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