// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Hardware monitoring driver for UCD90xxx Sequencer and System Health
 * Controller series
 *
 * Copyright (C) 2011 Ericsson AB.
 */

#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/hex.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/pmbus.h>
#include <linux/gpio/driver.h>
#include <linux/timekeeping.h>
#include "pmbus.h"

enum chips { ucd9000, ucd90120, ucd90124, ucd90160, ucd90320, ucd9090,
             ucd90910 };

#define UCD9000_MONITOR_CONFIG          0xd5
#define UCD9000_NUM_PAGES               0xd6
#define UCD9000_FAN_CONFIG_INDEX        0xe7
#define UCD9000_FAN_CONFIG              0xe8
#define UCD9000_MFR_STATUS              0xf3
#define UCD9000_GPIO_SELECT             0xfa
#define UCD9000_GPIO_CONFIG             0xfb
#define UCD9000_DEVICE_ID               0xfd

/* GPIO CONFIG bits */
#define UCD9000_GPIO_CONFIG_ENABLE      BIT(0)
#define UCD9000_GPIO_CONFIG_OUT_ENABLE  BIT(1)
#define UCD9000_GPIO_CONFIG_OUT_VALUE   BIT(2)
#define UCD9000_GPIO_CONFIG_STATUS      BIT(3)
#define UCD9000_GPIO_INPUT              0
#define UCD9000_GPIO_OUTPUT             1

#define UCD9000_MON_TYPE(x)     (((x) >> 5) & 0x07)
#define UCD9000_MON_PAGE(x)     ((x) & 0x1f)

#define UCD9000_MON_VOLTAGE     1
#define UCD9000_MON_TEMPERATURE 2
#define UCD9000_MON_CURRENT     3
#define UCD9000_MON_VOLTAGE_HW  4

#define UCD9000_NUM_FAN         4

#define UCD9000_GPIO_NAME_LEN   16
#define UCD9090_NUM_GPIOS       23
#define UCD901XX_NUM_GPIOS      26
#define UCD90320_NUM_GPIOS      84
#define UCD90910_NUM_GPIOS      26

#define UCD9000_DEBUGFS_NAME_LEN        24
#define UCD9000_GPI_COUNT               8
#define UCD90320_GPI_COUNT              32

struct ucd9000_data {
        u8 fan_data[UCD9000_NUM_FAN][I2C_SMBUS_BLOCK_MAX];
        struct pmbus_driver_info info;
#ifdef CONFIG_GPIOLIB
        struct gpio_chip gpio;
#endif
        struct dentry *debugfs;
};
#define to_ucd9000_data(_info) container_of(_info, struct ucd9000_data, info)

struct ucd9000_debugfs_entry {
        struct i2c_client *client;
        u8 index;
};

/*
 * It has been observed that the UCD90320 randomly fails register access when
 * doing another access right on the back of a register write. To mitigate this
 * make sure that there is a minimum delay between a write access and the
 * following access. The 500 is based on experimental data. At a delay of
 * 350us the issue seems to go away. Add a bit of extra margin to allow for
 * system to system differences.
 */
#define UCD90320_WAIT_DELAY_US 500

static int ucd9000_get_fan_config(struct i2c_client *client, int fan)
{
        int fan_config = 0;
        struct ucd9000_data *data
          = to_ucd9000_data(pmbus_get_driver_info(client));

        if (data->fan_data[fan][3] & 1)
                fan_config |= PB_FAN_2_INSTALLED;   /* Use lower bit position */

        /* Pulses/revolution */
        fan_config |= (data->fan_data[fan][3] & 0x06) >> 1;

        return fan_config;
}

static int ucd9000_read_byte_data(struct i2c_client *client, int page, int reg)
{
        int ret = 0;
        int fan_config;

        switch (reg) {
        case PMBUS_FAN_CONFIG_12:
                if (page > 0)
                        return -ENXIO;

                ret = ucd9000_get_fan_config(client, 0);
                if (ret < 0)
                        return ret;
                fan_config = ret << 4;
                ret = ucd9000_get_fan_config(client, 1);
                if (ret < 0)
                        return ret;
                fan_config |= ret;
                ret = fan_config;
                break;
        case PMBUS_FAN_CONFIG_34:
                if (page > 0)
                        return -ENXIO;

                ret = ucd9000_get_fan_config(client, 2);
                if (ret < 0)
                        return ret;
                fan_config = ret << 4;
                ret = ucd9000_get_fan_config(client, 3);
                if (ret < 0)
                        return ret;
                fan_config |= ret;
                ret = fan_config;
                break;
        default:
                ret = -ENODATA;
                break;
        }
        return ret;
}

static const struct i2c_device_id ucd9000_id[] = {
        {"ucd9000", ucd9000},
        {"ucd90120", ucd90120},
        {"ucd90124", ucd90124},
        {"ucd90160", ucd90160},
        {"ucd90320", ucd90320},
        {"ucd9090", ucd9090},
        {"ucd90910", ucd90910},
        {}
};
MODULE_DEVICE_TABLE(i2c, ucd9000_id);

static const struct of_device_id __maybe_unused ucd9000_of_match[] = {
        {
                .compatible = "ti,ucd9000",
                .data = (void *)ucd9000
        },
        {
                .compatible = "ti,ucd90120",
                .data = (void *)ucd90120
        },
        {
                .compatible = "ti,ucd90124",
                .data = (void *)ucd90124
        },
        {
                .compatible = "ti,ucd90160",
                .data = (void *)ucd90160
        },
        {
                .compatible = "ti,ucd90320",
                .data = (void *)ucd90320
        },
        {
                .compatible = "ti,ucd9090",
                .data = (void *)ucd9090
        },
        {
                .compatible = "ti,ucd90910",
                .data = (void *)ucd90910
        },
        { },
};
MODULE_DEVICE_TABLE(of, ucd9000_of_match);

#ifdef CONFIG_GPIOLIB
static int ucd9000_gpio_read_config(struct i2c_client *client,
                                    unsigned int offset)
{
        int ret;

        /* No page set required */
        ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_SELECT, offset);
        if (ret < 0)
                return ret;

        return i2c_smbus_read_byte_data(client, UCD9000_GPIO_CONFIG);
}

static int ucd9000_gpio_get(struct gpio_chip *gc, unsigned int offset)
{
        struct i2c_client *client  = gpiochip_get_data(gc);
        int ret;

        ret = ucd9000_gpio_read_config(client, offset);
        if (ret < 0)
                return ret;

        return !!(ret & UCD9000_GPIO_CONFIG_STATUS);
}

static int ucd9000_gpio_set(struct gpio_chip *gc, unsigned int offset,
                            int value)
{
        struct i2c_client *client = gpiochip_get_data(gc);
        int ret;

        ret = ucd9000_gpio_read_config(client, offset);
        if (ret < 0) {
                dev_dbg(&client->dev, "failed to read GPIO %d config: %d\n",
                        offset, ret);
                return ret;
        }

        if (value) {
                if (ret & UCD9000_GPIO_CONFIG_OUT_VALUE)
                        return 0;

                ret |= UCD9000_GPIO_CONFIG_OUT_VALUE;
        } else {
                if (!(ret & UCD9000_GPIO_CONFIG_OUT_VALUE))
                        return 0;

                ret &= ~UCD9000_GPIO_CONFIG_OUT_VALUE;
        }

        ret |= UCD9000_GPIO_CONFIG_ENABLE;

        /* Page set not required */
        ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, ret);
        if (ret < 0) {
                dev_dbg(&client->dev, "Failed to write GPIO %d config: %d\n",
                        offset, ret);
                return ret;
        }

        ret &= ~UCD9000_GPIO_CONFIG_ENABLE;

        ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, ret);
        if (ret < 0)
                dev_dbg(&client->dev, "Failed to write GPIO %d config: %d\n",
                        offset, ret);

        return ret;
}

static int ucd9000_gpio_get_direction(struct gpio_chip *gc,
                                      unsigned int offset)
{
        struct i2c_client *client = gpiochip_get_data(gc);
        int ret;

        ret = ucd9000_gpio_read_config(client, offset);
        if (ret < 0)
                return ret;

        return !(ret & UCD9000_GPIO_CONFIG_OUT_ENABLE);
}

static int ucd9000_gpio_set_direction(struct gpio_chip *gc,
                                      unsigned int offset, bool direction_out,
                                      int requested_out)
{
        struct i2c_client *client = gpiochip_get_data(gc);
        int ret, config, out_val;

        ret = ucd9000_gpio_read_config(client, offset);
        if (ret < 0)
                return ret;

        if (direction_out) {
                out_val = requested_out ? UCD9000_GPIO_CONFIG_OUT_VALUE : 0;

                if (ret & UCD9000_GPIO_CONFIG_OUT_ENABLE) {
                        if ((ret & UCD9000_GPIO_CONFIG_OUT_VALUE) == out_val)
                                return 0;
                } else {
                        ret |= UCD9000_GPIO_CONFIG_OUT_ENABLE;
                }

                if (out_val)
                        ret |= UCD9000_GPIO_CONFIG_OUT_VALUE;
                else
                        ret &= ~UCD9000_GPIO_CONFIG_OUT_VALUE;

        } else {
                if (!(ret & UCD9000_GPIO_CONFIG_OUT_ENABLE))
                        return 0;

                ret &= ~UCD9000_GPIO_CONFIG_OUT_ENABLE;
        }

        ret |= UCD9000_GPIO_CONFIG_ENABLE;
        config = ret;

        /* Page set not required */
        ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, config);
        if (ret < 0)
                return ret;

        config &= ~UCD9000_GPIO_CONFIG_ENABLE;

        return i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, config);
}

static int ucd9000_gpio_direction_input(struct gpio_chip *gc,
                                        unsigned int offset)
{
        return ucd9000_gpio_set_direction(gc, offset, UCD9000_GPIO_INPUT, 0);
}

static int ucd9000_gpio_direction_output(struct gpio_chip *gc,
                                         unsigned int offset, int val)
{
        return ucd9000_gpio_set_direction(gc, offset, UCD9000_GPIO_OUTPUT,
                                          val);
}

static void ucd9000_probe_gpio(struct i2c_client *client,
                               const struct i2c_device_id *mid,
                               struct ucd9000_data *data)
{
        int rc;

        switch (mid->driver_data) {
        case ucd9090:
                data->gpio.ngpio = UCD9090_NUM_GPIOS;
                break;
        case ucd90120:
        case ucd90124:
        case ucd90160:
                data->gpio.ngpio = UCD901XX_NUM_GPIOS;
                break;
        case ucd90320:
                data->gpio.ngpio = UCD90320_NUM_GPIOS;
                break;
        case ucd90910:
                data->gpio.ngpio = UCD90910_NUM_GPIOS;
                break;
        default:
                return; /* GPIO support is optional. */
        }

        /*
         * Pinmux support has not been added to the new gpio_chip.
         * This support should be added when possible given the mux
         * behavior of these IO devices.
         */
        data->gpio.label = client->name;
        data->gpio.get_direction = ucd9000_gpio_get_direction;
        data->gpio.direction_input = ucd9000_gpio_direction_input;
        data->gpio.direction_output = ucd9000_gpio_direction_output;
        data->gpio.get = ucd9000_gpio_get;
        data->gpio.set = ucd9000_gpio_set;
        data->gpio.can_sleep = true;
        data->gpio.base = -1;
        data->gpio.parent = &client->dev;

        rc = devm_gpiochip_add_data(&client->dev, &data->gpio, client);
        if (rc)
                dev_warn(&client->dev, "Could not add gpiochip: %d\n", rc);
}
#else
static void ucd9000_probe_gpio(struct i2c_client *client,
                               const struct i2c_device_id *mid,
                               struct ucd9000_data *data)
{
}
#endif /* CONFIG_GPIOLIB */

#ifdef CONFIG_DEBUG_FS
static int ucd9000_get_mfr_status(struct i2c_client *client, u8 *buffer)
{
        int ret = pmbus_set_page(client, 0, 0xff);

        if (ret < 0)
                return ret;

        return i2c_smbus_read_block_data(client, UCD9000_MFR_STATUS, buffer);
}

static int ucd9000_debugfs_show_mfr_status_bit(void *data, u64 *val)
{
        struct ucd9000_debugfs_entry *entry = data;
        struct i2c_client *client = entry->client;
        u8 buffer[I2C_SMBUS_BLOCK_MAX];
        int ret, i;

        ret = ucd9000_get_mfr_status(client, buffer);
        if (ret < 0)
                return ret;

        /*
         * GPI fault bits are in sets of 8, two bytes from end of response.
         */
        i = ret - 3 - entry->index / 8;
        if (i >= 0)
                *val = !!(buffer[i] & BIT(entry->index % 8));

        return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_bit,
                         ucd9000_debugfs_show_mfr_status_bit, NULL, "%1lld\n");

static ssize_t ucd9000_debugfs_read_mfr_status(struct file *file,
                                               char __user *buf, size_t count,
                                               loff_t *ppos)
{
        struct i2c_client *client = file->private_data;
        u8 buffer[I2C_SMBUS_BLOCK_MAX];
        char str[(I2C_SMBUS_BLOCK_MAX * 2) + 2];
        char *res;
        int rc;

        rc = ucd9000_get_mfr_status(client, buffer);
        if (rc < 0)
                return rc;

        res = bin2hex(str, buffer, min(rc, I2C_SMBUS_BLOCK_MAX));
        *res++ = '\n';
        *res = 0;

        return simple_read_from_buffer(buf, count, ppos, str, res - str);
}

static const struct file_operations ucd9000_debugfs_show_mfr_status_fops = {
        .llseek = noop_llseek,
        .read = ucd9000_debugfs_read_mfr_status,
        .open = simple_open,
};

static int ucd9000_init_debugfs(struct i2c_client *client,
                                const struct i2c_device_id *mid,
                                struct ucd9000_data *data)
{
        struct dentry *debugfs;
        struct ucd9000_debugfs_entry *entries;
        int i, gpi_count;
        char name[UCD9000_DEBUGFS_NAME_LEN];

        debugfs = pmbus_get_debugfs_dir(client);
        if (!debugfs)
                return -ENOENT;

        data->debugfs = debugfs_create_dir(client->name, debugfs);

        /*
         * Of the chips this driver supports, only the UCD9090, UCD90160,
         * UCD90320, and UCD90910 report GPI faults in their MFR_STATUS
         * register, so only create the GPI fault debugfs attributes for those
         * chips.
         */
        if (mid->driver_data == ucd9090 || mid->driver_data == ucd90160 ||
            mid->driver_data == ucd90320 || mid->driver_data == ucd90910) {
                gpi_count = mid->driver_data == ucd90320 ? UCD90320_GPI_COUNT
                                                         : UCD9000_GPI_COUNT;
                entries = devm_kcalloc(&client->dev,
                                       gpi_count, sizeof(*entries),
                                       GFP_KERNEL);
                if (!entries)
                        return -ENOMEM;

                for (i = 0; i < gpi_count; i++) {
                        entries[i].client = client;
                        entries[i].index = i;
                        scnprintf(name, UCD9000_DEBUGFS_NAME_LEN,
                                  "gpi%d_alarm", i + 1);
                        debugfs_create_file(name, 0444, data->debugfs,
                                            &entries[i],
                                            &ucd9000_debugfs_mfr_status_bit);
                }
        }

        scnprintf(name, UCD9000_DEBUGFS_NAME_LEN, "mfr_status");
        debugfs_create_file(name, 0444, data->debugfs, client,
                            &ucd9000_debugfs_show_mfr_status_fops);

        return 0;
}
#else
static int ucd9000_init_debugfs(struct i2c_client *client,
                                const struct i2c_device_id *mid,
                                struct ucd9000_data *data)
{
        return 0;
}
#endif /* CONFIG_DEBUG_FS */

static int ucd9000_probe(struct i2c_client *client)
{
        u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
        struct ucd9000_data *data;
        struct pmbus_driver_info *info;
        const struct i2c_device_id *mid;
        enum chips chip;
        int i, ret;

        if (!i2c_check_functionality(client->adapter,
                                     I2C_FUNC_SMBUS_BYTE_DATA |
                                     I2C_FUNC_SMBUS_BLOCK_DATA))
                return -ENODEV;

        ret = i2c_smbus_read_block_data(client, UCD9000_DEVICE_ID,
                                        block_buffer);
        if (ret < 0) {
                dev_err(&client->dev, "Failed to read device ID\n");
                return ret;
        }
        block_buffer[ret] = '\0';
        dev_info(&client->dev, "Device ID %s\n", block_buffer);

        for (mid = ucd9000_id; mid->name[0]; mid++) {
                if (!strncasecmp(mid->name, block_buffer, strlen(mid->name)))
                        break;
        }
        if (!mid->name[0]) {
                dev_err(&client->dev, "Unsupported device\n");
                return -ENODEV;
        }

        if (client->dev.of_node)
                chip = (uintptr_t)of_device_get_match_data(&client->dev);
        else
                chip = mid->driver_data;

        if (chip != ucd9000 && strcmp(client->name, mid->name) != 0)
                dev_notice(&client->dev,
                           "Device mismatch: Configured %s, detected %s\n",
                           client->name, mid->name);

        data = devm_kzalloc(&client->dev, sizeof(struct ucd9000_data),
                            GFP_KERNEL);
        if (!data)
                return -ENOMEM;
        info = &data->info;

        ret = i2c_smbus_read_byte_data(client, UCD9000_NUM_PAGES);
        if (ret < 0) {
                dev_err(&client->dev,
                        "Failed to read number of active pages\n");
                return ret;
        }
        info->pages = ret;
        if (!info->pages) {
                dev_err(&client->dev, "No pages configured\n");
                return -ENODEV;
        }

        /* The internal temperature sensor is always active */
        info->func[0] = PMBUS_HAVE_TEMP;

        /* Everything else is configurable */
        ret = i2c_smbus_read_block_data(client, UCD9000_MONITOR_CONFIG,
                                        block_buffer);
        if (ret <= 0) {
                dev_err(&client->dev, "Failed to read configuration data\n");
                return -ENODEV;
        }
        for (i = 0; i < ret; i++) {
                int page = UCD9000_MON_PAGE(block_buffer[i]);

                if (page >= info->pages)
                        continue;

                switch (UCD9000_MON_TYPE(block_buffer[i])) {
                case UCD9000_MON_VOLTAGE:
                case UCD9000_MON_VOLTAGE_HW:
                        info->func[page] |= PMBUS_HAVE_VOUT
                          | PMBUS_HAVE_STATUS_VOUT;
                        break;
                case UCD9000_MON_TEMPERATURE:
                        info->func[page] |= PMBUS_HAVE_TEMP2
                          | PMBUS_HAVE_STATUS_TEMP;
                        break;
                case UCD9000_MON_CURRENT:
                        info->func[page] |= PMBUS_HAVE_IOUT
                          | PMBUS_HAVE_STATUS_IOUT;
                        break;
                default:
                        break;
                }
        }

        /* Fan configuration */
        if (mid->driver_data == ucd90124) {
                for (i = 0; i < UCD9000_NUM_FAN; i++) {
                        i2c_smbus_write_byte_data(client,
                                                  UCD9000_FAN_CONFIG_INDEX, i);
                        ret = i2c_smbus_read_block_data(client,
                                                        UCD9000_FAN_CONFIG,
                                                        data->fan_data[i]);
                        if (ret < 0)
                                return ret;
                }
                i2c_smbus_write_byte_data(client, UCD9000_FAN_CONFIG_INDEX, 0);

                info->read_byte_data = ucd9000_read_byte_data;
                info->func[0] |= PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12
                  | PMBUS_HAVE_FAN34 | PMBUS_HAVE_STATUS_FAN34;
        } else if (mid->driver_data == ucd90320) {
                /* Delay SMBus operations after a write */
                info->write_delay = UCD90320_WAIT_DELAY_US;
        }

        ucd9000_probe_gpio(client, mid, data);

        ret = pmbus_do_probe(client, info);
        if (ret)
                return ret;

        ret = ucd9000_init_debugfs(client, mid, data);
        if (ret)
                dev_warn(&client->dev, "Failed to register debugfs: %d\n",
                         ret);

        return 0;
}

/* This is the driver that will be inserted */
static struct i2c_driver ucd9000_driver = {
        .driver = {
                .name = "ucd9000",
                .of_match_table = of_match_ptr(ucd9000_of_match),
        },
        .probe = ucd9000_probe,
        .id_table = ucd9000_id,
};

module_i2c_driver(ucd9000_driver);

MODULE_AUTHOR("Guenter Roeck");
MODULE_DESCRIPTION("PMBus driver for TI UCD90xxx");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("PMBUS");