hwmon: Versatile Express hwmon driver

hwmon framework driver for Versatile Express sensors, providing
information about board level voltage (only when regulator driver
is not configured), currents, temperature and power/energy usage.
Labels for the values can be defined as DT properties.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>

3 files changed, 238 insertions, 0 deletions

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index c4633de64465..db213fe958a5 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1197,6 +1197,14 @@ config SENSORS_TWL4030_MADC
         This driver can also be built as a module. If so it will be called
         twl4030-madc-hwmon.
 
+config SENSORS_VEXPRESS
+        tristate "Versatile Express"
+        depends on VEXPRESS_CONFIG
+        help
+          This driver provides support for hardware sensors available on
+          the ARM Ltd's Versatile Express platform. It can provide wide
+          range of information like temperature, power, energy.
+
 config SENSORS_VIA_CPUTEMP
         tristate "VIA CPU temperature sensor"
         depends on X86
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 8d5fcb5e8e9f..aac8b7c619d6 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -121,6 +121,7 @@ obj-$(CONFIG_SENSORS_TMP102)	+= tmp102.o
 obj-$(CONFIG_SENSORS_TMP401)    += tmp401.o
 obj-$(CONFIG_SENSORS_TMP421)    += tmp421.o
 obj-$(CONFIG_SENSORS_TWL4030_MADC)+= twl4030-madc-hwmon.o
+obj-$(CONFIG_SENSORS_VEXPRESS)  += vexpress.o
 obj-$(CONFIG_SENSORS_VIA_CPUTEMP)+= via-cputemp.o
 obj-$(CONFIG_SENSORS_VIA686A)   += via686a.o
 obj-$(CONFIG_SENSORS_VT1211)    += vt1211.o
diff --git a/drivers/hwmon/vexpress.c b/drivers/hwmon/vexpress.c
new file mode 100644
index 000000000000..59fd1268e58a
--- /dev/null
+++ b/drivers/hwmon/vexpress.c
@@ -0,0 +1,229 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2012 ARM Limited
+ */
+
+#define DRVNAME "vexpress-hwmon"
+#define pr_fmt(fmt) DRVNAME ": " fmt
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/vexpress.h>
+
+struct vexpress_hwmon_data {
+        struct device *hwmon_dev;
+        struct vexpress_config_func *func;
+};
+
+static ssize_t vexpress_hwmon_name_show(struct device *dev,
+                struct device_attribute *dev_attr, char *buffer)
+{
+        const char *compatible = of_get_property(dev->of_node, "compatible",
+                        NULL);
+
+        return sprintf(buffer, "%s\n", compatible);
+}
+
+static ssize_t vexpress_hwmon_label_show(struct device *dev,
+                struct device_attribute *dev_attr, char *buffer)
+{
+        const char *label = of_get_property(dev->of_node, "label", NULL);
+
+        if (!label)
+                return -ENOENT;
+
+        return snprintf(buffer, PAGE_SIZE, "%s\n", label);
+}
+
+static ssize_t vexpress_hwmon_u32_show(struct device *dev,
+                struct device_attribute *dev_attr, char *buffer)
+{
+        struct vexpress_hwmon_data *data = dev_get_drvdata(dev);
+        int err;
+        u32 value;
+
+        err = vexpress_config_read(data->func, 0, &value);
+        if (err)
+                return err;
+
+        return snprintf(buffer, PAGE_SIZE, "%u\n", value /
+                        to_sensor_dev_attr(dev_attr)->index);
+}
+
+static ssize_t vexpress_hwmon_u64_show(struct device *dev,
+                struct device_attribute *dev_attr, char *buffer)
+{
+        struct vexpress_hwmon_data *data = dev_get_drvdata(dev);
+        int err;
+        u32 value_hi, value_lo;
+
+        err = vexpress_config_read(data->func, 0, &value_lo);
+        if (err)
+                return err;
+
+        err = vexpress_config_read(data->func, 1, &value_hi);
+        if (err)
+                return err;
+
+        return snprintf(buffer, PAGE_SIZE, "%llu\n",
+                        div_u64(((u64)value_hi << 32) | value_lo,
+                        to_sensor_dev_attr(dev_attr)->index));
+}
+
+static DEVICE_ATTR(name, S_IRUGO, vexpress_hwmon_name_show, NULL);
+
+#define VEXPRESS_HWMON_ATTRS(_name, _label_attr, _input_attr)   \
+struct attribute *vexpress_hwmon_attrs_##_name[] = {            \
+        &dev_attr_name.attr,                                    \
+        &dev_attr_##_label_attr.attr,                           \
+        &sensor_dev_attr_##_input_attr.dev_attr.attr,           \
+        NULL                                                    \
+}
+
+#if !defined(CONFIG_REGULATOR_VEXPRESS)
+static DEVICE_ATTR(in1_label, S_IRUGO, vexpress_hwmon_label_show, NULL);
+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, vexpress_hwmon_u32_show,
+                NULL, 1000);
+static VEXPRESS_HWMON_ATTRS(volt, in1_label, in1_input);
+static struct attribute_group vexpress_hwmon_group_volt = {
+        .attrs = vexpress_hwmon_attrs_volt,
+};
+#endif
+
+static DEVICE_ATTR(curr1_label, S_IRUGO, vexpress_hwmon_label_show, NULL);
+static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, vexpress_hwmon_u32_show,
+                NULL, 1000);
+static VEXPRESS_HWMON_ATTRS(amp, curr1_label, curr1_input);
+static struct attribute_group vexpress_hwmon_group_amp = {
+        .attrs = vexpress_hwmon_attrs_amp,
+};
+
+static DEVICE_ATTR(temp1_label, S_IRUGO, vexpress_hwmon_label_show, NULL);
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, vexpress_hwmon_u32_show,
+                NULL, 1000);
+static VEXPRESS_HWMON_ATTRS(temp, temp1_label, temp1_input);
+static struct attribute_group vexpress_hwmon_group_temp = {
+        .attrs = vexpress_hwmon_attrs_temp,
+};
+
+static DEVICE_ATTR(power1_label, S_IRUGO, vexpress_hwmon_label_show, NULL);
+static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, vexpress_hwmon_u32_show,
+                NULL, 1);
+static VEXPRESS_HWMON_ATTRS(power, power1_label, power1_input);
+static struct attribute_group vexpress_hwmon_group_power = {
+        .attrs = vexpress_hwmon_attrs_power,
+};
+
+static DEVICE_ATTR(energy1_label, S_IRUGO, vexpress_hwmon_label_show, NULL);
+static SENSOR_DEVICE_ATTR(energy1_input, S_IRUGO, vexpress_hwmon_u64_show,
+                NULL, 1);
+static VEXPRESS_HWMON_ATTRS(energy, energy1_label, energy1_input);
+static struct attribute_group vexpress_hwmon_group_energy = {
+        .attrs = vexpress_hwmon_attrs_energy,
+};
+
+static struct of_device_id vexpress_hwmon_of_match[] = {
+#if !defined(CONFIG_REGULATOR_VEXPRESS)
+        {
+                .compatible = "arm,vexpress-volt",
+                .data = &vexpress_hwmon_group_volt,
+        },
+#endif
+        {
+                .compatible = "arm,vexpress-amp",
+                .data = &vexpress_hwmon_group_amp,
+        }, {
+                .compatible = "arm,vexpress-temp",
+                .data = &vexpress_hwmon_group_temp,
+        }, {
+                .compatible = "arm,vexpress-power",
+                .data = &vexpress_hwmon_group_power,
+        }, {
+                .compatible = "arm,vexpress-energy",
+                .data = &vexpress_hwmon_group_energy,
+        },
+        {}
+};
+MODULE_DEVICE_TABLE(of, vexpress_hwmon_of_match);
+
+static int vexpress_hwmon_probe(struct platform_device *pdev)
+{
+        int err;
+        const struct of_device_id *match;
+        struct vexpress_hwmon_data *data;
+
+        data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+        if (!data)
+                return -ENOMEM;
+        platform_set_drvdata(pdev, data);
+
+        match = of_match_device(vexpress_hwmon_of_match, &pdev->dev);
+        if (!match)
+                return -ENODEV;
+
+        data->func = vexpress_config_func_get_by_dev(&pdev->dev);
+        if (!data->func)
+                return -ENODEV;
+
+        err = sysfs_create_group(&pdev->dev.kobj, match->data);
+        if (err)
+                goto error;
+
+        data->hwmon_dev = hwmon_device_register(&pdev->dev);
+        if (IS_ERR(data->hwmon_dev)) {
+                err = PTR_ERR(data->hwmon_dev);
+                goto error;
+        }
+
+        return 0;
+
+error:
+        sysfs_remove_group(&pdev->dev.kobj, match->data);
+        vexpress_config_func_put(data->func);
+        return err;
+}
+
+static int __devexit vexpress_hwmon_remove(struct platform_device *pdev)
+{
+        struct vexpress_hwmon_data *data = platform_get_drvdata(pdev);
+        const struct of_device_id *match;
+
+        hwmon_device_unregister(data->hwmon_dev);
+
+        match = of_match_device(vexpress_hwmon_of_match, &pdev->dev);
+        sysfs_remove_group(&pdev->dev.kobj, match->data);
+
+        vexpress_config_func_put(data->func);
+
+        return 0;
+}
+
+static struct platform_driver vexpress_hwmon_driver = {
+        .probe = vexpress_hwmon_probe,
+        .remove = __devexit_p(vexpress_hwmon_remove),
+        .driver = {
+                .name = DRVNAME,
+                .owner = THIS_MODULE,
+                .of_match_table = vexpress_hwmon_of_match,
+        },
+};
+
+module_platform_driver(vexpress_hwmon_driver);
+
+MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
+MODULE_DESCRIPTION("Versatile Express hwmon sensors driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:vexpress-hwmon");