[PATCH net-next 2/2] net: phy: aquantia: add hwmon support

[Heiner Kallweit <hkallweit1@gmail.com>]

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)

Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/net/phy/Makefile         |   2 +-
 drivers/net/phy/aquantia_hwmon.c | 263 +++++++++++++++++++++++++++++++
 drivers/net/phy/aquantia_hwmon.h |  15 ++
 drivers/net/phy/aquantia_main.c  |   4 +
 4 files changed, 283 insertions(+), 1 deletion(-)
 create mode 100644 drivers/net/phy/aquantia_hwmon.c
 create mode 100644 drivers/net/phy/aquantia_hwmon.h

diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index b0845adaf..c48596626 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -45,7 +45,7 @@ sfp-obj-$(CONFIG_SFP)		+= sfp-bus.o
 obj-y				+= $(sfp-obj-y) $(sfp-obj-m)
 
 obj-$(CONFIG_AMD_PHY)		+= amd.o
-aquantia-objs			+= aquantia_main.o
+aquantia-objs			+= aquantia_main.o aquantia_hwmon.o
 obj-$(CONFIG_AQUANTIA_PHY)	+= aquantia.o
 obj-$(CONFIG_ASIX_PHY)		+= asix.o
 obj-$(CONFIG_AT803X_PHY)	+= at803x.o
diff --git a/drivers/net/phy/aquantia_hwmon.c b/drivers/net/phy/aquantia_hwmon.c
new file mode 100644
index 000000000..c0dd695f6
--- /dev/null
+++ b/drivers/net/phy/aquantia_hwmon.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0
+/* HWMON driver for Aquantia PHY
+ *
+ * Author: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
+ * Author: Andrew Lunn <andrew@lunn.ch>
+ * Author: Heiner Kallweit <hkallweit1@gmail.com>
+ */
+
+#include <linux/phy.h>
+#include <linux/device.h>
+#include <linux/ctype.h>
+#include <linux/hwmon.h>
+
+#include "aquantia_hwmon.h"
+
+/* Vendor specific 1, MDIO_MMD_VEND1 */
+#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)
+
+struct aqr_priv {
+	struct device *hwmon_dev;
+	char *hwmon_name;
+};
+
+#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;
+
+	/* register value is 2's complement with LSB = 1/256th degree Celsius */
+	if (temp > 0x8000)
+		temp -= 0x10000;
+
+	*value = 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;
+
+	if (temp < 0)
+		temp += 0x10000;
+
+	return phy_write_mmd(phydev, MDIO_MMD_VEND1, reg, temp);
+}
+
+static int aqr_hwmon_status1(struct phy_device *phydev, int bit, long *value)
+{
+	int reg = phy_read_mmd(phydev, MDIO_MMD_VEND1, VEND1_GENERAL_STAT1);
+
+	if (reg < 0)
+		return reg;
+
+	*value = !!(reg & bit);
+
+	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 = phy_read_mmd(phydev, MDIO_MMD_VEND1,
+				   VEND1_THERMAL_STAT2);
+		if (reg < 0)
+			return reg;
+		if (!(reg & VEND1_THERMAL_STAT2_VALID))
+			return -EIO;
+
+		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,
+};
+
+static int aqr_hwmon_really_probe(struct phy_device *phydev)
+{
+	struct device *dev = &phydev->mdio.dev;
+	struct aqr_priv *priv = phydev->priv;
+	int i, j;
+
+	priv->hwmon_name = devm_kstrdup(dev, dev_name(dev), GFP_KERNEL);
+	if (!priv->hwmon_name)
+		return -ENOMEM;
+
+	for (i = j = 0; priv->hwmon_name[i]; i++) {
+		if (isalnum(priv->hwmon_name[i])) {
+			if (i != j)
+				priv->hwmon_name[j] = priv->hwmon_name[i];
+			j++;
+		}
+	}
+	priv->hwmon_name[j] = '\0';
+
+	priv->hwmon_dev = devm_hwmon_device_register_with_info(dev,
+				priv->hwmon_name, phydev,
+				&aqr_hwmon_chip_info, NULL);
+
+	return PTR_ERR_OR_ZERO(priv->hwmon_dev);
+}
+
+int aqr_hwmon_probe(struct phy_device *phydev)
+{
+	struct aqr_priv *priv;
+
+	priv = devm_kzalloc(&phydev->mdio.dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	phydev->priv = priv;
+
+	return aqr_hwmon_really_probe(phydev);
+}
+
+#endif
diff --git a/drivers/net/phy/aquantia_hwmon.h b/drivers/net/phy/aquantia_hwmon.h
new file mode 100644
index 000000000..607e68758
--- /dev/null
+++ b/drivers/net/phy/aquantia_hwmon.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0
+ * HWMON driver for Aquantia PHY
+ *
+ * Author: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
+ * Author: Andrew Lunn <andrew@lunn.ch>
+ * Author: Heiner Kallweit <hkallweit1@gmail.com>
+ */
+
+#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
diff --git a/drivers/net/phy/aquantia_main.c b/drivers/net/phy/aquantia_main.c
index 0f0eb5682..af6dc3588 100644
--- a/drivers/net/phy/aquantia_main.c
+++ b/drivers/net/phy/aquantia_main.c
@@ -12,6 +12,8 @@
 #include <linux/delay.h>
 #include <linux/phy.h>
 
+#include "aquantia_hwmon.h"
+
 #define PHY_ID_AQ1202	0x03a1b445
 #define PHY_ID_AQ2104	0x03a1b460
 #define PHY_ID_AQR105	0x03a1b4a2
@@ -231,6 +233,7 @@ static struct phy_driver aqr_driver[] = {
 	.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,
@@ -241,6 +244,7 @@ static struct phy_driver aqr_driver[] = {
 	.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,
-- 
2.20.1