[PATCH v3 1/3] Documentation/i2c: whitespace cleanup

[PATCH v3 1/3] Documentation/i2c: whitespace cleanup

[Sam Hansen]

This strips trailing whitespace in Documentation/i2c/dev-interface.

Signed-off-by: Sam Hansen <hansens@google.com>
---
No changes from v2.

 Documentation/i2c/dev-interface | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/Documentation/i2c/dev-interface b/Documentation/i2c/dev-interface
index d04e6e4964ee..c8737d502791 100644
--- a/Documentation/i2c/dev-interface
+++ b/Documentation/i2c/dev-interface
@@ -9,8 +9,8 @@ i2c adapters present on your system at a given time. i2cdetect is part of
 the i2c-tools package.
 
 I2C device files are character device files with major device number 89
-and a minor device number corresponding to the number assigned as 
-explained above. They should be called "i2c-%d" (i2c-0, i2c-1, ..., 
+and a minor device number corresponding to the number assigned as
+explained above. They should be called "i2c-%d" (i2c-0, i2c-1, ...,
 i2c-10, ...). All 256 minor device numbers are reserved for i2c.
 
 
@@ -38,7 +38,7 @@ Next thing, open the device file, as follows:
   int file;
   int adapter_nr = 2; /* probably dynamically determined */
   char filename[20];
-  
+
   snprintf(filename, 19, "/dev/i2c-%d", adapter_nr);
   file = open(filename, O_RDWR);
   if (file < 0) {
@@ -72,7 +72,7 @@ the device supports them. Both are illustrated below.
     /* res contains the read word */
   }
 
-  /* Using I2C Write, equivalent of 
+  /* Using I2C Write, equivalent of
      i2c_smbus_write_word_data(file, reg, 0x6543) */
   buf[0] = reg;
   buf[1] = 0x43;
@@ -147,7 +147,7 @@ You can do plain i2c transactions by using read(2) and write(2) calls.
 You do not need to pass the address byte; instead, set it through
 ioctl I2C_SLAVE before you try to access the device.
 
-You can do SMBus level transactions (see documentation file smbus-protocol 
+You can do SMBus level transactions (see documentation file smbus-protocol
 for details) through the following functions:
   __s32 i2c_smbus_write_quick(int file, __u8 value);
   __s32 i2c_smbus_read_byte(int file);
@@ -158,7 +158,7 @@ for details) through the following functions:
   __s32 i2c_smbus_write_word_data(int file, __u8 command, __u16 value);
   __s32 i2c_smbus_process_call(int file, __u8 command, __u16 value);
   __s32 i2c_smbus_read_block_data(int file, __u8 command, __u8 *values);
-  __s32 i2c_smbus_write_block_data(int file, __u8 command, __u8 length, 
+  __s32 i2c_smbus_write_block_data(int file, __u8 command, __u8 length,
                                    __u8 *values);
 All these transactions return -1 on failure; you can read errno to see
 what happened. The 'write' transactions return 0 on success; the
-- 
2.17.0.484.g0c8726318c-goog

[PATCH v3 2/3] Documentation/i2c: sync docs with current state of i2c-tools

[Sam Hansen]

Currently, Documentation/i2c/dev-interface describes the use of
i2c_smbus_* helper routines as static inlined functions provided by
linux/i2c-dev.h.  Work has been done to refactor the linux/i2c-dev.h file
in the i2c-tools project out into its own library.  As a result, these
docs have become stale.

This patch corrects the discrepancy and directs the reader to the
i2c-tools project for more information.

Signed-off-by: Sam Hansen <hansens@google.com>
---
No changes from v2.

 Documentation/i2c/dev-interface | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/Documentation/i2c/dev-interface b/Documentation/i2c/dev-interface
index c8737d502791..f92ee1f59914 100644
--- a/Documentation/i2c/dev-interface
+++ b/Documentation/i2c/dev-interface
@@ -23,11 +23,6 @@ First, you need to include these two headers:
   #include <linux/i2c-dev.h>
   #include <i2c/smbus.h>
 
-(Please note that there are two files named "i2c-dev.h" out there. One is
-distributed with the Linux kernel and the other one is included in the
-source tree of i2c-tools. They used to be different in content but since 2012
-they're identical. You should use "linux/i2c-dev.h").
-
 Now, you have to decide which adapter you want to access. You should
 inspect /sys/class/i2c-dev/ or run "i2cdetect -l" to decide this.
 Adapter numbers are assigned somewhat dynamically, so you can not
@@ -140,8 +135,8 @@ ioctl(file, I2C_RDWR, struct i2c_rdwr_ioctl_data *msgset)
   set in each message, overriding the values set with the above ioctl's.
 
 ioctl(file, I2C_SMBUS, struct i2c_smbus_ioctl_data *args)
-  Not meant to be called  directly; instead, use the access functions
-  below.
+  If possible, use the provided i2c_smbus_* methods described below instead
+  of issuing direct ioctls.
 
 You can do plain i2c transactions by using read(2) and write(2) calls.
 You do not need to pass the address byte; instead, set it through
@@ -166,10 +161,9 @@ what happened. The 'write' transactions return 0 on success; the
 returns the number of values read. The block buffers need not be longer
 than 32 bytes.
 
-The above functions are all inline functions, that resolve to calls to
-the i2c_smbus_access function, that on its turn calls a specific ioctl
-with the data in a specific format. Read the source code if you
-want to know what happens behind the screens.
+The above functions are made available by linking against the libi2c library,
+which is provided by the i2c-tools project.  See:
+https://git.kernel.org/pub/scm/utils/i2c-tools/i2c-tools.git/.
 
 
 Implementation details
-- 
2.17.0.484.g0c8726318c-goog

[PATCH v3 3/3] Documentation/i2c: adopt kernel commenting style in examples

[Sam Hansen]

The example I2C code is rewritten to adopt the preferred kernel block
commenting style.

Signed-off-by: Sam Hansen <hansens@google.com>
---
Changes from v2:
  1. only the block comment is updated.
  2. one-line comments are reverted to prior form.

 Documentation/i2c/dev-interface | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Documentation/i2c/dev-interface b/Documentation/i2c/dev-interface
index f92ee1f59914..fbed645ccd75 100644
--- a/Documentation/i2c/dev-interface
+++ b/Documentation/i2c/dev-interface
@@ -67,8 +67,10 @@ the device supports them. Both are illustrated below.
     /* res contains the read word */
   }
 
-  /* Using I2C Write, equivalent of
-     i2c_smbus_write_word_data(file, reg, 0x6543) */
+  /*
+   * Using I2C Write, equivalent of
+   * i2c_smbus_write_word_data(file, reg, 0x6543)
+   */
   buf[0] = reg;
   buf[1] = 0x43;
   buf[2] = 0x65;
-- 
2.17.0.484.g0c8726318c-goog

Re: [PATCH v3 1/3] Documentation/i2c: whitespace cleanup

[Wolfram Sang]

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On Fri, Apr 13, 2018 at 10:42:55AM -0700, Sam Hansen wrote:
> This strips trailing whitespace in Documentation/i2c/dev-interface.
> 
> Signed-off-by: Sam Hansen <hansens@google.com>

Applied to for-current, thanks!


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Re: [PATCH v3 2/3] Documentation/i2c: sync docs with current state of i2c-tools

[Wolfram Sang]

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On Fri, Apr 13, 2018 at 10:42:56AM -0700, Sam Hansen wrote:
> Currently, Documentation/i2c/dev-interface describes the use of
> i2c_smbus_* helper routines as static inlined functions provided by
> linux/i2c-dev.h.  Work has been done to refactor the linux/i2c-dev.h file
> in the i2c-tools project out into its own library.  As a result, these
> docs have become stale.
> 
> This patch corrects the discrepancy and directs the reader to the
> i2c-tools project for more information.
> 
> Signed-off-by: Sam Hansen <hansens@google.com>

Applied to for-current, thanks!


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Re: [PATCH v3 3/3] Documentation/i2c: adopt kernel commenting style in examples

[Wolfram Sang]

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On Fri, Apr 13, 2018 at 10:42:57AM -0700, Sam Hansen wrote:
> The example I2C code is rewritten to adopt the preferred kernel block
> commenting style.
> 
> Signed-off-by: Sam Hansen <hansens@google.com>

Applied to for-current, thanks!


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Re: [PATCH v3 2/3] Documentation/i2c: sync docs with current state of i2c-tools

[Wolfram Sang]

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> +The above functions are made available by linking against the libi2c library,
> +which is provided by the i2c-tools project.  See:
> +https://git.kernel.org/pub/scm/utils/i2c-tools/i2c-tools.git/.

In the beginning, we say that '#include <i2c/smbus.h>' is needed.
Shouldn't we mention i2c-tools there already and in what case it is
needed (only for SMBus)? I'd think so.

Sam, would you be open to do this as an incremental patch?


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Re: [PATCH v3 2/3] Documentation/i2c: sync docs with current state of i2c-tools

[Sam Hansen]

On Wed, Apr 18, 2018 at 1:21 AM, Wolfram Sang <wsa@the-dreams.de> wrote:
>
>> +The above functions are made available by linking against the libi2c library,
>> +which is provided by the i2c-tools project.  See:
>> +https://git.kernel.org/pub/scm/utils/i2c-tools/i2c-tools.git/.
>
> In the beginning, we say that '#include <i2c/smbus.h>' is needed.
> Shouldn't we mention i2c-tools there already and in what case it is
> needed (only for SMBus)? I'd think so.
>
> Sam, would you be open to do this as an incremental patch?

Yup, I'll send an incremental patch touching this up, thanks.

>