From d042877aa7a36e7a5e0bb8c60dcd86e939f205c9 Mon Sep 17 00:00:00 2001 From: Georgi Djakov Date: Thu, 17 Sep 2015 19:39:27 +0300 Subject: clk: qcom: Add support for RCGs with shared branches Some root clock generators may have child branches that are controlled by different CPUs. These RCGs require some special operations: - some enable bits have to be toggled when we set the rate; - if RCG is disabled we only cache the rate and set it later when enabled; - when the RCG is disabled, the mux is set to the safe source; Signed-off-by: Georgi Djakov [sboyd@codeaurora.org: Simplify recalc_rate implementation] Signed-off-by: Stephen Boyd --- drivers/clk/qcom/clk-rcg2.c | 79 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) (limited to 'drivers/clk/qcom/clk-rcg2.c') diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c index d941dea6f7c7..b544bb302f79 100644 --- a/drivers/clk/qcom/clk-rcg2.c +++ b/drivers/clk/qcom/clk-rcg2.c @@ -300,6 +300,85 @@ const struct clk_ops clk_rcg2_ops = { }; EXPORT_SYMBOL_GPL(clk_rcg2_ops); +static int clk_rcg2_shared_force_enable(struct clk_hw *hw, unsigned long rate) +{ + struct clk_rcg2 *rcg = to_clk_rcg2(hw); + const char *name = clk_hw_get_name(hw); + int ret, count; + + /* force enable RCG */ + ret = regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + CMD_REG, + CMD_ROOT_EN, CMD_ROOT_EN); + if (ret) + return ret; + + /* wait for RCG to turn ON */ + for (count = 500; count > 0; count--) { + ret = clk_rcg2_is_enabled(hw); + if (ret) + break; + udelay(1); + } + if (!count) + pr_err("%s: RCG did not turn on\n", name); + + /* set clock rate */ + ret = __clk_rcg2_set_rate(hw, rate); + if (ret) + return ret; + + /* clear force enable RCG */ + return regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + CMD_REG, + CMD_ROOT_EN, 0); +} + +static int clk_rcg2_shared_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_rcg2 *rcg = to_clk_rcg2(hw); + + /* cache the rate */ + rcg->current_freq = rate; + + if (!__clk_is_enabled(hw->clk)) + return 0; + + return clk_rcg2_shared_force_enable(hw, rcg->current_freq); +} + +static unsigned long +clk_rcg2_shared_recalc_rate(struct clk_hw *hw, unsigned long parent_rate) +{ + struct clk_rcg2 *rcg = to_clk_rcg2(hw); + + return rcg->current_freq = clk_rcg2_recalc_rate(hw, parent_rate); +} + +static int clk_rcg2_shared_enable(struct clk_hw *hw) +{ + struct clk_rcg2 *rcg = to_clk_rcg2(hw); + + return clk_rcg2_shared_force_enable(hw, rcg->current_freq); +} + +static void clk_rcg2_shared_disable(struct clk_hw *hw) +{ + struct clk_rcg2 *rcg = to_clk_rcg2(hw); + + /* switch to XO, which is the lowest entry in the freq table */ + clk_rcg2_shared_set_rate(hw, rcg->freq_tbl[0].freq, 0); +} + +const struct clk_ops clk_rcg2_shared_ops = { + .enable = clk_rcg2_shared_enable, + .disable = clk_rcg2_shared_disable, + .get_parent = clk_rcg2_get_parent, + .recalc_rate = clk_rcg2_shared_recalc_rate, + .determine_rate = clk_rcg2_determine_rate, + .set_rate = clk_rcg2_shared_set_rate, +}; +EXPORT_SYMBOL_GPL(clk_rcg2_shared_ops); + struct frac_entry { int num; int den; -- cgit v1.2.3