[PATCH v2 3/4] regmap: mmio: Introduce IO accessors that can talk to IO port

[Andy Shevchenko]

Some users may use regmap MMIO for IO ports, and this can be done
by assigning ioreadXX()/iowriteXX() and their Big Endian counterparts
to the regmap context.

Add IO port support with a corresponding flag added.

While doing that, make sure that user won't select relaxed MMIO access
along with IO port because the latter have no relaxed variants.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
 drivers/base/regmap/regmap-mmio.c | 105 +++++++++++++++++++++++++++---
 include/linux/regmap.h            |   3 +
 2 files changed, 99 insertions(+), 9 deletions(-)

diff --git a/drivers/base/regmap/regmap-mmio.c b/drivers/base/regmap/regmap-mmio.c
index b1bd93ea405e..37f79e912d01 100644
--- a/drivers/base/regmap/regmap-mmio.c
+++ b/drivers/base/regmap/regmap-mmio.c
@@ -74,6 +74,12 @@ static void regmap_mmio_write8_relaxed(struct regmap_mmio_context *ctx,
 	writeb_relaxed(val, ctx->regs + reg);
 }
 
+static void regmap_mmio_iowrite8(struct regmap_mmio_context *ctx,
+				 unsigned int reg, unsigned int val)
+{
+	iowrite8(val, ctx->regs + reg);
+}
+
 static void regmap_mmio_write16le(struct regmap_mmio_context *ctx,
 				  unsigned int reg,
 				  unsigned int val)
@@ -88,6 +94,12 @@ static void regmap_mmio_write16le_relaxed(struct regmap_mmio_context *ctx,
 	writew_relaxed(val, ctx->regs + reg);
 }
 
+static void regmap_mmio_iowrite16le(struct regmap_mmio_context *ctx,
+				    unsigned int reg, unsigned int val)
+{
+	iowrite16(val, ctx->regs + reg);
+}
+
 static void regmap_mmio_write16be(struct regmap_mmio_context *ctx,
 				  unsigned int reg,
 				  unsigned int val)
@@ -95,6 +107,12 @@ static void regmap_mmio_write16be(struct regmap_mmio_context *ctx,
 	iowrite16be(val, ctx->regs + reg);
 }
 
+static void regmap_mmio_iowrite16be(struct regmap_mmio_context *ctx,
+				    unsigned int reg, unsigned int val)
+{
+	iowrite16be(val, ctx->regs + reg);
+}
+
 static void regmap_mmio_write32le(struct regmap_mmio_context *ctx,
 				  unsigned int reg,
 				  unsigned int val)
@@ -109,6 +127,12 @@ static void regmap_mmio_write32le_relaxed(struct regmap_mmio_context *ctx,
 	writel_relaxed(val, ctx->regs + reg);
 }
 
+static void regmap_mmio_iowrite32le(struct regmap_mmio_context *ctx,
+				    unsigned int reg, unsigned int val)
+{
+	iowrite32(val, ctx->regs + reg);
+}
+
 static void regmap_mmio_write32be(struct regmap_mmio_context *ctx,
 				  unsigned int reg,
 				  unsigned int val)
@@ -116,6 +140,12 @@ static void regmap_mmio_write32be(struct regmap_mmio_context *ctx,
 	iowrite32be(val, ctx->regs + reg);
 }
 
+static void regmap_mmio_iowrite32be(struct regmap_mmio_context *ctx,
+				    unsigned int reg, unsigned int val)
+{
+	iowrite32be(val, ctx->regs + reg);
+}
+
 static int regmap_mmio_write(void *context, unsigned int reg, unsigned int val)
 {
 	struct regmap_mmio_context *ctx = context;
@@ -147,6 +177,12 @@ static unsigned int regmap_mmio_read8_relaxed(struct regmap_mmio_context *ctx,
 	return readb_relaxed(ctx->regs + reg);
 }
 
+static unsigned int regmap_mmio_ioread8(struct regmap_mmio_context *ctx,
+					unsigned int reg)
+{
+	return ioread8(ctx->regs + reg);
+}
+
 static unsigned int regmap_mmio_read16le(struct regmap_mmio_context *ctx,
 				         unsigned int reg)
 {
@@ -159,12 +195,24 @@ static unsigned int regmap_mmio_read16le_relaxed(struct regmap_mmio_context *ctx
 	return readw_relaxed(ctx->regs + reg);
 }
 
+static unsigned int regmap_mmio_ioread16le(struct regmap_mmio_context *ctx,
+					   unsigned int reg)
+{
+	return ioread16(ctx->regs + reg);
+}
+
 static unsigned int regmap_mmio_read16be(struct regmap_mmio_context *ctx,
 				         unsigned int reg)
 {
 	return ioread16be(ctx->regs + reg);
 }
 
+static unsigned int regmap_mmio_ioread16be(struct regmap_mmio_context *ctx,
+					   unsigned int reg)
+{
+	return ioread16be(ctx->regs + reg);
+}
+
 static unsigned int regmap_mmio_read32le(struct regmap_mmio_context *ctx,
 				         unsigned int reg)
 {
@@ -177,12 +225,24 @@ static unsigned int regmap_mmio_read32le_relaxed(struct regmap_mmio_context *ctx
 	return readl_relaxed(ctx->regs + reg);
 }
 
+static unsigned int regmap_mmio_ioread32le(struct regmap_mmio_context *ctx,
+					   unsigned int reg)
+{
+	return ioread32(ctx->regs + reg);
+}
+
 static unsigned int regmap_mmio_read32be(struct regmap_mmio_context *ctx,
 				         unsigned int reg)
 {
 	return ioread32be(ctx->regs + reg);
 }
 
+static unsigned int regmap_mmio_ioread32be(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;
@@ -245,6 +305,9 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
 	if (config->reg_stride < min_stride)
 		return ERR_PTR(-EINVAL);
 
+	if (config->use_relaxed_mmio && config->io_port)
+		return ERR_PTR(-EINVAL);
+
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
 		return ERR_PTR(-ENOMEM);
@@ -261,7 +324,10 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
 #endif
 		switch (config->val_bits) {
 		case 8:
-			if (config->use_relaxed_mmio) {
+			if (config->io_port) {
+				ctx->reg_read = regmap_mmio_ioread8;
+				ctx->reg_write = regmap_mmio_iowrite8;
+			} else if (config->use_relaxed_mmio) {
 				ctx->reg_read = regmap_mmio_read8_relaxed;
 				ctx->reg_write = regmap_mmio_write8_relaxed;
 			} else {
@@ -270,7 +336,10 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
 			}
 			break;
 		case 16:
-			if (config->use_relaxed_mmio) {
+			if (config->io_port) {
+				ctx->reg_read = regmap_mmio_ioread16le;
+				ctx->reg_write = regmap_mmio_iowrite16le;
+			} else if (config->use_relaxed_mmio) {
 				ctx->reg_read = regmap_mmio_read16le_relaxed;
 				ctx->reg_write = regmap_mmio_write16le_relaxed;
 			} else {
@@ -279,7 +348,10 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
 			}
 			break;
 		case 32:
-			if (config->use_relaxed_mmio) {
+			if (config->io_port) {
+				ctx->reg_read = regmap_mmio_ioread32le;
+				ctx->reg_write = regmap_mmio_iowrite32le;
+			} else if (config->use_relaxed_mmio) {
 				ctx->reg_read = regmap_mmio_read32le_relaxed;
 				ctx->reg_write = regmap_mmio_write32le_relaxed;
 			} else {
@@ -298,16 +370,31 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
 #endif
 		switch (config->val_bits) {
 		case 8:
-			ctx->reg_read = regmap_mmio_read8;
-			ctx->reg_write = regmap_mmio_write8;
+			if (config->io_port) {
+				ctx->reg_read = regmap_mmio_ioread8;
+				ctx->reg_write = regmap_mmio_iowrite8;
+			} else {
+				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;
+			if (config->io_port) {
+				ctx->reg_read = regmap_mmio_ioread16be;
+				ctx->reg_write = regmap_mmio_iowrite16be;
+			} else {
+				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;
+			if (config->io_port) {
+				ctx->reg_read = regmap_mmio_ioread32be;
+				ctx->reg_write = regmap_mmio_iowrite32be;
+			} else {
+				ctx->reg_read = regmap_mmio_read32be;
+				ctx->reg_write = regmap_mmio_write32be;
+			}
 			break;
 		default:
 			ret = -EINVAL;
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 7cf2157134ac..8cccc247cd37 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -311,6 +311,8 @@ typedef void (*regmap_unlock)(void *);
  *		  This field is a duplicate of a similar file in
  *		  'struct regmap_bus' and serves exact same purpose.
  *		   Use it only for "no-bus" cases.
+ * @io_port:	  Support IO port accessors. Makes sense only when MMIO vs. IO port
+ *		  access can be distinguished.
  * @max_register: Optional, specifies the maximum valid register address.
  * @wr_table:     Optional, points to a struct regmap_access_table specifying
  *                valid ranges for write access.
@@ -399,6 +401,7 @@ struct regmap_config {
 	size_t max_raw_write;
 
 	bool fast_io;
+	bool io_port;
 
 	unsigned int max_register;
 	const struct regmap_access_table *wr_table;
-- 
2.35.1