[PATCH RFC 0/7] eeprom: at24: switch driver to regmap_i2c

[PATCH RFC 0/7] eeprom: at24: switch driver to regmap_i2c

[Heiner Kallweit]

Using regmap_i2c allows us to get rid of dealing with the low-level
differences between I2C and SMBUS. As a result the code can be
simplified a lot.

This patchset was successfully tested with a 24C32 on a I2C adapter.

Heiner Kallweit (7):
  eeprom: at24: add basic regmap_i2c support
  eeprom: at24: change at24_translate_offset return type
  eeprom: at24: add regmap-based write function
  eeprom: at24: remove old write functions
  eeprom: at24: add regmap-based read functions
  eeprom: at24: remove old read functions
  eeprom: at24: remove now unneeded smbus-related code

 drivers/misc/eeprom/Kconfig |   1 +
 drivers/misc/eeprom/at24.c  | 381 +++++++++-----------------------------------
 2 files changed, 77 insertions(+), 305 deletions(-)

-- 
2.14.1

[PATCH RFC 1/7] eeprom: at24: add basic regmap_i2c support

[Heiner Kallweit]

This patch adds basic regmap support to be used by subsequent
patches of this series.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/misc/eeprom/Kconfig |  1 +
 drivers/misc/eeprom/at24.c  | 53 +++++++++++++++++++++++++++++++++++----------
 2 files changed, 43 insertions(+), 11 deletions(-)

diff --git a/drivers/misc/eeprom/Kconfig b/drivers/misc/eeprom/Kconfig
index de587620..68a1ac92 100644
--- a/drivers/misc/eeprom/Kconfig
+++ b/drivers/misc/eeprom/Kconfig
@@ -4,6 +4,7 @@ config EEPROM_AT24
 	tristate "I2C EEPROMs / RAMs / ROMs from most vendors"
 	depends on I2C && SYSFS
 	select NVMEM
+	select REGMAP_I2C
 	help
 	  Enable this driver to get read/write support to most I2C EEPROMs
 	  and compatible devices like FRAMs, SRAMs, ROMs etc. After you
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 764ff5df..e615bafa 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -23,6 +23,7 @@
 #include <linux/acpi.h>
 #include <linux/i2c.h>
 #include <linux/nvmem-provider.h>
+#include <linux/regmap.h>
 #include <linux/platform_data/at24.h>
 
 /*
@@ -53,6 +54,11 @@
  * which won't work on pure SMBus systems.
  */
 
+struct at24_client {
+	struct i2c_client *client;
+	struct regmap *regmap;
+};
+
 struct at24_data {
 	struct at24_platform_data chip;
 	int use_smbus;
@@ -79,7 +85,7 @@ struct at24_data {
 	 * Some chips tie up multiple I2C addresses; dummy devices reserve
 	 * them for us, and we'll use them with SMBus calls.
 	 */
-	struct i2c_client *client[];
+	struct at24_client client[];
 };
 
 /*
@@ -214,7 +220,7 @@ static struct i2c_client *at24_translate_offset(struct at24_data *at24,
 		*offset &= 0xff;
 	}
 
-	return at24->client[i];
+	return at24->client[i].client;
 }
 
 static ssize_t at24_eeprom_read_smbus(struct at24_data *at24, char *buf,
@@ -583,6 +589,16 @@ static void at24_get_pdata(struct device *dev, struct at24_platform_data *chip)
 	}
 }
 
+static const struct regmap_config regmap_config_8 = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static const struct regmap_config regmap_config_16 = {
+	.reg_bits = 16,
+	.val_bits = 8,
+};
+
 static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
 	struct at24_platform_data chip;
@@ -593,6 +609,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	struct at24_data *at24;
 	int err;
 	unsigned i, num_addresses;
+	const struct regmap_config *config;
 	u8 test_byte;
 
 	if (client->dev.platform_data) {
@@ -665,8 +682,13 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		num_addresses =	DIV_ROUND_UP(chip.byte_len,
 			(chip.flags & AT24_FLAG_ADDR16) ? 65536 : 256);
 
+	if (chip.flags & AT24_FLAG_ADDR16)
+		config = &regmap_config_16;
+	else
+		config = &regmap_config_8;
+
 	at24 = devm_kzalloc(&client->dev, sizeof(struct at24_data) +
-		num_addresses * sizeof(struct i2c_client *), GFP_KERNEL);
+		num_addresses * sizeof(struct at24_client), GFP_KERNEL);
 	if (!at24)
 		return -ENOMEM;
 
@@ -676,6 +698,11 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	at24->chip = chip;
 	at24->num_addresses = num_addresses;
 
+	at24->client[0].client = client;
+	at24->client[0].regmap = devm_regmap_init_i2c(client, config);
+	if (IS_ERR(at24->client[0].regmap))
+		return PTR_ERR(at24->client[0].regmap);
+
 	if ((chip.flags & AT24_FLAG_SERIAL) && (chip.flags & AT24_FLAG_MAC)) {
 		dev_err(&client->dev,
 			"invalid device data - cannot have both AT24_FLAG_SERIAL & AT24_FLAG_MAC.");
@@ -723,18 +750,22 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		}
 	}
 
-	at24->client[0] = client;
-
 	/* use dummy devices for multiple-address chips */
 	for (i = 1; i < num_addresses; i++) {
-		at24->client[i] = i2c_new_dummy(client->adapter,
-					client->addr + i);
-		if (!at24->client[i]) {
+		at24->client[i].client = i2c_new_dummy(client->adapter,
+						       client->addr + i);
+		if (!at24->client[i].client) {
 			dev_err(&client->dev, "address 0x%02x unavailable\n",
 					client->addr + i);
 			err = -EADDRINUSE;
 			goto err_clients;
 		}
+		at24->client[i].regmap = devm_regmap_init_i2c(
+					at24->client[i].client, config);
+		if (IS_ERR(at24->client[i].regmap)) {
+			err = PTR_ERR(at24->client[i].regmap);
+			goto err_clients;
+		}
 	}
 
 	i2c_set_clientdata(client, at24);
@@ -788,8 +819,8 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
 err_clients:
 	for (i = 1; i < num_addresses; i++)
-		if (at24->client[i])
-			i2c_unregister_device(at24->client[i]);
+		if (at24->client[i].client)
+			i2c_unregister_device(at24->client[i].client);
 
 	return err;
 }
@@ -804,7 +835,7 @@ static int at24_remove(struct i2c_client *client)
 	nvmem_unregister(at24->nvmem);
 
 	for (i = 1; i < at24->num_addresses; i++)
-		i2c_unregister_device(at24->client[i]);
+		i2c_unregister_device(at24->client[i].client);
 
 	return 0;
 }
-- 
2.14.1

[PATCH RFC 2/7] eeprom: at24: change at24_translate_offset return type

[Heiner Kallweit]

Change return type of at24_translate_offset to *at24_client to make
member regmap accessible for subsequent patches of this series.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/misc/eeprom/at24.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index e615bafa..7cd746de 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -207,8 +207,8 @@ MODULE_DEVICE_TABLE(acpi, at24_acpi_ids);
  * one "eeprom" file not four, but larger reads would fail when
  * they crossed certain pages.
  */
-static struct i2c_client *at24_translate_offset(struct at24_data *at24,
-						unsigned int *offset)
+static struct at24_client *at24_translate_offset(struct at24_data *at24,
+						 unsigned int *offset)
 {
 	unsigned i;
 
@@ -220,7 +220,7 @@ static struct i2c_client *at24_translate_offset(struct at24_data *at24,
 		*offset &= 0xff;
 	}
 
-	return at24->client[i].client;
+	return &at24->client[i];
 }
 
 static ssize_t at24_eeprom_read_smbus(struct at24_data *at24, char *buf,
@@ -230,7 +230,7 @@ static ssize_t at24_eeprom_read_smbus(struct at24_data *at24, char *buf,
 	struct i2c_client *client;
 	int status;
 
-	client = at24_translate_offset(at24, &offset);
+	client = at24_translate_offset(at24, &offset)->client;
 
 	if (count > io_limit)
 		count = io_limit;
@@ -264,7 +264,7 @@ static ssize_t at24_eeprom_read_i2c(struct at24_data *at24, char *buf,
 	u8 msgbuf[2];
 
 	memset(msg, 0, sizeof(msg));
-	client = at24_translate_offset(at24, &offset);
+	client = at24_translate_offset(at24, &offset)->client;
 
 	if (count > io_limit)
 		count = io_limit;
@@ -313,7 +313,7 @@ static ssize_t at24_eeprom_read_serial(struct at24_data *at24, char *buf,
 	u8 addrbuf[2];
 	int status;
 
-	client = at24_translate_offset(at24, &offset);
+	client = at24_translate_offset(at24, &offset)->client;
 
 	memset(msg, 0, sizeof(msg));
 	msg[0].addr = client->addr;
@@ -366,7 +366,7 @@ static ssize_t at24_eeprom_read_mac(struct at24_data *at24, char *buf,
 	u8 addrbuf[2];
 	int status;
 
-	client = at24_translate_offset(at24, &offset);
+	client = at24_translate_offset(at24, &offset)->client;
 
 	memset(msg, 0, sizeof(msg));
 	msg[0].addr = client->addr;
@@ -421,7 +421,7 @@ static ssize_t at24_eeprom_write_smbus_block(struct at24_data *at24,
 	struct i2c_client *client;
 	ssize_t status = 0;
 
-	client = at24_translate_offset(at24, &offset);
+	client = at24_translate_offset(at24, &offset)->client;
 	count = at24_adjust_write_count(at24, offset, count);
 
 	loop_until_timeout(timeout, write_time) {
@@ -448,7 +448,7 @@ static ssize_t at24_eeprom_write_smbus_byte(struct at24_data *at24,
 	struct i2c_client *client;
 	ssize_t status = 0;
 
-	client = at24_translate_offset(at24, &offset);
+	client = at24_translate_offset(at24, &offset)->client;
 
 	loop_until_timeout(timeout, write_time) {
 		status = i2c_smbus_write_byte_data(client, offset, buf[0]);
@@ -474,7 +474,7 @@ static ssize_t at24_eeprom_write_i2c(struct at24_data *at24, const char *buf,
 	ssize_t status = 0;
 	int i = 0;
 
-	client = at24_translate_offset(at24, &offset);
+	client = at24_translate_offset(at24, &offset)->client;
 	count = at24_adjust_write_count(at24, offset, count);
 
 	msg.addr = client->addr;
-- 
2.14.1

[PATCH RFC 3/7] eeprom: at24: add regmap-based write function

[Heiner Kallweit]

Add a regmap-based write function.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/misc/eeprom/at24.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 7cd746de..4e4225b2 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -465,6 +465,22 @@ static ssize_t at24_eeprom_write_smbus_byte(struct at24_data *at24,
 	return -ETIMEDOUT;
 }
 
+static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf,
+				 unsigned int offset, size_t count)
+{
+	unsigned long timeout, write_time;
+	struct regmap *regmap;
+
+	regmap = at24_translate_offset(at24, &offset)->regmap;
+	count = at24_adjust_write_count(at24, offset, count);
+
+	loop_until_timeout(timeout, write_time)
+		if (!regmap_bulk_write(regmap, offset, buf, count))
+			return count;
+
+	return -ETIMEDOUT;
+}
+
 static ssize_t at24_eeprom_write_i2c(struct at24_data *at24, const char *buf,
 				     unsigned int offset, size_t count)
 {
@@ -553,7 +569,7 @@ static int at24_write(void *priv, unsigned int off, void *val, size_t count)
 	while (count) {
 		int status;
 
-		status = at24->write_func(at24, buf, off, count);
+		status = at24_regmap_write(at24, buf, off, count);
 		if (status < 0) {
 			mutex_unlock(&at24->lock);
 			return status;
-- 
2.14.1

[PATCH RFC 4/7] eeprom: at24: remove old write functions

[Heiner Kallweit]

Remove the old and now unused write functions.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/misc/eeprom/at24.c | 111 ---------------------------------------------
 1 file changed, 111 deletions(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 4e4225b2..6c5e5538 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -62,11 +62,8 @@ struct at24_client {
 struct at24_data {
 	struct at24_platform_data chip;
 	int use_smbus;
-	int use_smbus_write;
 
 	ssize_t (*read_func)(struct at24_data *, char *, unsigned int, size_t);
-	ssize_t (*write_func)(struct at24_data *,
-			      const char *, unsigned int, size_t);
 
 	/*
 	 * Lock protects against activities from other Linux tasks,
@@ -74,7 +71,6 @@ struct at24_data {
 	 */
 	struct mutex lock;
 
-	u8 *writebuf;
 	unsigned write_max;
 	unsigned num_addresses;
 
@@ -413,58 +409,6 @@ static size_t at24_adjust_write_count(struct at24_data *at24,
 	return count;
 }
 
-static ssize_t at24_eeprom_write_smbus_block(struct at24_data *at24,
-					     const char *buf,
-					     unsigned int offset, size_t count)
-{
-	unsigned long timeout, write_time;
-	struct i2c_client *client;
-	ssize_t status = 0;
-
-	client = at24_translate_offset(at24, &offset)->client;
-	count = at24_adjust_write_count(at24, offset, count);
-
-	loop_until_timeout(timeout, write_time) {
-		status = i2c_smbus_write_i2c_block_data(client,
-							offset, count, buf);
-		if (status == 0)
-			status = count;
-
-		dev_dbg(&client->dev, "write %zu@%d --> %zd (%ld)\n",
-				count, offset, status, jiffies);
-
-		if (status == count)
-			return count;
-	}
-
-	return -ETIMEDOUT;
-}
-
-static ssize_t at24_eeprom_write_smbus_byte(struct at24_data *at24,
-					    const char *buf,
-					    unsigned int offset, size_t count)
-{
-	unsigned long timeout, write_time;
-	struct i2c_client *client;
-	ssize_t status = 0;
-
-	client = at24_translate_offset(at24, &offset)->client;
-
-	loop_until_timeout(timeout, write_time) {
-		status = i2c_smbus_write_byte_data(client, offset, buf[0]);
-		if (status == 0)
-			status = count;
-
-		dev_dbg(&client->dev, "write %zu@%d --> %zd (%ld)\n",
-				count, offset, status, jiffies);
-
-		if (status == count)
-			return count;
-	}
-
-	return -ETIMEDOUT;
-}
-
 static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf,
 				 unsigned int offset, size_t count)
 {
@@ -481,45 +425,6 @@ static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf,
 	return -ETIMEDOUT;
 }
 
-static ssize_t at24_eeprom_write_i2c(struct at24_data *at24, const char *buf,
-				     unsigned int offset, size_t count)
-{
-	unsigned long timeout, write_time;
-	struct i2c_client *client;
-	struct i2c_msg msg;
-	ssize_t status = 0;
-	int i = 0;
-
-	client = at24_translate_offset(at24, &offset)->client;
-	count = at24_adjust_write_count(at24, offset, count);
-
-	msg.addr = client->addr;
-	msg.flags = 0;
-
-	/* msg.buf is u8 and casts will mask the values */
-	msg.buf = at24->writebuf;
-	if (at24->chip.flags & AT24_FLAG_ADDR16)
-		msg.buf[i++] = offset >> 8;
-
-	msg.buf[i++] = offset;
-	memcpy(&msg.buf[i], buf, count);
-	msg.len = i + count;
-
-	loop_until_timeout(timeout, write_time) {
-		status = i2c_transfer(client->adapter, &msg, 1);
-		if (status == 1)
-			status = count;
-
-		dev_dbg(&client->dev, "write %zu@%d --> %zd (%ld)\n",
-				count, offset, status, jiffies);
-
-		if (status == count)
-			return count;
-	}
-
-	return -ETIMEDOUT;
-}
-
 static int at24_read(void *priv, unsigned int off, void *val, size_t count)
 {
 	struct at24_data *at24 = priv;
@@ -710,7 +615,6 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
 	mutex_init(&at24->lock);
 	at24->use_smbus = use_smbus;
-	at24->use_smbus_write = use_smbus_write;
 	at24->chip = chip;
 	at24->num_addresses = num_addresses;
 
@@ -734,15 +638,6 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 						  : at24_eeprom_read_i2c;
 	}
 
-	if (at24->use_smbus) {
-		if (at24->use_smbus_write == I2C_SMBUS_I2C_BLOCK_DATA)
-			at24->write_func = at24_eeprom_write_smbus_block;
-		else
-			at24->write_func = at24_eeprom_write_smbus_byte;
-	} else {
-		at24->write_func = at24_eeprom_write_i2c;
-	}
-
 	writable = !(chip.flags & AT24_FLAG_READONLY);
 	if (writable) {
 		if (!use_smbus || use_smbus_write) {
@@ -754,12 +649,6 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 			if (use_smbus && write_max > I2C_SMBUS_BLOCK_MAX)
 				write_max = I2C_SMBUS_BLOCK_MAX;
 			at24->write_max = write_max;
-
-			/* buffer (data + address at the beginning) */
-			at24->writebuf = devm_kzalloc(&client->dev,
-				write_max + 2, GFP_KERNEL);
-			if (!at24->writebuf)
-				return -ENOMEM;
 		} else {
 			dev_warn(&client->dev,
 				"cannot write due to controller restrictions.");
-- 
2.14.1

[PATCH RFC 5/7] eeprom: at24: add regmap-based read functions

[Heiner Kallweit]

Add regmap-based read functions.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/misc/eeprom/at24.c | 58 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 57 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 6c5e5538..55b35007 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -250,6 +250,59 @@ static ssize_t at24_eeprom_read_smbus(struct at24_data *at24, char *buf,
 	return -ETIMEDOUT;
 }
 
+static ssize_t at24_regmap_read(struct at24_data *at24, char *buf,
+				unsigned int offset, size_t count)
+{
+	unsigned long timeout, read_time;
+	struct regmap *regmap;
+
+	regmap = at24_translate_offset(at24, &offset)->regmap;
+
+	if (count > io_limit)
+		count = io_limit;
+
+	if (at24->chip.flags & AT24_FLAG_MAC)
+		offset += 0x90;
+
+	loop_until_timeout(timeout, read_time)
+		if (!regmap_bulk_read(regmap, offset, buf, count))
+			return count;
+
+	return -ETIMEDOUT;
+}
+
+static ssize_t at24_regmap_read_serial(struct at24_data *at24, char *buf,
+				       unsigned int offset, size_t count)
+{
+	unsigned long timeout, read_time;
+	struct regmap *regmap;
+
+	regmap = at24_translate_offset(at24, &offset)->regmap;
+
+	if (count > io_limit)
+		count = io_limit;
+
+	if (at24->chip.flags & AT24_FLAG_ADDR16)
+		/*
+		 * For 16 bit address pointers, the word address must contain
+		 * a '10' sequence in bits 11 and 10 regardless of the
+		 * intended position of the address pointer.
+		 */
+		offset |= BIT(11);
+	else
+		/*
+		 * Otherwise the word address must begin with a '10' sequence,
+		 * regardless of the intended address.
+		 */
+		offset |= BIT(7);
+
+	loop_until_timeout(timeout, read_time)
+		if (!regmap_bulk_read(regmap, offset, buf, count))
+			return count;
+
+	return -ETIMEDOUT;
+}
+
 static ssize_t at24_eeprom_read_i2c(struct at24_data *at24, char *buf,
 				    unsigned int offset, size_t count)
 {
@@ -442,7 +495,10 @@ static int at24_read(void *priv, unsigned int off, void *val, size_t count)
 	while (count) {
 		int	status;
 
-		status = at24->read_func(at24, buf, off, count);
+		if (at24->chip.flags & AT24_FLAG_SERIAL)
+			status = at24_regmap_read_serial(at24, buf, off, count);
+		else
+			status = at24_regmap_read(at24, buf, off, count);
 		if (status < 0) {
 			mutex_unlock(&at24->lock);
 			return status;
-- 
2.14.1

[PATCH RFC 6/7] eeprom: at24: remove old read functions

[Heiner Kallweit]

Remove the old and now unused read functions.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/misc/eeprom/at24.c | 177 ---------------------------------------------
 1 file changed, 177 deletions(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 55b35007..8f2106d3 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -61,9 +61,6 @@ struct at24_client {
 
 struct at24_data {
 	struct at24_platform_data chip;
-	int use_smbus;
-
-	ssize_t (*read_func)(struct at24_data *, char *, unsigned int, size_t);
 
 	/*
 	 * Lock protects against activities from other Linux tasks,
@@ -219,37 +216,6 @@ static struct at24_client *at24_translate_offset(struct at24_data *at24,
 	return &at24->client[i];
 }
 
-static ssize_t at24_eeprom_read_smbus(struct at24_data *at24, char *buf,
-				      unsigned int offset, size_t count)
-{
-	unsigned long timeout, read_time;
-	struct i2c_client *client;
-	int status;
-
-	client = at24_translate_offset(at24, &offset)->client;
-
-	if (count > io_limit)
-		count = io_limit;
-
-	/* Smaller eeproms can work given some SMBus extension calls */
-	if (count > I2C_SMBUS_BLOCK_MAX)
-		count = I2C_SMBUS_BLOCK_MAX;
-
-	loop_until_timeout(timeout, read_time) {
-		status = i2c_smbus_read_i2c_block_data_or_emulated(client,
-								   offset,
-								   count, buf);
-
-		dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n",
-				count, offset, status, jiffies);
-
-		if (status == count)
-			return count;
-	}
-
-	return -ETIMEDOUT;
-}
-
 static ssize_t at24_regmap_read(struct at24_data *at24, char *buf,
 				unsigned int offset, size_t count)
 {
@@ -303,139 +269,6 @@ static ssize_t at24_regmap_read_serial(struct at24_data *at24, char *buf,
 	return -ETIMEDOUT;
 }
 
-static ssize_t at24_eeprom_read_i2c(struct at24_data *at24, char *buf,
-				    unsigned int offset, size_t count)
-{
-	unsigned long timeout, read_time;
-	struct i2c_client *client;
-	struct i2c_msg msg[2];
-	int status, i;
-	u8 msgbuf[2];
-
-	memset(msg, 0, sizeof(msg));
-	client = at24_translate_offset(at24, &offset)->client;
-
-	if (count > io_limit)
-		count = io_limit;
-
-	/*
-	 * When we have a better choice than SMBus calls, use a combined I2C
-	 * message. Write address; then read up to io_limit data bytes. Note
-	 * that read page rollover helps us here (unlike writes). msgbuf is
-	 * u8 and will cast to our needs.
-	 */
-	i = 0;
-	if (at24->chip.flags & AT24_FLAG_ADDR16)
-		msgbuf[i++] = offset >> 8;
-	msgbuf[i++] = offset;
-
-	msg[0].addr = client->addr;
-	msg[0].buf = msgbuf;
-	msg[0].len = i;
-
-	msg[1].addr = client->addr;
-	msg[1].flags = I2C_M_RD;
-	msg[1].buf = buf;
-	msg[1].len = count;
-
-	loop_until_timeout(timeout, read_time) {
-		status = i2c_transfer(client->adapter, msg, 2);
-		if (status == 2)
-			status = count;
-
-		dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n",
-				count, offset, status, jiffies);
-
-		if (status == count)
-			return count;
-	}
-
-	return -ETIMEDOUT;
-}
-
-static ssize_t at24_eeprom_read_serial(struct at24_data *at24, char *buf,
-				       unsigned int offset, size_t count)
-{
-	unsigned long timeout, read_time;
-	struct i2c_client *client;
-	struct i2c_msg msg[2];
-	u8 addrbuf[2];
-	int status;
-
-	client = at24_translate_offset(at24, &offset)->client;
-
-	memset(msg, 0, sizeof(msg));
-	msg[0].addr = client->addr;
-	msg[0].buf = addrbuf;
-
-	/*
-	 * The address pointer of the device is shared between the regular
-	 * EEPROM array and the serial number block. The dummy write (part of
-	 * the sequential read protocol) ensures the address pointer is reset
-	 * to the desired position.
-	 */
-	if (at24->chip.flags & AT24_FLAG_ADDR16) {
-		/*
-		 * For 16 bit address pointers, the word address must contain
-		 * a '10' sequence in bits 11 and 10 regardless of the
-		 * intended position of the address pointer.
-		 */
-		addrbuf[0] = 0x08;
-		addrbuf[1] = offset;
-		msg[0].len = 2;
-	} else {
-		/*
-		 * Otherwise the word address must begin with a '10' sequence,
-		 * regardless of the intended address.
-		 */
-		addrbuf[0] = 0x80 + offset;
-		msg[0].len = 1;
-	}
-
-	msg[1].addr = client->addr;
-	msg[1].flags = I2C_M_RD;
-	msg[1].buf = buf;
-	msg[1].len = count;
-
-	loop_until_timeout(timeout, read_time) {
-		status = i2c_transfer(client->adapter, msg, 2);
-		if (status == 2)
-			return count;
-	}
-
-	return -ETIMEDOUT;
-}
-
-static ssize_t at24_eeprom_read_mac(struct at24_data *at24, char *buf,
-				    unsigned int offset, size_t count)
-{
-	unsigned long timeout, read_time;
-	struct i2c_client *client;
-	struct i2c_msg msg[2];
-	u8 addrbuf[2];
-	int status;
-
-	client = at24_translate_offset(at24, &offset)->client;
-
-	memset(msg, 0, sizeof(msg));
-	msg[0].addr = client->addr;
-	msg[0].buf = addrbuf;
-	addrbuf[0] = 0x90 + offset;
-	msg[0].len = 1;
-	msg[1].addr = client->addr;
-	msg[1].flags = I2C_M_RD;
-	msg[1].buf = buf;
-	msg[1].len = count;
-
-	loop_until_timeout(timeout, read_time) {
-		status = i2c_transfer(client->adapter, msg, 2);
-		if (status == 2)
-			return count;
-	}
-
-	return -ETIMEDOUT;
-}
-
 /*
  * Note that if the hardware write-protect pin is pulled high, the whole
  * chip is normally write protected. But there are plenty of product
@@ -670,7 +503,6 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		return -ENOMEM;
 
 	mutex_init(&at24->lock);
-	at24->use_smbus = use_smbus;
 	at24->chip = chip;
 	at24->num_addresses = num_addresses;
 
@@ -685,15 +517,6 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		return -EINVAL;
 	}
 
-	if (chip.flags & AT24_FLAG_SERIAL) {
-		at24->read_func = at24_eeprom_read_serial;
-	} else if (chip.flags & AT24_FLAG_MAC) {
-		at24->read_func = at24_eeprom_read_mac;
-	} else {
-		at24->read_func = at24->use_smbus ? at24_eeprom_read_smbus
-						  : at24_eeprom_read_i2c;
-	}
-
 	writable = !(chip.flags & AT24_FLAG_READONLY);
 	if (writable) {
 		if (!use_smbus || use_smbus_write) {
-- 
2.14.1

[PATCH RFC 7/7] eeprom: at24: remove now unneeded smbus-related code

[Heiner Kallweit]

Remove remaining now unneeded code dealing with SMBUS details.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/misc/eeprom/at24.c | 52 ++++------------------------------------------
 1 file changed, 4 insertions(+), 48 deletions(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 8f2106d3..db8524b5 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -414,8 +414,6 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	struct at24_platform_data chip;
 	kernel_ulong_t magic = 0;
 	bool writable;
-	int use_smbus = 0;
-	int use_smbus_write = 0;
 	struct at24_data *at24;
 	int err;
 	unsigned i, num_addresses;
@@ -458,33 +456,10 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		dev_warn(&client->dev,
 			"page_size looks suspicious (no power of 2)!\n");
 
-	/* Use I2C operations unless we're stuck with SMBus extensions. */
-	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
-		if (chip.flags & AT24_FLAG_ADDR16)
-			return -EPFNOSUPPORT;
-
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 		if (i2c_check_functionality(client->adapter,
-				I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
-			use_smbus = I2C_SMBUS_I2C_BLOCK_DATA;
-		} else if (i2c_check_functionality(client->adapter,
-				I2C_FUNC_SMBUS_READ_WORD_DATA)) {
-			use_smbus = I2C_SMBUS_WORD_DATA;
-		} else if (i2c_check_functionality(client->adapter,
-				I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
-			use_smbus = I2C_SMBUS_BYTE_DATA;
-		} else {
-			return -EPFNOSUPPORT;
-		}
-
-		if (i2c_check_functionality(client->adapter,
-				I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) {
-			use_smbus_write = I2C_SMBUS_I2C_BLOCK_DATA;
-		} else if (i2c_check_functionality(client->adapter,
-				I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
-			use_smbus_write = I2C_SMBUS_BYTE_DATA;
+				I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
 			chip.page_size = 1;
-		}
-	}
 
 	if (chip.flags & AT24_FLAG_TAKE8ADDR)
 		num_addresses = 8;
@@ -518,21 +493,8 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	}
 
 	writable = !(chip.flags & AT24_FLAG_READONLY);
-	if (writable) {
-		if (!use_smbus || use_smbus_write) {
-
-			unsigned write_max = chip.page_size;
-
-			if (write_max > io_limit)
-				write_max = io_limit;
-			if (use_smbus && write_max > I2C_SMBUS_BLOCK_MAX)
-				write_max = I2C_SMBUS_BLOCK_MAX;
-			at24->write_max = write_max;
-		} else {
-			dev_warn(&client->dev,
-				"cannot write due to controller restrictions.");
-		}
-	}
+	if (writable)
+		at24->write_max = min_t(unsigned int, chip.page_size, io_limit);
 
 	/* use dummy devices for multiple-address chips */
 	for (i = 1; i < num_addresses; i++) {
@@ -588,12 +550,6 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	dev_info(&client->dev, "%u byte %s EEPROM, %s, %u bytes/write\n",
 		chip.byte_len, client->name,
 		writable ? "writable" : "read-only", at24->write_max);
-	if (use_smbus == I2C_SMBUS_WORD_DATA ||
-	    use_smbus == I2C_SMBUS_BYTE_DATA) {
-		dev_notice(&client->dev, "Falling back to %s reads, "
-			   "performance will suffer\n", use_smbus ==
-			   I2C_SMBUS_WORD_DATA ? "word" : "byte");
-	}
 
 	/* export data to kernel code */
 	if (chip.setup)
-- 
2.14.1