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/*
* OMAP7xx SPI 100k controller driver
* Author: Fabrice Crohas <fcrohas@gmail.com>
* from original omap1_mcspi driver
*
* Copyright (C) 2005, 2006 Nokia Corporation
* Author: Samuel Ortiz <samuel.ortiz@nokia.com> and
* Juha Yrj�l� <juha.yrjola@nokia.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#define OMAP1_SPI100K_MAX_FREQ 48000000
#define ICR_SPITAS (OMAP7XX_ICR_BASE + 0x12)
#define SPI_SETUP1 0x00
#define SPI_SETUP2 0x02
#define SPI_CTRL 0x04
#define SPI_STATUS 0x06
#define SPI_TX_LSB 0x08
#define SPI_TX_MSB 0x0a
#define SPI_RX_LSB 0x0c
#define SPI_RX_MSB 0x0e
#define SPI_SETUP1_INT_READ_ENABLE (1UL << 5)
#define SPI_SETUP1_INT_WRITE_ENABLE (1UL << 4)
#define SPI_SETUP1_CLOCK_DIVISOR(x) ((x) << 1)
#define SPI_SETUP1_CLOCK_ENABLE (1UL << 0)
#define SPI_SETUP2_ACTIVE_EDGE_FALLING (0UL << 0)
#define SPI_SETUP2_ACTIVE_EDGE_RISING (1UL << 0)
#define SPI_SETUP2_NEGATIVE_LEVEL (0UL << 5)
#define SPI_SETUP2_POSITIVE_LEVEL (1UL << 5)
#define SPI_SETUP2_LEVEL_TRIGGER (0UL << 10)
#define SPI_SETUP2_EDGE_TRIGGER (1UL << 10)
#define SPI_CTRL_SEN(x) ((x) << 7)
#define SPI_CTRL_WORD_SIZE(x) (((x) - 1) << 2)
#define SPI_CTRL_WR (1UL << 1)
#define SPI_CTRL_RD (1UL << 0)
#define SPI_STATUS_WE (1UL << 1)
#define SPI_STATUS_RD (1UL << 0)
/* use PIO for small transfers, avoiding DMA setup/teardown overhead and
* cache operations; better heuristics consider wordsize and bitrate.
*/
#define DMA_MIN_BYTES 8
#define SPI_RUNNING 0
#define SPI_SHUTDOWN 1
struct omap1_spi100k {
struct clk *ick;
struct clk *fck;
/* Virtual base address of the controller */
void __iomem *base;
};
struct omap1_spi100k_cs {
void __iomem *base;
int word_len;
};
static void spi100k_enable_clock(struct spi_master *master)
{
unsigned int val;
struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
/* enable SPI */
val = readw(spi100k->base + SPI_SETUP1);
val |= SPI_SETUP1_CLOCK_ENABLE;
writew(val, spi100k->base + SPI_SETUP1);
}
static void spi100k_disable_clock(struct spi_master *master)
{
unsigned int val;
struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
/* disable SPI */
val = readw(spi100k->base + SPI_SETUP1);
val &= ~SPI_SETUP1_CLOCK_ENABLE;
writew(val, spi100k->base + SPI_SETUP1);
}
static void spi100k_write_data(struct spi_master *master, int len, int data)
{
struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
/* write 16-bit word, shifting 8-bit data if necessary */
if (len <= 8) {
data <<= 8;
len = 16;
}
spi100k_enable_clock(master);
writew(data , spi100k->base + SPI_TX_MSB);
writew(SPI_CTRL_SEN(0) |
SPI_CTRL_WORD_SIZE(len) |
SPI_CTRL_WR,
spi100k->base + SPI_CTRL);
/* Wait for bit ack send change */
while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_WE) != SPI_STATUS_WE)
;
udelay(1000);
spi100k_disable_clock(master);
}
static int spi100k_read_data(struct spi_master *master, int len)
{
int dataH, dataL;
struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
/* Always do at least 16 bits */
if (len <= 8)
len = 16;
spi100k_enable_clock(master);
writew(SPI_CTRL_SEN(0) |
SPI_CTRL_WORD_SIZE(len) |
SPI_CTRL_RD,
spi100k->base + SPI_CTRL);
while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_RD) != SPI_STATUS_RD)
;
udelay(1000);
dataL = readw(spi100k->base + SPI_RX_LSB);
dataH = readw(spi100k->base + SPI_RX_MSB);
spi100k_disable_clock(master);
return dataL;
}
static void spi100k_open(struct spi_master *master)
{
/* get control of SPI */
struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
writew(SPI_SETUP1_INT_READ_ENABLE |
SPI_SETUP1_INT_WRITE_ENABLE |
SPI_SETUP1_CLOCK_DIVISOR(0), spi100k->base + SPI_SETUP1);
/* configure clock and interrupts */
writew(SPI_SETUP2_ACTIVE_EDGE_FALLING |
SPI_SETUP2_NEGATIVE_LEVEL |
SPI_SETUP2_LEVEL_TRIGGER, spi100k->base + SPI_SETUP2);
}
static void omap1_spi100k_force_cs(struct omap1_spi100k *spi100k, int enable)
{
if (enable)
writew(0x05fc, spi100k->base + SPI_CTRL);
else
writew(0x05fd, spi100k->base + SPI_CTRL);
}
static unsigned
omap1_spi100k_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
{
struct omap1_spi100k_cs *cs = spi->controller_state;
unsigned int count, c;
int word_len;
count = xfer->len;
c = count;
word_len = cs->word_len;
if (word_len <= 8) {
u8 *rx;
const u8 *tx;
rx = xfer->rx_buf;
tx = xfer->tx_buf;
do {
c -= 1;
if (xfer->tx_buf != NULL)
spi100k_write_data(spi->master, word_len, *tx++);
if (xfer->rx_buf != NULL)
*rx++ = spi100k_read_data(spi->master, word_len);
} while (c);
} else if (word_len <= 16) {
u16 *rx;
const u16 *tx;
rx = xfer->rx_buf;
tx = xfer->tx_buf;
do {
c -= 2;
if (xfer->tx_buf != NULL)
spi100k_write_data(spi->master, word_len, *tx++);
if (xfer->rx_buf != NULL)
*rx++ = spi100k_read_data(spi->master, word_len);
} while (c);
} else if (word_len <= 32) {
u32 *rx;
const u32 *tx;
rx = xfer->rx_buf;
tx = xfer->tx_buf;
do {
c -= 4;
if (xfer->tx_buf != NULL)
spi100k_write_data(spi->master, word_len, *tx);
if (xfer->rx_buf != NULL)
*rx = spi100k_read_data(spi->master, word_len);
} while (c);
}
return count - c;
}
/* called only when no transfer is active to this device */
static int omap1_spi100k_setup_transfer(struct spi_device *spi,
struct spi_transfer *t)
{
struct omap1_spi100k *spi100k = spi_master_get_devdata(spi->master);
struct omap1_spi100k_cs *cs = spi->controller_state;
u8 word_len = spi->bits_per_word;
if (t != NULL && t->bits_per_word)
word_len = t->bits_per_word;
if (!word_len)
word_len = 8;
if (spi->bits_per_word > 32)
return -EINVAL;
cs->word_len = word_len;
/* SPI init before transfer */
writew(0x3e , spi100k->base + SPI_SETUP1);
writew(0x00 , spi100k->base + SPI_STATUS);
writew(0x3e , spi100k->base + SPI_CTRL);
return 0;
}
/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
static int omap1_spi100k_setup(struct spi_device *spi)
{
int ret;
struct omap1_spi100k *spi100k;
struct omap1_spi100k_cs *cs = spi->controller_state;
spi100k = spi_master_get_devdata(spi->master);
if (!cs) {
cs = devm_kzalloc(&spi->dev, sizeof(*cs), GFP_KERNEL);
if
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