[U-Boot] [PATCH] i2c: designware: Get clock rate from clock DM

[Ley Foon Tan]

On Mon, Jun 10, 2019 at 8:07 PM Marek Vasut <marex at denx.de> wrote:
>
> On 6/10/19 8:07 AM, Ley Foon Tan wrote:
> [...]
>
> >>>> [...]
> >>>>
> >>>>> @@ -523,8 +527,20 @@ static int designware_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
> >>>>>  static int designware_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
> >>>>>  {
> >>>>>       struct dw_i2c *i2c = dev_get_priv(bus);
> >>>>> +     ulong rate;
> >>>>> +
> >>>>> +#if CONFIG_IS_ENABLED(CLK)
> >>>>> +     rate = clk_get_rate(&i2c->clk);
> >>>>
> >>>> Do we need to re-read the bus frequency for each transfer ?
> >>>> I would expect set_bus_speed callback to set the frequencies once and
> >>>> then keep them that way until it's called again.
> >>> Yes, we can get clock rate when request clock in _probe(). Then keep a
> >>> copy for future use.
> >>
> >> Not in .probe() , in set_bus_speed().
> > My patch is doing it in designware_i2c_set_bus_speed() already.  We
> > can't get clock rate in __dw_i2c_set_bus_speed(), because this
> > function doesn't have struct udevice.
>
> include/i2c.h struct dm_i2c_ops {} :
>
> 388         /**
> 389          * set_bus_speed() - set the speed of a bus (optional)
> 390          *
> 391          * The bus speed value will be updated by the uclass if this
> function
> 392          * does not return an error. This method is optional - if it
> is not
> 393          * provided then the driver can read the speed from
> 394          * dev_get_uclass_priv(bus)->speed_hz
> 395          *
> 396          * @bus:        Bus to adjust
> 397          * @speed:      Requested speed in Hz
> 398          * @return 0 if OK, -EINVAL for invalid values
> 399          */
> 400         int (*set_bus_speed)(struct udevice *bus, unsigned int speed);
>
> There's struct udevice right there ^

I'm confused now.

.set_bus_speed  = designware_i2c_set_bus_speed and my patch is doing
get clock rate in .set_bus_speed callback already.

static const struct dm_i2c_ops designware_i2c_ops = {
        .xfer           = designware_i2c_xfer,
        .probe_chip     = designware_i2c_probe_chip,
        .set_bus_speed  = designware_i2c_set_bus_speed,
};

Regards
Ley Foon