[PATCH 4/5] thermal: khadas_mcu_fan: add support for Khadas Edge 2

[muhammed.efecetin.67@gmail.com]

From: Muhammed Efe Cetin <efectn@protonmail.com>

Fan control on the Khadas Edge 2 is controlled with the 0x8A register,
using percentage values from 0 to 100, whereas there are only 3 constant steps in previous Khadas boards.
Therefore, i added a new cooling-levels property, similar to the one used in the pwm-fan driver.
The original behavior can still be used when the cooling-levels property is not specified,
ensuring that the new functionality does not break old boards.

Signed-off-by: Muhammed Efe Cetin <efectn@protonmail.com>
---
 drivers/thermal/khadas_mcu_fan.c | 76 ++++++++++++++++++++++++++++++--
 1 file changed, 72 insertions(+), 4 deletions(-)

diff --git a/drivers/thermal/khadas_mcu_fan.c b/drivers/thermal/khadas_mcu_fan.c
index d35e5313b..504e7d254 100644
--- a/drivers/thermal/khadas_mcu_fan.c
+++ b/drivers/thermal/khadas_mcu_fan.c
@@ -15,10 +15,16 @@
 #include <linux/thermal.h>
 
 #define MAX_LEVEL 3
+#define MAX_SPEED 0x64
 
 struct khadas_mcu_fan_ctx {
 	struct khadas_mcu *mcu;
 	unsigned int level;
+
+	unsigned int fan_max_level;
+	unsigned int fan_register;
+	unsigned int *fan_cooling_levels;
+
 	struct thermal_cooling_device *cdev;
 };
 
@@ -26,9 +32,21 @@ static int khadas_mcu_fan_set_level(struct khadas_mcu_fan_ctx *ctx,
 				    unsigned int level)
 {
 	int ret;
+	unsigned int write_level = level;
+
+	if (level > ctx->fan_max_level)
+		return -EINVAL;
+
+	if (ctx->fan_cooling_levels != NULL) {
+		write_level = ctx->fan_cooling_levels[level];
+
+		if (write_level > MAX_SPEED)
+			return -EINVAL;
+	}
+
+	ret = regmap_write(ctx->mcu->regmap, ctx->fan_register,
+			   write_level);
 
-	ret = regmap_write(ctx->mcu->regmap, KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG,
-			   level);
 	if (ret)
 		return ret;
 
@@ -40,7 +58,9 @@ static int khadas_mcu_fan_set_level(struct khadas_mcu_fan_ctx *ctx,
 static int khadas_mcu_fan_get_max_state(struct thermal_cooling_device *cdev,
 					unsigned long *state)
 {
-	*state = MAX_LEVEL;
+	struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
+
+	*state = ctx->fan_max_level;
 
 	return 0;
 }
@@ -61,7 +81,7 @@ khadas_mcu_fan_set_cur_state(struct thermal_cooling_device *cdev,
 {
 	struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
 
-	if (state > MAX_LEVEL)
+	if (state > ctx->fan_max_level)
 		return -EINVAL;
 
 	if (state == ctx->level)
@@ -76,6 +96,47 @@ static const struct thermal_cooling_device_ops khadas_mcu_fan_cooling_ops = {
 	.set_cur_state = khadas_mcu_fan_set_cur_state,
 };
 
+static int khadas_mcu_fan_get_cooling_data_edge2(struct khadas_mcu_fan_ctx *ctx, struct device *dev)
+{
+	struct device_node *np = ctx->mcu->dev->of_node;
+	int num, i, ret;
+
+	if (!of_property_present(np, "cooling-levels"))
+		return 0;
+
+	ret = of_property_count_u32_elems(np, "cooling-levels");
+	if (ret <= 0) {
+		dev_err(dev, "Wrong data!\n");
+		return ret ? : -EINVAL;
+	}
+
+	num = ret;
+	ctx->fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
+						   GFP_KERNEL);
+	if (!ctx->fan_cooling_levels)
+		return -ENOMEM;
+
+	ret = of_property_read_u32_array(np, "cooling-levels",
+					 ctx->fan_cooling_levels, num);
+	if (ret) {
+		dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
+		return ret;
+	}
+
+	for (i = 0; i < num; i++) {
+		if (ctx->fan_cooling_levels[i] > MAX_SPEED) {
+			dev_err(dev, "MCU fan state[%d]:%d > %d\n", i,
+				ctx->fan_cooling_levels[i], MAX_SPEED);
+			return -EINVAL;
+		}
+	}
+
+	ctx->fan_max_level = num - 1;
+	ctx->fan_register = KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG_V2;
+
+	return 0;
+}
+
 static int khadas_mcu_fan_probe(struct platform_device *pdev)
 {
 	struct khadas_mcu *mcu = dev_get_drvdata(pdev->dev.parent);
@@ -90,6 +151,13 @@ static int khadas_mcu_fan_probe(struct platform_device *pdev)
 	ctx->mcu = mcu;
 	platform_set_drvdata(pdev, ctx);
 
+	ctx->fan_max_level = MAX_LEVEL;
+	ctx->fan_register = KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG;
+
+	ret = khadas_mcu_fan_get_cooling_data_edge2(ctx, dev);
+	if (ret)
+		return ret;
+
 	cdev = devm_thermal_of_cooling_device_register(dev->parent,
 			dev->parent->of_node, "khadas-mcu-fan", ctx,
 			&khadas_mcu_fan_cooling_ops);
-- 
2.49.0