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Commit 14674e70119ea01549ce593d8901a797f8a90f74

Authored by Mark Brown
Committed by Jean Delvare
1 parent 838bfa6049
Exists in smarc-l5.0.0_1.0.0-ga and in 5 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga

i2c: Split I2C_M_NOSTART support out of I2C_FUNC_PROTOCOL_MANGLING 

Since there are uses for I2C_M_NOSTART which are much more sensible and
standard than most of the protocol mangling functionality (the main one
being gather writes to devices where something like a register address
needs to be inserted before a block of data) create a new I2C_FUNC_NOSTART
for this feature and update all the users to use it.

Also strengthen the disrecommendation of the protocol mangling while we're
at it.

In the case of regmap-i2c we remove the requirement for mangling as
I2C_M_NOSTART is the only mangling feature which is being used.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Showing 9 changed files with 25 additions and 10 deletions Side-by-side Diff

Documentation/i2c/functionality
Diff comments   View file @ 14674e7
... ... @@ -18,9 +18,9 @@
18 18 adapters typically can not do these)
19 19 I2C_FUNC_10BIT_ADDR Handles the 10-bit address extensions
20 20 I2C_FUNC_PROTOCOL_MANGLING Knows about the I2C_M_IGNORE_NAK,
21   - I2C_M_REV_DIR_ADDR, I2C_M_NOSTART and
22   - I2C_M_NO_RD_ACK flags (which modify the
23   - I2C protocol!)
  21 + I2C_M_REV_DIR_ADDR and I2C_M_NO_RD_ACK
  22 + flags (which modify the I2C protocol!)
  23 + I2C_FUNC_NOSTART Can skip repeated start sequence
24 24 I2C_FUNC_SMBUS_QUICK Handles the SMBus write_quick command
25 25 I2C_FUNC_SMBUS_READ_BYTE Handles the SMBus read_byte command
26 26 I2C_FUNC_SMBUS_WRITE_BYTE Handles the SMBus write_byte command
... ... @@ -49,6 +49,9 @@
49 49 I2C_FUNC_SMBUS_EMUL Handles all SMBus commands than can be
50 50 emulated by a real I2C adapter (using
51 51 the transparent emulation layer)
  52 +
  53 +In kernel versions prior to 3.5 I2C_FUNC_NOSTART was implemented as
  54 +part of I2C_FUNC_PROTOCOL_MANGLING.
52 55  
53 56  
54 57 ADAPTER IMPLEMENTATION
Documentation/i2c/i2c-protocol
Diff comments   View file @ 14674e7
... ... @@ -49,7 +49,9 @@
49 49 Modified transactions
50 50 =====================
51 51  
52   -We have found some I2C devices that needs the following modifications:
  52 +The following modifications to the I2C protocol can also be generated,
  53 +with the exception of I2C_M_NOSTART these are usually only needed to
  54 +work around device issues:
53 55  
54 56 Flag I2C_M_NOSTART:
55 57 In a combined transaction, no 'S Addr Wr/Rd [A]' is generated at some
... ... @@ -59,6 +61,11 @@
59 61 If you set the I2C_M_NOSTART variable for the first partial message,
60 62 we do not generate Addr, but we do generate the startbit S. This will
61 63 probably confuse all other clients on your bus, so don't try this.
  64 +
  65 + This is often used to gather transmits from multiple data buffers in
  66 + system memory into something that appears as a single transfer to the
  67 + I2C device but may also be used between direction changes by some
  68 + rare devices.
62 69  
63 70 Flags I2C_M_REV_DIR_ADDR
64 71 This toggles the Rd/Wr flag. That is, if you want to do a write, but
drivers/base/regmap/regmap-i2c.c
Diff comments   View file @ 14674e7
... ... @@ -42,7 +42,7 @@
42 42 /* If the I2C controller can't do a gather tell the core, it
43 43 * will substitute in a linear write for us.
44 44 */
45   - if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_PROTOCOL_MANGLING))
  45 + if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_NOSTART))
46 46 return -ENOTSUPP;
47 47  
48 48 xfer[0].addr = i2c->addr;
drivers/i2c/algos/i2c-algo-bit.c
Diff comments   View file @ 14674e7
... ... @@ -608,7 +608,7 @@
608 608  
609 609 static u32 bit_func(struct i2c_adapter *adap)
610 610 {
611   - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
  611 + return I2C_FUNC_I2C | I2C_FUNC_NOSTART | I2C_FUNC_SMBUS_EMUL |
612 612 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
613 613 I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
614 614 I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
drivers/i2c/busses/i2c-nuc900.c
Diff comments   View file @ 14674e7
... ... @@ -502,7 +502,8 @@
502 502 /* declare our i2c functionality */
503 503 static u32 nuc900_i2c_func(struct i2c_adapter *adap)
504 504 {
505   - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
  505 + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART |
  506 + I2C_FUNC_PROTOCOL_MANGLING;
506 507 }
507 508  
508 509 /* i2c bus registration info */
drivers/i2c/busses/i2c-s3c2410.c
Diff comments   View file @ 14674e7
... ... @@ -626,7 +626,8 @@
626 626 /* declare our i2c functionality */
627 627 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
628 628 {
629   - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
  629 + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART |
  630 + I2C_FUNC_PROTOCOL_MANGLING;
630 631 }
631 632  
632 633 /* i2c bus registration info */
drivers/input/joystick/as5011.c
Diff comments   View file @ 14674e7
... ... @@ -231,6 +231,7 @@
231 231 }
232 232  
233 233 if (!i2c_check_functionality(client->adapter,
  234 + I2C_FUNC_NOSTART |
234 235 I2C_FUNC_PROTOCOL_MANGLING)) {
235 236 dev_err(&client->dev,
236 237 "need i2c bus that supports protocol mangling\n");
drivers/video/matrox/matroxfb_maven.c
Diff comments   View file @ 14674e7
... ... @@ -1243,6 +1243,7 @@
1243 1243  
1244 1244 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_WORD_DATA |
1245 1245 I2C_FUNC_SMBUS_BYTE_DATA |
  1246 + I2C_FUNC_NOSTART |
1246 1247 I2C_FUNC_PROTOCOL_MANGLING))
1247 1248 goto ERROR0;
1248 1249 if (!(data = kzalloc(sizeof(*data), GFP_KERNEL))) {
... ... @@ -541,7 +541,7 @@
541 541 __u16 flags;
542 542 #define I2C_M_TEN 0x0010 /* this is a ten bit chip address */
543 543 #define I2C_M_RD 0x0001 /* read data, from slave to master */
544   -#define I2C_M_NOSTART 0x4000 /* if I2C_FUNC_PROTOCOL_MANGLING */
  544 +#define I2C_M_NOSTART 0x4000 /* if I2C_FUNC_NOSTART */
545 545 #define I2C_M_REV_DIR_ADDR 0x2000 /* if I2C_FUNC_PROTOCOL_MANGLING */
546 546 #define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */
547 547 #define I2C_M_NO_RD_ACK 0x0800 /* if I2C_FUNC_PROTOCOL_MANGLING */
548 548  
... ... @@ -554,8 +554,9 @@
554 554  
555 555 #define I2C_FUNC_I2C 0x00000001
556 556 #define I2C_FUNC_10BIT_ADDR 0x00000002
557   -#define I2C_FUNC_PROTOCOL_MANGLING 0x00000004 /* I2C_M_NOSTART etc. */
  557 +#define I2C_FUNC_PROTOCOL_MANGLING 0x00000004 /* I2C_M_IGNORE_NAK etc. */
558 558 #define I2C_FUNC_SMBUS_PEC 0x00000008
  559 +#define I2C_FUNC_NOSTART 0x00000010 /* I2C_M_NOSTART */
559 560 #define I2C_FUNC_SMBUS_BLOCK_PROC_CALL 0x00008000 /* SMBus 2.0 */
560 561 #define I2C_FUNC_SMBUS_QUICK 0x00010000
561 562 #define I2C_FUNC_SMBUS_READ_BYTE 0x00020000