Date:   Tue, 3 Dec 2019 15:57:09 +0200
From:   Beniamin Bia <beniamin.bia@...log.com>
To:     <linux-hwmon@...r.kernel.org>
CC:     <Michael.Hennerich@...log.com>, <linux-kernel@...r.kernel.org>,
        <jdelvare@...e.com>, <linux@...ck-us.net>, <mark.rutland@....com>,
        <lgirdwood@...il.com>, <broonie@...nel.org>,
        <devicetree@...r.kernel.org>, <biabeniamin@...look.com>,
        Beniamin Bia <beniamin.bia@...log.com>
Subject: [PATCH 1/3] hwmon: adm1177: Add ADM1177 Hot Swap Controller and Digital Power Monitor driver

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@...log.com>
---
 drivers/hwmon/Kconfig   |  10 ++
 drivers/hwmon/Makefile  |   1 +
 drivers/hwmon/adm1177.c | 274 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 285 insertions(+)
 create mode 100644 drivers/hwmon/adm1177.c

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..08950cecc9f9
--- /dev/null
+++ b/drivers/hwmon/adm1177.c
@@ -0,0 +1,274 @@
+// 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/module.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/regulator/consumer.h>
+
+/*  Command Byte Operations */
+#define ADM1177_CMD_V_CONT	BIT(0)
+#define ADM1177_CMD_V_ONCE	BIT(1)
+#define ADM1177_CMD_I_CONT	BIT(2)
+#define ADM1177_CMD_I_ONCE	BIT(3)
+#define ADM1177_CMD_VRANGE	BIT(4)
+#define ADM1177_CMD_STATUS_RD	BIT(6)
+
+/* Extended Register */
+#define ADM1177_REG_ALERT_EN	1
+#define ADM1177_REG_ALERT_TH	2
+#define ADM1177_REG_CONTROL	3
+
+/* ADM1177_REG_ALERT_EN */
+#define ADM1177_EN_ADC_OC1	BIT(0)
+#define ADM1177_EN_ADC_OC4	BIT(1)
+#define ADM1177_EN_HS_ALERT	BIT(2)
+#define ADM1177_EN_OFF_ALERT	BIT(3)
+#define ADM1177_CLEAR		BIT(4)
+
+/* ADM1177_REG_CONTROL */
+#define ADM1177_SWOFF		BIT(0)
+
+#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
+ * @command		internal control register
+ * @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;
+	u8			command;
+	u32			r_sense_uohm;
+	u32			alert_threshold_ua;
+	bool			vrange_high;
+};
+
+static int adm1177_read_raw(struct adm1177_state *st, u8 num, u8 *data)
+{
+	struct i2c_client *client = st->client;
+
+	return i2c_master_recv(client, data, num);
+}
+
+static int adm1177_write_cmd(struct adm1177_state *st, u8 cmd)
+{
+	st->command = cmd;
+	return i2c_smbus_write_byte(st->client, cmd);
+}
+
+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:
+		ret = adm1177_read_raw(st, 3, data);
+		if (ret < 0)
+			return ret;
+		dummy = (data[1] << 4) | (data[2] & 0xF);
+		/*
+		 * convert in milliamperes
+		 * ((105.84mV / 4096) x raw) / senseResistor(ohm)
+		 */
+		*val = div_u64((105840000ull * dummy), 4096 * st->r_sense_uohm);
+		return 0;
+	case hwmon_in:
+		ret = adm1177_read_raw(st, 3, data);
+		if (ret < 0)
+			return ret;
+		dummy = (data[0] << 4) | (data[2] >> 4);
+		/*
+		 * convert in millivolts based on resistor devision
+		 * (V_fullscale / 4096) * raw
+		 */
+		if (st->command & ADM1177_CMD_VRANGE)
+			*val = 6650;
+		else
+			*val = 26350;
+
+		*val = ((*val * dummy) / 4096);
+		return 0;
+	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;
+		}
+		break;
+	default:
+		break;
+	}
+	return 0;
+}
+
+static const u32 adm1177_curr_config[] = {
+	HWMON_C_INPUT,
+	0
+};
+
+static const struct hwmon_channel_info adm1177_curr = {
+	.type = hwmon_curr,
+	.config = adm1177_curr_config,
+};
+
+static const u32 adm1177_in_config[] = {
+	HWMON_I_INPUT,
+	0
+};
+
+static const struct hwmon_channel_info adm1177_in = {
+	.type = hwmon_in,
+	.config = adm1177_in_config,
+};
+
+static const struct hwmon_channel_info *adm1177_info[] = {
+	&adm1177_curr,
+	&adm1177_in,
+	NULL
+};
+
+static const struct hwmon_ops adm1177_hwmon_ops = {
+	.is_visible = adm1177_is_visible,
+	.read = adm1177_read,
+};
+
+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;
+	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, "adi,r-sense-micro-ohms",
+				     &st->r_sense_uohm))
+		st->r_sense_uohm = 1;
+	if (device_property_read_u32(dev, "adi,shutdown-threshold-microamp",
+				     &st->alert_threshold_ua))
+		st->alert_threshold_ua = 0;
+	st->vrange_high = device_property_read_bool(dev,
+						    "adi,vrange-high-enable");
+	if (st->alert_threshold_ua) {
+		u64 val;
+
+		val = (0xFFUL * st->alert_threshold_ua * st->r_sense_uohm);
+		val = div_u64(val, 105840000U);
+		if (val > 0xFF) {
+			dev_warn(&client->dev,
+				 "Requested shutdown current %d uA above limit\n",
+				 st->alert_threshold_ua);
+
+			val = 0xFF;
+		}
+		i2c_smbus_write_byte_data(st->client, ADM1177_REG_ALERT_TH,
+					  val);
+	}
+
+	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@...log.com>");
+MODULE_AUTHOR("Michael Hennerich <michael.hennerich@...log.com>");
+MODULE_DESCRIPTION("Analog Devices ADM1177 ADC driver");
+MODULE_LICENSE("GPL v2");
-- 
2.17.1

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