diff options
author | Kuninori Morimoto | 2012-10-29 01:14:41 -0700 |
---|---|---|
committer | Simon Horman | 2012-11-07 17:11:34 +0900 |
commit | 0a3842900429c2b59fe5d5d9c182cb8f63bd955c (patch) | |
tree | 09ff3b8572980ea05471380398329541f47e3153 /arch/arm/mach-shmobile | |
parent | 167443b16e3b9875e0541701b96e4009be8360f0 (diff) |
ARM: shmobile: r8a7740: add USB24 clock explain
USBCKCR is controlling USB parent clock and divide rate.
This parent clock is used as a "usb24s" from other devices,
but the "divide rate" is not used.
Further, this clock itself is known as "usb24".
So, to set this clock is a little confusable.
This patch adds quick explain and sample settings for this clock.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Diffstat (limited to 'arch/arm/mach-shmobile')
-rw-r--r-- | arch/arm/mach-shmobile/clock-r8a7740.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/arm/mach-shmobile/clock-r8a7740.c b/arch/arm/mach-shmobile/clock-r8a7740.c index 6729e0032180..c012bbf4e05c 100644 --- a/arch/arm/mach-shmobile/clock-r8a7740.c +++ b/arch/arm/mach-shmobile/clock-r8a7740.c @@ -188,6 +188,22 @@ static struct clk pllc1_div2_clk = { }; /* USB clock */ +/* + * USBCKCR is controlling usb24 clock + * bit[7] : parent clock + * bit[6] : clock divide rate + * And this bit[7] is used as a "usb24s" from other devices. + * (Video clock / Sub clock / SPU clock) + * You can controll this clock as a below. + * + * struct clk *usb24 = clk_get(dev, "usb24"); + * struct clk *usb24s = clk_get(NULL, "usb24s"); + * struct clk *system = clk_get(NULL, "system_clk"); + * int rate = clk_get_rate(system); + * + * clk_set_parent(usb24s, system); // for bit[7] + * clk_set_rate(usb24, rate / 2); // for bit[6] + */ static struct clk *usb24s_parents[] = { [0] = &system_clk, [1] = &extal2_clk |