Stromer plus APSS PLL does not support dynamic frequency scaling.
To switch between frequencies, we have to shut down the PLL,
configure the L and ALPHA values and turn on again. So introduce the
separate set of ops for Stromer Plus PLL.
Signed-off-by: Kathiravan T <[email protected]>
Signed-off-by: Varadarajan Narayanan <[email protected]>
---
v3: Use prepare/unprepare instead of disable/enable in clk_alpha_pll_stromer_plus_ops
v2: Use clk_alpha_pll_stromer_determine_rate, instead of adding new
clk_alpha_pll_stromer_plus_determine_rate as the alpha pll width
is same for both
Fix review comments
udelay(50) -> usleep_range(50, 60)
Remove SoC-specific from print message
---
drivers/clk/qcom/clk-alpha-pll.c | 57 ++++++++++++++++++++++++++++++++++++++++
drivers/clk/qcom/clk-alpha-pll.h | 1 +
2 files changed, 58 insertions(+)
diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
index 4edbf77..f839a31 100644
--- a/drivers/clk/qcom/clk-alpha-pll.c
+++ b/drivers/clk/qcom/clk-alpha-pll.c
@@ -2508,3 +2508,60 @@ const struct clk_ops clk_alpha_pll_stromer_ops = {
.set_rate = clk_alpha_pll_stromer_set_rate,
};
EXPORT_SYMBOL_GPL(clk_alpha_pll_stromer_ops);
+
+static int clk_alpha_pll_stromer_plus_set_rate(struct clk_hw *hw,
+ unsigned long rate,
+ unsigned long prate)
+{
+ struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
+ u32 l, alpha_width = pll_alpha_width(pll);
+ int ret;
+ u64 a;
+
+ rate = alpha_pll_round_rate(rate, prate, &l, &a, alpha_width);
+
+ regmap_write(pll->clkr.regmap, PLL_MODE(pll), 0);
+
+ /* Delay of 2 output clock ticks required until output is disabled */
+ udelay(1);
+
+ regmap_write(pll->clkr.regmap, PLL_L_VAL(pll), l);
+
+ if (alpha_width > ALPHA_BITWIDTH)
+ a <<= alpha_width - ALPHA_BITWIDTH;
+
+ regmap_write(pll->clkr.regmap, PLL_ALPHA_VAL(pll), a);
+ regmap_write(pll->clkr.regmap, PLL_ALPHA_VAL_U(pll),
+ a >> ALPHA_BITWIDTH);
+
+ regmap_write(pll->clkr.regmap, PLL_MODE(pll), PLL_BYPASSNL);
+
+ /* Wait five micro seconds or more */
+ udelay(5);
+ regmap_update_bits(pll->clkr.regmap, PLL_MODE(pll), PLL_RESET_N,
+ PLL_RESET_N);
+
+ /* The lock time should be less than 50 micro seconds worst case */
+ usleep_range(50, 60);
+
+ ret = wait_for_pll_enable_lock(pll);
+ if (ret) {
+ pr_err("Wait for PLL enable lock failed [%s] %d\n",
+ clk_hw_get_name(hw), ret);
+ return ret;
+ }
+ regmap_update_bits(pll->clkr.regmap, PLL_MODE(pll), PLL_OUTCTRL,
+ PLL_OUTCTRL);
+
+ return 0;
+}
+
+const struct clk_ops clk_alpha_pll_stromer_plus_ops = {
+ .prepare = clk_alpha_pll_enable,
+ .unprepare = clk_alpha_pll_disable,
+ .is_enabled = clk_alpha_pll_is_enabled,
+ .recalc_rate = clk_alpha_pll_recalc_rate,
+ .determine_rate = clk_alpha_pll_stromer_determine_rate,
+ .set_rate = clk_alpha_pll_stromer_plus_set_rate,
+};
+EXPORT_SYMBOL_GPL(clk_alpha_pll_stromer_plus_ops);
diff --git a/drivers/clk/qcom/clk-alpha-pll.h b/drivers/clk/qcom/clk-alpha-pll.h
index 3b24a66..a1a75bb 100644
--- a/drivers/clk/qcom/clk-alpha-pll.h
+++ b/drivers/clk/qcom/clk-alpha-pll.h
@@ -152,6 +152,7 @@ extern const struct clk_ops clk_alpha_pll_postdiv_ops;
extern const struct clk_ops clk_alpha_pll_huayra_ops;
extern const struct clk_ops clk_alpha_pll_postdiv_ro_ops;
extern const struct clk_ops clk_alpha_pll_stromer_ops;
+extern const struct clk_ops clk_alpha_pll_stromer_plus_ops;
extern const struct clk_ops clk_alpha_pll_fabia_ops;
extern const struct clk_ops clk_alpha_pll_fixed_fabia_ops;
--
2.7.4
Quoting Varadarajan Narayanan (2023-10-18 02:29:14)
> diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
> index 4edbf77..f839a31 100644
> --- a/drivers/clk/qcom/clk-alpha-pll.c
> +++ b/drivers/clk/qcom/clk-alpha-pll.c
> @@ -2508,3 +2508,60 @@ const struct clk_ops clk_alpha_pll_stromer_ops = {
> .set_rate = clk_alpha_pll_stromer_set_rate,
> };
> EXPORT_SYMBOL_GPL(clk_alpha_pll_stromer_ops);
> +
> +static int clk_alpha_pll_stromer_plus_set_rate(struct clk_hw *hw,
> + unsigned long rate,
> + unsigned long prate)
> +{
> + struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
> + u32 l, alpha_width = pll_alpha_width(pll);
> + int ret;
> + u64 a;
> +
> + rate = alpha_pll_round_rate(rate, prate, &l, &a, alpha_width);
> +
> + regmap_write(pll->clkr.regmap, PLL_MODE(pll), 0);
It still assumes the clk is always enabled. Please read back the
register value and make sure the PLL was already enabled before
restoring the enable state of the clk.
> +
> + /* Delay of 2 output clock ticks required until output is disabled */
> + udelay(1);