Merge branch 'i2c/for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c updates from Wolfram Sang:
 "For 3.19, the I2C subsystem has to offer special candy this time.
  Right in time for Christmas :)

   - I2C slave framework: finally, a generic mechanism for Linux being
     an I2C slave (if the bus driver supports that).  Docs are still
     missing but will come later this cycle, the code is good enough to
     go.
   - I2C muxes represent their topology in sysfs much more detailed.
     This will help users to navigate around much easier.
   - irq population of i2c clients is now done at probe time, not device
     creation time, to have better support for deferred probing.
   - new drivers for Imagination SCB, Amlogic Meson
   - DMA support added for Freescale IMX, Renesas SHMobile
   - slightly bigger driver updates to OMAP, i801, AT91, and rk3x
     (mostly quirk handling, timing updates, and using better kernel
     interfaces)
   - eeprom driver can now write with byte-access (very slow, but OK to
     have)
   - and the bunch of smaller fixes, cleanups, ID updates..."

* 'i2c/for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (56 commits)
  i2c: sh_mobile: remove unneeded DMA mask
  i2c: rcar: add slave support
  i2c: slave-eeprom: add eeprom simulator driver
  i2c: core changes for slave support
  MAINTAINERS: add I2C dt bindings also to I2C realm
  i2c: designware: Fix falling time bindings doc
  i2c: davinci: switch to use platform_get_irq
  Documentation: i2c: Use PM ops instead of legacy suspend/resume
  i2c: sh_mobile: optimize irq entry
  i2c: pxa: add support for SCCB devices
  omap: i2c: don't check bus state IP rev3.3 and earlier
  i2c: s3c2410: Handle i2c sys_cfg register in i2c driver
  i2c: rk3x: add Kconfig dependency on COMMON_CLK
  i2c: omap: add notes related to i2c multimaster mode
  i2c: omap: don't reset controller if Arbitration Lost detected
  i2c: omap: implement workaround for handling invalid BB-bit values
  i2c: omap: cleanup register definitions
  i2c: rk3x: handle dynamic clock rate changes correctly
  i2c: at91: enable probe deferring on dma channel request
  i2c: at91: remove legacy DMA support
  ...

1 files changed, 29 insertions, 6 deletions

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index d87f77f790d6..2d3db81be099 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -56,6 +56,7 @@ struct at24_data {
         struct at24_platform_data chip;
         struct memory_accessor macc;
         int use_smbus;
+        int use_smbus_write;
 
         /*
          * Lock protects against activities from other Linux tasks,
@@ -324,7 +325,7 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf,
 {
         struct i2c_client *client;
         struct i2c_msg msg;
-        ssize_t status;
+        ssize_t status = 0;
         unsigned long timeout, write_time;
         unsigned next_page;
 
@@ -365,9 +366,18 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf,
         timeout = jiffies + msecs_to_jiffies(write_timeout);
         do {
                 write_time = jiffies;
-                if (at24->use_smbus) {
-                        status = i2c_smbus_write_i2c_block_data(client,
-                                        offset, count, buf);
+                if (at24->use_smbus_write) {
+                        switch (at24->use_smbus_write) {
+                        case I2C_SMBUS_I2C_BLOCK_DATA:
+                                status = i2c_smbus_write_i2c_block_data(client,
+                                                offset, count, buf);
+                                break;
+                        case I2C_SMBUS_BYTE_DATA:
+                                status = i2c_smbus_write_byte_data(client,
+                                                offset, buf[0]);
+                                break;
+                        }
+
                         if (status == 0)
                                 status = count;
                 } else {
@@ -487,6 +497,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
         struct at24_platform_data chip;
         bool writable;
         int use_smbus = 0;
+        int use_smbus_write = 0;
         struct at24_data *at24;
         int err;
         unsigned i, num_addresses;
@@ -546,6 +557,18 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
                 }
         }
 
+        /* Use I2C operations unless we're stuck with SMBus extensions. */
+        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+                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;
+                        chip.page_size = 1;
+                }
+        }
+
         if (chip.flags & AT24_FLAG_TAKE8ADDR)
                 num_addresses = 8;
         else
@@ -559,6 +582,7 @@ 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;
 
@@ -576,8 +600,7 @@ 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 || i2c_check_functionality(client->adapter,
-                                I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) {
+                if (!use_smbus || use_smbus_write) {
 
                         unsigned write_max = chip.page_size;