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SubjectRe: [RFC PATCH] i2c: stub: Add support for SMBus block commands
On Mon, 07 Jul 2014 06:32:02 -0700, Guenter Roeck wrote:
> On 07/07/2014 01:27 AM, Jean Delvare wrote:
> > On Sun, 6 Jul 2014 20:55:12 -0700, Guenter Roeck wrote:
> >> chip->words[command] &= 0xff00;
> >> chip->words[command] |= data->byte;
> >> dev_dbg(&adap->dev,
> >> "smbus byte data - addr 0x%02x, wrote 0x%02x at 0x%02x.\n",
> >> addr, data->byte, command);
> >> } else {
> >> - data->byte = chip->words[command] & 0xff;
> >> + if (b)
> >> + data->byte = b->len;
> >> + else
> >> + data->byte = chip->words[command] & 0xff;
> >
> > You could avoid this conditional (and the same below in case
> > I2C_SMBUS_WORD_DATA) by writing to chip->words at the same time you
> > write to b->block. Block transfers being rare and reads occurring more
> > frequently than writes, I think the performance benefit is clear.
>
> Makes sense, I'll do that. Great idea.
>
> Question is if I should cover attempts to write a byte or word into block data.
> I don't think it is worth the effort, as drivers won't usually do that.
> My take is that we could add it later if really needed.
> What do you think ?

I agree. The i2c-stub driver can't possibly cover every use case
anyway, so let's keep it simple and only emulate behaviors we need for
real.

--
Jean Delvare
SUSE L3 Support


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