Message-ID: <20251112034724.1977630-3-cl634@andestech.com>
Date: Wed, 12 Nov 2025 11:47:24 +0800
From: CL Wang <cl634@...estech.com>
To: <cl634@...estech.com>, <broonie@...nel.org>, <linux-spi@...r.kernel.org>,
        <robh@...nel.org>, <krzk+dt@...nel.org>, <conor+dt@...nel.org>
CC: <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <tim609@...estech.com>
Subject: [PATCH 2/2] spi: atcspi200: Add ATCSPI200 SPI driver

SPI driver for Andes ATCSPI200 SPI controller.

Signed-off-by: CL Wang <cl634@...estech.com>
---
 drivers/spi/Kconfig         |   9 +
 drivers/spi/Makefile        |   1 +
 drivers/spi/spi-atcspi200.c | 651 ++++++++++++++++++++++++++++++++++++
 3 files changed, 661 insertions(+)
 create mode 100644 drivers/spi/spi-atcspi200.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 592d46c9998b..b2e35f55aa88 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -136,6 +136,15 @@ config SPI_AR934X
 	  This enables support for the SPI controller present on the
 	  Qualcomm Atheros AR934X/QCA95XX SoCs.
 
+config SPI_ATCSPI200
+	tristate "Andes ATCSPI200 SPI controller"
+	depends on ARCH_ANDES
+	help
+	  SPI driver for Andes ATCSPI200 SPI controller.
+	  ATCSPI200 controller supports DMA and PIO modes. When DMA
+	  is not available, the driver automatically falls back to
+	  PIO mode.
+
 config SPI_ATH79
 	tristate "Atheros AR71XX/AR724X/AR913X SPI controller driver"
 	depends on ATH79 || COMPILE_TEST
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 8ff74a13faaa..869d6fbc53f8 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_SPI_APPLE)			+= spi-apple.o
 obj-$(CONFIG_SPI_AR934X)		+= spi-ar934x.o
 obj-$(CONFIG_SPI_ARMADA_3700)		+= spi-armada-3700.o
 obj-$(CONFIG_SPI_ASPEED_SMC)		+= spi-aspeed-smc.o
+obj-$(CONFIG_SPI_ATCSPI200)		+= spi-atcspi200.o
 obj-$(CONFIG_SPI_ATMEL)			+= spi-atmel.o
 obj-$(CONFIG_SPI_ATMEL_QUADSPI)		+= atmel-quadspi.o
 obj-$(CONFIG_SPI_AT91_USART)		+= spi-at91-usart.o
diff --git a/drivers/spi/spi-atcspi200.c b/drivers/spi/spi-atcspi200.c
new file mode 100644
index 000000000000..65ffbaaf9124
--- /dev/null
+++ b/drivers/spi/spi-atcspi200.c
@@ -0,0 +1,651 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for Andes ATCSPI200 SPI Controller
+ *
+ * Copyright (C) 2025 Andes Technology Corporation.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/dev_printk.h>
+#include <linux/dmaengine.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/jiffies.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi-mem.h>
+
+/* Register definitions  */
+#define ATCSPI_TRANS_FMT	0x10	/* SPI transfer format register */
+#define ATCSPI_TRANS_CTRL	0x20	/* SPI transfer control register */
+#define ATCSPI_CMD		0x24	/* SPI command register */
+#define ATCSPI_ADDR		0x28	/* SPI address register */
+#define ATCSPI_DATA		0x2C	/* SPI data register */
+#define ATCSPI_CTRL		0x30	/* SPI control register */
+#define ATCSPI_STATUS		0x34	/* SPI status register */
+#define ATCSPI_TIMING		0x40	/* SPI interface timing register */
+#define ATCSPI_CONFIG		0x7C	/* SPI configuration register */
+
+/* Transfer format register */
+#define TRANS_FMT_CPHA		BIT(0)
+#define TRANS_FMT_CPOL		BIT(1)
+#define TRANS_FMT_DATA_MERGE_EN	BIT(7)
+#define TRANS_FMT_DATA_LEN_MASK	GENMASK(12, 8)
+#define TRANS_FMT_ADDR_LEN_MASK	GENMASK(17, 16)
+#define TRANS_FMT_DATA_LEN(x)	FIELD_PREP(TRANS_FMT_DATA_LEN_MASK, (x) - 1)
+#define TRANS_FMT_ADDR_LEN(x)	FIELD_PREP(TRANS_FMT_ADDR_LEN_MASK, (x) - 1)
+
+/* Transfer control register */
+#define TRANS_MODE_MASK		GENMASK(27, 24)
+#define TRANS_MODE_W_ONLY	FIELD_PREP(TRANS_MODE_MASK, 1)
+#define TRANS_MODE_R_ONLY	FIELD_PREP(TRANS_MODE_MASK, 2)
+#define TRANS_MODE_NONE_DATA	FIELD_PREP(TRANS_MODE_MASK, 7)
+#define TRANS_MODE_DMY_READ	FIELD_PREP(TRANS_MODE_MASK, 9)
+#define TRANS_FIELD_DECNZ(m, x)	((x) ? FIELD_PREP(m, (x) - 1) : 0)
+#define TRANS_RD_TRANS_CNT(x)	TRANS_FIELD_DECNZ(GENMASK(8, 0), x)
+#define TRANS_DUMMY_CNT(x)	TRANS_FIELD_DECNZ(GENMASK(10, 9), x)
+#define TRANS_WR_TRANS_CNT(x)	TRANS_FIELD_DECNZ(GENMASK(20, 12), x)
+#define TRANS_DUAL_QUAD(x)	FIELD_PREP(GENMASK(23, 22), (x))
+#define TRANS_ADDR_FMT		BIT(28)
+#define TRANS_ADDR_EN		BIT(29)
+#define TRANS_CMD_EN		BIT(30)
+
+/* Control register */
+#define CTRL_SPI_RST		BIT(0)
+#define CTRL_RX_FIFO_RST	BIT(1)
+#define CTRL_TX_FIFO_RST	BIT(2)
+#define CTRL_RX_DMA_EN		BIT(3)
+#define CTRL_TX_DMA_EN		BIT(4)
+
+/* Status register */
+#define ATCSPI_ACTIVE		BIT(0)
+#define ATCSPI_RX_EMPTY		BIT(14)
+#define ATCSPI_TX_FULL		BIT(23)
+
+/* Interface timing setting */
+#define TIMING_SCLK_DIV_MASK	GENMASK(7, 0)
+#define TIMING_SCLK_DIV_MAX	0xFE
+
+/* Configuration register */
+#define RXFIFO_SIZE(x)		FIELD_GET(GENMASK(3, 0), (x))
+#define TXFIFO_SIZE(x)		FIELD_GET(GENMASK(7, 4), (x))
+
+/* driver configurations */
+#define ATCSPI_MAX_TRANS_LEN	512
+#define ATCSPI_MAX_SPEED_HZ	50000000
+#define ATCSPI_RDY_TIMEOUT_US	1000000
+#define ATCSPI_XFER_TIMEOUT(n)	((n) * 10)
+#define ATCSPI_MAX_CS_NUM	1
+#define ATCSPI_DMA_THRESHOLD	256
+#define ATCSPI_BITS_PER_UINT	8
+#define ATCSPI_DATA_MERGE_EN	1
+#define ATCSPI_DMA_SUPPORT	1
+
+/**
+ * struct atcspi_dev - Andes ATCSPI200 SPI controller private data
+ * @host:           Pointer to the SPI controller structure.
+ * @mutex_lock:     A mutex to protect concurrent access to the controller.
+ * @dma_completion: A completion to signal the end of a DMA transfer.
+ * @dev:            Pointer to the device structure.
+ * @regmap:         Register map for accessing controller registers.
+ * @clk:            Pointer to the controller's functional clock.
+ * @dma_addr:       The physical address of the SPI data register for DMA.
+ * @clk_rate:       The cached frequency of the functional clock.
+ * @sclk_rate:      The target frequency for the SPI clock (SCLK).
+ * @txfifo_size:    The size of the transmit FIFO in bytes.
+ * @rxfifo_size:    The size of the receive FIFO in bytes.
+ * @data_merge:     A flag indicating if the data merge mode is enabled for
+ *                  the current transfer.
+ * @use_dma:        Enable DMA mode if ATCSPI_DMA_SUPPORT is set and DMA is
+ *                  successfully configured.
+ */
+struct atcspi_dev {
+	struct spi_controller	*host;
+	struct mutex		mutex_lock;
+	struct completion	dma_completion;
+	struct device		*dev;
+	struct regmap		*regmap;
+	struct clk		*clk;
+	dma_addr_t		dma_addr;
+	unsigned int		clk_rate;
+	unsigned int		sclk_rate;
+	unsigned int		txfifo_size;
+	unsigned int		rxfifo_size;
+	bool			data_merge;
+	bool			use_dma;
+};
+
+static int atcspi_wait_fifo_ready(struct atcspi_dev *spi,
+				  enum spi_mem_data_dir dir)
+{
+	unsigned int val;
+	unsigned int mask;
+	int ret;
+
+	mask = (dir == SPI_MEM_DATA_OUT) ? ATCSPI_TX_FULL : ATCSPI_RX_EMPTY;
+	ret = regmap_read_poll_timeout(spi->regmap,
+				       ATCSPI_STATUS,
+				       val,
+				       !(val & mask),
+				       0,
+				       ATCSPI_RDY_TIMEOUT_US);
+	if (ret)
+		dev_info(spi->dev, "Timed out waiting for FIFO ready\n");
+
+	return ret;
+}
+
+static int atcspi_xfer_data_poll(struct atcspi_dev *spi,
+				 const struct spi_mem_op *op)
+{
+	void *rx_buf = op->data.buf.in;
+	const void *tx_buf = op->data.buf.out;
+	unsigned int val;
+	int trans_bytes = op->data.nbytes;
+	int num_byte;
+	int ret = 0;
+
+	num_byte = spi->data_merge ? 4 : 1;
+	while (trans_bytes) {
+		if (op->data.dir == SPI_MEM_DATA_OUT) {
+			ret = atcspi_wait_fifo_ready(spi, SPI_MEM_DATA_OUT);
+			if (ret)
+				return ret;
+
+			if (spi->data_merge)
+				val = *(unsigned int *)tx_buf;
+			else
+				val = *(unsigned char *)tx_buf;
+			regmap_write(spi->regmap, ATCSPI_DATA, val);
+			tx_buf = (unsigned char *)tx_buf + num_byte;
+		} else {
+			ret = atcspi_wait_fifo_ready(spi, SPI_MEM_DATA_IN);
+			if (ret)
+				return ret;
+
+			regmap_read(spi->regmap, ATCSPI_DATA, &val);
+			if (spi->data_merge)
+				*(unsigned int *)rx_buf = val;
+			else
+				*(unsigned char *)rx_buf = (unsigned char)val;
+			rx_buf = (unsigned char *)rx_buf + num_byte;
+		}
+		trans_bytes -= num_byte;
+	}
+
+	return ret;
+}
+
+static void atcspi_set_trans_ctl(struct atcspi_dev *spi,
+				 const struct spi_mem_op *op)
+{
+	unsigned int tc = 0;
+
+	if (op->cmd.nbytes)
+		tc |= TRANS_CMD_EN;
+	if (op->addr.nbytes)
+		tc |= TRANS_ADDR_EN;
+	if (op->addr.buswidth > 1)
+		tc |= TRANS_ADDR_FMT;
+	if (op->data.nbytes) {
+		tc |= TRANS_DUAL_QUAD(ffs(op->data.buswidth) - 1);
+		if (op->data.dir == SPI_MEM_DATA_IN) {
+			if (op->dummy.nbytes)
+				tc |= TRANS_MODE_DMY_READ |
+				      TRANS_DUMMY_CNT(op->dummy.nbytes);
+			else
+				tc |= TRANS_MODE_R_ONLY;
+			tc |= TRANS_RD_TRANS_CNT(op->data.nbytes);
+		} else {
+			tc |= TRANS_MODE_W_ONLY |
+			      TRANS_WR_TRANS_CNT(op->data.nbytes);
+		}
+	} else {
+		tc |= TRANS_MODE_NONE_DATA;
+	}
+	regmap_write(spi->regmap, ATCSPI_TRANS_CTRL, tc);
+}
+
+static void atcspi_set_trans_fmt(struct atcspi_dev *spi,
+				 const struct spi_mem_op *op)
+{
+	unsigned int val;
+
+	regmap_read(spi->regmap, ATCSPI_TRANS_FMT, &val);
+	if (op->data.nbytes) {
+		if (ATCSPI_DATA_MERGE_EN && ATCSPI_BITS_PER_UINT == 8 &&
+		    !(op->data.nbytes % 4)) {
+			val |= TRANS_FMT_DATA_MERGE_EN;
+			spi->data_merge = true;
+		} else {
+			val &= ~TRANS_FMT_DATA_MERGE_EN;
+			spi->data_merge = false;
+		}
+	}
+
+	val = (val & ~TRANS_FMT_ADDR_LEN_MASK) |
+	      TRANS_FMT_ADDR_LEN(op->addr.nbytes);
+	regmap_write(spi->regmap, ATCSPI_TRANS_FMT, val);
+}
+
+static void atcspi_prepare_trans(struct atcspi_dev *spi,
+				 const struct spi_mem_op *op)
+{
+	atcspi_set_trans_fmt(spi, op);
+	atcspi_set_trans_ctl(spi, op);
+	if (op->addr.nbytes)
+		regmap_write(spi->regmap, ATCSPI_ADDR, op->addr.val);
+	regmap_write(spi->regmap, ATCSPI_CMD, op->cmd.opcode);
+}
+
+static int atcspi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
+{
+	struct atcspi_dev *spi;
+
+	spi = spi_controller_get_devdata(mem->spi->controller);
+	op->data.nbytes = min(op->data.nbytes, ATCSPI_MAX_TRANS_LEN);
+
+	/* DMA needs to be aligned to 4 byte */
+	if (spi->use_dma && op->data.nbytes >= ATCSPI_DMA_THRESHOLD)
+		op->data.nbytes = ALIGN_DOWN(op->data.nbytes, 4);
+
+	return 0;
+}
+
+static int atcspi_dma_config(struct atcspi_dev *spi, bool is_rx)
+{
+	struct dma_slave_config conf = { 0 };
+	struct dma_chan *chan;
+
+	if (is_rx) {
+		chan = spi->host->dma_rx;
+		conf.direction = DMA_DEV_TO_MEM;
+		conf.src_addr = spi->dma_addr;
+	} else {
+		chan = spi->host->dma_tx;
+		conf.direction = DMA_MEM_TO_DEV;
+		conf.dst_addr = spi->dma_addr;
+	}
+	conf.dst_maxburst = spi->rxfifo_size / 2;
+	conf.src_maxburst = spi->txfifo_size / 2;
+
+	if (spi->data_merge) {
+		conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+		conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	} else {
+		conf.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+		conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+	}
+
+	return dmaengine_slave_config(chan, &conf);
+}
+
+static void atcspi_dma_callback(void *arg)
+{
+	struct completion *dma_completion = arg;
+
+	complete(dma_completion);
+}
+
+static int atcspi_dma_trans(struct atcspi_dev *spi,
+			    const struct spi_mem_op *op)
+{
+	struct dma_async_tx_descriptor *desc;
+	struct dma_chan *dma_ch;
+	struct sg_table sgt;
+	enum dma_transfer_direction dma_dir;
+	dma_cookie_t cookie;
+	unsigned int ctrl;
+	int timeout;
+	int ret;
+
+	regmap_read(spi->regmap, ATCSPI_CTRL, &ctrl);
+	ctrl |= CTRL_TX_DMA_EN | CTRL_RX_DMA_EN;
+	regmap_write(spi->regmap, ATCSPI_CTRL, ctrl);
+	if (op->data.dir == SPI_MEM_DATA_IN) {
+		ret = atcspi_dma_config(spi, TRUE);
+		dma_dir = DMA_DEV_TO_MEM;
+		dma_ch = spi->host->dma_rx;
+	} else {
+		ret = atcspi_dma_config(spi, FALSE);
+		dma_dir = DMA_MEM_TO_DEV;
+		dma_ch = spi->host->dma_tx;
+	}
+	if (ret)
+		return ret;
+
+	ret = spi_controller_dma_map_mem_op_data(spi->host, op, &sgt);
+	if (ret)
+		return ret;
+
+	desc = dmaengine_prep_slave_sg(dma_ch, sgt.sgl, sgt.nents, dma_dir,
+				       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!desc) {
+		ret = -ENOMEM;
+		goto exit_unmap;
+	}
+
+	reinit_completion(&spi->dma_completion);
+	desc->callback = atcspi_dma_callback;
+	desc->callback_param = &spi->dma_completion;
+	cookie = dmaengine_submit(desc);
+	ret = dma_submit_error(cookie);
+	if (ret)
+		goto exit_unmap;
+
+	dma_async_issue_pending(dma_ch);
+	timeout = msecs_to_jiffies(ATCSPI_XFER_TIMEOUT(op->data.nbytes));
+	if (!wait_for_completion_timeout(&spi->dma_completion, timeout)) {
+		ret = -ETIMEDOUT;
+		dmaengine_terminate_all(dma_ch);
+	}
+
+exit_unmap:
+	spi_controller_dma_unmap_mem_op_data(spi->host, op, &sgt);
+
+	return ret;
+}
+
+static int atcspi_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+	struct spi_device *spi_dev = mem->spi;
+	struct atcspi_dev *spi;
+	unsigned int val;
+	int ret;
+
+	spi = spi_controller_get_devdata(spi_dev->controller);
+	mutex_lock(&spi->mutex_lock);
+	atcspi_prepare_trans(spi, op);
+	if (op->data.nbytes) {
+		if (spi->use_dma && op->data.nbytes >= ATCSPI_DMA_THRESHOLD)
+			ret = atcspi_dma_trans(spi, op);
+		else
+			ret = atcspi_xfer_data_poll(spi, op);
+		if (ret) {
+			dev_info(spi->dev, "SPI transmission failed\n");
+			goto exec_mem_exit;
+		}
+	}
+
+	ret = regmap_read_poll_timeout(spi->regmap,
+				       ATCSPI_STATUS,
+				       val,
+				       !(val & ATCSPI_ACTIVE),
+				       0,
+				       ATCSPI_RDY_TIMEOUT_US);
+	if (ret)
+		dev_info(spi->dev, "Timed out waiting for ATCSPI_ACTIVE\n");
+
+exec_mem_exit:
+	mutex_unlock(&spi->mutex_lock);
+
+	return ret;
+}
+
+static const struct spi_controller_mem_ops atcspi_mem_ops = {
+	.exec_op = atcspi_exec_mem_op,
+	.adjust_op_size = atcspi_adjust_op_size,
+};
+
+static int atcspi_setup(struct atcspi_dev *spi)
+{
+	unsigned int ctrl_val;
+	unsigned int val;
+	int actual_spi_sclk_f;
+	int ret;
+	unsigned char div;
+
+	ctrl_val = CTRL_TX_FIFO_RST | CTRL_RX_FIFO_RST | CTRL_SPI_RST;
+	regmap_write(spi->regmap, ATCSPI_CTRL, ctrl_val);
+	ret = regmap_read_poll_timeout(spi->regmap,
+				       ATCSPI_CTRL,
+				       val,
+				       !(val & ctrl_val),
+				       0,
+				       ATCSPI_RDY_TIMEOUT_US);
+	if (ret)
+		return dev_err_probe(spi->dev, ret,
+				     "Timed out waiting for ATCSPI_CTRL\n");
+
+	val = TRANS_FMT_DATA_LEN(ATCSPI_BITS_PER_UINT) |
+	      TRANS_FMT_CPHA | TRANS_FMT_CPOL;
+	regmap_write(spi->regmap, ATCSPI_TRANS_FMT, val);
+
+	regmap_read(spi->regmap, ATCSPI_CONFIG, &val);
+	spi->txfifo_size = BIT(TXFIFO_SIZE(val) + 1);
+	spi->rxfifo_size = BIT(RXFIFO_SIZE(val) + 1);
+
+	regmap_read(spi->regmap, ATCSPI_TIMING, &val);
+	val &= ~TIMING_SCLK_DIV_MASK;
+
+	/*
+	 * The SCLK_DIV value 0xFF is special and indicates that the
+	 * SCLK rate should be the same as the SPI clock rate.
+	 */
+	if (spi->sclk_rate >= spi->clk_rate) {
+		div = TIMING_SCLK_DIV_MASK;
+	} else {
+		/*
+		 * The divider value is determined as follows:
+		 * 1. If the divider can generate the exact target frequency,
+		 *    use that setting.
+		 * 2. If an exact match is not possible, select the closest
+		 *    available setting that is lower than the target frequency.
+		 */
+		div = (spi->clk_rate + (spi->sclk_rate * 2 - 1)) /
+		      (spi->sclk_rate * 2) - 1;
+
+		/* Check if the actual SPI clock is lower than the target */
+		actual_spi_sclk_f = spi->clk_rate / ((div + 1) * 2);
+		if (actual_spi_sclk_f < spi->sclk_rate)
+			dev_info(spi->dev,
+				 "Clock adjusted %d to %d due to divider limitation",
+				 spi->sclk_rate, actual_spi_sclk_f);
+
+		if (div > TIMING_SCLK_DIV_MAX)
+			return dev_err_probe(spi->dev, -EINVAL,
+					     "Unsupported SPI clock %d\n",
+					     spi->sclk_rate);
+	}
+	val |= div;
+	regmap_write(spi->regmap, ATCSPI_TIMING, val);
+
+	return ret;
+}
+
+static int atcspi_init_resources(struct platform_device *pdev,
+				 struct atcspi_dev *spi,
+				 struct resource **mem_res)
+{
+	void __iomem *base;
+	const struct regmap_config atcspi_regmap_cfg = {
+		.name = "atcspi",
+		.reg_bits = 32,
+		.val_bits = 32,
+		.cache_type = REGCACHE_NONE,
+		.reg_stride = 4,
+		.pad_bits = 0,
+		.max_register = ATCSPI_CONFIG
+	};
+
+	base = devm_platform_get_and_ioremap_resource(pdev, 0, mem_res);
+	if (IS_ERR(base))
+		return dev_err_probe(spi->dev, PTR_ERR(base),
+				     "Failed to get ioremap resource\n");
+
+	spi->regmap = devm_regmap_init_mmio(spi->dev, base,
+					    &atcspi_regmap_cfg);
+	if (IS_ERR(spi->regmap))
+		return dev_err_probe(spi->dev, PTR_ERR(spi->regmap),
+				     "Failed to init regmap\n");
+
+	spi->clk = devm_clk_get(spi->dev, NULL);
+	if (IS_ERR(spi->clk))
+		return dev_err_probe(spi->dev, PTR_ERR(spi->clk),
+				     "Failed to get SPI clock\n");
+
+	spi->sclk_rate = ATCSPI_MAX_SPEED_HZ;
+	return 0;
+}
+
+static struct dma_chan *atcspi_request_dma_chan(struct device *dev,
+						unsigned char *chan_name)
+{
+	struct dma_chan *dma_chan;
+	dma_cap_mask_t mask;
+
+	dma_chan = dma_request_chan(dev, chan_name);
+	if (PTR_ERR(dma_chan) == -ENODEV) {
+		dma_cap_zero(mask);
+		dma_cap_set(DMA_SLAVE, mask);
+		dma_chan = dma_request_channel(mask, NULL, NULL);
+	}
+
+	return dma_chan;
+}
+
+static int atcspi_configure_dma(struct atcspi_dev *spi)
+{
+	struct dma_chan *dma_chan;
+	int ret = 0;
+
+	dma_chan = atcspi_request_dma_chan(spi->dev, "spi_rx");
+	if (IS_ERR(dma_chan)) {
+		ret = PTR_ERR(dma_chan);
+		goto err_exit;
+	}
+	spi->host->dma_rx = dma_chan;
+
+	dma_chan = atcspi_request_dma_chan(spi->dev, "spi_tx");
+	if (IS_ERR(dma_chan)) {
+		ret = PTR_ERR(dma_chan);
+		goto free_rx;
+	}
+	spi->host->dma_tx = dma_chan;
+	init_completion(&spi->dma_completion);
+
+	return ret;
+
+free_rx:
+	dma_release_channel(spi->host->dma_rx);
+	spi->host->dma_rx = NULL;
+err_exit:
+	return ret;
+}
+
+static int atcspi_enable_clk(struct atcspi_dev *spi)
+{
+	int ret;
+
+	ret = clk_prepare_enable(spi->clk);
+	if (ret)
+		return dev_err_probe(spi->dev, ret,
+				     "Failed to enable clock\n");
+
+	spi->clk_rate = clk_get_rate(spi->clk);
+	if (!spi->clk_rate)
+		return dev_err_probe(spi->dev, -EINVAL,
+				     "Failed to get SPI clock rate\n");
+
+	return 0;
+}
+
+static void atcspi_init_controller(struct platform_device *pdev,
+				   struct atcspi_dev *spi,
+				   struct spi_controller *host,
+				   struct resource *mem_res)
+{
+	/* Get the physical address of the data register for DMA transfers. */
+	spi->dma_addr = (dma_addr_t)(mem_res->start + ATCSPI_DATA);
+
+	/* Initialize controller properties */
+	host->bus_num = pdev->id;
+	host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_QUAD | SPI_TX_QUAD;
+	host->dev.of_node = pdev->dev.of_node;
+	host->num_chipselect = ATCSPI_MAX_CS_NUM;
+	host->mem_ops = &atcspi_mem_ops;
+	host->max_speed_hz = spi->sclk_rate;
+}
+
+static int atcspi_probe(struct platform_device *pdev)
+{
+	struct spi_controller *host;
+	struct atcspi_dev *spi;
+	struct resource *mem_res;
+	int ret;
+
+	host = spi_alloc_host(&pdev->dev, sizeof(*spi));
+	if (!host)
+		return -ENOMEM;
+
+	spi = spi_controller_get_devdata(host);
+	spi->host = host;
+	spi->dev = &pdev->dev;
+	platform_set_drvdata(pdev, host);
+
+	ret = atcspi_init_resources(pdev, spi, &mem_res);
+	if (ret)
+		goto free_controller;
+
+	ret = atcspi_enable_clk(spi);
+	if (ret)
+		goto free_controller;
+
+	atcspi_init_controller(pdev, spi, host, mem_res);
+
+	ret = atcspi_setup(spi);
+	if (ret)
+		goto free_controller;
+
+	ret = devm_spi_register_controller(&pdev->dev, host);
+	if (ret) {
+		dev_err_probe(spi->dev, ret,
+			      "Failed to register SPI controller\n");
+		goto free_controller;
+	}
+
+	spi->use_dma = false;
+	if (ATCSPI_DMA_SUPPORT) {
+		ret = atcspi_configure_dma(spi);
+		if (ret)
+			dev_info(spi->dev,
+				 "Failed to init DMA, fallback to PIO mode\n");
+		else
+			spi->use_dma = true;
+	}
+	mutex_init(&spi->mutex_lock);
+
+	return 0;
+
+free_controller:
+	spi_controller_put(host);
+	return ret;
+}
+
+static const struct of_device_id atcspi_of_match[] = {
+	{ .compatible = "andestech,qilai-spi", },
+	{ .compatible = "andestech,atcspi200", },
+	{}
+};
+
+MODULE_DEVICE_TABLE(of, atcspi_of_match);
+
+static struct platform_driver atcspi_driver = {
+	.probe = atcspi_probe,
+	.driver = {
+		.name = "atcspi200",
+		.of_match_table = atcspi_of_match,
+	},
+};
+module_platform_driver(atcspi_driver);
+
+MODULE_AUTHOR("CL Wang <cl634@...estech.com>");
+MODULE_DESCRIPTION("Andes ATCSPI200 SPI controller driver");
+MODULE_LICENSE("GPL");
-- 
2.34.1

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