Hi Uwe, On 28 September 2012 12:57, Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> wrote: > On Fri, Sep 28, 2012 at 09:11:34AM +0530, viresh kumar wrote: >> This was done, because few platforms may not have configuration bits to read >> status of sda line.. For them skip_sda_polling was required. >> >> Whereas, others would need this to see if we can return early. > What is the upside of returning early? I'd say, just don't do it. Save time. Why give additional clocks when you don't actually need them? Can use likely/unlikely to make it more efficient for 9 clock pulse scenario though. >> >> + * @put_gpio: called after recover_bus() to get padmux configured for scl line >> >> + * as scl. Only required if is_gpio_recovery == true. >> >> + * @scl_gpio: gpio number of the scl line. Only required if is_gpio_recovery == >> >> + * true. >> >> + * @sda_gpio: gpio number of the sda line. Only required if is_gpio_recovery == >> >> + * true and skip_sda_polling == false. >> >> + * @scl_gpio_flags: flag for gpio_request_one of scl_gpio. 0 implies >> >> + * GPIOF_OUT_INIT_LOW. >> > IMHO you should not make this configurable but use >> > >> > GPIOF_OUT_INIT_HIGH | GPIOF_OPEN_DRAIN >> >> Discussed here: >> http://www.spinics.net/lists/linux-i2c/msg07325.html > Why do you default to GPIOF_OUT_INIT_LOW? The idle state of scl is high. > Using low here introduces an additional clk pulse. We aren't giving any clock pulses to scl line. Are you talking about sda? -- viresh -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
