[U-Boot] [PATCH v2] arm: exynos: change to use clrbits macro instead of readl/writel function

[Jaehoon Chung <jh80.chung@samsung.com>]

On 01/16/2014 05:34 PM, Minkyu Kang wrote:
> On 16/01/14 17:20, Inha Song wrote:
>>
>> Hi,
>>
>> On Thu, 16 Jan 2014 16:50:37 +0900
>> Minkyu Kang <mk7.kang@samsung.com> wrote:
>>
>>> On 15/01/14 14:27, Inha Song wrote:
>>>> Use setbits/clrbits macro instead of readl/writel function
>>>>
>>>> Signed-off-by: Inha Song <ideal.song@samsung.com>
>>>> Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
>>>> Tested-by: Przemyslaw Marczak <p.marczak@samsung.com>
>>>> ---
>>>> Changes for v2:
>>>> - Coding Style cleanup
>>>> - add signed-off-by
>>>>
>>>>  arch/arm/cpu/armv7/exynos/clock.c |   82 +++++++++----------------------------
>>>>  1 file changed, 20 insertions(+), 62 deletions(-)
>>>   
>>>>  	/*
>>>>  	 * CLK_SRC_LCD0
>>>> @@ -1085,10 +1070,7 @@ void exynos4_set_lcd_clk(void)
>>>>  	 * MIPI0_SEL		[12:15]
>>>>  	 * set lcd0 src clock 0x6: SCLK_MPLL
>>>>  	 */
>>>> -	cfg = readl(&clk->src_lcd0);
>>>> -	cfg &= ~(0xf);
>>>> -	cfg |= 0x6;
>>>> -	writel(cfg, &clk->src_lcd0);
>>>> +	clrsetbits_le32(&clk->src_lcd0, 0x9, 0x6);
>>>
>>> 0x9? It seems to be 0xf.
>>
>> I have set the only bit that must be cleared.
>>
>> In case, I want to set src_lcd0 register to 0x6(b0110).
>> Therefore, do not need to clear a bit of the second and third. (don't care bits)
>>
>> clrsetbits_le32(addr, 0x9, 0x6) == clrsetbits_le32(addr, 0xf, 0x6)
>> ( reg &= ~b1xx1, reg |= b0110 == reg &= ~b1111, reg |= b0110 )
>>
>> Do you think any way is better?
>>
> 
> No..
> 0xF is mask of FIMD0_SEL that is 4 bits.
> The mask value never be changed.
Right, It's not "don't care bit".
If we want to change the source clock, just change the last argument.
It's not fixed 0x6 as source clock.

Best Regards,
Jaehoon Chung

> 
> Thanks,
> Minkyu Kang.
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