regulator: add QCOM RPMh regulator driver

Introduce bindings for RPMh regulator devices found on some Qualcomm Technlogies, Inc. SoCs. These devices allow a given processor within the SoC to make PMIC regulator requests which are aggregated within the RPMh hardware block along with requests from other processors in the SoC to determine the final PMIC regulator hardware state.

Signed-off-by David Collins <[email protected]>

Reviewed-by Rob Herring <[email protected]>

---
 .../bindings/regulator/qcom,rpmh-regulator.txt     | 160 +++++++++++++++++++++
 .../dt-bindings/regulator/qcom,rpmh-regulator.h    |  36 +++++
 2 files changed, 196 insertions(+)

Add the QCOM RPMh regulator driver to manage PMIC regulators which are controlled via RPMh on some Qualcomm Technologies, Inc. SoCs. RPMh is a hardware block which contains several accelerators which are used to manage various hardware resources that are shared between the processors of the SoC. The final hardware state of a regulator is determined within RPMh by performing max aggregation of the requests made by all of the processors.

Add support for PMIC regulator control via the voltage regulator manager (VRM) and oscillator buffer (XOB) RPMh accelerators. VRM supports manipulation of enable state, voltage, and mode. XOB supports manipulation of enable state.

Signed-off-by David Collins <[email protected]>

---
 drivers/regulator/Kconfig               |   9 +
 drivers/regulator/Makefile              |   1 +
 drivers/regulator/qcom-rpmh-regulator.c | 767 ++++++++++++++++++++++++++++++++
 3 files changed, 777 insertions(+)

Add the QCOM RPMh regulator driver to manage PMIC regulators which are controlled via RPMh on some Qualcomm Technologies, Inc. SoCs. RPMh is a hardware block which contains several accelerators which are used to manage various hardware resources that are shared between the processors of the SoC. The final hardware state of a regulator is determined within RPMh by performing max aggregation of the requests made by all of the processors.

Add support for PMIC regulator control via the voltage regulator manager (VRM) and oscillator buffer (XOB) RPMh accelerators. VRM supports manipulation of enable state, voltage, and mode. XOB supports manipulation of enable state.

Signed-off-by David Collins <[email protected]>

---
 drivers/regulator/Kconfig               |   9 +
 drivers/regulator/Makefile              |   1 +
 drivers/regulator/qcom-rpmh-regulator.c | 767 ++++++++++++++++++++++++++++++++
 3 files changed, 777 insertions(+)
 create mode 100644 drivers/regulator/qcom-rpmh-regulator.c

...

drivers/regulator/qcom-rpmh-regulator.c new file +0 -0

new file mode 100644
index 0000000..a7fffb6
 
...

static int rpmh_regulator_send_request(struct rpmh_vreg *vreg,
+ struct tcs_cmd *cmd, int count, bool wait_for_ack)

...

drivers/regulator/qcom-rpmh-regulator.c new file +8 -0

+static int _rpmh_regulator_vrm_set_voltage_sel(struct regulator_dev *rdev,
+				unsigned int selector, bool wait_for_ack)
+{
+	struct rpmh_vreg *vreg = rdev_get_drvdata(rdev);
+	struct tcs_cmd cmd = {
+		.addr = vreg->addr + RPMH_REGULATOR_REG_VRM_VOLTAGE,
+	};
+	int ret;

drivers/regulator/qcom-rpmh-regulator.c new file +37 -0

+static int rpmh_regulator_enable(struct regulator_dev *rdev)
+{
+	struct rpmh_vreg *vreg = rdev_get_drvdata(rdev);
+	struct tcs_cmd cmd = {
+		.addr = vreg->addr + RPMH_REGULATOR_REG_ENABLE,
+		.data = 1,
+	};
+	int ret;
+
+	if (vreg->enabled == -EINVAL &&
+	    vreg->voltage_selector != -ENOTRECOVERABLE) {
+		ret = _rpmh_regulator_vrm_set_voltage_sel(rdev,
+						vreg->voltage_selector, true);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = rpmh_regulator_send_request(vreg, &cmd, 1, true);
+	if (!ret)
+		vreg->enabled = true;
+
+	return ret;
+}
+
+static int rpmh_regulator_disable(struct regulator_dev *rdev)
+{
+	struct rpmh_vreg *vreg = rdev_get_drvdata(rdev);
+	struct tcs_cmd cmd = {
+		.addr = vreg->addr + RPMH_REGULATOR_REG_ENABLE,
+		.data = 0,
+	};
+	int ret;
+
+	if (vreg->enabled == -EINVAL &&
+	    vreg->voltage_selector != -ENOTRECOVERABLE) {
+		ret = _rpmh_regulator_vrm_set_voltage_sel(rdev,
+						vreg->voltage_selector, true);

drivers/regulator/qcom-rpmh-regulator.c new file +18 -0

+/**
+ * rpmh_regulator_init_vreg() - initialize all attributes of an rpmh-regulator
+ * vreg:		Pointer to the individual rpmh-regulator resource
+ * dev:			Pointer to the top level rpmh-regulator PMIC device
+ * node:		Pointer to the individual rpmh-regulator resource
+ *			device node
+ * pmic_id:		String used to identify the top level rpmh-regulator
+ *			PMIC device on the board
+ * rpmh_data:		Pointer to a null-terminated array of rpmh-regulator
+ *			resources defined for the top level PMIC device
+ *
+ * Return: 0 on success, errno on failure
+ */
+static int rpmh_regulator_init_vreg(struct rpmh_vreg *vreg, struct device *dev,
+				struct device_node *node, const char *pmic_id,
+				const struct rpmh_vreg_init_data *rpmh_data)
+{
+	struct regulator_config reg_config = {};

Quoted 3 lines · David Collins

static int rpmh_regulator_send_request(struct rpmh_vreg *vreg,
+ struct tcs_cmd *cmd, int count, bool wait_for_ack)

nit: as of now this is only called with a single command. If you anticipate that this is unlikely to change consider removing 'count', not having it in the calls slightly improves readability.

Quoted 12 lines

drivers/regulator/qcom-rpmh-regulator.c new file +12 -0

+static int _rpmh_regulator_vrm_set_voltage_sel(struct regulator_dev *rdev,
+				unsigned int selector, bool wait_for_ack)
+{
+	struct rpmh_vreg *vreg = rdev_get_drvdata(rdev);
+	struct tcs_cmd cmd = {
+		.addr = vreg->addr + RPMH_REGULATOR_REG_VRM_VOLTAGE,
+	};
+	int ret;
+
+	/* VRM voltage control register is set with voltage in millivolts. */
+	cmd.data = DIV_ROUND_UP(regulator_list_voltage_linear_range(rdev,
+							selector), 1000);

drivers/regulator/qcom-rpmh-regulator.c line 181

Quoted 6 lines

drivers/regulator/qcom-rpmh-regulator.c new file +6 -0

+
+	ret = rpmh_regulator_send_request(vreg, &cmd, 1, wait_for_ack);
+	if (!ret)
+		vreg->voltage_selector = selector;
+
+	return 0;

Shouldn't this return 'ret'?

Quoted 43 lines

drivers/regulator/qcom-rpmh-regulator.c new file +43 -0

+static int rpmh_regulator_enable(struct regulator_dev *rdev)
+{
+	struct rpmh_vreg *vreg = rdev_get_drvdata(rdev);
+	struct tcs_cmd cmd = {
+		.addr = vreg->addr + RPMH_REGULATOR_REG_ENABLE,
+		.data = 1,
+	};
+	int ret;
+
+	if (vreg->enabled == -EINVAL &&
+	    vreg->voltage_selector != -ENOTRECOVERABLE) {
+		ret = _rpmh_regulator_vrm_set_voltage_sel(rdev,
+						vreg->voltage_selector, true);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = rpmh_regulator_send_request(vreg, &cmd, 1, true);
+	if (!ret)
+		vreg->enabled = true;
+
+	return ret;
+}
+
+static int rpmh_regulator_disable(struct regulator_dev *rdev)
+{
+	struct rpmh_vreg *vreg = rdev_get_drvdata(rdev);
+	struct tcs_cmd cmd = {
+		.addr = vreg->addr + RPMH_REGULATOR_REG_ENABLE,
+		.data = 0,
+	};
+	int ret;
+
+	if (vreg->enabled == -EINVAL &&
+	    vreg->voltage_selector != -ENOTRECOVERABLE) {
+		ret = _rpmh_regulator_vrm_set_voltage_sel(rdev,
+						vreg->voltage_selector, true);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = rpmh_regulator_send_request(vreg, &cmd, 1, false);
+	if (!ret)

drivers/regulator/qcom-rpmh-regulator.c line 262

Quoted 4 lines

drivers/regulator/qcom-rpmh-regulator.c new file +4 -0

+		vreg->enabled = false;
+
+	return ret;
+}

nit: rpmh_regulator_enable() and rpmh_regulator_disable() are essentially the same code, consider introducing a helper like _rpmh_regulator_enable(struct regulator_dev *rdev, bool enable).

Quoted 10 lines

drivers/regulator/qcom-rpmh-regulator.c new file +10 -0

+static int rpmh_regulator_init_vreg(struct rpmh_vreg *vreg, struct device *dev,
+				struct device_node *node, const char *pmic_id,
+				const struct rpmh_vreg_init_data *rpmh_data)
+{
+	struct regulator_config reg_config = {};
+	char rpmh_resource_name[20] = "";
+	struct regulator_dev *rdev;
+	struct regulator_init_data *init_data;
+	int ret;
+

drivers/regulator/qcom-rpmh-regulator.c line 426

Quoted 5 lines

drivers/regulator/qcom-rpmh-regulator.c new file +5 -0

+	vreg->dev = dev;
+
+	for (; rpmh_data->name; rpmh_data++)
+		if (!strcmp(rpmh_data->name, node->name))
+			break;

nit: it's a bit odd to use the parameter itself for iteration, but I guess it's a matter of preferences.