path: root/target/linux/mediatek/patches/0026-spi-mediatek-Add-spi-bus-for-Mediatek-MT8173.patch

From 047222cfefe97ef8706f03117bc8deada4cb4ddd Mon Sep 17 00:00:00 2001
From: Leilk Liu <leilk.liu@mediatek.com>
Date: Fri, 8 May 2015 16:55:42 +0800
Subject: [PATCH 26/76] spi: mediatek: Add spi bus for Mediatek MT8173

This patch adds basic spi bus for MT8173.

Signed-off-by: Leilk Liu <leilk.liu@mediatek.com>
---
 drivers/spi/Kconfig      |   10 +
 drivers/spi/Makefile     |    1 +
 drivers/spi/spi-mt65xx.c |  622 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 633 insertions(+)
 create mode 100644 drivers/spi/spi-mt65xx.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 72b0590..53dbea3 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -325,6 +325,16 @@ config SPI_MESON_SPIFC
 	  This enables master mode support for the SPIFC (SPI flash
 	  controller) available in Amlogic Meson SoCs.
 
+config SPI_MT65XX
+	tristate "MediaTek SPI controller"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	select SPI_BITBANG
+	help
+	  This selects the MediaTek(R) SPI bus driver.
+	  If you want to use MediaTek(R) SPI interface,
+	  say Y or M here.If you are not sure, say N.
+	  SPI drivers for Mediatek mt65XX series ARM SoCs.
+
 config SPI_OC_TINY
 	tristate "OpenCores tiny SPI"
 	depends on GPIOLIB
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index d8cbf65..ab332ef 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_SPI_MESON_SPIFC)		+= spi-meson-spifc.o
 obj-$(CONFIG_SPI_MPC512x_PSC)		+= spi-mpc512x-psc.o
 obj-$(CONFIG_SPI_MPC52xx_PSC)		+= spi-mpc52xx-psc.o
 obj-$(CONFIG_SPI_MPC52xx)		+= spi-mpc52xx.o
+obj-$(CONFIG_SPI_MT65XX)                += spi-mt65xx.o
 obj-$(CONFIG_SPI_MXS)			+= spi-mxs.o
 obj-$(CONFIG_SPI_NUC900)		+= spi-nuc900.o
 obj-$(CONFIG_SPI_OC_TINY)		+= spi-oc-tiny.o
diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
new file mode 100644
index 0000000..92c119d
--- /dev/null
+++ b/drivers/spi/spi-mt65xx.c
@@ -0,0 +1,622 @@
+/*
+ * Copyright (c) 2015 MediaTek Inc.
+ * Author: Leilk Liu <leilk.liu@mediatek.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/ioport.h>
+#include <linux/errno.h>
+#include <linux/spi/spi.h>
+#include <linux/workqueue.h>
+#include <linux/dma-mapping.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/sched.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/kernel.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/gpio.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+
+#define SPI_CFG0_REG                      0x0000
+#define SPI_CFG1_REG                      0x0004
+#define SPI_TX_SRC_REG                    0x0008
+#define SPI_RX_DST_REG                    0x000c
+#define SPI_CMD_REG                       0x0018
+#define SPI_STATUS0_REG                   0x001c
+#define SPI_PAD_SEL_REG                   0x0024
+
+#define SPI_CFG0_SCK_HIGH_OFFSET          0
+#define SPI_CFG0_SCK_LOW_OFFSET           8
+#define SPI_CFG0_CS_HOLD_OFFSET           16
+#define SPI_CFG0_CS_SETUP_OFFSET          24
+
+#define SPI_CFG0_SCK_HIGH_MASK            0xff
+#define SPI_CFG0_SCK_LOW_MASK             0xff00
+#define SPI_CFG0_CS_HOLD_MASK             0xff0000
+#define SPI_CFG0_CS_SETUP_MASK            0xff000000
+
+#define SPI_CFG1_CS_IDLE_OFFSET           0
+#define SPI_CFG1_PACKET_LOOP_OFFSET       8
+#define SPI_CFG1_PACKET_LENGTH_OFFSET     16
+#define SPI_CFG1_GET_TICK_DLY_OFFSET      30
+
+#define SPI_CFG1_CS_IDLE_MASK             0xff
+#define SPI_CFG1_PACKET_LOOP_MASK         0xff00
+#define SPI_CFG1_PACKET_LENGTH_MASK       0x3ff0000
+#define SPI_CFG1_GET_TICK_DLY_MASK        0xc0000000
+
+#define SPI_CMD_ACT_OFFSET                0
+#define SPI_CMD_RESUME_OFFSET             1
+#define SPI_CMD_RST_OFFSET                2
+#define SPI_CMD_PAUSE_EN_OFFSET           4
+#define SPI_CMD_DEASSERT_OFFSET           5
+#define SPI_CMD_CPHA_OFFSET               8
+#define SPI_CMD_CPOL_OFFSET               9
+#define SPI_CMD_RX_DMA_OFFSET             10
+#define SPI_CMD_TX_DMA_OFFSET             11
+#define SPI_CMD_TXMSBF_OFFSET             12
+#define SPI_CMD_RXMSBF_OFFSET             13
+#define SPI_CMD_RX_ENDIAN_OFFSET          14
+#define SPI_CMD_TX_ENDIAN_OFFSET          15
+#define SPI_CMD_FINISH_IE_OFFSET          16
+#define SPI_CMD_PAUSE_IE_OFFSET           17
+
+#define SPI_CMD_RESUME_MASK               0x2
+#define SPI_CMD_RST_MASK                  0x4
+#define SPI_CMD_PAUSE_EN_MASK             0x10
+#define SPI_CMD_DEASSERT_MASK             0x20
+#define SPI_CMD_CPHA_MASK                 0x100
+#define SPI_CMD_CPOL_MASK                 0x200
+#define SPI_CMD_RX_DMA_MASK               0x400
+#define SPI_CMD_TX_DMA_MASK               0x800
+#define SPI_CMD_TXMSBF_MASK               0x1000
+#define SPI_CMD_RXMSBF_MASK               0x2000
+#define SPI_CMD_RX_ENDIAN_MASK            0x4000
+#define SPI_CMD_TX_ENDIAN_MASK            0x8000
+#define SPI_CMD_FINISH_IE_MASK            0x10000
+
+#define COMPAT_MT6589			(0x1 << 0)
+#define COMPAT_MT8173			(0x1 << 1)
+
+#define MT8173_MAX_PAD_SEL 3
+
+#define IDLE 0
+#define INPROGRESS 1
+#define PAUSED 2
+
+#define PACKET_SIZE 1024
+
+struct mtk_chip_config {
+	u32 setuptime;
+	u32 holdtime;
+	u32 high_time;
+	u32 low_time;
+	u32 cs_idletime;
+	u32 tx_mlsb;
+	u32 rx_mlsb;
+	u32 tx_endian;
+	u32 rx_endian;
+	u32 pause;
+	u32 finish_intr;
+	u32 deassert;
+	u32 tckdly;
+};
+
+struct mtk_spi_ddata {
+	struct spi_bitbang bitbang;
+	void __iomem *base;
+	u32 irq;
+	u32 state;
+	u32 platform_compat;
+	u32 pad_sel;
+	struct clk *clk;
+
+	const u8 *tx_buf;
+	u8 *rx_buf;
+	u32 tx_len, rx_len;
+	struct completion done;
+};
+
+/*
+ * A piece of default chip info unless the platform
+ * supplies it.
+ */
+static const struct mtk_chip_config mtk_default_chip_info = {
+	.setuptime = 10,
+	.holdtime = 12,
+	.high_time = 6,
+	.low_time = 6,
+	.cs_idletime = 12,
+	.rx_mlsb = 1,
+	.tx_mlsb = 1,
+	.tx_endian = 0,
+	.rx_endian = 0,
+	.pause = 0,
+	.finish_intr = 1,
+	.deassert = 0,
+	.tckdly = 0,
+};
+
+static const struct of_device_id mtk_spi_of_match[] = {
+	{ .compatible = "mediatek,mt6589-spi", .data = (void *)COMPAT_MT6589},
+	{ .compatible = "mediatek,mt8173-spi", .data = (void *)COMPAT_MT8173},
+	{}
+};
+MODULE_DEVICE_TABLE(of, mtk_spi_of_match);
+
+static void mtk_spi_reset(struct mtk_spi_ddata *mdata)
+{
+	u32 reg_val;
+
+	/*set the software reset bit in SPI_CMD_REG.*/
+	reg_val = readl(mdata->base + SPI_CMD_REG);
+	reg_val &= ~SPI_CMD_RST_MASK;
+	reg_val |= 1 << SPI_CMD_RST_OFFSET;
+	writel(reg_val, mdata->base + SPI_CMD_REG);
+	reg_val = readl(mdata->base + SPI_CMD_REG);
+	reg_val &= ~SPI_CMD_RST_MASK;
+	writel(reg_val, mdata->base + SPI_CMD_REG);
+}
+
+static void mtk_set_pause_bit(struct mtk_spi_ddata *mdata)
+{
+	u32 reg_val;
+
+	reg_val = readl(mdata->base + SPI_CMD_REG);
+	reg_val |= 1 << SPI_CMD_PAUSE_EN_OFFSET;
+	reg_val |= 1 << SPI_CMD_PAUSE_IE_OFFSET;
+	writel(reg_val, mdata->base + SPI_CMD_REG);
+}
+
+static void mtk_clear_pause_bit(struct mtk_spi_ddata *mdata)
+{
+	u32 reg_val;
+
+	reg_val = readl(mdata->base + SPI_CMD_REG);
+	reg_val &= ~SPI_CMD_PAUSE_EN_MASK;
+	writel(reg_val, mdata->base + SPI_CMD_REG);
+}
+
+static int mtk_spi_config(struct mtk_spi_ddata *mdata,
+			  struct mtk_chip_config *chip_config)
+{
+	u32 reg_val;
+
+	/* set the timing */
+	reg_val = readl(mdata->base + SPI_CFG0_REG);
+	reg_val &= ~(SPI_CFG0_SCK_HIGH_MASK | SPI_CFG0_SCK_LOW_MASK);
+	reg_val &= ~(SPI_CFG0_CS_HOLD_MASK | SPI_CFG0_CS_SETUP_MASK);
+	reg_val |= ((chip_config->high_time - 1) << SPI_CFG0_SCK_HIGH_OFFSET);
+	reg_val |= ((chip_config->low_time - 1) << SPI_CFG0_SCK_LOW_OFFSET);
+	reg_val |= ((chip_config->holdtime - 1) << SPI_CFG0_CS_HOLD_OFFSET);
+	reg_val |= ((chip_config->setuptime - 1) << SPI_CFG0_CS_SETUP_OFFSET);
+	writel(reg_val, mdata->base + SPI_CFG0_REG);
+
+	reg_val = readl(mdata->base + SPI_CFG1_REG);
+	reg_val &= ~SPI_CFG1_CS_IDLE_MASK;
+	reg_val |= ((chip_config->cs_idletime - 1) << SPI_CFG1_CS_IDLE_OFFSET);
+	reg_val &= ~SPI_CFG1_GET_TICK_DLY_MASK;
+	reg_val |= ((chip_config->tckdly) << SPI_CFG1_GET_TICK_DLY_OFFSET);
+	writel(reg_val, mdata->base + SPI_CFG1_REG);
+
+	/* set the mlsbx and mlsbtx */
+	reg_val = readl(mdata->base + SPI_CMD_REG);
+	reg_val &= ~(SPI_CMD_TX_ENDIAN_MASK | SPI_CMD_RX_ENDIAN_MASK);
+	reg_val &= ~(SPI_CMD_TXMSBF_MASK | SPI_CMD_RXMSBF_MASK);
+	reg_val |= (chip_config->tx_mlsb << SPI_CMD_TXMSBF_OFFSET);
+	reg_val |= (chip_config->rx_mlsb << SPI_CMD_RXMSBF_OFFSET);
+	reg_val |= (chip_config->tx_endian << SPI_CMD_TX_ENDIAN_OFFSET);
+	reg_val |= (chip_config->rx_endian << SPI_CMD_RX_ENDIAN_OFFSET);
+	writel(reg_val, mdata->base + SPI_CMD_REG);
+
+	/* set finish and pause interrupt always enable */
+	reg_val = readl(mdata->base + SPI_CMD_REG);
+	reg_val &= ~SPI_CMD_FINISH_IE_MASK;
+	reg_val |= (chip_config->finish_intr << SPI_CMD_FINISH_IE_OFFSET);
+	writel(reg_val, mdata->base + SPI_CMD_REG);
+
+	reg_val = readl(mdata->base + SPI_CMD_REG);
+	reg_val |= 1 << SPI_CMD_TX_DMA_OFFSET;
+	reg_val |= 1 << SPI_CMD_RX_DMA_OFFSET;
+	writel(reg_val, mdata->base + SPI_CMD_REG);
+
+	/* set deassert mode */
+	reg_val = readl(mdata->base + SPI_CMD_REG);
+	reg_val &= ~SPI_CMD_DEASSERT_MASK;
+	reg_val |= (chip_config->deassert << SPI_CMD_DEASSERT_OFFSET);
+	writel(reg_val, mdata->base + SPI_CMD_REG);
+
+	/* pad select */
+	if (mdata->platform_compat & COMPAT_MT8173)
+		writel(mdata->pad_sel, mdata->base + SPI_PAD_SEL_REG);
+
+	return 0;
+}
+
+static int mtk_spi_setup_transfer(struct spi_device *spi,
+				  struct spi_transfer *t)
+{
+	u32 reg_val;
+	struct spi_master *master = spi->master;
+	struct mtk_spi_ddata *mdata = spi_master_get_devdata(master);
+	struct spi_message *m = master->cur_msg;
+	struct mtk_chip_config *chip_config;
+
+	u8 cpha	= spi->mode & SPI_CPHA ? 1 : 0;
+	u8 cpol = spi->mode & SPI_CPOL ? 1 : 0;
+
+	reg_val = readl(mdata->base + SPI_CMD_REG);
+	reg_val &= ~(SPI_CMD_CPHA_MASK | SPI_CMD_CPOL_MASK);
+	reg_val |= (cpha << SPI_CMD_CPHA_OFFSET);
+	reg_val |= (cpol << SPI_CMD_CPOL_OFFSET);
+	writel(reg_val, mdata->base + SPI_CMD_REG);
+
+	if (t->cs_change) {
+		if (!(list_is_last(&t->transfer_list, &m->transfers)))
+			mdata->state = IDLE;
+	} else {
+		mdata->state = IDLE;
+		mtk_spi_reset(mdata);
+	}
+
+	chip_config = (struct mtk_chip_config *)spi->controller_data;
+	if (!chip_config) {
+		chip_config = (void *)&mtk_default_chip_info;
+		spi->controller_data = chip_config;
+		mdata->state = IDLE;
+	}
+
+	mtk_spi_config(mdata, chip_config);
+
+	return 0;
+}
+
+static void mtk_spi_chipselect(struct spi_device *spi, int is_on)
+{
+	struct mtk_spi_ddata *mdata = spi_master_get_devdata(spi->master);
+
+	switch (is_on) {
+	case BITBANG_CS_ACTIVE:
+		mtk_set_pause_bit(mdata);
+		break;
+	case BITBANG_CS_INACTIVE:
+		mtk_clear_pause_bit(mdata);
+		break;
+	}
+}
+
+static void mtk_spi_start_transfer(struct mtk_spi_ddata *mdata)
+{
+	u32 reg_val;
+
+	reg_val = readl(mdata->base + SPI_CMD_REG);
+	reg_val |= 1 << SPI_CMD_ACT_OFFSET;
+	writel(reg_val, mdata->base + SPI_CMD_REG);
+}
+
+static void mtk_spi_resume_transfer(struct mtk_spi_ddata *mdata)
+{
+	u32 reg_val;
+
+	reg_val = readl(mdata->base + SPI_CMD_REG);
+	reg_val &= ~SPI_CMD_RESUME_MASK;
+	reg_val |= 1 << SPI_CMD_RESUME_OFFSET;
+	writel(reg_val, mdata->base + SPI_CMD_REG);
+}
+
+static int mtk_spi_setup_packet(struct mtk_spi_ddata *mdata,
+				struct spi_transfer *xfer)
+{
+	struct device *dev = &mdata->bitbang.master->dev;
+	u32 packet_size, packet_loop, reg_val;
+
+	packet_size = min_t(unsigned, xfer->len, PACKET_SIZE);
+
+	/* mtk hw has the restriction that xfer len must be a multiple of 1024,
+	 * when it is greater than 1024bytes.
+	 */
+	if (xfer->len % packet_size) {
+		dev_err(dev, "ERROR!The lens must be a multiple of %d, your len %d\n",
+			PACKET_SIZE, xfer->len);
+		return -EINVAL;
+	}
+
+	packet_loop = xfer->len / packet_size;
+
+	reg_val = readl(mdata->base + SPI_CFG1_REG);
+	reg_val &= ~(SPI_CFG1_PACKET_LENGTH_MASK + SPI_CFG1_PACKET_LOOP_MASK);
+	reg_val |= (packet_size - 1) << SPI_CFG1_PACKET_LENGTH_OFFSET;
+	reg_val |= (packet_loop - 1) << SPI_CFG1_PACKET_LOOP_OFFSET;
+	writel(reg_val, mdata->base + SPI_CFG1_REG);
+
+	return 0;
+}
+
+static int mtk_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *xfer)
+{
+	struct spi_master *master = spi->master;
+	struct mtk_spi_ddata *mdata = spi_master_get_devdata(master);
+	struct device *dev = &mdata->bitbang.master->dev;
+	int cmd, ret;
+
+	/* mtk spi hw tx/rx have 4bytes aligned restriction,
+	 * so kmalloc tx/rx buffer to workaround here.
+	 */
+	mdata->tx_buf = NULL;
+	mdata->rx_buf = NULL;
+	if (xfer->tx_buf) {
+		mdata->tx_buf = kmalloc(xfer->len, GFP_KERNEL);
+		if (!mdata->tx_buf) {
+			dev_err(dev, "malloc tx_buf failed.\n");
+			ret = -ENOMEM;
+			goto err_free;
+		}
+		memcpy((void *)mdata->tx_buf, xfer->tx_buf, xfer->len);
+	}
+	if (xfer->rx_buf) {
+		mdata->rx_buf = kmalloc(xfer->len, GFP_KERNEL);
+		if (!mdata->rx_buf) {
+			dev_err(dev, "malloc rx_buf failed.\n");
+			ret = -ENOMEM;
+			goto err_free;
+		}
+	}
+
+	reinit_completion(&mdata->done);
+
+	xfer->tx_dma = DMA_ERROR_CODE;
+	xfer->rx_dma = DMA_ERROR_CODE;
+	if (xfer->tx_buf) {
+		xfer->tx_dma = dma_map_single(dev, (void *)mdata->tx_buf,
+					      xfer->len, DMA_TO_DEVICE);
+		if (dma_mapping_error(dev, xfer->tx_dma)) {
+			dev_err(dev, "dma mapping tx_buf error.\n");
+			ret = -ENOMEM;
+			goto err_free;
+		}
+	}
+	if (xfer->rx_buf) {
+		xfer->rx_dma = dma_map_single(dev, mdata->rx_buf,
+					      xfer->len, DMA_FROM_DEVICE);
+		if (dma_mapping_error(dev, xfer->rx_dma)) {
+			if (xfer->tx_buf)
+				dma_unmap_single(dev, xfer->tx_dma,
+						 xfer->len, DMA_TO_DEVICE);
+			dev_err(dev, "dma mapping rx_buf error.\n");
+			ret = -ENOMEM;
+			goto err_free;
+		}
+	}
+
+	ret = mtk_spi_setup_packet(mdata, xfer);
+	if (ret != 0)
+		goto err_free;
+
+	/* Here is mt8173 HW issue: RX must enable TX, then TX transfer
+	 * dummy data; TX don't need to enable RX. so enable TX dma for
+	 * RX to workaround.
+	 */
+	cmd = readl(mdata->base + SPI_CMD_REG);
+	if (xfer->tx_buf || (mdata->platform_compat & COMPAT_MT8173))
+		cmd |= 1 << SPI_CMD_TX_DMA_OFFSET;
+	if (xfer->rx_buf)
+		cmd |= 1 << SPI_CMD_RX_DMA_OFFSET;
+	writel(cmd, mdata->base + SPI_CMD_REG);
+
+	/* set up the DMA bus address */
+	if (xfer->tx_dma != DMA_ERROR_CODE)
+		writel(cpu_to_le32(xfer->tx_dma), mdata->base + SPI_TX_SRC_REG);
+	if (xfer->rx_dma != DMA_ERROR_CODE)
+		writel(cpu_to_le32(xfer->rx_dma), mdata->base + SPI_RX_DST_REG);
+
+	if (mdata->state == IDLE)
+		mtk_spi_start_transfer(mdata);
+	else if (mdata->state == PAUSED)
+		mtk_spi_resume_transfer(mdata);
+	else
+		mdata->state = INPROGRESS;
+
+	wait_for_completion(&mdata->done);
+
+	if (xfer->tx_dma != DMA_ERROR_CODE) {
+		dma_unmap_single(dev, xfer->tx_dma, xfer->len, DMA_TO_DEVICE);
+		xfer->tx_dma = DMA_ERROR_CODE;
+	}
+	if (xfer->rx_dma != DMA_ERROR_CODE) {
+		dma_unmap_single(dev, xfer->rx_dma, xfer->len, DMA_FROM_DEVICE);
+		xfer->rx_dma = DMA_ERROR_CODE;
+	}
+
+	/* spi disable dma */
+	cmd = readl(mdata->base + SPI_CMD_REG);
+	cmd &= ~SPI_CMD_TX_DMA_MASK;
+	cmd &= ~SPI_CMD_RX_DMA_MASK;
+	writel(cmd, mdata->base + SPI_CMD_REG);
+
+	if (xfer->rx_buf)
+		memcpy(xfer->rx_buf, mdata->rx_buf, xfer->len);
+
+	ret = xfer->len;
+
+err_free:
+	kfree(mdata->tx_buf);
+	kfree(mdata->rx_buf);
+	return ret;
+}
+
+static irqreturn_t mtk_spi_interrupt(int irq, void *dev_id)
+{
+	struct mtk_spi_ddata *mdata = dev_id;
+	u32 reg_val;
+
+	reg_val = readl(mdata->base + SPI_STATUS0_REG);
+	if (reg_val & 0x2)
+		mdata->state = PAUSED;
+	else
+		mdata->state = IDLE;
+	complete(&mdata->done);
+
+	return IRQ_HANDLED;
+}
+
+static unsigned long mtk_get_device_prop(struct platform_device *pdev)
+{
+	const struct of_device_id *match;
+
+	match = of_match_node(mtk_spi_of_match, pdev->dev.of_node);
+	return (unsigned long)match->data;
+}
+
+static int mtk_spi_probe(struct platform_device *pdev)
+{
+	struct spi_master *master;
+	struct mtk_spi_ddata *mdata;
+	struct resource *res;
+	int	ret;
+
+	master = spi_alloc_master(&pdev->dev, sizeof(struct mtk_spi_ddata));
+	if (!master) {
+		dev_err(&pdev->dev, "failed to alloc spi master\n");
+		return -ENOMEM;
+	}
+
+	platform_set_drvdata(pdev, master);
+
+	master->dev.of_node = pdev->dev.of_node;
+	master->bus_num = pdev->id;
+	master->num_chipselect = 1;
+	master->mode_bits = SPI_CPOL | SPI_CPHA;
+
+	mdata = spi_master_get_devdata(master);
+
+	mdata->bitbang.master = master;
+	mdata->bitbang.chipselect = mtk_spi_chipselect;
+	mdata->bitbang.setup_transfer = mtk_spi_setup_transfer;
+	mdata->bitbang.txrx_bufs = mtk_spi_txrx_bufs;
+	mdata->platform_compat = mtk_get_device_prop(pdev);
+
+	if (mdata->platform_compat & COMPAT_MT8173) {
+		ret = of_property_read_u32(pdev->dev.of_node, "pad-select",
+					   &mdata->pad_sel);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to read pad select: %d\n",
+				ret);
+			goto err;
+		}
+
+		if (mdata->pad_sel > MT8173_MAX_PAD_SEL) {
+			dev_err(&pdev->dev, "wrong pad-select: %u\n",
+				mdata->pad_sel);
+			goto err;
+		}
+	}
+
+	init_completion(&mdata->done);
+
+	mdata->clk = devm_clk_get(&pdev->dev, "main");
+	if (IS_ERR(mdata->clk)) {
+		ret = PTR_ERR(mdata->clk);
+		dev_err(&pdev->dev, "failed to get clock: %d\n", ret);
+		goto err;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = -ENODEV;
+		dev_err(&pdev->dev, "failed to determine base address\n");
+		goto err;
+	}
+
+	mdata->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(mdata->base)) {
+		ret = PTR_ERR(mdata->base);
+		goto err;
+	}
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to get irq (%d)\n", ret);
+		goto err;
+	}
+
+	mdata->irq = ret;
+
+	if (!pdev->dev.dma_mask)
+		pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
+
+	mdata->bitbang.master->dev.dma_mask = pdev->dev.dma_mask;
+
+	ret = clk_prepare_enable(mdata->clk);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to enable clock (%d)\n", ret);
+		goto err;
+	}
+
+	ret = devm_request_irq(&pdev->dev, mdata->irq, mtk_spi_interrupt,
+			       IRQF_TRIGGER_NONE, dev_name(&pdev->dev), mdata);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register irq (%d)\n", ret);
+		goto err_disable_clk;
+	}
+
+	ret = spi_bitbang_start(&mdata->bitbang);
+	if (ret) {
+		dev_err(&pdev->dev, "spi_bitbang_start failed (%d)\n", ret);
+err_disable_clk:
+		clk_disable_unprepare(mdata->clk);
+err:
+		spi_master_put(master);
+	}
+
+	return ret;
+}
+
+static int mtk_spi_remove(struct platform_device *pdev)
+{
+	struct spi_master *master = platform_get_drvdata(pdev);
+	struct mtk_spi_ddata *mdata = spi_master_get_devdata(master);
+
+	spi_bitbang_stop(&mdata->bitbang);
+	mtk_spi_reset(mdata);
+	clk_disable_unprepare(mdata->clk);
+	spi_master_put(master);
+
+	return 0;
+}
+
+struct platform_driver mtk_spi_driver = {
+	.driver = {
+		.name = "mtk-spi",
+		.of_match_table = mtk_spi_of_match,
+	},
+	.probe = mtk_spi_probe,
+	.remove = mtk_spi_remove,
+};
+
+module_platform_driver(mtk_spi_driver);
+
+MODULE_DESCRIPTION("MTK SPI Controller driver");
+MODULE_AUTHOR("Leilk Liu <leilk.liu@mediatek.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform: mtk_spi");
-- 
1.7.10.4