mtd: OneNAND: OMAP2/3: prevent regulator sleeping while OneNAND is in use

Prevent OneNAND's voltage regulator from going to sleep while
OneNAND is in use, by explicitly enabling and disabling the
regulator as appropriate.

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/arch/arm/plat-omap/include/plat/onenand.h b/arch/arm/plat-omap/include/plat/onenand.h
index 72f433d..affe87e 100644
--- a/arch/arm/plat-omap/include/plat/onenand.h
+++ b/arch/arm/plat-omap/include/plat/onenand.h
@@ -23,6 +23,7 @@
 	int                     (*onenand_setup)(void __iomem *, int freq);
 	int			dma_channel;
 	u8			flags;
+	u8			regulator_can_sleep;
 };
 
 #define ONENAND_MAX_PARTITIONS 8
diff --git a/drivers/mtd/onenand/omap2.c b/drivers/mtd/onenand/omap2.c
index 324402f..1a07bfc 100644
--- a/drivers/mtd/onenand/omap2.c
+++ b/drivers/mtd/onenand/omap2.c
@@ -35,6 +35,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/io.h>
 #include <linux/slab.h>
+#include <linux/regulator/consumer.h>
 
 #include <asm/mach/flash.h>
 #include <plat/gpmc.h>
@@ -63,6 +64,7 @@
 	int dma_channel;
 	int freq;
 	int (*setup)(void __iomem *base, int freq);
+	struct regulator *regulator;
 };
 
 #ifdef CONFIG_MTD_PARTITIONS
@@ -601,6 +603,30 @@
 	memset((__force void *)c->onenand.base, 0, ONENAND_BUFRAM_SIZE);
 }
 
+static int omap2_onenand_enable(struct mtd_info *mtd)
+{
+	int ret;
+	struct omap2_onenand *c = container_of(mtd, struct omap2_onenand, mtd);
+
+	ret = regulator_enable(c->regulator);
+	if (ret != 0)
+		dev_err(&c->pdev->dev, "cant enable regulator\n");
+
+	return ret;
+}
+
+static int omap2_onenand_disable(struct mtd_info *mtd)
+{
+	int ret;
+	struct omap2_onenand *c = container_of(mtd, struct omap2_onenand, mtd);
+
+	ret = regulator_disable(c->regulator);
+	if (ret != 0)
+		dev_err(&c->pdev->dev, "cant disable regulator\n");
+
+	return ret;
+}
+
 static int __devinit omap2_onenand_probe(struct platform_device *pdev)
 {
 	struct omap_onenand_platform_data *pdata;
@@ -715,8 +741,18 @@
 		}
 	}
 
+	if (pdata->regulator_can_sleep) {
+		c->regulator = regulator_get(&pdev->dev, "vonenand");
+		if (IS_ERR(c->regulator)) {
+			dev_err(&pdev->dev,  "Failed to get regulator\n");
+			goto err_release_dma;
+		}
+		c->onenand.enable = omap2_onenand_enable;
+		c->onenand.disable = omap2_onenand_disable;
+	}
+
 	if ((r = onenand_scan(&c->mtd, 1)) < 0)
-		goto err_release_dma;
+		goto err_release_regulator;
 
 	switch ((c->onenand.version_id >> 4) & 0xf) {
 	case 0:
@@ -751,6 +787,8 @@
 
 err_release_onenand:
 	onenand_release(&c->mtd);
+err_release_regulator:
+	regulator_put(c->regulator);
 err_release_dma:
 	if (c->dma_channel != -1)
 		omap_free_dma(c->dma_channel);
@@ -777,6 +815,7 @@
 	struct omap2_onenand *c = dev_get_drvdata(&pdev->dev);
 
 	onenand_release(&c->mtd);
+	regulator_put(c->regulator);
 	if (c->dma_channel != -1)
 		omap_free_dma(c->dma_channel);
 	omap2_onenand_shutdown(pdev);