[PATCH v2] mmc: mmci.c: Defer probe() in case of yet uninitialized GPIOs

[Roland Stigge]

If the GPIOs used by the MMCI driver are not registered yet when the driver is
probe()d, they can't be used. This happens if the mmci driver is probed before
the respective GPIO controller (e.g. on the LPC32xx EA3250 board, the PCA9532
GPIO controller would be initialized via DT after mmci). Therefore, we defer
mmci in this case.

Signed-off-by: Roland Stigge <stigge at antcom.de>

---
 drivers/mmc/host/mmci.c |   30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

--- linux-2.6.orig/drivers/mmc/host/mmci.c
+++ linux-2.6/drivers/mmc/host/mmci.c
@@ -1215,13 +1215,21 @@ static void mmci_dt_populate_generic_pda
 {
 	int bus_width = 0;
 
-	pdata->gpio_wp = of_get_named_gpio(np, "wp-gpios", 0);
-	if (!pdata->gpio_wp)
-		pdata->gpio_wp = -1;
-
-	pdata->gpio_cd = of_get_named_gpio(np, "cd-gpios", 0);
-	if (!pdata->gpio_cd)
-		pdata->gpio_cd = -1;
+	if (of_get_property(np, "wp-gpios", NULL)) {
+		pdata->gpio_wp = of_get_named_gpio(np, "wp-gpios", 0);
+		if (pdata->gpio_wp == -ENODEV)
+			pdata->gpio_wp = -EPROBE_DEFER;
+	} else {
+		pdata->gpio_wp = -ENODEV;
+	}
+
+	if (of_get_property(np, "cd-gpios", NULL)) {
+		pdata->gpio_cd = of_get_named_gpio(np, "cd-gpios", 0);
+		if (pdata->gpio_cd == -ENODEV)
+			pdata->gpio_cd = -EPROBE_DEFER;
+	} else {
+		pdata->gpio_cd = -ENODEV;
+	}
 
 	if (of_get_property(np, "cd-inverted", NULL))
 		pdata->cd_invert = true;
@@ -1424,6 +1432,10 @@ static int __devinit mmci_probe(struct a
 	writel(0, host->base + MMCIMASK1);
 	writel(0xfff, host->base + MMCICLEAR);
 
+	if (plat->gpio_cd == -EPROBE_DEFER) {
+		ret = -EPROBE_DEFER;
+		goto err_gpio_cd;
+	}
 	if (gpio_is_valid(plat->gpio_cd)) {
 		ret = gpio_request(plat->gpio_cd, DRIVER_NAME " (cd)");
 		if (ret == 0)
@@ -1447,6 +1459,10 @@ static int __devinit mmci_probe(struct a
 		if (ret >= 0)
 			host->gpio_cd_irq = gpio_to_irq(plat->gpio_cd);
 	}
+	if (plat->gpio_wp == -EPROBE_DEFER) {
+		ret = -EPROBE_DEFER;
+		goto err_gpio_wp;
+	}
 	if (gpio_is_valid(plat->gpio_wp)) {
 		ret = gpio_request(plat->gpio_wp, DRIVER_NAME " (wp)");
 		if (ret == 0)