[PATCH v3 2/4] phy: qcom-mipi-csi2: Make OPP table optional

[Anusha Arun Nandi <anusha.nandi@oss.qualcomm.com>]

Not every SoC the generic MIPI CSI2 PHY driver supports needs an OPP
table: a CSIPHY with only a single, unscaled power-domain has no
performance state to vote on, so running its "core" clock through
the OPP framework buys nothing over a plain clk_set_rate(). Add a
no_opp flag to struct mipi_csi2phy_soc_cfg and skip
devm_pm_opp_set_clkname()/devm_pm_opp_of_add_table() in probe() and
the OPP/performance-state handling in
phy_qcom_mipi_csi2_set_clock_rates() when it's set, falling back to
clk_round_rate()/clk_set_rate() on the timer clock only.

x1e80100 doesn't set no_opp, so this is a no-op for it. The "core"/
"timer" clock-name strings themselves stay hardcoded literals: every
SoC this driver supports uses the same two names, so there's nothing
to make configurable there.

Reviewed-by: Jigarkumar Zala <jigarkumar.zala@oss.qualcomm.com>
Signed-off-by: Anusha Arun Nandi <anusha.nandi@oss.qualcomm.com>
---
 .../phy/qualcomm/phy-qcom-mipi-csi2-core.c    | 72 ++++++++++---------
 drivers/phy/qualcomm/phy-qcom-mipi-csi2.h     |  3 +
 2 files changed, 42 insertions(+), 33 deletions(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-mipi-csi2-core.c b/drivers/phy/qualcomm/phy-qcom-mipi-csi2-core.c
index 269232499fca..8bebc943a771 100644
--- a/drivers/phy/qualcomm/phy-qcom-mipi-csi2-core.c
+++ b/drivers/phy/qualcomm/phy-qcom-mipi-csi2-core.c
@@ -32,40 +32,43 @@ phy_qcom_mipi_csi2_set_clock_rates(struct mipi_csi2phy_device *csi2phy,
 	unsigned long opp_rate = link_freq / 4;
 	struct dev_pm_opp *opp;
 	long timer_rate;
-	int i, pstate;
+	int i = 0, pstate;
 	int ret;
 
-	opp = dev_pm_opp_find_freq_ceil(dev, &opp_rate);
-	if (IS_ERR(opp)) {
-		dev_err(csi2phy->dev, "Couldn't find ceiling for %lld Hz\n",
-			link_freq);
-		return PTR_ERR(opp);
-	}
+	if (!csi2phy->soc_cfg->no_opp) {
+		opp = dev_pm_opp_find_freq_ceil(dev, &opp_rate);
+		if (IS_ERR(opp)) {
+			dev_err(csi2phy->dev, "Couldn't find ceiling for %lld Hz\n",
+				link_freq);
+			return PTR_ERR(opp);
+		}
 
-	pstate = 0;
-	for (i = 0; csi2phy->pd_list && i < csi2phy->pd_list->num_pds; i++) {
-		unsigned int perf;
+		pstate = 0;
+		for (i = 0; csi2phy->pd_list && i < csi2phy->pd_list->num_pds; i++) {
+			unsigned int perf;
 
-		if (!csi2phy->soc_cfg->genpds[i].scaled)
-			continue;
+			if (!csi2phy->soc_cfg->genpds[i].scaled)
+				continue;
 
-		perf = dev_pm_opp_get_required_pstate(opp, pstate);
-		pstate += 1;
+			perf = dev_pm_opp_get_required_pstate(opp, pstate);
+			pstate += 1;
 
-		ret = dev_pm_genpd_set_performance_state(csi2phy->pd_list->pd_devs[i], perf);
-		if (ret) {
-			dev_err(csi2phy->dev, "Couldn't set perf state %u\n",
-				perf);
-			dev_pm_opp_put(opp);
-			goto unset_pstate;
+			ret = dev_pm_genpd_set_performance_state(csi2phy->pd_list->pd_devs[i],
+								 perf);
+			if (ret) {
+				dev_err(csi2phy->dev, "Couldn't set perf state %u\n",
+					perf);
+				dev_pm_opp_put(opp);
+				goto unset_pstate;
+			}
 		}
-	}
-	dev_pm_opp_put(opp);
+		dev_pm_opp_put(opp);
 
-	ret = dev_pm_opp_set_rate(dev, opp_rate);
-	if (ret) {
-		dev_err(csi2phy->dev, "dev_pm_opp_set_rate() fail\n");
-		goto unset_opp_rate;
+		ret = dev_pm_opp_set_rate(dev, opp_rate);
+		if (ret) {
+			dev_err(csi2phy->dev, "dev_pm_opp_set_rate() fail\n");
+			goto unset_opp_rate;
+		}
 	}
 
 	timer_rate = clk_round_rate(csi2phy->timer_clk, link_freq / 4);
@@ -83,7 +86,8 @@ phy_qcom_mipi_csi2_set_clock_rates(struct mipi_csi2phy_device *csi2phy,
 	return 0;
 
 unset_opp_rate:
-	dev_pm_opp_set_rate(dev, 0);
+	if (!csi2phy->soc_cfg->no_opp)
+		dev_pm_opp_set_rate(dev, 0);
 
 unset_pstate:
 	while (i--) {
@@ -405,13 +409,15 @@ static int phy_qcom_mipi_csi2_probe(struct platform_device *pdev)
 	if (!csi2phy->timer_clk)
 		return dev_err_probe(dev, -ENODEV, "no timer clock\n");
 
-	ret = devm_pm_opp_set_clkname(dev, "core");
-	if (ret)
-		return dev_err_probe(dev, ret, "Failed to set opp clkname\n");
+	if (!csi2phy->soc_cfg->no_opp) {
+		ret = devm_pm_opp_set_clkname(dev, "core");
+		if (ret)
+			return dev_err_probe(dev, ret, "Failed to set opp clkname\n");
 
-	ret = devm_pm_opp_of_add_table(dev);
-	if (ret)
-		return dev_err_probe(dev, ret, "invalid OPP table in device tree\n");
+		ret = devm_pm_opp_of_add_table(dev);
+		if (ret)
+			return dev_err_probe(dev, ret, "invalid OPP table in device tree\n");
+	}
 
 	num_supplies = csi2phy->soc_cfg->num_supplies;
 	csi2phy->supplies = devm_kzalloc(dev, sizeof(*csi2phy->supplies) * num_supplies,
diff --git a/drivers/phy/qualcomm/phy-qcom-mipi-csi2.h b/drivers/phy/qualcomm/phy-qcom-mipi-csi2.h
index 7e55ae007370..6cf9e5b956f7 100644
--- a/drivers/phy/qualcomm/phy-qcom-mipi-csi2.h
+++ b/drivers/phy/qualcomm/phy-qcom-mipi-csi2.h
@@ -68,6 +68,9 @@ struct mipi_csi2phy_soc_cfg {
 	const char ** const clk_names;
 	const unsigned int num_clk;
 
+	/* Skip OPP-based clock/pstate scaling. */
+	const bool no_opp;
+
 	const struct mipi_csi2_genpd *genpds;
 	const unsigned int num_genpds;
 };
-- 
2.34.1