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atxp1.c

/*
    atxp1.c - kernel module for setting CPU VID and general purpose
                     I/Os using the Attansic ATXP1 chip.

    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; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-vid.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("System voltages control via Attansic ATXP1");
MODULE_VERSION("0.6.2");
MODULE_AUTHOR("Sebastian Witt <se.witt@gmx.net>");

#define ATXP1_VID 0x00
#define ATXP1_CVID      0x01
#define ATXP1_GPIO1     0x06
#define ATXP1_GPIO2     0x0a
#define ATXP1_VIDENA    0x20
#define ATXP1_VIDMASK   0x1f
#define ATXP1_GPIO1MASK 0x0f

static unsigned short normal_i2c[] = { 0x37, 0x4e, I2C_CLIENT_END };

I2C_CLIENT_INSMOD_1(atxp1);

static int atxp1_attach_adapter(struct i2c_adapter * adapter);
static int atxp1_detach_client(struct i2c_client * client);
static struct atxp1_data * atxp1_update_device(struct device *dev);
static int atxp1_detect(struct i2c_adapter *adapter, int address, int kind);

static struct i2c_driver atxp1_driver = {
      .driver = {
            .name = "atxp1",
      },
      .attach_adapter = atxp1_attach_adapter,
      .detach_client    = atxp1_detach_client,
};

struct atxp1_data {
      struct i2c_client client;
      struct device *hwmon_dev;
      struct mutex update_lock;
      unsigned long last_updated;
      u8 valid;
      struct {
            u8 vid;           /* VID output register */
            u8 cpu_vid; /* VID input from CPU */
            u8 gpio1;   /* General purpose I/O register 1 */
            u8 gpio2;   /* General purpose I/O register 2 */
      } reg;
      u8 vrm;                 /* Detected CPU VRM */
};

static struct atxp1_data * atxp1_update_device(struct device *dev)
{
      struct i2c_client *client;
      struct atxp1_data *data;

      client = to_i2c_client(dev);
      data = i2c_get_clientdata(client);

      mutex_lock(&data->update_lock);

      if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {

            /* Update local register data */
            data->reg.vid = i2c_smbus_read_byte_data(client, ATXP1_VID);
            data->reg.cpu_vid = i2c_smbus_read_byte_data(client, ATXP1_CVID);
            data->reg.gpio1 = i2c_smbus_read_byte_data(client, ATXP1_GPIO1);
            data->reg.gpio2 = i2c_smbus_read_byte_data(client, ATXP1_GPIO2);

            data->valid = 1;
      }

      mutex_unlock(&data->update_lock);

      return(data);
}

/* sys file functions for cpu0_vid */
static ssize_t atxp1_showvcore(struct device *dev, struct device_attribute *attr, char *buf)
{
      int size;
      struct atxp1_data *data;

      data = atxp1_update_device(dev);

      size = sprintf(buf, "%d\n", vid_from_reg(data->reg.vid & ATXP1_VIDMASK, data->vrm));

      return size;
}

static ssize_t atxp1_storevcore(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
      struct atxp1_data *data;
      struct i2c_client *client;
      int vid, cvid;
      unsigned int vcore;

      client = to_i2c_client(dev);
      data = atxp1_update_device(dev);

      vcore = simple_strtoul(buf, NULL, 10);
      vcore /= 25;
      vcore *= 25;

      /* Calculate VID */
      vid = vid_to_reg(vcore, data->vrm);

      if (vid < 0) {
            dev_err(dev, "VID calculation failed.\n");
            return -1;
      }

      /* If output enabled, use control register value. Otherwise original CPU VID */
      if (data->reg.vid & ATXP1_VIDENA)
            cvid = data->reg.vid & ATXP1_VIDMASK;
      else
            cvid = data->reg.cpu_vid;

      /* Nothing changed, aborting */
      if (vid == cvid)
            return count;

      dev_dbg(dev, "Setting VCore to %d mV (0x%02x)\n", vcore, vid);

      /* Write every 25 mV step to increase stability */
      if (cvid > vid) {
            for (; cvid >= vid; cvid--) {
                  i2c_smbus_write_byte_data(client, ATXP1_VID, cvid | ATXP1_VIDENA);
            }
      }
      else {
            for (; cvid <= vid; cvid++) {
                  i2c_smbus_write_byte_data(client, ATXP1_VID, cvid | ATXP1_VIDENA);
            }
      }

      data->valid = 0;

      return count;
}

/* CPU core reference voltage
    unit: millivolt
*/
static DEVICE_ATTR(cpu0_vid, S_IRUGO | S_IWUSR, atxp1_showvcore, atxp1_storevcore);

/* sys file functions for GPIO1 */
static ssize_t atxp1_showgpio1(struct device *dev, struct device_attribute *attr, char *buf)
{
      int size;
      struct atxp1_data *data;

      data = atxp1_update_device(dev);

      size = sprintf(buf, "0x%02x\n", data->reg.gpio1 & ATXP1_GPIO1MASK);

      return size;
}

static ssize_t atxp1_storegpio1(struct device *dev, struct device_attribute *attr, const char*buf, size_t count)
{
      struct atxp1_data *data;
      struct i2c_client *client;
      unsigned int value;

      client = to_i2c_client(dev);
      data = atxp1_update_device(dev);

      value = simple_strtoul(buf, NULL, 16);

      value &= ATXP1_GPIO1MASK;

      if (value != (data->reg.gpio1 & ATXP1_GPIO1MASK)) {
            dev_info(dev, "Writing 0x%x to GPIO1.\n", value);

            i2c_smbus_write_byte_data(client, ATXP1_GPIO1, value);

            data->valid = 0;
      }

      return count;
}

/* GPIO1 data register
    unit: Four bit as hex (e.g. 0x0f)
*/
static DEVICE_ATTR(gpio1, S_IRUGO | S_IWUSR, atxp1_showgpio1, atxp1_storegpio1);

/* sys file functions for GPIO2 */
static ssize_t atxp1_showgpio2(struct device *dev, struct device_attribute *attr, char *buf)
{
      int size;
      struct atxp1_data *data;

      data = atxp1_update_device(dev);

      size = sprintf(buf, "0x%02x\n", data->reg.gpio2);

      return size;
}

static ssize_t atxp1_storegpio2(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
      struct atxp1_data *data;
      struct i2c_client *client;
      unsigned int value;

      client = to_i2c_client(dev);
      data = atxp1_update_device(dev);

      value = simple_strtoul(buf, NULL, 16) & 0xff;

      if (value != data->reg.gpio2) {
            dev_info(dev, "Writing 0x%x to GPIO1.\n", value);

            i2c_smbus_write_byte_data(client, ATXP1_GPIO2, value);

            data->valid = 0;
      }

      return count;
}

/* GPIO2 data register
    unit: Eight bit as hex (e.g. 0xff)
*/
static DEVICE_ATTR(gpio2, S_IRUGO | S_IWUSR, atxp1_showgpio2, atxp1_storegpio2);

static struct attribute *atxp1_attributes[] = {
      &dev_attr_gpio1.attr,
      &dev_attr_gpio2.attr,
      &dev_attr_cpu0_vid.attr,
      NULL
};

static const struct attribute_group atxp1_group = {
      .attrs = atxp1_attributes,
};


static int atxp1_attach_adapter(struct i2c_adapter *adapter)
{
      if (!(adapter->class & I2C_CLASS_HWMON))
            return 0;
      return i2c_probe(adapter, &addr_data, &atxp1_detect);
};

static int atxp1_detect(struct i2c_adapter *adapter, int address, int kind)
{
      struct i2c_client * new_client;
      struct atxp1_data * data;
      int err = 0;
      u8 temp;

      if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
            goto exit;

      if (!(data = kzalloc(sizeof(struct atxp1_data), GFP_KERNEL))) {
            err = -ENOMEM;
            goto exit;
      }

      new_client = &data->client;
      i2c_set_clientdata(new_client, data);

      new_client->addr = address;
      new_client->adapter = adapter;
      new_client->driver = &atxp1_driver;
      new_client->flags = 0;

      /* Detect ATXP1, checking if vendor ID registers are all zero */
      if (!((i2c_smbus_read_byte_data(new_client, 0x3e) == 0) &&
           (i2c_smbus_read_byte_data(new_client, 0x3f) == 0) &&
           (i2c_smbus_read_byte_data(new_client, 0xfe) == 0) &&
           (i2c_smbus_read_byte_data(new_client, 0xff) == 0) )) {

            /* No vendor ID, now checking if registers 0x10,0x11 (non-existent)
             * showing the same as register 0x00 */
            temp = i2c_smbus_read_byte_data(new_client, 0x00);

            if (!((i2c_smbus_read_byte_data(new_client, 0x10) == temp) &&
                   (i2c_smbus_read_byte_data(new_client, 0x11) == temp) ))
                  goto exit_free;
      }

      /* Get VRM */
      data->vrm = vid_which_vrm();

      if ((data->vrm != 90) && (data->vrm != 91)) {
            dev_err(&new_client->dev, "Not supporting VRM %d.%d\n",
                        data->vrm / 10, data->vrm % 10);
            goto exit_free;
      }

      strncpy(new_client->name, "atxp1", I2C_NAME_SIZE);

      data->valid = 0;

      mutex_init(&data->update_lock);

      err = i2c_attach_client(new_client);

      if (err)
      {
            dev_err(&new_client->dev, "Attach client error.\n");
            goto exit_free;
      }

      /* Register sysfs hooks */
      if ((err = sysfs_create_group(&new_client->dev.kobj, &atxp1_group)))
            goto exit_detach;

      data->hwmon_dev = hwmon_device_register(&new_client->dev);
      if (IS_ERR(data->hwmon_dev)) {
            err = PTR_ERR(data->hwmon_dev);
            goto exit_remove_files;
      }

      dev_info(&new_client->dev, "Using VRM: %d.%d\n",
                   data->vrm / 10, data->vrm % 10);

      return 0;

exit_remove_files:
      sysfs_remove_group(&new_client->dev.kobj, &atxp1_group);
exit_detach:
      i2c_detach_client(new_client);
exit_free:
      kfree(data);
exit:
      return err;
};

static int atxp1_detach_client(struct i2c_client * client)
{
      struct atxp1_data * data = i2c_get_clientdata(client);
      int err;

      hwmon_device_unregister(data->hwmon_dev);
      sysfs_remove_group(&client->dev.kobj, &atxp1_group);

      err = i2c_detach_client(client);

      if (err)
            dev_err(&client->dev, "Failed to detach client.\n");
      else
            kfree(data);

      return err;
};

static int __init atxp1_init(void)
{
      return i2c_add_driver(&atxp1_driver);
};

static void __exit atxp1_exit(void)
{
      i2c_del_driver(&atxp1_driver);
};

module_init(atxp1_init);
module_exit(atxp1_exit);

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