drivers/media/video/cx18/cx18-av-audio.c - maze/linux - Git at Google

 /*
  *  cx18 ADEC audio functions
  *
  *  Derived from cx25840-audio.c
  *
  *  Copyright (C) 2007  Hans Verkuil <hverkuil@xs4all.nl>
  *  Copyright (C) 2008  Andy Walls <awalls@radix.net>
  *
  *  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., 51 Franklin Street, Fifth Floor, Boston, MA
  *  02110-1301, USA.
  */

 #include "cx18-driver.h"

 static int set_audclk_freq(struct cx18 *cx, u32 freq)
 {
 	struct cx18_av_state *state = &cx->av_state;

 	if (freq != 32000 && freq != 44100 && freq != 48000)
 		return -EINVAL;

 	/*
 	 * The PLL parameters are based on the external crystal frequency that
 	 * would ideally be:
 	 *
 	 * NTSC Color subcarrier freq * 8 =
 	 * 	4.5 MHz/286 * 455/2 * 8 = 28.63636363... MHz
 	 *
 	 * The accidents of history and rationale that explain from where this
 	 * combination of magic numbers originate can be found in:
 	 *
 	 * [1] Abrahams, I. C., "Choice of Chrominance Subcarrier Frequency in
 	 * the NTSC Standards", Proceedings of the I-R-E, January 1954, pp 79-80
 	 *
 	 * [2] Abrahams, I. C., "The 'Frequency Interleaving' Principle in the
 	 * NTSC Standards", Proceedings of the I-R-E, January 1954, pp 81-83
 	 *
 	 * As Mike Bradley has rightly pointed out, it's not the exact crystal
 	 * frequency that matters, only that all parts of the driver and
 	 * firmware are using the same value (close to the ideal value).
 	 *
 	 * Since I have a strong suspicion that, if the firmware ever assumes a
 	 * crystal value at all, it will assume 28.636360 MHz, the crystal
 	 * freq used in calculations in this driver will be:
 	 *
 	 *	xtal_freq = 28.636360 MHz
 	 *
 	 * an error of less than 0.13 ppm which is way, way better than any off
 	 * the shelf crystal will have for accuracy anyway.
 	 *
 	 * Below I aim to run the PLLs' VCOs near 400 MHz to minimze error.
 	 *
 	 * Many thanks to Jeff Campbell and Mike Bradley for their extensive
 	 * investigation, experimentation, testing, and suggested solutions of
 	 * of audio/video sync problems with SVideo and CVBS captures.
 	 */

 	if (state->aud_input > CX18_AV_AUDIO_SERIAL2) {
 		switch (freq) {
 		case 32000:
 			/*
 			 * VID_PLL Integer = 0x0f, VID_PLL Post Divider = 0x04
 			 * AUX_PLL Integer = 0x0d, AUX PLL Post Divider = 0x20
 			 */
 			cx18_av_write4(cx, 0x108, 0x200d040f);

 			/* VID_PLL Fraction = 0x2be2fe */
 			/* xtal * 0xf.15f17f0/4 = 108 MHz: 432 MHz pre-postdiv*/
 			cx18_av_write4(cx, 0x10c, 0x002be2fe);

 			/* AUX_PLL Fraction = 0x176740c */
 			/* xtal * 0xd.bb3a060/0x20 = 32000 * 384: 393 MHz p-pd*/
 			cx18_av_write4(cx, 0x110, 0x0176740c);

 			/* src3/4/6_ctl */
 			/* 0x1.f77f = (4 * xtal/8*2/455) / 32000 */
 			cx18_av_write4(cx, 0x900, 0x0801f77f);
 			cx18_av_write4(cx, 0x904, 0x0801f77f);
 			cx18_av_write4(cx, 0x90c, 0x0801f77f);

 			/* SA_MCLK_SEL=1, SA_MCLK_DIV=0x20 */
 			cx18_av_write(cx, 0x127, 0x60);

 			/* AUD_COUNT = 0x2fff = 8 samples * 4 * 384 - 1 */
 			cx18_av_write4(cx, 0x12c, 0x11202fff);

 			/*
 			 * EN_AV_LOCK = 0
 			 * VID_COUNT = 0x0d2ef8 = 107999.000 * 8 =
 			 *  ((8 samples/32,000) * (13,500,000 * 8) * 4 - 1) * 8
 			 */
 			cx18_av_write4(cx, 0x128, 0xa00d2ef8);
 			break;

 		case 44100:
 			/*
 			 * VID_PLL Integer = 0x0f, VID_PLL Post Divider = 0x04
 			 * AUX_PLL Integer = 0x0e, AUX PLL Post Divider = 0x18
 			 */
 			cx18_av_write4(cx, 0x108, 0x180e040f);

 			/* VID_PLL Fraction = 0x2be2fe */
 			/* xtal * 0xf.15f17f0/4 = 108 MHz: 432 MHz pre-postdiv*/
 			cx18_av_write4(cx, 0x10c, 0x002be2fe);

 			/* AUX_PLL Fraction = 0x062a1f2 */
 			/* xtal * 0xe.3150f90/0x18 = 44100 * 384: 406 MHz p-pd*/
 			cx18_av_write4(cx, 0x110, 0x0062a1f2);

 			/* src3/4/6_ctl */
 			/* 0x1.6d59 = (4 * xtal/8*2/455) / 44100 */
 			cx18_av_write4(cx, 0x900, 0x08016d59);
 			cx18_av_write4(cx, 0x904, 0x08016d59);
 			cx18_av_write4(cx, 0x90c, 0x08016d59);

 			/* SA_MCLK_SEL=1, SA_MCLK_DIV=0x18 */
 			cx18_av_write(cx, 0x127, 0x58);

 			/* AUD_COUNT = 0x92ff = 49 samples * 2 * 384 - 1 */
 			cx18_av_write4(cx, 0x12c, 0x112092ff);

 			/*
 			 * EN_AV_LOCK = 0
 			 * VID_COUNT = 0x1d4bf8 = 239999.000 * 8 =
 			 *  ((49 samples/44,100) * (13,500,000 * 8) * 2 - 1) * 8
 			 */
 			cx18_av_write4(cx, 0x128, 0xa01d4bf8);
 			break;

 		case 48000:
 			/*
 			 * VID_PLL Integer = 0x0f, VID_PLL Post Divider = 0x04
 			 * AUX_PLL Integer = 0x0e, AUX PLL Post Divider = 0x16
 			 */
 			cx18_av_write4(cx, 0x108, 0x160e040f);

 			/* VID_PLL Fraction = 0x2be2fe */
 			/* xtal * 0xf.15f17f0/4 = 108 MHz: 432 MHz pre-postdiv*/
 			cx18_av_write4(cx, 0x10c, 0x002be2fe);

 			/* AUX_PLL Fraction = 0x05227ad */
 			/* xtal * 0xe.2913d68/0x16 = 48000 * 384: 406 MHz p-pd*/
 			cx18_av_write4(cx, 0x110, 0x005227ad);

 			/* src3/4/6_ctl */
 			/* 0x1.4faa = (4 * xtal/8*2/455) / 48000 */
 			cx18_av_write4(cx, 0x900, 0x08014faa);
 			cx18_av_write4(cx, 0x904, 0x08014faa);
 			cx18_av_write4(cx, 0x90c, 0x08014faa);

 			/* SA_MCLK_SEL=1, SA_MCLK_DIV=0x16 */
 			cx18_av_write(cx, 0x127, 0x56);

 			/* AUD_COUNT = 0x5fff = 4 samples * 16 * 384 - 1 */
 			cx18_av_write4(cx, 0x12c, 0x11205fff);

 			/*
 			 * EN_AV_LOCK = 0
 			 * VID_COUNT = 0x1193f8 = 143999.000 * 8 =
 			 *  ((4 samples/48,000) * (13,500,000 * 8) * 16 - 1) * 8
 			 */
 			cx18_av_write4(cx, 0x128, 0xa01193f8);
 			break;
 		}
 	} else {
 		switch (freq) {
 		case 32000:
 			/*
 			 * VID_PLL Integer = 0x0f, VID_PLL Post Divider = 0x04
 			 * AUX_PLL Integer = 0x0d, AUX PLL Post Divider = 0x30
 			 */
 			cx18_av_write4(cx, 0x108, 0x300d040f);

 			/* VID_PLL Fraction = 0x2be2fe */
 			/* xtal * 0xf.15f17f0/4 = 108 MHz: 432 MHz pre-postdiv*/
 			cx18_av_write4(cx, 0x10c, 0x002be2fe);

 			/* AUX_PLL Fraction = 0x176740c */
 			/* xtal * 0xd.bb3a060/0x30 = 32000 * 256: 393 MHz p-pd*/
 			cx18_av_write4(cx, 0x110, 0x0176740c);

 			/* src1_ctl */
 			/* 0x1.0000 = 32000/32000 */
 			cx18_av_write4(cx, 0x8f8, 0x08010000);

 			/* src3/4/6_ctl */
 			/* 0x2.0000 = 2 * (32000/32000) */
 			cx18_av_write4(cx, 0x900, 0x08020000);
 			cx18_av_write4(cx, 0x904, 0x08020000);
 			cx18_av_write4(cx, 0x90c, 0x08020000);

 			/* SA_MCLK_SEL=1, SA_MCLK_DIV=0x30 */
 			cx18_av_write(cx, 0x127, 0x70);

 			/* AUD_COUNT = 0x1fff = 8 samples * 4 * 256 - 1 */
 			cx18_av_write4(cx, 0x12c, 0x11201fff);

 			/*
 			 * EN_AV_LOCK = 0
 			 * VID_COUNT = 0x0d2ef8 = 107999.000 * 8 =
 			 *  ((8 samples/32,000) * (13,500,000 * 8) * 4 - 1) * 8
 			 */
 			cx18_av_write4(cx, 0x128, 0xa00d2ef8);
 			break;

 		case 44100:
 			/*
 			 * VID_PLL Integer = 0x0f, VID_PLL Post Divider = 0x04
 			 * AUX_PLL Integer = 0x0e, AUX PLL Post Divider = 0x24
 			 */
 			cx18_av_write4(cx, 0x108, 0x240e040f);

 			/* VID_PLL Fraction = 0x2be2fe */
 			/* xtal * 0xf.15f17f0/4 = 108 MHz: 432 MHz pre-postdiv*/
 			cx18_av_write4(cx, 0x10c, 0x002be2fe);

 			/* AUX_PLL Fraction = 0x062a1f2 */
 			/* xtal * 0xe.3150f90/0x24 = 44100 * 256: 406 MHz p-pd*/
 			cx18_av_write4(cx, 0x110, 0x0062a1f2);

 			/* src1_ctl */
 			/* 0x1.60cd = 44100/32000 */
 			cx18_av_write4(cx, 0x8f8, 0x080160cd);

 			/* src3/4/6_ctl */
 			/* 0x1.7385 = 2 * (32000/44100) */
 			cx18_av_write4(cx, 0x900, 0x08017385);
 			cx18_av_write4(cx, 0x904, 0x08017385);
 			cx18_av_write4(cx, 0x90c, 0x08017385);

 			/* SA_MCLK_SEL=1, SA_MCLK_DIV=0x24 */
 			cx18_av_write(cx, 0x127, 0x64);

 			/* AUD_COUNT = 0x61ff = 49 samples * 2 * 256 - 1 */
 			cx18_av_write4(cx, 0x12c, 0x112061ff);

 			/*
 			 * EN_AV_LOCK = 0
 			 * VID_COUNT = 0x1d4bf8 = 239999.000 * 8 =
 			 *  ((49 samples/44,100) * (13,500,000 * 8) * 2 - 1) * 8
 			 */
 			cx18_av_write4(cx, 0x128, 0xa01d4bf8);
 			break;

 		case 48000:
 			/*
 			 * VID_PLL Integer = 0x0f, VID_PLL Post Divider = 0x04
 			 * AUX_PLL Integer = 0x0d, AUX PLL Post Divider = 0x20
 			 */
 			cx18_av_write4(cx, 0x108, 0x200d040f);

 			/* VID_PLL Fraction = 0x2be2fe */
 			/* xtal * 0xf.15f17f0/4 = 108 MHz: 432 MHz pre-postdiv*/
 			cx18_av_write4(cx, 0x10c, 0x002be2fe);

 			/* AUX_PLL Fraction = 0x176740c */
 			/* xtal * 0xd.bb3a060/0x20 = 48000 * 256: 393 MHz p-pd*/
 			cx18_av_write4(cx, 0x110, 0x0176740c);

 			/* src1_ctl */
 			/* 0x1.8000 = 48000/32000 */
 			cx18_av_write4(cx, 0x8f8, 0x08018000);

 			/* src3/4/6_ctl */
 			/* 0x1.5555 = 2 * (32000/48000) */
 			cx18_av_write4(cx, 0x900, 0x08015555);
 			cx18_av_write4(cx, 0x904, 0x08015555);
 			cx18_av_write4(cx, 0x90c, 0x08015555);

 			/* SA_MCLK_SEL=1, SA_MCLK_DIV=0x20 */
 			cx18_av_write(cx, 0x127, 0x60);

 			/* AUD_COUNT = 0x3fff = 4 samples * 16 * 256 - 1 */
 			cx18_av_write4(cx, 0x12c, 0x11203fff);

 			/*
 			 * EN_AV_LOCK = 0
 			 * VID_COUNT = 0x1193f8 = 143999.000 * 8 =
 			 *  ((4 samples/48,000) * (13,500,000 * 8) * 16 - 1) * 8
 			 */
 			cx18_av_write4(cx, 0x128, 0xa01193f8);
 			break;
 		}
 	}

 	state->audclk_freq = freq;

 	return 0;
 }

 void cx18_av_audio_set_path(struct cx18 *cx)
 {
 	struct cx18_av_state *state = &cx->av_state;
 	u8 v;

 	/* stop microcontroller */
 	v = cx18_av_read(cx, 0x803) & ~0x10;
 	cx18_av_write_expect(cx, 0x803, v, v, 0x1f);

 	/* assert soft reset */
 	v = cx18_av_read(cx, 0x810) | 0x01;
 	cx18_av_write_expect(cx, 0x810, v, v, 0x0f);

 	/* Mute everything to prevent the PFFT! */
 	cx18_av_write(cx, 0x8d3, 0x1f);

 	if (state->aud_input <= CX18_AV_AUDIO_SERIAL2) {
 		/* Set Path1 to Serial Audio Input */
 		cx18_av_write4(cx, 0x8d0, 0x01011012);

 		/* The microcontroller should not be started for the
 		 * non-tuner inputs: autodetection is specific for
 		 * TV audio. */
 	} else {
 		/* Set Path1 to Analog Demod Main Channel */
 		cx18_av_write4(cx, 0x8d0, 0x1f063870);
 	}

 	set_audclk_freq(cx, state->audclk_freq);

 	/* deassert soft reset */
 	v = cx18_av_read(cx, 0x810) & ~0x01;
 	cx18_av_write_expect(cx, 0x810, v, v, 0x0f);

 	if (state->aud_input > CX18_AV_AUDIO_SERIAL2) {
 		/* When the microcontroller detects the
 		 * audio format, it will unmute the lines */
 		v = cx18_av_read(cx, 0x803) | 0x10;
 		cx18_av_write_expect(cx, 0x803, v, v, 0x1f);
 	}
 }

 static int get_volume(struct cx18 *cx)
 {
 	/* Volume runs +18dB to -96dB in 1/2dB steps
 	 * change to fit the msp3400 -114dB to +12dB range */

 	/* check PATH1_VOLUME */
 	int vol = 228 - cx18_av_read(cx, 0x8d4);
 	vol = (vol / 2) + 23;
 	return vol << 9;
 }

 static void set_volume(struct cx18 *cx, int volume)
 {
 	/* First convert the volume to msp3400 values (0-127) */
 	int vol = volume >> 9;
 	/* now scale it up to cx18_av values
 	 * -114dB to -96dB maps to 0
 	 * this should be 19, but in my testing that was 4dB too loud */
 	if (vol <= 23)
 		vol = 0;
 	else
 		vol -= 23;

 	/* PATH1_VOLUME */
 	cx18_av_write(cx, 0x8d4, 228 - (vol * 2));
 }

 static int get_bass(struct cx18 *cx)
 {
 	/* bass is 49 steps +12dB to -12dB */

 	/* check PATH1_EQ_BASS_VOL */
 	int bass = cx18_av_read(cx, 0x8d9) & 0x3f;
 	bass = (((48 - bass) * 0xffff) + 47) / 48;
 	return bass;
 }

 static void set_bass(struct cx18 *cx, int bass)
 {
 	/* PATH1_EQ_BASS_VOL */
 	cx18_av_and_or(cx, 0x8d9, ~0x3f, 48 - (bass * 48 / 0xffff));
 }

 static int get_treble(struct cx18 *cx)
 {
 	/* treble is 49 steps +12dB to -12dB */

 	/* check PATH1_EQ_TREBLE_VOL */
 	int treble = cx18_av_read(cx, 0x8db) & 0x3f;
 	treble = (((48 - treble) * 0xffff) + 47) / 48;
 	return treble;
 }

 static void set_treble(struct cx18 *cx, int treble)
 {
 	/* PATH1_EQ_TREBLE_VOL */
 	cx18_av_and_or(cx, 0x8db, ~0x3f, 48 - (treble * 48 / 0xffff));
 }

 static int get_balance(struct cx18 *cx)
 {
 	/* balance is 7 bit, 0 to -96dB */

 	/* check PATH1_BAL_LEVEL */
 	int balance = cx18_av_read(cx, 0x8d5) & 0x7f;
 	/* check PATH1_BAL_LEFT */
 	if ((cx18_av_read(cx, 0x8d5) & 0x80) == 0)
 		balance = 0x80 - balance;
 	else
 		balance = 0x80 + balance;
 	return balance << 8;
 }

 static void set_balance(struct cx18 *cx, int balance)
 {
 	int bal = balance >> 8;
 	if (bal > 0x80) {
 		/* PATH1_BAL_LEFT */
 		cx18_av_and_or(cx, 0x8d5, 0x7f, 0x80);
 		/* PATH1_BAL_LEVEL */
 		cx18_av_and_or(cx, 0x8d5, ~0x7f, bal & 0x7f);
 	} else {
 		/* PATH1_BAL_LEFT */
 		cx18_av_and_or(cx, 0x8d5, 0x7f, 0x00);
 		/* PATH1_BAL_LEVEL */
 		cx18_av_and_or(cx, 0x8d5, ~0x7f, 0x80 - bal);
 	}
 }

 static int get_mute(struct cx18 *cx)
 {
 	/* check SRC1_MUTE_EN */
 	return cx18_av_read(cx, 0x8d3) & 0x2 ? 1 : 0;
 }

 static void set_mute(struct cx18 *cx, int mute)
 {
 	struct cx18_av_state *state = &cx->av_state;
 	u8 v;

 	if (state->aud_input > CX18_AV_AUDIO_SERIAL2) {
 		/* Must turn off microcontroller in order to mute sound.
 		 * Not sure if this is the best method, but it does work.
 		 * If the microcontroller is running, then it will undo any
 		 * changes to the mute register. */
 		v = cx18_av_read(cx, 0x803);
 		if (mute) {
 			/* disable microcontroller */
 			v &= ~0x10;
 			cx18_av_write_expect(cx, 0x803, v, v, 0x1f);
 			cx18_av_write(cx, 0x8d3, 0x1f);
 		} else {
 			/* enable microcontroller */
 			v |= 0x10;
 			cx18_av_write_expect(cx, 0x803, v, v, 0x1f);
 		}
 	} else {
 		/* SRC1_MUTE_EN */
 		cx18_av_and_or(cx, 0x8d3, ~0x2, mute ? 0x02 : 0x00);
 	}
 }

 int cx18_av_audio(struct cx18 *cx, unsigned int cmd, void *arg)
 {
 	struct cx18_av_state *state = &cx->av_state;
 	struct v4l2_control *ctrl = arg;
 	int retval;

 	switch (cmd) {
 	case VIDIOC_INT_AUDIO_CLOCK_FREQ:
 	{
 		u8 v;
 		if (state->aud_input > CX18_AV_AUDIO_SERIAL2) {
 			v = cx18_av_read(cx, 0x803) & ~0x10;
 			cx18_av_write_expect(cx, 0x803, v, v, 0x1f);
 			cx18_av_write(cx, 0x8d3, 0x1f);
 		}
 		v = cx18_av_read(cx, 0x810) | 0x1;
 		cx18_av_write_expect(cx, 0x810, v, v, 0x0f);

 		retval = set_audclk_freq(cx, *(u32 *)arg);

 		v = cx18_av_read(cx, 0x810) & ~0x1;
 		cx18_av_write_expect(cx, 0x810, v, v, 0x0f);
 		if (state->aud_input > CX18_AV_AUDIO_SERIAL2) {
 			v = cx18_av_read(cx, 0x803) | 0x10;
 			cx18_av_write_expect(cx, 0x803, v, v, 0x1f);
 		}
 		return retval;
 	}

 	case VIDIOC_G_CTRL:
 		switch (ctrl->id) {
 		case V4L2_CID_AUDIO_VOLUME:
 			ctrl->value = get_volume(cx);
 			break;
 		case V4L2_CID_AUDIO_BASS:
 			ctrl->value = get_bass(cx);
 			break;
 		case V4L2_CID_AUDIO_TREBLE:
 			ctrl->value = get_treble(cx);
 			break;
 		case V4L2_CID_AUDIO_BALANCE:
 			ctrl->value = get_balance(cx);
 			break;
 		case V4L2_CID_AUDIO_MUTE:
 			ctrl->value = get_mute(cx);
 			break;
 		default:
 			return -EINVAL;
 		}
 		break;

 	case VIDIOC_S_CTRL:
 		switch (ctrl->id) {
 		case V4L2_CID_AUDIO_VOLUME:
 			set_volume(cx, ctrl->value);
 			break;
 		case V4L2_CID_AUDIO_BASS:
 			set_bass(cx, ctrl->value);
 			break;
 		case V4L2_CID_AUDIO_TREBLE:
 			set_treble(cx, ctrl->value);
 			break;
 		case V4L2_CID_AUDIO_BALANCE:
 			set_balance(cx, ctrl->value);
 			break;
 		case V4L2_CID_AUDIO_MUTE:
 			set_mute(cx, ctrl->value);
 			break;
 		default:
 			return -EINVAL;
 		}
 		break;

 	default:
 		return -EINVAL;
 	}

 	return 0;
 }
	/*
	* cx18 ADEC audio functions
	*
	* Derived from cx25840-audio.c
	*
	* Copyright (C) 2007 Hans Verkuil <hverkuil@xs4all.nl>
	* Copyright (C) 2008 Andy Walls <awalls@radix.net>
	*
	* 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., 51 Franklin Street, Fifth Floor, Boston, MA
	* 02110-1301, USA.
	*/

	#include "cx18-driver.h"

	static int set_audclk_freq(struct cx18 *cx, u32 freq)
	{
	struct cx18_av_state *state = &cx->av_state;

	if (freq != 32000 && freq != 44100 && freq != 48000)
	return -EINVAL;

	/*
	* The PLL parameters are based on the external crystal frequency that
	* would ideally be:
	*
	* NTSC Color subcarrier freq * 8 =
	* 4.5 MHz/286 * 455/2 * 8 = 28.63636363... MHz
	*
	* The accidents of history and rationale that explain from where this
	* combination of magic numbers originate can be found in:
	*
	* [1] Abrahams, I. C., "Choice of Chrominance Subcarrier Frequency in
	* the NTSC Standards", Proceedings of the I-R-E, January 1954, pp 79-80
	*
	* [2] Abrahams, I. C., "The 'Frequency Interleaving' Principle in the
	* NTSC Standards", Proceedings of the I-R-E, January 1954, pp 81-83
	*
	* As Mike Bradley has rightly pointed out, it's not the exact crystal
	* frequency that matters, only that all parts of the driver and
	* firmware are using the same value (close to the ideal value).
	*
	* Since I have a strong suspicion that, if the firmware ever assumes a
	* crystal value at all, it will assume 28.636360 MHz, the crystal
	* freq used in calculations in this driver will be:
	*
	* xtal_freq = 28.636360 MHz
	*
	* an error of less than 0.13 ppm which is way, way better than any off
	* the shelf crystal will have for accuracy anyway.
	*
	* Below I aim to run the PLLs' VCOs near 400 MHz to minimze error.
	*
	* Many thanks to Jeff Campbell and Mike Bradley for their extensive
	* investigation, experimentation, testing, and suggested solutions of
	* of audio/video sync problems with SVideo and CVBS captures.
	*/

	if (state->aud_input > CX18_AV_AUDIO_SERIAL2) {
	switch (freq) {
	case 32000:
	/*
	* VID_PLL Integer = 0x0f, VID_PLL Post Divider = 0x04
	* AUX_PLL Integer = 0x0d, AUX PLL Post Divider = 0x20
	*/
	cx18_av_write4(cx, 0x108, 0x200d040f);

	/* VID_PLL Fraction = 0x2be2fe */
	/* xtal * 0xf.15f17f0/4 = 108 MHz: 432 MHz pre-postdiv*/
	cx18_av_write4(cx, 0x10c, 0x002be2fe);

	/* AUX_PLL Fraction = 0x176740c */
	/* xtal * 0xd.bb3a060/0x20 = 32000 * 384: 393 MHz p-pd*/
	cx18_av_write4(cx, 0x110, 0x0176740c);

	/* src3/4/6_ctl */
	/* 0x1.f77f = (4 * xtal/82/455) / 32000 /
	cx18_av_write4(cx, 0x900, 0x0801f77f);
	cx18_av_write4(cx, 0x904, 0x0801f77f);
	cx18_av_write4(cx, 0x90c, 0x0801f77f);

	/* SA_MCLK_SEL=1, SA_MCLK_DIV=0x20 */
	cx18_av_write(cx, 0x127, 0x60);

	/* AUD_COUNT = 0x2fff = 8 samples * 4 * 384 - 1 */
	cx18_av_write4(cx, 0x12c, 0x11202fff);

	/*
	* EN_AV_LOCK = 0
	* VID_COUNT = 0x0d2ef8 = 107999.000 * 8 =
	* ((8 samples/32,000) * (13,500,000 * 8) * 4 - 1) * 8
	*/
	cx18_av_write4(cx, 0x128, 0xa00d2ef8);
	break;

	case 44100:
	/*
	* VID_PLL Integer = 0x0f, VID_PLL Post Divider = 0x04
	* AUX_PLL Integer = 0x0e, AUX PLL Post Divider = 0x18
	*/
	cx18_av_write4(cx, 0x108, 0x180e040f);

	/* VID_PLL Fraction = 0x2be2fe */
	/* xtal * 0xf.15f17f0/4 = 108 MHz: 432 MHz pre-postdiv*/
	cx18_av_write4(cx, 0x10c, 0x002be2fe);

	/* AUX_PLL Fraction = 0x062a1f2 */
	/* xtal * 0xe.3150f90/0x18 = 44100 * 384: 406 MHz p-pd*/
	cx18_av_write4(cx, 0x110, 0x0062a1f2);

	/* src3/4/6_ctl */
	/* 0x1.6d59 = (4 * xtal/82/455) / 44100 /
	cx18_av_write4(cx, 0x900, 0x08016d59);
	cx18_av_write4(cx, 0x904, 0x08016d59);
	cx18_av_write4(cx, 0x90c, 0x08016d59);

	/* SA_MCLK_SEL=1, SA_MCLK_DIV=0x18 */
	cx18_av_write(cx, 0x127, 0x58);

	/* AUD_COUNT = 0x92ff = 49 samples * 2 * 384 - 1 */
	cx18_av_write4(cx, 0x12c, 0x112092ff);

	/*
	* EN_AV_LOCK = 0
	* VID_COUNT = 0x1d4bf8 = 239999.000 * 8 =
	* ((49 samples/44,100) * (13,500,000 * 8) * 2 - 1) * 8
	*/
	cx18_av_write4(cx, 0x128, 0xa01d4bf8);
	break;

	case 48000:
	/*
	* VID_PLL Integer = 0x0f, VID_PLL Post Divider = 0x04
	* AUX_PLL Integer = 0x0e, AUX PLL Post Divider = 0x16
	*/
	cx18_av_write4(cx, 0x108, 0x160e040f);

	/* VID_PLL Fraction = 0x2be2fe */
	/* xtal * 0xf.15f17f0/4 = 108 MHz: 432 MHz pre-postdiv*/
	cx18_av_write4(cx, 0x10c, 0x002be2fe);

	/* AUX_PLL Fraction = 0x05227ad */
	/* xtal * 0xe.2913d68/0x16 = 48000 * 384: 406 MHz p-pd*/
	cx18_av_write4(cx, 0x110, 0x005227ad);

	/* src3/4/6_ctl */
	/* 0x1.4faa = (4 * xtal/82/455) / 48000 /
	cx18_av_write4(cx, 0x900, 0x08014faa);
	cx18_av_write4(cx, 0x904, 0x08014faa);
	cx18_av_write4(cx, 0x90c, 0x08014faa);

	/* SA_MCLK_SEL=1, SA_MCLK_DIV=0x16 */
	cx18_av_write(cx, 0x127, 0x56);

	/* AUD_COUNT = 0x5fff = 4 samples * 16 * 384 - 1 */
	cx18_av_write4(cx, 0x12c, 0x11205fff);

	/*
	* EN_AV_LOCK = 0
	* VID_COUNT = 0x1193f8 = 143999.000 * 8 =
	* ((4 samples/48,000) * (13,500,000 * 8) * 16 - 1) * 8
	*/
	cx18_av_write4(cx, 0x128, 0xa01193f8);
	break;
	}
	} else {
	switch (freq) {
	case 32000:
	/*
	* VID_PLL Integer = 0x0f, VID_PLL Post Divider = 0x04
	* AUX_PLL Integer = 0x0d, AUX PLL Post Divider = 0x30
	*/
	cx18_av_write4(cx, 0x108, 0x300d040f);

	/* VID_PLL Fraction = 0x2be2fe */
	/* xtal * 0xf.15f17f0/4 = 108 MHz: 432 MHz pre-postdiv*/
	cx18_av_write4(cx, 0x10c, 0x002be2fe);

	/* AUX_PLL Fraction = 0x176740c */
	/* xtal * 0xd.bb3a060/0x30 = 32000 * 256: 393 MHz p-pd*/
	cx18_av_write4(cx, 0x110, 0x0176740c);

	/* src1_ctl */
	/* 0x1.0000 = 32000/32000 */
	cx18_av_write4(cx, 0x8f8, 0x08010000);

	/* src3/4/6_ctl */
	/* 0x2.0000 = 2 * (32000/32000) */
	cx18_av_write4(cx, 0x900, 0x08020000);
	cx18_av_write4(cx, 0x904, 0x08020000);
	cx18_av_write4(cx, 0x90c, 0x08020000);

	/* SA_MCLK_SEL=1, SA_MCLK_DIV=0x30 */
	cx18_av_write(cx, 0x127, 0x70);

	/* AUD_COUNT = 0x1fff = 8 samples * 4 * 256 - 1 */
	cx18_av_write4(cx, 0x12c, 0x11201fff);

	/*
	* EN_AV_LOCK = 0
	* VID_COUNT = 0x0d2ef8 = 107999.000 * 8 =
	* ((8 samples/32,000) * (13,500,000 * 8) * 4 - 1) * 8
	*/
	cx18_av_write4(cx, 0x128, 0xa00d2ef8);
	break;

	case 44100:
	/*
	* VID_PLL Integer = 0x0f, VID_PLL Post Divider = 0x04
	* AUX_PLL Integer = 0x0e, AUX PLL Post Divider = 0x24
	*/
	cx18_av_write4(cx, 0x108, 0x240e040f);

	/* VID_PLL Fraction = 0x2be2fe */
	/* xtal * 0xf.15f17f0/4 = 108 MHz: 432 MHz pre-postdiv*/
	cx18_av_write4(cx, 0x10c, 0x002be2fe);

	/* AUX_PLL Fraction = 0x062a1f2 */
	/* xtal * 0xe.3150f90/0x24 = 44100 * 256: 406 MHz p-pd*/
	cx18_av_write4(cx, 0x110, 0x0062a1f2);

	/* src1_ctl */
	/* 0x1.60cd = 44100/32000 */
	cx18_av_write4(cx, 0x8f8, 0x080160cd);

	/* src3/4/6_ctl */
	/* 0x1.7385 = 2 * (32000/44100) */
	cx18_av_write4(cx, 0x900, 0x08017385);
	cx18_av_write4(cx, 0x904, 0x08017385);
	cx18_av_write4(cx, 0x90c, 0x08017385);

	/* SA_MCLK_SEL=1, SA_MCLK_DIV=0x24 */
	cx18_av_write(cx, 0x127, 0x64);

	/* AUD_COUNT = 0x61ff = 49 samples * 2 * 256 - 1 */
	cx18_av_write4(cx, 0x12c, 0x112061ff);

	/*
	* EN_AV_LOCK = 0
	* VID_COUNT = 0x1d4bf8 = 239999.000 * 8 =
	* ((49 samples/44,100) * (13,500,000 * 8) * 2 - 1) * 8
	*/
	cx18_av_write4(cx, 0x128, 0xa01d4bf8);
	break;

	case 48000:
	/*
	* VID_PLL Integer = 0x0f, VID_PLL Post Divider = 0x04
	* AUX_PLL Integer = 0x0d, AUX PLL Post Divider = 0x20
	*/
	cx18_av_write4(cx, 0x108, 0x200d040f);

	/* VID_PLL Fraction = 0x2be2fe */
	/* xtal * 0xf.15f17f0/4 = 108 MHz: 432 MHz pre-postdiv*/
	cx18_av_write4(cx, 0x10c, 0x002be2fe);

	/* AUX_PLL Fraction = 0x176740c */
	/* xtal * 0xd.bb3a060/0x20 = 48000 * 256: 393 MHz p-pd*/
	cx18_av_write4(cx, 0x110, 0x0176740c);

	/* src1_ctl */
	/* 0x1.8000 = 48000/32000 */
	cx18_av_write4(cx, 0x8f8, 0x08018000);

	/* src3/4/6_ctl */
	/* 0x1.5555 = 2 * (32000/48000) */
	cx18_av_write4(cx, 0x900, 0x08015555);
	cx18_av_write4(cx, 0x904, 0x08015555);
	cx18_av_write4(cx, 0x90c, 0x08015555);

	/* SA_MCLK_SEL=1, SA_MCLK_DIV=0x20 */
	cx18_av_write(cx, 0x127, 0x60);

	/* AUD_COUNT = 0x3fff = 4 samples * 16 * 256 - 1 */
	cx18_av_write4(cx, 0x12c, 0x11203fff);

	/*
	* EN_AV_LOCK = 0
	* VID_COUNT = 0x1193f8 = 143999.000 * 8 =
	* ((4 samples/48,000) * (13,500,000 * 8) * 16 - 1) * 8
	*/
	cx18_av_write4(cx, 0x128, 0xa01193f8);
	break;
	}
	}

	state->audclk_freq = freq;

	return 0;
	}

	void cx18_av_audio_set_path(struct cx18 *cx)
	{
	struct cx18_av_state *state = &cx->av_state;
	u8 v;

	/* stop microcontroller */
	v = cx18_av_read(cx, 0x803) & ~0x10;
	cx18_av_write_expect(cx, 0x803, v, v, 0x1f);

	/* assert soft reset */
	v = cx18_av_read(cx, 0x810) \| 0x01;
	cx18_av_write_expect(cx, 0x810, v, v, 0x0f);

	/* Mute everything to prevent the PFFT! */
	cx18_av_write(cx, 0x8d3, 0x1f);

	if (state->aud_input <= CX18_AV_AUDIO_SERIAL2) {
	/* Set Path1 to Serial Audio Input */
	cx18_av_write4(cx, 0x8d0, 0x01011012);

	/* The microcontroller should not be started for the
	* non-tuner inputs: autodetection is specific for
	* TV audio. */
	} else {
	/* Set Path1 to Analog Demod Main Channel */
	cx18_av_write4(cx, 0x8d0, 0x1f063870);
	}

	set_audclk_freq(cx, state->audclk_freq);

	/* deassert soft reset */
	v = cx18_av_read(cx, 0x810) & ~0x01;
	cx18_av_write_expect(cx, 0x810, v, v, 0x0f);

	if (state->aud_input > CX18_AV_AUDIO_SERIAL2) {
	/* When the microcontroller detects the
	* audio format, it will unmute the lines */
	v = cx18_av_read(cx, 0x803) \| 0x10;
	cx18_av_write_expect(cx, 0x803, v, v, 0x1f);
	}
	}

	static int get_volume(struct cx18 *cx)
	{
	/* Volume runs +18dB to -96dB in 1/2dB steps
	* change to fit the msp3400 -114dB to +12dB range */

	/* check PATH1_VOLUME */
	int vol = 228 - cx18_av_read(cx, 0x8d4);
	vol = (vol / 2) + 23;
	return vol << 9;
	}

	static void set_volume(struct cx18 *cx, int volume)
	{
	/* First convert the volume to msp3400 values (0-127) */
	int vol = volume >> 9;
	/* now scale it up to cx18_av values
	* -114dB to -96dB maps to 0
	* this should be 19, but in my testing that was 4dB too loud */
	if (vol <= 23)
	vol = 0;
	else
	vol -= 23;

	/* PATH1_VOLUME */
	cx18_av_write(cx, 0x8d4, 228 - (vol * 2));
	}

	static int get_bass(struct cx18 *cx)
	{
	/* bass is 49 steps +12dB to -12dB */

	/* check PATH1_EQ_BASS_VOL */
	int bass = cx18_av_read(cx, 0x8d9) & 0x3f;
	bass = (((48 - bass) * 0xffff) + 47) / 48;
	return bass;
	}

	static void set_bass(struct cx18 *cx, int bass)
	{
	/* PATH1_EQ_BASS_VOL */
	cx18_av_and_or(cx, 0x8d9, ~0x3f, 48 - (bass * 48 / 0xffff));
	}

	static int get_treble(struct cx18 *cx)
	{
	/* treble is 49 steps +12dB to -12dB */

	/* check PATH1_EQ_TREBLE_VOL */
	int treble = cx18_av_read(cx, 0x8db) & 0x3f;
	treble = (((48 - treble) * 0xffff) + 47) / 48;
	return treble;
	}

	static void set_treble(struct cx18 *cx, int treble)
	{
	/* PATH1_EQ_TREBLE_VOL */
	cx18_av_and_or(cx, 0x8db, ~0x3f, 48 - (treble * 48 / 0xffff));
	}

	static int get_balance(struct cx18 *cx)
	{
	/* balance is 7 bit, 0 to -96dB */

	/* check PATH1_BAL_LEVEL */
	int balance = cx18_av_read(cx, 0x8d5) & 0x7f;
	/* check PATH1_BAL_LEFT */
	if ((cx18_av_read(cx, 0x8d5) & 0x80) == 0)
	balance = 0x80 - balance;
	else
	balance = 0x80 + balance;
	return balance << 8;
	}

	static void set_balance(struct cx18 *cx, int balance)
	{
	int bal = balance >> 8;
	if (bal > 0x80) {
	/* PATH1_BAL_LEFT */
	cx18_av_and_or(cx, 0x8d5, 0x7f, 0x80);
	/* PATH1_BAL_LEVEL */
	cx18_av_and_or(cx, 0x8d5, ~0x7f, bal & 0x7f);
	} else {
	/* PATH1_BAL_LEFT */
	cx18_av_and_or(cx, 0x8d5, 0x7f, 0x00);
	/* PATH1_BAL_LEVEL */
	cx18_av_and_or(cx, 0x8d5, ~0x7f, 0x80 - bal);
	}
	}

	static int get_mute(struct cx18 *cx)
	{
	/* check SRC1_MUTE_EN */
	return cx18_av_read(cx, 0x8d3) & 0x2 ? 1 : 0;
	}

	static void set_mute(struct cx18 *cx, int mute)
	{
	struct cx18_av_state *state = &cx->av_state;
	u8 v;

	if (state->aud_input > CX18_AV_AUDIO_SERIAL2) {
	/* Must turn off microcontroller in order to mute sound.
	* Not sure if this is the best method, but it does work.
	* If the microcontroller is running, then it will undo any
	* changes to the mute register. */
	v = cx18_av_read(cx, 0x803);
	if (mute) {
	/* disable microcontroller */
	v &= ~0x10;
	cx18_av_write_expect(cx, 0x803, v, v, 0x1f);
	cx18_av_write(cx, 0x8d3, 0x1f);
	} else {
	/* enable microcontroller */
	v \|= 0x10;
	cx18_av_write_expect(cx, 0x803, v, v, 0x1f);
	}
	} else {
	/* SRC1_MUTE_EN */
	cx18_av_and_or(cx, 0x8d3, ~0x2, mute ? 0x02 : 0x00);
	}
	}

	int cx18_av_audio(struct cx18 cx, unsigned int cmd, void arg)
	{
	struct cx18_av_state *state = &cx->av_state;
	struct v4l2_control *ctrl = arg;
	int retval;

	switch (cmd) {
	case VIDIOC_INT_AUDIO_CLOCK_FREQ:
	{
	u8 v;
	if (state->aud_input > CX18_AV_AUDIO_SERIAL2) {
	v = cx18_av_read(cx, 0x803) & ~0x10;
	cx18_av_write_expect(cx, 0x803, v, v, 0x1f);
	cx18_av_write(cx, 0x8d3, 0x1f);
	}
	v = cx18_av_read(cx, 0x810) \| 0x1;
	cx18_av_write_expect(cx, 0x810, v, v, 0x0f);

	retval = set_audclk_freq(cx, (u32 )arg);

	v = cx18_av_read(cx, 0x810) & ~0x1;
	cx18_av_write_expect(cx, 0x810, v, v, 0x0f);
	if (state->aud_input > CX18_AV_AUDIO_SERIAL2) {
	v = cx18_av_read(cx, 0x803) \| 0x10;
	cx18_av_write_expect(cx, 0x803, v, v, 0x1f);
	}
	return retval;
	}

	case VIDIOC_G_CTRL:
	switch (ctrl->id) {
	case V4L2_CID_AUDIO_VOLUME:
	ctrl->value = get_volume(cx);
	break;
	case V4L2_CID_AUDIO_BASS:
	ctrl->value = get_bass(cx);
	break;
	case V4L2_CID_AUDIO_TREBLE:
	ctrl->value = get_treble(cx);
	break;
	case V4L2_CID_AUDIO_BALANCE:
	ctrl->value = get_balance(cx);
	break;
	case V4L2_CID_AUDIO_MUTE:
	ctrl->value = get_mute(cx);
	break;
	default:
	return -EINVAL;
	}
	break;

	case VIDIOC_S_CTRL:
	switch (ctrl->id) {
	case V4L2_CID_AUDIO_VOLUME:
	set_volume(cx, ctrl->value);
	break;
	case V4L2_CID_AUDIO_BASS:
	set_bass(cx, ctrl->value);
	break;
	case V4L2_CID_AUDIO_TREBLE:
	set_treble(cx, ctrl->value);
	break;
	case V4L2_CID_AUDIO_BALANCE:
	set_balance(cx, ctrl->value);
	break;
	case V4L2_CID_AUDIO_MUTE:
	set_mute(cx, ctrl->value);
	break;
	default:
	return -EINVAL;
	}
	break;

	default:
	return -EINVAL;
	}

	return 0;
	}