linux/drivers/spi/spi-orion.c

514 lines
11 KiB
C

/*
* Marvell Orion SPI controller driver
*
* Author: Shadi Ammouri <shadi@marvell.com>
* Copyright (C) 2007-2008 Marvell Ltd.
*
* 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 <linux/init.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/clk.h>
#include <linux/sizes.h>
#include <asm/unaligned.h>
#define DRIVER_NAME "orion_spi"
#define ORION_NUM_CHIPSELECTS 1 /* only one slave is supported*/
#define ORION_SPI_WAIT_RDY_MAX_LOOP 2000 /* in usec */
#define ORION_SPI_IF_CTRL_REG 0x00
#define ORION_SPI_IF_CONFIG_REG 0x04
#define ORION_SPI_DATA_OUT_REG 0x08
#define ORION_SPI_DATA_IN_REG 0x0c
#define ORION_SPI_INT_CAUSE_REG 0x10
#define ORION_SPI_MODE_CPOL (1 << 11)
#define ORION_SPI_MODE_CPHA (1 << 12)
#define ORION_SPI_IF_8_16_BIT_MODE (1 << 5)
#define ORION_SPI_CLK_PRESCALE_MASK 0x1F
#define ORION_SPI_MODE_MASK (ORION_SPI_MODE_CPOL | \
ORION_SPI_MODE_CPHA)
struct orion_spi {
struct spi_master *master;
void __iomem *base;
unsigned int max_speed;
unsigned int min_speed;
struct clk *clk;
};
static inline void __iomem *spi_reg(struct orion_spi *orion_spi, u32 reg)
{
return orion_spi->base + reg;
}
static inline void
orion_spi_setbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
{
void __iomem *reg_addr = spi_reg(orion_spi, reg);
u32 val;
val = readl(reg_addr);
val |= mask;
writel(val, reg_addr);
}
static inline void
orion_spi_clrbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
{
void __iomem *reg_addr = spi_reg(orion_spi, reg);
u32 val;
val = readl(reg_addr);
val &= ~mask;
writel(val, reg_addr);
}
static int orion_spi_set_transfer_size(struct orion_spi *orion_spi, int size)
{
if (size == 16) {
orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
ORION_SPI_IF_8_16_BIT_MODE);
} else if (size == 8) {
orion_spi_clrbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
ORION_SPI_IF_8_16_BIT_MODE);
} else {
pr_debug("Bad bits per word value %d (only 8 or 16 are "
"allowed).\n", size);
return -EINVAL;
}
return 0;
}
static int orion_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
{
u32 tclk_hz;
u32 rate;
u32 prescale;
u32 reg;
struct orion_spi *orion_spi;
orion_spi = spi_master_get_devdata(spi->master);
tclk_hz = clk_get_rate(orion_spi->clk);
/*
* the supported rates are: 4,6,8...30
* round up as we look for equal or less speed
*/
rate = DIV_ROUND_UP(tclk_hz, speed);
rate = roundup(rate, 2);
/* check if requested speed is too small */
if (rate > 30)
return -EINVAL;
if (rate < 4)
rate = 4;
/* Convert the rate to SPI clock divisor value. */
prescale = 0x10 + rate/2;
reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
reg = ((reg & ~ORION_SPI_CLK_PRESCALE_MASK) | prescale);
writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
return 0;
}
static void
orion_spi_mode_set(struct spi_device *spi)
{
u32 reg;
struct orion_spi *orion_spi;
orion_spi = spi_master_get_devdata(spi->master);
reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
reg &= ~ORION_SPI_MODE_MASK;
if (spi->mode & SPI_CPOL)
reg |= ORION_SPI_MODE_CPOL;
if (spi->mode & SPI_CPHA)
reg |= ORION_SPI_MODE_CPHA;
writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
}
/*
* called only when no transfer is active on the bus
*/
static int
orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
{
struct orion_spi *orion_spi;
unsigned int speed = spi->max_speed_hz;
unsigned int bits_per_word = spi->bits_per_word;
int rc;
orion_spi = spi_master_get_devdata(spi->master);
if ((t != NULL) && t->speed_hz)
speed = t->speed_hz;
if ((t != NULL) && t->bits_per_word)
bits_per_word = t->bits_per_word;
orion_spi_mode_set(spi);
rc = orion_spi_baudrate_set(spi, speed);
if (rc)
return rc;
return orion_spi_set_transfer_size(orion_spi, bits_per_word);
}
static void orion_spi_set_cs(struct orion_spi *orion_spi, int enable)
{
if (enable)
orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
else
orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
}
static inline int orion_spi_wait_till_ready(struct orion_spi *orion_spi)
{
int i;
for (i = 0; i < ORION_SPI_WAIT_RDY_MAX_LOOP; i++) {
if (readl(spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG)))
return 1;
else
udelay(1);
}
return -1;
}
static inline int
orion_spi_write_read_8bit(struct spi_device *spi,
const u8 **tx_buf, u8 **rx_buf)
{
void __iomem *tx_reg, *rx_reg, *int_reg;
struct orion_spi *orion_spi;
orion_spi = spi_master_get_devdata(spi->master);
tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
/* clear the interrupt cause register */
writel(0x0, int_reg);
if (tx_buf && *tx_buf)
writel(*(*tx_buf)++, tx_reg);
else
writel(0, tx_reg);
if (orion_spi_wait_till_ready(orion_spi) < 0) {
dev_err(&spi->dev, "TXS timed out\n");
return -1;
}
if (rx_buf && *rx_buf)
*(*rx_buf)++ = readl(rx_reg);
return 1;
}
static inline int
orion_spi_write_read_16bit(struct spi_device *spi,
const u16 **tx_buf, u16 **rx_buf)
{
void __iomem *tx_reg, *rx_reg, *int_reg;
struct orion_spi *orion_spi;
orion_spi = spi_master_get_devdata(spi->master);
tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
/* clear the interrupt cause register */
writel(0x0, int_reg);
if (tx_buf && *tx_buf)
writel(__cpu_to_le16(get_unaligned((*tx_buf)++)), tx_reg);
else
writel(0, tx_reg);
if (orion_spi_wait_till_ready(orion_spi) < 0) {
dev_err(&spi->dev, "TXS timed out\n");
return -1;
}
if (rx_buf && *rx_buf)
put_unaligned(__le16_to_cpu(readl(rx_reg)), (*rx_buf)++);
return 1;
}
static unsigned int
orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
{
struct orion_spi *orion_spi;
unsigned int count;
int word_len;
orion_spi = spi_master_get_devdata(spi->master);
word_len = spi->bits_per_word;
count = xfer->len;
if (word_len == 8) {
const u8 *tx = xfer->tx_buf;
u8 *rx = xfer->rx_buf;
do {
if (orion_spi_write_read_8bit(spi, &tx, &rx) < 0)
goto out;
count--;
} while (count);
} else if (word_len == 16) {
const u16 *tx = xfer->tx_buf;
u16 *rx = xfer->rx_buf;
do {
if (orion_spi_write_read_16bit(spi, &tx, &rx) < 0)
goto out;
count -= 2;
} while (count);
}
out:
return xfer->len - count;
}
static int orion_spi_transfer_one_message(struct spi_master *master,
struct spi_message *m)
{
struct orion_spi *orion_spi = spi_master_get_devdata(master);
struct spi_device *spi = m->spi;
struct spi_transfer *t = NULL;
int par_override = 0;
int status = 0;
int cs_active = 0;
/* Load defaults */
status = orion_spi_setup_transfer(spi, NULL);
if (status < 0)
goto msg_done;
list_for_each_entry(t, &m->transfers, transfer_list) {
/* make sure buffer length is even when working in 16
* bit mode*/
if ((t->bits_per_word == 16) && (t->len & 1)) {
dev_err(&spi->dev,
"message rejected : "
"odd data length %d while in 16 bit mode\n",
t->len);
status = -EIO;
goto msg_done;
}
if (t->speed_hz && t->speed_hz < orion_spi->min_speed) {
dev_err(&spi->dev,
"message rejected : "
"device min speed (%d Hz) exceeds "
"required transfer speed (%d Hz)\n",
orion_spi->min_speed, t->speed_hz);
status = -EIO;
goto msg_done;
}
if (par_override || t->speed_hz || t->bits_per_word) {
par_override = 1;
status = orion_spi_setup_transfer(spi, t);
if (status < 0)
break;
if (!t->speed_hz && !t->bits_per_word)
par_override = 0;
}
if (!cs_active) {
orion_spi_set_cs(orion_spi, 1);
cs_active = 1;
}
if (t->len)
m->actual_length += orion_spi_write_read(spi, t);
if (t->delay_usecs)
udelay(t->delay_usecs);
if (t->cs_change) {
orion_spi_set_cs(orion_spi, 0);
cs_active = 0;
}
}
msg_done:
if (cs_active)
orion_spi_set_cs(orion_spi, 0);
m->status = status;
spi_finalize_current_message(master);
return 0;
}
static int orion_spi_reset(struct orion_spi *orion_spi)
{
/* Verify that the CS is deasserted */
orion_spi_set_cs(orion_spi, 0);
return 0;
}
static int orion_spi_setup(struct spi_device *spi)
{
struct orion_spi *orion_spi;
orion_spi = spi_master_get_devdata(spi->master);
if ((spi->max_speed_hz == 0)
|| (spi->max_speed_hz > orion_spi->max_speed))
spi->max_speed_hz = orion_spi->max_speed;
if (spi->max_speed_hz < orion_spi->min_speed) {
dev_err(&spi->dev, "setup: requested speed too low %d Hz\n",
spi->max_speed_hz);
return -EINVAL;
}
/*
* baudrate & width will be set orion_spi_setup_transfer
*/
return 0;
}
static int orion_spi_probe(struct platform_device *pdev)
{
struct spi_master *master;
struct orion_spi *spi;
struct resource *r;
unsigned long tclk_hz;
int status = 0;
const u32 *iprop;
int size;
master = spi_alloc_master(&pdev->dev, sizeof *spi);
if (master == NULL) {
dev_dbg(&pdev->dev, "master allocation failed\n");
return -ENOMEM;
}
if (pdev->id != -1)
master->bus_num = pdev->id;
if (pdev->dev.of_node) {
iprop = of_get_property(pdev->dev.of_node, "cell-index",
&size);
if (iprop && size == sizeof(*iprop))
master->bus_num = *iprop;
}
/* we support only mode 0, and no options */
master->mode_bits = SPI_CPHA | SPI_CPOL;
master->setup = orion_spi_setup;
master->transfer_one_message = orion_spi_transfer_one_message;
master->num_chipselect = ORION_NUM_CHIPSELECTS;
platform_set_drvdata(pdev, master);
spi = spi_master_get_devdata(master);
spi->master = master;
spi->clk = clk_get(&pdev->dev, NULL);
if (IS_ERR(spi->clk)) {
status = PTR_ERR(spi->clk);
goto out;
}
clk_prepare(spi->clk);
clk_enable(spi->clk);
tclk_hz = clk_get_rate(spi->clk);
spi->max_speed = DIV_ROUND_UP(tclk_hz, 4);
spi->min_speed = DIV_ROUND_UP(tclk_hz, 30);
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
spi->base = devm_ioremap_resource(&pdev->dev, r);
if (IS_ERR(spi->base)) {
status = PTR_ERR(spi->base);
goto out_rel_clk;
}
if (orion_spi_reset(spi) < 0)
goto out_rel_clk;
master->dev.of_node = pdev->dev.of_node;
status = spi_register_master(master);
if (status < 0)
goto out_rel_clk;
return status;
out_rel_clk:
clk_disable_unprepare(spi->clk);
clk_put(spi->clk);
out:
spi_master_put(master);
return status;
}
static int orion_spi_remove(struct platform_device *pdev)
{
struct spi_master *master;
struct orion_spi *spi;
master = platform_get_drvdata(pdev);
spi = spi_master_get_devdata(master);
clk_disable_unprepare(spi->clk);
clk_put(spi->clk);
spi_unregister_master(master);
return 0;
}
MODULE_ALIAS("platform:" DRIVER_NAME);
static const struct of_device_id orion_spi_of_match_table[] = {
{ .compatible = "marvell,orion-spi", },
{}
};
MODULE_DEVICE_TABLE(of, orion_spi_of_match_table);
static struct platform_driver orion_spi_driver = {
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(orion_spi_of_match_table),
},
.probe = orion_spi_probe,
.remove = orion_spi_remove,
};
module_platform_driver(orion_spi_driver);
MODULE_DESCRIPTION("Orion SPI driver");
MODULE_AUTHOR("Shadi Ammouri <shadi@marvell.com>");
MODULE_LICENSE("GPL");