linux-kernel - [PATCH v3] regulator: qcom_smd: Keep one rpm handle for all vregs

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Date: Tue, 09 Jan 2024 11:04:49 +0100
From: Konrad Dybcio <konrad.dybcio@...aro.org>
To: Bjorn Andersson <andersson@...nel.org>, 
 Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>
Cc: linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Konrad Dybcio <konrad.dybcio@...aro.org>
Subject: [PATCH v3] regulator: qcom_smd: Keep one rpm handle for all vregs

For no apparent reason (as there's just one RPM per SoC), all vregs
currently store a copy of a pointer to smd_rpm. Introduce a single,
global one to save up on space in each definition.

bloat-o-meter reports a slight uptick:

Total: Before=44008, After=44080, chg +0.16%

However the saved n * sizeof(ptr) for every dynamically allocated
regulator quickly makes up for it.

Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
---
Changes in v3:
- Validate that the global pointer didn't change
- Update the bloat-o-meter report
- Link to v2: https://lore.kernel.org/r/20231227-topic-rpm_vreg_cleanup-v2-1-04c79c4f9166@linaro.org
Changes in v2:
- Remove unused function argument from rpm_regulator_init_vreg kerneldoc
- Do NOT add a mutex around the rpm assignment, talked to Dmitry offline
  and we concluded it makes no sense
- Link to v1: https://lore.kernel.org/r/20231227-topic-rpm_vreg_cleanup-v1-1-949da0864ac5@linaro.org
---
 drivers/regulator/qcom_smd-regulator.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/regulator/qcom_smd-regulator.c b/drivers/regulator/qcom_smd-regulator.c
index d1be9568025e..3b7e06b9f5ce 100644
--- a/drivers/regulator/qcom_smd-regulator.c
+++ b/drivers/regulator/qcom_smd-regulator.c
@@ -11,11 +11,10 @@
 #include <linux/regulator/of_regulator.h>
 #include <linux/soc/qcom/smd-rpm.h>
 
+struct qcom_smd_rpm *smd_vreg_rpm;
+
 struct qcom_rpm_reg {
 	struct device *dev;
-
-	struct qcom_smd_rpm *rpm;
-
 	u32 type;
 	u32 id;
 
@@ -70,7 +69,7 @@ static int rpm_reg_write_active(struct qcom_rpm_reg *vreg)
 	if (!reqlen)
 		return 0;
 
-	ret = qcom_rpm_smd_write(vreg->rpm, QCOM_SMD_RPM_ACTIVE_STATE,
+	ret = qcom_rpm_smd_write(smd_vreg_rpm, QCOM_SMD_RPM_ACTIVE_STATE,
 				 vreg->type, vreg->id,
 				 req, sizeof(req[0]) * reqlen);
 	if (!ret) {
@@ -1384,14 +1383,13 @@ MODULE_DEVICE_TABLE(of, rpm_of_match);
  * @dev:		Pointer to the top level qcom_smd-regulator PMIC device
  * @node:		Pointer to the individual qcom_smd-regulator resource
  *			device node
- * @rpm:		Pointer to the rpm bus node
  * @pmic_rpm_data:	Pointer to a null-terminated array of qcom_smd-regulator
  *			resources defined for the top level PMIC device
  *
  * Return: 0 on success, errno on failure
  */
 static int rpm_regulator_init_vreg(struct qcom_rpm_reg *vreg, struct device *dev,
-				   struct device_node *node, struct qcom_smd_rpm *rpm,
+				   struct device_node *node,
 				   const struct rpm_regulator_data *pmic_rpm_data)
 {
 	struct regulator_config config = {};
@@ -1409,7 +1407,6 @@ static int rpm_regulator_init_vreg(struct qcom_rpm_reg *vreg, struct device *dev
 	}
 
 	vreg->dev	= dev;
-	vreg->rpm	= rpm;
 	vreg->type	= rpm_data->type;
 	vreg->id	= rpm_data->id;
 
@@ -1449,6 +1446,11 @@ static int rpm_reg_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
+	if (smd_vreg_rpm && rpm != smd_vreg_rpm)
+		return dev_err_probe(dev, -EINVAL, "RPM mismatch\n");
+
+	smd_vreg_rpm = rpm;
+
 	vreg_data = of_device_get_match_data(dev);
 	if (!vreg_data)
 		return -ENODEV;
@@ -1460,8 +1462,7 @@ static int rpm_reg_probe(struct platform_device *pdev)
 			return -ENOMEM;
 		}
 
-		ret = rpm_regulator_init_vreg(vreg, dev, node, rpm, vreg_data);
-
+		ret = rpm_regulator_init_vreg(vreg, dev, node, vreg_data);
 		if (ret < 0) {
 			of_node_put(node);
 			return ret;

---
base-commit: 0f067394dd3b2af3263339cf7183bdb6ee0ac1f8
change-id: 20240109-rpm_vreg_cleanup-9fdb63e9f25d

Best regards,
-- 
Konrad Dybcio <konrad.dybcio@...aro.org>