hwmon: (menf21bmc) Introduce MEN14F021P00 BMC HWMON driver

Added driver to support the 14F021P00 BMC Hardware Monitoring.
The BMC is a Board Management Controller including monitoring of the
board voltages.

Signed-off-by: Andreas Werner <andreas.werner@men.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

4 files changed, 291 insertions, 0 deletions

diff --git a/Documentation/hwmon/menf21bmc b/Documentation/hwmon/menf21bmc
new file mode 100644
index 000000000000..2a273a065c5e
--- /dev/null
+++ b/Documentation/hwmon/menf21bmc
@@ -0,0 +1,50 @@
+Kernel driver menf21bmc_hwmon
+=============================
+
+Supported chips:
+        * MEN 14F021P00
+          Prefix: 'menf21bmc_hwmon'
+          Adresses scanned: -
+
+Author: Andreas Werner <andreas.werner@men.de>
+
+Description
+-----------
+
+The menf21bmc is a Board Management Controller (BMC) which provides an I2C
+interface to the host to access the features implemented in the BMC.
+
+This driver gives access to the voltage monitoring feature of the main
+voltages of the board.
+The voltage sensors are connected to the ADC inputs of the BMC which is
+a PIC16F917 Mikrocontroller.
+
+Usage Notes
+-----------
+
+This driver is part of the MFD driver named "menf21bmc" and does
+not auto-detect devices.
+You will have to instantiate the MFD driver explicitly.
+Please see Documentation/i2c/instantiating-devices for
+details.
+
+Sysfs entries
+-------------
+
+The following attributes are supported. All attributes are read only
+The Limits are read once by the driver.
+
+in0_input       +3.3V input voltage
+in1_input       +5.0V input voltage
+in2_input       +12.0V input voltage
+in3_input       +5V Standby input voltage
+in4_input       VBAT (on board battery)
+
+in[0-4]_min     Minimum voltage limit
+in[0-4]_max     Maximum voltage limit
+
+in0_label       "MON_3_3V"
+in1_label       "MON_5V"
+in2_label       "MON_12V"
+in3_label       "5V_STANDBY"
+in4_label       "VBAT"
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index f00d048aa583..c08d172bbab4 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -839,6 +839,16 @@ config SENSORS_MCP3021
           This driver can also be built as a module.  If so, the module
           will be called mcp3021.
 
+config SENSORS_MENF21BMC_HWMON
+        tristate "MEN 14F021P00 BMC Hardware Monitoring"
+        depends on MFD_MENF21BMC
+        help
+          Say Y here to include support for the MEN 14F021P00 BMC
+          hardware monitoring.
+
+          This driver can also be built as a module. If so the module
+          will be called menf21bmc_hwmon.
+
 config SENSORS_ADCXX
         tristate "National Semiconductor ADCxxxSxxx"
         depends on SPI_MASTER
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index be28152c9848..c90a7611efaa 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -115,6 +115,7 @@ obj-$(CONFIG_SENSORS_MAX6650)	+= max6650.o
 obj-$(CONFIG_SENSORS_MAX6697)   += max6697.o
 obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
 obj-$(CONFIG_SENSORS_MCP3021)   += mcp3021.o
+obj-$(CONFIG_SENSORS_MENF21BMC_HWMON) += menf21bmc_hwmon.o
 obj-$(CONFIG_SENSORS_NCT6683)   += nct6683.o
 obj-$(CONFIG_SENSORS_NCT6775)   += nct6775.o
 obj-$(CONFIG_SENSORS_NTC_THERMISTOR)    += ntc_thermistor.o
diff --git a/drivers/hwmon/menf21bmc_hwmon.c b/drivers/hwmon/menf21bmc_hwmon.c
new file mode 100644
index 000000000000..c92229d321c9
--- /dev/null
+++ b/drivers/hwmon/menf21bmc_hwmon.c
@@ -0,0 +1,230 @@
+/*
+ *  MEN 14F021P00 Board Management Controller (BMC) hwmon driver.
+ *
+ *  This is the core hwmon driver of the MEN 14F021P00 BMC.
+ *  The BMC monitors the board voltages which can be access with this
+ *  driver through sysfs.
+ *
+ *  Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH
+ *
+ *  This program is free software; you can redistribute  it and/or modify it
+ *  under  the terms of  the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the  License, or (at your
+ *  option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/jiffies.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+
+#define DRV_NAME  "menf21bmc_hwmon"
+
+#define BMC_VOLT_COUNT  5
+#define MENF21BMC_V33   0
+#define MENF21BMC_V5    1
+#define MENF21BMC_V12   2
+#define MENF21BMC_V5_SB 3
+#define MENF21BMC_VBAT  4
+
+#define IDX_TO_VOLT_MIN_CMD(idx) (0x40 + idx)
+#define IDX_TO_VOLT_MAX_CMD(idx) (0x50 + idx)
+#define IDX_TO_VOLT_INP_CMD(idx) (0x60 + idx)
+
+struct menf21bmc_hwmon {
+        bool valid;
+        struct i2c_client *i2c_client;
+        unsigned long last_update;
+        int in_val[BMC_VOLT_COUNT];
+        int in_min[BMC_VOLT_COUNT];
+        int in_max[BMC_VOLT_COUNT];
+};
+
+static const char *const input_names[] = {
+        [MENF21BMC_V33]         = "MON_3_3V",
+        [MENF21BMC_V5]          = "MON_5V",
+        [MENF21BMC_V12]         = "MON_12V",
+        [MENF21BMC_V5_SB]       = "5V_STANDBY",
+        [MENF21BMC_VBAT]        = "VBAT"
+};
+
+static struct menf21bmc_hwmon *menf21bmc_hwmon_update(struct device *dev)
+{
+        int i;
+        int val;
+        struct menf21bmc_hwmon *drv_data = dev_get_drvdata(dev);
+        struct menf21bmc_hwmon *data_ret = drv_data;
+
+        if (time_after(jiffies, drv_data->last_update + HZ)
+            || !drv_data->valid) {
+                for (i = 0; i < BMC_VOLT_COUNT; i++) {
+                        val = i2c_smbus_read_word_data(drv_data->i2c_client,
+                                                       IDX_TO_VOLT_INP_CMD(i));
+                        if (val < 0) {
+                                data_ret = ERR_PTR(val);
+                                goto abort;
+                        }
+                        drv_data->in_val[i] = val;
+                }
+                drv_data->last_update = jiffies;
+                drv_data->valid = true;
+        }
+abort:
+        return data_ret;
+}
+
+static int menf21bmc_hwmon_get_volt_limits(struct menf21bmc_hwmon *drv_data)
+{
+        int i, val;
+
+        for (i = 0; i < BMC_VOLT_COUNT; i++) {
+                val = i2c_smbus_read_word_data(drv_data->i2c_client,
+                                               IDX_TO_VOLT_MIN_CMD(i));
+                if (val < 0)
+                        return val;
+
+                drv_data->in_min[i] = val;
+
+                val = i2c_smbus_read_word_data(drv_data->i2c_client,
+                                               IDX_TO_VOLT_MAX_CMD(i));
+                if (val < 0)
+                        return val;
+
+                drv_data->in_max[i] = val;
+        }
+        return 0;
+}
+
+static ssize_t
+show_label(struct device *dev, struct device_attribute *devattr, char *buf)
+{
+        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+
+        return sprintf(buf, "%s\n", input_names[attr->index]);
+}
+
+static ssize_t
+show_in(struct device *dev, struct device_attribute *devattr, char *buf)
+{
+        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+        struct menf21bmc_hwmon *drv_data = menf21bmc_hwmon_update(dev);
+
+        if (IS_ERR(drv_data))
+                return PTR_ERR(drv_data);
+
+        return sprintf(buf, "%d\n", drv_data->in_val[attr->index]);
+}
+
+static ssize_t
+show_min(struct device *dev, struct device_attribute *devattr, char *buf)
+{
+        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+        struct menf21bmc_hwmon *drv_data = dev_get_drvdata(dev);
+
+        return sprintf(buf, "%d\n", drv_data->in_min[attr->index]);
+}
+
+static ssize_t
+show_max(struct device *dev, struct device_attribute *devattr, char *buf)
+{
+        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+        struct menf21bmc_hwmon *drv_data = dev_get_drvdata(dev);
+
+        return sprintf(buf, "%d\n", drv_data->in_max[attr->index]);
+}
+
+#define create_voltage_sysfs(idx)                       \
+static SENSOR_DEVICE_ATTR(in##idx##_input, S_IRUGO,     \
+                        show_in, NULL, idx);            \
+static SENSOR_DEVICE_ATTR(in##idx##_min, S_IRUGO,       \
+                        show_min, NULL, idx);           \
+static SENSOR_DEVICE_ATTR(in##idx##_max, S_IRUGO,       \
+                        show_max, NULL, idx);           \
+static SENSOR_DEVICE_ATTR(in##idx##_label, S_IRUGO,     \
+                        show_label, NULL, idx);
+
+create_voltage_sysfs(0);
+create_voltage_sysfs(1);
+create_voltage_sysfs(2);
+create_voltage_sysfs(3);
+create_voltage_sysfs(4);
+
+static struct attribute *menf21bmc_hwmon_attrs[] = {
+        &sensor_dev_attr_in0_input.dev_attr.attr,
+        &sensor_dev_attr_in0_min.dev_attr.attr,
+        &sensor_dev_attr_in0_max.dev_attr.attr,
+        &sensor_dev_attr_in0_label.dev_attr.attr,
+
+        &sensor_dev_attr_in1_input.dev_attr.attr,
+        &sensor_dev_attr_in1_min.dev_attr.attr,
+        &sensor_dev_attr_in1_max.dev_attr.attr,
+        &sensor_dev_attr_in1_label.dev_attr.attr,
+
+        &sensor_dev_attr_in2_input.dev_attr.attr,
+        &sensor_dev_attr_in2_min.dev_attr.attr,
+        &sensor_dev_attr_in2_max.dev_attr.attr,
+        &sensor_dev_attr_in2_label.dev_attr.attr,
+
+        &sensor_dev_attr_in3_input.dev_attr.attr,
+        &sensor_dev_attr_in3_min.dev_attr.attr,
+        &sensor_dev_attr_in3_max.dev_attr.attr,
+        &sensor_dev_attr_in3_label.dev_attr.attr,
+
+        &sensor_dev_attr_in4_input.dev_attr.attr,
+        &sensor_dev_attr_in4_min.dev_attr.attr,
+        &sensor_dev_attr_in4_max.dev_attr.attr,
+        &sensor_dev_attr_in4_label.dev_attr.attr,
+        NULL
+};
+
+ATTRIBUTE_GROUPS(menf21bmc_hwmon);
+
+static int menf21bmc_hwmon_probe(struct platform_device *pdev)
+{
+        int ret;
+        struct menf21bmc_hwmon *drv_data;
+        struct i2c_client *i2c_client = to_i2c_client(pdev->dev.parent);
+        struct device *hwmon_dev;
+
+        drv_data = devm_kzalloc(&pdev->dev, sizeof(struct menf21bmc_hwmon),
+                                GFP_KERNEL);
+        if (!drv_data)
+                return -ENOMEM;
+
+        drv_data->i2c_client = i2c_client;
+
+        ret = menf21bmc_hwmon_get_volt_limits(drv_data);
+        if (ret) {
+                dev_err(&pdev->dev, "failed to read sensor limits");
+                return ret;
+        }
+
+        hwmon_dev = devm_hwmon_device_register_with_groups(&pdev->dev,
+                                                   "menf21bmc", drv_data,
+                                                   menf21bmc_hwmon_groups);
+        if (IS_ERR(hwmon_dev))
+                return PTR_ERR(hwmon_dev);
+
+        dev_info(&pdev->dev, "MEN 14F021P00 BMC hwmon device enabled");
+
+        return 0;
+}
+
+static struct platform_driver menf21bmc_hwmon = {
+        .probe          = menf21bmc_hwmon_probe,
+        .driver         = {
+                .name           = DRV_NAME,
+                .owner          = THIS_MODULE,
+        },
+};
+
+module_platform_driver(menf21bmc_hwmon);
+
+MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
+MODULE_DESCRIPTION("MEN 14F021P00 BMC hwmon");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:menf21bmc_hwmon");