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/*
* drivers/spi/spi-fsl-dspi.c
*
* Copyright 2013 Freescale Semiconductor, Inc.
*
* Freescale DSPI driver
* This file contains a driver for the Freescale DSPI
*
* 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.
*
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/sched.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/time.h>
#define DRIVER_NAME "fsl-dspi"
#define TRAN_STATE_RX_VOID 0x01
#define TRAN_STATE_TX_VOID 0x02
#define TRAN_STATE_WORD_ODD_NUM 0x04
#define DSPI_FIFO_SIZE 4
#define SPI_MCR 0x00
#define SPI_MCR_MASTER (1 << 31)
#define SPI_MCR_PCSIS (0x3F << 16)
#define SPI_MCR_CLR_TXF (1 << 11)
#define SPI_MCR_CLR_RXF (1 << 10)
#define SPI_TCR 0x08
#define SPI_CTAR(x) (0x0c + (((x) & 0x3) * 4))
#define SPI_CTAR_FMSZ(x) (((x) & 0x0000000f) << 27)
#define SPI_CTAR_CPOL(x) ((x) << 26)
#define SPI_CTAR_CPHA(x) ((x) << 25)
#define SPI_CTAR_LSBFE(x) ((x) << 24)
#define SPI_CTAR_PCSSCK(x) (((x) & 0x00000003) << 22)
#define SPI_CTAR_PASC(x) (((x) & 0x00000003) << 20)
#define SPI_CTAR_PDT(x) (((x) & 0x00000003) << 18)
#define SPI_CTAR_PBR(x) (((x) & 0x00000003) << 16)
#define SPI_CTAR_CSSCK(x) (((x) & 0x0000000f) << 12)
#define SPI_CTAR_ASC(x) (((x) & 0x0000000f) << 8)
#define SPI_CTAR_DT(x) (((x) & 0x0000000f) << 4)
#define SPI_CTAR_BR(x) ((x) & 0x0000000f)
#define SPI_CTAR_SCALE_BITS 0xf
#define SPI_CTAR0_SLAVE 0x0c
#define SPI_SR 0x2c
#define SPI_SR_EOQF 0x10000000
#define SPI_RSER 0x30
#define SPI_RSER_EOQFE 0x10000000
#define SPI_PUSHR 0x34
#define SPI_PUSHR_CONT (1 << 31)
#define SPI_PUSHR_CTAS(x) (((x) & 0x00000003) << 28)
#define SPI_PUSHR_EOQ (1 << 27)
#define SPI_PUSHR_CTCNT (1 << 26)
#define SPI_PUSHR_PCS(x) (((1 << x) & 0x0000003f) << 16)
#define SPI_PUSHR_TXDATA(x) ((x) & 0x0000ffff)
#define SPI_PUSHR_SLAVE 0x34
#define SPI_POPR 0x38
#define SPI_POPR_RXDATA(x) ((x) & 0x0000ffff)
#define SPI_TXFR0 0x3c
#define SPI_TXFR1 0x40
#define SPI_TXFR2 0x44
#define SPI_TXFR3 0x48
#define SPI_RXFR0 0x7c
#define SPI_RXFR1 0x80
#define SPI_RXFR2 0x84
#define SPI_RXFR3 0x88
#define SPI_FRAME_BITS(bits) SPI_CTAR_FMSZ((bits) - 1)
#define SPI_FRAME_BITS_MASK SPI_CTAR_FMSZ(0xf)
#define SPI_FRAME_BITS_16 SPI_CTAR_FMSZ(0xf)
#define SPI_FRAME_BITS_8 SPI_CTAR_FMSZ(0x7)
#define SPI_CS_INIT 0x01
#define SPI_CS_ASSERT 0x02
#define SPI_CS_DROP 0x04
struct chip_data {
u32 mcr_val;
u32 ctar_val;
u16 void_write_data;
};
struct fsl_dspi {
struct spi_master *master;
struct platform_device *pdev;
struct regmap *regmap;
int irq;
struct clk *clk;
struct spi_transfer *cur_transfer;
struct spi_message *cur_msg;
struct chip_data *cur_chip;
size_t len;
void *tx;
void *tx_end;
void *rx;
void *rx_end;
char dataflags;
u8 cs;
u16 void_write_data;
u32 cs_change;
wait_queue_head_t waitq;
u32 waitflags;
};
static inline int is_double_byte_mode(struct fsl_dspi *dspi)
{
unsigned int val;
regmap_read(dspi->regmap, SPI_CTAR(dspi->cs), &val);
return ((val & SPI_FRAME_BITS_MASK) == SPI_FRAME_BITS(8)) ? 0 : 1;
}
static void hz_to_spi_baud(char *pbr, char *br, int speed_hz,
unsigned long clkrate)
{
/* Valid baud rate pre-scaler values */
int pbr_tbl[4] = {2, 3, 5, 7};
int brs[16] = { 2, 4, 6, 8,
16, 32, 64, 128,
256, 512, 1024, 2048,
4096, 8192, 16384, 32768 };
int scale_needed, scale, minscale = INT_MAX;
int i, j;
scale_needed = clkrate / speed_hz;
if (clkrate % speed_hz)
scale_needed++;
for (i = 0; i < ARRAY_SIZE(brs); i++)
for (j = 0; j < ARRAY_SIZE(pbr_tbl); j++) {
scale = brs[i] * pbr_tbl[j];
if (scale >= scale_needed) {
if (scale < minscale) {
minscale = scale;
*br = i;
*pbr = j;
}
break;
}
}
if (minscale == INT_MAX) {
pr_warn("Can not find valid baud rate,speed_hz is %d,clkrate is %ld, we use the max prescaler value.\n",
speed_hz, clkrate);
*pbr = ARRAY_SIZE(pbr_tbl) - 1;
*br = ARRAY_SIZE(brs) - 1;
}
}
static void ns_delay_scale(char *psc, char *sc, int delay_ns,
unsigned long clkrate)
{
int pscale_tbl[4] = {1, 3, 5, 7};
int scale_needed, scale, minscale = INT_MAX;
int i, j;
u32 remainder;
scale_needed = div_u64_rem((u64)delay_ns * clkrate, NSEC_PER_SEC,
&remainder);
if (remainder)
scale_needed++;
for (i = 0; i < ARRAY_SIZE(pscale_tbl); i++)
for (j = 0; j <= SPI_CTAR_SCALE_BITS; j++) {
scale = pscale_tbl[i] * (2 << j);
if (scale >= scale_needed) {
if (scale < minscale) {
minscale = scale;
*psc = i;
*sc = j;
}
break;
}
}
if (minscale == INT_MAX) {
pr_warn("Cannot find correct scale values for %dns delay at clkrate %ld, using max prescaler value",
delay_ns, clkrate);
*psc = ARRAY_SIZE(pscale_tbl) - 1;
*sc = SPI_CTAR_SCALE_BITS;
}
}
static int dspi_transfer_write(struct fsl_dspi *dspi)
{
int tx_count = 0;
int tx_word;
u16 d16;
u8 d8;
u32 dspi_pushr = 0;
int first = 1;
tx_word = is_double_byte_mode(dspi);
/* If we are in word mode, but only have a single byte to transfer
* then switch to byte mode temporarily. Will switch back at the
* end of the transfer.
*/
if (tx_word && (dspi->len == 1)) {
dspi->dataflags |= TRAN_STATE_WORD_ODD_NUM;
regmap_update_bits(dspi->regmap, SPI_CTAR(dspi->cs),
SPI_FRAME_BITS_MASK, SPI_FRAME_BITS(8));
tx_word = 0;
}
while (dspi->len && (tx_count < DSPI_FIFO_SIZE)) {
if (tx_word) {
if (dspi->len == 1)
break;
if (!(dspi->dataflags & TRAN_STATE_TX_VOID)) {
d16 = *(u16 *)dspi->tx;
dspi->tx += 2;
} else {
d16 = dspi->void_write_data;
}
dspi_pushr = SPI_PUSHR_TXDATA(d16) |
SPI_PUSHR_PCS(dspi->cs) |
SPI_PUSHR_CTAS(dspi->cs) |
SPI_PUSHR_CONT;
dspi->len -= 2;
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