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Date:   Thu, 18 Mar 2021 15:17:14 +0100
From:   Wilken Gottwalt <wilken.gottwalt@posteo.net>
To:     linux-kernel@vger.kernel.org
Cc:     Jean Delvare <jdelvare@suse.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Jonathan Corbet <corbet@lwn.net>, linux-hwmon@vger.kernel.org
Subject: [PATCH v4] hwmon: corsair-psu: add support for critical values
Message-ID: <YFNg6vGk3sQmyqgB@monster.powergraphx.local>
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Precedence: bulk

Adds support for reading the critical values of the temperature sensors
and the rail sensors (voltage and current) once and caches them. Updates
the naming of the constants following a more clear scheme. Also updates
the documentation and fixes some typos. Updates is_visible and ops_read
functions to be more readable.

The new sensors output of a Corsair HX850i will look like this:
corsairpsu-hid-3-1
Adapter: HID adapter
v_in:        230.00 V
v_out +12v:   12.14 V  (crit min =  +8.41 V, crit max = +15.59 V)
v_out +5v:     5.03 V  (crit min =  +3.50 V, crit max =  +6.50 V)
v_out +3.3v:   3.30 V  (crit min =  +2.31 V, crit max =  +4.30 V)
psu fan:        0 RPM
vrm temp:     +46.2?C  (crit = +70.0?C)
case temp:    +39.8?C  (crit = +70.0?C)
power total: 152.00 W
power +12v:  108.00 W
power +5v:    41.00 W
power +3.3v:   5.00 W
curr +12v:     9.00 A  (crit max = +85.00 A)
curr +5v:      8.31 A  (crit max = +40.00 A)
curr +3.3v:    1.62 A  (crit max = +40.00 A)

Signed-off-by: Wilken Gottwalt <wilken.gottwalt@posteo.net>
---
Changed in v4:
  - simplified private data structure and collection of critical values and
    unsupported command check

Changes in v3:
  - introduced a quirk check function to catch non-working commands
  - split is_visible function into subfunctions
  - moved the "is value valid" checks into the is_visibility subfunction
  - simplified hwmon_ops_read function
  - rearranged sysfs entries in the documentation like suggested

Changes in v2:
  - simplified reading/caching of critical values and hwmon_ops_read function
  - removed unnecessary debug output and comments
---
 Documentation/hwmon/corsair-psu.rst |  13 +-
 drivers/hwmon/corsair-psu.c         | 325 +++++++++++++++++++++++-----
 2 files changed, 282 insertions(+), 56 deletions(-)

diff --git a/Documentation/hwmon/corsair-psu.rst b/Documentation/hwmon/corsair-psu.rst
index 396b95c9a76a..e8378e7a1d8c 100644
--- a/Documentation/hwmon/corsair-psu.rst
+++ b/Documentation/hwmon/corsair-psu.rst
@@ -47,19 +47,30 @@ Sysfs entries
 =======================	========================================================
 curr1_input		Total current usage
 curr2_input		Current on the 12v psu rail
+curr2_crit		Current max critical value on the 12v psu rail
 curr3_input		Current on the 5v psu rail
+curr3_crit		Current max critical value on the 5v psu rail
 curr4_input		Current on the 3.3v psu rail
+curr4_crit		Current max critical value on the 3.3v psu rail
 fan1_input		RPM of psu fan
 in0_input		Voltage of the psu ac input
 in1_input		Voltage of the 12v psu rail
+in1_crit		Voltage max critical value on the 12v psu rail
+in1_lcrit		Voltage min critical value on the 12v psu rail
 in2_input		Voltage of the 5v psu rail
-in3_input		Voltage of the 3.3 psu rail
+in2_crit		Voltage max critical value on the 5v psu rail
+in2_lcrit		Voltage min critical value on the 5v psu rail
+in3_input		Voltage of the 3.3v psu rail
+in3_crit		Voltage max critical value on the 3.3v psu rail
+in3_lcrit		Voltage min critical value on the 3.3v psu rail
 power1_input		Total power usage
 power2_input		Power usage of the 12v psu rail
 power3_input		Power usage of the 5v psu rail
 power4_input		Power usage of the 3.3v psu rail
 temp1_input		Temperature of the psu vrm component
+temp1_crit		Temperature max cirtical value of the psu vrm component
 temp2_input		Temperature of the psu case
+temp2_crit		Temperature max critical value of psu case
 =======================	========================================================
 
 Usage Notes
diff --git a/drivers/hwmon/corsair-psu.c b/drivers/hwmon/corsair-psu.c
index b0953eeeb2d3..3a5807e4a2ef 100644
--- a/drivers/hwmon/corsair-psu.c
+++ b/drivers/hwmon/corsair-psu.c
@@ -53,11 +53,17 @@
 #define CMD_TIMEOUT_MS		250
 #define SECONDS_PER_HOUR	(60 * 60)
 #define SECONDS_PER_DAY		(SECONDS_PER_HOUR * 24)
+#define RAIL_COUNT		3 /* 3v3 + 5v + 12v */
+#define TEMP_COUNT		2
 
 #define PSU_CMD_SELECT_RAIL	0x00 /* expects length 2 */
-#define PSU_CMD_IN_VOLTS	0x88 /* the rest of the commands expect length 3 */
+#define PSU_CMD_RAIL_VOLTS_HCRIT 0x40 /* the rest of the commands expect length 3 */
+#define PSU_CMD_RAIL_VOLTS_LCRIT 0x44
+#define PSU_CMD_RAIL_AMPS_HCRIT	0x46
+#define PSU_CMD_TEMP_HCRIT	0x4F
+#define PSU_CMD_IN_VOLTS	0x88
 #define PSU_CMD_IN_AMPS		0x89
-#define PSU_CMD_RAIL_OUT_VOLTS	0x8B
+#define PSU_CMD_RAIL_VOLTS	0x8B
 #define PSU_CMD_RAIL_AMPS	0x8C
 #define PSU_CMD_TEMP0		0x8D
 #define PSU_CMD_TEMP1		0x8E
@@ -116,6 +122,15 @@ struct corsairpsu_data {
 	u8 *cmd_buffer;
 	char vendor[REPLY_SIZE];
 	char product[REPLY_SIZE];
+	long temp_crit[TEMP_COUNT];
+	long in_crit[RAIL_COUNT];
+	long in_lcrit[RAIL_COUNT];
+	long curr_crit[RAIL_COUNT];
+	u8 temp_crit_support;
+	u8 in_crit_support;
+	u8 in_lcrit_support;
+	u8 curr_crit_support;
+	bool in_curr_cmd_support; /* not all commands are supported on every PSU */
 };
 
 /* some values are SMBus LINEAR11 data which need a conversion */
@@ -193,7 +208,10 @@ static int corsairpsu_request(struct corsairpsu_data *priv, u8 cmd, u8 rail, voi
 
 	mutex_lock(&priv->lock);
 	switch (cmd) {
-	case PSU_CMD_RAIL_OUT_VOLTS:
+	case PSU_CMD_RAIL_VOLTS_HCRIT:
+	case PSU_CMD_RAIL_VOLTS_LCRIT:
+	case PSU_CMD_RAIL_AMPS_HCRIT:
+	case PSU_CMD_RAIL_VOLTS:
 	case PSU_CMD_RAIL_AMPS:
 	case PSU_CMD_RAIL_WATTS:
 		ret = corsairpsu_usb_cmd(priv, 2, PSU_CMD_SELECT_RAIL, rail, NULL);
@@ -229,9 +247,13 @@ static int corsairpsu_get_value(struct corsairpsu_data *priv, u8 cmd, u8 rail, l
 	 */
 	tmp = ((long)data[3] << 24) + (data[2] << 16) + (data[1] << 8) + data[0];
 	switch (cmd) {
+	case PSU_CMD_RAIL_VOLTS_HCRIT:
+	case PSU_CMD_RAIL_VOLTS_LCRIT:
+	case PSU_CMD_RAIL_AMPS_HCRIT:
+	case PSU_CMD_TEMP_HCRIT:
 	case PSU_CMD_IN_VOLTS:
 	case PSU_CMD_IN_AMPS:
-	case PSU_CMD_RAIL_OUT_VOLTS:
+	case PSU_CMD_RAIL_VOLTS:
 	case PSU_CMD_RAIL_AMPS:
 	case PSU_CMD_TEMP0:
 	case PSU_CMD_TEMP1:
@@ -256,75 +278,265 @@ static int corsairpsu_get_value(struct corsairpsu_data *priv, u8 cmd, u8 rail, l
 	return ret;
 }
 
-static umode_t corsairpsu_hwmon_ops_is_visible(const void *data, enum hwmon_sensor_types type,
-					       u32 attr, int channel)
+static void corsairpsu_get_criticals(struct corsairpsu_data *priv)
 {
-	if (type == hwmon_temp && (attr == hwmon_temp_input || attr == hwmon_temp_label))
-		return 0444;
-	else if (type == hwmon_fan && (attr == hwmon_fan_input || attr == hwmon_fan_label))
-		return 0444;
-	else if (type == hwmon_power && (attr == hwmon_power_input || attr == hwmon_power_label))
-		return 0444;
-	else if (type == hwmon_in && (attr == hwmon_in_input || attr == hwmon_in_label))
+	long tmp;
+	int rail;
+
+	for (rail = 0; rail < TEMP_COUNT; ++rail) {
+		if (!corsairpsu_get_value(priv, PSU_CMD_TEMP_HCRIT, rail, &tmp)) {
+			priv->temp_crit_support |= BIT(rail);
+			priv->temp_crit[rail] = tmp;
+		}
+	}
+
+	for (rail = 0; rail < RAIL_COUNT; ++rail) {
+		if (!corsairpsu_get_value(priv, PSU_CMD_RAIL_VOLTS_HCRIT, rail, &tmp)) {
+			priv->in_crit_support |= BIT(rail);
+			priv->in_crit[rail] = tmp;
+		}
+
+		if (!corsairpsu_get_value(priv, PSU_CMD_RAIL_VOLTS_LCRIT, rail, &tmp)) {
+			priv->in_lcrit_support |= BIT(rail);
+			priv->in_lcrit[rail] = tmp;
+		}
+
+		if (!corsairpsu_get_value(priv, PSU_CMD_RAIL_AMPS_HCRIT, rail, &tmp)) {
+			priv->curr_crit_support |= BIT(rail);
+			priv->curr_crit[rail] = tmp;
+		}
+	}
+}
+
+static void corsairpsu_check_cmd_support(struct corsairpsu_data *priv)
+{
+	long tmp;
+
+	priv->in_curr_cmd_support = !corsairpsu_get_value(priv, PSU_CMD_IN_AMPS, 0, &tmp);
+}
+
+static umode_t corsairpsu_hwmon_temp_is_visible(const struct corsairpsu_data *priv, u32 attr,
+						int channel)
+{
+	umode_t res = 0444;
+
+	switch (attr) {
+	case hwmon_temp_input:
+	case hwmon_temp_label:
+	case hwmon_temp_crit:
+		if (channel > 0 && !(priv->temp_crit_support & BIT(channel - 1)))
+			res = 0;
+		break;
+	default:
+		break;
+	}
+
+	return res;
+}
+
+static umode_t corsairpsu_hwmon_fan_is_visible(const struct corsairpsu_data *priv, u32 attr,
+					       int channel)
+{
+	switch (attr) {
+	case hwmon_fan_input:
+	case hwmon_fan_label:
 		return 0444;
-	else if (type == hwmon_curr && (attr == hwmon_curr_input || attr == hwmon_curr_label))
+	default:
+		return 0;
+	}
+}
+
+static umode_t corsairpsu_hwmon_power_is_visible(const struct corsairpsu_data *priv, u32 attr,
+						 int channel)
+{
+	switch (attr) {
+	case hwmon_power_input:
+	case hwmon_power_label:
 		return 0444;
+	default:
+		return 0;
+	};
+}
 
-	return 0;
+static umode_t corsairpsu_hwmon_in_is_visible(const struct corsairpsu_data *priv, u32 attr,
+					      int channel)
+{
+	umode_t res = 0444;
+
+	switch (attr) {
+	case hwmon_in_input:
+	case hwmon_in_label:
+	case hwmon_in_crit:
+		if (channel > 0 && !(priv->in_crit_support & BIT(channel - 1)))
+			res = 0;
+		break;
+	case hwmon_in_lcrit:
+		if (channel > 0 && !(priv->in_lcrit_support & BIT(channel - 1)))
+			res = 0;
+		break;
+	default:
+		break;
+	};
+
+	return res;
 }
 
-static int corsairpsu_hwmon_ops_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
-				     int channel, long *val)
+static umode_t corsairpsu_hwmon_curr_is_visible(const struct corsairpsu_data *priv, u32 attr,
+						int channel)
 {
-	struct corsairpsu_data *priv = dev_get_drvdata(dev);
-	int ret;
+	umode_t res = 0444;
 
-	if (type == hwmon_temp && attr == hwmon_temp_input && channel < 2) {
-		ret = corsairpsu_get_value(priv, channel ? PSU_CMD_TEMP1 : PSU_CMD_TEMP0, channel,
-					   val);
-	} else if (type == hwmon_fan && attr == hwmon_fan_input) {
-		ret = corsairpsu_get_value(priv, PSU_CMD_FAN, 0, val);
-	} else if (type == hwmon_power && attr == hwmon_power_input) {
+	switch (attr) {
+	case hwmon_curr_input:
+		if (channel == 0 && !priv->in_curr_cmd_support)
+			res = 0;
+		break;
+	case hwmon_curr_label:
+	case hwmon_curr_crit:
+		if (channel > 0 && !(priv->curr_crit_support & BIT(channel - 1)))
+			res = 0;
+		break;
+	default:
+		break;
+	}
+
+	return res;
+}
+
+static umode_t corsairpsu_hwmon_ops_is_visible(const void *data, enum hwmon_sensor_types type,
+					       u32 attr, int channel)
+{
+	const struct corsairpsu_data *priv = data;
+
+	switch (type) {
+	case hwmon_temp:
+		return corsairpsu_hwmon_temp_is_visible(priv, attr, channel);
+	case hwmon_fan:
+		return corsairpsu_hwmon_fan_is_visible(priv, attr, channel);
+	case hwmon_power:
+		return corsairpsu_hwmon_power_is_visible(priv, attr, channel);
+	case hwmon_in:
+		return corsairpsu_hwmon_in_is_visible(priv, attr, channel);
+	case hwmon_curr:
+		return corsairpsu_hwmon_curr_is_visible(priv, attr, channel);
+	default:
+		return 0;
+	}
+}
+
+static int corsairpsu_hwmon_temp_read(struct corsairpsu_data *priv, u32 attr, int channel,
+				      long *val)
+{
+	int err = -EOPNOTSUPP;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		return corsairpsu_get_value(priv, channel ? PSU_CMD_TEMP1 : PSU_CMD_TEMP0,
+					    channel, val);
+	case hwmon_temp_crit:
+		*val = priv->temp_crit[channel];
+		err = 0;
+		break;
+	default:
+		break;
+	}
+
+	return err;
+}
+
+static int corsairpsu_hwmon_power_read(struct corsairpsu_data *priv, u32 attr, int channel,
+				       long *val)
+{
+	if (attr == hwmon_power_input) {
 		switch (channel) {
 		case 0:
-			ret = corsairpsu_get_value(priv, PSU_CMD_TOTAL_WATTS, 0, val);
-			break;
+			return corsairpsu_get_value(priv, PSU_CMD_TOTAL_WATTS, 0, val);
 		case 1 ... 3:
-			ret = corsairpsu_get_value(priv, PSU_CMD_RAIL_WATTS, channel - 1, val);
-			break;
+			return corsairpsu_get_value(priv, PSU_CMD_RAIL_WATTS, channel - 1, val);
 		default:
-			return -EOPNOTSUPP;
+			break;
 		}
-	} else if (type == hwmon_in && attr == hwmon_in_input) {
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static int corsairpsu_hwmon_in_read(struct corsairpsu_data *priv, u32 attr, int channel, long *val)
+{
+	int err = -EOPNOTSUPP;
+
+	switch (attr) {
+	case hwmon_in_input:
 		switch (channel) {
 		case 0:
-			ret = corsairpsu_get_value(priv, PSU_CMD_IN_VOLTS, 0, val);
-			break;
+			return corsairpsu_get_value(priv, PSU_CMD_IN_VOLTS, 0, val);
 		case 1 ... 3:
-			ret = corsairpsu_get_value(priv, PSU_CMD_RAIL_OUT_VOLTS, channel - 1, val);
-			break;
+			return corsairpsu_get_value(priv, PSU_CMD_RAIL_VOLTS, channel - 1, val);
 		default:
-			return -EOPNOTSUPP;
+			break;
 		}
-	} else if (type == hwmon_curr && attr == hwmon_curr_input) {
+		break;
+	case hwmon_in_crit:
+		*val = priv->in_crit[channel - 1];
+		err = 0;
+		break;
+	case hwmon_in_lcrit:
+		*val = priv->in_lcrit[channel - 1];
+		err = 0;
+		break;
+	}
+
+	return err;
+}
+
+static int corsairpsu_hwmon_curr_read(struct corsairpsu_data *priv, u32 attr, int channel,
+				      long *val)
+{
+	int err = -EOPNOTSUPP;
+
+	switch (attr) {
+	case hwmon_curr_input:
 		switch (channel) {
 		case 0:
-			ret = corsairpsu_get_value(priv, PSU_CMD_IN_AMPS, 0, val);
-			break;
+			return corsairpsu_get_value(priv, PSU_CMD_IN_AMPS, 0, val);
 		case 1 ... 3:
-			ret = corsairpsu_get_value(priv, PSU_CMD_RAIL_AMPS, channel - 1, val);
-			break;
+			return corsairpsu_get_value(priv, PSU_CMD_RAIL_AMPS, channel - 1, val);
 		default:
-			return -EOPNOTSUPP;
+			break;
 		}
-	} else {
-		return -EOPNOTSUPP;
+		break;
+	case hwmon_curr_crit:
+		*val = priv->curr_crit[channel - 1];
+		err = 0;
+		break;
+	default:
+		break;
 	}
 
-	if (ret < 0)
-		return ret;
+	return err;
+}
 
-	return 0;
+static int corsairpsu_hwmon_ops_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+				     int channel, long *val)
+{
+	struct corsairpsu_data *priv = dev_get_drvdata(dev);
+
+	switch (type) {
+	case hwmon_temp:
+		return corsairpsu_hwmon_temp_read(priv, attr, channel, val);
+	case hwmon_fan:
+		if (attr == hwmon_fan_input)
+			return corsairpsu_get_value(priv, PSU_CMD_FAN, 0, val);
+		return -EOPNOTSUPP;
+	case hwmon_power:
+		return corsairpsu_hwmon_power_read(priv, attr, channel, val);
+	case hwmon_in:
+		return corsairpsu_hwmon_in_read(priv, attr, channel, val);
+	case hwmon_curr:
+		return corsairpsu_hwmon_curr_read(priv, attr, channel, val);
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
 static int corsairpsu_hwmon_ops_read_string(struct device *dev, enum hwmon_sensor_types type,
@@ -360,8 +572,8 @@ static const struct hwmon_channel_info *corsairpsu_info[] = {
 	HWMON_CHANNEL_INFO(chip,
 			   HWMON_C_REGISTER_TZ),
 	HWMON_CHANNEL_INFO(temp,
-			   HWMON_T_INPUT | HWMON_T_LABEL,
-			   HWMON_T_INPUT | HWMON_T_LABEL),
+			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT,
+			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT),
 	HWMON_CHANNEL_INFO(fan,
 			   HWMON_F_INPUT | HWMON_F_LABEL),
 	HWMON_CHANNEL_INFO(power,
@@ -371,14 +583,14 @@ static const struct hwmon_channel_info *corsairpsu_info[] = {
 			   HWMON_P_INPUT | HWMON_P_LABEL),
 	HWMON_CHANNEL_INFO(in,
 			   HWMON_I_INPUT | HWMON_I_LABEL,
-			   HWMON_I_INPUT | HWMON_I_LABEL,
-			   HWMON_I_INPUT | HWMON_I_LABEL,
-			   HWMON_I_INPUT | HWMON_I_LABEL),
+			   HWMON_I_INPUT | HWMON_I_LABEL | HWMON_I_LCRIT | HWMON_I_CRIT,
+			   HWMON_I_INPUT | HWMON_I_LABEL | HWMON_I_LCRIT | HWMON_I_CRIT,
+			   HWMON_I_INPUT | HWMON_I_LABEL | HWMON_I_LCRIT | HWMON_I_CRIT),
 	HWMON_CHANNEL_INFO(curr,
 			   HWMON_C_INPUT | HWMON_C_LABEL,
-			   HWMON_C_INPUT | HWMON_C_LABEL,
-			   HWMON_C_INPUT | HWMON_C_LABEL,
-			   HWMON_C_INPUT | HWMON_C_LABEL),
+			   HWMON_C_INPUT | HWMON_C_LABEL | HWMON_C_CRIT,
+			   HWMON_C_INPUT | HWMON_C_LABEL | HWMON_C_CRIT,
+			   HWMON_C_INPUT | HWMON_C_LABEL | HWMON_C_CRIT),
 	NULL
 };
 
@@ -513,6 +725,9 @@ static int corsairpsu_probe(struct hid_device *hdev, const struct hid_device_id
 		goto fail_and_stop;
 	}
 
+	corsairpsu_get_criticals(priv);
+	corsairpsu_check_cmd_support(priv);
+
 	priv->hwmon_dev = hwmon_device_register_with_info(&hdev->dev, "corsairpsu", priv,
 							  &corsairpsu_chip_info, 0);
 
-- 
2.30.2