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/*
* rt5677-spi.c -- RT5677 ALSA SoC audio codec driver
*
* Copyright 2013 Realtek Semiconductor Corp.
* Author: Oder Chiou <oder_chiou@realtek.com>
*
* 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.
*/
#include <linux/module.h>
#include <linux/input.h>
#include <linux/spi/spi.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/gpio.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <linux/regulator/consumer.h>
#include <linux/pm_qos.h>
#include <linux/sysfs.h>
#include <linux/clk.h>
#include <linux/firmware.h>
#include "rt5677-spi.h"
#define RT5677_SPI_BURST_LEN 240
#define RT5677_SPI_HEADER 5
#define RT5677_SPI_FREQ 6000000
/* The AddressPhase and DataPhase of SPI commands are MSB first on the wire.
* DataPhase word size of 16-bit commands is 2 bytes.
* DataPhase word size of 32-bit commands is 4 bytes.
* DataPhase word size of burst commands is 8 bytes.
* The DSP CPU is little-endian.
*/
#define RT5677_SPI_WRITE_BURST 0x5
#define RT5677_SPI_READ_BURST 0x4
#define RT5677_SPI_WRITE_32 0x3
#define RT5677_SPI_READ_32 0x2
#define RT5677_SPI_WRITE_16 0x1
#define RT5677_SPI_READ_16 0x0
static struct spi_device *g_spi;
static DEFINE_MUTEX(spi_mutex);
/* Select a suitable transfer command for the next transfer to ensure
* the transfer address is always naturally aligned while minimizing
* the total number of transfers required.
*
* 3 transfer commands are available:
* RT5677_SPI_READ/WRITE_16: Transfer 2 bytes
* RT5677_SPI_READ/WRITE_32: Transfer 4 bytes
* RT5677_SPI_READ/WRITE_BURST: Transfer any multiples of 8 bytes
*
* For example, reading 260 bytes at 0x60030002 uses the following commands:
* 0x60030002 RT5677_SPI_READ_16 2 bytes
* 0x60030004 RT5677_SPI_READ_32 4 bytes
* 0x60030008 RT5677_SPI_READ_BURST 240 bytes
* 0x600300F8 RT5677_SPI_READ_BURST 8 bytes
* 0x60030100 RT5677_SPI_READ_32 4 bytes
* 0x60030104 RT5677_SPI_READ_16 2 bytes
*
* Input:
* @read: true for read commands; false for write commands
* @align: alignment of the next transfer address
* @remain: number of bytes remaining to transfer
*
* Output:
* @len: number of bytes to transfer with the selected command
* Returns the selected command
*/
static u8 rt5677_spi_select_cmd(bool read, u32 align, u32 remain, u32 *len)
{
u8 cmd;
if (align == 2 || align == 6 || remain == 2) {
cmd = RT5677_SPI_READ_16;
*len = 2;
} else if (align == 4 || remain <= 6) {
cmd = RT5677_SPI_READ_32;
*len = 4;
} else {
cmd = RT5677_SPI_READ_BURST;
*len = min_t(u32, remain & ~7, RT5677_SPI_BURST_LEN);
}
return read ? cmd : cmd + 1;
}
/* Copy dstlen bytes from src to dst, while reversing byte order for each word.
* If srclen < dstlen, zeros are padded.
*/
static void rt5677_spi_reverse(u8 *dst, u32 dstlen, const u8 *src, u32 srclen)
{
u32 w, i, si;
u32 word_size = min_t(u32, dstlen, 8);
for (w = 0; w < dstlen; w += word_size) {
for (i = 0; i < word_size; i++) {
si = w + word_size - i - 1;
dst[w + i] = si < srclen ? src[si] : 0;
}
}
}
/* Read DSP address space using SPI. addr and len have to be 2-byte aligned. */
int rt5677_spi_read(u32 addr, void *rxbuf, size_t len)
{
u32 offset;
int status = 0;
struct spi_transfer t[2];
struct spi_message m;
/* +4 bytes is for the DummyPhase following the AddressPhase */
u8 header[RT5677_SPI_HEADER + 4];
u8 body[RT5677_SPI_BURST_LEN];
u8 spi_cmd;
u8 *cb = rxbuf;
if (!g_spi)
return -ENODEV;
if ((addr & 1) || (len & 1)) {
dev_err(&g_spi->dev, "Bad read align 0x%x(%zu)\n", addr, len);
return -EACCES;
}
memset(t, 0, sizeof(t));
t[0].tx_buf = header;
t[0].len = sizeof(header);
t[0].speed_hz = RT5677_SPI_FREQ;
t[1].rx_buf = body;
t[1].speed_hz = RT5677_SPI_FREQ;
spi_message_init_with_transfers(&m, t, ARRAY_SIZE(t));
for (offset = 0; offset < len; offset += t[1].len) {
spi_cmd = rt5677_spi_select_cmd(true, (addr + offset) & 7,
len - offset, &t[1].len);
/* Construct SPI message header */
header[0] = spi_cmd;
header[1] = ((addr + offset) & 0xff000000) >> 24;
header[2] = ((addr + offset) & 0x00ff0000) >> 16;
header[3] = ((addr + offset) & 0x0000ff00) >> 8;
header[4] = ((addr + offset) & 0x000000ff) >> 0;
mutex_lock(&spi_mutex);
status |= spi_sync(g_spi, &m);
mutex_unlock(&spi_mutex);
/* Copy data back to caller buffer */
rt5677_spi_reverse(cb + offset, t[1].len, body, t[1].len);
}
return status;
}
EXPORT_SYMBOL_GPL(rt5677_spi_read);
/* Write DSP address space using SPI. addr has to be 2-byte aligned.
* If len is not 2-byte aligned, an extra byte of zero is written at the end
* as padding.
*/
int rt5677_spi_write(u32 addr, const void *txbuf, size_t len)
{
u32 offset, len_with_pad = len;
int status = 0;
struct spi_transfer t;
struct spi_message m;
/* +1 byte is for the DummyPhase following the DataPhase */
u8 buf[RT5677_SPI_HEADER + RT5677_SPI_BURST_LEN + 1];
u8 *body = buf + RT5677_SPI_HEADER;
u8 spi_cmd;
const u8 *cb = txbuf;
if (!g_spi)
return -ENODEV;
if (addr & 1) {
dev_err(&g_spi->dev, "Bad write align 0x%x(%zu)\n", addr, len);
return -EACCES;
}
if (len & 1)
len_with_pad = len + 1;
memset(&t, 0, sizeof(t));
t.tx_buf = buf;
t.speed_hz = RT5677_SPI_FREQ;
spi_message_init_with_transfers(&m, &t, 1);
for (offset = 0; offset < len_with_pad;) {
spi_cmd = rt5677_spi_select_cmd(false, (addr + offset) & 7,
len_with_pad - offset, &t.len);
/* Construct SPI message header */
buf[0] = spi_cmd;
buf[1] = ((addr + offset) & 0xff000000) >> 24;
buf[2] = ((addr + offset) & 0x00ff0000) >> 16;
buf[3] = ((addr + offset) & 0x0000ff00) >> 8;
buf[4] = ((addr + offset) & 0x000000ff) >> 0;
/* Fetch data from caller buffer */
rt5677_spi_reverse(body, t.len, cb + offset, len - offset);
offset += t.len;
t.len += RT5677_SPI_HEADER + 1;
mutex_lock(&spi_mutex);
status |= spi_sync(g_spi, &m);
mutex_unlock(&spi_mutex);
}
return status;
}
EXPORT_SYMBOL_GPL(rt5677_spi_write);
int rt5677_spi_write_firmware(u32 addr, const struct firmware *fw)
{
return rt5677_spi_write(addr, fw->data, fw->size);
}
EXPORT_SYMBOL_GPL(rt5677_spi_write_firmware);
static int rt5677_spi_probe(struct spi_device *spi)
{
g_spi = spi;
return 0;
}
static struct spi_driver rt5677_spi_driver = {
.driver = {
.name = "rt5677",
},
.probe = rt5677_spi_probe,
};
module_spi_driver(rt5677_spi_driver);
MODULE_DESCRIPTION("ASoC RT5677 SPI driver");
MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>");
MODULE_LICENSE("GPL v2");
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