/*
 * IBM PowerNV platform sensors for temperature/fan/voltage/power
 * Copyright (C) 2014 IBM
 *
 * 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.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.
 */

#define DRVNAME         "ibmpowernv"
#define pr_fmt(fmt)     DRVNAME ": " fmt

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/of.h>
#include <linux/slab.h>

#include <linux/platform_device.h>
#include <asm/opal.h>
#include <linux/err.h>
#include <asm/cputhreads.h>
#include <asm/smp.h>

#define MAX_ATTR_LEN    32
#define MAX_LABEL_LEN   64

/* Sensor suffix name from DT */
#define DT_FAULT_ATTR_SUFFIX            "faulted"
#define DT_DATA_ATTR_SUFFIX             "data"
#define DT_THRESHOLD_ATTR_SUFFIX        "thrs"

/*
 * Enumerates all the types of sensors in the POWERNV platform and does index
 * into 'struct sensor_group'
 */
enum sensors {
        FAN,
        TEMP,
        POWER_SUPPLY,
        POWER_INPUT,
        MAX_SENSOR_TYPE,
};

#define INVALID_INDEX (-1U)

static struct sensor_group {
        const char *name;
        const char *compatible;
        struct attribute_group group;
        u32 attr_count;
        u32 hwmon_index;
} sensor_groups[] = {
        {"fan", "ibm,opal-sensor-cooling-fan"},
        {"temp", "ibm,opal-sensor-amb-temp"},
        {"in", "ibm,opal-sensor-power-supply"},
        {"power", "ibm,opal-sensor-power"}
};

struct sensor_data {
        u32 id; /* An opaque id of the firmware for each sensor */
        u32 hwmon_index;
        u32 opal_index;
        enum sensors type;
        char label[MAX_LABEL_LEN];
        char name[MAX_ATTR_LEN];
        struct device_attribute dev_attr;
};

struct platform_data {
        const struct attribute_group *attr_groups[MAX_SENSOR_TYPE + 1];
        u32 sensors_count; /* Total count of sensors from each group */
};

static ssize_t show_sensor(struct device *dev, struct device_attribute *devattr,
                           char *buf)
{
        struct sensor_data *sdata = container_of(devattr, struct sensor_data,
                                                 dev_attr);
        ssize_t ret;
        u32 x;

        ret = opal_get_sensor_data(sdata->id, &x);
        if (ret)
                return ret;

        /* Convert temperature to milli-degrees */
        if (sdata->type == TEMP)
                x *= 1000;
        /* Convert power to micro-watts */
        else if (sdata->type == POWER_INPUT)
                x *= 1000000;

        return sprintf(buf, "%u\n", x);
}

static ssize_t show_label(struct device *dev, struct device_attribute *devattr,
                          char *buf)
{
        struct sensor_data *sdata = container_of(devattr, struct sensor_data,
                                                 dev_attr);

        return sprintf(buf, "%s\n", sdata->label);
}

static int __init get_logical_cpu(int hwcpu)
{
        int cpu;

        for_each_possible_cpu(cpu)
                if (get_hard_smp_processor_id(cpu) == hwcpu)
                        return cpu;

        return -ENOENT;
}

static void __init make_sensor_label(struct device_node *np,
                                     struct sensor_data *sdata,
                                     const char *label)
{
        u32 id;
        size_t n;

        n = snprintf(sdata->label, sizeof(sdata->label), "%s", label);

        /*
         * Core temp pretty print
         */
        if (!of_property_read_u32(np, "ibm,pir", &id)) {
                int cpuid = get_logical_cpu(id);

                if (cpuid >= 0)
                        /*
                         * The digital thermal sensors are associated
                         * with a core. Let's print out the range of
                         * cpu ids corresponding to the hardware
                         * threads of the core.
                         */
                        n += snprintf(sdata->label + n,
                                      sizeof(sdata->label) - n, " %d-%d",
                                      cpuid, cpuid + threads_per_core - 1);
                else
                        n += snprintf(sdata->label + n,
                                      sizeof(sdata->label) - n, " phy%d", id);
        }

        /*
         * Membuffer pretty print
         */
        if (!of_property_read_u32(np, "ibm,chip-id", &id))
                n += snprintf(sdata->label + n, sizeof(sdata->label) - n,
                              " %d", id & 0xffff);
}

static int get_sensor_index_attr(const char *name, u32 *index, char *attr)
{
        char *hash_pos = strchr(name, '#');
        char buf[8] = { 0 };
        char *dash_pos;
        u32 copy_len;
        int err;

        if (!hash_pos)
                return -EINVAL;

        dash_pos = strchr(hash_pos, '-');
        if (!dash_pos)
                return -EINVAL;

        copy_len = dash_pos - hash_pos - 1;
        if (copy_len >= sizeof(buf))
                return -EINVAL;

        strncpy(buf, hash_pos + 1, copy_len);

        err = kstrtou32(buf, 10, index);
        if (err)
                return err;

        strncpy(attr, dash_pos + 1, MAX_ATTR_LEN);

        return 0;
}

static const char *convert_opal_attr_name(enum sensors type,
                                          const char *opal_attr)
{
        const char *attr_name = NULL;

        if (!strcmp(opal_attr, DT_FAULT_ATTR_SUFFIX)) {
                attr_name = "fault";
        } else if (!strcmp(opal_attr, DT_DATA_ATTR_SUFFIX)) {
                attr_name = "input";
        } else if (!strcmp(opal_attr, DT_THRESHOLD_ATTR_SUFFIX)) {
                if (type == TEMP)
                        attr_name = "max";
                else if (type == FAN)
                        attr_name = "min";
        }

        return attr_name;
}

/*
 * This function translates the DT node name into the 'hwmon' attribute name.
 * IBMPOWERNV device node appear like cooling-fan#2-data, amb-temp#1-thrs etc.
 * which need to be mapped as fan2_input, temp1_max respectively before
 * populating them inside hwmon device class.
 */
static const char *parse_opal_node_name(const char *node_name,
                                        enum sensors type, u32 *index)
{
        char attr_suffix[MAX_ATTR_LEN];
        const char *attr_name;
        int err;

        err = get_sensor_index_attr(node_name, index, attr_suffix);
        if (err)
                return ERR_PTR(err);

        attr_name = convert_opal_attr_name(type, attr_suffix);
        if (!attr_name)
                return ERR_PTR(-ENOENT);

        return attr_name;
}

static int get_sensor_type(struct device_node *np)
{
        enum sensors type;
        const char *str;

        for (type = 0; type < MAX_SENSOR_TYPE; type++) {
                if (of_device_is_compatible(np, sensor_groups[type].compatible))
                        return type;
        }

        /*
         * Let's check if we have a newer device tree
         */
        if (!of_device_is_compatible(np, "ibm,opal-sensor"))
                return MAX_SENSOR_TYPE;

        if (of_property_read_string(np, "sensor-type", &str))
                return MAX_SENSOR_TYPE;

        for (type = 0; type < MAX_SENSOR_TYPE; type++)
                if (!strcmp(str, sensor_groups[type].name))
                        return type;

        return MAX_SENSOR_TYPE;
}

static u32 get_sensor_hwmon_index(struct sensor_data *sdata,
                                  struct sensor_data *sdata_table, int count)
{
        int i;

        /*
         * We don't use the OPAL index on newer device trees
         */
        if (sdata->opal_index != INVALID_INDEX) {
                for (i = 0; i < count; i++)
                        if (sdata_table[i].opal_index == sdata->opal_index &&
                            sdata_table[i].type == sdata->type)
                                return sdata_table[i].hwmon_index;
        }
        return ++sensor_groups[sdata->type].hwmon_index;
}

static int populate_attr_groups(struct platform_device *pdev)
{
        struct platform_data *pdata = platform_get_drvdata(pdev);
        const struct attribute_group **pgroups = pdata->attr_groups;
        struct device_node *opal, *np;
        enum sensors type;

        opal = of_find_node_by_path("/ibm,opal/sensors");
        for_each_child_of_node(opal, np) {
                const char *label;

                if (np->name == NULL)
                        continue;

                type = get_sensor_type(np);
                if (type == MAX_SENSOR_TYPE)
                        continue;

                sensor_groups[type].attr_count++;

                /*
                 * add a new attribute for labels
                 */
                if (!of_property_read_string(np, "label", &label))
                        sensor_groups[type].attr_count++;
        }

        of_node_put(opal);

        for (type = 0; type < MAX_SENSOR_TYPE; type++) {
                sensor_groups[type].group.attrs = devm_kzalloc(&pdev->dev,
                                        sizeof(struct attribute *) *
                                        (sensor_groups[type].attr_count + 1),
                                        GFP_KERNEL);
                if (!sensor_groups[type].group.attrs)
                        return -ENOMEM;

                pgroups[type] = &sensor_groups[type].group;
                pdata->sensors_count += sensor_groups[type].attr_count;
                sensor_groups[type].attr_count = 0;
        }

        return 0;
}

static void create_hwmon_attr(struct sensor_data *sdata, const char *attr_name,
                              ssize_t (*show)(struct device *dev,
                                              struct device_attribute *attr,
                                              char *buf))
{
        snprintf(sdata->name, MAX_ATTR_LEN, "%s%d_%s",
                 sensor_groups[sdata->type].name, sdata->hwmon_index,
                 attr_name);

        sysfs_attr_init(&sdata->dev_attr.attr);
        sdata->dev_attr.attr.name = sdata->name;
        sdata->dev_attr.attr.mode = S_IRUGO;
        sdata->dev_attr.show = show;
}

/*
 * Iterate through the device tree for each child of 'sensors' node, create
 * a sysfs attribute file, the file is named by translating the DT node name
 * to the name required by the higher 'hwmon' driver like fan1_input, temp1_max
 * etc..
 */
static int create_device_attrs(struct platform_device *pdev)
{
        struct platform_data *pdata = platform_get_drvdata(pdev);
        const struct attribute_group **pgroups = pdata->attr_groups;
        struct device_node *opal, *np;
        struct sensor_data *sdata;
        u32 sensor_id;
        enum sensors type;
        u32 count = 0;
        int err = 0;

        opal = of_find_node_by_path("/ibm,opal/sensors");
        sdata = devm_kzalloc(&pdev->dev, pdata->sensors_count * sizeof(*sdata),
                             GFP_KERNEL);
        if (!sdata) {
                err = -ENOMEM;
                goto exit_put_node;
        }

        for_each_child_of_node(opal, np) {
                const char *attr_name;
                u32 opal_index;
                const char *label;

                if (np->name == NULL)
                        continue;

                type = get_sensor_type(np);
                if (type == MAX_SENSOR_TYPE)
                        continue;

                /*
                 * Newer device trees use a "sensor-data" property
                 * name for input.
                 */
                if (of_property_read_u32(np, "sensor-id", &sensor_id) &&
                    of_property_read_u32(np, "sensor-data", &sensor_id)) {
                        dev_info(&pdev->dev,
                                 "'sensor-id' missing in the node '%s'\n",
                                 np->name);
                        continue;
                }

                sdata[count].id = sensor_id;
                sdata[count].type = type;

                /*
                 * If we can not parse the node name, it means we are
                 * running on a newer device tree. We can just forget
                 * about the OPAL index and use a defaut value for the
                 * hwmon attribute name
                 */
                attr_name = parse_opal_node_name(np->name, type, &opal_index);
                if (IS_ERR(attr_name)) {
                        attr_name = "input";
                        opal_index = INVALID_INDEX;
                }

                sdata[count].opal_index = opal_index;
                sdata[count].hwmon_index =
                        get_sensor_hwmon_index(&sdata[count], sdata, count);

                create_hwmon_attr(&sdata[count], attr_name, show_sensor);

                pgroups[type]->attrs[sensor_groups[type].attr_count++] =
                                &sdata[count++].dev_attr.attr;

                if (!of_property_read_string(np, "label", &label)) {
                        /*
                         * For the label attribute, we can reuse the
                         * "properties" of the previous "input"
                         * attribute. They are related to the same
                         * sensor.
                         */
                        sdata[count].type = type;
                        sdata[count].opal_index = sdata[count - 1].opal_index;
                        sdata[count].hwmon_index = sdata[count - 1].hwmon_index;

                        make_sensor_label(np, &sdata[count], label);

                        create_hwmon_attr(&sdata[count], "label", show_label);

                        pgroups[type]->attrs[sensor_groups[type].attr_count++] =
                                &sdata[count++].dev_attr.attr;
                }
        }

exit_put_node:
        of_node_put(opal);
        return err;
}

static int ibmpowernv_probe(struct platform_device *pdev)
{
        struct platform_data *pdata;
        struct device *hwmon_dev;
        int err;

        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
        if (!pdata)
                return -ENOMEM;

        platform_set_drvdata(pdev, pdata);
        pdata->sensors_count = 0;
        err = populate_attr_groups(pdev);
        if (err)
                return err;

        /* Create sysfs attribute data for each sensor found in the DT */
        err = create_device_attrs(pdev);
        if (err)
                return err;

        /* Finally, register with hwmon */
        hwmon_dev = devm_hwmon_device_register_with_groups(&pdev->dev, DRVNAME,
                                                           pdata,
                                                           pdata->attr_groups);

        return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct platform_device_id opal_sensor_driver_ids[] = {
        {
                .name = "opal-sensor",
        },
        { }
};
MODULE_DEVICE_TABLE(platform, opal_sensor_driver_ids);

static const struct of_device_id opal_sensor_match[] = {
        { .compatible   = "ibm,opal-sensor" },
        { },
};
MODULE_DEVICE_TABLE(of, opal_sensor_match);

static struct platform_driver ibmpowernv_driver = {
        .probe          = ibmpowernv_probe,
        .id_table       = opal_sensor_driver_ids,
        .driver         = {
                .owner  = THIS_MODULE,
                .name   = DRVNAME,
                .of_match_table = opal_sensor_match,
        },
};

module_platform_driver(ibmpowernv_driver);

MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
MODULE_DESCRIPTION("IBM POWERNV platform sensors");
MODULE_LICENSE("GPL");