From mboxrd@z Thu Jan 1 00:00:00 1970 From: s.hauer@pengutronix.de (Sascha Hauer) Date: Tue, 9 Dec 2014 09:46:53 +0100 Subject: [PATCH] arm: imx: correct the hardware clock gate setting for shared nodes In-Reply-To: <1418111885-3623-1-git-send-email-b20788@freescale.com> References: <1418111885-3623-1-git-send-email-b20788@freescale.com> Message-ID: <20141209084653.GR14482@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On Tue, Dec 09, 2014 at 03:58:05PM +0800, Anson Huang wrote: > For those clk gates which hold share count, since its is_enabled > callback is only checking the share count rather than reading > the hardware register setting, in the late phase of kernel bootup, > the clk_disable_unused action will NOT handle the scenario of > share_count is 0 but the hardware setting is enabled, actually, > uboot normally enables all clk gates, then those shared clk gates > will be always enabled until they are used by some modules. > > So the problem would be: when kernel boot up, the usecount cat > from clk tree is 0, but the clk gates actually is enabled in > hardware register, it will confuse user and bring unnecessary power > consumption, take i.MX6SX for example, the ESAI clk info > is as below, the use count is 0, but the hardware register read > from CCM_CCGR1_CG8 is ungated. I believe the problem is that the shared count is not increased correctly during registration. When it would be increased during registration for each clock that is enabled in hardware clock_disable_unused could do its job like intended. Could you test the attached patch? -------------------------------8<-------------------------- >>From 8095ee6e407f33887b2afa504767d00fcca4f10c Mon Sep 17 00:00:00 2001 From: Sascha Hauer Date: Tue, 9 Dec 2014 09:39:06 +0100 Subject: [PATCH] ARM: i.MX: clk-gate2: Fix shared clock enable counting When during registration of a shared clock the clock is enabled in hardware the shared_count must be increased. This makes sure that during clk_disable the shared_count is decreased first before actually diabling the clock. When done like this the is_enabled callback can return the hardware state of the clock, like it is intended. Signed-off-by: Sascha Hauer --- arch/arm/mach-imx/clk-gate2.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/arm/mach-imx/clk-gate2.c b/arch/arm/mach-imx/clk-gate2.c index 5a75cdc..a673364 100644 --- a/arch/arm/mach-imx/clk-gate2.c +++ b/arch/arm/mach-imx/clk-gate2.c @@ -96,10 +96,7 @@ static int clk_gate2_is_enabled(struct clk_hw *hw) { struct clk_gate2 *gate = to_clk_gate2(hw); - if (gate->share_count) - return !!__clk_get_enable_count(hw->clk); - else - return clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx); + return clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx); } static struct clk_ops clk_gate2_ops = { @@ -129,6 +126,9 @@ struct clk *clk_register_gate2(struct device *dev, const char *name, gate->lock = lock; gate->share_count = share_count; + if (share_count && clk_gate2_reg_is_enabled(reg, bit_idx)) + (*share_count)++; + init.name = name; init.ops = &clk_gate2_ops; init.flags = flags; -- 2.1.3 -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |