From mboxrd@z Thu Jan  1 00:00:00 1970
From: kgene.kim@samsung.com (Kukjin Kim)
Date: Fri, 18 Jun 2010 11:31:40 +0900
Subject: [PATCH] S5PV210 Correct clock register properties
In-Reply-To: <1276763596-6175-1-git-send-email-myungjoo.ham@samsung.com>
References: <1276763596-6175-1-git-send-email-myungjoo.ham@samsung.com>
Message-ID: <000f01cb0e8e$64d44950$2e7cdbf0$%kim@samsung.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

MyungJoo Ham wrote:
> 
> From: MyungJoo Ham <myungJoo.ham@samsung.com>
> 
I think you're author of this patch, so no need above 'From'.
Maybe from wrong e-mail which should be 'myungjoo.ham...'

Please ensure that your setting of '.gitconfig' is right before submitting.

> Corrected shift values of I2S and UART clocks (CLK_GATE_IP3).
> 
> I2S (CLK_GATE_IP3) and UART (CLK_GATE_IP3) had wrong register shift
> values, which in turn, made them turn on and off wrong clocks.

Yes..should be fixed.

> 
> Please note that each clock definition should access different control
> register; otherwise, the system may suffer lockups. For example, if we
> have two clock definitions "a" and "b" which access the same register
> (and the shift value). Then, when we do:
> 
> 	module B
> 	1 clk = clk_get("b");
> 	2 clk->clk_enable(clk);
> 	3 do something with clk.
> 	4 clk->clk_disable(clk);
> 
> 	module A
> 	1 clk = clk_get("a");
> 	2 clk->clk_enable(clk);
> 	3 do something with clk
> 	4 clk->clk_disable(clk);
> 
> 	And if the execution order is
> 
> 	B1->B2->A1->A2->A3->A4->B3 ...
> 
> 	Then, the system may hang at the point B3.
> 
> 
> Therefore, there should be no clock definitions with the same contol
> register/shift. If we need to create "aliases", then, creating child
> clocks sharing the clock should be fine.

Yeah, but actually just should be fixed wrong bit.

> 
> However, we did not mitigate this doppelganger clock problem for "struct
> clksrc_clk" vs "struct clk"; look at "hsmmc" vs "mmc_bus". In the next
> patch, we plan to let "struct clksrc_clk" access "CLK_SRC_MASK0" and
> "CLK_SRC_MASK1"; i.e., clock source enable/disable should mask the clock
> source itself, not the clock that is supplied by the clock source.

No need above message in here.

> 
> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
> ---
>  arch/arm/mach-s5pv210/clock.c |   12 ++++++------
>  1 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm/mach-s5pv210/clock.c b/arch/arm/mach-s5pv210/clock.c
> index 154bca4..ec5ad8c 100644
> --- a/arch/arm/mach-s5pv210/clock.c
> +++ b/arch/arm/mach-s5pv210/clock.c
> @@ -406,13 +406,13 @@ static struct clk init_clocks_disable[] = {
>  		.id		= 0,
>  		.parent		= &clk_p,
>  		.enable		= s5pv210_clk_ip3_ctrl,
> -		.ctrlbit	= (1<<4),
> +		.ctrlbit	= (1<<5),
>  	}, {
>  		.name		= "i2s_v32",
>  		.id		= 1,
>  		.parent		= &clk_p,
>  		.enable		= s5pv210_clk_ip3_ctrl,
> -		.ctrlbit	= (1<<4),
> +		.ctrlbit	= (1<<6),

Your point is right..but your updated code was wrong :-(

Should be like below.

@@ -400,19 +400,19 @@ static struct clk init_clocks_disable[] = {
 		.id		= 0,
 		.parent		= &clk_p,
 		.enable		= s5pv210_clk_ip3_ctrl,
-		.ctrlbit	= (1<<4),
+		.ctrlbit	= (1 << 4),
 	}, {
 		.name		= "i2s_v32",
 		.id		= 0,
 		.parent		= &clk_p,
 		.enable		= s5pv210_clk_ip3_ctrl,
-		.ctrlbit	= (1<<4),
+		.ctrlbit	= (1 << 5),
 	}, {
 		.name		= "i2s_v32",
 		.id		= 1,
 		.parent		= &clk_p,
 		.enable		= s5pv210_clk_ip3_ctrl,
-		.ctrlbit	= (1<<4),
+		.ctrlbit	= (1 << 6),

>  	}
>  };
> 
> @@ -429,25 +429,25 @@ static struct clk init_clocks[] = {
>  		.id		= 0,
>  		.parent		= &clk_pclk_psys.clk,
>  		.enable		= s5pv210_clk_ip3_ctrl,
> -		.ctrlbit	= (1<<7),
> +		.ctrlbit	= (1<<17),
>  	}, {
>  		.name		= "uart",
>  		.id		= 1,
>  		.parent		= &clk_pclk_psys.clk,
>  		.enable		= s5pv210_clk_ip3_ctrl,
> -		.ctrlbit	= (1<<8),
> +		.ctrlbit	= (1<<18),
>  	}, {
>  		.name		= "uart",
>  		.id		= 2,
>  		.parent		= &clk_pclk_psys.clk,
>  		.enable		= s5pv210_clk_ip3_ctrl,
> -		.ctrlbit	= (1<<9),
> +		.ctrlbit	= (1<<19),
>  	}, {
>  		.name		= "uart",
>  		.id		= 3,
>  		.parent		= &clk_pclk_psys.clk,
>  		.enable		= s5pv210_clk_ip3_ctrl,
> -		.ctrlbit	= (1<<10),
> +		.ctrlbit	= (1<<20),

How about adding blank on both of '<<' like (1 << x) for easily reading?

>  	},
>  };
> 
> --

Thanks.

Best regards,
Kgene.
--
Kukjin Kim <kgene.kim@samsung.com>, Senior Engineer,
SW Solution Development Team, Samsung Electronics Co., Ltd.