fbdev: sh_mobile_meram: Backup/restore device registers on shutdown/resume

Save and reconfigure the MERAM registers when the MERAM is powered down
and restored

Signed-off-by: Damian Hobson-Garcia <dhobsong@igel.co.jp>

drivers/video/sh_mobile_meram.c

@@ -37,12 +37,31 @@
 #define MEQSEL1 0x40
 #define MEQSEL2 0x44
 
+static unsigned long common_regs[] = {
+	MEVCR1,
+	MEQSEL1,
+	MEQSEL2,
+};
+#define CMN_REGS_SIZE ARRAY_SIZE(common_regs)
+
+static unsigned long icb_regs[] = {
+	MExxCTL,
+	MExxBSIZE,
+	MExxMNCF,
+	MExxSARA,
+	MExxSARB,
+	MExxSBSIZE,
+};
+#define ICB_REGS_SIZE ARRAY_SIZE(icb_regs)
+
 struct sh_mobile_meram_priv {
 	void __iomem	*base;
 	struct mutex	lock;
 	unsigned long	used_icb;
 	int		used_meram_cache_regions;
 	unsigned long	used_meram_cache[SH_MOBILE_MERAM_ICB_NUM];
+	unsigned long	cmn_saved_regs[CMN_REGS_SIZE];
+	unsigned long	icb_saved_regs[ICB_REGS_SIZE * SH_MOBILE_MERAM_ICB_NUM];
 };
 
 /* settings */
@@ -469,6 +488,57 @@ static int sh_mobile_meram_update(struct sh_mobile_meram_info *pdata,
 	return 0;
 }
 
+static int sh_mobile_meram_runtime_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct sh_mobile_meram_priv *priv = platform_get_drvdata(pdev);
+	int k, j;
+
+	for (k = 0; k < CMN_REGS_SIZE; k++)
+		priv->cmn_saved_regs[k] = meram_read_reg(priv->base,
+			common_regs[k]);
+
+	for (j = 0; j < 32; j++) {
+		if (!test_bit(j, &priv->used_icb))
+			continue;
+		for (k = 0; k < ICB_REGS_SIZE; k++) {
+			priv->icb_saved_regs[j * ICB_REGS_SIZE + k] =
+				meram_read_icb(priv->base, j, icb_regs[k]);
+			/* Reset ICB on resume */
+			if (icb_regs[k] == MExxCTL)
+				priv->icb_saved_regs[j * ICB_REGS_SIZE + k] =
+					0x70;
+		}
+	}
+	return 0;
+}
+
+static int sh_mobile_meram_runtime_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct sh_mobile_meram_priv *priv = platform_get_drvdata(pdev);
+	int k, j;
+
+	for (j = 0; j < 32; j++) {
+		if (!test_bit(j, &priv->used_icb))
+			continue;
+		for (k = 0; k < ICB_REGS_SIZE; k++) {
+			meram_write_icb(priv->base, j, icb_regs[k],
+			priv->icb_saved_regs[j * ICB_REGS_SIZE + k]);
+		}
+	}
+
+	for (k = 0; k < CMN_REGS_SIZE; k++)
+		meram_write_reg(priv->base, common_regs[k],
+			priv->cmn_saved_regs[k]);
+	return 0;
+}
+
+static const struct dev_pm_ops sh_mobile_meram_dev_pm_ops = {
+	.runtime_suspend = sh_mobile_meram_runtime_suspend,
+	.runtime_resume = sh_mobile_meram_runtime_resume,
+};
+
 static struct sh_mobile_meram_ops sh_mobile_meram_ops = {
 	.module			= THIS_MODULE,
 	.meram_register		= sh_mobile_meram_register,
@@ -557,6 +627,7 @@ static struct platform_driver sh_mobile_meram_driver = {
 	.driver	= {
 		.name		= "sh_mobile_meram",
 		.owner		= THIS_MODULE,
+		.pm		= &sh_mobile_meram_dev_pm_ops,
 	},
 	.probe		= sh_mobile_meram_probe,
 	.remove		= sh_mobile_meram_remove,