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

[Marek Vasut]

On 5/30/19 11:07 AM, Ley Foon Tan wrote:
> On Thu, May 30, 2019 at 4:59 PM Marek Vasut <marex at denx.de> wrote:
>>
>> On 5/30/19 10:43 AM, Ley Foon Tan wrote:
>>> Get clock rate from clock DM if CONFIG_CLK is enabled.
>>> Otherwise, uses IC_CLK define.
>>>
>>> Signed-off-by: Ley Foon Tan <ley.foon.tan at intel.com>
>>> ---
>>>  drivers/i2c/designware_i2c.c | 54 +++++++++++++++++++++++++++++-------
>>>  1 file changed, 44 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/i2c/designware_i2c.c b/drivers/i2c/designware_i2c.c
>>> index 9ccc2411a6..a1ed30650c 100644
>>> --- a/drivers/i2c/designware_i2c.c
>>> +++ b/drivers/i2c/designware_i2c.c
>>> @@ -4,6 +4,7 @@
>>>   * Vipin Kumar, ST Micoelectronics, vipin.kumar at st.com.
>>>   */
>>>
>>> +#include <clk.h>
>>>  #include <common.h>
>>>  #include <dm.h>
>>>  #include <i2c.h>
>>> @@ -35,6 +36,9 @@ struct dw_i2c {
>>>       struct i2c_regs *regs;
>>>       struct dw_scl_sda_cfg *scl_sda_cfg;
>>>       struct reset_ctl_bulk resets;
>>> +#if CONFIG_IS_ENABLED(CLK)
>>> +     struct clk clk;
>>> +#endif
>>>  };
>>>
>>>  #ifdef CONFIG_SYS_I2C_DW_ENABLE_STATUS_UNSUPPORTED
>>> @@ -78,7 +82,7 @@ static int dw_i2c_enable(struct i2c_regs *i2c_base, bool enable)
>>>   */
>>>  static unsigned int __dw_i2c_set_bus_speed(struct i2c_regs *i2c_base,
>>>                                          struct dw_scl_sda_cfg *scl_sda_cfg,
>>> -                                        unsigned int speed)
>>> +                                        unsigned int speed, u32 bus_mhz)
>>
>> unsigned int bus_mhz , it's not a fixed-width register content, but just
>> some random unsigned integer.
> You mean change u32 to unsigned int?

Yes

>> [...]
>>
>>> @@ -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().

> Will change it.
> 
> Thanks.
> 
> Regards
> Ley Foon
> 


-- 
Best regards,
Marek Vasut