spi/tegra114: add spi driver

Add SPI driver for NVIDIA's Tegra114 SPI controller. This controller
is different than the older SoCs SPI controller in internal design as
well as register interface.

This driver supports the:
- non DMA based transfer for smaller transfer i.e. less than FIFO depth.
- APB DMA based transfer for larger transfer i.e. more than FIFO depth.
- Clock gating through runtime PM callbacks.
- registration through DT only.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

Documentation/devicetree/bindings/spi/nvidia,tegra114-spi.txt

+NVIDIA Tegra114 SPI controller.
+
+Required properties:
+- compatible : should be "nvidia,tegra114-spi".
+- reg: Should contain SPI registers location and length.
+- interrupts: Should contain SPI interrupts.
+- nvidia,dma-request-selector : The Tegra DMA controller's phandle and
+  request selector for this SPI controller.
+- This is also require clock named "spi" as per binding document
+  Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Recommended properties:
+- spi-max-frequency: Definition as per
+                     Documentation/devicetree/bindings/spi/spi-bus.txt
+Example:
+
+spi@7000d600 {
+	compatible = "nvidia,tegra114-spi";
+	reg = <0x7000d600 0x200>;
+	interrupts = <0 82 0x04>;
+	nvidia,dma-request-selector = <&apbdma 16>;
+	spi-max-frequency = <25000000>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+	status = "disabled";
+};

drivers/spi/Kconfig

@@ -415,6 +415,14 @@ config SPI_MXS
 	help
 	  SPI driver for Freescale MXS devices.
 
+config SPI_TEGRA114
+	tristate "NVIDIA Tegra114 SPI Controller"
+	depends on ARCH_TEGRA && TEGRA20_APB_DMA
+	help
+	  SPI driver for NVIDIA Tegra114 SPI Controller interface. This controller
+	  is different than the older SoCs SPI controller and also register interface
+	  get changed with this controller.
+
 config SPI_TEGRA20_SFLASH
 	tristate "Nvidia Tegra20 Serial flash Controller"
 	depends on ARCH_TEGRA

drivers/spi/Makefile

@@ -65,6 +65,7 @@ obj-$(CONFIG_SPI_SH_HSPI)		+= spi-sh-hspi.o
 obj-$(CONFIG_SPI_SH_MSIOF)		+= spi-sh-msiof.o
 obj-$(CONFIG_SPI_SH_SCI)		+= spi-sh-sci.o
 obj-$(CONFIG_SPI_SIRF)		+= spi-sirf.o
+obj-$(CONFIG_SPI_TEGRA114)		+= spi-tegra114.o
 obj-$(CONFIG_SPI_TEGRA20_SFLASH)	+= spi-tegra20-sflash.o
 obj-$(CONFIG_SPI_TEGRA20_SLINK)		+= spi-tegra20-slink.o
 obj-$(CONFIG_SPI_TI_SSP)		+= spi-ti-ssp.o

drivers/spi/spi-tegra114.c

+/*
+ * SPI driver for NVIDIA's Tegra114 SPI Controller.
+ *
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/clk.h>
+#include <linux/clk/tegra.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/spi/spi.h>
+
+#define SPI_COMMAND1				0x000
+#define SPI_BIT_LENGTH(x)			(((x) & 0x1f) << 0)
+#define SPI_PACKED				(1 << 5)
+#define SPI_TX_EN				(1 << 11)
+#define SPI_RX_EN				(1 << 12)
+#define SPI_BOTH_EN_BYTE			(1 << 13)
+#define SPI_BOTH_EN_BIT				(1 << 14)
+#define SPI_LSBYTE_FE				(1 << 15)
+#define SPI_LSBIT_FE				(1 << 16)
+#define SPI_BIDIROE				(1 << 17)
+#define SPI_IDLE_SDA_DRIVE_LOW			(0 << 18)
+#define SPI_IDLE_SDA_DRIVE_HIGH			(1 << 18)
+#define SPI_IDLE_SDA_PULL_LOW			(2 << 18)
+#define SPI_IDLE_SDA_PULL_HIGH			(3 << 18)
+#define SPI_IDLE_SDA_MASK			(3 << 18)
+#define SPI_CS_SS_VAL				(1 << 20)
+#define SPI_CS_SW_HW				(1 << 21)
+/* SPI_CS_POL_INACTIVE bits are default high */
+#define SPI_CS_POL_INACTIVE			22
+#define SPI_CS_POL_INACTIVE_0			(1 << 22)
+#define SPI_CS_POL_INACTIVE_1			(1 << 23)
+#define SPI_CS_POL_INACTIVE_2			(1 << 24)
+#define SPI_CS_POL_INACTIVE_3			(1 << 25)
+#define SPI_CS_POL_INACTIVE_MASK		(0xF << 22)
+
+#define SPI_CS_SEL_0				(0 << 26)
+#define SPI_CS_SEL_1				(1 << 26)
+#define SPI_CS_SEL_2				(2 << 26)
+#define SPI_CS_SEL_3				(3 << 26)
+#define SPI_CS_SEL_MASK				(3 << 26)
+#define SPI_CS_SEL(x)				(((x) & 0x3) << 26)
+#define SPI_CONTROL_MODE_0			(0 << 28)
+#define SPI_CONTROL_MODE_1			(1 << 28)
+#define SPI_CONTROL_MODE_2			(2 << 28)
+#define SPI_CONTROL_MODE_3			(3 << 28)
+#define SPI_CONTROL_MODE_MASK			(3 << 28)
+#define SPI_MODE_SEL(x)				(((x) & 0x3) << 28)
+#define SPI_M_S					(1 << 30)
+#define SPI_PIO					(1 << 31)
+
+#define SPI_COMMAND2				0x004
+#define SPI_TX_TAP_DELAY(x)			(((x) & 0x3F) << 6)
+#define SPI_RX_TAP_DELAY(x)			(((x) & 0x3F) << 0)
+
+#define SPI_CS_TIMING1				0x008
+#define SPI_SETUP_HOLD(setup, hold)		(((setup) << 4) | (hold))
+#define SPI_CS_SETUP_HOLD(reg, cs, val)			\
+		((((val) & 0xFFu) << ((cs) * 8)) |	\
+		((reg) & ~(0xFFu << ((cs) * 8))))
+
+#define SPI_CS_TIMING2				0x00C
+#define CYCLES_BETWEEN_PACKETS_0(x)		(((x) & 0x1F) << 0)
+#define CS_ACTIVE_BETWEEN_PACKETS_0		(1 << 5)
+#define CYCLES_BETWEEN_PACKETS_1(x)		(((x) & 0x1F) << 8)
+#define CS_ACTIVE_BETWEEN_PACKETS_1		(1 << 13)
+#define CYCLES_BETWEEN_PACKETS_2(x)		(((x) & 0x1F) << 16)
+#define CS_ACTIVE_BETWEEN_PACKETS_2		(1 << 21)
+#define CYCLES_BETWEEN_PACKETS_3(x)		(((x) & 0x1F) << 24)
+#define CS_ACTIVE_BETWEEN_PACKETS_3		(1 << 29)
+#define SPI_SET_CS_ACTIVE_BETWEEN_PACKETS(reg, cs, val)		\
+		(reg = (((val) & 0x1) << ((cs) * 8 + 5)) |	\
+			((reg) & ~(1 << ((cs) * 8 + 5))))
+#define SPI_SET_CYCLES_BETWEEN_PACKETS(reg, cs, val)		\
+		(reg = (((val) & 0xF) << ((cs) * 8)) |		\
+			((reg) & ~(0xF << ((cs) * 8))))
+
+#define SPI_TRANS_STATUS			0x010
+#define SPI_BLK_CNT(val)			(((val) >> 0) & 0xFFFF)
+#define SPI_SLV_IDLE_COUNT(val)			(((val) >> 16) & 0xFF)
+#define SPI_RDY					(1 << 30)
+
+#define SPI_FIFO_STATUS				0x014
+#define SPI_RX_FIFO_EMPTY			(1 << 0)
+#define SPI_RX_FIFO_FULL			(1 << 1)
+#define SPI_TX_FIFO_EMPTY			(1 << 2)
+#define SPI_TX_FIFO_FULL			(1 << 3)
+#define SPI_RX_FIFO_UNF				(1 << 4)
+#define SPI_RX_FIFO_OVF				(1 << 5)
+#define SPI_TX_FIFO_UNF				(1 << 6)
+#define SPI_TX_FIFO_OVF				(1 << 7)
+#define SPI_ERR					(1 << 8)
+#define SPI_TX_FIFO_FLUSH			(1 << 14)
+#define SPI_RX_FIFO_FLUSH			(1 << 15)
+#define SPI_TX_FIFO_EMPTY_COUNT(val)		(((val) >> 16) & 0x7F)
+#define SPI_RX_FIFO_FULL_COUNT(val)		(((val) >> 23) & 0x7F)
+#define SPI_FRAME_END				(1 << 30)
+#define SPI_CS_INACTIVE				(1 << 31)
+
+#define SPI_FIFO_ERROR				(SPI_RX_FIFO_UNF | \
+			SPI_RX_FIFO_OVF | SPI_TX_FIFO_UNF | SPI_TX_FIFO_OVF)
+#define SPI_FIFO_EMPTY			(SPI_RX_FIFO_EMPTY | SPI_TX_FIFO_EMPTY)
+
+#define SPI_TX_DATA				0x018
+#define SPI_RX_DATA				0x01C
+
+#define SPI_DMA_CTL				0x020
+#define SPI_TX_TRIG_1				(0 << 15)
+#define SPI_TX_TRIG_4				(1 << 15)
+#define SPI_TX_TRIG_8				(2 << 15)
+#define SPI_TX_TRIG_16				(3 << 15)
+#define SPI_TX_TRIG_MASK			(3 << 15)
+#define SPI_RX_TRIG_1				(0 << 19)
+#define SPI_RX_TRIG_4				(1 << 19)
+#define SPI_RX_TRIG_8				(2 << 19)
+#define SPI_RX_TRIG_16				(3 << 19)
+#define SPI_RX_TRIG_MASK			(3 << 19)
+#define SPI_IE_TX				(1 << 28)
+#define SPI_IE_RX				(1 << 29)
+#define SPI_CONT				(1 << 30)
+#define SPI_DMA					(1 << 31)
+#define SPI_DMA_EN				SPI_DMA
+
+#define SPI_DMA_BLK				0x024
+#define SPI_DMA_BLK_SET(x)			(((x) & 0xFFFF) << 0)
+
+#define SPI_TX_FIFO				0x108
+#define SPI_RX_FIFO				0x188
+#define MAX_CHIP_SELECT				4
+#define SPI_FIFO_DEPTH				64
+#define DATA_DIR_TX				(1 << 0)
+#define DATA_DIR_RX				(1 << 1)
+
+#define SPI_DMA_TIMEOUT				(msecs_to_jiffies(1000))
+#define DEFAULT_SPI_DMA_BUF_LEN			(16*1024)
+#define TX_FIFO_EMPTY_COUNT_MAX			SPI_TX_FIFO_EMPTY_COUNT(0x40)
+#define RX_FIFO_FULL_COUNT_ZERO			SPI_RX_FIFO_FULL_COUNT(0)
+#define MAX_HOLD_CYCLES				16
+#define SPI_DEFAULT_SPEED			25000000
+
+#define MAX_CHIP_SELECT				4
+#define SPI_FIFO_DEPTH				64
+
+struct tegra_spi_data {
+	struct device				*dev;
+	struct spi_master			*master;
+	spinlock_t				lock;
+
+	struct clk				*clk;
+	void __iomem				*base;
+	phys_addr_t				phys;
+	unsigned				irq;
+	int					dma_req_sel;
+	u32					spi_max_frequency;
+	u32					cur_speed;
+
+	struct spi_device			*cur_spi;
+	unsigned				cur_pos;
+	unsigned				cur_len;
+	unsigned				words_per_32bit;
+	unsigned				bytes_per_word;
+	unsigned				curr_dma_words;
+	unsigned				cur_direction;
+
+	unsigned				cur_rx_pos;
+	unsigned				cur_tx_pos;
+
+	unsigned				dma_buf_size;
+	unsigned				max_buf_size;
+	bool					is_curr_dma_xfer;
+
+	struct completion			rx_dma_complete;
+	struct completion			tx_dma_complete;
+
+	u32					tx_status;
+	u32					rx_status;
+	u32					status_reg;
+	bool					is_packed;
+	unsigned long				packed_size;
+
+	u32					command1_reg;
+	u32					dma_control_reg;
+	u32					def_command1_reg;
+	u32					spi_cs_timing;
+
+	struct completion			xfer_completion;
+	struct spi_transfer			*curr_xfer;
+	struct dma_chan				*rx_dma_chan;
+	u32					*rx_dma_buf;
+	dma_addr_t				rx_dma_phys;
+	struct dma_async_tx_descriptor		*rx_dma_desc;
+
+	struct dma_chan				*tx_dma_chan;
+	u32					*tx_dma_buf;
+	dma_addr_t				tx_dma_phys;
+	struct dma_async_tx_descriptor		*tx_dma_desc;
+};
+
+static int tegra_spi_runtime_suspend(struct device *dev);
+static int tegra_spi_runtime_resume(struct device *dev);
+
+static inline unsigned long tegra_spi_readl(struct tegra_spi_data *tspi,
+		unsigned long reg)
+{
+	return readl(tspi->base + reg);
+}
+
+static inline void tegra_spi_writel(struct tegra_spi_data *tspi,
+		unsigned long val, unsigned long reg)
+{
+	writel(val, tspi->base + reg);
+
+	/* Read back register to make sure that register writes completed */
+	if (reg != SPI_TX_FIFO)
+		readl(tspi->base + SPI_COMMAND1);
+}
+
+static void tegra_spi_clear_status(struct tegra_spi_data *tspi)
+{
+	unsigned long val;
+
+	/* Write 1 to clear status register */
+	val = tegra_spi_readl(tspi, SPI_TRANS_STATUS);
+	tegra_spi_writel(tspi, val, SPI_TRANS_STATUS);
+
+	/* Clear fifo status error if any */
+	val = tegra_spi_readl(tspi, SPI_FIFO_STATUS);
+	if (val & SPI_ERR)
+		tegra_spi_writel(tspi, SPI_ERR | SPI_FIFO_ERROR,
+				SPI_FIFO_STATUS);
+}
+
+static unsigned tegra_spi_calculate_curr_xfer_param(
+	struct spi_device *spi, struct tegra_spi_data *tspi,
+	struct spi_transfer *t)
+{
+	unsigned remain_len = t->len - tspi->cur_pos;
+	unsigned max_word;
+	unsigned bits_per_word = t->bits_per_word;
+	unsigned max_len;
+	unsigned total_fifo_words;
+
+	tspi->bytes_per_word = (bits_per_word - 1) / 8 + 1;
+
+	if (bits_per_word == 8 || bits_per_word == 16) {
+		tspi->is_packed = 1;
+		tspi->words_per_32bit = 32/bits_per_word;
+	} else {
+		tspi->is_packed = 0;
+		tspi->words_per_32bit = 1;
+	}
+
+	if (tspi->is_packed) {
+		max_len = min(remain_len, tspi->max_buf_size);
+		tspi->curr_dma_words = max_len/tspi->bytes_per_word;
+		total_fifo_words = (max_len + 3) / 4;
+	} else {
+		max_word = (remain_len - 1) / tspi->bytes_per_word + 1;
+		max_word = min(max_word, tspi->max_buf_size/4);
+		tspi->curr_dma_words = max_word;
+		total_fifo_words = max_word;
+	}
+	return total_fifo_words;
+}
+
+static unsigned tegra_spi_fill_tx_fifo_from_client_txbuf(
+	struct tegra_spi_data *tspi, struct spi_transfer *t)
+{
+	unsigned nbytes;
+	unsigned tx_empty_count;
+	unsigned long fifo_status;
+	unsigned max_n_32bit;
+	unsigned i, count;
+	unsigned long x;
+	unsigned int written_words;
+	unsigned fifo_words_left;
+	u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_tx_pos;
+
+	fifo_status = tegra_spi_readl(tspi, SPI_FIFO_STATUS);
+	tx_empty_count = SPI_TX_FIFO_EMPTY_COUNT(fifo_status);
+
+	if (tspi->is_packed) {
+		fifo_words_left = tx_empty_count * tspi->words_per_32bit;
+		written_words = min(fifo_words_left, tspi->curr_dma_words);
+		nbytes = written_words * tspi->bytes_per_word;
+		max_n_32bit = DIV_ROUND_UP(nbytes, 4);
+		for (count = 0; count < max_n_32bit; count++) {
+			x = 0;
+			for (i = 0; (i < 4) && nbytes; i++, nbytes--)
+				x |= (*tx_buf++) << (i*8);
+			tegra_spi_writel(tspi, x, SPI_TX_FIFO);
+		}
+	} else {
+		max_n_32bit = min(tspi->curr_dma_words,  tx_empty_count);
+		written_words = max_n_32bit;
+		nbytes = written_words * tspi->bytes_per_word;
+		for (count = 0; count < max_n_32bit; count++) {
+			x = 0;
+			for (i = 0; nbytes && (i < tspi->bytes_per_word);
+							i++, nbytes--)
+				x |= ((*tx_buf++) << i*8);
+			tegra_spi_writel(tspi, x, SPI_TX_FIFO);
+		}
+	}
+	tspi->cur_tx_pos += written_words * tspi->bytes_per_word;
+	return written_words;
+}
+
+static unsigned int tegra_spi_read_rx_fifo_to_client_rxbuf(
+		struct tegra_spi_data *tspi, struct spi_transfer *t)
+{
+	unsigned rx_full_count;
+	unsigned long fifo_status;
+	unsigned i, count;
+	unsigned long x;
+	unsigned int read_words = 0;
+	unsigned len;
+	u8 *rx_buf = (u8 *)t->rx_buf + tspi->cur_rx_pos;
+
+	fifo_status = tegra_spi_readl(tspi, SPI_FIFO_STATUS);
+	rx_full_count = SPI_RX_FIFO_FULL_COUNT(fifo_status);
+	if (tspi->is_packed) {
+		len = tspi->curr_dma_words * tspi->bytes_per_word;
+		for (count = 0; count < rx_full_count; count++) {
+			x = tegra_spi_readl(tspi, SPI_RX_FIFO);
+			for (i = 0; len && (i < 4); i++, len--)
+				*rx_buf++ = (x >> i*8) & 0xFF;
+		}
+		tspi->cur_rx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
+		read_words += tspi->curr_dma_words;
+	} else {
+		unsigned int rx_mask;
+		unsigned int bits_per_word = t->bits_per_word;
+
+		rx_mask = (1 << bits_per_word) - 1;
+		for (count = 0; count < rx_full_count; count++) {
+			x = tegra_spi_readl(tspi, SPI_RX_FIFO);
+			x &= rx_mask;
+			for (i = 0; (i < tspi->bytes_per_word); i++)
+				*rx_buf++ = (x >> (i*8)) & 0xFF;
+		}
+		tspi->cur_rx_pos += rx_full_count * tspi->bytes_per_word;
+		read_words += rx_full_count;
+	}
+	return read_words;
+}
+
+static void tegra_spi_copy_client_txbuf_to_spi_txbuf(
+		struct tegra_spi_data *tspi, struct spi_transfer *t)
+{
+	unsigned len;
+
+	/* Make the dma buffer to read by cpu */
+	dma_sync_single_for_cpu(tspi->dev, tspi->tx_dma_phys,
+				tspi->dma_buf_size, DMA_TO_DEVICE);
+
+	if (tspi->is_packed) {
+		len = tspi->curr_dma_words * tspi->bytes_per_word;
+		memcpy(tspi->tx_dma_buf, t->tx_buf + tspi->cur_pos, len);
+	} else {
+		unsigned int i;
+		unsigned int count;
+		u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_tx_pos;
+		unsigned consume = tspi->curr_dma_words * tspi->bytes_per_word;
+		unsigned int x;
+
+		for (count = 0; count < tspi->curr_dma_words; count++) {
+			x = 0;
+			for (i = 0; consume && (i < tspi->bytes_per_word);
+							i++, consume--)
+				x |= ((*tx_buf++) << i * 8);
+			tspi->tx_dma_buf[count] = x;
+		}
+	}
+	tspi->cur_tx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
+
+	/* Make the dma buffer to read by dma */
+	dma_sync_single_for_device(tspi->dev, tspi->tx_dma_phys,
+				tspi->dma_buf_size, DMA_TO_DEVICE);
+}
+
+static void tegra_spi_copy_spi_rxbuf_to_client_rxbuf(
+		struct tegra_spi_data *tspi, struct spi_transfer *t)
+{
+	unsigned len;
+
+	/* Make the dma buffer to read by cpu */
+	dma_sync_single_for_cpu(tspi->dev, tspi->rx_dma_phys,
+		tspi->dma_buf_size, DMA_FROM_DEVICE);
+
+	if (tspi->is_packed) {
+		len = tspi->curr_dma_words * tspi->bytes_per_word;
+		memcpy(t->rx_buf + tspi->cur_rx_pos, tspi->rx_dma_buf, len);
+	} else {
+		unsigned int i;
+		unsigned int count;
+		unsigned char *rx_buf = t->rx_buf + tspi->cur_rx_pos;
+		unsigned int x;
+		unsigned int rx_mask;
+		unsigned int bits_per_word = t->bits_per_word;
+
+		rx_mask = (1 << bits_per_word) - 1;
+		for (count = 0; count < tspi->curr_dma_words; count++) {
+			x = tspi->rx_dma_buf[count];
+			x &= rx_mask;
+			for (i = 0; (i < tspi->bytes_per_word); i++)
+				*rx_buf++ = (x >> (i*8)) & 0xFF;
+		}
+	}
+	tspi->cur_rx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
+
+	/* Make the dma buffer to read by dma */
+	dma_sync_single_for_device(tspi->dev, tspi->rx_dma_phys,
+		tspi->dma_buf_size, DMA_FROM_DEVICE);
+}
+
+static void tegra_spi_dma_complete(void *args)
+{
+	struct completion *dma_complete = args;
+
+	complete(dma_complete);
+}
+
+static int tegra_spi_start_tx_dma(struct tegra_spi_data *tspi, int len)
+{
+	INIT_COMPLETION(tspi->tx_dma_complete);
+	tspi->tx_dma_desc = dmaengine_prep_slave_single(tspi->tx_dma_chan,
+				tspi->tx_dma_phys, len, DMA_MEM_TO_DEV,
+				DMA_PREP_INTERRUPT |  DMA_CTRL_ACK);
+	if (!tspi->tx_dma_desc) {
+		dev_err(tspi->dev, "Not able to get desc for Tx\n");
+		return -EIO;
+	}
+
+	tspi->tx_dma_desc->callback = tegra_spi_dma_complete;
+	tspi->tx_dma_desc->callback_param = &tspi->tx_dma_complete;
+
+	dmaengine_submit(tspi->tx_dma_desc);
+	dma_async_issue_pending(tspi->tx_dma_chan);
+	return 0;
+}
+
+static int tegra_spi_start_rx_dma(struct tegra_spi_data *tspi, int len)
+{
+	INIT_COMPLETION(tspi->rx_dma_complete);
+	tspi->rx_dma_desc = dmaengine_prep_slave_single(tspi->rx_dma_chan,
+				tspi->rx_dma_phys, len, DMA_DEV_TO_MEM,
+				DMA_PREP_INTERRUPT |  DMA_CTRL_ACK);
+	if (!tspi->rx_dma_desc) {
+		dev_err(tspi->dev, "Not able to get desc for Rx\n");
+		return -EIO;
+	}
+
+	tspi->rx_dma_desc->callback = tegra_spi_dma_complete;
+	tspi->rx_dma_desc->callback_param = &tspi->rx_dma_complete;
+
+	dmaengine_submit(tspi->rx_dma_desc);
+	dma_async_issue_pending(tspi->rx_dma_chan);
+	return 0;
+}
+
+static int tegra_spi_start_dma_based_transfer(
+		struct tegra_spi_data *tspi, struct spi_transfer *t)
+{
+	unsigned long val;
+	unsigned int len;
+	int ret = 0;
+	unsigned long status;
+
+	/* Make sure that Rx and Tx fifo are empty */
+	status = tegra_spi_readl(tspi, SPI_FIFO_STATUS);
+	if ((status & SPI_FIFO_EMPTY) != SPI_FIFO_EMPTY) {
+		dev_err(tspi->dev,
+			"Rx/Tx fifo are not empty status 0x%08lx\n", status);
+		return -EIO;
+	}
+
+	val = SPI_DMA_BLK_SET(tspi->curr_dma_words - 1);
+	tegra_spi_writel(tspi, val, SPI_DMA_BLK);
+
+	if (tspi->is_packed)
+		len = DIV_ROUND_UP(tspi->curr_dma_words * tspi->bytes_per_word,
+					4) * 4;
+	else
+		len = tspi->curr_dma_words * 4;
+
+	/* Set attention level based on length of transfer */
+	if (len & 0xF)
+		val |= SPI_TX_TRIG_1 | SPI_RX_TRIG_1;
+	else if (((len) >> 4) & 0x1)
+		val |= SPI_TX_TRIG_4 | SPI_RX_TRIG_4;
+	else
+		val |= SPI_TX_TRIG_8 | SPI_RX_TRIG_8;
+
+	if (tspi->cur_direction & DATA_DIR_TX)
+		val |= SPI_IE_TX;
+
+	if (tspi->cur_direction & DATA_DIR_RX)
+		val |= SPI_IE_RX;
+
+	tegra_spi_writel(tspi, val, SPI_DMA_CTL);
+	tspi->dma_control_reg = val;
+
+	if (tspi->cur_direction & DATA_DIR_TX) {
+		tegra_spi_copy_client_txbuf_to_spi_txbuf(tspi, t);
+		ret = tegra_spi_start_tx_dma(tspi, len);
+		if (ret < 0) {
+			dev_err(tspi->dev,
+				"Starting tx dma failed, err %d\n", ret);
+			return ret;
+		}
+	}
+
+	if (tspi->cur_direction & DATA_DIR_RX) {
+		/* Make the dma buffer to read by dma */
+		dma_sync_single_for_device(tspi->dev, tspi->rx_dma_phys,
+				tspi->dma_buf_size, DMA_FROM_DEVICE);
+
+		ret = tegra_spi_start_rx_dma(tspi, len);
+		if (ret < 0) {
+			dev_err(tspi->dev,
+				"Starting rx dma failed, err %d\n", ret);
+			if (tspi->cur_direction & DATA_DIR_TX)
+				dmaengine_terminate_all(tspi->tx_dma_chan);
+			return ret;
+		}
+	}
+	tspi->is_curr_dma_xfer = true;
+	tspi->dma_control_reg = val;
+
+	val |= SPI_DMA_EN;
+	tegra_spi_writel(tspi, val, SPI_DMA_CTL);
+	return ret;
+}
+
+static int tegra_spi_start_cpu_based_transfer(
+		struct tegra_spi_data *tspi, struct spi_transfer *t)
+{
+	unsigned long val;
+	unsigned cur_words;
+
+	if (tspi->cur_direction & DATA_DIR_TX)
+		cur_words = tegra_spi_fill_tx_fifo_from_client_txbuf(tspi, t);
+	else
+		cur_words = tspi->curr_dma_words;
+
+	val = SPI_DMA_BLK_SET(cur_words - 1);
+	tegra_spi_writel(tspi, val, SPI_DMA_BLK);
+
+	val = 0;
+	if (tspi->cur_direction & DATA_DIR_TX)
+		val |= SPI_IE_TX;
+
+	if (tspi->cur_direction & DATA_DIR_RX)
+		val |= SPI_IE_RX;
+
+	tegra_spi_writel(tspi, val, SPI_DMA_CTL);
+	tspi->dma_control_reg = val;
+
+	tspi->is_curr_dma_xfer = false;
+
+	val |= SPI_DMA_EN;
+	tegra_spi_writel(tspi, val, SPI_DMA_CTL);
+	return 0;
+}
+
+static int tegra_spi_init_dma_param(struct tegra_spi_data *tspi,
+			bool dma_to_memory)
+{
+	struct dma_chan *dma_chan;
+	u32 *dma_buf;
+	dma_addr_t dma_phys;
+	int ret;
+	struct dma_slave_config dma_sconfig;
+	dma_cap_mask_t mask;
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+	dma_chan = dma_request_channel(mask, NULL, NULL);
+	if (!dma_chan) {
+		dev_err(tspi->dev,
+			"Dma channel is not available, will try later\n");
+		return -EPROBE_DEFER;
+	}
+
+	dma_buf = dma_alloc_coherent(tspi->dev, tspi->dma_buf_size,
+				&dma_phys, GFP_KERNEL);
+	if (!dma_buf) {
+		dev_err(tspi->dev, " Not able to allocate the dma buffer\n");
+		dma_release_channel(dma_chan);
+		return -ENOMEM;
+	}
+
+	dma_sconfig.slave_id = tspi->dma_req_sel;
+	if (dma_to_memory) {
+		dma_sconfig.src_addr = tspi->phys + SPI_RX_FIFO;
+		dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+		dma_sconfig.src_maxburst = 0;
+	} else {
+		dma_sconfig.dst_addr = tspi->phys + SPI_TX_FIFO;
+		dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+		dma_sconfig.dst_maxburst = 0;
+	}
+
+	ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
+	if (ret)
+		goto scrub;
+	if (dma_to_memory) {
+		tspi->rx_dma_chan = dma_chan;
+		tspi->rx_dma_buf = dma_buf;
+		tspi->rx_dma_phys = dma_phys;
+	} else {
+		tspi->tx_dma_chan = dma_chan;
+		tspi->tx_dma_buf = dma_buf;
+		tspi->tx_dma_phys = dma_phys;
+	}
+	return 0;
+
+scrub:
+	dma_free_coherent(tspi->dev, tspi->dma_buf_size, dma_buf, dma_phys);
+	dma_release_channel(dma_chan);
+	return ret;
+}
+
+static void tegra_spi_deinit_dma_param(struct tegra_spi_data *tspi,
+	bool dma_to_memory)
+{
+	u32 *dma_buf;
+	dma_addr_t dma_phys;
+	struct dma_chan *dma_chan;
+
+	if (dma_to_memory) {
+		dma_buf = tspi->rx_dma_buf;
+		dma_chan = tspi->rx_dma_chan;
+		dma_phys = tspi->rx_dma_phys;
+		tspi->rx_dma_chan = NULL;
+		tspi->rx_dma_buf = NULL;
+	} else {
+		dma_buf = tspi->tx_dma_buf;
+		dma_chan = tspi->tx_dma_chan;
+		dma_phys = tspi->tx_dma_phys;
+		tspi->tx_dma_buf = NULL;
+		tspi->tx_dma_chan = NULL;
+	}
+	if (!dma_chan)
+		return;
+
+	dma_free_coherent(tspi->dev, tspi->dma_buf_size, dma_buf, dma_phys);
+	dma_release_channel(dma_chan);
+}
+
+static int tegra_spi_start_transfer_one(struct spi_device *spi,
+		struct spi_transfer *t, bool is_first_of_msg,
+		bool is_single_xfer)
+{
+	struct tegra_spi_data *tspi = spi_master_get_devdata(spi->master);
+	u32 speed = t->speed_hz;
+	u8 bits_per_word = t->bits_per_word;
+	unsigned total_fifo_words;
+	int ret;
+	unsigned long command1;
+	int req_mode;
+
+	if (speed != tspi->cur_speed) {
+		clk_set_rate(tspi->clk, speed);
+		tspi->cur_speed = speed;
+	}
+
+	tspi->cur_spi = spi;
+	tspi->cur_pos = 0;
+	tspi->cur_rx_pos = 0;
+	tspi->cur_tx_pos = 0;
+	tspi->curr_xfer = t;
+	total_fifo_words = tegra_spi_calculate_curr_xfer_param(spi, tspi, t);
+
+	if (is_first_of_msg) {
+		tegra_spi_clear_status(tspi);
+
+		command1 = tspi->def_command1_reg;
+		command1 |= SPI_BIT_LENGTH(bits_per_word - 1);
+
+		command1 &= ~SPI_CONTROL_MODE_MASK;
+		req_mode = spi->mode & 0x3;
+		if (req_mode == SPI_MODE_0)
+			command1 |= SPI_CONTROL_MODE_0;
+		else if (req_mode == SPI_MODE_1)
+			command1 |= SPI_CONTROL_MODE_1;
+		else if (req_mode == SPI_MODE_2)
+			command1 |= SPI_CONTROL_MODE_2;
+		else if (req_mode == SPI_MODE_3)
+			command1 |= SPI_CONTROL_MODE_3;
+
+		tegra_spi_writel(tspi, command1, SPI_COMMAND1);
+
+		command1 |= SPI_CS_SW_HW;
+		if (spi->mode & SPI_CS_HIGH)
+			command1 |= SPI_CS_SS_VAL;
+		else
+			command1 &= ~SPI_CS_SS_VAL;
+
+		tegra_spi_writel(tspi, 0, SPI_COMMAND2);
+	} else {
+		command1 = tspi->command1_reg;
+		command1 &= ~SPI_BIT_LENGTH(~0);
+		command1 |= SPI_BIT_LENGTH(bits_per_word - 1);
+	}
+
+	if (tspi->is_packed)
+		command1 |= SPI_PACKED;
+
+	command1 &= ~(SPI_CS_SEL_MASK | SPI_TX_EN | SPI_RX_EN);
+	tspi->cur_direction = 0;
+	if (t->rx_buf) {
+		command1 |= SPI_RX_EN;
+		tspi->cur_direction |= DATA_DIR_RX;
+	}
+	if (t->tx_buf) {
+		command1 |= SPI_TX_EN;
+		tspi->cur_direction |= DATA_DIR_TX;
+	}
+	command1 |= SPI_CS_SEL(spi->chip_select);
+	tegra_spi_writel(tspi, command1, SPI_COMMAND1);
+	tspi->command1_reg = command1;
+
+	dev_dbg(tspi->dev, "The def 0x%x and written 0x%lx\n",
+				tspi->def_command1_reg, command1);
+
+	if (total_fifo_words > SPI_FIFO_DEPTH)
+		ret = tegra_spi_start_dma_based_transfer(tspi, t);
+	else
+		ret = tegra_spi_start_cpu_based_transfer(tspi, t);
+	return ret;
+}
+
+static int tegra_spi_setup(struct spi_device *spi)
+{
+	struct tegra_spi_data *tspi = spi_master_get_devdata(spi->master);
+	unsigned long val;
+	unsigned long flags;
+	int ret;
+	unsigned int cs_pol_bit[MAX_CHIP_SELECT] = {
+			SPI_CS_POL_INACTIVE_0,
+			SPI_CS_POL_INACTIVE_1,
+			SPI_CS_POL_INACTIVE_2,
+			SPI_CS_POL_INACTIVE_3,
+	};
+
+	dev_dbg(&spi->dev, "setup %d bpw, %scpol, %scpha, %dHz\n",
+		spi->bits_per_word,
+		spi->mode & SPI_CPOL ? "" : "~",
+		spi->mode & SPI_CPHA ? "" : "~",
+		spi->max_speed_hz);
+
+	BUG_ON(spi->chip_select >= MAX_CHIP_SELECT);
+
+	/* Set speed to the spi max fequency if spi device has not set */
+	spi->max_speed_hz = spi->max_speed_hz ? : tspi->spi_max_frequency;
+
+	ret = pm_runtime_get_sync(tspi->dev);
+	if (ret < 0) {
+		dev_err(tspi->dev, "pm runtime failed, e = %d\n", ret);
+		return ret;
+	}
+
+	spin_lock_irqsave(&tspi->lock, flags);
+	val = tspi->def_command1_reg;
+	if (spi->mode & SPI_CS_HIGH)
+		val &= ~cs_pol_bit[spi->chip_select];
+	else
+		val |= cs_pol_bit[spi->chip_select];
+	tspi->def_command1_reg = val;
+	tegra_spi_writel(tspi, tspi->def_command1_reg, SPI_COMMAND1);
+	spin_unlock_irqrestore(&tspi->lock, flags);
+
+	pm_runtime_put(tspi->dev);
+	return 0;
+}
+
+static int tegra_spi_transfer_one_message(struct spi_master *master,
+			struct spi_message *msg)
+{
+	bool is_first_msg = true;
+	int single_xfer;
+	struct tegra_spi_data *tspi = spi_master_get_devdata(master);
+	struct spi_transfer *xfer;
+	struct spi_device *spi = msg->spi;
+	int ret;
+
+	msg->status = 0;
+	msg->actual_length = 0;
+
+	ret = pm_runtime_get_sync(tspi->dev);
+	if (ret < 0) {
+		dev_err(tspi->dev, "runtime PM get failed: %d\n", ret);
+		msg->status = ret;
+		spi_finalize_current_message(master);
+		return ret;
+	}
+
+	single_xfer = list_is_singular(&msg->transfers);
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		INIT_COMPLETION(tspi->xfer_completion);
+		ret = tegra_spi_start_transfer_one(spi, xfer,
+					is_first_msg, single_xfer);
+		if (ret < 0) {
+			dev_err(tspi->dev,
+				"spi can not start transfer, err %d\n", ret);
+			goto exit;
+		}
+		is_first_msg = false;
+		ret = wait_for_completion_timeout(&tspi->xfer_completion,
+						SPI_DMA_TIMEOUT);
+		if (WARN_ON(ret == 0)) {
+			dev_err(tspi->dev,
+				"spi trasfer timeout, err %d\n", ret);
+			ret = -EIO;
+			goto exit;
+		}
+
+		if (tspi->tx_status ||  tspi->rx_status) {
+			dev_err(tspi->dev, "Error in Transfer\n");
+			ret = -EIO;
+			goto exit;
+		}
+		msg->actual_length += xfer->len;
+		if (xfer->cs_change && xfer->delay_usecs) {
+			tegra_spi_writel(tspi, tspi->def_command1_reg,
+					SPI_COMMAND1);
+			udelay(xfer->delay_usecs);
+		}
+	}
+	ret = 0;
+exit:
+	tegra_spi_writel(tspi, tspi->def_command1_reg, SPI_COMMAND1);
+	pm_runtime_put(tspi->dev);
+	msg->status = ret;
+	spi_finalize_current_message(master);
+	return ret;
+}
+
+static irqreturn_t handle_cpu_based_xfer(struct tegra_spi_data *tspi)
+{
+	struct spi_transfer *t = tspi->curr_xfer;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tspi->lock, flags);
+	if (tspi->tx_status ||  tspi->rx_status) {
+		dev_err(tspi->dev, "CpuXfer ERROR bit set 0x%x\n",
+			tspi->status_reg);
+		dev_err(tspi->dev, "CpuXfer 0x%08x:0x%08x\n",
+			tspi->command1_reg, tspi->dma_control_reg);
+		tegra_periph_reset_assert(tspi->clk);
+		udelay(2);
+		tegra_periph_reset_deassert(tspi->clk);
+		complete(&tspi->xfer_completion);
+		goto exit;
+	}
+
+	if (tspi->cur_direction & DATA_DIR_RX)
+		tegra_spi_read_rx_fifo_to_client_rxbuf(tspi, t);
+
+	if (tspi->cur_direction & DATA_DIR_TX)
+		tspi->cur_pos = tspi->cur_tx_pos;
+	else
+		tspi->cur_pos = tspi->cur_rx_pos;
+
+	if (tspi->cur_pos == t->len) {
+		complete(&tspi->xfer_completion);
+		goto exit;
+	}
+
+	tegra_spi_calculate_curr_xfer_param(tspi->cur_spi, tspi, t);
+	tegra_spi_start_cpu_based_transfer(tspi, t);
+exit:
+	spin_unlock_irqrestore(&tspi->lock, flags);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t handle_dma_based_xfer(struct tegra_spi_data *tspi)
+{
+	struct spi_transfer *t = tspi->curr_xfer;
+	long wait_status;
+	int err = 0;
+	unsigned total_fifo_words;
+	unsigned long flags;
+
+	/* Abort dmas if any error */
+	if (tspi->cur_direction & DATA_DIR_TX) {
+		if (tspi->tx_status) {
+			dmaengine_terminate_all(tspi->tx_dma_chan);
+			err += 1;
+		} else {
+			wait_status = wait_for_completion_interruptible_timeout(
+				&tspi->tx_dma_complete, SPI_DMA_TIMEOUT);
+			if (wait_status <= 0) {
+				dmaengine_terminate_all(tspi->tx_dma_chan);
+				dev_err(tspi->dev, "TxDma Xfer failed\n");
+				err += 1;
+			}
+		}
+	}
+
+	if (tspi->cur_direction & DATA_DIR_RX) {
+		if (tspi->rx_status) {
+			dmaengine_terminate_all(tspi->rx_dma_chan);
+			err += 2;
+		} else {
+			wait_status = wait_for_completion_interruptible_timeout(
+				&tspi->rx_dma_complete, SPI_DMA_TIMEOUT);
+			if (wait_status <= 0) {
+				dmaengine_terminate_all(tspi->rx_dma_chan);
+				dev_err(tspi->dev, "RxDma Xfer failed\n");
+				err += 2;
+			}
+		}
+	}
+
+	spin_lock_irqsave(&tspi->lock, flags);
+	if (err) {
+		dev_err(tspi->dev, "DmaXfer: ERROR bit set 0x%x\n",
+			tspi->status_reg);
+		dev_err(tspi->dev, "DmaXfer 0x%08x:0x%08x\n",
+			tspi->command1_reg, tspi->dma_control_reg);
+		tegra_periph_reset_assert(tspi->clk);
+		udelay(2);
+		tegra_periph_reset_deassert(tspi->clk);
+		complete(&tspi->xfer_completion);
+		spin_unlock_irqrestore(&tspi->lock, flags);
+		return IRQ_HANDLED;
+	}
+
+	if (tspi->cur_direction & DATA_DIR_RX)
+		tegra_spi_copy_spi_rxbuf_to_client_rxbuf(tspi, t);
+
+	if (tspi->cur_direction & DATA_DIR_TX)
+		tspi->cur_pos = tspi->cur_tx_pos;
+	else
+		tspi->cur_pos = tspi->cur_rx_pos;
+
+	if (tspi->cur_pos == t->len) {
+		complete(&tspi->xfer_completion);
+		goto exit;
+	}
+
+	/* Continue transfer in current message */
+	total_fifo_words = tegra_spi_calculate_curr_xfer_param(tspi->cur_spi,
+							tspi, t);
+	if (total_fifo_words > SPI_FIFO_DEPTH)
+		err = tegra_spi_start_dma_based_transfer(tspi, t);
+	else
+		err = tegra_spi_start_cpu_based_transfer(tspi, t);
+
+exit:
+	spin_unlock_irqrestore(&tspi->lock, flags);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t tegra_spi_isr_thread(int irq, void *context_data)
+{
+	struct tegra_spi_data *tspi = context_data;
+
+	if (!tspi->is_curr_dma_xfer)
+		return handle_cpu_based_xfer(tspi);
+	return handle_dma_based_xfer(tspi);
+}
+
+static irqreturn_t tegra_spi_isr(int irq, void *context_data)
+{
+	struct tegra_spi_data *tspi = context_data;
+
+	tspi->status_reg = tegra_spi_readl(tspi, SPI_FIFO_STATUS);
+	if (tspi->cur_direction & DATA_DIR_TX)
+		tspi->tx_status = tspi->status_reg &
+					(SPI_TX_FIFO_UNF | SPI_TX_FIFO_OVF);
+
+	if (tspi->cur_direction & DATA_DIR_RX)
+		tspi->rx_status = tspi->status_reg &
+					(SPI_RX_FIFO_OVF | SPI_RX_FIFO_UNF);
+	tegra_spi_clear_status(tspi);
+
+	return IRQ_WAKE_THREAD;
+}
+
+static void tegra_spi_parse_dt(struct platform_device *pdev,
+	struct tegra_spi_data *tspi)
+{
+	struct device_node *np = pdev->dev.of_node;
+	u32 of_dma[2];
+
+	if (of_property_read_u32_array(np, "nvidia,dma-request-selector",
+				of_dma, 2) >= 0)
+		tspi->dma_req_sel = of_dma[1];
+
+	if (of_property_read_u32(np, "spi-max-frequency",
+				&tspi->spi_max_frequency))
+		tspi->spi_max_frequency = 25000000; /* 25MHz */
+}
+
+static struct of_device_id tegra_spi_of_match[] = {
+	{ .compatible = "nvidia,tegra114-spi", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, tegra_spi_of_match);
+
+static int tegra_spi_probe(struct platform_device *pdev)
+{
+	struct spi_master	*master;
+	struct tegra_spi_data	*tspi;
+	struct resource		*r;
+	int ret, spi_irq;
+
+	master = spi_alloc_master(&pdev->dev, sizeof(*tspi));
+	if (!master) {
+		dev_err(&pdev->dev, "master allocation failed\n");
+		return -ENOMEM;
+	}
+	dev_set_drvdata(&pdev->dev, master);
+	tspi = spi_master_get_devdata(master);
+
+	/* Parse DT */
+	tegra_spi_parse_dt(pdev, tspi);
+
+	/* the spi->mode bits understood by this driver: */
+	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+	master->setup = tegra_spi_setup;
+	master->transfer_one_message = tegra_spi_transfer_one_message;
+	master->num_chipselect = MAX_CHIP_SELECT;
+	master->bus_num = -1;
+
+	tspi->master = master;
+	tspi->dev = &pdev->dev;
+	spin_lock_init(&tspi->lock);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!r) {
+		dev_err(&pdev->dev, "No IO memory resource\n");
+		ret = -ENODEV;
+		goto exit_free_master;
+	}
+	tspi->phys = r->start;
+	tspi->base = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(tspi->base)) {
+		ret = PTR_ERR(tspi->base);
+		dev_err(&pdev->dev, "ioremap failed: err = %d\n", ret);
+		goto exit_free_master;
+	}
+
+	spi_irq = platform_get_irq(pdev, 0);
+	tspi->irq = spi_irq;
+	ret = request_threaded_irq(tspi->irq, tegra_spi_isr,
+			tegra_spi_isr_thread, IRQF_ONESHOT,
+			dev_name(&pdev->dev), tspi);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n",
+					tspi->irq);
+		goto exit_free_master;
+	}
+
+	tspi->clk = devm_clk_get(&pdev->dev, "spi");
+	if (IS_ERR(tspi->clk)) {
+		dev_err(&pdev->dev, "can not get clock\n");
+		ret = PTR_ERR(tspi->clk);
+		goto exit_free_irq;
+	}
+
+	tspi->max_buf_size = SPI_FIFO_DEPTH << 2;
+	tspi->dma_buf_size = DEFAULT_SPI_DMA_BUF_LEN;
+
+	if (tspi->dma_req_sel) {
+		ret = tegra_spi_init_dma_param(tspi, true);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "RxDma Init failed, err %d\n", ret);
+			goto exit_free_irq;
+		}
+
+		ret = tegra_spi_init_dma_param(tspi, false);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "TxDma Init failed, err %d\n", ret);
+			goto exit_rx_dma_free;
+		}
+		tspi->max_buf_size = tspi->dma_buf_size;
+		init_completion(&tspi->tx_dma_complete);
+		init_completion(&tspi->rx_dma_complete);
+	}
+
+	init_completion(&tspi->xfer_completion);
+
+	pm_runtime_enable(&pdev->dev);
+	if (!pm_runtime_enabled(&pdev->dev)) {
+		ret = tegra_spi_runtime_resume(&pdev->dev);
+		if (ret)
+			goto exit_pm_disable;
+	}
+
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret);
+		goto exit_pm_disable;
+	}
+	tspi->def_command1_reg  = SPI_M_S;
+	tegra_spi_writel(tspi, tspi->def_command1_reg, SPI_COMMAND1);
+	pm_runtime_put(&pdev->dev);
+
+	master->dev.of_node = pdev->dev.of_node;
+	ret = spi_register_master(master);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "can not register to master err %d\n", ret);
+		goto exit_pm_disable;
+	}
+	return ret;
+
+exit_pm_disable:
+	pm_runtime_disable(&pdev->dev);
+	if (!pm_runtime_status_suspended(&pdev->dev))
+		tegra_spi_runtime_suspend(&pdev->dev);
+	tegra_spi_deinit_dma_param(tspi, false);
+exit_rx_dma_free:
+	tegra_spi_deinit_dma_param(tspi, true);
+exit_free_irq:
+	free_irq(spi_irq, tspi);
+exit_free_master:
+	spi_master_put(master);
+	return ret;
+}
+
+static int tegra_spi_remove(struct platform_device *pdev)
+{
+	struct spi_master *master = dev_get_drvdata(&pdev->dev);
+	struct tegra_spi_data	*tspi = spi_master_get_devdata(master);
+
+	free_irq(tspi->irq, tspi);
+	spi_unregister_master(master);
+
+	if (tspi->tx_dma_chan)
+		tegra_spi_deinit_dma_param(tspi, false);
+
+	if (tspi->rx_dma_chan)
+		tegra_spi_deinit_dma_param(tspi, true);
+
+	pm_runtime_disable(&pdev->dev);
+	if (!pm_runtime_status_suspended(&pdev->dev))
+		tegra_spi_runtime_suspend(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tegra_spi_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+
+	return spi_master_suspend(master);
+}
+
+static int tegra_spi_resume(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct tegra_spi_data *tspi = spi_master_get_devdata(master);
+	int ret;
+
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		dev_err(dev, "pm runtime failed, e = %d\n", ret);
+		return ret;
+	}
+	tegra_spi_writel(tspi, tspi->command1_reg, SPI_COMMAND1);
+	pm_runtime_put(dev);
+
+	return spi_master_resume(master);
+}
+#endif
+
+static int tegra_spi_runtime_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct tegra_spi_data *tspi = spi_master_get_devdata(master);
+
+	/* Flush all write which are in PPSB queue by reading back */
+	tegra_spi_readl(tspi, SPI_COMMAND1);
+
+	clk_disable_unprepare(tspi->clk);
+	return 0;
+}
+
+static int tegra_spi_runtime_resume(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct tegra_spi_data *tspi = spi_master_get_devdata(master);
+	int ret;
+
+	ret = clk_prepare_enable(tspi->clk);
+	if (ret < 0) {
+		dev_err(tspi->dev, "clk_prepare failed: %d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+static const struct dev_pm_ops tegra_spi_pm_ops = {
+	SET_RUNTIME_PM_OPS(tegra_spi_runtime_suspend,
+		tegra_spi_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(tegra_spi_suspend, tegra_spi_resume)
+};
+static struct platform_driver tegra_spi_driver = {
+	.driver = {
+		.name		= "spi-tegra114",
+		.owner		= THIS_MODULE,
+		.pm		= &tegra_spi_pm_ops,
+		.of_match_table	= tegra_spi_of_match,
+	},
+	.probe =	tegra_spi_probe,
+	.remove =	tegra_spi_remove,
+};
+module_platform_driver(tegra_spi_driver);
+
+MODULE_ALIAS("platform:spi-tegra114");
+MODULE_DESCRIPTION("NVIDIA Tegra114 SPI Controller Driver");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_LICENSE("GPL v2");