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Date:	Fri, 28 Aug 2015 18:45:50 +0100
From:	Mark Brown <broonie@...nel.org>
To:	Markus Pargmann <mpa@...gutronix.de>,
	Mark Brown <broonie@...nel.org>
Cc:	linux-kernel@...r.kernel.org
Subject: Applied "regmap: Introduce max_raw_read/write for regmap_bulk_read/write" to the regmap tree

The patch

   regmap: Introduce max_raw_read/write for regmap_bulk_read/write

has been applied to the regmap tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 9e86b69c3021148d1668db582d3cb3c0c398d001 Mon Sep 17 00:00:00 2001
From: Markus Pargmann <mpa@...gutronix.de>
Date: Thu, 27 Aug 2015 08:44:29 +0200
Subject: [PATCH] regmap: Introduce max_raw_read/write for
 regmap_bulk_read/write

There are some buses which have a limit on the maximum number of bytes
that can be send/received. An example for this is
I2C_FUNC_SMBUS_I2C_BLOCK which does not support any reads/writes of more
than 32 bytes. The regmap_bulk operations should still be able to
utilize the full 32 bytes in this case.

Signed-off-by: Markus Pargmann <mpa@...gutronix.de>
Signed-off-by: Mark Brown <broonie@...nel.org>
---
 drivers/base/regmap/internal.h |  4 ++
 drivers/base/regmap/regmap.c   | 85 ++++++++++++++++++++++++++++++++++--------
 include/linux/regmap.h         |  4 ++
 3 files changed, 78 insertions(+), 15 deletions(-)

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index d744ae3..fc554e3 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -146,6 +146,10 @@ struct regmap {
 	/* if set, the device supports multi write mode */
 	bool can_multi_write;
 
+	/* if set, raw reads/writes are limited to this size */
+	size_t max_raw_read;
+	size_t max_raw_write;
+
 	struct rb_root range_tree;
 	void *selector_work_buf;	/* Scratch buffer used for selector */
 };
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 3496e6a..b8f1578 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -579,6 +579,8 @@ struct regmap *regmap_init(struct device *dev,
 	map->use_single_read = config->use_single_rw || !bus || !bus->read;
 	map->use_single_write = config->use_single_rw || !bus || !bus->write;
 	map->can_multi_write = config->can_multi_write && bus && bus->write;
+	map->max_raw_read = bus->max_raw_read;
+	map->max_raw_write = bus->max_raw_write;
 	map->dev = dev;
 	map->bus = bus;
 	map->bus_context = bus_context;
@@ -1674,6 +1676,7 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
 {
 	int ret = 0, i;
 	size_t val_bytes = map->format.val_bytes;
+	size_t total_size = val_bytes * val_count;
 
 	if (map->bus && !map->format.parse_inplace)
 		return -EINVAL;
@@ -1722,16 +1725,37 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
 		}
 out:
 		map->unlock(map->lock_arg);
-	} else if (map->use_single_write) {
+	} else if (map->use_single_write ||
+		   (map->max_raw_write && map->max_raw_write < total_size)) {
+		int chunk_stride = map->reg_stride;
+		size_t chunk_size = val_bytes;
+		size_t chunk_count = val_count;
+
+		if (!map->use_single_write) {
+			chunk_size = map->max_raw_write;
+			if (chunk_size % val_bytes)
+				chunk_size -= chunk_size % val_bytes;
+			chunk_count = total_size / chunk_size;
+			chunk_stride *= chunk_size / val_bytes;
+		}
+
 		map->lock(map->lock_arg);
-		for (i = 0; i < val_count; i++) {
+		/* Write as many bytes as possible with chunk_size */
+		for (i = 0; i < chunk_count; i++) {
 			ret = _regmap_raw_write(map,
-						reg + (i * map->reg_stride),
-						val + (i * val_bytes),
-						val_bytes);
+						reg + (i * chunk_stride),
+						val + (i * chunk_size),
+						chunk_size);
 			if (ret)
 				break;
 		}
+
+		/* Write remaining bytes */
+		if (!ret && chunk_size * i < total_size) {
+			ret = _regmap_raw_write(map, reg + (i * chunk_stride),
+						val + (i * chunk_size),
+						total_size - i * chunk_size);
+		}
 		map->unlock(map->lock_arg);
 	} else {
 		void *wval;
@@ -2314,20 +2338,51 @@ int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
 		 * Some devices does not support bulk read, for
 		 * them we have a series of single read operations.
 		 */
-		if (map->use_single_read) {
-			for (i = 0; i < val_count; i++) {
-				ret = regmap_raw_read(map,
-						reg + (i * map->reg_stride),
-						val + (i * val_bytes),
-						val_bytes);
-				if (ret != 0)
-					return ret;
-			}
-		} else {
+		size_t total_size = val_bytes * val_count;
+
+		if (!map->use_single_read &&
+		    (!map->max_raw_read || map->max_raw_read > total_size)) {
 			ret = regmap_raw_read(map, reg, val,
 					      val_bytes * val_count);
 			if (ret != 0)
 				return ret;
+		} else {
+			/*
+			 * Some devices do not support bulk read or do not
+			 * support large bulk reads, for them we have a series
+			 * of read operations.
+			 */
+			int chunk_stride = map->reg_stride;
+			size_t chunk_size = val_bytes;
+			size_t chunk_count = val_count;
+
+			if (!map->use_single_read) {
+				chunk_size = map->max_raw_read;
+				if (chunk_size % val_bytes)
+					chunk_size -= chunk_size % val_bytes;
+				chunk_count = total_size / chunk_size;
+				chunk_stride *= chunk_size / val_bytes;
+			}
+
+			/* Read bytes that fit into a multiple of chunk_size */
+			for (i = 0; i < chunk_count; i++) {
+				ret = regmap_raw_read(map,
+						      reg + (i * chunk_stride),
+						      val + (i * chunk_size),
+						      chunk_size);
+				if (ret != 0)
+					return ret;
+			}
+
+			/* Read remaining bytes */
+			if (chunk_size * i < total_size) {
+				ret = regmap_raw_read(map,
+						      reg + (i * chunk_stride),
+						      val + (i * chunk_size),
+						      total_size - i * chunk_size);
+				if (ret != 0)
+					return ret;
+			}
 		}
 
 		for (i = 0; i < val_count * val_bytes; i += val_bytes)
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 73fc34d..327b8f2 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -311,6 +311,8 @@ typedef void (*regmap_hw_free_context)(void *context);
  * @val_format_endian_default: Default endianness for formatted register
  *     values. Used when the regmap_config specifies DEFAULT. If this is
  *     DEFAULT, BIG is assumed.
+ * @max_raw_read: Max raw read size that can be used on the bus.
+ * @max_raw_write: Max raw write size that can be used on the bus.
  */
 struct regmap_bus {
 	bool fast_io;
@@ -325,6 +327,8 @@ struct regmap_bus {
 	u8 read_flag_mask;
 	enum regmap_endian reg_format_endian_default;
 	enum regmap_endian val_format_endian_default;
+	size_t max_raw_read;
+	size_t max_raw_write;
 };
 
 struct regmap *regmap_init(struct device *dev,
-- 
2.5.0

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