[RFC] commands: i2c_write: enable raw write to address

Antony Pavlov antonynpavlov at gmail.com
Fri Feb 9 03:22:24 PST 2018


On Fri, 9 Feb 2018 09:36:36 +0100
Sascha Hauer <s.hauer at pengutronix.de> wrote:

> Hi Antony,
> 
> On Thu, Feb 08, 2018 at 10:48:56AM +0300, Antony Pavlov wrote:
> > Sometimes for communication with a simple I2C devices
> > (e.g. PCF8574 or TM1650) it's necessary to send only
> > one data byte into the I2C device.
> > Current i2c_write command makes this impossible because
> > you can't just pass 'device address' and 'register number'
> > (or 'device address' and 'one data byte') to the command.
> > You always have to pass all three parameters:
> > 'device address', 'register number' and 'data'.
> > 
> > This commit fixes the problem.
> > 
> > Sample usage:
> > 
> >   barebox at barebox sandbox:/ i2c_write -a 0x24 0x01
> > 
> > Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
> > ---
> >  commands/i2c.c | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> Looks good to me.
> 
> I applied this one despite the [RFC] tag. If for some reason you want to
> resend this, feel free to do so, but otherwise consider this applied.

Thanks!

The patch is short, it's understandable and it fixes the problem.
I prefere to apply this patch as is.

I see some inconsistency in drivers/i2c/i2c.c.
We have i2c_master_send() and i2c_write_reg() functions.
These functions are intended to make similar work but they are
written in very different style. I suppose that we can rewrite
i2c_master_send() (e.g. drop FIXME) and make i2c_write_reg()
work on top of i2c_master_send(). Any comments?

-- 
Best regards,
  Antony Pavlov



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