From 8b4f6b8d59c614477ce65da15a4f5ddc31b2c398 Mon Sep 17 00:00:00 2001 From: Chunyan Zhang Date: Wed, 27 May 2020 13:36:35 +0800 Subject: [PATCH] clk: sprd: check its parent status before reading gate clock Some clocks only can be accessed if their parent is enabled. mipi_csi_xx clocks on SC9863A are an examples. We have to ensure the parent clock is enabled when reading those clocks. Signed-off-by: Chunyan Zhang Link: https://lkml.kernel.org/r/20200527053638.31439-2-zhang.lyra@gmail.com Signed-off-by: Stephen Boyd --- drivers/clk/sprd/gate.c | 7 +++++++ drivers/clk/sprd/gate.h | 9 +++++++++ 2 files changed, 16 insertions(+) diff --git a/drivers/clk/sprd/gate.c b/drivers/clk/sprd/gate.c index 574cfc1..56e1714 100644 --- a/drivers/clk/sprd/gate.c +++ b/drivers/clk/sprd/gate.c @@ -94,8 +94,15 @@ static int sprd_gate_is_enabled(struct clk_hw *hw) { struct sprd_gate *sg = hw_to_sprd_gate(hw); struct sprd_clk_common *common = &sg->common; + struct clk_hw *parent; unsigned int reg; + if (sg->flags & SPRD_GATE_NON_AON) { + parent = clk_hw_get_parent(hw); + if (!parent || !clk_hw_is_enabled(parent)) + return 0; + } + regmap_read(common->regmap, common->reg, ®); if (sg->flags & CLK_GATE_SET_TO_DISABLE) diff --git a/drivers/clk/sprd/gate.h b/drivers/clk/sprd/gate.h index b558178..e738daf 100644 --- a/drivers/clk/sprd/gate.h +++ b/drivers/clk/sprd/gate.h @@ -19,6 +19,15 @@ struct sprd_gate { struct sprd_clk_common common; }; +/* + * sprd_gate->flags is used for: + * CLK_GATE_SET_TO_DISABLE BIT(0) + * CLK_GATE_HIWORD_MASK BIT(1) + * CLK_GATE_BIG_ENDIAN BIT(2) + * so we define new flags from BIT(3) + */ +#define SPRD_GATE_NON_AON BIT(3) /* not alway powered on, check before read */ + #define SPRD_SC_GATE_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, \ _sc_offset, _enable_mask, _flags, \ _gate_flags, _udelay, _ops, _fn) \ -- 2.7.4