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path: root/drivers/spi/spi-uniphier.c
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Diffstat (limited to 'drivers/spi/spi-uniphier.c')
-rw-r--r--drivers/spi/spi-uniphier.c523
1 files changed, 523 insertions, 0 deletions
diff --git a/drivers/spi/spi-uniphier.c b/drivers/spi/spi-uniphier.c
new file mode 100644
index 000000000000..5a6137fe172d
--- /dev/null
+++ b/drivers/spi/spi-uniphier.c
@@ -0,0 +1,523 @@
+// SPDX-License-Identifier: GPL-2.0
+// spi-uniphier.c - Socionext UniPhier SPI controller driver
+// Copyright 2012 Panasonic Corporation
+// Copyright 2016-2018 Socionext Inc.
+
+#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 <asm/unaligned.h>
+
+#define SSI_TIMEOUT_MS 2000
+#define SSI_MAX_CLK_DIVIDER 254
+#define SSI_MIN_CLK_DIVIDER 4
+
+struct uniphier_spi_priv {
+ void __iomem *base;
+ struct clk *clk;
+ struct spi_master *master;
+ struct completion xfer_done;
+
+ int error;
+ unsigned int tx_bytes;
+ unsigned int rx_bytes;
+ const u8 *tx_buf;
+ u8 *rx_buf;
+
+ bool is_save_param;
+ u8 bits_per_word;
+ u16 mode;
+ u32 speed_hz;
+};
+
+#define SSI_CTL 0x00
+#define SSI_CTL_EN BIT(0)
+
+#define SSI_CKS 0x04
+#define SSI_CKS_CKRAT_MASK GENMASK(7, 0)
+#define SSI_CKS_CKPHS BIT(14)
+#define SSI_CKS_CKINIT BIT(13)
+#define SSI_CKS_CKDLY BIT(12)
+
+#define SSI_TXWDS 0x08
+#define SSI_TXWDS_WDLEN_MASK GENMASK(13, 8)
+#define SSI_TXWDS_TDTF_MASK GENMASK(7, 6)
+#define SSI_TXWDS_DTLEN_MASK GENMASK(5, 0)
+
+#define SSI_RXWDS 0x0c
+#define SSI_RXWDS_DTLEN_MASK GENMASK(5, 0)
+
+#define SSI_FPS 0x10
+#define SSI_FPS_FSPOL BIT(15)
+#define SSI_FPS_FSTRT BIT(14)
+
+#define SSI_SR 0x14
+#define SSI_SR_RNE BIT(0)
+
+#define SSI_IE 0x18
+#define SSI_IE_RCIE BIT(3)
+#define SSI_IE_RORIE BIT(0)
+
+#define SSI_IS 0x1c
+#define SSI_IS_RXRS BIT(9)
+#define SSI_IS_RCID BIT(3)
+#define SSI_IS_RORID BIT(0)
+
+#define SSI_IC 0x1c
+#define SSI_IC_TCIC BIT(4)
+#define SSI_IC_RCIC BIT(3)
+#define SSI_IC_RORIC BIT(0)
+
+#define SSI_FC 0x20
+#define SSI_FC_TXFFL BIT(12)
+#define SSI_FC_TXFTH_MASK GENMASK(11, 8)
+#define SSI_FC_RXFFL BIT(4)
+#define SSI_FC_RXFTH_MASK GENMASK(3, 0)
+
+#define SSI_TXDR 0x24
+#define SSI_RXDR 0x24
+
+#define SSI_FIFO_DEPTH 8U
+
+static inline unsigned int bytes_per_word(unsigned int bits)
+{
+ return bits <= 8 ? 1 : (bits <= 16 ? 2 : 4);
+}
+
+static inline void uniphier_spi_irq_enable(struct spi_device *spi, u32 mask)
+{
+ struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
+ u32 val;
+
+ val = readl(priv->base + SSI_IE);
+ val |= mask;
+ writel(val, priv->base + SSI_IE);
+}
+
+static inline void uniphier_spi_irq_disable(struct spi_device *spi, u32 mask)
+{
+ struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
+ u32 val;
+
+ val = readl(priv->base + SSI_IE);
+ val &= ~mask;
+ writel(val, priv->base + SSI_IE);
+}
+
+static void uniphier_spi_set_mode(struct spi_device *spi)
+{
+ struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
+ u32 val1, val2;
+
+ /*
+ * clock setting
+ * CKPHS capture timing. 0:rising edge, 1:falling edge
+ * CKINIT clock initial level. 0:low, 1:high
+ * CKDLY clock delay. 0:no delay, 1:delay depending on FSTRT
+ * (FSTRT=0: 1 clock, FSTRT=1: 0.5 clock)
+ *
+ * frame setting
+ * FSPOL frame signal porarity. 0: low, 1: high
+ * FSTRT start frame timing
+ * 0: rising edge of clock, 1: falling edge of clock
+ */
+ switch (spi->mode & (SPI_CPOL | SPI_CPHA)) {
+ case SPI_MODE_0:
+ /* CKPHS=1, CKINIT=0, CKDLY=1, FSTRT=0 */
+ val1 = SSI_CKS_CKPHS | SSI_CKS_CKDLY;
+ val2 = 0;
+ break;
+ case SPI_MODE_1:
+ /* CKPHS=0, CKINIT=0, CKDLY=0, FSTRT=1 */
+ val1 = 0;
+ val2 = SSI_FPS_FSTRT;
+ break;
+ case SPI_MODE_2:
+ /* CKPHS=0, CKINIT=1, CKDLY=1, FSTRT=1 */
+ val1 = SSI_CKS_CKINIT | SSI_CKS_CKDLY;
+ val2 = SSI_FPS_FSTRT;
+ break;
+ case SPI_MODE_3:
+ /* CKPHS=1, CKINIT=1, CKDLY=0, FSTRT=0 */
+ val1 = SSI_CKS_CKPHS | SSI_CKS_CKINIT;
+ val2 = 0;
+ break;
+ }
+
+ if (!(spi->mode & SPI_CS_HIGH))
+ val2 |= SSI_FPS_FSPOL;
+
+ writel(val1, priv->base + SSI_CKS);
+ writel(val2, priv->base + SSI_FPS);
+
+ val1 = 0;
+ if (spi->mode & SPI_LSB_FIRST)
+ val1 |= FIELD_PREP(SSI_TXWDS_TDTF_MASK, 1);
+ writel(val1, priv->base + SSI_TXWDS);
+ writel(val1, priv->base + SSI_RXWDS);
+}
+
+static void uniphier_spi_set_transfer_size(struct spi_device *spi, int size)
+{
+ struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
+ u32 val;
+
+ val = readl(priv->base + SSI_TXWDS);
+ val &= ~(SSI_TXWDS_WDLEN_MASK | SSI_TXWDS_DTLEN_MASK);
+ val |= FIELD_PREP(SSI_TXWDS_WDLEN_MASK, size);
+ val |= FIELD_PREP(SSI_TXWDS_DTLEN_MASK, size);
+ writel(val, priv->base + SSI_TXWDS);
+
+ val = readl(priv->base + SSI_RXWDS);
+ val &= ~SSI_RXWDS_DTLEN_MASK;
+ val |= FIELD_PREP(SSI_RXWDS_DTLEN_MASK, size);
+ writel(val, priv->base + SSI_RXWDS);
+}
+
+static void uniphier_spi_set_baudrate(struct spi_device *spi,
+ unsigned int speed)
+{
+ struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
+ u32 val, ckdiv;
+
+ /*
+ * the supported rates are even numbers from 4 to 254. (4,6,8...254)
+ * round up as we look for equal or less speed
+ */
+ ckdiv = DIV_ROUND_UP(clk_get_rate(priv->clk), speed);
+ ckdiv = round_up(ckdiv, 2);
+
+ val = readl(priv->base + SSI_CKS);
+ val &= ~SSI_CKS_CKRAT_MASK;
+ val |= ckdiv & SSI_CKS_CKRAT_MASK;
+ writel(val, priv->base + SSI_CKS);
+}
+
+static void uniphier_spi_setup_transfer(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
+ u32 val;
+
+ priv->error = 0;
+ priv->tx_buf = t->tx_buf;
+ priv->rx_buf = t->rx_buf;
+ priv->tx_bytes = priv->rx_bytes = t->len;
+
+ if (!priv->is_save_param || priv->mode != spi->mode) {
+ uniphier_spi_set_mode(spi);
+ priv->mode = spi->mode;
+ }
+
+ if (!priv->is_save_param || priv->bits_per_word != t->bits_per_word) {
+ uniphier_spi_set_transfer_size(spi, t->bits_per_word);
+ priv->bits_per_word = t->bits_per_word;
+ }
+
+ if (!priv->is_save_param || priv->speed_hz != t->speed_hz) {
+ uniphier_spi_set_baudrate(spi, t->speed_hz);
+ priv->speed_hz = t->speed_hz;
+ }
+
+ if (!priv->is_save_param)
+ priv->is_save_param = true;
+
+ /* reset FIFOs */
+ val = SSI_FC_TXFFL | SSI_FC_RXFFL;
+ writel(val, priv->base + SSI_FC);
+}
+
+static void uniphier_spi_send(struct uniphier_spi_priv *priv)
+{
+ int wsize;
+ u32 val = 0;
+
+ wsize = min(bytes_per_word(priv->bits_per_word), priv->tx_bytes);
+ priv->tx_bytes -= wsize;
+
+ if (priv->tx_buf) {
+ switch (wsize) {
+ case 1:
+ val = *priv->tx_buf;
+ break;
+ case 2:
+ val = get_unaligned_le16(priv->tx_buf);
+ break;
+ case 4:
+ val = get_unaligned_le32(priv->tx_buf);
+ break;
+ }
+
+ priv->tx_buf += wsize;
+ }
+
+ writel(val, priv->base + SSI_TXDR);
+}
+
+static void uniphier_spi_recv(struct uniphier_spi_priv *priv)
+{
+ int rsize;
+ u32 val;
+
+ rsize = min(bytes_per_word(priv->bits_per_word), priv->rx_bytes);
+ priv->rx_bytes -= rsize;
+
+ val = readl(priv->base + SSI_RXDR);
+
+ if (priv->rx_buf) {
+ switch (rsize) {
+ case 1:
+ *priv->rx_buf = val;
+ break;
+ case 2:
+ put_unaligned_le16(val, priv->rx_buf);
+ break;
+ case 4:
+ put_unaligned_le32(val, priv->rx_buf);
+ break;
+ }
+
+ priv->rx_buf += rsize;
+ }
+}
+
+static void uniphier_spi_fill_tx_fifo(struct uniphier_spi_priv *priv)
+{
+ unsigned int tx_count;
+ u32 val;
+
+ tx_count = DIV_ROUND_UP(priv->tx_bytes,
+ bytes_per_word(priv->bits_per_word));
+ tx_count = min(tx_count, SSI_FIFO_DEPTH);
+
+ /* set fifo threshold */
+ val = readl(priv->base + SSI_FC);
+ val &= ~(SSI_FC_TXFTH_MASK | SSI_FC_RXFTH_MASK);
+ val |= FIELD_PREP(SSI_FC_TXFTH_MASK, tx_count);
+ val |= FIELD_PREP(SSI_FC_RXFTH_MASK, tx_count);
+ writel(val, priv->base + SSI_FC);
+
+ while (tx_count--)
+ uniphier_spi_send(priv);
+}
+
+static void uniphier_spi_set_cs(struct spi_device *spi, bool enable)
+{
+ struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
+ u32 val;
+
+ val = readl(priv->base + SSI_FPS);
+
+ if (enable)
+ val |= SSI_FPS_FSPOL;
+ else
+ val &= ~SSI_FPS_FSPOL;
+
+ writel(val, priv->base + SSI_FPS);
+}
+
+static int uniphier_spi_transfer_one(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct uniphier_spi_priv *priv = spi_master_get_devdata(master);
+ int status;
+
+ uniphier_spi_setup_transfer(spi, t);
+
+ reinit_completion(&priv->xfer_done);
+
+ uniphier_spi_fill_tx_fifo(priv);
+
+ uniphier_spi_irq_enable(spi, SSI_IE_RCIE | SSI_IE_RORIE);
+
+ status = wait_for_completion_timeout(&priv->xfer_done,
+ msecs_to_jiffies(SSI_TIMEOUT_MS));
+
+ uniphier_spi_irq_disable(spi, SSI_IE_RCIE | SSI_IE_RORIE);
+
+ if (status < 0)
+ return status;
+
+ return priv->error;
+}
+
+static int uniphier_spi_prepare_transfer_hardware(struct spi_master *master)
+{
+ struct uniphier_spi_priv *priv = spi_master_get_devdata(master);
+
+ writel(SSI_CTL_EN, priv->base + SSI_CTL);
+
+ return 0;
+}
+
+static int uniphier_spi_unprepare_transfer_hardware(struct spi_master *master)
+{
+ struct uniphier_spi_priv *priv = spi_master_get_devdata(master);
+
+ writel(0, priv->base + SSI_CTL);
+
+ return 0;
+}
+
+static irqreturn_t uniphier_spi_handler(int irq, void *dev_id)
+{
+ struct uniphier_spi_priv *priv = dev_id;
+ u32 val, stat;
+
+ stat = readl(priv->base + SSI_IS);
+ val = SSI_IC_TCIC | SSI_IC_RCIC | SSI_IC_RORIC;
+ writel(val, priv->base + SSI_IC);
+
+ /* rx fifo overrun */
+ if (stat & SSI_IS_RORID) {
+ priv->error = -EIO;
+ goto done;
+ }
+
+ /* rx complete */
+ if ((stat & SSI_IS_RCID) && (stat & SSI_IS_RXRS)) {
+ while ((readl(priv->base + SSI_SR) & SSI_SR_RNE) &&
+ (priv->rx_bytes - priv->tx_bytes) > 0)
+ uniphier_spi_recv(priv);
+
+ if ((readl(priv->base + SSI_SR) & SSI_SR_RNE) ||
+ (priv->rx_bytes != priv->tx_bytes)) {
+ priv->error = -EIO;
+ goto done;
+ } else if (priv->rx_bytes == 0)
+ goto done;
+
+ /* next tx transfer */
+ uniphier_spi_fill_tx_fifo(priv);
+
+ return IRQ_HANDLED;
+ }
+
+ return IRQ_NONE;
+
+done:
+ complete(&priv->xfer_done);
+ return IRQ_HANDLED;
+}
+
+static int uniphier_spi_probe(struct platform_device *pdev)
+{
+ struct uniphier_spi_priv *priv;
+ struct spi_master *master;
+ struct resource *res;
+ unsigned long clk_rate;
+ int irq;
+ int ret;
+
+ 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;
+
+ 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;
+ }
+
+ ret = devm_request_irq(&pdev->dev, irq, uniphier_spi_handler,
+ 0, "uniphier-spi", priv);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to request IRQ\n");
+ goto out_disable_clk;
+ }
+
+ init_completion(&priv->xfer_done);
+
+ clk_rate = clk_get_rate(priv->clk);
+
+ master->max_speed_hz = DIV_ROUND_UP(clk_rate, SSI_MIN_CLK_DIVIDER);
+ master->min_speed_hz = DIV_ROUND_UP(clk_rate, SSI_MAX_CLK_DIVIDER);
+ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
+ master->dev.of_node = pdev->dev.of_node;
+ master->bus_num = pdev->id;
+ master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
+
+ master->set_cs = uniphier_spi_set_cs;
+ master->transfer_one = uniphier_spi_transfer_one;
+ master->prepare_transfer_hardware
+ = uniphier_spi_prepare_transfer_hardware;
+ master->unprepare_transfer_hardware
+ = uniphier_spi_unprepare_transfer_hardware;
+ master->num_chipselect = 1;
+
+ ret = devm_spi_register_master(&pdev->dev, master);
+ if (ret)
+ goto out_disable_clk;
+
+ return 0;
+
+out_disable_clk:
+ clk_disable_unprepare(priv->clk);
+
+out_master_put:
+ spi_master_put(master);
+ return ret;
+}
+
+static int uniphier_spi_remove(struct platform_device *pdev)
+{
+ struct uniphier_spi_priv *priv = platform_get_drvdata(pdev);
+
+ clk_disable_unprepare(priv->clk);
+
+ return 0;
+}
+
+static const struct of_device_id uniphier_spi_match[] = {
+ { .compatible = "socionext,uniphier-scssi" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, uniphier_spi_match);
+
+static struct platform_driver uniphier_spi_driver = {
+ .probe = uniphier_spi_probe,
+ .remove = uniphier_spi_remove,
+ .driver = {
+ .name = "uniphier-spi",
+ .of_match_table = uniphier_spi_match,
+ },
+};
+module_platform_driver(uniphier_spi_driver);
+
+MODULE_AUTHOR("Kunihiko Hayashi <[email protected]>");
+MODULE_AUTHOR("Keiji Hayashibara <[email protected]>");
+MODULE_DESCRIPTION("Socionext UniPhier SPI controller driver");
+MODULE_LICENSE("GPL v2");
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