From 3d27bc5c313ef9f953d1a8eb6927307cdda3aa52 Mon Sep 17 00:00:00 2001 From: Anson Huang Date: Wed, 10 Dec 2014 17:51:42 +0800 Subject: ARM: imx: correct the hardware clock gate setting for shared nodes 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, U-Boot 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. This patch adds .disable_unused callback and using hardware register check for .is_enabled callback of shared nodes to handle such scenario in late phase of kernel boot up, then the hardware status will match the clk tree info. Signed-off-by: Anson Huang Signed-off-by: Shawn Guo --- arch/arm/mach-imx/clk-gate2.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) (limited to 'arch') diff --git a/arch/arm/mach-imx/clk-gate2.c b/arch/arm/mach-imx/clk-gate2.c index 5a75cdc81891..8935bff99fe7 100644 --- a/arch/arm/mach-imx/clk-gate2.c +++ b/arch/arm/mach-imx/clk-gate2.c @@ -96,15 +96,30 @@ 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 void clk_gate2_disable_unused(struct clk_hw *hw) +{ + struct clk_gate2 *gate = to_clk_gate2(hw); + unsigned long flags = 0; + u32 reg; + + spin_lock_irqsave(gate->lock, flags); + + if (!gate->share_count || *gate->share_count == 0) { + reg = readl(gate->reg); + reg &= ~(3 << gate->bit_idx); + writel(reg, gate->reg); + } + + spin_unlock_irqrestore(gate->lock, flags); } static struct clk_ops clk_gate2_ops = { .enable = clk_gate2_enable, .disable = clk_gate2_disable, + .disable_unused = clk_gate2_disable_unused, .is_enabled = clk_gate2_is_enabled, }; -- cgit v1.2.2