Patchwork [V2] spi: tegra114: add spi driver

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Submitter Laxman Dewangan
Date Feb. 21, 2013, 7:10 a.m.
Message ID <1361430631-18894-1-git-send-email-ldewangan@nvidia.com>
Download mbox | patch
Permalink /patch/222193/
State Not Applicable, archived
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Comments

Laxman Dewangan - Feb. 21, 2013, 7:10 a.m.
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 lager 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>
---
Changes from V1:
- All nit cleanups for nomenclature like Nvidia to NVIDIA, spi to SPI etc.
- remove bits_per_word check as all transfer have this valid parameter.
- Cleanups in dt parsing and remove dt node validity.
- use devm_ioremap_resource for mapping physical address.

 .../bindings/spi/nvidia,tegra114-spi.txt           |   25 +
 drivers/spi/Kconfig                                |    8 +
 drivers/spi/Makefile                               |    1 +
 drivers/spi/spi-tegra114.c                         | 1246 ++++++++++++++++++++
 4 files changed, 1280 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/spi/nvidia,tegra114-spi.txt
 create mode 100644 drivers/spi/spi-tegra114.c
Stephen Warren - Feb. 21, 2013, 7:15 p.m.
On 02/21/2013 12:10 AM, Laxman Dewangan wrote:
> 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.

Looks good. Just a couple of nits mentioned below, then,
Reviewed-by: Stephen Warren <swarren@nvidia.com>

Note: There are a few minor diffs between this file and
spi-tegra20-slink.c. It might be worth eliminating as many as possible,
perhaps in a followon patch.

> diff --git a/Documentation/devicetree/bindings/spi/nvidia,tegra114-spi.txt b/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.

The binding should specify that a clock named "spi" needs to be
provided, using the standard properties in ../clock/clock-bindings.txt

> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile

>  obj-$(CONFIG_SPI_SIRF)		+= spi-sirf.o
>  obj-$(CONFIG_SPI_TEGRA20_SFLASH)	+= spi-tegra20-sflash.o
>  obj-$(CONFIG_SPI_TEGRA20_SLINK)		+= spi-tegra20-slink.o
> +obj-$(CONFIG_SPI_TEGRA114)		+= spi-tegra114.o

While Tegra114 is newer, it should really be listed before the Tegra20
entries, since the Makefile is alpha-numerically sorted right now I believe.

> diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c

> +static struct platform_driver tegra_spi_driver = {
> +	.driver = {
> +		.name		= "spi-tegra114",
> +		.owner		= THIS_MODULE,
> +		.pm		= &tegra_spi_pm_ops,
> +		.of_match_table	= of_match_ptr(tegra_spi_of_match),

No need to use of_match_ptr() there; just use the raw value since
CONFIG_OF is guaranteed to be enabled.
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Patch

diff --git a/Documentation/devicetree/bindings/spi/nvidia,tegra114-spi.txt b/Documentation/devicetree/bindings/spi/nvidia,tegra114-spi.txt
new file mode 100644
index 0000000..c6457e9
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/nvidia,tegra114-spi.txt
@@ -0,0 +1,25 @@ 
+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.
+
+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";
+};
+
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index f80eee7..10699bb 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -405,6 +405,14 @@  config SPI_TEGRA20_SFLASH
 	  The main usecase of this controller is to use spi flash as boot
 	  device.
 
+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_SLINK
 	tristate "Nvidia Tegra20/Tegra30 SLINK Controller"
 	depends on ARCH_TEGRA && TEGRA20_APB_DMA
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index e53c309..ee2a119 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -65,6 +65,7 @@  obj-$(CONFIG_SPI_SH_SCI)		+= spi-sh-sci.o
 obj-$(CONFIG_SPI_SIRF)		+= spi-sirf.o
 obj-$(CONFIG_SPI_TEGRA20_SFLASH)	+= spi-tegra20-sflash.o
 obj-$(CONFIG_SPI_TEGRA20_SLINK)		+= spi-tegra20-slink.o
+obj-$(CONFIG_SPI_TEGRA114)		+= spi-tegra114.o
 obj-$(CONFIG_SPI_TI_SSP)		+= spi-ti-ssp.o
 obj-$(CONFIG_SPI_TLE62X0)		+= spi-tle62x0.o
 obj-$(CONFIG_SPI_TOPCLIFF_PCH)		+= spi-topcliff-pch.o
diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c
new file mode 100644
index 0000000..35b1e94
--- /dev/null
+++ b/drivers/spi/spi-tegra114.c
@@ -0,0 +1,1246 @@ 
+/*
+ * 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	= of_match_ptr(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");