/* * rt5677-spi.c -- RT5677 ALSA SoC audio codec driver * * Copyright 2013 Realtek Semiconductor Corp. * Author: Oder Chiou * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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 "); MODULE_LICENSE("GPL v2");