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path: root/drivers/spi/spi-realtek-rtl.c
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Diffstat (limited to 'drivers/spi/spi-realtek-rtl.c')
-rw-r--r--drivers/spi/spi-realtek-rtl.c209
1 files changed, 209 insertions, 0 deletions
diff --git a/drivers/spi/spi-realtek-rtl.c b/drivers/spi/spi-realtek-rtl.c
new file mode 100644
index 000000000..866b0477d
--- /dev/null
+++ b/drivers/spi/spi-realtek-rtl.c
@@ -0,0 +1,209 @@
+// 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");