[PATCH v3 07/23] thermal: armada: convert driver to syscon register accesses

[Miquel Raynal <miquel.raynal@bootlin.com>]

Until recently, only one register was referenced in MVEBU thermal IP
node. Recent changes added a second entry pointing to another
register right next to it. We cannot know for sure that we will not
have to access other registers. That will be actually the case when
overheat interrupt feature will come, where it will be needed to access
DFX registers in the same area.

This approach is not scalable so instead of adding consinuously memory
areas in the DT (and change the DT bindings, while keeping backward
compatibility), move the thermal node into a wider syscon from which it
will be possible to also configure the thermal interrupt.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/thermal/armada_thermal.c | 197 +++++++++++++++++++++++++--------------
 1 file changed, 128 insertions(+), 69 deletions(-)

diff --git a/drivers/thermal/armada_thermal.c b/drivers/thermal/armada_thermal.c
index 1f9706d96a0d..be346c6afde2 100644
--- a/drivers/thermal/armada_thermal.c
+++ b/drivers/thermal/armada_thermal.c
@@ -24,6 +24,8 @@
 #include <linux/of_device.h>
 #include <linux/thermal.h>
 #include <linux/iopoll.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
 
 /* Thermal Manager Control and Status Register */
 #define PMU_TDC0_SW_RST_MASK		(0x1 << 1)
@@ -39,14 +41,6 @@
 #define A375_READOUT_INVERT		BIT(15)
 #define A375_HW_RESETn			BIT(8)
 
-/* Legacy bindings */
-#define LEGACY_CONTROL_MEM_LEN		0x4
-
-/* Current bindings with the 2 control registers under the same memory area */
-#define LEGACY_CONTROL1_OFFSET		0x0
-#define CONTROL0_OFFSET			0x0
-#define CONTROL1_OFFSET			0x4
-
 /* Errata fields */
 #define CONTROL0_TSEN_TC_TRIM_MASK	0x7
 #define CONTROL0_TSEN_TC_TRIM_VAL	0x3
@@ -70,9 +64,7 @@ struct armada_thermal_data;
 
 /* Marvell EBU Thermal Sensor Dev Structure */
 struct armada_thermal_priv {
-	void __iomem *status;
-	void __iomem *control0;
-	void __iomem *control1;
+	struct regmap *syscon;
 	char zone_name[THERMAL_NAME_LENGTH];
 	struct armada_thermal_data *data;
 };
@@ -96,15 +88,20 @@ struct armada_thermal_data {
 	unsigned int temp_shift;
 	unsigned int temp_mask;
 	u32 is_valid_bit;
-	bool needs_control0;
+
+	/* Syscon access */
+	unsigned int syscon_control0_off;
+	unsigned int syscon_control1_off;
+	unsigned int syscon_status_off;
 };
 
 static void armadaxp_init(struct platform_device *pdev,
 			  struct armada_thermal_priv *priv)
 {
+	struct armada_thermal_data *data = priv->data;
 	u32 reg;
 
-	reg = readl_relaxed(priv->control1);
+	regmap_read(priv->syscon, data->syscon_control1_off, &reg);
 	reg |= PMU_TDC0_OTF_CAL_MASK;
 
 	/* Reference calibration value */
@@ -114,29 +111,31 @@ static void armadaxp_init(struct platform_device *pdev,
 	/* Reset the sensor */
 	reg |= PMU_TDC0_SW_RST_MASK;
 
-	writel(reg, priv->control1);
+	regmap_write(priv->syscon, data->syscon_control1_off, reg);
 
 	/* Enable the sensor */
-	reg = readl_relaxed(priv->status);
+	regmap_read(priv->syscon, data->syscon_status_off, &reg);
 	reg &= ~PMU_TM_DISABLE_MASK;
-	writel(reg, priv->status);
+	regmap_write(priv->syscon, data->syscon_status_off, reg);
 }
 
 static void armada370_init(struct platform_device *pdev,
 			   struct armada_thermal_priv *priv)
 {
+	struct armada_thermal_data *data = priv->data;
 	u32 reg;
 
-	reg = readl_relaxed(priv->control1);
+	regmap_read(priv->syscon, data->syscon_control1_off, &reg);
 	reg |= PMU_TDC0_OTF_CAL_MASK;
 
 	/* Reference calibration value */
 	reg &= ~PMU_TDC0_REF_CAL_CNT_MASK;
 	reg |= (0xf1 << PMU_TDC0_REF_CAL_CNT_OFFS);
 
+	/* Reset the sensor */
 	reg &= ~PMU_TDC0_START_CAL_MASK;
 
-	writel(reg, priv->control1);
+	regmap_write(priv->syscon, data->syscon_control1_off, reg);
 
 	msleep(10);
 }
@@ -144,18 +143,20 @@ static void armada370_init(struct platform_device *pdev,
 static void armada375_init(struct platform_device *pdev,
 			   struct armada_thermal_priv *priv)
 {
+	struct armada_thermal_data *data = priv->data;
 	u32 reg;
 
-	reg = readl(priv->control1);
+	regmap_read(priv->syscon, data->syscon_control1_off, &reg);
 	reg &= ~(A375_UNIT_CONTROL_MASK << A375_UNIT_CONTROL_SHIFT);
 	reg &= ~A375_READOUT_INVERT;
 	reg &= ~A375_HW_RESETn;
+	regmap_write(priv->syscon, data->syscon_control1_off, reg);
 
-	writel(reg, priv->control1);
 	msleep(20);
 
 	reg |= A375_HW_RESETn;
-	writel(reg, priv->control1);
+	regmap_write(priv->syscon, data->syscon_control1_off, reg);
+
 	msleep(50);
 }
 
@@ -163,29 +164,29 @@ static void armada_wait_sensor_validity(struct armada_thermal_priv *priv)
 {
 	u32 reg;
 
-	readl_relaxed_poll_timeout(priv->status, reg,
-				   reg & priv->data->is_valid_bit,
-				   STATUS_POLL_PERIOD_US,
-				   STATUS_POLL_TIMEOUT_US);
+	regmap_read_poll_timeout(priv->syscon, priv->data->syscon_status_off,
+				 reg, reg & priv->data->is_valid_bit,
+				 STATUS_POLL_PERIOD_US,
+				 STATUS_POLL_TIMEOUT_US);
 }
 
 static void armada380_init(struct platform_device *pdev,
 			   struct armada_thermal_priv *priv)
 {
-	u32 reg = readl_relaxed(priv->control1);
+	struct armada_thermal_data *data = priv->data;
+	u32 reg;
 
 	/* Disable the HW/SW reset */
+	regmap_read(priv->syscon, data->syscon_control1_off, &reg);
 	reg |= CONTROL1_EXT_TSEN_HW_RESETn;
 	reg &= ~CONTROL1_EXT_TSEN_SW_RESET;
-	writel(reg, priv->control1);
+	regmap_write(priv->syscon, data->syscon_control1_off, reg);
 
 	/* Set Tsen Tc Trim to correct default value (errata #132698) */
-	if (priv->control0) {
-		reg = readl_relaxed(priv->control0);
-		reg &= ~CONTROL0_TSEN_TC_TRIM_MASK;
-		reg |= CONTROL0_TSEN_TC_TRIM_VAL;
-		writel(reg, priv->control0);
-	}
+	regmap_read(priv->syscon, data->syscon_control0_off, &reg);
+	reg &= ~CONTROL0_TSEN_TC_TRIM_MASK;
+	reg |= CONTROL0_TSEN_TC_TRIM_VAL;
+	regmap_write(priv->syscon, data->syscon_control0_off, reg);
 
 	/* Wait the sensors to be valid or the core will warn the user */
 	armada_wait_sensor_validity(priv);
@@ -194,9 +195,10 @@ static void armada380_init(struct platform_device *pdev,
 static void armada_ap806_init(struct platform_device *pdev,
 			      struct armada_thermal_priv *priv)
 {
+	struct armada_thermal_data *data = priv->data;
 	u32 reg;
 
-	reg = readl_relaxed(priv->control0);
+	regmap_read(priv->syscon, data->syscon_control0_off, &reg);
 	reg &= ~CONTROL0_TSEN_RESET;
 	reg |= CONTROL0_TSEN_START | CONTROL0_TSEN_ENABLE;
 
@@ -206,7 +208,7 @@ static void armada_ap806_init(struct platform_device *pdev,
 	/* Enable average (2 samples by default) */
 	reg &= ~CONTROL0_TSEN_AVG_BYPASS;
 
-	writel(reg, priv->control0);
+	regmap_write(priv->syscon, data->syscon_control0_off, reg);
 
 	/* Wait the sensors to be valid or the core will warn the user */
 	armada_wait_sensor_validity(priv);
@@ -215,25 +217,28 @@ static void armada_ap806_init(struct platform_device *pdev,
 static void armada_cp110_init(struct platform_device *pdev,
 			      struct armada_thermal_priv *priv)
 {
+	struct armada_thermal_data *data = priv->data;
 	u32 reg;
 
 	armada380_init(pdev, priv);
 
 	/* Sample every ~2ms */
-	reg = readl_relaxed(priv->control0);
+	regmap_read(priv->syscon, data->syscon_control0_off, &reg);
 	reg |= CONTROL0_TSEN_OSR_MAX << CONTROL0_TSEN_OSR_SHIFT;
-	writel(reg, priv->control0);
+	regmap_write(priv->syscon, data->syscon_control0_off, reg);
 
 	/* Average the output value over 2^1 = 2 samples */
-	reg = readl_relaxed(priv->control1);
+	regmap_read(priv->syscon, data->syscon_control1_off, &reg);
 	reg &= ~CONTROL1_TSEN_AVG_MASK << CONTROL1_TSEN_AVG_SHIFT;
 	reg |= 1 << CONTROL1_TSEN_AVG_SHIFT;
-	writel(reg, priv->control1);
+	regmap_write(priv->syscon, data->syscon_control1_off, reg);
 }
 
 static bool armada_is_valid(struct armada_thermal_priv *priv)
 {
-	u32 reg = readl_relaxed(priv->status);
+	u32 reg;
+
+	regmap_read(priv->syscon, priv->data->syscon_status_off, &reg);
 
 	return reg & priv->data->is_valid_bit;
 }
@@ -252,7 +257,7 @@ static int armada_get_temp(struct thermal_zone_device *thermal,
 		return -EIO;
 	}
 
-	reg = readl_relaxed(priv->status);
+	regmap_read(priv->syscon, priv->data->syscon_status_off, &reg);
 	reg = (reg >> priv->data->temp_shift) & priv->data->temp_mask;
 	if (priv->data->signed_sample)
 		/* The most significant bit is the sign bit */
@@ -284,6 +289,8 @@ static const struct armada_thermal_data armadaxp_data = {
 	.coef_b = 3153000000ULL,
 	.coef_m = 10000000ULL,
 	.coef_div = 13825,
+	.syscon_status_off = 0xb0,
+	.syscon_control1_off = 0xd0,
 };
 
 static const struct armada_thermal_data armada370_data = {
@@ -295,6 +302,8 @@ static const struct armada_thermal_data armada370_data = {
 	.coef_b = 3153000000ULL,
 	.coef_m = 10000000ULL,
 	.coef_div = 13825,
+	.syscon_status_off = 0x0,
+	.syscon_control1_off = 0x4,
 };
 
 static const struct armada_thermal_data armada375_data = {
@@ -306,7 +315,9 @@ static const struct armada_thermal_data armada375_data = {
 	.coef_b = 3171900000ULL,
 	.coef_m = 10000000ULL,
 	.coef_div = 13616,
-	.needs_control0 = true,
+	.syscon_status_off = 0x78,
+	.syscon_control0_off = 0x7c,
+	.syscon_control1_off = 0x80,
 };
 
 static const struct armada_thermal_data armada380_data = {
@@ -319,6 +330,9 @@ static const struct armada_thermal_data armada380_data = {
 	.coef_m = 2000096ULL,
 	.coef_div = 4201,
 	.inverted = true,
+	.syscon_control0_off = 0x70,
+	.syscon_control1_off = 0x74,
+	.syscon_status_off = 0x78,
 };
 
 static const struct armada_thermal_data armada_ap806_data = {
@@ -332,7 +346,9 @@ static const struct armada_thermal_data armada_ap806_data = {
 	.coef_div = 1,
 	.inverted = true,
 	.signed_sample = true,
-	.needs_control0 = true,
+	.syscon_control0_off = 0x84,
+	.syscon_control1_off = 0x88,
+	.syscon_status_off = 0x8C,
 };
 
 static const struct armada_thermal_data armada_cp110_data = {
@@ -345,7 +361,9 @@ static const struct armada_thermal_data armada_cp110_data = {
 	.coef_m = 2000096ULL,
 	.coef_div = 4201,
 	.inverted = true,
-	.needs_control0 = true,
+	.syscon_control0_off = 0x70,
+	.syscon_control1_off = 0x74,
+	.syscon_status_off = 0x78,
 };
 
 static const struct of_device_id armada_thermal_id_table[] = {
@@ -379,6 +397,57 @@ static const struct of_device_id armada_thermal_id_table[] = {
 };
 MODULE_DEVICE_TABLE(of, armada_thermal_id_table);
 
+static const struct regmap_config armada_thermal_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+	.fast_io = true,
+};
+
+static int armada_thermal_probe_legacy(struct platform_device *pdev,
+				       struct armada_thermal_priv *priv)
+{
+	struct armada_thermal_data *data = priv->data;
+	struct resource *res;
+	void __iomem *base;
+
+	/* First memory region points towards the status register */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (IS_ERR(res))
+		return PTR_ERR(res);
+
+	/*
+	 * Edit the resource start address and length to map over all the
+	 * registers, instead of pointing at them one by one.
+	 */
+	res->start -= data->syscon_status_off;
+	res->end = res->start + max(data->syscon_status_off,
+				    max(data->syscon_control0_off,
+					data->syscon_control1_off)) +
+		   sizeof(unsigned int) - 1;
+
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	priv->syscon = devm_regmap_init_mmio(&pdev->dev, base,
+					     &armada_thermal_regmap_config);
+	if (IS_ERR(priv->syscon))
+		return PTR_ERR(priv->syscon);
+
+	return 0;
+}
+
+static int armada_thermal_probe_syscon(struct platform_device *pdev,
+				       struct armada_thermal_priv *priv)
+{
+	priv->syscon = syscon_node_to_regmap(pdev->dev.parent->of_node);
+	if (IS_ERR(priv->syscon))
+		return PTR_ERR(priv->syscon);
+
+	return 0;
+}
+
 static void armada_set_sane_name(struct platform_device *pdev,
 				 struct armada_thermal_priv *priv)
 {
@@ -411,11 +480,10 @@ static void armada_set_sane_name(struct platform_device *pdev,
 
 static int armada_thermal_probe(struct platform_device *pdev)
 {
-	void __iomem *control = NULL;
 	struct thermal_zone_device *thermal;
 	const struct of_device_id *match;
 	struct armada_thermal_priv *priv;
-	struct resource *res;
+	int ret;
 
 	match = of_match_device(armada_thermal_id_table, &pdev->dev);
 	if (!match)
@@ -425,16 +493,6 @@ static int armada_thermal_probe(struct platform_device *pdev)
 	if (!priv)
 		return -ENOMEM;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	priv->status = devm_ioremap_resource(&pdev->dev, res);
-	if (IS_ERR(priv->status))
-		return PTR_ERR(priv->status);
-
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
-	control = devm_ioremap_resource(&pdev->dev, res);
-	if (IS_ERR(control))
-		return PTR_ERR(control);
-
 	priv->data = (struct armada_thermal_data *)match->data;
 
 	/* Ensure device name is correct for the thermal core */
@@ -442,22 +500,23 @@ static int armada_thermal_probe(struct platform_device *pdev)
 
 	/*
 	 * Legacy DT bindings only described "control1" register (also referred
-	 * as "control MSB" on old documentation). New bindings cover
+	 * as "control MSB" on old documentation). Then, bindings moved to cover
 	 * "control0/control LSB" and "control1/control MSB" registers within
-	 * the same resource, which is then of size 8 instead of 4.
+	 * the same resource, which was then of size 8 instead of 4.
+	 *
+	 * The logic of defining sporadic registers is broken. For instance, it
+	 * blocked the addition of the overheat interrupt feature that needed
+	 * another resource somewhere else in the same memory area. One solution
+	 * is to define an overall system controller and put the thermal node
+	 * into it, which requires the use of regmaps across all the driver.
 	 */
-	if (resource_size(res) == LEGACY_CONTROL_MEM_LEN) {
-		/* ->control0 unavailable in this configuration */
-		if (priv->data->needs_control0) {
-			dev_err(&pdev->dev, "No access to control0 register\n");
-			return -EINVAL;
-		}
+	if (IS_ERR(syscon_node_to_regmap(pdev->dev.parent->of_node)))
+		ret = armada_thermal_probe_legacy(pdev, priv);
+	else
+		ret = armada_thermal_probe_syscon(pdev, priv);
 
-		priv->control1 = control + LEGACY_CONTROL1_OFFSET;
-	} else {
-		priv->control0 = control + CONTROL0_OFFSET;
-		priv->control1 = control + CONTROL1_OFFSET;
-	}
+	if (ret)
+		return ret;
 
 	priv->data->init(pdev, priv);
 
-- 
2.14.1