From 9d3745d44a7faa7d24db7facb1949a1378162f3e Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Fri, 6 Mar 2015 15:41:53 -0800 Subject: [PATCH] clk: qcom: Properly change rates for ahbix clock The ahbix clock can never be turned off in practice. To change the rates we need to switch the mux off the M/N counter to an always on source (XO), reprogram the M/N counter to get the rate we want and finally switch back to the M/N counter. Add a new ops structure for this type of clock so that we can set the rate properly. Fixes: c99e515a92e9 "clk: qcom: Add IPQ806X LPASS clock controller (LCC) driver" Tested-by: Kenneth Westfield Signed-off-by: Stephen Boyd --- drivers/clk/qcom/clk-rcg.c | 62 ++++++++++++++++++++++++++++++++++ drivers/clk/qcom/clk-rcg.h | 1 + drivers/clk/qcom/lcc-ipq806x.c | 5 ++- 3 files changed, 65 insertions(+), 3 deletions(-) diff --git a/drivers/clk/qcom/clk-rcg.c b/drivers/clk/qcom/clk-rcg.c index 0039bd7d3965..466f30ca65c2 100644 --- a/drivers/clk/qcom/clk-rcg.c +++ b/drivers/clk/qcom/clk-rcg.c @@ -495,6 +495,57 @@ static int clk_rcg_bypass_set_rate(struct clk_hw *hw, unsigned long rate, return __clk_rcg_set_rate(rcg, rcg->freq_tbl); } +/* + * This type of clock has a glitch-free mux that switches between the output of + * the M/N counter and an always on clock source (XO). When clk_set_rate() is + * called we need to make sure that we don't switch to the M/N counter if it + * isn't clocking because the mux will get stuck and the clock will stop + * outputting a clock. This can happen if the framework isn't aware that this + * clock is on and so clk_set_rate() doesn't turn on the new parent. To fix + * this we switch the mux in the enable/disable ops and reprogram the M/N + * counter in the set_rate op. We also make sure to switch away from the M/N + * counter in set_rate if software thinks the clock is off. + */ +static int clk_rcg_lcc_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_rcg *rcg = to_clk_rcg(hw); + const struct freq_tbl *f; + int ret; + u32 gfm = BIT(10); + + f = qcom_find_freq(rcg->freq_tbl, rate); + if (!f) + return -EINVAL; + + /* Switch to XO to avoid glitches */ + regmap_update_bits(rcg->clkr.regmap, rcg->ns_reg, gfm, 0); + ret = __clk_rcg_set_rate(rcg, f); + /* Switch back to M/N if it's clocking */ + if (__clk_is_enabled(hw->clk)) + regmap_update_bits(rcg->clkr.regmap, rcg->ns_reg, gfm, gfm); + + return ret; +} + +static int clk_rcg_lcc_enable(struct clk_hw *hw) +{ + struct clk_rcg *rcg = to_clk_rcg(hw); + u32 gfm = BIT(10); + + /* Use M/N */ + return regmap_update_bits(rcg->clkr.regmap, rcg->ns_reg, gfm, gfm); +} + +static void clk_rcg_lcc_disable(struct clk_hw *hw) +{ + struct clk_rcg *rcg = to_clk_rcg(hw); + u32 gfm = BIT(10); + + /* Use XO */ + regmap_update_bits(rcg->clkr.regmap, rcg->ns_reg, gfm, 0); +} + static int __clk_dyn_rcg_set_rate(struct clk_hw *hw, unsigned long rate) { struct clk_dyn_rcg *rcg = to_clk_dyn_rcg(hw); @@ -543,6 +594,17 @@ const struct clk_ops clk_rcg_bypass_ops = { }; EXPORT_SYMBOL_GPL(clk_rcg_bypass_ops); +const struct clk_ops clk_rcg_lcc_ops = { + .enable = clk_rcg_lcc_enable, + .disable = clk_rcg_lcc_disable, + .get_parent = clk_rcg_get_parent, + .set_parent = clk_rcg_set_parent, + .recalc_rate = clk_rcg_recalc_rate, + .determine_rate = clk_rcg_determine_rate, + .set_rate = clk_rcg_lcc_set_rate, +}; +EXPORT_SYMBOL_GPL(clk_rcg_lcc_ops); + const struct clk_ops clk_dyn_rcg_ops = { .enable = clk_enable_regmap, .is_enabled = clk_is_enabled_regmap, diff --git a/drivers/clk/qcom/clk-rcg.h b/drivers/clk/qcom/clk-rcg.h index 687e41f91d7c..d09d06ba278e 100644 --- a/drivers/clk/qcom/clk-rcg.h +++ b/drivers/clk/qcom/clk-rcg.h @@ -96,6 +96,7 @@ struct clk_rcg { extern const struct clk_ops clk_rcg_ops; extern const struct clk_ops clk_rcg_bypass_ops; +extern const struct clk_ops clk_rcg_lcc_ops; #define to_clk_rcg(_hw) container_of(to_clk_regmap(_hw), struct clk_rcg, clkr) diff --git a/drivers/clk/qcom/lcc-ipq806x.c b/drivers/clk/qcom/lcc-ipq806x.c index 121ffde25dc3..5e4a3dafcf63 100644 --- a/drivers/clk/qcom/lcc-ipq806x.c +++ b/drivers/clk/qcom/lcc-ipq806x.c @@ -386,13 +386,12 @@ static struct clk_rcg ahbix_clk = { .freq_tbl = clk_tbl_ahbix, .clkr = { .enable_reg = 0x38, - .enable_mask = BIT(10), /* toggle the gfmux to select mn/pxo */ + .enable_mask = BIT(11), .hw.init = &(struct clk_init_data){ .name = "ahbix", .parent_names = lcc_pxo_pll4, .num_parents = 2, - .ops = &clk_rcg_ops, - .flags = CLK_SET_RATE_GATE, + .ops = &clk_rcg_lcc_ops, }, }, }; -- 2.20.1