linux/sound/drivers/vx/vx_uer.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for Digigram VX soundcards
 *
 * IEC958 stuff
 *
 * Copyright (c) 2002 by Takashi Iwai <[email protected]>
 */

#include <linux/delay.h>
#include <sound/core.h>
#include <sound/vx_core.h>
#include "vx_cmd.h"


/*
 * vx_modify_board_clock - tell the board that its clock has been modified
 * @sync: DSP needs to resynchronize its FIFO
 */
static int vx_modify_board_clock(struct vx_core *chip, int sync)
{ … }

/*
 * vx_modify_board_inputs - resync audio inputs
 */
static int vx_modify_board_inputs(struct vx_core *chip)
{ … }

/*
 * vx_read_one_cbit - read one bit from UER config
 * @index: the bit index
 * returns 0 or 1.
 */
static int vx_read_one_cbit(struct vx_core *chip, int index)
{ … }

/*
 * vx_write_one_cbit - write one bit to UER config
 * @index: the bit index
 * @val: bit value, 0 or 1
 */
static void vx_write_one_cbit(struct vx_core *chip, int index, int val)
{ … }

/*
 * vx_read_uer_status - read the current UER status
 * @mode: pointer to store the UER mode, VX_UER_MODE_XXX
 *
 * returns the frequency of UER, or 0 if not sync,
 * or a negative error code.
 */
static int vx_read_uer_status(struct vx_core *chip, unsigned int *mode)
{ … }


/*
 * compute the sample clock value from frequency
 *
 * The formula is as follows:
 *
 *    HexFreq = (dword) ((double) ((double) 28224000 / (double) Frequency))
 *    switch ( HexFreq & 0x00000F00 )
 *    case 0x00000100: ;
 *    case 0x00000200:
 *    case 0x00000300: HexFreq -= 0x00000201 ;
 *    case 0x00000400:
 *    case 0x00000500:
 *    case 0x00000600:
 *    case 0x00000700: HexFreq = (dword) (((double) 28224000 / (double) (Frequency*2)) - 1)
 *    default        : HexFreq = (dword) ((double) 28224000 / (double) (Frequency*4)) - 0x000001FF
 */

static int vx_calc_clock_from_freq(struct vx_core *chip, int freq)
{ … }


/*
 * vx_change_clock_source - change the clock source
 * @source: the new source
 */
static void vx_change_clock_source(struct vx_core *chip, int source)
{ … }


/*
 * set the internal clock
 */
void vx_set_internal_clock(struct vx_core *chip, unsigned int freq)
{ … }


/*
 * set the iec958 status bits
 * @bits: 32-bit status bits
 */
void vx_set_iec958_status(struct vx_core *chip, unsigned int bits)
{ … }


/*
 * vx_set_clock - change the clock and audio source if necessary
 */
int vx_set_clock(struct vx_core *chip, unsigned int freq)
{ … }


/*
 * vx_change_frequency - called from interrupt handler
 */
int vx_change_frequency(struct vx_core *chip)
{ … }