On 3/25/19 4:00 AM, Charles Keepax wrote:
From: Lucas Tanure <tanureal@xxxxxxxxxxxxxxxxxxxxx>
Lochnagar is an evaluation and development board for Cirrus
Logic Smart CODEC and Amp devices. It allows the connection of
most Cirrus Logic devices on mini-cards, as well as allowing
connection of various application processor systems to provide a
full evaluation platform.
This driver adds support for the hardware monitoring features of
the Lochnagar 2 to the hwmon API. Monitoring is provided for
the board voltages, currents and temperature supported by the
board controller chip.
Signed-off-by: Lucas Tanure <tanureal@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
---
Changes since v1:
- Put includes into alphabetical order
- Remove lochnagar pointer and use regmap directly
- Add documentation and overflow protection on float conversion
- Tighten up delays on waiting for the reading to be available
- Drop current/voltage sensors from nano to micro volts/amps. The
hardware does not have sufficent accuracy for nano scale
measurements.
- Only take one sample for temperature readings as there is no
need to average the reading, temps should change slowly.
- Remove duplicated copyright notice since we already have the
SPDX header
Thanks,
Charles
Documentation/hwmon/lochnagar | 56 +++++++
MAINTAINERS | 3 +
drivers/hwmon/Kconfig | 10 ++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/lochnagar-hwmon.c | 315 ++++++++++++++++++++++++++++++++++++++++
5 files changed, 385 insertions(+)
create mode 100644 Documentation/hwmon/lochnagar
create mode 100644 drivers/hwmon/lochnagar-hwmon.c
diff --git a/Documentation/hwmon/lochnagar b/Documentation/hwmon/lochnagar
new file mode 100644
index 0000000000000..7b40b0fffc3e0
--- /dev/null
+++ b/Documentation/hwmon/lochnagar
@@ -0,0 +1,56 @@
+Kernel Driver Lochnagar
+========================
+
+Supported systems:
+ * Cirrus Logic : Lochnagar 2
+
+Author: Lucas A. Tanure Alves
+
+Description
+-----------
+
+Lochnagar 2 features built-in Current Monitor circuitry that allows for the
+measurement of both voltage and current on up to eight of the supply voltage
+rails provided to the minicards. The Current Monitor does not require any
+hardware modifications or external circuitry to operate.
+
+The current and voltage measurements are obtained through the standard register
+map interface to the Lochnagar board controller, and can therefore be monitored
+by software.
+
+Sysfs attributes
+----------------
+
+temp1_input The Lochnagar board temperature (milliCelsius).
+in0_input Measured voltage for DBVDD1 (microVolts)
+in0_label "DBVDD1"
+curr1_input Measured current for DBVDD1 (microAmps)
+curr1_label "DBVDD1"
+in1_input Measured voltage for 1V8 DSP (microVolts)
+in1_label "1V8 DSP"
+curr2_input Measured current for 1V8 DSP (microAmps)
+curr2_label "1V8 DSP"
+in2_input Measured voltage for 1V8 CDC (microVolts)
+in2_label "1V8 CDC"
+curr3_input Measured current for 1V8 CDC (microAmps)
+curr3_label "1V8 CDC"
+in3_input Measured voltage for VDDCORE DSP (microVolts)
+in3_label "VDDCORE DSP"
+curr4_input Measured current for VDDCORE DSP (microAmps)
+curr4_label "VDDCORE DSP"
+in4_input Measured voltage for AVDD 1V8 (microVolts)
+in4_label "AVDD 1V8"
+curr5_input Measured current for AVDD 1V8 (microAmps)
+curr5_label "AVDD 1V8"
+curr6_input Measured current for SYSVDD (microAmps)
+curr6_label "SYSVDD"
+in6_input Measured voltage for VDDCORE CDC (microVolts)
+in6_label "VDDCORE CDC"
+curr7_input Measured current for VDDCORE CDC (microAmps)
+curr7_label "VDDCORE CDC"
+in7_input Measured voltage for MICVDD (microVolts)
+in7_label "MICVDD"
+curr8_input Measured current for MICVDD (microAmps)
+curr8_label "MICVDD"
+
+Note: It is not possible to measure voltage on the SYSVDD rail.
diff --git a/MAINTAINERS b/MAINTAINERS
index e17ebf70b5480..4cd3c281d8b56 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3796,6 +3796,7 @@ M: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
L: patches@xxxxxxxxxxxxxxxxxxxxx
S: Supported
F: drivers/clk/clk-lochnagar.c
+F: drivers/hwmon/lochnagar-hwmon.c
F: drivers/mfd/lochnagar-i2c.c
F: drivers/pinctrl/cirrus/pinctrl-lochnagar.c
F: drivers/regulator/lochnagar-regulator.c
@@ -3804,8 +3805,10 @@ F: include/dt-bindings/pinctrl/lochnagar.h
F: include/linux/mfd/lochnagar*
F: Documentation/devicetree/bindings/mfd/cirrus,lochnagar.txt
F: Documentation/devicetree/bindings/clock/cirrus,lochnagar.txt
+F: Documentation/devicetree/bindings/hwmon/cirrus,lochnagar.txt
F: Documentation/devicetree/bindings/pinctrl/cirrus,lochnagar.txt
F: Documentation/devicetree/bindings/regulator/cirrus,lochnagar.txt
+F: Documentation/hwmon/lochnagar
CISCO FCOE HBA DRIVER
M: Satish Kharat <satishkh@xxxxxxxxx>
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index d0f1dfe2bcbbd..dedd5febd3aa6 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -705,6 +705,16 @@ config SENSORS_LINEAGE
This driver can also be built as a module. If so, the module
will be called lineage-pem.
+config SENSORS_LOCHNAGAR
+ tristate "Lochnagar Hardware Monitor"
+ depends on MFD_LOCHNAGAR
+ help
+ If you say yes here you get support for Lochnagar 2 temperature,
+ voltage and current sensors abilities.
+
+ This driver can also be built as a module. If so, the module
+ will be called lochnagar-hwmon.
+
config SENSORS_LTC2945
tristate "Linear Technology LTC2945"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index f5c7b442e69e5..8db472ea04f00 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -89,6 +89,7 @@ obj-$(CONFIG_SENSORS_JZ4740) += jz4740-hwmon.o
obj-$(CONFIG_SENSORS_K8TEMP) += k8temp.o
obj-$(CONFIG_SENSORS_K10TEMP) += k10temp.o
obj-$(CONFIG_SENSORS_LINEAGE) += lineage-pem.o
+obj-$(CONFIG_SENSORS_LOCHNAGAR) += lochnagar-hwmon.o
obj-$(CONFIG_SENSORS_LM63) += lm63.o
obj-$(CONFIG_SENSORS_LM70) += lm70.o
obj-$(CONFIG_SENSORS_LM73) += lm73.o
diff --git a/drivers/hwmon/lochnagar-hwmon.c b/drivers/hwmon/lochnagar-hwmon.c
new file mode 100644
index 0000000000000..cbd15adac7f37
--- /dev/null
+++ b/drivers/hwmon/lochnagar-hwmon.c
@@ -0,0 +1,315 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Lochnagar hardware monitoring features
+ *
+ * Copyright (c) 2016-2019 Cirrus Logic, Inc. and
+ * Cirrus Logic International Semiconductor Ltd.
+ *
+ * Author: Lucas Tanure <tanureal@xxxxxxxxxxxxxxxxxxxxx>
+ */
+
+#include <linux/delay.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/i2c.h>
+#include <linux/math64.h>
+#include <linux/mfd/lochnagar.h>
+#include <linux/mfd/lochnagar2_regs.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+struct lochnagar_hwmon {
+ struct regmap *regmap;
+
+ /* Lock to ensure only a single sensor is read at a time */
+ struct mutex sensor_lock;
+};
+
+enum lochnagar_measure_mode {
+ LN2_CURRENT = 0,
+ LN2_VOLTAGE,
+ LN2_TEMPERATURE,
+};
+
+static const char * const lochnagar_chan_names[] = {
+ "DBVDD1",
+ "1V8 DSP",
+ "1V8 CDC",
+ "VDDCORE DSP",
+ "AVDD 1V8",
+ "SYSVDD",
+ "VDDCORE CDC",
+ "MICVDD",
+};
+
+/**
+ * float_to_long - Convert ieee754 reading from hardware to an integer
+ *
+ * @data: Value read from the hardware
+ * @precision: Units to multiply up to eg. 1000 = milli, 1000000 = micro
+ *
+ * Return: Converted integer reading
+ *
+ * Depending on the measurement type the hardware returns an ieee754
+ * floating point value in either volts, amps or celsius. This function
+ * will convert that into an integer in a smaller unit such as micro-amps
The hwmon ABI says that voltages and current shall be reported in milli-units.
There is no option or means to report micro-units to userspace. A value of
1000 as reported to userspace means 1 Volt or 1 Ampere. Nothing else.
The above and the summary suggest that the intent here is to report units
to userspace in micro-units. This is against the ABI and not permitted.
Besides, if it takes 96 samples to read the current, an accuracy in uA has zero
value. Similar really applies to uV - it is hard to believe that any HW would be
able to return values with such an accuracy.
+ * or milli-celsius. The hardware does not return NaN, so consideration of
+ * that is not required.
+ */
+static long float_to_long(u32 data, u32 precision)
+{
+ u64 man = data & 0x007FFFFF;
+ int exp = ((data & 0x7F800000) >> 23) - 127 - 23;
+ bool negative = data & 0x80000000;
+ long result;
+
+ man = (man + (1 << 23)) * precision;
+
+ if (fls64(man) + exp > (int)sizeof(long) * 8 - 1)
+ result = LONG_MAX;
+ else if (exp < 0)
+ result = man >> -exp;
+ else
+ result = man << exp;
+
+ return negative ? -result : result;
+}
+
+static int do_measurement(struct regmap *regmap, int chan,
+ enum lochnagar_measure_mode mode, int nsamples)
+{
+ unsigned int val;
+ int ret;
+
+ chan = 1 << (chan + LOCHNAGAR2_IMON_MEASURED_CHANNELS_SHIFT);
+
+ ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL1,
+ LOCHNAGAR2_IMON_ENA_MASK | chan | mode);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL2, nsamples);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3,
+ LOCHNAGAR2_IMON_CONFIGURE_MASK);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL3, val,
+ val & LOCHNAGAR2_IMON_DONE_MASK,
+ 1000, 10000);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3,
+ LOCHNAGAR2_IMON_MEASURE_MASK);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * Actual measurement time is ~1.67mS per sample, approximate
+ * this with a 1.5mS per sample msleep and then poll for
+ * success upto ~0.17mS * 1023 (max nsamples). Normally for
up to
+ * smaller values of nsamples the poll will complete on the
+ * first loop due to other latency in the system.
+ */
+ msleep((nsamples * 2) - (nsamples / 2));
nsamples * 3 / 2 might be a bit easier to read.
+
+ ret = regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL3, val,
+ val & LOCHNAGAR2_IMON_DONE_MASK,
+ 5000, 200000);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3, 0);
+ if (ret < 0)
+ return ret;
+
+ return 0;
Why not just return the result of regmap_write() ?
+}
+
+static int request_data(struct regmap *regmap, int chan, u32 *data)
+{
+ unsigned int val;
+ int ret;
+
+ ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL4,
+ LOCHNAGAR2_IMON_DATA_REQ_MASK |
+ chan << LOCHNAGAR2_IMON_CH_SEL_SHIFT);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL4, val,
+ val & LOCHNAGAR2_IMON_DATA_RDY_MASK,
+ 1000, 10000);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_read(regmap, LOCHNAGAR2_IMON_DATA1, &val);
+ if (ret < 0)
+ return ret;
+
+ *data = val << 16;
+
+ ret = regmap_read(regmap, LOCHNAGAR2_IMON_DATA2, &val);
+ if (ret < 0)
+ return ret;
+
+ *data |= val;
+
+ ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL4, 0);
+ if (ret < 0)
+ return ret;
+
+ return 0;
return regmap_write() ?
+}
+
+static int read_sensor(struct device *dev, int chan,
+ enum lochnagar_measure_mode mode, int nsamples,
+ unsigned int precision, long *val)
+{
+ struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
+ struct regmap *regmap = priv->regmap;
+ u32 data;
+ int ret;
+
+ mutex_lock(&priv->sensor_lock);
+
+ ret = do_measurement(regmap, chan, mode, nsamples);
+ if (ret < 0) {
+ dev_err(dev, "Failed to perform measurement: %d\n", ret);
+ goto error;
+ }
+
+ ret = request_data(regmap, chan, &data);
+ if (ret < 0) {
+ dev_err(dev, "Failed to read measurement: %d\n", ret);
+ goto error;
+ }
+
+ *val = float_to_long(data, precision);
+
+error:
+ mutex_unlock(&priv->sensor_lock);
+
+ return ret;
+}
+
+static umode_t lochnagar_is_visible(const void *drvdata,
+ enum hwmon_sensor_types type,
+ u32 attr, int chan)
+{
+ if (type == hwmon_in && !strcmp("SYSVDD", lochnagar_chan_names[chan]))
+ return 0;
+
+ return 0444;
+}
+
+static int lochnagar_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int chan, long *val)
+{
+ switch (type) {
+ case hwmon_in:
+ return read_sensor(dev, chan, LN2_VOLTAGE, 1, 1000000, val);
+ case hwmon_curr:
+ return read_sensor(dev, chan, LN2_CURRENT, 96, 1000000, val);
+ case hwmon_temp:
+ return read_sensor(dev, chan, LN2_TEMPERATURE, 1, 1000, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int lochnagar_read_string(struct device *dev,
+ enum hwmon_sensor_types type, u32 attr,
+ int chan, const char **str)
+{
+ switch (type) {
+ case hwmon_in:
+ case hwmon_curr:
+ *str = lochnagar_chan_names[chan];
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static const struct hwmon_ops lochnagar_ops = {
+ .is_visible = lochnagar_is_visible,
+ .read = lochnagar_read,
+ .read_string = lochnagar_read_string,
+};
+
+static const struct hwmon_channel_info *lochnagar_info[] = {
+ HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
+ 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_INPUT | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LABEL),
+ 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_INPUT | HWMON_C_LABEL,
+ HWMON_C_INPUT | HWMON_C_LABEL,
+ HWMON_C_INPUT | HWMON_C_LABEL),
+ NULL
+};
+
+static const struct hwmon_chip_info lochnagar_chip_info = {
+ .ops = &lochnagar_ops,
+ .info = lochnagar_info,
+};
+
+static const struct of_device_id lochnagar_of_match[] = {
+ { .compatible = "cirrus,lochnagar2-hwmon" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, lochnagar_of_match);
+
+static int lochnagar_hwmon_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device *hwmon_dev;
+ struct lochnagar_hwmon *priv;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ mutex_init(&priv->sensor_lock);
+ priv->regmap = dev_get_regmap(dev->parent, NULL);
+ if (!priv->regmap) {
+ dev_err(dev, "No register map found\n");
+ return -EINVAL;
+ }
+
+ hwmon_dev = devm_hwmon_device_register_with_info(dev, "Lochnagar", priv,
+ &lochnagar_chip_info,
+ NULL);
+
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static struct platform_driver lochnagar_hwmon_driver = {
+ .driver = {
+ .name = "lochnagar-hwmon",
+ .of_match_table = lochnagar_of_match,
+ },
+ .probe = lochnagar_hwmon_probe,
+};
+module_platform_driver(lochnagar_hwmon_driver);
+
+MODULE_AUTHOR("Lucas Tanure <tanureal@xxxxxxxxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Lochnagar hardware monitoring features");
+MODULE_LICENSE("GPL");
