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

[Marek Vasut]

On 6/11/19 3:05 AM, Ley Foon Tan wrote:
> 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,
> };

Uh, clearly I was confused as well, sorry.

Acked-by: Marek Vasut <marex at denx.de>

-- 
Best regards,
Marek Vasut