2 * rt5677-spi.c -- RT5677 ALSA SoC audio codec driver
4 * Copyright 2013 Realtek Semiconductor Corp.
5 * Author: Oder Chiou <oder_chiou@realtek.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/module.h>
13 #include <linux/input.h>
14 #include <linux/spi/spi.h>
15 #include <linux/device.h>
16 #include <linux/init.h>
17 #include <linux/delay.h>
18 #include <linux/interrupt.h>
19 #include <linux/irq.h>
20 #include <linux/slab.h>
21 #include <linux/sched.h>
22 #include <linux/uaccess.h>
23 #include <linux/regulator/consumer.h>
24 #include <linux/pm_qos.h>
25 #include <linux/sysfs.h>
26 #include <linux/clk.h>
27 #include <linux/firmware.h>
29 #include "rt5677-spi.h"
31 #define RT5677_SPI_BURST_LEN 240
32 #define RT5677_SPI_HEADER 5
33 #define RT5677_SPI_FREQ 6000000
35 /* The AddressPhase and DataPhase of SPI commands are MSB first on the wire.
36 * DataPhase word size of 16-bit commands is 2 bytes.
37 * DataPhase word size of 32-bit commands is 4 bytes.
38 * DataPhase word size of burst commands is 8 bytes.
39 * The DSP CPU is little-endian.
41 #define RT5677_SPI_WRITE_BURST 0x5
42 #define RT5677_SPI_READ_BURST 0x4
43 #define RT5677_SPI_WRITE_32 0x3
44 #define RT5677_SPI_READ_32 0x2
45 #define RT5677_SPI_WRITE_16 0x1
46 #define RT5677_SPI_READ_16 0x0
48 static struct spi_device *g_spi;
49 static DEFINE_MUTEX(spi_mutex);
51 /* Select a suitable transfer command for the next transfer to ensure
52 * the transfer address is always naturally aligned while minimizing
53 * the total number of transfers required.
55 * 3 transfer commands are available:
56 * RT5677_SPI_READ/WRITE_16: Transfer 2 bytes
57 * RT5677_SPI_READ/WRITE_32: Transfer 4 bytes
58 * RT5677_SPI_READ/WRITE_BURST: Transfer any multiples of 8 bytes
60 * For example, reading 260 bytes at 0x60030002 uses the following commands:
61 * 0x60030002 RT5677_SPI_READ_16 2 bytes
62 * 0x60030004 RT5677_SPI_READ_32 4 bytes
63 * 0x60030008 RT5677_SPI_READ_BURST 240 bytes
64 * 0x600300F8 RT5677_SPI_READ_BURST 8 bytes
65 * 0x60030100 RT5677_SPI_READ_32 4 bytes
66 * 0x60030104 RT5677_SPI_READ_16 2 bytes
69 * @read: true for read commands; false for write commands
70 * @align: alignment of the next transfer address
71 * @remain: number of bytes remaining to transfer
74 * @len: number of bytes to transfer with the selected command
75 * Returns the selected command
77 static u8 rt5677_spi_select_cmd(bool read, u32 align, u32 remain, u32 *len)
81 if (align == 2 || align == 6 || remain == 2) {
82 cmd = RT5677_SPI_READ_16;
84 } else if (align == 4 || remain <= 6) {
85 cmd = RT5677_SPI_READ_32;
88 cmd = RT5677_SPI_READ_BURST;
89 *len = min_t(u32, remain & ~7, RT5677_SPI_BURST_LEN);
91 return read ? cmd : cmd + 1;
94 /* Copy dstlen bytes from src to dst, while reversing byte order for each word.
95 * If srclen < dstlen, zeros are padded.
97 static void rt5677_spi_reverse(u8 *dst, u32 dstlen, const u8 *src, u32 srclen)
100 u32 word_size = min_t(u32, dstlen, 8);
102 for (w = 0; w < dstlen; w += word_size) {
103 for (i = 0; i < word_size; i++) {
104 si = w + word_size - i - 1;
105 dst[w + i] = si < srclen ? src[si] : 0;
110 /* Read DSP address space using SPI. addr and len have to be 2-byte aligned. */
111 int rt5677_spi_read(u32 addr, void *rxbuf, size_t len)
115 struct spi_transfer t[2];
116 struct spi_message m;
117 /* +4 bytes is for the DummyPhase following the AddressPhase */
118 u8 header[RT5677_SPI_HEADER + 4];
119 u8 body[RT5677_SPI_BURST_LEN];
126 if ((addr & 1) || (len & 1)) {
127 dev_err(&g_spi->dev, "Bad read align 0x%x(%zu)\n", addr, len);
131 memset(t, 0, sizeof(t));
132 t[0].tx_buf = header;
133 t[0].len = sizeof(header);
134 t[0].speed_hz = RT5677_SPI_FREQ;
136 t[1].speed_hz = RT5677_SPI_FREQ;
137 spi_message_init_with_transfers(&m, t, ARRAY_SIZE(t));
139 for (offset = 0; offset < len; offset += t[1].len) {
140 spi_cmd = rt5677_spi_select_cmd(true, (addr + offset) & 7,
141 len - offset, &t[1].len);
143 /* Construct SPI message header */
145 header[1] = ((addr + offset) & 0xff000000) >> 24;
146 header[2] = ((addr + offset) & 0x00ff0000) >> 16;
147 header[3] = ((addr + offset) & 0x0000ff00) >> 8;
148 header[4] = ((addr + offset) & 0x000000ff) >> 0;
150 mutex_lock(&spi_mutex);
151 status |= spi_sync(g_spi, &m);
152 mutex_unlock(&spi_mutex);
154 /* Copy data back to caller buffer */
155 rt5677_spi_reverse(cb + offset, t[1].len, body, t[1].len);
159 EXPORT_SYMBOL_GPL(rt5677_spi_read);
161 /* Write DSP address space using SPI. addr has to be 2-byte aligned.
162 * If len is not 2-byte aligned, an extra byte of zero is written at the end
165 int rt5677_spi_write(u32 addr, const void *txbuf, size_t len)
167 u32 offset, len_with_pad = len;
169 struct spi_transfer t;
170 struct spi_message m;
171 /* +1 byte is for the DummyPhase following the DataPhase */
172 u8 buf[RT5677_SPI_HEADER + RT5677_SPI_BURST_LEN + 1];
173 u8 *body = buf + RT5677_SPI_HEADER;
175 const u8 *cb = txbuf;
181 dev_err(&g_spi->dev, "Bad write align 0x%x(%zu)\n", addr, len);
186 len_with_pad = len + 1;
188 memset(&t, 0, sizeof(t));
190 t.speed_hz = RT5677_SPI_FREQ;
191 spi_message_init_with_transfers(&m, &t, 1);
193 for (offset = 0; offset < len_with_pad;) {
194 spi_cmd = rt5677_spi_select_cmd(false, (addr + offset) & 7,
195 len_with_pad - offset, &t.len);
197 /* Construct SPI message header */
199 buf[1] = ((addr + offset) & 0xff000000) >> 24;
200 buf[2] = ((addr + offset) & 0x00ff0000) >> 16;
201 buf[3] = ((addr + offset) & 0x0000ff00) >> 8;
202 buf[4] = ((addr + offset) & 0x000000ff) >> 0;
204 /* Fetch data from caller buffer */
205 rt5677_spi_reverse(body, t.len, cb + offset, len - offset);
207 t.len += RT5677_SPI_HEADER + 1;
209 mutex_lock(&spi_mutex);
210 status |= spi_sync(g_spi, &m);
211 mutex_unlock(&spi_mutex);
215 EXPORT_SYMBOL_GPL(rt5677_spi_write);
217 int rt5677_spi_write_firmware(u32 addr, const struct firmware *fw)
219 return rt5677_spi_write(addr, fw->data, fw->size);
221 EXPORT_SYMBOL_GPL(rt5677_spi_write_firmware);
223 static int rt5677_spi_probe(struct spi_device *spi)
229 static struct spi_driver rt5677_spi_driver = {
233 .probe = rt5677_spi_probe,
235 module_spi_driver(rt5677_spi_driver);
237 MODULE_DESCRIPTION("ASoC RT5677 SPI driver");
238 MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>");
239 MODULE_LICENSE("GPL v2");