PM: AVS: qcom-cpr: Use nvmem_cell_read_variable_le_u32()

Let's delete the private function cpr_read_efuse() since it does the
basically the same thing as the new API call
nvmem_cell_read_variable_le_u32().

Differences between the new API call and the old private function:
* less error printing (I assume this is OK).
* will give an error if the value doesn't fit in 32-bits (the old code
  would have truncated silently).

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Niklas Cassel <nks@flawful.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20210521134437.v2.1.Id1c70158722750aec0673d60c12e46a9c66bbfed@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Author: dianders

drivers/soc/qcom/cpr.c

@@ -801,38 +801,6 @@ static int cpr_set_performance_state(struct generic_pm_domain *domain,
 	return ret;
 }
 
-static int cpr_read_efuse(struct device *dev, const char *cname, u32 *data)
-{
-	struct nvmem_cell *cell;
-	ssize_t len;
-	char *ret;
-	int i;
-
-	*data = 0;
-
-	cell = nvmem_cell_get(dev, cname);
-	if (IS_ERR(cell)) {
-		if (PTR_ERR(cell) != -EPROBE_DEFER)
-			dev_err(dev, "undefined cell %s\n", cname);
-		return PTR_ERR(cell);
-	}
-
-	ret = nvmem_cell_read(cell, &len);
-	nvmem_cell_put(cell);
-	if (IS_ERR(ret)) {
-		dev_err(dev, "can't read cell %s\n", cname);
-		return PTR_ERR(ret);
-	}
-
-	for (i = 0; i < len; i++)
-		*data |= ret[i] << (8 * i);
-
-	kfree(ret);
-	dev_dbg(dev, "efuse read(%s) = %x, bytes %zd\n", cname, *data, len);
-
-	return 0;
-}
-
 static int
 cpr_populate_ring_osc_idx(struct cpr_drv *drv)
 {
@@ -843,8 +811,7 @@ cpr_populate_ring_osc_idx(struct cpr_drv *drv)
 	int ret;
 
 	for (; fuse < end; fuse++, fuses++) {
-		ret = cpr_read_efuse(drv->dev, fuses->ring_osc,
-				     &data);
+		ret = nvmem_cell_read_variable_le_u32(drv->dev, fuses->ring_osc, &data);
 		if (ret)
 			return ret;
 		fuse->ring_osc_idx = data;
@@ -863,7 +830,7 @@ static int cpr_read_fuse_uV(const struct cpr_desc *desc,
 	u32 bits = 0;
 	int ret;
 
-	ret = cpr_read_efuse(drv->dev, init_v_efuse, &bits);
+	ret = nvmem_cell_read_variable_le_u32(drv->dev, init_v_efuse, &bits);
 	if (ret)
 		return ret;
 
@@ -932,7 +899,7 @@ static int cpr_fuse_corner_init(struct cpr_drv *drv)
 		}
 
 		/* Populate target quotient by scaling */
-		ret = cpr_read_efuse(drv->dev, fuses->quotient, &fuse->quot);
+		ret = nvmem_cell_read_variable_le_u32(drv->dev, fuses->quotient, &fuse->quot);
 		if (ret)
 			return ret;
 
@@ -1001,7 +968,7 @@ static int cpr_calculate_scaling(const char *quot_offset,
 	prev_fuse = fuse - 1;
 
 	if (quot_offset) {
-		ret = cpr_read_efuse(drv->dev, quot_offset, &quot_diff);
+		ret = nvmem_cell_read_variable_le_u32(drv->dev, quot_offset, &quot_diff);
 		if (ret)
 			return ret;
 
@@ -1701,7 +1668,7 @@ static int cpr_probe(struct platform_device *pdev)
 	 * initialized after attaching to the power domain,
 	 * since it depends on the CPU's OPP table.
 	 */
-	ret = cpr_read_efuse(dev, "cpr_fuse_revision", &cpr_rev);
+	ret = nvmem_cell_read_variable_le_u32(dev, "cpr_fuse_revision", &cpr_rev);
 	if (ret)
 		return ret;