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>

arch/arm/plat-omap/include/plat/onenand.h

@@ -23,6 +23,7 @@ struct omap_onenand_platform_data {
 	int                     (*onenand_setup)(void __iomem *, int freq);
 	int			dma_channel;
 	u8			flags;
+	u8			regulator_can_sleep;
 };
 
 #define ONENAND_MAX_PARTITIONS 8

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 @@ struct omap2_onenand {
 	int dma_channel;
 	int freq;
 	int (*setup)(void __iomem *base, int freq);
+	struct regulator *regulator;
 };
 
 #ifdef CONFIG_MTD_PARTITIONS
@@ -601,6 +603,30 @@ static void omap2_onenand_shutdown(struct platform_device *pdev)
 	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 @@ static int __devinit omap2_onenand_probe(struct platform_device *pdev)
 		}
 	}
 
-	if ((r = onenand_scan(&c->mtd, 1)) < 0)
+	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_regulator;
 
 	switch ((c->onenand.version_id >> 4) & 0xf) {
 	case 0:
@@ -751,6 +787,8 @@ static int __devinit omap2_onenand_probe(struct platform_device *pdev)
 
 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 @@ static int __devexit omap2_onenand_remove(struct platform_device *pdev)
 	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);