clk: qcom: rcg2: Add support for display port clock ops

New display port clock ops supported for display port clocks.
Signed-off-by: Taniya Das <tdas@codeaurora.org>
Link: https://lkml.kernel.org/r/20190731182713.8123-2-tdas@codeaurora.orgSigned-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/qcom/Kconfig

@@ -14,6 +14,7 @@ menuconfig COMMON_CLK_QCOM
 	tristate "Support for Qualcomm's clock controllers"
 	depends on OF
 	depends on ARCH_QCOM || COMPILE_TEST
+	select RATIONAL
 	select REGMAP_MMIO
 	select RESET_CONTROLLER
 

drivers/clk/qcom/clk-rcg.h

@@ -161,6 +161,7 @@ extern const struct clk_ops clk_byte2_ops;
 extern const struct clk_ops clk_pixel_ops;
 extern const struct clk_ops clk_gfx3d_ops;
 extern const struct clk_ops clk_rcg2_shared_ops;
+extern const struct clk_ops clk_dp_ops;
 
 struct clk_rcg_dfs_data {
 	struct clk_rcg2 *rcg;

drivers/clk/qcom/clk-rcg2.c

@@ -10,6 +10,7 @@
 #include <linux/export.h>
 #include <linux/clk-provider.h>
 #include <linux/delay.h>
+#include <linux/rational.h>
 #include <linux/regmap.h>
 #include <linux/math64.h>
 #include <linux/slab.h>
@@ -1124,3 +1125,79 @@ int qcom_cc_register_rcg_dfs(struct regmap *regmap,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(qcom_cc_register_rcg_dfs);
+
+static int clk_rcg2_dp_set_rate(struct clk_hw *hw, unsigned long rate,
+			unsigned long parent_rate)
+{
+	struct clk_rcg2 *rcg = to_clk_rcg2(hw);
+	struct freq_tbl f = { 0 };
+	u32 mask = BIT(rcg->hid_width) - 1;
+	u32 hid_div, cfg;
+	int i, num_parents = clk_hw_get_num_parents(hw);
+	unsigned long num, den;
+
+	rational_best_approximation(parent_rate, rate,
+			GENMASK(rcg->mnd_width - 1, 0),
+			GENMASK(rcg->mnd_width - 1, 0), &den, &num);
+
+	if (!num || !den)
+		return -EINVAL;
+
+	regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + CFG_REG, &cfg);
+	hid_div = cfg;
+	cfg &= CFG_SRC_SEL_MASK;
+	cfg >>= CFG_SRC_SEL_SHIFT;
+
+	for (i = 0; i < num_parents; i++) {
+		if (cfg == rcg->parent_map[i].cfg) {
+			f.src = rcg->parent_map[i].src;
+			break;
+		}
+	}
+
+	f.pre_div = hid_div;
+	f.pre_div >>= CFG_SRC_DIV_SHIFT;
+	f.pre_div &= mask;
+
+	if (num != den) {
+		f.m = num;
+		f.n = den;
+	} else {
+		f.m = 0;
+		f.n = 0;
+	}
+
+	return clk_rcg2_configure(rcg, &f);
+}
+
+static int clk_rcg2_dp_set_rate_and_parent(struct clk_hw *hw,
+		unsigned long rate, unsigned long parent_rate, u8 index)
+{
+	return clk_rcg2_dp_set_rate(hw, rate, parent_rate);
+}
+
+static int clk_rcg2_dp_determine_rate(struct clk_hw *hw,
+				struct clk_rate_request *req)
+{
+	struct clk_rate_request parent_req = *req;
+	int ret;
+
+	ret = __clk_determine_rate(clk_hw_get_parent(hw), &parent_req);
+	if (ret)
+		return ret;
+
+	req->best_parent_rate = parent_req.rate;
+
+	return 0;
+}
+
+const struct clk_ops clk_dp_ops = {
+	.is_enabled = clk_rcg2_is_enabled,
+	.get_parent = clk_rcg2_get_parent,
+	.set_parent = clk_rcg2_set_parent,
+	.recalc_rate = clk_rcg2_recalc_rate,
+	.set_rate = clk_rcg2_dp_set_rate,
+	.set_rate_and_parent = clk_rcg2_dp_set_rate_and_parent,
+	.determine_rate = clk_rcg2_dp_determine_rate,
+};
+EXPORT_SYMBOL_GPL(clk_dp_ops);