--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 Nuvoton Technology corporation.
+
+#include <linux/kernel.h>
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+
+#include <asm/unaligned.h>
+
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+
+struct npcm_pspi {
+ struct completion xfer_done;
+ struct regmap *rst_regmap;
+ struct spi_master *master;
+ unsigned int tx_bytes;
+ unsigned int rx_bytes;
+ void __iomem *base;
+ bool is_save_param;
+ u8 bits_per_word;
+ const u8 *tx_buf;
+ struct clk *clk;
+ u32 speed_hz;
+ u8 *rx_buf;
+ u16 mode;
+ u32 id;
+};
+
+#define DRIVER_NAME "npcm-pspi"
+
+#define NPCM_PSPI_DATA 0x00
+#define NPCM_PSPI_CTL1 0x02
+#define NPCM_PSPI_STAT 0x04
+
+/* definitions for control and status register */
+#define NPCM_PSPI_CTL1_SPIEN BIT(0)
+#define NPCM_PSPI_CTL1_MOD BIT(2)
+#define NPCM_PSPI_CTL1_EIR BIT(5)
+#define NPCM_PSPI_CTL1_EIW BIT(6)
+#define NPCM_PSPI_CTL1_SCM BIT(7)
+#define NPCM_PSPI_CTL1_SCIDL BIT(8)
+#define NPCM_PSPI_CTL1_SCDV6_0 GENMASK(15, 9)
+
+#define NPCM_PSPI_STAT_BSY BIT(0)
+#define NPCM_PSPI_STAT_RBF BIT(1)
+
+/* general definitions */
+#define NPCM_PSPI_TIMEOUT_MS 2000
+#define NPCM_PSPI_MAX_CLK_DIVIDER 256
+#define NPCM_PSPI_MIN_CLK_DIVIDER 4
+#define NPCM_PSPI_DEFAULT_CLK 25000000
+
+/* reset register */
+#define NPCM7XX_IPSRST2_OFFSET 0x24
+
+#define NPCM7XX_PSPI1_RESET BIT(22)
+#define NPCM7XX_PSPI2_RESET BIT(23)
+
+static inline unsigned int bytes_per_word(unsigned int bits)
+{
+ return bits <= 8 ? 1 : 2;
+}
+
+static inline void npcm_pspi_irq_enable(struct npcm_pspi *priv, u16 mask)
+{
+ u16 val;
+
+ val = ioread16(priv->base + NPCM_PSPI_CTL1);
+ val |= mask;
+ iowrite16(val, priv->base + NPCM_PSPI_CTL1);
+}
+
+static inline void npcm_pspi_irq_disable(struct npcm_pspi *priv, u16 mask)
+{
+ u16 val;
+
+ val = ioread16(priv->base + NPCM_PSPI_CTL1);
+ val &= ~mask;
+ iowrite16(val, priv->base + NPCM_PSPI_CTL1);
+}
+
+static inline void npcm_pspi_enable(struct npcm_pspi *priv)
+{
+ u16 val;
+
+ val = ioread16(priv->base + NPCM_PSPI_CTL1);
+ val |= NPCM_PSPI_CTL1_SPIEN;
+ iowrite16(val, priv->base + NPCM_PSPI_CTL1);
+}
+
+static inline void npcm_pspi_disable(struct npcm_pspi *priv)
+{
+ u16 val;
+
+ val = ioread16(priv->base + NPCM_PSPI_CTL1);
+ val &= ~NPCM_PSPI_CTL1_SPIEN;
+ iowrite16(val, priv->base + NPCM_PSPI_CTL1);
+}
+
+static void npcm_pspi_set_mode(struct spi_device *spi)
+{
+ struct npcm_pspi *priv = spi_master_get_devdata(spi->master);
+ u16 regtemp;
+ u16 mode_val;
+
+ switch (spi->mode & (SPI_CPOL | SPI_CPHA)) {
+ case SPI_MODE_0:
+ mode_val = 0;
+ break;
+ case SPI_MODE_1:
+ mode_val = NPCM_PSPI_CTL1_SCIDL;
+ break;
+ case SPI_MODE_2:
+ mode_val = NPCM_PSPI_CTL1_SCM;
+ break;
+ case SPI_MODE_3:
+ mode_val = NPCM_PSPI_CTL1_SCIDL | NPCM_PSPI_CTL1_SCM;
+ break;
+ }
+
+ regtemp = ioread16(priv->base + NPCM_PSPI_CTL1);
+ regtemp &= ~(NPCM_PSPI_CTL1_SCM | NPCM_PSPI_CTL1_SCIDL);
+ iowrite16(regtemp | mode_val, priv->base + NPCM_PSPI_CTL1);
+}
+
+static void npcm_pspi_set_transfer_size(struct npcm_pspi *priv, int size)
+{
+ u16 regtemp;
+
+ regtemp = ioread16(NPCM_PSPI_CTL1 + priv->base);
+
+ switch (size) {
+ case 8:
+ regtemp &= ~NPCM_PSPI_CTL1_MOD;
+ break;
+ case 16:
+ regtemp |= NPCM_PSPI_CTL1_MOD;
+ break;
+ }
+
+ iowrite16(regtemp, NPCM_PSPI_CTL1 + priv->base);
+}
+
+static void npcm_pspi_set_baudrate(struct npcm_pspi *priv, unsigned int speed)
+{
+ u32 ckdiv;
+ u16 regtemp;
+
+ /* the supported rates are numbers from 4 to 256. */
+ ckdiv = DIV_ROUND_CLOSEST(clk_get_rate(priv->clk), (2 * speed)) - 1;
+
+ regtemp = ioread16(NPCM_PSPI_CTL1 + priv->base);
+ regtemp &= ~NPCM_PSPI_CTL1_SCDV6_0;
+ iowrite16(regtemp | (ckdiv << 9), NPCM_PSPI_CTL1 + priv->base);
+}
+
+static void npcm_pspi_setup_transfer(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct npcm_pspi *priv = spi_master_get_devdata(spi->master);
+
+ priv->tx_buf = t->tx_buf;
+ priv->rx_buf = t->rx_buf;
+ priv->tx_bytes = t->len;
+ priv->rx_bytes = t->len;
+
+ if (!priv->is_save_param || priv->mode != spi->mode) {
+ npcm_pspi_set_mode(spi);
+ priv->mode = spi->mode;
+ }
+
+ if (!priv->is_save_param || priv->bits_per_word != t->bits_per_word) {
+ npcm_pspi_set_transfer_size(priv, t->bits_per_word);
+ priv->bits_per_word = t->bits_per_word;
+ }
+
+ if (!priv->is_save_param || priv->speed_hz != t->speed_hz) {
+ npcm_pspi_set_baudrate(priv, t->speed_hz);
+ priv->speed_hz = t->speed_hz;
+ }
+
+ if (!priv->is_save_param)
+ priv->is_save_param = true;
+}
+
+static void npcm_pspi_send(struct npcm_pspi *priv)
+{
+ int wsize;
+
+ wsize = min(bytes_per_word(priv->bits_per_word), priv->tx_bytes);
+ priv->tx_bytes -= wsize;
+
+ if (priv->tx_buf) {
+ if (wsize == 1)
+ iowrite8(*priv->tx_buf, NPCM_PSPI_DATA + priv->base);
+ if (wsize == 2)
+ iowrite16(*priv->tx_buf, NPCM_PSPI_DATA + priv->base);
+
+ priv->tx_buf += wsize;
+ }
+}
+
+static void npcm_pspi_recv(struct npcm_pspi *priv)
+{
+ int rsize;
+ u16 val;
+
+ rsize = min(bytes_per_word(priv->bits_per_word), priv->rx_bytes);
+ priv->rx_bytes -= rsize;
+
+ if (priv->rx_buf) {
+ if (rsize == 1)
+ val = ioread8(priv->base + NPCM_PSPI_DATA);
+ if (rsize == 2)
+ val = ioread16(priv->base + NPCM_PSPI_DATA);
+
+ *priv->rx_buf = val;
+ priv->rx_buf += rsize;
+ }
+}
+
+static int npcm_pspi_transfer_one(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct npcm_pspi *priv = spi_master_get_devdata(master);
+ int status;
+
+ npcm_pspi_setup_transfer(spi, t);
+ reinit_completion(&priv->xfer_done);
+ npcm_pspi_enable(priv);
+ status = wait_for_completion_timeout(&priv->xfer_done,
+ msecs_to_jiffies
+ (NPCM_PSPI_TIMEOUT_MS));
+ if (status == 0) {
+ npcm_pspi_disable(priv);
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+
+static int npcm_pspi_prepare_transfer_hardware(struct spi_master *master)
+{
+ struct npcm_pspi *priv = spi_master_get_devdata(master);
+
+ npcm_pspi_irq_enable(priv, NPCM_PSPI_CTL1_EIR | NPCM_PSPI_CTL1_EIW);
+
+ return 0;
+}
+
+static int npcm_pspi_unprepare_transfer_hardware(struct spi_master *master)
+{
+ struct npcm_pspi *priv = spi_master_get_devdata(master);
+
+ npcm_pspi_irq_disable(priv, NPCM_PSPI_CTL1_EIR | NPCM_PSPI_CTL1_EIW);
+
+ return 0;
+}
+
+static void npcm_pspi_reset_hw(struct npcm_pspi *priv)
+{
+ regmap_write(priv->rst_regmap, NPCM7XX_IPSRST2_OFFSET,
+ NPCM7XX_PSPI1_RESET << priv->id);
+ regmap_write(priv->rst_regmap, NPCM7XX_IPSRST2_OFFSET, 0x0);
+}
+
+static irqreturn_t npcm_pspi_handler(int irq, void *dev_id)
+{
+ struct npcm_pspi *priv = dev_id;
+ u16 val;
+ u8 stat;
+
+ stat = ioread8(priv->base + NPCM_PSPI_STAT);
+
+ if (!priv->tx_buf && !priv->rx_buf)
+ return IRQ_NONE;
+
+ if (priv->tx_buf) {
+ if (stat & NPCM_PSPI_STAT_RBF) {
+ val = ioread8(NPCM_PSPI_DATA + priv->base);
+ if (priv->tx_bytes == 0) {
+ npcm_pspi_disable(priv);
+ complete(&priv->xfer_done);
+ return IRQ_HANDLED;
+ }
+ }
+
+ if ((stat & NPCM_PSPI_STAT_BSY) == 0)
+ if (priv->tx_bytes)
+ npcm_pspi_send(priv);
+ }
+
+ if (priv->rx_buf) {
+ if (stat & NPCM_PSPI_STAT_RBF) {
+ if (!priv->rx_bytes)
+ return IRQ_NONE;
+
+ npcm_pspi_recv(priv);
+
+ if (!priv->rx_bytes) {
+ npcm_pspi_disable(priv);
+ complete(&priv->xfer_done);
+ return IRQ_HANDLED;
+ }
+ }
+
+ if (((stat & NPCM_PSPI_STAT_BSY) == 0) && !priv->tx_buf)
+ iowrite8(0x0, NPCM_PSPI_DATA + priv->base);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int npcm_pspi_probe(struct platform_device *pdev)
+{
+ struct npcm_pspi *priv;
+ struct spi_master *master;
+ struct resource *res;
+ unsigned long clk_hz;
+ struct device_node *np = pdev->dev.of_node;
+ int num_cs, i;
+ u32 csgpio;
+ int irq;
+ int ret;
+
+ num_cs = of_gpio_named_count(np, "cs-gpios");
+ if (num_cs < 0)
+ return num_cs;
+
+ pdev->id = of_alias_get_id(np, "spi");
+ if (pdev->id < 0)
+ pdev->id = 0;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(*priv));
+ if (!master)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, master);
+
+ priv = spi_master_get_devdata(master);
+ priv->master = master;
+ priv->is_save_param = false;
+ priv->id = pdev->id;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ priv->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(priv->base)) {
+ ret = PTR_ERR(priv->base);
+ goto out_master_put;
+ }
+
+ priv->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(priv->clk)) {
+ dev_err(&pdev->dev, "failed to get clock\n");
+ ret = PTR_ERR(priv->clk);
+ goto out_master_put;
+ }
+
+ ret = clk_prepare_enable(priv->clk);
+ if (ret)
+ goto out_master_put;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "failed to get IRQ\n");
+ ret = irq;
+ goto out_disable_clk;
+ }
+
+ priv->rst_regmap =
+ syscon_regmap_lookup_by_compatible("nuvoton,npcm750-rst");
+ if (IS_ERR(priv->rst_regmap)) {
+ dev_err(&pdev->dev, "failed to find nuvoton,npcm750-rst\n");
+ return IS_ERR(priv->rst_regmap);
+ }
+
+ /* reset SPI-HW block */
+ npcm_pspi_reset_hw(priv);
+
+ ret = devm_request_irq(&pdev->dev, irq, npcm_pspi_handler, 0,
+ "npcm-pspi", priv);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to request IRQ\n");
+ goto out_disable_clk;
+ }
+
+ init_completion(&priv->xfer_done);
+
+ clk_hz = clk_get_rate(priv->clk);
+
+ master->max_speed_hz = DIV_ROUND_UP(clk_hz, NPCM_PSPI_MIN_CLK_DIVIDER);
+ master->min_speed_hz = DIV_ROUND_UP(clk_hz, NPCM_PSPI_MAX_CLK_DIVIDER);
+ master->mode_bits = SPI_CPHA | SPI_CPOL;
+ master->dev.of_node = pdev->dev.of_node;
+ master->bus_num = pdev->id;
+ master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
+ master->transfer_one = npcm_pspi_transfer_one;
+ master->prepare_transfer_hardware =
+ npcm_pspi_prepare_transfer_hardware;
+ master->unprepare_transfer_hardware =
+ npcm_pspi_unprepare_transfer_hardware;
+ master->num_chipselect = num_cs;
+
+ for (i = 0; i < num_cs; i++) {
+ csgpio = of_get_named_gpio(np, "cs-gpios", i);
+ if (csgpio < 0) {
+ dev_err(&pdev->dev, "failed to get csgpio#%u\n", i);
+ goto out_disable_clk;
+ }
+ dev_dbg(&pdev->dev, "csgpio#%u = %u\n", i, csgpio);
+ ret = devm_gpio_request_one(&pdev->dev, csgpio,
+ GPIOF_OUT_INIT_HIGH, DRIVER_NAME);
+ if (ret < 0) {
+ dev_err(&pdev->dev,
+ "failed to configure csgpio#%u %u\n"
+ , i, csgpio);
+ goto out_disable_clk;
+ }
+ }
+
+ /* set to default clock rate */
+ npcm_pspi_set_baudrate(priv, NPCM_PSPI_DEFAULT_CLK);
+
+ ret = devm_spi_register_master(&pdev->dev, master);
+ if (ret)
+ goto out_disable_clk;
+
+ pr_info("NPCM Peripheral SPI %d probed\n", pdev->id);
+
+ return 0;
+
+out_disable_clk:
+ clk_disable_unprepare(priv->clk);
+
+out_master_put:
+ spi_master_put(master);
+ return ret;
+}
+
+static int npcm_pspi_remove(struct platform_device *pdev)
+{
+ struct npcm_pspi *priv = platform_get_drvdata(pdev);
+
+ npcm_pspi_reset_hw(priv);
+ clk_disable_unprepare(priv->clk);
+
+ return 0;
+}
+
+static const struct of_device_id npcm_pspi_match[] = {
+ { .compatible = "nuvoton,npcm750-pspi", .data = NULL },
+ {}
+};
+MODULE_DEVICE_TABLE(of, npcm_pspi_match);
+
+static struct platform_driver npcm_pspi_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ .of_match_table = npcm_pspi_match,
+ .owner = THIS_MODULE,
+ },
+ .probe = npcm_pspi_probe,
+ .remove = npcm_pspi_remove,
+};
+module_platform_driver(npcm_pspi_driver);
+
+MODULE_DESCRIPTION("NPCM peripheral SPI Controller driver");
+MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");
+MODULE_LICENSE("GPL v2");
+
projects / platform / kernel / linux-rpi.git / commitdiff