Message-ID: <20200419143707.GA226840@roeck-us.net>
Date:   Sun, 19 Apr 2020 07:37:07 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Michael Walle <michael@...le.cc>
Cc:     linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, Jean Delvare <jdelvare@...e.com>,
        Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        "David S . Miller" <davem@...emloft.net>
Subject: Re: [PATCH net-next v2 3/3] net: phy: bcm54140: add hwmon support

On Sun, Apr 19, 2020 at 12:12:49PM +0200, Michael Walle wrote:
> The PHY supports monitoring its die temperature as well as two analog
> voltages. Add support for it.
> 
> Signed-off-by: Michael Walle <michael@...le.cc>
> ---
> changes since v1:
>  - add IS_ENABLED(CONFIG_HWMON) guards
>  - clamp values before conversion
>  - add mutex alarm_lock
>  - use mdiobus_get_phy()
>  - make CONFIG_BCM54140_PHY depend on HWMON (or disabled altogether)
>  - add BCM54140_HWMON_IN_xx(ch) macros
> 
> Btw. is it possible to rely on the compiler to strip away unused
> function calls. For exmaple, instead of using the
> #if IS_ENABLED(CONFIG_HWMON) guards, one could use the following:
> 
>   if (IS_ENABLED(CONFIG_HWMON))
>     if (!bcm54140_is_pkg_init(phydev)) {
>       ret = bcm54140_phy_probe_once(phydev);
>       if (ret)
>         return ret;
>     }
>   }
> 
> This will then optimize away the devm_hwmon_device_register() call.
> 

Personally I'd probably implement the hwmon functionality in a separate
file instead, but that it really your and the maintainer's call.

Nitpick below, in case you resend. Either case, feel free to add

Acked-by: Guenter Roeck <linux@...ck-us.net>

Guenter

>  Documentation/hwmon/bcm54140.rst |  45 ++++
>  Documentation/hwmon/index.rst    |   1 +
>  drivers/net/phy/Kconfig          |   1 +
>  drivers/net/phy/bcm54140.c       | 397 +++++++++++++++++++++++++++++++
>  4 files changed, 444 insertions(+)
>  create mode 100644 Documentation/hwmon/bcm54140.rst
> 
> diff --git a/Documentation/hwmon/bcm54140.rst b/Documentation/hwmon/bcm54140.rst
> new file mode 100644
> index 000000000000..bc6ea4b45966
> --- /dev/null
> +++ b/Documentation/hwmon/bcm54140.rst
> @@ -0,0 +1,45 @@
> +.. SPDX-License-Identifier: GPL-2.0-only
> +
> +Broadcom BCM54140 Quad SGMII/QSGMII PHY
> +=======================================
> +
> +Supported chips:
> +
> +   * Broadcom BCM54140
> +
> +     Datasheet: not public
> +
> +Author: Michael Walle <michael@...le.cc>
> +
> +Description
> +-----------
> +
> +The Broadcom BCM54140 is a Quad SGMII/QSGMII PHY which supports monitoring
> +its die temperature as well as two analog voltages.
> +
> +The AVDDL is a 1.0V analogue voltage, the AVDDH is a 3.3V analogue voltage.
> +Both voltages and the temperature are measured in a round-robin fashion.
> +
> +Sysfs entries
> +-------------
> +
> +The following attributes are supported.
> +
> +======================= ========================================================
> +in0_label		"AVDDL"
> +in0_input		Measured AVDDL voltage.
> +in0_min			Minimum AVDDL voltage.
> +in0_max			Maximum AVDDL voltage.
> +in0_alarm		AVDDL voltage alarm.
> +
> +in1_label		"AVDDH"
> +in1_input		Measured AVDDH voltage.
> +in1_min			Minimum AVDDH voltage.
> +in1_max			Maximum AVDDH voltage.
> +in1_alarm		AVDDH voltage alarm.
> +
> +temp1_input		Die temperature.
> +temp1_min		Minimum die temperature.
> +temp1_max		Maximum die temperature.
> +temp1_alarm		Die temperature alarm.
> +======================= ========================================================
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index f022583f96f6..19ad0846736d 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -42,6 +42,7 @@ Hardware Monitoring Kernel Drivers
>     asb100
>     asc7621
>     aspeed-pwm-tacho
> +   bcm54140
>     bel-pfe
>     coretemp
>     da9052
> diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
> index cb7936b577de..bacfee41b564 100644
> --- a/drivers/net/phy/Kconfig
> +++ b/drivers/net/phy/Kconfig
> @@ -349,6 +349,7 @@ config BROADCOM_PHY
>  config BCM54140_PHY
>  	tristate "Broadcom BCM54140 PHY"
>  	depends on PHYLIB
> +	depends on HWMON || HWMON=n
>  	select BCM_NET_PHYLIB
>  	help
>  	  Support the Broadcom BCM54140 Quad SGMII/QSGMII PHY.
> diff --git a/drivers/net/phy/bcm54140.c b/drivers/net/phy/bcm54140.c
> index 97465491b41b..cb0eb58eec76 100644
> --- a/drivers/net/phy/bcm54140.c
> +++ b/drivers/net/phy/bcm54140.c
> @@ -6,6 +6,7 @@
>  
>  #include <linux/bitfield.h>
>  #include <linux/brcmphy.h>
> +#include <linux/hwmon.h>
>  #include <linux/module.h>
>  #include <linux/phy.h>
>  
> @@ -50,6 +51,69 @@
>  #define  BCM54140_RDB_TOP_IMR_PORT1	BIT(5)
>  #define  BCM54140_RDB_TOP_IMR_PORT2	BIT(6)
>  #define  BCM54140_RDB_TOP_IMR_PORT3	BIT(7)
> +#define BCM54140_RDB_MON_CTRL		0x831	/* monitor control */
> +#define  BCM54140_RDB_MON_CTRL_V_MODE	BIT(3)	/* voltage mode */
> +#define  BCM54140_RDB_MON_CTRL_SEL_MASK	GENMASK(2, 1)
> +#define  BCM54140_RDB_MON_CTRL_SEL_TEMP	0	/* meassure temperature */
> +#define  BCM54140_RDB_MON_CTRL_SEL_1V0	1	/* meassure AVDDL 1.0V */
> +#define  BCM54140_RDB_MON_CTRL_SEL_3V3	2	/* meassure AVDDH 3.3V */
> +#define  BCM54140_RDB_MON_CTRL_SEL_RR	3	/* meassure all round-robin */
> +#define  BCM54140_RDB_MON_CTRL_PWR_DOWN	BIT(0)	/* power-down monitor */
> +#define BCM54140_RDB_MON_TEMP_VAL	0x832	/* temperature value */
> +#define BCM54140_RDB_MON_TEMP_MAX	0x833	/* temperature high thresh */
> +#define BCM54140_RDB_MON_TEMP_MIN	0x834	/* temperature low thresh */
> +#define  BCM54140_RDB_MON_TEMP_DATA_MASK GENMASK(9, 0)
> +#define BCM54140_RDB_MON_1V0_VAL	0x835	/* AVDDL 1.0V value */
> +#define BCM54140_RDB_MON_1V0_MAX	0x836	/* AVDDL 1.0V high thresh */
> +#define BCM54140_RDB_MON_1V0_MIN	0x837	/* AVDDL 1.0V low thresh */
> +#define  BCM54140_RDB_MON_1V0_DATA_MASK	GENMASK(10, 0)
> +#define BCM54140_RDB_MON_3V3_VAL	0x838	/* AVDDH 3.3V value */
> +#define BCM54140_RDB_MON_3V3_MAX	0x839	/* AVDDH 3.3V high thresh */
> +#define BCM54140_RDB_MON_3V3_MIN	0x83a	/* AVDDH 3.3V low thresh */
> +#define  BCM54140_RDB_MON_3V3_DATA_MASK	GENMASK(11, 0)
> +#define BCM54140_RDB_MON_ISR		0x83b	/* interrupt status */
> +#define  BCM54140_RDB_MON_ISR_3V3	BIT(2)	/* AVDDH 3.3V alarm */
> +#define  BCM54140_RDB_MON_ISR_1V0	BIT(1)	/* AVDDL 1.0V alarm */
> +#define  BCM54140_RDB_MON_ISR_TEMP	BIT(0)	/* temperature alarm */
> +
> +/* According to the datasheet the formula is:
> + *   T = 413.35 - (0.49055 * bits[9:0])
> + */
> +#define BCM54140_HWMON_TO_TEMP(v) (413350L - (v) * 491)
> +#define BCM54140_HWMON_FROM_TEMP(v) DIV_ROUND_CLOSEST_ULL(413350L - (v), 491)
> +
> +/* According to the datasheet the formula is:
> + *   U = bits[11:0] / 1024 * 220 / 0.2
> + *
> + * Normalized:
> + *   U = bits[11:0] / 4096 * 2514
> + */
> +#define BCM54140_HWMON_TO_IN_1V0(v) ((v) * 2514 >> 11)
> +#define BCM54140_HWMON_FROM_IN_1V0(v) DIV_ROUND_CLOSEST_ULL(((v) << 11), 2514)
> +
> +/* According to the datasheet the formula is:
> + *   U = bits[10:0] / 1024 * 880 / 0.7
> + *
> + * Normalized:
> + *   U = bits[10:0] / 2048 * 4400
> + */
> +#define BCM54140_HWMON_TO_IN_3V3(v) ((v) * 4400 >> 12)
> +#define BCM54140_HWMON_FROM_IN_3V3(v) DIV_ROUND_CLOSEST_ULL(((v) << 12), 4400)
> +
> +#define BCM54140_HWMON_TO_IN(ch, v) ((ch) ? BCM54140_HWMON_TO_IN_3V3(v) \
> +					  : BCM54140_HWMON_TO_IN_1V0(v))
> +#define BCM54140_HWMON_FROM_IN(ch, v) ((ch) ? BCM54140_HWMON_FROM_IN_3V3(v) \
> +					    : BCM54140_HWMON_FROM_IN_1V0(v))
> +#define BCM54140_HWMON_IN_MASK(ch) ((ch) ? BCM54140_RDB_MON_3V3_DATA_MASK \
> +					 : BCM54140_RDB_MON_1V0_DATA_MASK)
> +#define BCM54140_HWMON_IN_VAL_REG(ch) ((ch) ? BCM54140_RDB_MON_3V3_VAL \
> +					    : BCM54140_RDB_MON_1V0_VAL)
> +#define BCM54140_HWMON_IN_MIN_REG(ch) ((ch) ? BCM54140_RDB_MON_3V3_MIN \
> +					    : BCM54140_RDB_MON_1V0_MIN)
> +#define BCM54140_HWMON_IN_MAX_REG(ch) ((ch) ? BCM54140_RDB_MON_3V3_MAX \
> +					    : BCM54140_RDB_MON_1V0_MAX)
> +#define BCM54140_HWMON_IN_ALARM_BIT(ch) ((ch) ? BCM54140_RDB_MON_ISR_3V3 \
> +					      : BCM54140_RDB_MON_ISR_1V0)
>  
>  #define BCM54140_DEFAULT_DOWNSHIFT 5
>  #define BCM54140_MAX_DOWNSHIFT 9
> @@ -57,6 +121,261 @@
>  struct bcm54140_phy_priv {
>  	int port;
>  	int base_addr;
> +#if IS_ENABLED(CONFIG_HWMON)
> +	bool pkg_init;
> +	/* protect the alarm bits */
> +	struct mutex alarm_lock;
> +	u16 alarm;
> +#endif
> +};
> +
> +#if IS_ENABLED(CONFIG_HWMON)
> +static umode_t bcm54140_hwmon_is_visible(const void *data,
> +					 enum hwmon_sensor_types type,
> +					 u32 attr, int channel)
> +{
> +	switch (type) {
> +	case hwmon_in:
> +		switch (attr) {
> +		case hwmon_in_min:
> +		case hwmon_in_max:
> +			return 0644;
> +		case hwmon_in_label:
> +		case hwmon_in_input:
> +		case hwmon_in_alarm:
> +			return 0444;
> +		default:
> +			return 0;
> +		}
> +	case hwmon_temp:
> +		switch (attr) {
> +		case hwmon_temp_min:
> +		case hwmon_temp_max:
> +			return 0644;
> +		case hwmon_temp_input:
> +		case hwmon_temp_alarm:
> +			return 0444;
> +		default:
> +			return 0;
> +		}
> +	default:
> +		return 0;
> +	}
> +}
> +
> +static int bcm54140_hwmon_read_alarm(struct device *dev, unsigned int bit,
> +				     long *val)
> +{
> +	struct phy_device *phydev = dev_get_drvdata(dev);
> +	struct bcm54140_phy_priv *priv = phydev->priv;
> +	int tmp, ret = 0;
> +
> +	mutex_lock(&priv->alarm_lock);
> +
> +	/* latch any alarm bits */
> +	tmp = bcm_phy_read_rdb(phydev, BCM54140_RDB_MON_ISR);
> +	if (tmp < 0) {
> +		ret = tmp;
> +		goto out;
> +	}
> +	priv->alarm |= tmp;
> +
> +	*val = !!(priv->alarm & bit);
> +	priv->alarm &= ~bit;
> +
> +out:
> +	mutex_unlock(&priv->alarm_lock);
> +	return ret;
> +}
> +
> +static int bcm54140_hwmon_read_temp(struct device *dev, u32 attr,
> +				    int channel, long *val)
> +{

This function and the matching write function don't use the 'channel'
argument, so passing it as parameter is not necessary.

> +	struct phy_device *phydev = dev_get_drvdata(dev);
> +	u16 reg, tmp;
> +
> +	switch (attr) {
> +	case hwmon_temp_input:
> +		reg = BCM54140_RDB_MON_TEMP_VAL;
> +		break;
> +	case hwmon_temp_min:
> +		reg = BCM54140_RDB_MON_TEMP_MIN;
> +		break;
> +	case hwmon_temp_max:
> +		reg = BCM54140_RDB_MON_TEMP_MAX;
> +		break;
> +	case hwmon_temp_alarm:
> +		return bcm54140_hwmon_read_alarm(dev,
> +						 BCM54140_RDB_MON_ISR_TEMP,
> +						 val);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	tmp = bcm_phy_read_rdb(phydev, reg);
> +	if (tmp < 0)
> +		return tmp;
> +
> +	*val = BCM54140_HWMON_TO_TEMP(tmp & BCM54140_RDB_MON_TEMP_DATA_MASK);
> +
> +	return 0;
> +}
> +
> +static int bcm54140_hwmon_read_in(struct device *dev, u32 attr,
> +				  int channel, long *val)
> +{
> +	struct phy_device *phydev = dev_get_drvdata(dev);
> +	u16 bit, reg, tmp;
> +
> +	switch (attr) {
> +	case hwmon_in_input:
> +		reg = BCM54140_HWMON_IN_VAL_REG(channel);
> +		break;
> +	case hwmon_in_min:
> +		reg = BCM54140_HWMON_IN_MIN_REG(channel);
> +		break;
> +	case hwmon_in_max:
> +		reg = BCM54140_HWMON_IN_MAX_REG(channel);
> +		break;
> +	case hwmon_in_alarm:
> +		bit = BCM54140_HWMON_IN_ALARM_BIT(channel);
> +		return bcm54140_hwmon_read_alarm(dev, bit, val);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	tmp = bcm_phy_read_rdb(phydev, reg);
> +	if (tmp < 0)
> +		return tmp;
> +
> +	tmp &= BCM54140_HWMON_IN_MASK(channel);
> +	*val = BCM54140_HWMON_TO_IN(channel, tmp);
> +
> +	return 0;
> +}
> +
> +static int bcm54140_hwmon_read(struct device *dev,
> +			       enum hwmon_sensor_types type, u32 attr,
> +			       int channel, long *val)
> +{
> +	switch (type) {
> +	case hwmon_temp:
> +		return bcm54140_hwmon_read_temp(dev, attr, channel, val);
> +	case hwmon_in:
> +		return bcm54140_hwmon_read_in(dev, attr, channel, val);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static const char *const bcm54140_hwmon_in_labels[] = {
> +	"AVDDL",
> +	"AVDDH",
> +};
> +
> +static int bcm54140_hwmon_read_string(struct device *dev,
> +				      enum hwmon_sensor_types type, u32 attr,
> +				      int channel, const char **str)
> +{
> +	switch (type) {
> +	case hwmon_in:
> +		switch (attr) {
> +		case hwmon_in_label:
> +			*str = bcm54140_hwmon_in_labels[channel];
> +			return 0;
> +		default:
> +			return -EOPNOTSUPP;
> +		}
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static int bcm54140_hwmon_write_temp(struct device *dev, u32 attr,
> +				     int channel, long val)
> +{
> +	struct phy_device *phydev = dev_get_drvdata(dev);
> +	u16 mask = BCM54140_RDB_MON_TEMP_DATA_MASK;
> +	u16 reg;
> +
> +	val = clamp_val(val, BCM54140_HWMON_TO_TEMP(mask),
> +			BCM54140_HWMON_TO_TEMP(0));
> +
> +	switch (attr) {
> +	case hwmon_temp_min:
> +		reg = BCM54140_RDB_MON_TEMP_MIN;
> +		break;
> +	case hwmon_temp_max:
> +		reg = BCM54140_RDB_MON_TEMP_MAX;
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	return bcm_phy_modify_rdb(phydev, reg, mask,
> +				  BCM54140_HWMON_FROM_TEMP(val));
> +}
> +
> +static int bcm54140_hwmon_write_in(struct device *dev, u32 attr,
> +				   int channel, long val)
> +{
> +	struct phy_device *phydev = dev_get_drvdata(dev);
> +	u16 mask = BCM54140_HWMON_IN_MASK(channel);
> +	u16 reg;
> +
> +	val = clamp_val(val, 0, BCM54140_HWMON_TO_IN(channel, mask));
> +
> +	switch (attr) {
> +	case hwmon_in_min:
> +		reg = BCM54140_HWMON_IN_MIN_REG(channel);
> +		break;
> +	case hwmon_in_max:
> +		reg = BCM54140_HWMON_IN_MAX_REG(channel);
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	return bcm_phy_modify_rdb(phydev, reg, mask,
> +				  BCM54140_HWMON_FROM_IN(channel, val));
> +}
> +
> +static int bcm54140_hwmon_write(struct device *dev,
> +				enum hwmon_sensor_types type, u32 attr,
> +				int channel, long val)
> +{
> +	switch (type) {
> +	case hwmon_temp:
> +		return bcm54140_hwmon_write_temp(dev, attr, channel, val);
> +	case hwmon_in:
> +		return bcm54140_hwmon_write_in(dev, attr, channel, val);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static const struct hwmon_channel_info *bcm54140_hwmon_info[] = {
> +	HWMON_CHANNEL_INFO(temp,
> +			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
> +			   HWMON_T_ALARM),
> +	HWMON_CHANNEL_INFO(in,
> +			   HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX |
> +			   HWMON_I_ALARM | HWMON_I_LABEL,
> +			   HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX |
> +			   HWMON_I_ALARM | HWMON_I_LABEL),
> +	NULL
> +};
> +
> +static const struct hwmon_ops bcm54140_hwmon_ops = {
> +	.is_visible = bcm54140_hwmon_is_visible,
> +	.read = bcm54140_hwmon_read,
> +	.read_string = bcm54140_hwmon_read_string,
> +	.write = bcm54140_hwmon_write,
> +};
> +
> +static const struct hwmon_chip_info bcm54140_chip_info = {
> +	.ops = &bcm54140_hwmon_ops,
> +	.info = bcm54140_hwmon_info,
>  };
>  
>  static int bcm54140_phy_base_read_rdb(struct phy_device *phydev, u16 rdb)
> @@ -203,6 +522,72 @@ static int bcm54140_get_base_addr_and_port(struct phy_device *phydev)
>  	return 0;
>  }
>  
> +/* Check if one PHY has already done the init of the parts common to all PHYs
> + * in the Quad PHY package.
> + */
> +static bool bcm54140_is_pkg_init(struct phy_device *phydev)
> +{
> +	struct bcm54140_phy_priv *priv = phydev->priv;
> +	struct mii_bus *bus = phydev->mdio.bus;
> +	int base_addr = priv->base_addr;
> +	struct phy_device *phy;
> +	int i;
> +
> +	/* Quad PHY */
> +	for (i = 0; i < 4; i++) {
> +		phy = mdiobus_get_phy(bus, base_addr + i);
> +		if (!phy)
> +			continue;
> +
> +		if ((phy->phy_id & phydev->drv->phy_id_mask) !=
> +		    (phydev->drv->phy_id & phydev->drv->phy_id_mask))
> +			continue;
> +
> +		priv = phy->priv;
> +
> +		if (priv && priv->pkg_init)
> +			return true;
> +	}
> +
> +	return false;
> +}
> +
> +static int bcm54140_enable_monitoring(struct phy_device *phydev)
> +{
> +	u16 mask, set;
> +
> +	/* 3.3V voltage mode */
> +	set = BCM54140_RDB_MON_CTRL_V_MODE;
> +
> +	/* select round-robin */
> +	mask = BCM54140_RDB_MON_CTRL_SEL_MASK;
> +	set |= FIELD_PREP(BCM54140_RDB_MON_CTRL_SEL_MASK,
> +			  BCM54140_RDB_MON_CTRL_SEL_RR);
> +
> +	/* remove power-down bit */
> +	mask |= BCM54140_RDB_MON_CTRL_PWR_DOWN;
> +
> +	return bcm_phy_modify_rdb(phydev, BCM54140_RDB_MON_CTRL, mask, set);
> +}
> +
> +static int bcm54140_phy_probe_once(struct phy_device *phydev)
> +{
> +	struct device *hwmon;
> +	int ret;
> +
> +	/* enable hardware monitoring */
> +	ret = bcm54140_enable_monitoring(phydev);
> +	if (ret)
> +		return ret;
> +
> +	hwmon = devm_hwmon_device_register_with_info(&phydev->mdio.dev,
> +						     "BCM54140", phydev,
> +						     &bcm54140_chip_info,
> +						     NULL);
> +	return PTR_ERR_OR_ZERO(hwmon);
> +}
> +#endif
> +
>  static int bcm54140_phy_probe(struct phy_device *phydev)
>  {
>  	struct bcm54140_phy_priv *priv;
> @@ -218,6 +603,18 @@ static int bcm54140_phy_probe(struct phy_device *phydev)
>  	if (ret)
>  		return ret;
>  
> +#if IS_ENABLED(CONFIG_HWMON)
> +	mutex_init(&priv->alarm_lock);
> +
> +	if (!bcm54140_is_pkg_init(phydev)) {
> +		ret = bcm54140_phy_probe_once(phydev);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	priv->pkg_init = true;
> +#endif
> +
>  	dev_info(&phydev->mdio.dev,
>  		 "probed (port %d, base PHY address %d)\n",
>  		 priv->port, priv->base_addr);
> -- 
> 2.20.1
> 

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