Re: [PATCH net-next v2 3/3] net: phy: bcm54140: add hwmon support

From: Guenter Roeck
Date: Sun Apr 19 2020 - 10:37:24 EST

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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@xxxxxxxx>
> ---
> 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@xxxxxxxxxxxx>

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@xxxxxxxx>
> +
> +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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