From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joonyoung Shim <jy0922.shim@samsung.com>
Date: Wed, 04 Feb 2015 15:36:59 +0900
Subject: [U-Boot] [PATCH v5 7/7] Exynos: Clock: Cleanup
	soc_get_periph_rate
In-Reply-To: <1423031448-4538-1-git-send-email-akshay.s@samsung.com>
References: <1423031448-4538-1-git-send-email-akshay.s@samsung.com>
Message-ID: <54D1BE0B.2010701@samsung.com>
List-Id: <u-boot.lists.denx.de>
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To: u-boot@lists.denx.de

Hi,

On 02/04/2015 03:30 PM, Akshay Saraswat wrote:
> Hi,
> 
>> Hi Akshay,
>>
>> On 02/03/2015 05:27 PM, Akshay Saraswat wrote:
>>> Cleaning up soc_get_periph_rate to make the logic easy to
>>> comprehend.
>>>
>>
>> Could you give more detailed description?
> 
> We did just a cleanup here by removing I2C sepecific calculations
> because we can now have a generic div and pre-div calculation.
> Only intention of doing it is making code clean and easily understandable.
> I don't know what else to write for that. Please suggest. :)
> 

I mean you should write commit messages in detail about how is this
more easier logic?

>>
>>> Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
>>> ---
>>> Changes since v4:
>>> 	- New patch.
>>>
>>>  arch/arm/cpu/armv7/exynos/clock.c | 76 +++++++++++++++++----------------------
>>>  1 file changed, 33 insertions(+), 43 deletions(-)
>>>
>>> diff --git a/arch/arm/cpu/armv7/exynos/clock.c b/arch/arm/cpu/armv7/exynos/clock.c
>>> index 3884d4b..8724bc7 100644
>>> --- a/arch/arm/cpu/armv7/exynos/clock.c
>>> +++ b/arch/arm/cpu/armv7/exynos/clock.c
>>> @@ -366,8 +366,8 @@ static struct clk_bit_info *get_clk_bit_info(int peripheral)
>>>  static unsigned long exynos5_get_periph_rate(int peripheral)
>>>  {
>>>  	struct clk_bit_info *bit_info = get_clk_bit_info(peripheral);
>>> -	unsigned long sclk, sub_clk = 0;
>>> -	unsigned int src, div, sub_div = 0;
>>> +	unsigned long sclk = 0;
>>> +	unsigned int src = 0, div = 0, sub_div = 0;
>>>  	struct exynos5_clock *clk =
>>>  			(struct exynos5_clock *)samsung_get_base_clock();
>>>  
>>> @@ -389,30 +389,30 @@ static unsigned long exynos5_get_periph_rate(int peripheral)
>>>  		break;
>>>  	case PERIPH_ID_I2S0:
>>>  		src = readl(&clk->src_mau);
>>> -		div = readl(&clk->div_mau);
>>> +		div = sub_div = readl(&clk->div_mau);
>>>  	case PERIPH_ID_SPI0:
>>>  	case PERIPH_ID_SPI1:
>>>  		src = readl(&clk->src_peric1);
>>> -		div = readl(&clk->div_peric1);
>>> +		div = sub_div = readl(&clk->div_peric1);
>>>  		break;
>>>  	case PERIPH_ID_SPI2:
>>>  		src = readl(&clk->src_peric1);
>>> -		div = readl(&clk->div_peric2);
>>> +		div = sub_div = readl(&clk->div_peric2);
>>>  		break;
>>>  	case PERIPH_ID_SPI3:
>>>  	case PERIPH_ID_SPI4:
>>>  		src = readl(&clk->sclk_src_isp);
>>> -		div = readl(&clk->sclk_div_isp);
>>> +		div = sub_div = readl(&clk->sclk_div_isp);
>>>  		break;
>>>  	case PERIPH_ID_SDMMC0:
>>>  	case PERIPH_ID_SDMMC1:
>>>  		src = readl(&clk->src_fsys);
>>> -		div = readl(&clk->div_fsys1);
>>> +		div = sub_div = readl(&clk->div_fsys1);
>>>  		break;
>>>  	case PERIPH_ID_SDMMC2:
>>>  	case PERIPH_ID_SDMMC3:
>>>  		src = readl(&clk->src_fsys);
>>> -		div = readl(&clk->div_fsys2);
>>> +		div = sub_div = readl(&clk->div_fsys2);
>>>  		break;
>>>  	case PERIPH_ID_I2C0:
>>>  	case PERIPH_ID_I2C1:
>>> @@ -422,12 +422,10 @@ static unsigned long exynos5_get_periph_rate(int peripheral)
>>>  	case PERIPH_ID_I2C5:
>>>  	case PERIPH_ID_I2C6:
>>>  	case PERIPH_ID_I2C7:
>>> -		sclk = exynos5_get_pll_clk(MPLL);
>>> -		sub_div = ((readl(&clk->div_top1) >> bit_info->div_bit)
>>> -			    & bit_info->div_mask) + 1;
>>> -		div = ((readl(&clk->div_top0) >> bit_info->prediv_bit)
>>> -			& bit_info->prediv_mask) + 1;
>>> -		return (sclk / sub_div) / div;
>>> +		src = EXYNOS_SRC_MPLL;
>>> +		div = readl(&clk->div_top0);
>>> +		sub_div = readl(&clk->div_top1);
>>> +		break;
>>>  	default:
>>>  		debug("%s: invalid peripheral %d", __func__, peripheral);
>>>  		return -1;
>>> @@ -446,29 +444,26 @@ static unsigned long exynos5_get_periph_rate(int peripheral)
>>>  	case EXYNOS_SRC_VPLL:
>>>  		sclk = exynos5_get_pll_clk(VPLL);
>>>  		break;
>>> -	default:
>>> -		return 0;
>>
>> Why remove? I think it's better to use default label and also how about
>> add debug log?
> 
> Removing because anyways we are going to calculate & return 0 for non-existent
> src or sclk. I have initialized src and sclk above with value zero.
> 

I think it's good coding style to use default case, later we can detect
wrong src cases when wrong any codes or read wrong values from register.

Thanks.