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Subject[PATCH v2 1/3] hwmon: adm1177: Add ADM1177 Hot Swap Controller and Digital Power Monitor driver
Date
ADM1177 is a Hot Swap Controller and Digital Power Monitor with
Soft Start Pin.

Datasheet:
Link: https://www.analog.com/media/en/technical-documentation/data-sheets/ADM1177.pdf

Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
---
Documentation/hwmon/adm1177.rst | 36 ++++
drivers/hwmon/Kconfig | 10 ++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/adm1177.c | 293 ++++++++++++++++++++++++++++++++
4 files changed, 340 insertions(+)
create mode 100644 Documentation/hwmon/adm1177.rst
create mode 100644 drivers/hwmon/adm1177.c

diff --git a/Documentation/hwmon/adm1177.rst b/Documentation/hwmon/adm1177.rst
new file mode 100644
index 000000000000..c81e0b4abd28
--- /dev/null
+++ b/Documentation/hwmon/adm1177.rst
@@ -0,0 +1,36 @@
+Kernel driver adm1177
+=====================
+
+Supported chips:
+ * Analog Devices ADM1177
+ Prefix: 'adm1177'
+ Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ADM1177.pdf
+
+Author: Beniamin Bia <beniamin.bia@analog.com>
+
+
+Description
+-----------
+
+This driver supports hardware monitoring for Analog Devices ADM1177
+Hot-Swap Controller and Digital Power Monitors with Soft Start Pin.
+
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate the
+devices explicitly. Please see Documentation/i2c/instantiating-devices for
+details.
+
+
+Sysfs entries
+-------------
+
+The following attributes are supported. Current maxim attribute
+is read-write, all other attributes are read-only.
+
+in0_input Measured voltage in microvolts.
+
+curr1_input Measured current in microamperes.
+curr1_max_alarm Overcurrent alarm in microamperes.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 5308c59d7001..3db8f5752675 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -164,6 +164,16 @@ config SENSORS_ADM1031
This driver can also be built as a module. If so, the module
will be called adm1031.

+config SENSORS_ADM1177
+ tristate "Analog Devices ADM1177 and compatibles"
+ depends on I2C
+ help
+ If you say yes here you get support for Analog Devices ADM1177
+ sensor chips.
+
+ This driver can also be built as a module. If so, the module
+ will be called adm1177.
+
config SENSORS_ADM9240
tristate "Analog Devices ADM9240 and compatibles"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 40c036ea45e6..27d04eab1be4 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_SENSORS_ADM1025) += adm1025.o
obj-$(CONFIG_SENSORS_ADM1026) += adm1026.o
obj-$(CONFIG_SENSORS_ADM1029) += adm1029.o
obj-$(CONFIG_SENSORS_ADM1031) += adm1031.o
+obj-$(CONFIG_SENSORS_ADM1177) += adm1177.o
obj-$(CONFIG_SENSORS_ADM9240) += adm9240.o
obj-$(CONFIG_SENSORS_ADS7828) += ads7828.o
obj-$(CONFIG_SENSORS_ADS7871) += ads7871.o
diff --git a/drivers/hwmon/adm1177.c b/drivers/hwmon/adm1177.c
new file mode 100644
index 000000000000..aaa9e17289f4
--- /dev/null
+++ b/drivers/hwmon/adm1177.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ADM1177 Hot Swap Controller and Digital Power Monitor with Soft Start Pin
+ *
+ * Copyright 2015-2019 Analog Devices Inc.
+ */
+
+#include <linux/bits.h>
+#include <linux/device.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+
+/* Command Byte Operations */
+#define ADM1177_CMD_V_CONT BIT(0)
+#define ADM1177_CMD_I_CONT BIT(2)
+#define ADM1177_CMD_VRANGE BIT(4)
+
+/* Extended Register */
+#define ADM1177_REG_ALERT_TH 2
+
+#define ADM1177_BITS 12
+
+/**
+ * struct adm1177_state - driver instance specific data
+ * @client pointer to i2c client
+ * @reg regulator info for the the power supply of the device
+ * @r_sense_uohm current sense resistor value
+ * @alert_threshold_ua current limit for shutdown
+ * @vrange_high internal voltage divider
+ */
+struct adm1177_state {
+ struct i2c_client *client;
+ struct regulator *reg;
+ u32 r_sense_uohm;
+ u32 alert_threshold_ua;
+ bool vrange_high;
+};
+
+static int adm1177_read_raw(struct adm1177_state *st, u8 num, u8 *data)
+{
+ return i2c_master_recv(st->client, data, num);
+}
+
+static int adm1177_write_cmd(struct adm1177_state *st, u8 cmd)
+{
+ return i2c_smbus_write_byte(st->client, cmd);
+}
+
+static int adm1177_write_alert_thr(struct adm1177_state *st,
+ u32 alert_threshold_ua)
+{
+ u64 val;
+ int ret;
+
+ val = 0xFFULL * alert_threshold_ua * st->r_sense_uohm;
+ val = div_u64(val, 105840000U);
+ val = div_u64(val, 1000U);
+ if (val > 0xFF) {
+ dev_warn(&st->client->dev,
+ "Requested shutdown current %d uA above limit\n",
+ alert_threshold_ua);
+
+ return -EINVAL;
+ }
+
+ ret = i2c_smbus_write_byte_data(st->client, ADM1177_REG_ALERT_TH,
+ val);
+ if (!ret)
+ return ret;
+
+ st->alert_threshold_ua = alert_threshold_ua;
+ return 0;
+}
+
+static int adm1177_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct adm1177_state *st = dev_get_drvdata(dev);
+ u8 data[3];
+ long dummy;
+ int ret;
+
+ switch (type) {
+ case hwmon_curr:
+ switch (attr) {
+ case hwmon_curr_input:
+ ret = adm1177_read_raw(st, 3, data);
+ if (ret < 0)
+ return ret;
+ dummy = (data[1] << 4) | (data[2] & 0xF);
+ /*
+ * convert to milliamperes
+ * ((105.84mV / 4096) x raw) / senseResistor(ohm)
+ */
+ *val = div_u64((105840000ull * dummy),
+ 4096 * st->r_sense_uohm);
+ return 0;
+ case hwmon_curr_max_alarm:
+ *val = st->alert_threshold_ua;
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+ case hwmon_in:
+ ret = adm1177_read_raw(st, 3, data);
+ if (ret < 0)
+ return ret;
+ dummy = (data[0] << 4) | (data[2] >> 4);
+ /*
+ * convert to millivolts based on resistor devision
+ * (V_fullscale / 4096) * raw
+ */
+ if (st->vrange_high)
+ dummy *= 26350;
+ else
+ dummy *= 6650;
+
+ *val = DIV_ROUND_CLOSEST(dummy, 4096);
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int adm1177_write(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long val)
+{
+ struct adm1177_state *st = dev_get_drvdata(dev);
+
+ switch (type) {
+ case hwmon_curr:
+ switch (attr) {
+ case hwmon_curr_max_alarm:
+ adm1177_write_alert_thr(st, val);
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static umode_t adm1177_is_visible(const void *data,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ const struct adm1177_state *st = data;
+
+ switch (type) {
+ case hwmon_in:
+ switch (attr) {
+ case hwmon_in_input:
+ return 0444;
+ }
+ break;
+ case hwmon_curr:
+ switch (attr) {
+ case hwmon_curr_input:
+ if (st->r_sense_uohm)
+ return 0444;
+ return 0;
+ case hwmon_curr_max_alarm:
+ if (st->r_sense_uohm)
+ return 0644;
+ return 0;
+ }
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
+static const struct hwmon_channel_info *adm1177_info[] = {
+ HWMON_CHANNEL_INFO(curr,
+ HWMON_C_INPUT | HWMON_C_MAX_ALARM),
+ HWMON_CHANNEL_INFO(in,
+ HWMON_I_INPUT),
+ NULL
+};
+
+static const struct hwmon_ops adm1177_hwmon_ops = {
+ .is_visible = adm1177_is_visible,
+ .read = adm1177_read,
+ .write = adm1177_write,
+};
+
+static const struct hwmon_chip_info adm1177_chip_info = {
+ .ops = &adm1177_hwmon_ops,
+ .info = adm1177_info,
+};
+
+static void adm1177_remove(void *data)
+{
+ struct adm1177_state *st = data;
+
+ regulator_disable(st->reg);
+}
+
+static int adm1177_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct device *hwmon_dev;
+ struct adm1177_state *st;
+ u32 alert_threshold_ua;
+ int ret;
+
+ st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
+ if (!st)
+ return -ENOMEM;
+
+ st->client = client;
+
+ st->reg = devm_regulator_get_optional(&client->dev, "vref");
+ if (IS_ERR(st->reg)) {
+ if (PTR_ERR(st->reg) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+
+ st->reg = NULL;
+ } else {
+ ret = regulator_enable(st->reg);
+ if (ret)
+ return ret;
+ ret = devm_add_action_or_reset(&client->dev, adm1177_remove,
+ st);
+ if (ret)
+ return ret;
+ }
+
+ if (device_property_read_u32(dev, "shunt-resistor-micro-ohms",
+ &st->r_sense_uohm))
+ st->r_sense_uohm = 0;
+ if (device_property_read_u32(dev, "adi,shutdown-threshold-microamp",
+ &alert_threshold_ua)) {
+ if (st->r_sense_uohm)
+ /*
+ * set maximum default value from datasheet based on
+ * shunt-resistor
+ */
+ alert_threshold_ua = div_u64(105840000000,
+ st->r_sense_uohm);
+ else
+ alert_threshold_ua = 0;
+ }
+ st->vrange_high = device_property_read_bool(dev,
+ "adi,vrange-high-enable");
+ if (alert_threshold_ua && st->r_sense_uohm)
+ adm1177_write_alert_thr(st, alert_threshold_ua);
+
+ ret = adm1177_write_cmd(st, ADM1177_CMD_V_CONT |
+ ADM1177_CMD_I_CONT |
+ (st->vrange_high ? 0 : ADM1177_CMD_VRANGE));
+ if (ret)
+ return ret;
+
+ hwmon_dev =
+ devm_hwmon_device_register_with_info(dev, client->name, st,
+ &adm1177_chip_info, NULL);
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id adm1177_id[] = {
+ {"adm1177", 0},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, adm1177_id);
+
+static const struct of_device_id adm1177_dt_ids[] = {
+ { .compatible = "adi,adm1177" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, adm1177_dt_ids);
+
+static struct i2c_driver adm1177_driver = {
+ .class = I2C_CLASS_HWMON,
+ .driver = {
+ .name = "adm1177",
+ .of_match_table = adm1177_dt_ids,
+ },
+ .probe = adm1177_probe,
+ .id_table = adm1177_id,
+};
+module_i2c_driver(adm1177_driver);
+
+MODULE_AUTHOR("Beniamin Bia <beniamin.bia@analog.com>");
+MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
+MODULE_DESCRIPTION("Analog Devices ADM1177 ADC driver");
+MODULE_LICENSE("GPL v2");
--
2.17.1
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