iio: adc: sc27xx: refactor some functions for support more PMiCs

Refactor the common adc_nvmem_cell_calib_data,adc_to_volt and call
these in the origin sc27xx_adc_scale_calibration,sc27xx_adc_to_volt
Signed-off-by: Cixi Geng <cixi.geng1@unisoc.com>
Link: https://lore.kernel.org/r/20220419142458.884933-6-gengcixi@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/sc27xx_adc.c

@@ -135,16 +135,41 @@ static int sc27xx_adc_get_calib_data(u32 calib_data, int calib_adc)
 	return ((calib_data & 0xff) + calib_adc - 128) * 4;
 }
 
+/* get the adc nvmem cell calibration data */
+static int adc_nvmem_cell_calib_data(struct sc27xx_adc_data *data, const char *cell_name)
+{
+	struct nvmem_cell *cell;
+	void *buf;
+	u32 origin_calib_data = 0;
+	size_t len;
+
+	if (!data)
+		return -EINVAL;
+
+	cell = nvmem_cell_get(data->dev, cell_name);
+	if (IS_ERR(cell))
+		return PTR_ERR(cell);
+
+	buf = nvmem_cell_read(cell, &len);
+	if (IS_ERR(buf)) {
+		nvmem_cell_put(cell);
+		return PTR_ERR(buf);
+	}
+
+	memcpy(&origin_calib_data, buf, min(len, sizeof(u32)));
+
+	kfree(buf);
+	nvmem_cell_put(cell);
+	return origin_calib_data;
+}
+
 static int sc27xx_adc_scale_calibration(struct sc27xx_adc_data *data,
 					bool big_scale)
 {
 	const struct sc27xx_adc_linear_graph *calib_graph;
 	struct sc27xx_adc_linear_graph *graph;
-	struct nvmem_cell *cell;
 	const char *cell_name;
 	u32 calib_data = 0;
-	void *buf;
-	size_t len;
 
 	if (big_scale) {
 		calib_graph = data->var_data->bscale_cal;
@@ -156,24 +181,13 @@ static int sc27xx_adc_scale_calibration(struct sc27xx_adc_data *data,
 		cell_name = "small_scale_calib";
 	}
 
-	cell = nvmem_cell_get(data->dev, cell_name);
-	if (IS_ERR(cell))
-		return PTR_ERR(cell);
-
-	buf = nvmem_cell_read(cell, &len);
-	nvmem_cell_put(cell);
-
-	if (IS_ERR(buf))
-		return PTR_ERR(buf);
-
-	memcpy(&calib_data, buf, min(len, sizeof(u32)));
+	calib_data = adc_nvmem_cell_calib_data(data, cell_name);
 
 	/* Only need to calibrate the adc values in the linear graph. */
 	graph->adc0 = sc27xx_adc_get_calib_data(calib_data, calib_graph->adc0);
 	graph->adc1 = sc27xx_adc_get_calib_data(calib_data >> 8,
 						calib_graph->adc1);
 
-	kfree(buf);
 	return 0;
 }
 
@@ -309,7 +323,7 @@ static void sc27xx_adc_volt_ratio(struct sc27xx_adc_data *data,
 	*div_denominator = ratio & SC27XX_RATIO_DENOMINATOR_MASK;
 }
 
-static int sc27xx_adc_to_volt(struct sc27xx_adc_linear_graph *graph,
+static int adc_to_volt(struct sc27xx_adc_linear_graph *graph,
 			      int raw_adc)
 {
 	int tmp;
@@ -318,6 +332,16 @@ static int sc27xx_adc_to_volt(struct sc27xx_adc_linear_graph *graph,
 	tmp /= (graph->adc0 - graph->adc1);
 	tmp += graph->volt1;
 
+	return tmp;
+}
+
+static int sc27xx_adc_to_volt(struct sc27xx_adc_linear_graph *graph,
+			      int raw_adc)
+{
+	int tmp;
+
+	tmp = adc_to_volt(graph, raw_adc);
+
 	return tmp < 0 ? 0 : tmp;
 }