[U-Boot] [PATCH 2/4] spi: ti_qspi: dra7xx: Add support to use 76.8MHz clock

[Jagan Teki]

On 27 July 2016 at 17:40, Vignesh R <vigneshr at ti.com> wrote:
>
>
> On Wednesday 27 July 2016 12:05 PM, Jagan Teki wrote:
>> On 25 July 2016 at 15:45, Vignesh R <vigneshr at ti.com> wrote:
>>> According to AM572x DM SPRS953A, QSPI bus speed can be 76.8MHz, update
>>> the driver to use the same.
>>>
>>> Signed-off-by: Vignesh R <vigneshr at ti.com>
>>> ---
>>>  drivers/spi/ti_qspi.c | 17 ++++++++++++-----
>>>  1 file changed, 12 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/spi/ti_qspi.c b/drivers/spi/ti_qspi.c
>>> index fa7ee229878a..bb72cb03ec24 100644
>>> --- a/drivers/spi/ti_qspi.c
>>> +++ b/drivers/spi/ti_qspi.c
>>> @@ -21,7 +21,8 @@ DECLARE_GLOBAL_DATA_PTR;
>>>
>>>  /* ti qpsi register bit masks */
>>>  #define QSPI_TIMEOUT                    2000000
>>> -#define QSPI_FCLK                       192000000
>>> +#define QSPI_FCLK                      192000000
>>> +#define QSPI_DRA7XX_FCLK                76800000
>>>  /* clock control */
>>>  #define QSPI_CLK_EN                     BIT(31)
>>>  #define QSPI_CLK_DIV_MAX                0xffff
>>> @@ -101,6 +102,7 @@ struct ti_qspi_priv {
>>>  #endif
>>>         struct ti_qspi_regs *base;
>>>         void *ctrl_mod_mmap;
>>> +       ulong fclk;
>>>         unsigned int mode;
>>>         u32 cmd;
>>>         u32 dc;
>>> @@ -113,7 +115,7 @@ static void ti_spi_set_speed(struct ti_qspi_priv *priv, uint hz)
>>>         if (!hz)
>>>                 clk_div = 0;
>>>         else
>>> -               clk_div = (QSPI_FCLK / hz) - 1;
>>> +               clk_div = (priv->fclk / hz) - 1;
>>
>> Then how this relate to max_hz (priv->max_hz), look like it is not
>> using anywhere.
>
> I think priv-max_hz defines the max frequency QSPI IP can support (flash
> node can always be configured to run at higher or lower frequency which
> is specified by spi-max-frequency in flash subnode). What's missing is a
> check to see if frequency requested in set_speed() is not greater than
> priv->max_hz. I will implement that in another series.

Reviewed-by: Jagan Teki <jteki at openedev.com>

-- 
Jagan.