net: phy: aquantia: add hwmon support

This adds HWMON support for the temperature sensor and the related
alarms on the 107/108/109 chips. This patch is based on work from
Nikita and Andrew. I added:
- support for changing alarm thresholds via sysfs
- move HWMON code to a separate source file to improve maintainability
- smaller changes like using IS_REACHABLE instead of ifdef
(avoids problems if PHY driver is built in and HWMON is a module)

v2:
- remove struct aqr_priv
- rename header file to aquantia.h
v3:
- add conditional compiling of aquantia_hwmon.c
- improve converting sensor register values to/from long
- add helper aqr_hwmon_test_bit

Signed-off-by: Nikita Yushchenko <[e-mail]>
Signed-off-by: Andrew Lunn <[e-mail]>
Signed-off-by: Heiner Kallweit <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/phy/Makefile

···
 
 obj-$(CONFIG_AMD_PHY)		+= amd.o
 aquantia-objs			+= aquantia_main.o
+ifdef CONFIG_HWMON
+aquantia-objs			+= aquantia_hwmon.o
+endif
 obj-$(CONFIG_AQUANTIA_PHY)	+= aquantia.o
 obj-$(CONFIG_ASIX_PHY)		+= asix.o
 obj-$(CONFIG_AT803X_PHY)	+= at803x.o

drivers/net/phy/aquantia.h

···
+/* SPDX-License-Identifier: GPL-2.0
+ * HWMON driver for Aquantia PHY
+ *
+ * Author: Nikita Yushchenko <[e-mail]>
+ * Author: Andrew Lunn <[e-mail]>
+ * Author: Heiner Kallweit <[e-mail]>
+ */
+
+#include <linux/device.h>
+#include <linux/phy.h>
+
+#if IS_REACHABLE(CONFIG_HWMON)
+int aqr_hwmon_probe(struct phy_device *phydev);
+#else
+static inline int aqr_hwmon_probe(struct phy_device *phydev) { return 0; }
+#endif

drivers/net/phy/aquantia_hwmon.c

···
+// SPDX-License-Identifier: GPL-2.0
+/* HWMON driver for Aquantia PHY
+ *
+ * Author: Nikita Yushchenko <[e-mail]>
+ * Author: Andrew Lunn <[e-mail]>
+ * Author: Heiner Kallweit <[e-mail]>
+ */
+
+#include <linux/phy.h>
+#include <linux/device.h>
+#include <linux/ctype.h>
+#include <linux/hwmon.h>
+
+#include "aquantia.h"
+
+/* Vendor specific 1, MDIO_MMD_VEND2 */
+#define VEND1_THERMAL_PROV_HIGH_TEMP_FAIL	0xc421
+#define VEND1_THERMAL_PROV_LOW_TEMP_FAIL	0xc422
+#define VEND1_THERMAL_PROV_HIGH_TEMP_WARN	0xc423
+#define VEND1_THERMAL_PROV_LOW_TEMP_WARN	0xc424
+#define VEND1_THERMAL_STAT1			0xc820
+#define VEND1_THERMAL_STAT2			0xc821
+#define VEND1_THERMAL_STAT2_VALID		BIT(0)
+#define VEND1_GENERAL_STAT1			0xc830
+#define VEND1_GENERAL_STAT1_HIGH_TEMP_FAIL	BIT(14)
+#define VEND1_GENERAL_STAT1_LOW_TEMP_FAIL	BIT(13)
+#define VEND1_GENERAL_STAT1_HIGH_TEMP_WARN	BIT(12)
+#define VEND1_GENERAL_STAT1_LOW_TEMP_WARN	BIT(11)
+
+#if IS_REACHABLE(CONFIG_HWMON)
+
+static umode_t aqr_hwmon_is_visible(const void *data,
+				    enum hwmon_sensor_types type,
+				    u32 attr, int channel)
+{
+	if (type != hwmon_temp)
+		return 0;
+
+	switch (attr) {
+	case hwmon_temp_input:
+	case hwmon_temp_min_alarm:
+	case hwmon_temp_max_alarm:
+	case hwmon_temp_lcrit_alarm:
+	case hwmon_temp_crit_alarm:
+		return 0444;
+	case hwmon_temp_min:
+	case hwmon_temp_max:
+	case hwmon_temp_lcrit:
+	case hwmon_temp_crit:
+		return 0644;
+	default:
+		return 0;
+	}
+}
+
+static int aqr_hwmon_get(struct phy_device *phydev, int reg, long *value)
+{
+	int temp = phy_read_mmd(phydev, MDIO_MMD_VEND1, reg);
+
+	if (temp < 0)
+		return temp;
+
+	/* 16 bit value is 2's complement with LSB = 1/256th degree Celsius */
+	*value = (s16)temp * 1000 / 256;
+
+	return 0;
+}
+
+static int aqr_hwmon_set(struct phy_device *phydev, int reg, long value)
+{
+	int temp;
+
+	if (value >= 128000 || value < -128000)
+		return -ERANGE;
+
+	temp = value * 256 / 1000;
+
+	/* temp is in s16 range and we're interested in lower 16 bits only */
+	return phy_write_mmd(phydev, MDIO_MMD_VEND1, reg, (u16)temp);
+}
+
+static int aqr_hwmon_test_bit(struct phy_device *phydev, int reg, int bit)
+{
+	int val = phy_read_mmd(phydev, MDIO_MMD_VEND1, reg);
+
+	if (val < 0)
+		return val;
+
+	return !!(val & bit);
+}
+
+static int aqr_hwmon_status1(struct phy_device *phydev, int bit, long *value)
+{
+	int val = aqr_hwmon_test_bit(phydev, VEND1_GENERAL_STAT1, bit);
+
+	if (val < 0)
+		return val;
+
+	*value = val;
+
+	return 0;
+}
+
+static int aqr_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+			  u32 attr, int channel, long *value)
+{
+	struct phy_device *phydev = dev_get_drvdata(dev);
+	int reg;
+
+	if (type != hwmon_temp)
+		return -EOPNOTSUPP;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		reg = aqr_hwmon_test_bit(phydev, VEND1_THERMAL_STAT2,
+					 VEND1_THERMAL_STAT2_VALID);
+		if (reg < 0)
+			return reg;
+		if (!reg)
+			return -EBUSY;
+
+		return aqr_hwmon_get(phydev, VEND1_THERMAL_STAT1, value);
+
+	case hwmon_temp_lcrit:
+		return aqr_hwmon_get(phydev, VEND1_THERMAL_PROV_LOW_TEMP_FAIL,
+				     value);
+	case hwmon_temp_min:
+		return aqr_hwmon_get(phydev, VEND1_THERMAL_PROV_LOW_TEMP_WARN,
+				     value);
+	case hwmon_temp_max:
+		return aqr_hwmon_get(phydev, VEND1_THERMAL_PROV_HIGH_TEMP_WARN,
+				     value);
+	case hwmon_temp_crit:
+		return aqr_hwmon_get(phydev, VEND1_THERMAL_PROV_HIGH_TEMP_FAIL,
+				     value);
+	case hwmon_temp_lcrit_alarm:
+		return aqr_hwmon_status1(phydev,
+					 VEND1_GENERAL_STAT1_LOW_TEMP_FAIL,
+					 value);
+	case hwmon_temp_min_alarm:
+		return aqr_hwmon_status1(phydev,
+					 VEND1_GENERAL_STAT1_LOW_TEMP_WARN,
+					 value);
+	case hwmon_temp_max_alarm:
+		return aqr_hwmon_status1(phydev,
+					 VEND1_GENERAL_STAT1_HIGH_TEMP_WARN,
+					 value);
+	case hwmon_temp_crit_alarm:
+		return aqr_hwmon_status1(phydev,
+					 VEND1_GENERAL_STAT1_HIGH_TEMP_FAIL,
+					 value);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int aqr_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
+			   u32 attr, int channel, long value)
+{
+	struct phy_device *phydev = dev_get_drvdata(dev);
+
+	if (type != hwmon_temp)
+		return -EOPNOTSUPP;
+
+	switch (attr) {
+	case hwmon_temp_lcrit:
+		return aqr_hwmon_set(phydev, VEND1_THERMAL_PROV_LOW_TEMP_FAIL,
+				     value);
+	case hwmon_temp_min:
+		return aqr_hwmon_set(phydev, VEND1_THERMAL_PROV_LOW_TEMP_WARN,
+				     value);
+	case hwmon_temp_max:
+		return aqr_hwmon_set(phydev, VEND1_THERMAL_PROV_HIGH_TEMP_WARN,
+				     value);
+	case hwmon_temp_crit:
+		return aqr_hwmon_set(phydev, VEND1_THERMAL_PROV_HIGH_TEMP_FAIL,
+				     value);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static const struct hwmon_ops aqr_hwmon_ops = {
+	.is_visible = aqr_hwmon_is_visible,
+	.read = aqr_hwmon_read,
+	.write = aqr_hwmon_write,
+};
+
+static u32 aqr_hwmon_chip_config[] = {
+	HWMON_C_REGISTER_TZ,
+	0,
+};
+
+static const struct hwmon_channel_info aqr_hwmon_chip = {
+	.type = hwmon_chip,
+	.config = aqr_hwmon_chip_config,
+};
+
+static u32 aqr_hwmon_temp_config[] = {
+	HWMON_T_INPUT |
+	HWMON_T_MAX | HWMON_T_MIN |
+	HWMON_T_MAX_ALARM | HWMON_T_MIN_ALARM |
+	HWMON_T_CRIT | HWMON_T_LCRIT |
+	HWMON_T_CRIT_ALARM | HWMON_T_LCRIT_ALARM,
+	0,
+};
+
+static const struct hwmon_channel_info aqr_hwmon_temp = {
+	.type = hwmon_temp,
+	.config = aqr_hwmon_temp_config,
+};
+
+static const struct hwmon_channel_info *aqr_hwmon_info[] = {
+	&aqr_hwmon_chip,
+	&aqr_hwmon_temp,
+	NULL,
+};
+
+static const struct hwmon_chip_info aqr_hwmon_chip_info = {
+	.ops = &aqr_hwmon_ops,
+	.info = aqr_hwmon_info,
+};
+
+int aqr_hwmon_probe(struct phy_device *phydev)
+{
+	struct device *dev = &phydev->mdio.dev;
+	struct device *hwmon_dev;
+	char *hwmon_name;
+	int i, j;
+
+	hwmon_name = devm_kstrdup(dev, dev_name(dev), GFP_KERNEL);
+	if (!hwmon_name)
+		return -ENOMEM;
+
+	for (i = j = 0; hwmon_name[i]; i++) {
+		if (isalnum(hwmon_name[i])) {
+			if (i != j)
+				hwmon_name[j] = hwmon_name[i];
+			j++;
+		}
+	}
+	hwmon_name[j] = '\0';
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, hwmon_name,
+					phydev, &aqr_hwmon_chip_info, NULL);
+
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+#endif

drivers/net/phy/aquantia_main.c

···
 #include <linux/delay.h>
 #include <linux/phy.h>
 
+#include "aquantia.h"
+
 #define PHY_ID_AQ1202	0x03a1b445
 #define PHY_ID_AQ2104	0x03a1b460
 #define PHY_ID_AQR105	0x03a1b4a2
···
 	.name		= "Aquantia AQR107",
 	.aneg_done	= genphy_c45_aneg_done,
 	.get_features	= genphy_c45_pma_read_abilities,
+	.probe		= aqr_hwmon_probe,
 	.config_aneg    = aqr_config_aneg,
 	.config_intr	= aqr_config_intr,
 	.ack_interrupt	= aqr_ack_interrupt,
···
 	.name		= "Aquantia AQCS109",
 	.aneg_done	= genphy_c45_aneg_done,
 	.get_features	= genphy_c45_pma_read_abilities,
+	.probe		= aqr_hwmon_probe,
 	.config_init	= aqcs109_config_init,
 	.config_aneg    = aqr_config_aneg,
 	.config_intr	= aqr_config_intr,