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Message-ID: <CAD=FV=XhMbWjCR5r=R3+zE1524NuUUvFDf2HZuCrXPmsei4BNA@mail.gmail.com>
Date: Fri, 11 Jan 2013 16:50:45 -0800
From: Doug Anderson <dianders@...omium.org>
To: Vivek Gautam <gautamvivek1987@...il.com>
Cc: Vivek Gautam <gautam.vivek@...sung.com>, linux-usb@...r.kernel.org,
yulgon.kim@...sung.com, linux-samsung-soc@...r.kernel.org,
Praveen Paneri <p.paneri@...sung.com>,
gregkh@...uxfoundation.org, devicetree-discuss@...ts.ozlabs.org,
jg1.han@...sung.com,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
balbi@...com, kishon@...com, Kukjin Kim <kgene.kim@...sung.com>,
Alan Stern <stern@...land.harvard.edu>,
Rob Herring <rob.herring@...xeda.com>,
Sylwester Nawrocki <sylvester.nawrocki@...il.com>
Subject: Re: [PATCH v5 2/4] usb: phy: samsung: Add host phy support to
samsung-phy driver
Vivek,
On Fri, Jan 11, 2013 at 4:40 AM, Vivek Gautam <gautamvivek1987@...il.com> 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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