2019-06-04 08:11:33 +00:00
|
|
|
// SPDX-License-Identifier: GPL-2.0-only
|
2011-02-14 02:20:39 +00:00
|
|
|
/*
|
|
|
|
* OpenCores tiny SPI master driver
|
|
|
|
*
|
2020-07-08 19:44:00 +00:00
|
|
|
* https://opencores.org/project,tiny_spi
|
2011-02-14 02:20:39 +00:00
|
|
|
*
|
|
|
|
* 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>
|
|
|
|
*/
|
|
|
|
|
|
|
|
#include <linux/interrupt.h>
|
|
|
|
#include <linux/errno.h>
|
2011-07-03 19:44:29 +00:00
|
|
|
#include <linux/module.h>
|
2011-02-14 02:20:39 +00:00
|
|
|
#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/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;
|
|
|
|
};
|
|
|
|
|
|
|
|
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 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) {
|
2012-07-30 14:16:14 +00:00
|
|
|
/* use interrupt driven data transfer */
|
2011-02-14 02:20:39 +00:00
|
|
|
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 {
|
2014-01-08 08:00:04 +00:00
|
|
|
/* we need to tighten the transfer loop */
|
|
|
|
writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA);
|
|
|
|
for (i = 1; i < t->len; i++) {
|
|
|
|
writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA);
|
|
|
|
|
|
|
|
if (rxp || (i != t->len - 1))
|
2011-02-14 02:20:39 +00:00
|
|
|
tiny_spi_wait_txr(hw);
|
2014-01-08 08:00:04 +00:00
|
|
|
if (rxp)
|
|
|
|
*rxp++ = readb(hw->base + TINY_SPI_TXDATA);
|
2011-02-14 02:20:39 +00:00
|
|
|
}
|
|
|
|
tiny_spi_wait_txe(hw);
|
2014-01-08 08:00:04 +00:00
|
|
|
if (rxp)
|
|
|
|
*rxp++ = readb(hw->base + TINY_SPI_RXDATA);
|
2011-02-14 02:20:39 +00:00
|
|
|
}
|
2014-01-08 08:00:04 +00:00
|
|
|
|
2011-02-14 02:20:39 +00:00
|
|
|
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>
|
|
|
|
|
2012-12-07 16:57:14 +00:00
|
|
|
static int tiny_spi_of_probe(struct platform_device *pdev)
|
2011-02-14 02:20:39 +00:00
|
|
|
{
|
|
|
|
struct tiny_spi *hw = platform_get_drvdata(pdev);
|
|
|
|
struct device_node *np = pdev->dev.of_node;
|
2015-09-09 11:55:53 +00:00
|
|
|
u32 val;
|
2011-02-14 02:20:39 +00:00
|
|
|
|
|
|
|
if (!np)
|
|
|
|
return 0;
|
|
|
|
hw->bitbang.master->dev.of_node = pdev->dev.of_node;
|
2015-09-09 11:55:53 +00:00
|
|
|
if (!of_property_read_u32(np, "clock-frequency", &val))
|
|
|
|
hw->freq = val;
|
|
|
|
if (!of_property_read_u32(np, "baud-width", &val))
|
|
|
|
hw->baudwidth = val;
|
2011-02-14 02:20:39 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
#else /* !CONFIG_OF */
|
2012-12-07 16:57:14 +00:00
|
|
|
static int tiny_spi_of_probe(struct platform_device *pdev)
|
2011-02-14 02:20:39 +00:00
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
#endif /* CONFIG_OF */
|
|
|
|
|
2012-12-07 16:57:14 +00:00
|
|
|
static int tiny_spi_probe(struct platform_device *pdev)
|
2011-02-14 02:20:39 +00:00
|
|
|
{
|
2013-07-30 07:58:59 +00:00
|
|
|
struct tiny_spi_platform_data *platp = dev_get_platdata(&pdev->dev);
|
2011-02-14 02:20:39 +00:00
|
|
|
struct tiny_spi *hw;
|
|
|
|
struct spi_master *master;
|
|
|
|
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->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
|
|
|
|
master->setup = tiny_spi_setup;
|
2019-12-05 09:24:11 +00:00
|
|
|
master->use_gpio_descriptors = true;
|
2011-02-14 02:20:39 +00:00
|
|
|
|
|
|
|
hw = spi_master_get_devdata(master);
|
|
|
|
platform_set_drvdata(pdev, hw);
|
|
|
|
|
|
|
|
/* setup the state for the bitbang driver */
|
2013-09-10 07:43:41 +00:00
|
|
|
hw->bitbang.master = master;
|
2011-02-14 02:20:39 +00:00
|
|
|
hw->bitbang.setup_transfer = tiny_spi_setup_transfer;
|
|
|
|
hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs;
|
|
|
|
|
|
|
|
/* find and map our resources */
|
2019-09-04 13:59:03 +00:00
|
|
|
hw->base = devm_platform_ioremap_resource(pdev, 0);
|
2013-08-24 17:13:15 +00:00
|
|
|
if (IS_ERR(hw->base)) {
|
|
|
|
err = PTR_ERR(hw->base);
|
|
|
|
goto exit;
|
|
|
|
}
|
2011-02-14 02:20:39 +00:00
|
|
|
/* 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->freq = platp->freq;
|
|
|
|
hw->baudwidth = platp->baudwidth;
|
|
|
|
} else {
|
|
|
|
err = tiny_spi_of_probe(pdev);
|
|
|
|
if (err)
|
|
|
|
goto exit;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* 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:
|
|
|
|
spi_master_put(master);
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
2012-12-07 16:57:14 +00:00
|
|
|
static int tiny_spi_remove(struct platform_device *pdev)
|
2011-02-14 02:20:39 +00:00
|
|
|
{
|
|
|
|
struct tiny_spi *hw = platform_get_drvdata(pdev);
|
|
|
|
struct spi_master *master = hw->bitbang.master;
|
|
|
|
|
|
|
|
spi_bitbang_stop(&hw->bitbang);
|
|
|
|
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);
|
|
|
|
#endif /* CONFIG_OF */
|
|
|
|
|
|
|
|
static struct platform_driver tiny_spi_driver = {
|
|
|
|
.probe = tiny_spi_probe,
|
2012-12-07 16:57:14 +00:00
|
|
|
.remove = tiny_spi_remove,
|
2011-02-14 02:20:39 +00:00
|
|
|
.driver = {
|
|
|
|
.name = DRV_NAME,
|
|
|
|
.pm = NULL,
|
2013-03-14 10:01:50 +00:00
|
|
|
.of_match_table = of_match_ptr(tiny_spi_match),
|
2011-02-14 02:20:39 +00:00
|
|
|
},
|
|
|
|
};
|
2011-10-05 17:29:49 +00:00
|
|
|
module_platform_driver(tiny_spi_driver);
|
2011-02-14 02:20:39 +00:00
|
|
|
|
|
|
|
MODULE_DESCRIPTION("OpenCores tiny SPI driver");
|
|
|
|
MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
|
|
|
|
MODULE_LICENSE("GPL");
|
|
|
|
MODULE_ALIAS("platform:" DRV_NAME);
|