pdev);
 
 	if (of_property_read_u32(child, "reg", &cs) < 0) {
 		dev_err(&pdev->dev, "%s has no 'reg' property\n",
@@ -2020,16 +2022,30 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
 			goto err;
 	}
 
+	/* Reserve wait pin if it is required and valid */
+	if (gpmc_s.wait_on_read || gpmc_s.wait_on_write) {
+		unsigned int wait_pin = gpmc_s.wait_pin;
+
+		waitpin_desc = gpiochip_request_own_desc(&gpmc->gpio_chip,
+							 wait_pin, "WAITPIN");
+		if (IS_ERR(waitpin_desc)) {
+			dev_err(&pdev->dev, "invalid wait-pin: %d\n", wait_pin);
+			ret = PTR_ERR(waitpin_desc);
+			goto err;
+		}
+	}
+
 	gpmc_cs_show_timings(cs, "before gpmc_cs_program_settings");
+
 	ret = gpmc_cs_program_settings(cs, &gpmc_s);
 	if (ret < 0)
-		goto err;
+		goto err_cs;
 
 	ret = gpmc_cs_set_timings(cs, &gpmc_t, &gpmc_s);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to set gpmc timings for: %s\n",
 			child->name);
-		goto err;
+		goto err_cs;
 	}
 
 	/* Clear limited address i.e. enable A26-A11 */
@@ -2060,6 +2076,10 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
 	dev_err(&pdev->dev, "failed to create gpmc child %s\n", child->name);
 	ret = -ENODEV;
 
+err_cs:
+	if (waitpin_desc)
+		gpiochip_free_own_desc(waitpin_desc);
+
 err:
 	gpmc_cs_free(cs);