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// SPDX-License-Identifier: GPL-2.0-only
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
#include <linux/spi/spi.h>
struct rtspi {
void __iomem *base;
};
/* SPI Flash Configuration Register */
#define RTL_SPI_SFCR 0x00
#define RTL_SPI_SFCR_RBO BIT(28)
#define RTL_SPI_SFCR_WBO BIT(27)
/* SPI Flash Control and Status Register */
#define RTL_SPI_SFCSR 0x08
#define RTL_SPI_SFCSR_CSB0 BIT(31)
#define RTL_SPI_SFCSR_CSB1 BIT(30)
#define RTL_SPI_SFCSR_RDY BIT(27)
#define RTL_SPI_SFCSR_CS BIT(24)
#define RTL_SPI_SFCSR_LEN_MASK ~(0x03 << 28)
#define RTL_SPI_SFCSR_LEN1 (0x00 << 28)
#define RTL_SPI_SFCSR_LEN4 (0x03 << 28)
/* SPI Flash Data Register */
#define RTL_SPI_SFDR 0x0c
#define REG(x) (rtspi->base + x)
static void rt_set_cs(struct spi_device *spi, bool active)
{
struct rtspi *rtspi = spi_controller_get_devdata(spi->controller);
u32 value;
/* CS0 bit is active low */
value = readl(REG(RTL_SPI_SFCSR));
if (active)
value |= RTL_SPI_SFCSR_CSB0;
else
value &= ~RTL_SPI_SFCSR_CSB0;
writel(value, REG(RTL_SPI_SFCSR));
}
static void set_size(struct rtspi *rtspi, int size)
{
u32 value;
value = readl(REG(RTL_SPI_SFCSR));
value &= RTL_SPI_SFCSR_LEN_MASK;
if (size == 4)
value |= RTL_SPI_SFCSR_LEN4;
else if (size == 1)
value |= RTL_SPI_SFCSR_LEN1;
writel(value, REG(RTL_SPI_SFCSR));
}
static inline void wait_ready(struct rtspi *rtspi)
{
while (!(readl(REG(RTL_SPI_SFCSR)) & RTL_SPI_SFCSR_RDY))
cpu_relax();
}
static void send4(struct rtspi *rtspi, const u32 *buf)
{
wait_ready(rtspi);
set_size(rtspi, 4);
writel(*buf, REG(RTL_SPI_SFDR));
}
static void send1(struct rtspi *rtspi, const u8 *buf)
{
wait_ready(rtspi);
set_size(rtspi, 1);
writel(buf[0] << 24, REG(RTL_SPI_SFDR));
}
static void rcv4(struct rtspi *rtspi, u32 *buf)
{
wait_ready(rtspi);
set_size(rtspi, 4);
*buf = readl(REG(RTL_SPI_SFDR));
}
static void rcv1(struct rtspi *rtspi, u8 *buf)
{
wait_ready(rtspi);
set_size(rtspi, 1);
*buf = readl(REG(RTL_SPI_SFDR)) >> 24;
}
static int transfer_one(struct spi_controller *ctrl, struct spi_device *spi,
struct spi_transfer *xfer)
{
struct rtspi *rtspi = spi_controller_get_devdata(ctrl);
void *rx_buf;
const void *tx_buf;
int cnt;
tx_buf = xfer->tx_buf;
rx_buf = xfer->rx_buf;
cnt = xfer->len;
if (tx_buf) {
while (cnt >= 4) {
send4(rtspi, tx_buf);
tx_buf += 4;
cnt -= 4;
}
while (cnt) {
send1(rtspi, tx_buf);
tx_buf++;
cnt--;
}
} else if (rx_buf) {
while (cnt >= 4) {
rcv4(rtspi, rx_buf);
rx_buf += 4;
cnt -= 4;
}
while (cnt) {
rcv1(rtspi, rx_buf);
rx_buf++;
cnt--;
}
}
spi_finalize_current_transfer(ctrl);
return 0;
}
static void init_hw(struct rtspi *rtspi)
{
u32 value;
/* Turn on big-endian byte ordering */
value = readl(REG(RTL_SPI_SFCR));
value |= RTL_SPI_SFCR_RBO | RTL_SPI_SFCR_WBO;
writel(value, REG(RTL_SPI_SFCR));
value = readl(REG(RTL_SPI_SFCSR));
/* Permanently disable CS1, since it's never used */
value |= RTL_SPI_SFCSR_CSB1;
/* Select CS0 for use */
value &= RTL_SPI_SFCSR_CS;
writel(value, REG(RTL_SPI_SFCSR));
}
static int realtek_rtl_spi_probe(struct platform_device *pdev)
{
struct spi_controller *ctrl;
struct rtspi *rtspi;
int err;
ctrl = devm_spi_alloc_master(&pdev->dev, sizeof(*rtspi));
if (!ctrl) {
dev_err(&pdev->dev, "Error allocating SPI controller\n");
return -ENOMEM;
}
platform_set_drvdata(pdev, ctrl);
rtspi = spi_controller_get_devdata(ctrl);
rtspi->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
if (IS_ERR(rtspi->base)) {
dev_err(&pdev->dev, "Could not map SPI register address");
return -ENOMEM;
}
init_hw(rtspi);
ctrl->dev.of_node = pdev->dev.of_node;
ctrl->flags = SPI_CONTROLLER_HALF_DUPLEX;
ctrl->set_cs = rt_set_cs;
ctrl->transfer_one = transfer_one;
err = devm_spi_register_controller(&pdev->dev, ctrl);
if (err) {
dev_err(&pdev->dev, "Could not register SPI controller\n");
return -ENODEV;
}
return 0;
}
static const struct of_device_id realtek_rtl_spi_of_ids[] = {
{ .compatible = "realtek,rtl8380-spi" },
{ .compatible = "realtek,rtl8382-spi" },
{ .compatible = "realtek,rtl8391-spi" },
{ .compatible = "realtek,rtl8392-spi" },
{ .compatible = "realtek,rtl8393-spi" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, realtek_rtl_spi_of_ids);
static struct platform_driver realtek_rtl_spi_driver = {
.probe = realtek_rtl_spi_probe,
.driver = {
.name = "realtek-rtl-spi",
.of_match_table = realtek_rtl_spi_of_ids,
},
};
module_platform_driver(realtek_rtl_spi_driver);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Bert Vermeulen <bert@biot.com>");
MODULE_DESCRIPTION("Realtek RTL SPI driver");
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