240 lines
6.5 KiB
C
240 lines
6.5 KiB
C
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/*
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* rt5677-spi.c -- RT5677 ALSA SoC audio codec driver
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*
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* Copyright 2013 Realtek Semiconductor Corp.
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* Author: Oder Chiou <oder_chiou@realtek.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/input.h>
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#include <linux/spi/spi.h>
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#include <linux/device.h>
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/slab.h>
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#include <linux/gpio.h>
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#include <linux/sched.h>
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#include <linux/kthread.h>
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#include <linux/uaccess.h>
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#include <linux/miscdevice.h>
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#include <linux/regulator/consumer.h>
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#include <linux/pm_qos.h>
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#include <linux/sysfs.h>
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#include <linux/clk.h>
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#include <linux/firmware.h>
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#include "rt5677-spi.h"
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#define RT5677_SPI_BURST_LEN 240
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#define RT5677_SPI_HEADER 5
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#define RT5677_SPI_FREQ 6000000
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/* The AddressPhase and DataPhase of SPI commands are MSB first on the wire.
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* DataPhase word size of 16-bit commands is 2 bytes.
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* DataPhase word size of 32-bit commands is 4 bytes.
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* DataPhase word size of burst commands is 8 bytes.
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* The DSP CPU is little-endian.
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*/
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#define RT5677_SPI_WRITE_BURST 0x5
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#define RT5677_SPI_READ_BURST 0x4
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#define RT5677_SPI_WRITE_32 0x3
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#define RT5677_SPI_READ_32 0x2
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#define RT5677_SPI_WRITE_16 0x1
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#define RT5677_SPI_READ_16 0x0
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static struct spi_device *g_spi;
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static DEFINE_MUTEX(spi_mutex);
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/* Select a suitable transfer command for the next transfer to ensure
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* the transfer address is always naturally aligned while minimizing
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* the total number of transfers required.
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*
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* 3 transfer commands are available:
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* RT5677_SPI_READ/WRITE_16: Transfer 2 bytes
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* RT5677_SPI_READ/WRITE_32: Transfer 4 bytes
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* RT5677_SPI_READ/WRITE_BURST: Transfer any multiples of 8 bytes
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*
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* Note:
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* 16 Bit writes and reads are restricted to the address range
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* 0x18020000 ~ 0x18021000
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*
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* For example, reading 256 bytes at 0x60030004 uses the following commands:
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* 0x60030004 RT5677_SPI_READ_32 4 bytes
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* 0x60030008 RT5677_SPI_READ_BURST 240 bytes
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* 0x600300F8 RT5677_SPI_READ_BURST 8 bytes
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* 0x60030100 RT5677_SPI_READ_32 4 bytes
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*
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* Input:
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* @read: true for read commands; false for write commands
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* @align: alignment of the next transfer address
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* @remain: number of bytes remaining to transfer
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*
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* Output:
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* @len: number of bytes to transfer with the selected command
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* Returns the selected command
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*/
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static u8 rt5677_spi_select_cmd(bool read, u32 align, u32 remain, u32 *len)
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{
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u8 cmd;
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if (align == 4 || remain <= 4) {
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cmd = RT5677_SPI_READ_32;
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*len = 4;
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} else {
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cmd = RT5677_SPI_READ_BURST;
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*len = (((remain - 1) >> 3) + 1) << 3;
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*len = min_t(u32, *len, RT5677_SPI_BURST_LEN);
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}
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return read ? cmd : cmd + 1;
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}
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/* Copy dstlen bytes from src to dst, while reversing byte order for each word.
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* If srclen < dstlen, zeros are padded.
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*/
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static void rt5677_spi_reverse(u8 *dst, u32 dstlen, const u8 *src, u32 srclen)
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{
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u32 w, i, si;
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u32 word_size = min_t(u32, dstlen, 8);
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for (w = 0; w < dstlen; w += word_size) {
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for (i = 0; i < word_size; i++) {
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si = w + word_size - i - 1;
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dst[w + i] = si < srclen ? src[si] : 0;
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}
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}
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}
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/* Read DSP address space using SPI. addr and len have to be 4-byte aligned. */
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int rt5677_spi_read(u32 addr, void *rxbuf, size_t len)
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{
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u32 offset;
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int status = 0;
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struct spi_transfer t[2];
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struct spi_message m;
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/* +4 bytes is for the DummyPhase following the AddressPhase */
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u8 header[RT5677_SPI_HEADER + 4];
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u8 body[RT5677_SPI_BURST_LEN];
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u8 spi_cmd;
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u8 *cb = rxbuf;
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if (!g_spi)
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return -ENODEV;
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if ((addr & 3) || (len & 3)) {
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dev_err(&g_spi->dev, "Bad read align 0x%x(%zu)\n", addr, len);
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return -EACCES;
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}
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memset(t, 0, sizeof(t));
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t[0].tx_buf = header;
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t[0].len = sizeof(header);
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t[0].speed_hz = RT5677_SPI_FREQ;
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t[1].rx_buf = body;
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t[1].speed_hz = RT5677_SPI_FREQ;
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spi_message_init_with_transfers(&m, t, ARRAY_SIZE(t));
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for (offset = 0; offset < len; offset += t[1].len) {
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spi_cmd = rt5677_spi_select_cmd(true, (addr + offset) & 7,
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len - offset, &t[1].len);
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/* Construct SPI message header */
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header[0] = spi_cmd;
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header[1] = ((addr + offset) & 0xff000000) >> 24;
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header[2] = ((addr + offset) & 0x00ff0000) >> 16;
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header[3] = ((addr + offset) & 0x0000ff00) >> 8;
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header[4] = ((addr + offset) & 0x000000ff) >> 0;
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mutex_lock(&spi_mutex);
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status |= spi_sync(g_spi, &m);
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mutex_unlock(&spi_mutex);
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/* Copy data back to caller buffer */
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rt5677_spi_reverse(cb + offset, t[1].len, body, t[1].len);
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}
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return status;
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}
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EXPORT_SYMBOL_GPL(rt5677_spi_read);
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/* Write DSP address space using SPI. addr has to be 4-byte aligned.
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* If len is not 4-byte aligned, then extra zeros are written at the end
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* as padding.
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*/
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int rt5677_spi_write(u32 addr, const void *txbuf, size_t len)
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{
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u32 offset;
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int status = 0;
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struct spi_transfer t;
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struct spi_message m;
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/* +1 byte is for the DummyPhase following the DataPhase */
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u8 buf[RT5677_SPI_HEADER + RT5677_SPI_BURST_LEN + 1];
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u8 *body = buf + RT5677_SPI_HEADER;
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u8 spi_cmd;
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const u8 *cb = txbuf;
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if (!g_spi)
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return -ENODEV;
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if (addr & 3) {
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dev_err(&g_spi->dev, "Bad write align 0x%x(%zu)\n", addr, len);
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return -EACCES;
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}
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memset(&t, 0, sizeof(t));
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t.tx_buf = buf;
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t.speed_hz = RT5677_SPI_FREQ;
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spi_message_init_with_transfers(&m, &t, 1);
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for (offset = 0; offset < len;) {
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spi_cmd = rt5677_spi_select_cmd(false, (addr + offset) & 7,
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len - offset, &t.len);
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/* Construct SPI message header */
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buf[0] = spi_cmd;
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buf[1] = ((addr + offset) & 0xff000000) >> 24;
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buf[2] = ((addr + offset) & 0x00ff0000) >> 16;
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buf[3] = ((addr + offset) & 0x0000ff00) >> 8;
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buf[4] = ((addr + offset) & 0x000000ff) >> 0;
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/* Fetch data from caller buffer */
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rt5677_spi_reverse(body, t.len, cb + offset, len - offset);
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offset += t.len;
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t.len += RT5677_SPI_HEADER + 1;
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mutex_lock(&spi_mutex);
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status |= spi_sync(g_spi, &m);
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mutex_unlock(&spi_mutex);
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}
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return status;
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}
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EXPORT_SYMBOL_GPL(rt5677_spi_write);
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int rt5677_spi_write_firmware(u32 addr, const struct firmware *fw)
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{
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return rt5677_spi_write(addr, fw->data, fw->size);
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}
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EXPORT_SYMBOL_GPL(rt5677_spi_write_firmware);
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static int rt5677_spi_probe(struct spi_device *spi)
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{
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g_spi = spi;
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return 0;
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}
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static struct spi_driver rt5677_spi_driver = {
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.driver = {
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.name = "rt5677",
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},
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.probe = rt5677_spi_probe,
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};
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module_spi_driver(rt5677_spi_driver);
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MODULE_DESCRIPTION("ASoC RT5677 SPI driver");
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MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>");
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MODULE_LICENSE("GPL v2");
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