/*
   * tef6862.c Philips TEF6862 Car Radio Enhanced Selectivity Tuner
   * Copyright (c) 2009 Intel Corporation
   *
   * 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.
   *
   * 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/module.h>
  #include <linux/init.h>
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/interrupt.h>
  #include <linux/i2c.h>
  #include <linux/slab.h>
  #include <media/v4l2-ioctl.h>
  #include <media/v4l2-device.h>
  
  #define DRIVER_NAME "tef6862"
  
  #define FREQ_MUL 16000
  
  #define TEF6862_LO_FREQ (875U * FREQ_MUL / 10)
  #define TEF6862_HI_FREQ (108U * FREQ_MUL)
  
  /* Write mode sub addresses */
  #define WM_SUB_BANDWIDTH	0x0
  #define WM_SUB_PLLM		0x1
  #define WM_SUB_PLLL		0x2
  #define WM_SUB_DAA		0x3
  #define WM_SUB_AGC		0x4
  #define WM_SUB_BAND		0x5
  #define WM_SUB_CONTROL		0x6
  #define WM_SUB_LEVEL		0x7
  #define WM_SUB_IFCF		0x8
  #define WM_SUB_IFCAP		0x9
  #define WM_SUB_ACD		0xA
  #define WM_SUB_TEST		0xF
  
  /* Different modes of the MSA register */
  #define MSA_MODE_BUFFER		0x0
  #define MSA_MODE_PRESET		0x1
  #define MSA_MODE_SEARCH		0x2
  #define MSA_MODE_AF_UPDATE	0x3
  #define MSA_MODE_JUMP		0x4
  #define MSA_MODE_CHECK		0x5
  #define MSA_MODE_LOAD		0x6
  #define MSA_MODE_END		0x7
  #define MSA_MODE_SHIFT		5
  
  struct tef6862_state {
  	struct v4l2_subdev sd;
  	unsigned long freq;
  };
  
  static inline struct tef6862_state *to_state(struct v4l2_subdev *sd)
  {
  	return container_of(sd, struct tef6862_state, sd);
  }
  
  static u16 tef6862_sigstr(struct i2c_client *client)
  {
  	u8 buf[4];
  	int err = i2c_master_recv(client, buf, sizeof(buf));
  	if (err == sizeof(buf))
  		return buf[3] << 8;
  	return 0;
  }
  
  static int tef6862_g_tuner(struct v4l2_subdev *sd, struct v4l2_tuner *v)
  {
  	if (v->index > 0)
  		return -EINVAL;
  
  	/* only support FM for now */
  	strlcpy(v->name, "FM", sizeof(v->name));
  	v->type = V4L2_TUNER_RADIO;
  	v->rangelow = TEF6862_LO_FREQ;
  	v->rangehigh = TEF6862_HI_FREQ;
  	v->rxsubchans = V4L2_TUNER_SUB_MONO;
  	v->capability = V4L2_TUNER_CAP_LOW;
  	v->audmode = V4L2_TUNER_MODE_STEREO;
  	v->signal = tef6862_sigstr(v4l2_get_subdevdata(sd));
  
  	return 0;
  }
  
  static int tef6862_s_tuner(struct v4l2_subdev *sd, const struct v4l2_tuner *v)
  {
  	return v->index ? -EINVAL : 0;
  }
  
  static int tef6862_s_frequency(struct v4l2_subdev *sd, const struct v4l2_frequency *f)
  {
  	struct tef6862_state *state = to_state(sd);
  	struct i2c_client *client = v4l2_get_subdevdata(sd);
  	unsigned freq = f->frequency;
  	u16 pll;
  	u8 i2cmsg[3];
  	int err;
  
  	if (f->tuner != 0)
  		return -EINVAL;
  
  	freq = clamp(freq, TEF6862_LO_FREQ, TEF6862_HI_FREQ);
  	pll = 1964 + ((freq - TEF6862_LO_FREQ) * 20) / FREQ_MUL;
  	i2cmsg[0] = (MSA_MODE_PRESET << MSA_MODE_SHIFT) | WM_SUB_PLLM;
  	i2cmsg[1] = (pll >> 8) & 0xff;
  	i2cmsg[2] = pll & 0xff;
  
  	err = i2c_master_send(client, i2cmsg, sizeof(i2cmsg));
  	if (err != sizeof(i2cmsg))
  		return err < 0 ? err : -EIO;
  
  	state->freq = freq;
  	return 0;
  }
  
  static int tef6862_g_frequency(struct v4l2_subdev *sd, struct v4l2_frequency *f)
  {
  	struct tef6862_state *state = to_state(sd);
  
  	if (f->tuner != 0)
  		return -EINVAL;
  	f->type = V4L2_TUNER_RADIO;
  	f->frequency = state->freq;
  	return 0;
  }
  
  static const struct v4l2_subdev_tuner_ops tef6862_tuner_ops = {
  	.g_tuner = tef6862_g_tuner,
  	.s_tuner = tef6862_s_tuner,
  	.s_frequency = tef6862_s_frequency,
  	.g_frequency = tef6862_g_frequency,
  };
  
  static const struct v4l2_subdev_ops tef6862_ops = {
  	.tuner = &tef6862_tuner_ops,
  };
  
  /*
   * Generic i2c probe
   * concerning the addresses: i2c wants 7 bit (without the r/w bit), so '>>1'
   */
  
  static int tef6862_probe(struct i2c_client *client,
  			 const struct i2c_device_id *id)
  {
  	struct tef6862_state *state;
  	struct v4l2_subdev *sd;
  
  	/* Check if the adapter supports the needed features */
  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
  		return -EIO;
  
  	v4l_info(client, "chip found @ 0x%02x (%s)
  ",
  			client->addr << 1, client->adapter->name);
  
  	state = kzalloc(sizeof(struct tef6862_state), GFP_KERNEL);
  	if (state == NULL)
  		return -ENOMEM;
  	state->freq = TEF6862_LO_FREQ;
  
  	sd = &state->sd;
  	v4l2_i2c_subdev_init(sd, client, &tef6862_ops);
  
  	return 0;
  }
  
  static int tef6862_remove(struct i2c_client *client)
  {
  	struct v4l2_subdev *sd = i2c_get_clientdata(client);
  
  	v4l2_device_unregister_subdev(sd);
  	kfree(to_state(sd));
  	return 0;
  }
  
  static const struct i2c_device_id tef6862_id[] = {
  	{DRIVER_NAME, 0},
  	{},
  };
  
  MODULE_DEVICE_TABLE(i2c, tef6862_id);
  
  static struct i2c_driver tef6862_driver = {
  	.driver = {
  		.name	= DRIVER_NAME,
  	},
  	.probe		= tef6862_probe,
  	.remove		= tef6862_remove,
  	.id_table	= tef6862_id,
  };
  
  module_i2c_driver(tef6862_driver);
  
  MODULE_DESCRIPTION("TEF6862 Car Radio Enhanced Selectivity Tuner");
  MODULE_AUTHOR("Mocean Laboratories");
  MODULE_LICENSE("GPL v2");