clk: qcom: clk-alpha-pll: introduce stromer plus ops

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.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Kathiravan T <quic_kathirav@quicinc.com>
Signed-off-by: Varadarajan Narayanan <quic_varada@quicinc.com>
Link: https://lore.kernel.org/r/2affa6c63ff0c4342230623a7d4eef02ec7c02d4.1697781921.git.quic_varada@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Author: quic-varada

drivers/clk/qcom/clk-alpha-pll.c

@@ -2508,3 +2508,66 @@ 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, pll_mode;
+	u64 a;
+
+	rate = alpha_pll_round_rate(rate, prate, &l, &a, alpha_width);
+
+	ret = regmap_read(pll->clkr.regmap, PLL_MODE(pll), &pll_mode);
+	if (ret)
+		return ret;
+
+	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;
+	}
+
+	if (pll_mode & PLL_OUTCTRL)
+		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);

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;