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From: Thomas Richard <thomas.richard@bootlin.com>
To: rafael@kernel.org,
	daniel.lezcano@linaro.org
Cc: rui.zhang@intel.com,
	lukasz.luba@arm.com,
	linux-pm@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	gregory.clement@bootlin.com,
	thomas.petazzoni@bootlin.com,
	theo.lebrun@bootlin.com,
	u-kumar1@ti.com,
	j-keerthy@ti.com,
	Thomas Richard <thomas.richard@bootlin.com>
Subject: [PATCH v4] thermal: k3_j72xx_bandgap: implement suspend/resume support
Date: Thu, 25 Apr 2024 17:32:38 +0200
Message-Id: <20240425153238.498750-1-thomas.richard@bootlin.com>
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From: Théo Lebrun <theo.lebrun@bootlin.com>

This add suspend-to-ram support.

The derived_table is kept-as is, so the resume is only about
pm_runtime_* calls and restoring the same registers as the probe.

Extract the hardware initialization procedure to a function called at
both probe-time & resume-time.

The probe-time loop is split in two to ensure doing the hardware
initialization before registering thermal zones. That ensures our
callbacks cannot be called while in bad state.

The 100ms delay in the hardware initialization sequence was removed.
It was initially added to be sure the thresholds are programmed before
enabling the interrupt, but in fact it's not needed (tested on J7200
platform).

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Acked-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Thomas Richard <thomas.richard@bootlin.com>
---

v4:
 - Remove the 100ms delay in the hardware initialization sequence
v3:
 - Remove __maybe_unused attributes and use the magic of PTR_IF()
v2:
 - Fix warnings/errors reported by kernel test robot

 drivers/thermal/k3_j72xx_bandgap.c | 111 ++++++++++++++++++++---------
 1 file changed, 78 insertions(+), 33 deletions(-)

diff --git a/drivers/thermal/k3_j72xx_bandgap.c b/drivers/thermal/k3_j72xx_bandgap.c
index c74094a86982..9bc279ac131a 100644
--- a/drivers/thermal/k3_j72xx_bandgap.c
+++ b/drivers/thermal/k3_j72xx_bandgap.c
@@ -178,6 +178,7 @@ struct k3_j72xx_bandgap {
 	void __iomem *base;
 	void __iomem *cfg2_base;
 	struct k3_thermal_data *ts_data[K3_VTM_MAX_NUM_TS];
+	int cnt;
 };
 
 /* common data structures */
@@ -338,24 +339,52 @@ static void print_look_up_table(struct device *dev, int *ref_table)
 		dev_dbg(dev, "%d       %d %d\n", i, derived_table[i], ref_table[i]);
 }
 
+static void k3_j72xx_bandgap_init_hw(struct k3_j72xx_bandgap *bgp)
+{
+	struct k3_thermal_data *data;
+	int id, high_max, low_temp;
+	u32 val;
+
+	for (id = 0; id < bgp->cnt; id++) {
+		data = bgp->ts_data[id];
+		val = readl(bgp->cfg2_base + data->ctrl_offset);
+		val |= (K3_VTM_TMPSENS_CTRL_MAXT_OUTRG_EN |
+			K3_VTM_TMPSENS_CTRL_SOC |
+			K3_VTM_TMPSENS_CTRL_CLRZ | BIT(4));
+		writel(val, bgp->cfg2_base + data->ctrl_offset);
+	}
+
+	/*
+	 * Program TSHUT thresholds
+	 * Step 1: set the thresholds to ~123C and 105C WKUP_VTM_MISC_CTRL2
+	 * Step 2: WKUP_VTM_TMPSENS_CTRL_j set the MAXT_OUTRG_EN  bit
+	 *         This is already taken care as per of init
+	 * Step 3: WKUP_VTM_MISC_CTRL set the ANYMAXT_OUTRG_ALERT_EN  bit
+	 */
+	high_max = k3_j72xx_bandgap_temp_to_adc_code(MAX_TEMP);
+	low_temp = k3_j72xx_bandgap_temp_to_adc_code(COOL_DOWN_TEMP);
+
+	writel((low_temp << 16) | high_max, bgp->cfg2_base + K3_VTM_MISC_CTRL2_OFFSET);
+	writel(K3_VTM_ANYMAXT_OUTRG_ALERT_EN, bgp->cfg2_base + K3_VTM_MISC_CTRL_OFFSET);
+}
+
 struct k3_j72xx_bandgap_data {
 	const bool has_errata_i2128;
 };
 
 static int k3_j72xx_bandgap_probe(struct platform_device *pdev)
 {
-	int ret = 0, cnt, val, id;
-	int high_max, low_temp;
-	struct resource *res;
+	const struct k3_j72xx_bandgap_data *driver_data;
+	struct thermal_zone_device *ti_thermal;
 	struct device *dev = &pdev->dev;
+	bool workaround_needed = false;
 	struct k3_j72xx_bandgap *bgp;
 	struct k3_thermal_data *data;
-	bool workaround_needed = false;
-	const struct k3_j72xx_bandgap_data *driver_data;
-	struct thermal_zone_device *ti_thermal;
-	int *ref_table;
 	struct err_values err_vals;
 	void __iomem *fuse_base;
+	int ret = 0, val, id;
+	struct resource *res;
+	int *ref_table;
 
 	const s64 golden_factors[] = {
 		-490019999999999936,
@@ -422,10 +451,10 @@ static int k3_j72xx_bandgap_probe(struct platform_device *pdev)
 
 	/* Get the sensor count in the VTM */
 	val = readl(bgp->base + K3_VTM_DEVINFO_PWR0_OFFSET);
-	cnt = val & K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK;
-	cnt >>= __ffs(K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK);
+	bgp->cnt = val & K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK;
+	bgp->cnt >>= __ffs(K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK);
 
-	data = devm_kcalloc(bgp->dev, cnt, sizeof(*data), GFP_KERNEL);
+	data = devm_kcalloc(bgp->dev, bgp->cnt, sizeof(*data), GFP_KERNEL);
 	if (!data) {
 		ret = -ENOMEM;
 		goto err_alloc;
@@ -449,8 +478,8 @@ static int k3_j72xx_bandgap_probe(struct platform_device *pdev)
 	else
 		init_table(3, ref_table, pvt_wa_factors);
 
-	/* Register the thermal sensors */
-	for (id = 0; id < cnt; id++) {
+	/* Precompute the derived table & fill each thermal sensor struct */
+	for (id = 0; id < bgp->cnt; id++) {
 		data[id].bgp = bgp;
 		data[id].ctrl_offset = K3_VTM_TMPSENS0_CTRL_OFFSET + id * 0x20;
 		data[id].stat_offset = data[id].ctrl_offset +
@@ -470,13 +499,13 @@ static int k3_j72xx_bandgap_probe(struct platform_device *pdev)
 		else if (id == 0 && !workaround_needed)
 			memcpy(derived_table, ref_table, TABLE_SIZE * 4);
 
-		val = readl(data[id].bgp->cfg2_base + data[id].ctrl_offset);
-		val |= (K3_VTM_TMPSENS_CTRL_MAXT_OUTRG_EN |
-			K3_VTM_TMPSENS_CTRL_SOC |
-			K3_VTM_TMPSENS_CTRL_CLRZ | BIT(4));
-		writel(val, data[id].bgp->cfg2_base + data[id].ctrl_offset);
-
 		bgp->ts_data[id] = &data[id];
+	}
+
+	k3_j72xx_bandgap_init_hw(bgp);
+
+	/* Register the thermal sensors */
+	for (id = 0; id < bgp->cnt; id++) {
 		ti_thermal = devm_thermal_of_zone_register(bgp->dev, id, &data[id],
 							   &k3_of_thermal_ops);
 		if (IS_ERR(ti_thermal)) {
@@ -486,21 +515,7 @@ static int k3_j72xx_bandgap_probe(struct platform_device *pdev)
 		}
 	}
 
-	/*
-	 * Program TSHUT thresholds
-	 * Step 1: set the thresholds to ~123C and 105C WKUP_VTM_MISC_CTRL2
-	 * Step 2: WKUP_VTM_TMPSENS_CTRL_j set the MAXT_OUTRG_EN  bit
-	 *         This is already taken care as per of init
-	 * Step 3: WKUP_VTM_MISC_CTRL set the ANYMAXT_OUTRG_ALERT_EN  bit
-	 */
-	high_max = k3_j72xx_bandgap_temp_to_adc_code(MAX_TEMP);
-	low_temp = k3_j72xx_bandgap_temp_to_adc_code(COOL_DOWN_TEMP);
-
-	writel((low_temp << 16) | high_max, data[0].bgp->cfg2_base +
-	       K3_VTM_MISC_CTRL2_OFFSET);
-	mdelay(100);
-	writel(K3_VTM_ANYMAXT_OUTRG_ALERT_EN, data[0].bgp->cfg2_base +
-	       K3_VTM_MISC_CTRL_OFFSET);
+	platform_set_drvdata(pdev, bgp);
 
 	print_look_up_table(dev, ref_table);
 	/*
@@ -527,6 +542,35 @@ static void k3_j72xx_bandgap_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 }
 
+static int k3_j72xx_bandgap_suspend(struct device *dev)
+{
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+	return 0;
+}
+
+static int k3_j72xx_bandgap_resume(struct device *dev)
+{
+	struct k3_j72xx_bandgap *bgp = dev_get_drvdata(dev);
+	int ret;
+
+	pm_runtime_enable(dev);
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(dev);
+		pm_runtime_disable(dev);
+		return ret;
+	}
+
+	k3_j72xx_bandgap_init_hw(bgp);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(k3_j72xx_bandgap_pm_ops,
+				k3_j72xx_bandgap_suspend,
+				k3_j72xx_bandgap_resume);
+
 static const struct k3_j72xx_bandgap_data k3_j72xx_bandgap_j721e_data = {
 	.has_errata_i2128 = true,
 };
@@ -554,6 +598,7 @@ static struct platform_driver k3_j72xx_bandgap_sensor_driver = {
 	.driver = {
 		.name = "k3-j72xx-soc-thermal",
 		.of_match_table	= of_k3_j72xx_bandgap_match,
+		.pm = pm_sleep_ptr(&k3_j72xx_bandgap_pm_ops),
 	},
 };
 
-- 
2.39.2