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OpenCloudOS-Kernel/drivers/spi/spi-oc-tiny.c

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/*
* OpenCores tiny SPI master driver
*
* http://opencores.org/project,tiny_spi
*
* Copyright (C) 2011 Thomas Chou <thomas@wytron.com.tw>
*
* Based on spi_s3c24xx.c, which is:
* Copyright (c) 2006 Ben Dooks
* Copyright (c) 2006 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>
*
* 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/errno.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/spi/spi_oc_tiny.h>
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/of.h>
#define DRV_NAME "spi_oc_tiny"
#define TINY_SPI_RXDATA 0
#define TINY_SPI_TXDATA 4
#define TINY_SPI_STATUS 8
#define TINY_SPI_CONTROL 12
#define TINY_SPI_BAUD 16
#define TINY_SPI_STATUS_TXE 0x1
#define TINY_SPI_STATUS_TXR 0x2
struct tiny_spi {
/* bitbang has to be first */
struct spi_bitbang bitbang;
struct completion done;
void __iomem *base;
int irq;
unsigned int freq;
unsigned int baudwidth;
unsigned int baud;
unsigned int speed_hz;
unsigned int mode;
unsigned int len;
unsigned int txc, rxc;
const u8 *txp;
u8 *rxp;
int gpio_cs_count;
int *gpio_cs;
};
static inline struct tiny_spi *tiny_spi_to_hw(struct spi_device *sdev)
{
return spi_master_get_devdata(sdev->master);
}
static unsigned int tiny_spi_baud(struct spi_device *spi, unsigned int hz)
{
struct tiny_spi *hw = tiny_spi_to_hw(spi);
return min(DIV_ROUND_UP(hw->freq, hz * 2), (1U << hw->baudwidth)) - 1;
}
static void tiny_spi_chipselect(struct spi_device *spi, int is_active)
{
struct tiny_spi *hw = tiny_spi_to_hw(spi);
if (hw->gpio_cs_count > 0) {
gpio_set_value(hw->gpio_cs[spi->chip_select],
(spi->mode & SPI_CS_HIGH) ? is_active : !is_active);
}
}
static int tiny_spi_setup_transfer(struct spi_device *spi,
struct spi_transfer *t)
{
struct tiny_spi *hw = tiny_spi_to_hw(spi);
unsigned int baud = hw->baud;
if (t) {
if (t->speed_hz && t->speed_hz != hw->speed_hz)
baud = tiny_spi_baud(spi, t->speed_hz);
}
writel(baud, hw->base + TINY_SPI_BAUD);
writel(hw->mode, hw->base + TINY_SPI_CONTROL);
return 0;
}
static int tiny_spi_setup(struct spi_device *spi)
{
struct tiny_spi *hw = tiny_spi_to_hw(spi);
if (spi->max_speed_hz != hw->speed_hz) {
hw->speed_hz = spi->max_speed_hz;
hw->baud = tiny_spi_baud(spi, hw->speed_hz);
}
hw->mode = spi->mode & (SPI_CPOL | SPI_CPHA);
return 0;
}
static inline void tiny_spi_wait_txr(struct tiny_spi *hw)
{
while (!(readb(hw->base + TINY_SPI_STATUS) &
TINY_SPI_STATUS_TXR))
cpu_relax();
}
static inline void tiny_spi_wait_txe(struct tiny_spi *hw)
{
while (!(readb(hw->base + TINY_SPI_STATUS) &
TINY_SPI_STATUS_TXE))
cpu_relax();
}
static int tiny_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
{
struct tiny_spi *hw = tiny_spi_to_hw(spi);
const u8 *txp = t->tx_buf;
u8 *rxp = t->rx_buf;
unsigned int i;
if (hw->irq >= 0) {
/* use interrupt driven data transfer */
hw->len = t->len;
hw->txp = t->tx_buf;
hw->rxp = t->rx_buf;
hw->txc = 0;
hw->rxc = 0;
/* send the first byte */
if (t->len > 1) {
writeb(hw->txp ? *hw->txp++ : 0,
hw->base + TINY_SPI_TXDATA);
hw->txc++;
writeb(hw->txp ? *hw->txp++ : 0,
hw->base + TINY_SPI_TXDATA);
hw->txc++;
writeb(TINY_SPI_STATUS_TXR, hw->base + TINY_SPI_STATUS);
} else {
writeb(hw->txp ? *hw->txp++ : 0,
hw->base + TINY_SPI_TXDATA);
hw->txc++;
writeb(TINY_SPI_STATUS_TXE, hw->base + TINY_SPI_STATUS);
}
wait_for_completion(&hw->done);
} else if (txp && rxp) {
/* we need to tighten the transfer loop */
writeb(*txp++, hw->base + TINY_SPI_TXDATA);
if (t->len > 1) {
writeb(*txp++, hw->base + TINY_SPI_TXDATA);
for (i = 2; i < t->len; i++) {
u8 rx, tx = *txp++;
tiny_spi_wait_txr(hw);
rx = readb(hw->base + TINY_SPI_TXDATA);
writeb(tx, hw->base + TINY_SPI_TXDATA);
*rxp++ = rx;
}
tiny_spi_wait_txr(hw);
*rxp++ = readb(hw->base + TINY_SPI_TXDATA);
}
tiny_spi_wait_txe(hw);
*rxp++ = readb(hw->base + TINY_SPI_RXDATA);
} else if (rxp) {
writeb(0, hw->base + TINY_SPI_TXDATA);
if (t->len > 1) {
writeb(0,
hw->base + TINY_SPI_TXDATA);
for (i = 2; i < t->len; i++) {
u8 rx;
tiny_spi_wait_txr(hw);
rx = readb(hw->base + TINY_SPI_TXDATA);
writeb(0, hw->base + TINY_SPI_TXDATA);
*rxp++ = rx;
}
tiny_spi_wait_txr(hw);
*rxp++ = readb(hw->base + TINY_SPI_TXDATA);
}
tiny_spi_wait_txe(hw);
*rxp++ = readb(hw->base + TINY_SPI_RXDATA);
} else if (txp) {
writeb(*txp++, hw->base + TINY_SPI_TXDATA);
if (t->len > 1) {
writeb(*txp++, hw->base + TINY_SPI_TXDATA);
for (i = 2; i < t->len; i++) {
u8 tx = *txp++;
tiny_spi_wait_txr(hw);
writeb(tx, hw->base + TINY_SPI_TXDATA);
}
}
tiny_spi_wait_txe(hw);
} else {
writeb(0, hw->base + TINY_SPI_TXDATA);
if (t->len > 1) {
writeb(0, hw->base + TINY_SPI_TXDATA);
for (i = 2; i < t->len; i++) {
tiny_spi_wait_txr(hw);
writeb(0, hw->base + TINY_SPI_TXDATA);
}
}
tiny_spi_wait_txe(hw);
}
return t->len;
}
static irqreturn_t tiny_spi_irq(int irq, void *dev)
{
struct tiny_spi *hw = dev;
writeb(0, hw->base + TINY_SPI_STATUS);
if (hw->rxc + 1 == hw->len) {
if (hw->rxp)
*hw->rxp++ = readb(hw->base + TINY_SPI_RXDATA);
hw->rxc++;
complete(&hw->done);
} else {
if (hw->rxp)
*hw->rxp++ = readb(hw->base + TINY_SPI_TXDATA);
hw->rxc++;
if (hw->txc < hw->len) {
writeb(hw->txp ? *hw->txp++ : 0,
hw->base + TINY_SPI_TXDATA);
hw->txc++;
writeb(TINY_SPI_STATUS_TXR,
hw->base + TINY_SPI_STATUS);
} else {
writeb(TINY_SPI_STATUS_TXE,
hw->base + TINY_SPI_STATUS);
}
}
return IRQ_HANDLED;
}
#ifdef CONFIG_OF
#include <linux/of_gpio.h>
static int tiny_spi_of_probe(struct platform_device *pdev)
{
struct tiny_spi *hw = platform_get_drvdata(pdev);
struct device_node *np = pdev->dev.of_node;
unsigned int i;
const __be32 *val;
int len;
if (!np)
return 0;
hw->gpio_cs_count = of_gpio_count(np);
if (hw->gpio_cs_count > 0) {
hw->gpio_cs = devm_kzalloc(&pdev->dev,
hw->gpio_cs_count * sizeof(unsigned int),
GFP_KERNEL);
if (!hw->gpio_cs)
return -ENOMEM;
}
for (i = 0; i < hw->gpio_cs_count; i++) {
hw->gpio_cs[i] = of_get_gpio_flags(np, i, NULL);
if (hw->gpio_cs[i] < 0)
return -ENODEV;
}
hw->bitbang.master->dev.of_node = pdev->dev.of_node;
val = of_get_property(pdev->dev.of_node,
"clock-frequency", &len);
if (val && len >= sizeof(__be32))
hw->freq = be32_to_cpup(val);
val = of_get_property(pdev->dev.of_node, "baud-width", &len);
if (val && len >= sizeof(__be32))
hw->baudwidth = be32_to_cpup(val);
return 0;
}
#else /* !CONFIG_OF */
static int tiny_spi_of_probe(struct platform_device *pdev)
{
return 0;
}
#endif /* CONFIG_OF */
static int tiny_spi_probe(struct platform_device *pdev)
{
struct tiny_spi_platform_data *platp = pdev->dev.platform_data;
struct tiny_spi *hw;
struct spi_master *master;
struct resource *res;
unsigned int i;
int err = -ENODEV;
master = spi_alloc_master(&pdev->dev, sizeof(struct tiny_spi));
if (!master)
return err;
/* setup the master state. */
master->bus_num = pdev->id;
master->num_chipselect = 255;
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
master->setup = tiny_spi_setup;
hw = spi_master_get_devdata(master);
platform_set_drvdata(pdev, hw);
/* setup the state for the bitbang driver */
hw->bitbang.master = spi_master_get(master);
if (!hw->bitbang.master)
return err;
hw->bitbang.setup_transfer = tiny_spi_setup_transfer;
hw->bitbang.chipselect = tiny_spi_chipselect;
hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs;
/* find and map our resources */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
goto exit_busy;
if (!devm_request_mem_region(&pdev->dev, res->start, resource_size(res),
pdev->name))
goto exit_busy;
hw->base = devm_ioremap_nocache(&pdev->dev, res->start,
resource_size(res));
if (!hw->base)
goto exit_busy;
/* irq is optional */
hw->irq = platform_get_irq(pdev, 0);
if (hw->irq >= 0) {
init_completion(&hw->done);
err = devm_request_irq(&pdev->dev, hw->irq, tiny_spi_irq, 0,
pdev->name, hw);
if (err)
goto exit;
}
/* find platform data */
if (platp) {
hw->gpio_cs_count = platp->gpio_cs_count;
hw->gpio_cs = platp->gpio_cs;
if (platp->gpio_cs_count && !platp->gpio_cs)
goto exit_busy;
hw->freq = platp->freq;
hw->baudwidth = platp->baudwidth;
} else {
err = tiny_spi_of_probe(pdev);
if (err)
goto exit;
}
for (i = 0; i < hw->gpio_cs_count; i++) {
err = gpio_request(hw->gpio_cs[i], dev_name(&pdev->dev));
if (err)
goto exit_gpio;
gpio_direction_output(hw->gpio_cs[i], 1);
}
hw->bitbang.master->num_chipselect = max(1, hw->gpio_cs_count);
/* register our spi controller */
err = spi_bitbang_start(&hw->bitbang);
if (err)
goto exit;
dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
return 0;
exit_gpio:
while (i-- > 0)
gpio_free(hw->gpio_cs[i]);
exit_busy:
err = -EBUSY;
exit:
platform_set_drvdata(pdev, NULL);
spi_master_put(master);
return err;
}
static int tiny_spi_remove(struct platform_device *pdev)
{
struct tiny_spi *hw = platform_get_drvdata(pdev);
struct spi_master *master = hw->bitbang.master;
unsigned int i;
spi_bitbang_stop(&hw->bitbang);
for (i = 0; i < hw->gpio_cs_count; i++)
gpio_free(hw->gpio_cs[i]);
platform_set_drvdata(pdev, NULL);
spi_master_put(master);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id tiny_spi_match[] = {
{ .compatible = "opencores,tiny-spi-rtlsvn2", },
{},
};
MODULE_DEVICE_TABLE(of, tiny_spi_match);
#else /* CONFIG_OF */
#define tiny_spi_match NULL
#endif /* CONFIG_OF */
static struct platform_driver tiny_spi_driver = {
.probe = tiny_spi_probe,
.remove = tiny_spi_remove,
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
.pm = NULL,
.of_match_table = tiny_spi_match,
},
};
module_platform_driver(tiny_spi_driver);
MODULE_DESCRIPTION("OpenCores tiny SPI driver");
MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);
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