mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
synced 2024-12-23 17:52:24 +02:00
d7185880b9
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@30669 3c298f89-4303-0410-b956-a3cf2f4a3e73
560 lines
12 KiB
C
560 lines
12 KiB
C
/*
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* ramips_spi.c -- Ralink RT288x/RT305x SPI controller driver
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*
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* Copyright (C) 2011 Sergiy <piratfm@gmail.com>
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* Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
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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/init.h>
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#include <linux/module.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/delay.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <linux/spi/spi.h>
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#define DRIVER_NAME "ramips-spi"
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#define RALINK_NUM_CHIPSELECTS 1 /* only one slave is supported*/
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#define RALINK_SPI_WAIT_RDY_MAX_LOOP 2000 /* in usec */
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#define RAMIPS_SPI_STAT 0x00
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#define RAMIPS_SPI_CFG 0x10
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#define RAMIPS_SPI_CTL 0x14
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#define RAMIPS_SPI_DATA 0x20
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/* SPISTAT register bit field */
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#define SPISTAT_BUSY BIT(0)
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/* SPICFG register bit field */
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#define SPICFG_LSBFIRST 0
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#define SPICFG_MSBFIRST BIT(8)
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#define SPICFG_SPICLKPOL BIT(6)
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#define SPICFG_RXCLKEDGE_FALLING BIT(5)
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#define SPICFG_TXCLKEDGE_FALLING BIT(4)
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#define SPICFG_SPICLK_PRESCALE_MASK 0x7
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#define SPICFG_SPICLK_DIV2 0
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#define SPICFG_SPICLK_DIV4 1
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#define SPICFG_SPICLK_DIV8 2
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#define SPICFG_SPICLK_DIV16 3
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#define SPICFG_SPICLK_DIV32 4
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#define SPICFG_SPICLK_DIV64 5
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#define SPICFG_SPICLK_DIV128 6
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#define SPICFG_SPICLK_DISABLE 7
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/* SPICTL register bit field */
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#define SPICTL_HIZSDO BIT(3)
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#define SPICTL_STARTWR BIT(2)
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#define SPICTL_STARTRD BIT(1)
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#define SPICTL_SPIENA BIT(0)
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#ifdef DEBUG
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#define spi_debug(args...) printk(args)
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#else
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#define spi_debug(args...)
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#endif
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struct ramips_spi {
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struct work_struct work;
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/* Lock access to transfer list.*/
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spinlock_t lock;
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struct list_head msg_queue;
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struct spi_master *master;
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void __iomem *base;
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unsigned int sys_freq;
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unsigned int speed;
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struct clk *clk;
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};
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static struct workqueue_struct *ramips_spi_wq;
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static inline struct ramips_spi *ramips_spidev_to_rs(struct spi_device *spi)
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{
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return spi_master_get_devdata(spi->master);
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}
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static inline u32 ramips_spi_read(struct ramips_spi *rs, u32 reg)
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{
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return ioread32(rs->base + reg);
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}
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static inline void ramips_spi_write(struct ramips_spi *rs, u32 reg, u32 val)
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{
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iowrite32(val, rs->base + reg);
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}
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static inline void ramips_spi_setbits(struct ramips_spi *rs, u32 reg, u32 mask)
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{
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void __iomem *addr = rs->base + reg;
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u32 val;
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val = ioread32(addr);
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val |= mask;
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iowrite32(val, addr);
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}
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static inline void ramips_spi_clrbits(struct ramips_spi *rs, u32 reg, u32 mask)
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{
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void __iomem *addr = rs->base + reg;
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u32 val;
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val = ioread32(addr);
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val &= ~mask;
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iowrite32(val, addr);
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}
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static int ramips_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
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{
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struct ramips_spi *rs = ramips_spidev_to_rs(spi);
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u32 rate;
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u32 prescale;
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u32 reg;
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spi_debug("%s: speed:%u\n", __func__, speed);
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/*
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* the supported rates are: 2,4,8...128
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* round up as we look for equal or less speed
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*/
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rate = DIV_ROUND_UP(rs->sys_freq, speed);
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spi_debug("%s: rate-1:%u\n", __func__, rate);
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rate = roundup_pow_of_two(rate);
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spi_debug("%s: rate-2:%u\n", __func__, rate);
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/* check if requested speed is too small */
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if (rate > 128)
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return -EINVAL;
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if (rate < 2)
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rate = 2;
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/* Convert the rate to SPI clock divisor value. */
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prescale = ilog2(rate/2);
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spi_debug("%s: prescale:%u\n", __func__, prescale);
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reg = ramips_spi_read(rs, RAMIPS_SPI_CFG);
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reg = ((reg & ~SPICFG_SPICLK_PRESCALE_MASK) | prescale);
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ramips_spi_write(rs, RAMIPS_SPI_CFG, reg);
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rs->speed = speed;
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return 0;
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}
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/*
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* called only when no transfer is active on the bus
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*/
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static int
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ramips_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
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{
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struct ramips_spi *rs = ramips_spidev_to_rs(spi);
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unsigned int speed = spi->max_speed_hz;
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int rc;
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unsigned int bits_per_word = 8;
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if ((t != NULL) && t->speed_hz)
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speed = t->speed_hz;
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if ((t != NULL) && t->bits_per_word)
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bits_per_word = t->bits_per_word;
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if (rs->speed != speed) {
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spi_debug("%s: speed_hz:%u\n", __func__, speed);
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rc = ramips_spi_baudrate_set(spi, speed);
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if (rc)
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return rc;
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}
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if (bits_per_word != 8) {
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spi_debug("%s: bad bits_per_word: %u\n", __func__,
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bits_per_word);
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return -EINVAL;
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}
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return 0;
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}
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static void ramips_spi_set_cs(struct ramips_spi *rs, int enable)
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{
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if (enable)
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ramips_spi_clrbits(rs, RAMIPS_SPI_CTL, SPICTL_SPIENA);
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else
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ramips_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_SPIENA);
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}
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static inline int ramips_spi_wait_till_ready(struct ramips_spi *rs)
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{
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int i;
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for (i = 0; i < RALINK_SPI_WAIT_RDY_MAX_LOOP; i++) {
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u32 status;
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status = ramips_spi_read(rs, RAMIPS_SPI_STAT);
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if ((status & SPISTAT_BUSY) == 0)
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return 0;
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udelay(1);
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}
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return -ETIMEDOUT;
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}
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static unsigned int
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ramips_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
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{
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struct ramips_spi *rs = ramips_spidev_to_rs(spi);
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unsigned count = 0;
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u8 *rx = xfer->rx_buf;
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const u8 *tx = xfer->tx_buf;
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int err;
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spi_debug("%s(%d): %s %s\n", __func__, xfer->len,
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(tx != NULL) ? "tx" : " ",
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(rx != NULL) ? "rx" : " ");
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if (tx) {
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for (count = 0; count < xfer->len; count++) {
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ramips_spi_write(rs, RAMIPS_SPI_DATA, tx[count]);
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ramips_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_STARTWR);
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err = ramips_spi_wait_till_ready(rs);
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if (err) {
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dev_err(&spi->dev, "TX failed, err=%d\n", err);
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goto out;
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}
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}
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}
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if (rx) {
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for (count = 0; count < xfer->len; count++) {
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ramips_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_STARTRD);
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err = ramips_spi_wait_till_ready(rs);
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if (err) {
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dev_err(&spi->dev, "RX failed, err=%d\n", err);
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goto out;
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}
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rx[count] = (u8) ramips_spi_read(rs, RAMIPS_SPI_DATA);
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}
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}
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out:
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return count;
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}
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static void ramips_spi_work(struct work_struct *work)
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{
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struct ramips_spi *rs =
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container_of(work, struct ramips_spi, work);
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spin_lock_irq(&rs->lock);
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while (!list_empty(&rs->msg_queue)) {
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struct spi_message *m;
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struct spi_device *spi;
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struct spi_transfer *t = NULL;
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int par_override = 0;
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int status = 0;
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int cs_active = 0;
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m = container_of(rs->msg_queue.next, struct spi_message,
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queue);
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list_del_init(&m->queue);
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spin_unlock_irq(&rs->lock);
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spi = m->spi;
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/* Load defaults */
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status = ramips_spi_setup_transfer(spi, NULL);
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if (status < 0)
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goto msg_done;
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list_for_each_entry(t, &m->transfers, transfer_list) {
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if (par_override || t->speed_hz || t->bits_per_word) {
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par_override = 1;
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status = ramips_spi_setup_transfer(spi, t);
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if (status < 0)
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break;
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if (!t->speed_hz && !t->bits_per_word)
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par_override = 0;
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}
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if (!cs_active) {
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ramips_spi_set_cs(rs, 1);
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cs_active = 1;
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}
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if (t->len)
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m->actual_length +=
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ramips_spi_write_read(spi, t);
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if (t->delay_usecs)
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udelay(t->delay_usecs);
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if (t->cs_change) {
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ramips_spi_set_cs(rs, 0);
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cs_active = 0;
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}
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}
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msg_done:
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if (cs_active)
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ramips_spi_set_cs(rs, 0);
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m->status = status;
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m->complete(m->context);
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spin_lock_irq(&rs->lock);
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}
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spin_unlock_irq(&rs->lock);
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}
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static int ramips_spi_setup(struct spi_device *spi)
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{
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struct ramips_spi *rs = ramips_spidev_to_rs(spi);
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if ((spi->max_speed_hz == 0) ||
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(spi->max_speed_hz > (rs->sys_freq / 2)))
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spi->max_speed_hz = (rs->sys_freq / 2);
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if (spi->max_speed_hz < (rs->sys_freq/128)) {
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dev_err(&spi->dev, "setup: requested speed too low %d Hz\n",
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spi->max_speed_hz);
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return -EINVAL;
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}
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if (spi->bits_per_word != 0 && spi->bits_per_word != 8) {
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dev_err(&spi->dev,
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"setup: requested bits per words - os wrong %d bpw\n",
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spi->bits_per_word);
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return -EINVAL;
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}
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if (spi->bits_per_word == 0)
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spi->bits_per_word = 8;
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/*
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* baudrate & width will be set ramips_spi_setup_transfer
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*/
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return 0;
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}
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static int ramips_spi_transfer(struct spi_device *spi, struct spi_message *m)
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{
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struct ramips_spi *rs;
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struct spi_transfer *t = NULL;
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unsigned long flags;
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m->actual_length = 0;
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m->status = 0;
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/* reject invalid messages and transfers */
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if (list_empty(&m->transfers) || !m->complete)
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return -EINVAL;
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rs = ramips_spidev_to_rs(spi);
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list_for_each_entry(t, &m->transfers, transfer_list) {
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unsigned int bits_per_word = spi->bits_per_word;
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if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
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dev_err(&spi->dev,
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"message rejected : "
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"invalid transfer data buffers\n");
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goto msg_rejected;
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}
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if (t->bits_per_word)
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bits_per_word = t->bits_per_word;
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if (bits_per_word != 8) {
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dev_err(&spi->dev,
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"message rejected : "
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"invalid transfer bits_per_word (%d bits)\n",
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bits_per_word);
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goto msg_rejected;
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}
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if (t->speed_hz && t->speed_hz < (rs->sys_freq/128)) {
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dev_err(&spi->dev,
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"message rejected : "
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"device min speed (%d Hz) exceeds "
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"required transfer speed (%d Hz)\n",
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(rs->sys_freq/128), t->speed_hz);
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goto msg_rejected;
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}
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}
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spin_lock_irqsave(&rs->lock, flags);
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list_add_tail(&m->queue, &rs->msg_queue);
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queue_work(ramips_spi_wq, &rs->work);
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spin_unlock_irqrestore(&rs->lock, flags);
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return 0;
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msg_rejected:
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/* Message rejected and not queued */
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m->status = -EINVAL;
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if (m->complete)
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m->complete(m->context);
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return -EINVAL;
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}
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static void __init ramips_spi_reset(struct ramips_spi *rs)
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{
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ramips_spi_write(rs, RAMIPS_SPI_CFG,
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SPICFG_MSBFIRST | SPICFG_TXCLKEDGE_FALLING |
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SPICFG_SPICLK_DIV16 | SPICFG_SPICLKPOL);
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ramips_spi_write(rs, RAMIPS_SPI_CTL, SPICTL_HIZSDO | SPICTL_SPIENA);
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}
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static int __init ramips_spi_probe(struct platform_device *pdev)
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{
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struct spi_master *master;
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struct ramips_spi *rs;
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struct resource *r;
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int status = 0;
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master = spi_alloc_master(&pdev->dev, sizeof(*rs));
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if (master == NULL) {
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dev_dbg(&pdev->dev, "master allocation failed\n");
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return -ENOMEM;
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}
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if (pdev->id != -1)
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master->bus_num = pdev->id;
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/* we support only mode 0, and no options */
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master->mode_bits = 0;
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master->setup = ramips_spi_setup;
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master->transfer = ramips_spi_transfer;
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master->num_chipselect = RALINK_NUM_CHIPSELECTS;
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dev_set_drvdata(&pdev->dev, master);
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rs = spi_master_get_devdata(master);
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rs->master = master;
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rs->clk = clk_get(NULL, "sys");
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if (IS_ERR(rs->clk)) {
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status = PTR_ERR(rs->clk);
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dev_err(&pdev->dev, "unable to get SYS clock, err=%d\n",
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status);
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goto out_put_master;
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}
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status = clk_enable(rs->clk);
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if (status)
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goto out_put_clk;
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rs->sys_freq = clk_get_rate(rs->clk);
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spi_debug("%s: sys_freq: %ld\n", __func__, rs->sys_freq);
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r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (r == NULL) {
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status = -ENODEV;
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goto out_disable_clk;
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}
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if (!request_mem_region(r->start, (r->end - r->start) + 1,
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dev_name(&pdev->dev))) {
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status = -EBUSY;
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goto out_disable_clk;
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}
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rs->base = ioremap(r->start, resource_size(r));
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if (rs->base == NULL) {
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dev_err(&pdev->dev, "ioremap failed\n");
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status = -ENOMEM;
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goto out_rel_mem;
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}
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INIT_WORK(&rs->work, ramips_spi_work);
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spin_lock_init(&rs->lock);
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INIT_LIST_HEAD(&rs->msg_queue);
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ramips_spi_reset(rs);
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status = spi_register_master(master);
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if (status)
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goto out_unmap_base;
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return 0;
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out_unmap_base:
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iounmap(rs->base);
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out_rel_mem:
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release_mem_region(r->start, (r->end - r->start) + 1);
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out_disable_clk:
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clk_disable(rs->clk);
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out_put_clk:
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clk_put(rs->clk);
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out_put_master:
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spi_master_put(master);
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return status;
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}
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static int __devexit ramips_spi_remove(struct platform_device *pdev)
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{
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struct spi_master *master;
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struct ramips_spi *rs;
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struct resource *r;
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master = dev_get_drvdata(&pdev->dev);
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rs = spi_master_get_devdata(master);
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cancel_work_sync(&rs->work);
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iounmap(rs->base);
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r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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release_mem_region(r->start, (r->end - r->start) + 1);
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clk_disable(rs->clk);
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clk_put(rs->clk);
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spi_unregister_master(master);
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|
|
return 0;
|
|
}
|
|
|
|
MODULE_ALIAS("platform:" DRIVER_NAME);
|
|
|
|
static struct platform_driver ramips_spi_driver = {
|
|
.driver = {
|
|
.name = DRIVER_NAME,
|
|
.owner = THIS_MODULE,
|
|
},
|
|
.remove = __devexit_p(ramips_spi_remove),
|
|
};
|
|
|
|
static int __init ramips_spi_init(void)
|
|
{
|
|
ramips_spi_wq = create_singlethread_workqueue(
|
|
ramips_spi_driver.driver.name);
|
|
if (ramips_spi_wq == NULL)
|
|
return -ENOMEM;
|
|
|
|
return platform_driver_probe(&ramips_spi_driver, ramips_spi_probe);
|
|
}
|
|
module_init(ramips_spi_init);
|
|
|
|
static void __exit ramips_spi_exit(void)
|
|
{
|
|
flush_workqueue(ramips_spi_wq);
|
|
platform_driver_unregister(&ramips_spi_driver);
|
|
|
|
destroy_workqueue(ramips_spi_wq);
|
|
}
|
|
module_exit(ramips_spi_exit);
|
|
|
|
MODULE_DESCRIPTION("Ralink SPI driver");
|
|
MODULE_AUTHOR("Sergiy <piratfm@gmail.com>");
|
|
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
|
|
MODULE_LICENSE("GPL");
|