[U-Boot] [PATCH v3 1/2] i2c: sh_i2c: bugfix: i2c probe command does not work

[Tom Rini]

On Mon, Apr 14, 2014 at 05:13:57PM +0900, Tetsuyuki Kobayashi wrote:
> This is regression of commit 2035d77d i2c: sh_i2c: Update to new CONFIG_SYS_I2C framework
> 
> Before commit 2035d77d, i2c probe command works properly on kzm9g board.
> 
> KZM-A9-GT# i2c probe
> Valid chip addresses: 0C 12 1D 32 39 3D 40 60
> 
> After commit 2035d77d, i2c probe command does not work.
> 
> KZM-A9-GT# i2c probe
> Valid chip addresses: 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F 40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F 60 61 62 63 64 65 66 67 68 69 6A 6B 6C 6D 6E 6F 70 71 72 73 74 75 76 77 78 79 7A 7B 7C 7D 7E 7F
> 
> sh_i2c_probe() calls sh_i2c_read(), but read length is 0. So acutally it does not read device at all. This patch prepares dummy buffer and read data into it.
> 
> Signed-off-by: Tetsuyuki Kobayashi <koba at kmckk.co.jp>
> ---
> Changes for v2:
>   - correct typo in commit message.
> 
> Changes for v3:
>   - prepare dummy data buffer and use it to avoid NULL access.
> 
>  drivers/i2c/sh_i2c.c |    4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/sh_i2c.c b/drivers/i2c/sh_i2c.c
> index cc19100..e7e9692 100644
> --- a/drivers/i2c/sh_i2c.c
> +++ b/drivers/i2c/sh_i2c.c
> @@ -269,7 +269,9 @@ static int sh_i2c_write(struct i2c_adapter *adap, uint8_t chip, uint addr,
>  static int
>  sh_i2c_probe(struct i2c_adapter *adap, u8 dev)
>  {
> -	return sh_i2c_read(adap, dev, 0, 0, NULL, 0);
> +	u8 dummy[1];
> +
> +	return sh_i2c_read(adap, dev, 0, 0, dummy, sizeof dummy);
>  }
>  
>  static unsigned int sh_i2c_set_bus_speed(struct i2c_adapter *adap,

I will take this patch as-is, but please use sizeof(foo) rather than
sizeof foo.  It's valid but uncommon syntax for the project, thanks!

-- 
Tom
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