net: pse-pd: Add new power limit get and set c33 features

This patch add a way to get and set the power limit of a PSE PI.
For that it uses regulator API callbacks wrapper like get_voltage() and
get/set_current_limit() as power is simply V * I.
We used mW unit as defined by the IEEE 802.3-2022 standards.

set_current_limit() uses the voltage return by get_voltage() and the
desired power limit to calculate the current limit. get_voltage() callback
is then mandatory to set the power limit.

get_current_limit() callback is by default looking at a driver callback
and fallback to extracting the current limit from _pse_ethtool_get_status()
if the driver does not set its callback. We prefer let the user the choice
because ethtool_get_status return much more information than the current
limit.

expand pse status with c33_pw_limit_ranges to return the ranges available
to configure the power limit.

Reviewed-by: Sai Krishna <saikrishnag@marvell.com>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://patch.msgid.link/20240704-feature_poe_power_cap-v6-4-320003204264@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/pse-pd/pse_core.c b/drivers/net/pse-pd/pse_core.c
index 795ab264eaf27b79be093845955a6f0cc4c1889f..16f364b3473b2c15050ab6e23d67e6559d93b168 100644 (file)
--- a/drivers/net/pse-pd/pse_core.c
+++ b/drivers/net/pse-pd/pse_core.c
@@ -265,10 +265,113 @@ static int pse_pi_disable(struct regulator_dev *rdev)
        return ret;
 }
 
+static int _pse_pi_get_voltage(struct regulator_dev *rdev)
+{
+       struct pse_controller_dev *pcdev = rdev_get_drvdata(rdev);
+       const struct pse_controller_ops *ops;
+       int id;
+
+       ops = pcdev->ops;
+       if (!ops->pi_get_voltage)
+               return -EOPNOTSUPP;
+
+       id = rdev_get_id(rdev);
+       return ops->pi_get_voltage(pcdev, id);
+}
+
+static int pse_pi_get_voltage(struct regulator_dev *rdev)
+{
+       struct pse_controller_dev *pcdev = rdev_get_drvdata(rdev);
+       int ret;
+
+       mutex_lock(&pcdev->lock);
+       ret = _pse_pi_get_voltage(rdev);
+       mutex_unlock(&pcdev->lock);
+
+       return ret;
+}
+
+static int _pse_ethtool_get_status(struct pse_controller_dev *pcdev,
+                                  int id,
+                                  struct netlink_ext_ack *extack,
+                                  struct pse_control_status *status);
+
+static int pse_pi_get_current_limit(struct regulator_dev *rdev)
+{
+       struct pse_controller_dev *pcdev = rdev_get_drvdata(rdev);
+       const struct pse_controller_ops *ops;
+       struct netlink_ext_ack extack = {};
+       struct pse_control_status st = {};
+       int id, uV, ret;
+       s64 tmp_64;
+
+       ops = pcdev->ops;
+       id = rdev_get_id(rdev);
+       mutex_lock(&pcdev->lock);
+       if (ops->pi_get_current_limit) {
+               ret = ops->pi_get_current_limit(pcdev, id);
+               goto out;
+       }
+
+       /* If pi_get_current_limit() callback not populated get voltage
+        * from pi_get_voltage() and power limit from ethtool_get_status()
+        *  to calculate current limit.
+        */
+       ret = _pse_pi_get_voltage(rdev);
+       if (!ret) {
+               dev_err(pcdev->dev, "Voltage null\n");
+               ret = -ERANGE;
+               goto out;
+       }
+       if (ret < 0)
+               goto out;
+       uV = ret;
+
+       ret = _pse_ethtool_get_status(pcdev, id, &extack, &st);
+       if (ret)
+               goto out;
+
+       if (!st.c33_avail_pw_limit) {
+               ret = -ENODATA;
+               goto out;
+       }
+
+       tmp_64 = st.c33_avail_pw_limit;
+       tmp_64 *= 1000000000ull;
+       /* uA = mW * 1000000000 / uV */
+       ret = DIV_ROUND_CLOSEST_ULL(tmp_64, uV);
+
+out:
+       mutex_unlock(&pcdev->lock);
+       return ret;
+}
+
+static int pse_pi_set_current_limit(struct regulator_dev *rdev, int min_uA,
+                                   int max_uA)
+{
+       struct pse_controller_dev *pcdev = rdev_get_drvdata(rdev);
+       const struct pse_controller_ops *ops;
+       int id, ret;
+
+       ops = pcdev->ops;
+       if (!ops->pi_set_current_limit)
+               return -EOPNOTSUPP;
+
+       id = rdev_get_id(rdev);
+       mutex_lock(&pcdev->lock);
+       ret = ops->pi_set_current_limit(pcdev, id, max_uA);
+       mutex_unlock(&pcdev->lock);
+
+       return ret;
+}
+
 static const struct regulator_ops pse_pi_ops = {
        .is_enabled = pse_pi_is_enabled,
        .enable = pse_pi_enable,
        .disable = pse_pi_disable,
+       .get_voltage = pse_pi_get_voltage,
+       .get_current_limit = pse_pi_get_current_limit,
+       .set_current_limit = pse_pi_set_current_limit,
 };
 
 static int
@@ -298,7 +401,9 @@ devm_pse_pi_regulator_register(struct pse_controller_dev *pcdev,
        rdesc->ops = &pse_pi_ops;
        rdesc->owner = pcdev->owner;
 
-       rinit_data->constraints.valid_ops_mask = REGULATOR_CHANGE_STATUS;
+       rinit_data->constraints.valid_ops_mask = REGULATOR_CHANGE_STATUS |
+                                                REGULATOR_CHANGE_CURRENT;
+       rinit_data->constraints.max_uA = MAX_PI_CURRENT;
        rinit_data->supply_regulator = "vpwr";
 
        rconfig.dev = pcdev->dev;
@@ -626,6 +731,23 @@ out:
 }
 EXPORT_SYMBOL_GPL(of_pse_control_get);
 
+static int _pse_ethtool_get_status(struct pse_controller_dev *pcdev,
+                                  int id,
+                                  struct netlink_ext_ack *extack,
+                                  struct pse_control_status *status)
+{
+       const struct pse_controller_ops *ops;
+
+       ops = pcdev->ops;
+       if (!ops->ethtool_get_status) {
+               NL_SET_ERR_MSG(extack,
+                              "PSE driver does not support status report");
+               return -EOPNOTSUPP;
+       }
+
+       return ops->ethtool_get_status(pcdev, id, extack, status);
+}
+
 /**
  * pse_ethtool_get_status - get status of PSE control
  * @psec: PSE control pointer
@@ -638,19 +760,10 @@ int pse_ethtool_get_status(struct pse_control *psec,
                           struct netlink_ext_ack *extack,
                           struct pse_control_status *status)
 {
-       const struct pse_controller_ops *ops;
        int err;
 
-       ops = psec->pcdev->ops;
-
-       if (!ops->ethtool_get_status) {
-               NL_SET_ERR_MSG(extack,
-                              "PSE driver does not support status report");
-               return -EOPNOTSUPP;
-       }
-
        mutex_lock(&psec->pcdev->lock);
-       err = ops->ethtool_get_status(psec->pcdev, psec->id, extack, status);
+       err = _pse_ethtool_get_status(psec->pcdev, psec->id, extack, status);
        mutex_unlock(&psec->pcdev->lock);
 
        return err;
@@ -732,6 +845,43 @@ int pse_ethtool_set_config(struct pse_control *psec,
 }
 EXPORT_SYMBOL_GPL(pse_ethtool_set_config);
 
+/**
+ * pse_ethtool_set_pw_limit - set PSE control power limit
+ * @psec: PSE control pointer
+ * @extack: extack for reporting useful error messages
+ * @pw_limit: power limit value in mW
+ *
+ * Return: 0 on success and failure value on error
+ */
+int pse_ethtool_set_pw_limit(struct pse_control *psec,
+                            struct netlink_ext_ack *extack,
+                            const unsigned int pw_limit)
+{
+       int uV, uA, ret;
+       s64 tmp_64;
+
+       ret = regulator_get_voltage(psec->ps);
+       if (!ret) {
+               NL_SET_ERR_MSG(extack,
+                              "Can't calculate the current, PSE voltage read is 0");
+               return -ERANGE;
+       }
+       if (ret < 0) {
+               NL_SET_ERR_MSG(extack,
+                              "Error reading PSE voltage");
+               return ret;
+       }
+       uV = ret;
+
+       tmp_64 = pw_limit;
+       tmp_64 *= 1000000000ull;
+       /* uA = mW * 1000000000 / uV */
+       uA = DIV_ROUND_CLOSEST_ULL(tmp_64, uV);
+
+       return regulator_set_current_limit(psec->ps, 0, uA);
+}
+EXPORT_SYMBOL_GPL(pse_ethtool_set_pw_limit);
+
 bool pse_has_podl(struct pse_control *psec)
 {
        return psec->pcdev->types & ETHTOOL_PSE_PODL;

diff --git a/include/linux/pse-pd/pse.h b/include/linux/pse-pd/pse.h
index 38b9308e5e7a276bfb1e65765afe6009d14d7e41..591a53e082e6502a91fc5c217cafbf10b551521a 100644 (file)
--- a/include/linux/pse-pd/pse.h
+++ b/include/linux/pse-pd/pse.h
@@ -9,6 +9,9 @@
 #include <linux/list.h>
 #include <uapi/linux/ethtool.h>
 
+/* Maximum current in uA according to IEEE 802.3-2022 Table 145-1 */
+#define MAX_PI_CURRENT 1920000
+
 struct phy_device;
 struct pse_controller_dev;
 
@@ -41,6 +44,12 @@ struct pse_control_config {
  * @c33_actual_pw: power currently delivered by the PSE in mW
  *     IEEE 802.3-2022 30.9.1.1.23 aPSEActualPower
  * @c33_ext_state_info: extended state information of the PSE
+ * @c33_avail_pw_limit: available power limit of the PSE in mW
+ *     IEEE 802.3-2022 145.2.5.4 pse_avail_pwr
+ * @c33_pw_limit_ranges: supported power limit configuration range. The driver
+ *     is in charge of the memory allocation.
+ * @c33_pw_limit_nb_ranges: number of supported power limit configuration
+ *     ranges
  */
 struct pse_control_status {
        enum ethtool_podl_pse_admin_state podl_admin_state;
@@ -50,6 +59,9 @@ struct pse_control_status {
        u32 c33_pw_class;
        u32 c33_actual_pw;
        struct ethtool_c33_pse_ext_state_info c33_ext_state_info;
+       u32 c33_avail_pw_limit;
+       struct ethtool_c33_pse_pw_limit_range *c33_pw_limit_ranges;
+       u32 c33_pw_limit_nb_ranges;
 };
 
 /**
@@ -61,6 +73,14 @@ struct pse_control_status {
  *                May also return negative errno.
  * @pi_enable: Configure the PSE PI as enabled.
  * @pi_disable: Configure the PSE PI as disabled.
+ * @pi_get_voltage: Return voltage similarly to get_voltage regulator
+ *                 callback.
+ * @pi_get_current_limit: Get the configured current limit similarly to
+ *                       get_current_limit regulator callback.
+ * @pi_set_current_limit: Configure the current limit similarly to
+ *                       set_current_limit regulator callback.
+ *                       Should not return an error in case of MAX_PI_CURRENT
+ *                       current value set.
  */
 struct pse_controller_ops {
        int (*ethtool_get_status)(struct pse_controller_dev *pcdev,
@@ -70,6 +90,11 @@ struct pse_controller_ops {
        int (*pi_is_enabled)(struct pse_controller_dev *pcdev, int id);
        int (*pi_enable)(struct pse_controller_dev *pcdev, int id);
        int (*pi_disable)(struct pse_controller_dev *pcdev, int id);
+       int (*pi_get_voltage)(struct pse_controller_dev *pcdev, int id);
+       int (*pi_get_current_limit)(struct pse_controller_dev *pcdev,
+                                   int id);
+       int (*pi_set_current_limit)(struct pse_controller_dev *pcdev,
+                                   int id, int max_uA);
 };
 
 struct module;
@@ -156,6 +181,11 @@ int pse_ethtool_get_status(struct pse_control *psec,
 int pse_ethtool_set_config(struct pse_control *psec,
                           struct netlink_ext_ack *extack,
                           const struct pse_control_config *config);
+int pse_ethtool_set_pw_limit(struct pse_control *psec,
+                            struct netlink_ext_ack *extack,
+                            const unsigned int pw_limit);
+int pse_ethtool_get_pw_limit(struct pse_control *psec,
+                            struct netlink_ext_ack *extack);
 
 bool pse_has_podl(struct pse_control *psec);
 bool pse_has_c33(struct pse_control *psec);
@@ -185,6 +215,19 @@ static inline int pse_ethtool_set_config(struct pse_control *psec,
        return -EOPNOTSUPP;
 }
 
+static inline int pse_ethtool_set_pw_limit(struct pse_control *psec,
+                                          struct netlink_ext_ack *extack,
+                                          const unsigned int pw_limit)
+{
+       return -EOPNOTSUPP;
+}
+
+static inline int pse_ethtool_get_pw_limit(struct pse_control *psec,
+                                          struct netlink_ext_ack *extack)
+{
+       return -EOPNOTSUPP;
+}
+
 static inline bool pse_has_podl(struct pse_control *psec)
 {
        return false;