ufs: use PM OPP when scaling gears

Scaling gears requires not only scaling clocks, but also voltage levels,
e.g. via performance states.

Use the provided OPP table, to set proper OPP frequency which through
required-opps will trigger performance state change.  This deprecates
the old freq-table-hz Devicetree property and old clock scaling method
in favor of PM core code.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

---

Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

drivers/scsi/ufs/ufshcd-pltfrm.c

@@ -10,6 +10,7 @@
 
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/pm_opp.h>
 #include <linux/pm_runtime.h>
 #include <linux/of.h>
 
@@ -108,6 +109,72 @@ static int ufshcd_parse_clock_info(struct ufs_hba *hba)
 	return ret;
 }
 
+static int ufshcd_parse_operating_points(struct ufs_hba *hba)
+{
+	struct device *dev = hba->dev;
+	struct device_node *np = dev->of_node;
+	struct ufs_clk_info *clki;
+	const char *names[16];
+	int cnt, i, ret;
+
+	if (!of_find_property(dev->of_node, "operating-points-v2", NULL))
+		return 0;
+
+	cnt = of_property_count_strings(np, "clock-names");
+	if (cnt <= 0) {
+		dev_warn(dev, "%s: Missing clock-names\n",
+			 __func__);
+		return -EINVAL;
+	}
+
+	if (cnt > ARRAY_SIZE(names)) {
+		dev_info(dev, "%s: Too many clock-names\n",  __func__);
+		return -EINVAL;
+	}
+
+	if (of_find_property(np, "freq-table-hz", NULL)) {
+		dev_info(dev, "%s: operating-points and freq-table-hz are incompatible\n",
+			 __func__);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < cnt; i++) {
+		ret = of_property_read_string_index(np, "clock-names", i,
+						    &names[i]);
+		if (ret)
+			return ret;
+
+		clki = devm_kzalloc(dev, sizeof(*clki), GFP_KERNEL);
+		if (!clki)
+			return -ENOMEM;
+
+		clki->name = devm_kstrdup(dev, names[i], GFP_KERNEL);
+		if (!clki->name)
+			return -ENOMEM;
+
+		if (!strcmp(names[i], "ref_clk"))
+			clki->keep_link_active = true;
+
+		list_add_tail(&clki->list, &hba->clk_list_head);
+	}
+
+	ret = devm_pm_opp_set_clknames(dev, names, i);
+	if (ret)
+		return ret;
+
+	ret = devm_pm_opp_register_set_opp_helper(dev, ufshcd_set_opp);
+	if (ret)
+		return ret;
+
+	ret = devm_pm_opp_of_add_table(dev);
+	if (ret)
+		return ret;
+
+	hba->use_pm_opp = true;
+
+	return 0;
+}
+
 #define MAX_PROP_SIZE 32
 static int ufshcd_populate_vreg(struct device *dev, const char *name,
 		struct ufs_vreg **out_vreg)
@@ -363,6 +430,12 @@ int ufshcd_pltfrm_init(struct platform_device *pdev,
 		goto dealloc_host;
 	}
 
+	err = ufshcd_parse_operating_points(hba);
+	if (err) {
+		dev_err(dev, "%s: OPP parse failed %d\n", __func__, err);
+		goto dealloc_host;
+	}
+
 	ufshcd_init_lanes_per_dir(hba);
 
 	err = ufshcd_init(hba, mmio_base, irq);