Re: [PATCH v5 2/4] usb: phy: samsung: Add host phy support tosamsung-phy driver

[Doug Anderson]

Vivek,

On Fri, Jan 11, 2013 at 4:40 AM, Vivek Gautam <gautamvivek1987@xxxxxxxxx> wrote:
>>> +#define HOST_CTRL0_REFCLKSEL_MASK              (0x3)
>>> +#define HOST_CTRL0_REFCLKSEL_XTAL              (0x0 << 19)
>>> +#define HOST_CTRL0_REFCLKSEL_EXTL              (0x1 << 19)
>>> +#define HOST_CTRL0_REFCLKSEL_CLKCORE           (0x2 << 19)
>>> +
>>> +#define HOST_CTRL0_FSEL_MASK                   (0x7 << 16)
>>> +#define HOST_CTRL0_FSEL(_x)                    ((_x) << 16)
>>> +#define HOST_CTRL0_FSEL_CLKSEL_50M             (0x7)
>>> +#define HOST_CTRL0_FSEL_CLKSEL_24M             (0x5)
>>> +#define HOST_CTRL0_FSEL_CLKSEL_20M             (0x4)
>>> +#define HOST_CTRL0_FSEL_CLKSEL_19200K          (0x3)
>>> +#define HOST_CTRL0_FSEL_CLKSEL_12M             (0x2)
>>> +#define HOST_CTRL0_FSEL_CLKSEL_10M             (0x1)
>>> +#define HOST_CTRL0_FSEL_CLKSEL_9600K           (0x0)
>>
>> Add the shifts to the #defines and remove HOST_CTRL0_FSEL(_x).  That
>> makes it match the older phy more closely.
>>
> Wouldn't it hamper the readability when shifts are used ??
> I mean if we have something like this -
>
> phyhost |= HOST_CTRL0_FSEL(phyclk)
>
> so, if we are using the shifts then
> phyhost |= (HOST_CTRL0_FSEL_CLKSEL_24M << HOST_CTRL0_FSEL_SHIFT)

I was actually suggesting modifying the #defines like this:

#define HOST_CTRL0_FSEL_SHIFT 16
#define HOST_CTRL0_FSEL_MASK                   (0x7 << HOST_CTRL0_FSEL_SHIFT)
#define HOST_CTRL0_FSEL_CLKSEL_50M             (0x7 << HOST_CTRL0_FSEL_SHIFT)
#define HOST_CTRL0_FSEL_CLKSEL_24M             (0x5 << HOST_CTRL0_FSEL_SHIFT)
#define HOST_CTRL0_FSEL_CLKSEL_20M             (0x4 << HOST_CTRL0_FSEL_SHIFT)
#define HOST_CTRL0_FSEL_CLKSEL_19200K          (0x3 << HOST_CTRL0_FSEL_SHIFT)
#define HOST_CTRL0_FSEL_CLKSEL_12M             (0x2 << HOST_CTRL0_FSEL_SHIFT)
#define HOST_CTRL0_FSEL_CLKSEL_10M             (0x1 << HOST_CTRL0_FSEL_SHIFT)
#define HOST_CTRL0_FSEL_CLKSEL_9600K           (0x0 << HOST_CTRL0_FSEL_SHIFT)

...then the code doesn't need to think about shifts, right?


>>>         if (IS_ERR(ref_clk)) {
>>>                 dev_err(sphy->dev, "Failed to get reference clock\n");
>>>                 return PTR_ERR(ref_clk);
>>>         }
>>>
>>> -       switch (clk_get_rate(ref_clk)) {
>>> -       case 12 * MHZ:
>>> -               refclk_freq = PHYCLK_CLKSEL_12M;
>>> -               break;
>>> -       case 24 * MHZ:
>>> -               refclk_freq = PHYCLK_CLKSEL_24M;
>>> -               break;
>>> -       case 48 * MHZ:
>>> -               refclk_freq = PHYCLK_CLKSEL_48M;
>>> -               break;
>>> -       default:
>>> -               if (sphy->cpu_type == TYPE_S3C64XX)
>>> -                       refclk_freq = PHYCLK_CLKSEL_48M;
>>> -               else
>>> +       if (sphy->cpu_type == TYPE_EXYNOS5250) {
>>> +               /* set clock frequency for PLL */
>>> +               switch (clk_get_rate(ref_clk)) {
>>> +               case 96 * 100000:
>>
>> nit: change to 9600 * KHZ to match; below too.
>>
> sure.
>
>>> +                       refclk_freq |= HOST_CTRL0_FSEL_CLKSEL_9600K;
>>
>> Why |= with 0?
>>
> kept this just to keep things look similar :-). will remove this line,

My comment was about keeping things similar.  Right now the 5250 code
has the |= and the non-5250 code doesn't.  I don't care which is
picked but the two sides of the "if" should be symmetric.

See parts of the patch below.

>>> +                       break;
>>> +               case 10 * MHZ:
>>> +                       refclk_freq |= HOST_CTRL0_FSEL_CLKSEL_10M;
>>> +                       break;
>>> +               case 12 * MHZ:
>>> +                       refclk_freq |= HOST_CTRL0_FSEL_CLKSEL_12M;
>>> +                       break;
>>> +               case 192 * 100000:
>>> +                       refclk_freq |= HOST_CTRL0_FSEL_CLKSEL_19200K;
>>> +                       break;
>>> +               case 20 * MHZ:
>>> +                       refclk_freq |= HOST_CTRL0_FSEL_CLKSEL_20M;
>>> +                       break;
>>> +               case 50 * MHZ:
>>> +                       refclk_freq |= HOST_CTRL0_FSEL_CLKSEL_50M;
>>> +                       break;
>>> +               case 24 * MHZ:
>>> +               default:
>>> +                       /* default reference clock */
>>> +                       refclk_freq |= HOST_CTRL0_FSEL_CLKSEL_24M;
>>> +                       break;
>>> +               }
>>> +       } else {
>>> +               switch (clk_get_rate(ref_clk)) {
>>> +               case 12 * MHZ:
>>> +                       refclk_freq = PHYCLK_CLKSEL_12M;
>>> +                       break;
>>> +               case 24 * MHZ:
>>>                         refclk_freq = PHYCLK_CLKSEL_24M;
>>> -               break;
>>> +                       break;
>>> +               case 48 * MHZ:
>>> +                       refclk_freq = PHYCLK_CLKSEL_48M;
>>> +                       break;
>>> +               default:
>>> +                       if (sphy->cpu_type == TYPE_S3C64XX)
>>> +                               refclk_freq = PHYCLK_CLKSEL_48M;
>>> +                       else
>>> +                               refclk_freq = PHYCLK_CLKSEL_24M;
>>> +                       break;
>>> +               }
>>>         }
>>>         clk_put(ref_clk);
>>>
>>>         return refclk_freq;
>>>  }

-Doug
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