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[1/6] ARM: dove: unify clock setup

Message ID 1344255815-4457-2-git-send-email-sebastian.hesselbarth@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Sebastian Hesselbarth Aug. 6, 2012, 12:23 p.m. UTC 
This patch synchronizes the clock setup of dove with other orion-based
platforms.

In dove_find_tclk there was a note about DOVE_SAMPLE_HI/LO register to
detect tclk. While it might be possible to set a different tclk frequency 
with reset strapping the Dove datasheets don't tell anything about tclk 
frequency here. Therefore, I removed that comment.

Also, the patch ensures that tclk is always clocked by prepare/enable.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: Rabeeh Khoury <rabeeh@solid-run.com>
Cc: Ian Molton <ian.molton@codethink.co.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Maen Suleiman <maen@marvell.com>
Cc: Olof Johansson <olof@lixom.net>
---
 arch/arm/mach-dove/common.c |   22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

Comments

Andrew Lunn Aug. 11, 2012, 9:12 a.m. UTC | #1 
Hi Sebastian

> -static void __init clk_init(void)
> +static void __init dove_clk_init(void)
>  {
>  	tclk = clk_register_fixed_rate(NULL, "tclk", NULL, CLK_IS_ROOT,
> -				       get_tclk());
> +				       dove_tclk);
>  
>  	orion_clkdev_init(tclk);
> +
> +	/* Ensure tclk is always clocked */
> +	clk_prepare_enable(tclk);
>  }

"ticking" would be better than clocked. 

Since this is a root fixed clock, is it necessary to prepare_enable()
it? I think prepare and enable become NOPs in this situation.

    Andrew
Sebastian Hesselbarth Aug. 11, 2012, 9:38 a.m. UTC | #2 
On 08/11/2012 11:12 AM, Andrew Lunn wrote:
>> +	/* Ensure tclk is always clocked */
>> +	clk_prepare_enable(tclk);
>>   }
>
> "ticking" would be better than clocked.
>
> Since this is a root fixed clock, is it necessary to prepare_enable()
> it? I think prepare and enable become NOPs in this situation.

Hi Andrew,

yes you are right, it is useless to prepare or enable a fixed rate clk.
I cannot be gated anyway. I'll update the patch and resend soon.

Sebastian
diff mbox

Patch

diff --git a/arch/arm/mach-dove/common.c b/arch/arm/mach-dove/common.c
index 4db5de5..20b765c 100644
--- a/arch/arm/mach-dove/common.c
+++ b/arch/arm/mach-dove/common.c
@@ -33,8 +33,6 @@ 
 #include <plat/addr-map.h>
 #include "common.h"
 
-static int get_tclk(void);
-
 /*****************************************************************************
  * I/O Address Mapping
  ****************************************************************************/
@@ -70,14 +68,18 @@  void __init dove_map_io(void)
 /*****************************************************************************
  * CLK tree
  ****************************************************************************/
+static int dove_tclk;
 static struct clk *tclk;
 
-static void __init clk_init(void)
+static void __init dove_clk_init(void)
 {
 	tclk = clk_register_fixed_rate(NULL, "tclk", NULL, CLK_IS_ROOT,
-				       get_tclk());
+				       dove_tclk);
 
 	orion_clkdev_init(tclk);
+
+	/* Ensure tclk is always clocked */
+	clk_prepare_enable(tclk);
 }
 
 /*****************************************************************************
@@ -187,16 +189,16 @@  void __init dove_init_early(void)
 	orion_time_set_base(TIMER_VIRT_BASE);
 }
 
-static int get_tclk(void)
+static int __init dove_find_tclk(void)
 {
-	/* use DOVE_RESET_SAMPLE_HI/LO to detect tclk */
 	return 166666667;
 }
 
 static void __init dove_timer_init(void)
 {
+	dove_tclk = dove_find_tclk();
 	orion_time_init(BRIDGE_VIRT_BASE, BRIDGE_INT_TIMER1_CLR,
-			IRQ_DOVE_BRIDGE, get_tclk());
+			IRQ_DOVE_BRIDGE, dove_tclk);
 }
 
 struct sys_timer dove_timer = {
@@ -284,8 +286,8 @@  void __init dove_sdio1_init(void)
 
 void __init dove_init(void)
 {
-	printk(KERN_INFO "Dove 88AP510 SoC, ");
-	printk(KERN_INFO "TCLK = %dMHz\n", (get_tclk() + 499999) / 1000000);
+	pr_info("Dove 88AP510 SoC, TCLK = %d MHz.\n",
+		(dove_tclk + 499999) / 1000000);
 
 #ifdef CONFIG_CACHE_TAUROS2
 	tauros2_init();
@@ -293,7 +295,7 @@  void __init dove_init(void)
 	dove_setup_cpu_mbus();
 
 	/* Setup root of clk tree */
-	clk_init();
+	dove_clk_init();
 
 	/* internal devices that every board has */
 	dove_rtc_init();