1 /* 2 * rt5677-spi.c -- RT5677 ALSA SoC audio codec driver 3 * 4 * Copyright 2013 Realtek Semiconductor Corp. 5 * Author: Oder Chiou <oder_chiou@realtek.com> 6 * 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. 10 */ 11 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/gpio.h> 22 #include <linux/sched.h> 23 #include <linux/kthread.h> 24 #include <linux/uaccess.h> 25 #include <linux/miscdevice.h> 26 #include <linux/regulator/consumer.h> 27 #include <linux/pm_qos.h> 28 #include <linux/sysfs.h> 29 #include <linux/clk.h> 30 #include <linux/firmware.h> 31 32 #include "rt5677-spi.h" 33 34 #define RT5677_SPI_BURST_LEN 240 35 #define RT5677_SPI_HEADER 5 36 #define RT5677_SPI_FREQ 6000000 37 38 /* The AddressPhase and DataPhase of SPI commands are MSB first on the wire. 39 * DataPhase word size of 16-bit commands is 2 bytes. 40 * DataPhase word size of 32-bit commands is 4 bytes. 41 * DataPhase word size of burst commands is 8 bytes. 42 * The DSP CPU is little-endian. 43 */ 44 #define RT5677_SPI_WRITE_BURST 0x5 45 #define RT5677_SPI_READ_BURST 0x4 46 #define RT5677_SPI_WRITE_32 0x3 47 #define RT5677_SPI_READ_32 0x2 48 #define RT5677_SPI_WRITE_16 0x1 49 #define RT5677_SPI_READ_16 0x0 50 51 static struct spi_device *g_spi; 52 static DEFINE_MUTEX(spi_mutex); 53 54 /* Select a suitable transfer command for the next transfer to ensure 55 * the transfer address is always naturally aligned while minimizing 56 * the total number of transfers required. 57 * 58 * 3 transfer commands are available: 59 * RT5677_SPI_READ/WRITE_16: Transfer 2 bytes 60 * RT5677_SPI_READ/WRITE_32: Transfer 4 bytes 61 * RT5677_SPI_READ/WRITE_BURST: Transfer any multiples of 8 bytes 62 * 63 * For example, reading 260 bytes at 0x60030002 uses the following commands: 64 * 0x60030002 RT5677_SPI_READ_16 2 bytes 65 * 0x60030004 RT5677_SPI_READ_32 4 bytes 66 * 0x60030008 RT5677_SPI_READ_BURST 240 bytes 67 * 0x600300F8 RT5677_SPI_READ_BURST 8 bytes 68 * 0x60030100 RT5677_SPI_READ_32 4 bytes 69 * 0x60030104 RT5677_SPI_READ_16 2 bytes 70 * 71 * Input: 72 * @read: true for read commands; false for write commands 73 * @align: alignment of the next transfer address 74 * @remain: number of bytes remaining to transfer 75 * 76 * Output: 77 * @len: number of bytes to transfer with the selected command 78 * Returns the selected command 79 */ 80 static u8 rt5677_spi_select_cmd(bool read, u32 align, u32 remain, u32 *len) 81 { 82 u8 cmd; 83 84 if (align == 2 || align == 6 || remain == 2) { 85 cmd = RT5677_SPI_READ_16; 86 *len = 2; 87 } else if (align == 4 || remain <= 6) { 88 cmd = RT5677_SPI_READ_32; 89 *len = 4; 90 } else { 91 cmd = RT5677_SPI_READ_BURST; 92 *len = min_t(u32, remain & ~7, RT5677_SPI_BURST_LEN); 93 } 94 return read ? cmd : cmd + 1; 95 } 96 97 /* Copy dstlen bytes from src to dst, while reversing byte order for each word. 98 * If srclen < dstlen, zeros are padded. 99 */ 100 static void rt5677_spi_reverse(u8 *dst, u32 dstlen, const u8 *src, u32 srclen) 101 { 102 u32 w, i, si; 103 u32 word_size = min_t(u32, dstlen, 8); 104 105 for (w = 0; w < dstlen; w += word_size) { 106 for (i = 0; i < word_size; i++) { 107 si = w + word_size - i - 1; 108 dst[w + i] = si < srclen ? src[si] : 0; 109 } 110 } 111 } 112 113 /* Read DSP address space using SPI. addr and len have to be 2-byte aligned. */ 114 int rt5677_spi_read(u32 addr, void *rxbuf, size_t len) 115 { 116 u32 offset; 117 int status = 0; 118 struct spi_transfer t[2]; 119 struct spi_message m; 120 /* +4 bytes is for the DummyPhase following the AddressPhase */ 121 u8 header[RT5677_SPI_HEADER + 4]; 122 u8 body[RT5677_SPI_BURST_LEN]; 123 u8 spi_cmd; 124 u8 *cb = rxbuf; 125 126 if (!g_spi) 127 return -ENODEV; 128 129 if ((addr & 1) || (len & 1)) { 130 dev_err(&g_spi->dev, "Bad read align 0x%x(%zu)\n", addr, len); 131 return -EACCES; 132 } 133 134 memset(t, 0, sizeof(t)); 135 t[0].tx_buf = header; 136 t[0].len = sizeof(header); 137 t[0].speed_hz = RT5677_SPI_FREQ; 138 t[1].rx_buf = body; 139 t[1].speed_hz = RT5677_SPI_FREQ; 140 spi_message_init_with_transfers(&m, t, ARRAY_SIZE(t)); 141 142 for (offset = 0; offset < len; offset += t[1].len) { 143 spi_cmd = rt5677_spi_select_cmd(true, (addr + offset) & 7, 144 len - offset, &t[1].len); 145 146 /* Construct SPI message header */ 147 header[0] = spi_cmd; 148 header[1] = ((addr + offset) & 0xff000000) >> 24; 149 header[2] = ((addr + offset) & 0x00ff0000) >> 16; 150 header[3] = ((addr + offset) & 0x0000ff00) >> 8; 151 header[4] = ((addr + offset) & 0x000000ff) >> 0; 152 153 mutex_lock(&spi_mutex); 154 status |= spi_sync(g_spi, &m); 155 mutex_unlock(&spi_mutex); 156 157 /* Copy data back to caller buffer */ 158 rt5677_spi_reverse(cb + offset, t[1].len, body, t[1].len); 159 } 160 return status; 161 } 162 EXPORT_SYMBOL_GPL(rt5677_spi_read); 163 164 /* Write DSP address space using SPI. addr has to be 2-byte aligned. 165 * If len is not 2-byte aligned, an extra byte of zero is written at the end 166 * as padding. 167 */ 168 int rt5677_spi_write(u32 addr, const void *txbuf, size_t len) 169 { 170 u32 offset, len_with_pad = len; 171 int status = 0; 172 struct spi_transfer t; 173 struct spi_message m; 174 /* +1 byte is for the DummyPhase following the DataPhase */ 175 u8 buf[RT5677_SPI_HEADER + RT5677_SPI_BURST_LEN + 1]; 176 u8 *body = buf + RT5677_SPI_HEADER; 177 u8 spi_cmd; 178 const u8 *cb = txbuf; 179 180 if (!g_spi) 181 return -ENODEV; 182 183 if (addr & 1) { 184 dev_err(&g_spi->dev, "Bad write align 0x%x(%zu)\n", addr, len); 185 return -EACCES; 186 } 187 188 if (len & 1) 189 len_with_pad = len + 1; 190 191 memset(&t, 0, sizeof(t)); 192 t.tx_buf = buf; 193 t.speed_hz = RT5677_SPI_FREQ; 194 spi_message_init_with_transfers(&m, &t, 1); 195 196 for (offset = 0; offset < len_with_pad;) { 197 spi_cmd = rt5677_spi_select_cmd(false, (addr + offset) & 7, 198 len_with_pad - offset, &t.len); 199 200 /* Construct SPI message header */ 201 buf[0] = spi_cmd; 202 buf[1] = ((addr + offset) & 0xff000000) >> 24; 203 buf[2] = ((addr + offset) & 0x00ff0000) >> 16; 204 buf[3] = ((addr + offset) & 0x0000ff00) >> 8; 205 buf[4] = ((addr + offset) & 0x000000ff) >> 0; 206 207 /* Fetch data from caller buffer */ 208 rt5677_spi_reverse(body, t.len, cb + offset, len - offset); 209 offset += t.len; 210 t.len += RT5677_SPI_HEADER + 1; 211 212 mutex_lock(&spi_mutex); 213 status |= spi_sync(g_spi, &m); 214 mutex_unlock(&spi_mutex); 215 } 216 return status; 217 } 218 EXPORT_SYMBOL_GPL(rt5677_spi_write); 219 220 int rt5677_spi_write_firmware(u32 addr, const struct firmware *fw) 221 { 222 return rt5677_spi_write(addr, fw->data, fw->size); 223 } 224 EXPORT_SYMBOL_GPL(rt5677_spi_write_firmware); 225 226 static int rt5677_spi_probe(struct spi_device *spi) 227 { 228 g_spi = spi; 229 return 0; 230 } 231 232 static struct spi_driver rt5677_spi_driver = { 233 .driver = { 234 .name = "rt5677", 235 }, 236 .probe = rt5677_spi_probe, 237 }; 238 module_spi_driver(rt5677_spi_driver); 239 240 MODULE_DESCRIPTION("ASoC RT5677 SPI driver"); 241 MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>"); 242 MODULE_LICENSE("GPL v2"); 243