From mboxrd@z Thu Jan  1 00:00:00 1970
From: Minkyu Kang <mk7.kang@samsung.com>
Date: Thu, 16 Jan 2014 17:34:54 +0900
Subject: [U-Boot] [PATCH v2] arm: exynos: change to use clrbits macro
 instead of readl/writel function
In-Reply-To: <20140116172046.4a40b71d@songinha-Samsung-DeskTop-System>
References: <20140115142759.66afd1ce@songinha-Samsung-DeskTop-System>
	<52D78F4D.5020208@samsung.com>
	<20140116172046.4a40b71d@songinha-Samsung-DeskTop-System>
Message-ID: <52D799AE.70909@samsung.com>
List-Id: <u-boot.lists.denx.de>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
To: u-boot@lists.denx.de

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.

Thanks,
Minkyu Kang.