[PATCH net-next v4 10/27] net: pse-pd: tps23881: Add support for power limit and measurement features

[Kory Maincent <kory.maincent@bootlin.com>]

From: Kory Maincent (Dent Project) <kory.maincent@bootlin.com>

Expand PSE callbacks to support the newly introduced
pi_get/set_pw_limit() and pi_get_voltage() functions. These callbacks
allow for power limit configuration in the TPS23881 controller.

Additionally, the patch includes the pi_get_pw_class() the
pi_get_actual_pw(), and the pi_get_pw_limit_ranges') callbacks providing
more comprehensive PoE status reporting.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
---

Change in v4:
- Several changes for better readibility and to avoid code duplicate.
- Move on to the new callbacks.

Change in v3:
- NIT change, use tps23881_set_val helper to set the power limit
  register value.
- Add policy varaible internally to being able to reconfigure it after a
  PWOFF call.

Change in v2:
- Use newly introduced helpers.
---
 drivers/net/pse-pd/tps23881.c | 258 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 256 insertions(+), 2 deletions(-)

diff --git a/drivers/net/pse-pd/tps23881.c b/drivers/net/pse-pd/tps23881.c
index 340d70ee37fe..5e9dda2c0eac 100644
--- a/drivers/net/pse-pd/tps23881.c
+++ b/drivers/net/pse-pd/tps23881.c
@@ -25,20 +25,32 @@
 #define TPS23881_REG_GEN_MASK	0x17
 #define TPS23881_REG_NBITACC	BIT(5)
 #define TPS23881_REG_PW_EN	0x19
+#define TPS23881_REG_2PAIR_POL1	0x1e
 #define TPS23881_REG_PORT_MAP	0x26
 #define TPS23881_REG_PORT_POWER	0x29
-#define TPS23881_REG_POEPLUS	0x40
+#define TPS23881_REG_4PAIR_POL1	0x2a
+#define TPS23881_REG_INPUT_V	0x2e
+#define TPS23881_REG_CHAN1_A	0x30
+#define TPS23881_REG_CHAN1_V	0x32
+#define TPS23881_REG_FOLDBACK	0x40
 #define TPS23881_REG_TPON	BIT(0)
 #define TPS23881_REG_FWREV	0x41
 #define TPS23881_REG_DEVID	0x43
 #define TPS23881_REG_DEVID_MASK	0xF0
 #define TPS23881_DEVICE_ID	0x02
+#define TPS23881_REG_CHAN1_CLASS	0x4c
 #define TPS23881_REG_SRAM_CTRL	0x60
 #define TPS23881_REG_SRAM_DATA	0x61
 
+#define TPS23881_UV_STEP	3662
+#define TPS23881_NA_STEP	70190
+#define TPS23881_MW_STEP	500
+#define TPS23881_MIN_PI_PW_LIMIT_MW	2000
+
 struct tps23881_port_desc {
 	u8 chan[2];
 	bool is_4p;
+	int pw_pol;
 };
 
 struct tps23881_priv {
@@ -102,6 +114,54 @@ static u16 tps23881_set_val(u16 reg_val, u8 chan, u8 field_offset,
 	return reg_val;
 }
 
+static int
+tps23881_pi_set_pw_pol_limit(struct tps23881_priv *priv, int id, u8 pw_pol,
+			     bool is_4p)
+{
+	struct i2c_client *client = priv->client;
+	int ret, reg;
+	u16 val;
+	u8 chan;
+
+	chan = priv->port[id].chan[0];
+	if (!is_4p) {
+		reg = TPS23881_REG_2PAIR_POL1 + (chan % 4);
+	} else {
+		/* One chan is enough to configure the 4p PI power limit */
+		if ((chan % 4) < 2)
+			reg = TPS23881_REG_4PAIR_POL1;
+		else
+			reg = TPS23881_REG_4PAIR_POL1 + 1;
+	}
+
+	ret = i2c_smbus_read_word_data(client, reg);
+	if (ret < 0)
+		return ret;
+
+	val = tps23881_set_val(ret, chan, 0, 0xff, pw_pol);
+	return i2c_smbus_write_word_data(client, reg, val);
+}
+
+static int tps23881_pi_enable_manual_pol(struct tps23881_priv *priv, int id)
+{
+	struct i2c_client *client = priv->client;
+	int ret;
+	u8 chan;
+	u16 val;
+
+	ret = i2c_smbus_read_byte_data(client, TPS23881_REG_FOLDBACK);
+	if (ret < 0)
+		return ret;
+
+	/* No need to test if the chan is PoE4 as setting either bit for a
+	 * 4P configured port disables the automatic configuration on both
+	 * channels.
+	 */
+	chan = priv->port[id].chan[0];
+	val = tps23881_set_val(ret, chan, 0, BIT(chan % 4), BIT(chan % 4));
+	return i2c_smbus_write_byte_data(client, TPS23881_REG_FOLDBACK, val);
+}
+
 static int tps23881_pi_enable(struct pse_controller_dev *pcdev, int id)
 {
 	struct tps23881_priv *priv = to_tps23881_priv(pcdev);
@@ -171,7 +231,21 @@ static int tps23881_pi_disable(struct pse_controller_dev *pcdev, int id)
 				       BIT(chan % 4));
 	}
 
-	return i2c_smbus_write_word_data(client, TPS23881_REG_DET_CLA_EN, val);
+	ret = i2c_smbus_write_word_data(client, TPS23881_REG_DET_CLA_EN, val);
+	if (ret)
+		return ret;
+
+	/* No power policy */
+	if (priv->port[id].pw_pol < 0)
+		return 0;
+
+	ret = tps23881_pi_enable_manual_pol(priv, id);
+	if (ret < 0)
+		return ret;
+
+	/* Set power policy */
+	return tps23881_pi_set_pw_pol_limit(priv, id, priv->port[id].pw_pol,
+					    priv->port[id].is_4p);
 }
 
 static int
@@ -246,6 +320,177 @@ tps23881_pi_get_pw_status(struct pse_controller_dev *pcdev, int id,
 	return 0;
 }
 
+static int tps23881_pi_get_voltage(struct pse_controller_dev *pcdev, int id)
+{
+	struct tps23881_priv *priv = to_tps23881_priv(pcdev);
+	struct i2c_client *client = priv->client;
+	int ret;
+	u64 uV;
+
+	ret = i2c_smbus_read_word_data(client, TPS23881_REG_INPUT_V);
+	if (ret < 0)
+		return ret;
+
+	uV = ret & 0x3fff;
+	uV *= TPS23881_UV_STEP;
+
+	return (int)uV;
+}
+
+static int
+tps23881_pi_get_chan_current(struct tps23881_priv *priv, u8 chan)
+{
+	struct i2c_client *client = priv->client;
+	int reg, ret;
+	u64 tmp_64;
+
+	/* Registers 0x30 to 0x3d */
+	reg = TPS23881_REG_CHAN1_A + (chan % 4) * 4 + (chan >= 4);
+	ret = i2c_smbus_read_word_data(client, reg);
+	if (ret < 0)
+		return ret;
+
+	tmp_64 = ret & 0x3fff;
+	tmp_64 *= TPS23881_NA_STEP;
+	/* uA = nA / 1000 */
+	tmp_64 = DIV_ROUND_CLOSEST_ULL(tmp_64, 1000);
+	return (int)tmp_64;
+}
+
+static int tps23881_pi_get_pw_class(struct pse_controller_dev *pcdev,
+				    int id)
+{
+	struct tps23881_priv *priv = to_tps23881_priv(pcdev);
+	struct i2c_client *client = priv->client;
+	int ret, reg;
+	u8 chan;
+
+	chan = priv->port[id].chan[0];
+	reg = TPS23881_REG_CHAN1_CLASS + (chan % 4);
+	ret = i2c_smbus_read_word_data(client, reg);
+	if (ret < 0)
+		return ret;
+
+	return tps23881_calc_val(ret, chan, 4, 0x0f);
+}
+
+static int
+tps23881_pi_get_actual_pw(struct pse_controller_dev *pcdev, int id)
+{
+	struct tps23881_priv *priv = to_tps23881_priv(pcdev);
+	int ret, uV, uA;
+	u64 tmp_64;
+	u8 chan;
+
+	ret = tps23881_pi_get_voltage(&priv->pcdev, id);
+	if (ret < 0)
+		return ret;
+	uV = ret;
+
+	chan = priv->port[id].chan[0];
+	ret = tps23881_pi_get_chan_current(priv, chan);
+	if (ret < 0)
+		return ret;
+	uA = ret;
+
+	if (priv->port[id].is_4p) {
+		chan = priv->port[id].chan[1];
+		ret = tps23881_pi_get_chan_current(priv, chan);
+		if (ret < 0)
+			return ret;
+		uA += ret;
+	}
+
+	tmp_64 = uV;
+	tmp_64 *= uA;
+	/* mW = uV * uA / 1000000000 */
+	return DIV_ROUND_CLOSEST_ULL(tmp_64, 1000000000);
+}
+
+static int
+tps23881_pi_get_pw_limit_chan(struct tps23881_priv *priv, u8 chan)
+{
+	struct i2c_client *client = priv->client;
+	int ret, reg;
+	u16 val;
+
+	reg = TPS23881_REG_2PAIR_POL1 + (chan % 4);
+	ret = i2c_smbus_read_word_data(client, reg);
+	if (ret < 0)
+		return ret;
+
+	val = tps23881_calc_val(ret, chan, 0, 0xff);
+	return val * TPS23881_MW_STEP;
+}
+
+static int tps23881_pi_get_pw_limit(struct pse_controller_dev *pcdev, int id)
+{
+	struct tps23881_priv *priv = to_tps23881_priv(pcdev);
+	int ret, mW;
+	u8 chan;
+
+	chan = priv->port[id].chan[0];
+	ret = tps23881_pi_get_pw_limit_chan(priv, chan);
+	if (ret < 0)
+		return ret;
+
+	mW = ret;
+	if (priv->port[id].is_4p) {
+		chan = priv->port[id].chan[1];
+		ret = tps23881_pi_get_pw_limit_chan(priv, chan);
+		if (ret < 0)
+			return ret;
+		mW += ret;
+	}
+
+	return mW;
+}
+
+static int tps23881_pi_set_pw_limit(struct pse_controller_dev *pcdev,
+				    int id, int max_mW)
+{
+	struct tps23881_priv *priv = to_tps23881_priv(pcdev);
+	u8 pw_pol;
+	int ret;
+
+	if (max_mW < TPS23881_MIN_PI_PW_LIMIT_MW || MAX_PI_PW < max_mW) {
+		dev_err(&priv->client->dev,
+			"power limit %d out of ranges [%d,%d]",
+			max_mW, TPS23881_MIN_PI_PW_LIMIT_MW, MAX_PI_PW);
+		return -ERANGE;
+	}
+
+	ret = tps23881_pi_enable_manual_pol(priv, id);
+	if (ret < 0)
+		return ret;
+
+	pw_pol = DIV_ROUND_CLOSEST_ULL(max_mW, TPS23881_MW_STEP);
+
+	/* Save power policy to reconfigure it after a disabled call */
+	priv->port[id].pw_pol = pw_pol;
+	return tps23881_pi_set_pw_pol_limit(priv, id, pw_pol,
+					    priv->port[id].is_4p);
+}
+
+static int
+tps23881_pi_get_pw_limit_ranges(struct pse_controller_dev *pcdev, int id,
+				struct pse_pw_limit_ranges *pw_limit_ranges)
+{
+	struct ethtool_c33_pse_pw_limit_range *c33_pw_limit_ranges;
+
+	c33_pw_limit_ranges = kzalloc(sizeof(*c33_pw_limit_ranges),
+				      GFP_KERNEL);
+	if (!c33_pw_limit_ranges)
+		return -ENOMEM;
+
+	c33_pw_limit_ranges->min = TPS23881_MIN_PI_PW_LIMIT_MW;
+	c33_pw_limit_ranges->max = MAX_PI_PW;
+	pw_limit_ranges->c33_pw_limit_ranges = c33_pw_limit_ranges;
+
+	/* Return the number of ranges */
+	return 1;
+}
+
 /* Parse managers subnode into a array of device node */
 static int
 tps23881_get_of_channels(struct tps23881_priv *priv,
@@ -540,6 +785,9 @@ tps23881_write_port_matrix(struct tps23881_priv *priv,
 		if (port_matrix[i].exist)
 			priv->port[pi_id].chan[0] = lgcl_chan;
 
+		/* Initialize power policy internal value */
+		priv->port[pi_id].pw_pol = -1;
+
 		/* Set hardware port matrix for all ports */
 		val |= hw_chan << (lgcl_chan * 2);
 
@@ -665,6 +913,12 @@ static const struct pse_controller_ops tps23881_ops = {
 	.pi_disable = tps23881_pi_disable,
 	.pi_get_admin_state = tps23881_pi_get_admin_state,
 	.pi_get_pw_status = tps23881_pi_get_pw_status,
+	.pi_get_pw_class = tps23881_pi_get_pw_class,
+	.pi_get_actual_pw = tps23881_pi_get_actual_pw,
+	.pi_get_voltage = tps23881_pi_get_voltage,
+	.pi_get_pw_limit = tps23881_pi_get_pw_limit,
+	.pi_set_pw_limit = tps23881_pi_set_pw_limit,
+	.pi_get_pw_limit_ranges = tps23881_pi_get_pw_limit_ranges,
 };
 
 static const char fw_parity_name[] = "ti/tps23881/tps23881-parity-14.bin";

-- 
2.34.1