regmap-mmio: Add big endian support

Add support for parsing the big-endian device tree property.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

3 files changed, 128 insertions, 41 deletions

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 5b19459828..4c7460fa4c 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -22,4 +22,8 @@ struct regmap {
 	struct cdev cdev;
 };
 
+enum regmap_endian regmap_get_val_endian(struct device_d *dev,
+					 const struct regmap_bus *bus,
+					 const struct regmap_config *config);
+
 #endif
diff --git a/drivers/base/regmap/regmap-mmio.c b/drivers/base/regmap/regmap-mmio.c
index ef6a7db6fd..7ca95d6bea 100644
--- a/drivers/base/regmap/regmap-mmio.c
+++ b/drivers/base/regmap/regmap-mmio.c
@@ -86,6 +86,20 @@ static void regmap_mmio_write32le(struct regmap_mmio_context *ctx,
 	writel(val, ctx->regs + reg);
 }
 
+static void regmap_mmio_write16be(struct regmap_mmio_context *ctx,
+				  unsigned int reg,
+				  unsigned int val)
+{
+	iowrite16be(val, ctx->regs + reg);
+}
+
+static void regmap_mmio_write32be(struct regmap_mmio_context *ctx,
+				  unsigned int reg,
+				  unsigned int val)
+{
+	iowrite32be(val, ctx->regs + reg);
+}
+
 #ifdef CONFIG_64BIT
 static void regmap_mmio_write64le(struct regmap_mmio_context *ctx,
 				  unsigned int reg,
@@ -137,6 +151,18 @@ static unsigned int regmap_mmio_read64le(struct regmap_mmio_context *ctx,
 }
 #endif
 
+static unsigned int regmap_mmio_read16be(struct regmap_mmio_context *ctx,
+				         unsigned int reg)
+{
+	return ioread16be(ctx->regs + reg);
+}
+
+static unsigned int regmap_mmio_read32be(struct regmap_mmio_context *ctx,
+				         unsigned int reg)
+{
+	return ioread32be(ctx->regs + reg);
+}
+
 static int regmap_mmio_read(void *context, unsigned int reg, unsigned int *val)
 {
 	struct regmap_mmio_context *ctx = context;
@@ -156,9 +182,11 @@ static int regmap_mmio_read(void *context, unsigned int reg, unsigned int *val)
 static const struct regmap_bus regmap_mmio = {
 	.reg_write = regmap_mmio_write,
 	.reg_read = regmap_mmio_read,
+	.val_format_endian_default = REGMAP_ENDIAN_LITTLE,
 };
 
-static struct regmap_mmio_context *regmap_mmio_gen_context(void __iomem *regs,
+static struct regmap_mmio_context *regmap_mmio_gen_context(struct device_d *dev,
+					void __iomem *regs,
 					const struct regmap_config *config)
 {
 	struct regmap_mmio_context *ctx;
@@ -184,25 +212,58 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(void __iomem *regs,
 	ctx->regs = regs;
 	ctx->val_bytes = config->val_bits / 8;
 
-	switch (config->val_bits) {
-	case 8:
-		ctx->reg_read = regmap_mmio_read8;
-		ctx->reg_write = regmap_mmio_write8;
-		break;
-	case 16:
-		ctx->reg_read = regmap_mmio_read16le;
-		ctx->reg_write = regmap_mmio_write16le;
-		break;
-	case 32:
-		ctx->reg_read = regmap_mmio_read32le;
-		ctx->reg_write = regmap_mmio_write32le;
-		break;
+	switch (regmap_get_val_endian(dev, &regmap_mmio, config)) {
+	case REGMAP_ENDIAN_DEFAULT:
+	case REGMAP_ENDIAN_LITTLE:
+#ifdef __LITTLE_ENDIAN
+	case REGMAP_ENDIAN_NATIVE:
+#endif
+		switch (config->val_bits) {
+		case 8:
+			ctx->reg_read = regmap_mmio_read8;
+			ctx->reg_write = regmap_mmio_write8;
+			break;
+		case 16:
+			ctx->reg_read = regmap_mmio_read16le;
+			ctx->reg_write = regmap_mmio_write16le;
+			break;
+		case 32:
+			ctx->reg_read = regmap_mmio_read32le;
+			ctx->reg_write = regmap_mmio_write32le;
+			break;
 #ifdef CONFIG_64BIT
-	case 64:
-		ctx->reg_read = regmap_mmio_read64le;
-		ctx->reg_write = regmap_mmio_write64le;
+		case 64:
+			ctx->reg_read = regmap_mmio_read64le;
+			ctx->reg_write = regmap_mmio_write64le;
+			break;
+#endif
+		default:
+			ret = -EINVAL;
+			goto err_free;
+		}
 		break;
+	case REGMAP_ENDIAN_BIG:
+#ifdef __BIG_ENDIAN
+	case REGMAP_ENDIAN_NATIVE:
 #endif
+		switch (config->val_bits) {
+		case 8:
+			ctx->reg_read = regmap_mmio_read8;
+			ctx->reg_write = regmap_mmio_write8;
+			break;
+		case 16:
+			ctx->reg_read = regmap_mmio_read16be;
+			ctx->reg_write = regmap_mmio_write16be;
+			break;
+		case 32:
+			ctx->reg_read = regmap_mmio_read32be;
+			ctx->reg_write = regmap_mmio_write32be;
+			break;
+		default:
+			ret = -EINVAL;
+			goto err_free;
+		}
+		break;
 	default:
 		ret = -EINVAL;
 		goto err_free;
@@ -223,7 +284,7 @@ struct regmap *regmap_init_mmio_clk(struct device_d *dev,
 {
 	struct regmap_mmio_context *ctx;
 
-	ctx = regmap_mmio_gen_context(regs, config);
+	ctx = regmap_mmio_gen_context(dev, regs, config);
 	if (IS_ERR(ctx))
 		return ERR_CAST(ctx);
 
@@ -238,28 +299,6 @@ struct regmap *regmap_init_mmio_clk(struct device_d *dev,
 	return regmap_init(dev, &regmap_mmio, ctx, config);
 }
 
-struct regmap *of_regmap_init_mmio_clk(struct device_node *np,
-				       const char *clk_id,
-				       void __iomem *regs,
-				       const struct regmap_config *config)
-{
-	struct regmap_mmio_context *ctx;
-
-	ctx = regmap_mmio_gen_context(regs, config);
-	if (IS_ERR(ctx))
-		return ERR_CAST(ctx);
-
-	if (clk_id) {
-		ctx->clk = of_clk_get_by_name(np, clk_id);
-		if (IS_ERR(ctx->clk)) {
-			kfree(ctx);
-			return ERR_CAST(ctx->clk);
-		}
-	}
-
-	return regmap_init(NULL, &regmap_mmio, ctx, config);
-}
-
 int regmap_mmio_attach_clk(struct regmap *map, struct clk *clk)
 {
 	struct regmap_mmio_context *ctx = map->bus_context;
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index dc7b4f276f..ee5120fd74 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -28,6 +28,50 @@
 
 static LIST_HEAD(regmaps);
 
+enum regmap_endian regmap_get_val_endian(struct device_d *dev,
+					 const struct regmap_bus *bus,
+					 const struct regmap_config *config)
+{
+	struct device_node *np;
+	enum regmap_endian endian;
+
+	/* Retrieve the endianness specification from the regmap config */
+	endian = config->val_format_endian;
+
+	/* If the regmap config specified a non-default value, use that */
+	if (endian != REGMAP_ENDIAN_DEFAULT)
+		return endian;
+
+	/* If the dev and dev->device_node exist try to get endianness from DT */
+	if (dev && dev->device_node) {
+		np = dev->device_node;
+
+		/* Parse the device's DT node for an endianness specification */
+		if (of_property_read_bool(np, "big-endian"))
+			endian = REGMAP_ENDIAN_BIG;
+		else if (of_property_read_bool(np, "little-endian"))
+			endian = REGMAP_ENDIAN_LITTLE;
+		else if (of_property_read_bool(np, "native-endian"))
+			endian = REGMAP_ENDIAN_NATIVE;
+
+		/* If the endianness was specified in DT, use that */
+		if (endian != REGMAP_ENDIAN_DEFAULT)
+			return endian;
+	}
+
+	/* Retrieve the endianness specification from the bus config */
+	if (bus && bus->val_format_endian_default)
+		endian = bus->val_format_endian_default;
+
+	/* If the bus specified a non-default value, use that */
+	if (endian != REGMAP_ENDIAN_DEFAULT)
+		return endian;
+
+	/* Use this if no other value was found */
+	return REGMAP_ENDIAN_BIG;
+}
+EXPORT_SYMBOL_GPL(regmap_get_val_endian);
+
 /*
  * regmap_init - initialize and register a regmap
  *
@@ -101,7 +145,7 @@ struct regmap *of_node_to_regmap(struct device_node *node)
 	struct regmap *map;
 
 	list_for_each_entry(map, &regmaps, list) {
-		if (map->dev->device_node == node)
+		if (map->dev && map->dev->device_node == node)
 			return map;
 	}