[PATCH] spi: tegra: add spi driver for sflash controller

[Laxman Dewangan]

Nvidia's Tegra20 have the SPI (SFLASH) controller to
interface with spi flash device which is used for system
boot. Add the spi driver for this controller.

Signed-off-by: Laxman Dewangan <ldewangan@xxxxxxxxxx>
---
 .../bindings/spi/nvidia,tegra20-sflash.txt         |   26 +
 drivers/spi/Kconfig                                |    8 +
 drivers/spi/Makefile                               |    1 +
 drivers/spi/spi-tegra20-sflash.c                   |  674 ++++++++++++++++++++
 4 files changed, 709 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/spi/nvidia,tegra20-sflash.txt
 create mode 100644 drivers/spi/spi-tegra20-sflash.c

diff --git a/Documentation/devicetree/bindings/spi/nvidia,tegra20-sflash.txt b/Documentation/devicetree/bindings/spi/nvidia,tegra20-sflash.txt
new file mode 100644
index 0000000..8cf24f6
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/nvidia,tegra20-sflash.txt
@@ -0,0 +1,26 @@
+NVIDIA Tegra20 SFLASH controller.
+
+Required properties:
+- compatible : should be "nvidia,tegra20-sflash".
+- reg: Should contain SFLASH registers location and length.
+- interrupts: Should contain SFLASH interrupts.
+- nvidia,dma-request-selector : The Tegra DMA controller's phandle and
+  request selector for this SFLASH controller.
+
+Recommended properties:
+- spi-max-frequency: Definition as per
+                     Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Example:
+
+spi@7000d600 {
+	compatible = "nvidia,tegra20-sflash";
+	reg = <0x7000c380 0x80>;
+	interrupts = <0 39 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 25290d9..3cbc9fb 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -385,6 +385,14 @@ config SPI_MXS
 	help
 	  SPI driver for Freescale MXS devices.
 
+config SPI_TEGRA20_SFLASH
+	tristate "Nvidia Tegra20 Serial flash Controller"
+	depends on ARCH_TEGRA
+	help
+	  SPI driver for Nvidia Tegra20 Serial flash Controller interface.
+	  The main usecase of this controller is to use spi flash as boot
+	  device.
+
 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 f87c0f1..9f6b3d8 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -60,6 +60,7 @@ 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_STMP3XXX)		+= spi-stmp.o
+obj-$(CONFIG_SPI_TEGRA20_SFLASH)	+= spi-tegra20-sflash.o
 obj-$(CONFIG_SPI_TEGRA20_SLINK)		+= spi-tegra20-slink.o
 obj-$(CONFIG_SPI_TI_SSP)		+= spi-ti-ssp.o
 obj-$(CONFIG_SPI_TLE62X0)		+= spi-tle62x0.o
diff --git a/drivers/spi/spi-tegra20-sflash.c b/drivers/spi/spi-tegra20-sflash.c
new file mode 100644
index 0000000..db7ddc9
--- /dev/null
+++ b/drivers/spi/spi-tegra20-sflash.c
@@ -0,0 +1,674 @@
+/*
+ * SPI driver for Nvidia's Tegra20 Serial Flash Controller.
+ *
+ * Copyright (c) 2012, 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/completion.h>
+#include <linux/delay.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>
+#include <linux/spi/spi-tegra.h>
+#include <mach/clk.h>
+
+#define SPI_COMMAND				0x000
+#define SPI_GO					BIT(30)
+#define SPI_M_S					BIT(28)
+#define SPI_ACTIVE_SCLK_MASK			(0x3 << 26)
+#define SPI_ACTIVE_SCLK_DRIVE_LOW		(0 << 26)
+#define SPI_ACTIVE_SCLK_DRIVE_HIGH		(1 << 26)
+#define SPI_ACTIVE_SCLK_PULL_LOW		(2 << 26)
+#define SPI_ACTIVE_SCLK_PULL_HIGH		(3 << 26)
+
+#define SPI_CK_SDA_FALLING			(1 << 21)
+#define SPI_CK_SDA_RISING			(0 << 21)
+#define SPI_CK_SDA_MASK				(1 << 21)
+#define SPI_ACTIVE_SDA				(0x3 << 18)
+#define SPI_ACTIVE_SDA_DRIVE_LOW		(0 << 18)
+#define SPI_ACTIVE_SDA_DRIVE_HIGH		(1 << 18)
+#define SPI_ACTIVE_SDA_PULL_LOW			(2 << 18)
+#define SPI_ACTIVE_SDA_PULL_HIGH		(3 << 18)
+
+#define SPI_CS_POL_INVERT			BIT(16)
+#define SPI_TX_EN				BIT(15)
+#define SPI_RX_EN				BIT(14)
+#define SPI_CS_VAL_HIGH				BIT(13)
+#define SPI_CS_VAL_LOW				0x0
+#define SPI_CS_SW				BIT(12)
+#define SPI_CS_HW				0x0
+#define SPI_CS_DELAY_MASK			(7 << 9)
+#define SPI_CS3_EN				BIT(8)
+#define SPI_CS2_EN				BIT(7)
+#define SPI_CS1_EN				BIT(6)
+#define SPI_CS0_EN				BIT(5)
+
+#define SPI_CS_MASK			(SPI_CS3_EN | SPI_CS2_EN |	\
+					SPI_CS1_EN | SPI_CS0_EN)
+#define SPI_BIT_LENGTH(x)		(((x) & 0x1f) << 0)
+
+#define SPI_MODES			(SPI_ACTIVE_SCLK_MASK | SPI_CK_SDA_MASK)
+
+#define SPI_STATUS			0x004
+#define SPI_BSY				BIT(31)
+#define SPI_RDY				BIT(30)
+#define SPI_TXF_FLUSH			BIT(29)
+#define SPI_RXF_FLUSH			BIT(28)
+#define SPI_RX_UNF			BIT(27)
+#define SPI_TX_OVF			BIT(26)
+#define SPI_RXF_EMPTY			BIT(25)
+#define SPI_RXF_FULL			BIT(24)
+#define SPI_TXF_EMPTY			BIT(23)
+#define SPI_TXF_FULL			BIT(22)
+#define SPI_BLK_CNT(count)		(((count) & 0xffff) + 1)
+
+#define SPI_FIFO_ERROR			(SPI_RX_UNF | SPI_TX_OVF)
+#define SPI_FIFO_EMPTY			(SPI_TX_EMPTY | SPI_RX_EMPTY)
+
+#define SPI_RX_CMP			0x8
+#define SPI_DMA_CTL			0x0C
+#define SPI_DMA_EN			BIT(31)
+#define SPI_IE_RXC			BIT(27)
+#define SPI_IE_TXC			BIT(26)
+#define SPI_PACKED			BIT(20)
+#define SPI_RX_TRIG_MASK		(0x3 << 18)
+#define SPI_RX_TRIG_1W			(0x0 << 18)
+#define SPI_RX_TRIG_4W			(0x1 << 18)
+#define SPI_TX_TRIG_MASK		(0x3 << 16)
+#define SPI_TX_TRIG_1W			(0x0 << 16)
+#define SPI_TX_TRIG_4W			(0x1 << 16)
+#define SPI_DMA_BLK_COUNT(count)	(((count) - 1) & 0xFFFF);
+
+#define SPI_TX_FIFO			0x10
+#define SPI_RX_FIFO			0x20
+
+#define DATA_DIR_TX			(1 << 0)
+#define DATA_DIR_RX			(1 << 1)
+
+#define MAX_CHIP_SELECT			4
+#define SPI_FIFO_DEPTH			4
+#define SPI_DMA_TIMEOUT               (msecs_to_jiffies(1000))
+
+struct tegra_sflash_data {
+	struct device				*dev;
+	struct spi_master			*master;
+	spinlock_t				lock;
+
+	struct clk				*clk;
+	void __iomem				*base;
+	unsigned				irq;
+	u32					spi_max_frequency;
+	u32					cur_speed;
+
+	struct spi_device			*cur_spi;
+	unsigned				cur_pos;
+	unsigned				cur_len;
+	unsigned				bytes_per_word;
+	unsigned				cur_direction;
+	unsigned				curr_xfer_words;
+
+	unsigned				cur_rx_pos;
+	unsigned				cur_tx_pos;
+
+	u32					tx_status;
+	u32					rx_status;
+	u32					status_reg;
+
+	u32					def_command_reg;
+	u32					command_reg;
+	u32					dma_control_reg;
+
+	struct completion			xfer_completion;
+	struct spi_transfer			*curr_xfer;
+};
+
+static int tegra_sflash_runtime_suspend(struct device *dev);
+static int tegra_sflash_runtime_resume(struct device *dev);
+
+static inline unsigned long tegra_sflash_readl(struct tegra_sflash_data *tsd,
+		unsigned long reg)
+{
+	return readl(tsd->base + reg);
+}
+
+static inline void tegra_sflash_writel(struct tegra_sflash_data *tsd,
+		unsigned long val, unsigned long reg)
+{
+	writel(val, tsd->base + reg);
+}
+
+static void tegra_sflash_clear_status(struct tegra_sflash_data *tsd)
+{
+	unsigned long val;
+	unsigned long val_write = 0;
+
+	val = tegra_sflash_readl(tsd, SPI_STATUS);
+
+	/* Write 1 to clear status register */
+	val_write = SPI_RDY | SPI_FIFO_ERROR;
+	tegra_sflash_writel(tsd, val_write, SPI_STATUS);
+}
+
+static unsigned tegra_sflash_calculate_curr_xfer_param(
+	struct spi_device *spi, struct tegra_sflash_data *tsd,
+	struct spi_transfer *t)
+{
+	unsigned remain_len = t->len - tsd->cur_pos;
+	unsigned max_word;
+
+	tsd->bytes_per_word = (t->bits_per_word - 1) / 8 + 1;
+	max_word = remain_len / tsd->bytes_per_word;
+	if (max_word > SPI_FIFO_DEPTH)
+		max_word = SPI_FIFO_DEPTH;
+	tsd->curr_xfer_words = max_word;
+	return max_word;
+}
+
+static unsigned tegra_sflash_fill_tx_fifo_from_client_txbuf(
+	struct tegra_sflash_data *tsd, struct spi_transfer *t)
+{
+	unsigned nbytes;
+	unsigned long status;
+	unsigned max_n_32bit = tsd->curr_xfer_words;
+	u8 *tx_buf = (u8 *)t->tx_buf + tsd->cur_tx_pos;
+
+	if (max_n_32bit > SPI_FIFO_DEPTH)
+		max_n_32bit = SPI_FIFO_DEPTH;
+	nbytes = max_n_32bit * tsd->bytes_per_word;
+
+	status = tegra_sflash_readl(tsd, SPI_STATUS);
+	while (!(status & SPI_TXF_FULL)) {
+		int i;
+		unsigned int x = 0;
+
+		for (i = 0; nbytes && (i < tsd->bytes_per_word);
+							i++, nbytes--)
+				x |= ((*tx_buf++) << i*8);
+		tegra_sflash_writel(tsd, x, SPI_TX_FIFO);
+		if (!nbytes)
+			break;
+
+		status = tegra_sflash_readl(tsd, SPI_STATUS);
+	}
+	tsd->cur_tx_pos += max_n_32bit * tsd->bytes_per_word;
+	return max_n_32bit;
+}
+
+static int tegra_sflash_read_rx_fifo_to_client_rxbuf(
+		struct tegra_sflash_data *tsd, struct spi_transfer *t)
+{
+	unsigned long status;
+	unsigned int read_words = 0;
+	u8 *rx_buf = (u8 *)t->rx_buf + tsd->cur_rx_pos;
+
+	status = tegra_sflash_readl(tsd, SPI_STATUS);
+	while (!(status & SPI_RXF_EMPTY)) {
+		int i;
+		unsigned long x;
+
+		x = tegra_sflash_readl(tsd, SPI_RX_FIFO);
+		for (i = 0; (i < tsd->bytes_per_word); i++)
+			*rx_buf++ = (x >> (i*8)) & 0xFF;
+		read_words++;
+		status = tegra_sflash_readl(tsd, SPI_STATUS);
+	}
+	tsd->cur_rx_pos += read_words * tsd->bytes_per_word;
+	return 0;
+}
+
+static int tegra_sflash_start_cpu_based_transfer(
+		struct tegra_sflash_data *tsd, struct spi_transfer *t)
+{
+	unsigned long val = 0;
+	unsigned cur_words;
+
+	if (tsd->cur_direction & DATA_DIR_TX)
+		val |= SPI_IE_TXC;
+
+	if (tsd->cur_direction & DATA_DIR_RX)
+		val |= SPI_IE_RXC;
+
+	tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
+	tsd->dma_control_reg = val;
+
+	if (tsd->cur_direction & DATA_DIR_TX)
+		cur_words = tegra_sflash_fill_tx_fifo_from_client_txbuf(tsd, t);
+	else
+		cur_words = tsd->curr_xfer_words;
+	val |= SPI_DMA_BLK_COUNT(cur_words);
+	tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
+	tsd->dma_control_reg = val;
+	val |= SPI_DMA_EN;
+	tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
+	return 0;
+}
+
+static int tegra_sflash_start_transfer_one(struct spi_device *spi,
+		struct spi_transfer *t, bool is_first_of_msg,
+		bool is_single_xfer)
+{
+	struct tegra_sflash_data *tsd = spi_master_get_devdata(spi->master);
+	u32 speed;
+	unsigned long command;
+
+	speed = t->speed_hz ? t->speed_hz : spi->max_speed_hz;
+	if (!speed)
+		speed = tsd->spi_max_frequency;
+	if (speed != tsd->cur_speed) {
+		clk_set_rate(tsd->clk, speed);
+		tsd->cur_speed = speed;
+	}
+
+	tsd->cur_spi = spi;
+	tsd->cur_pos = 0;
+	tsd->cur_rx_pos = 0;
+	tsd->cur_tx_pos = 0;
+	tsd->curr_xfer = t;
+	tegra_sflash_calculate_curr_xfer_param(spi, tsd, t);
+	if (is_first_of_msg) {
+		command = tsd->def_command_reg;
+		command |= SPI_BIT_LENGTH(t->bits_per_word - 1);
+		command |= SPI_CS_VAL_HIGH;
+
+		command &= ~SPI_MODES;
+		if (spi->mode & SPI_CPHA)
+			command |= SPI_CK_SDA_FALLING;
+
+		if (spi->mode & SPI_CPOL)
+			command |= SPI_ACTIVE_SCLK_DRIVE_HIGH;
+		else
+			command |= SPI_ACTIVE_SCLK_DRIVE_LOW;
+		command |= SPI_CS0_EN << spi->chip_select;
+	} else {
+		command = tsd->command_reg;
+		command &= ~SPI_BIT_LENGTH(~0);
+		command |= SPI_BIT_LENGTH(t->bits_per_word - 1);
+		command &= ~(SPI_RX_EN | SPI_TX_EN);
+	}
+
+	tsd->cur_direction = 0;
+	if (t->rx_buf) {
+		command |= SPI_RX_EN;
+		tsd->cur_direction |= DATA_DIR_RX;
+	}
+	if (t->tx_buf) {
+		command |= SPI_TX_EN;
+		tsd->cur_direction |= DATA_DIR_TX;
+	}
+	tegra_sflash_writel(tsd, command, SPI_COMMAND);
+	tsd->command_reg = command;
+
+	return  tegra_sflash_start_cpu_based_transfer(tsd, t);
+}
+
+static int tegra_sflash_transfer_one_message(struct spi_master *master,
+			struct spi_message *msg)
+{
+	bool is_first_msg = true;
+	int single_xfer;
+	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
+	struct spi_transfer *xfer;
+	struct spi_device *spi = msg->spi;
+	int ret;
+
+	ret = pm_runtime_get_sync(tsd->dev);
+	if (ret < 0) {
+		dev_err(tsd->dev, "pm_runtime_get() failed, err = %d\n", ret);
+		return ret;
+	}
+
+	msg->status = 0;
+	msg->actual_length = 0;
+	single_xfer = list_is_singular(&msg->transfers);
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		INIT_COMPLETION(tsd->xfer_completion);
+		ret = tegra_sflash_start_transfer_one(spi, xfer,
+					is_first_msg, single_xfer);
+		if (ret < 0) {
+			dev_err(tsd->dev,
+				"spi can not start transfer, err %d\n", ret);
+			goto exit;
+		}
+		is_first_msg = false;
+		ret = wait_for_completion_timeout(&tsd->xfer_completion,
+						SPI_DMA_TIMEOUT);
+		if (WARN_ON(ret == 0)) {
+			dev_err(tsd->dev,
+				"spi trasfer timeout, err %d\n", ret);
+			ret = -EIO;
+			goto exit;
+		}
+
+		if (tsd->tx_status ||  tsd->rx_status) {
+			dev_err(tsd->dev, "Error in Transfer\n");
+			ret = -EIO;
+			goto exit;
+		}
+		msg->actual_length += xfer->len;
+		if (xfer->cs_change && xfer->delay_usecs) {
+			tegra_sflash_writel(tsd, tsd->def_command_reg,
+					SPI_COMMAND);
+			udelay(xfer->delay_usecs);
+		}
+	}
+	ret = 0;
+exit:
+	tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND);
+	msg->status = ret;
+	spi_finalize_current_message(master);
+	pm_runtime_put(tsd->dev);
+	return ret;
+}
+
+static irqreturn_t handle_cpu_based_xfer(struct tegra_sflash_data *tsd)
+{
+	struct spi_transfer *t = tsd->curr_xfer;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tsd->lock, flags);
+	if (tsd->tx_status ||  tsd->rx_status ||
+				(tsd->status_reg & SPI_BSY)) {
+		dev_err(tsd->dev,
+			"CpuXfer ERROR bit set 0x%x\n", tsd->status_reg);
+		dev_err(tsd->dev,
+			"CpuXfer 0x%08x:0x%08x\n", tsd->command_reg,
+				tsd->dma_control_reg);
+		tegra_periph_reset_assert(tsd->clk);
+		udelay(2);
+		tegra_periph_reset_deassert(tsd->clk);
+		complete(&tsd->xfer_completion);
+		goto exit;
+	}
+
+	if (tsd->cur_direction & DATA_DIR_RX)
+		tegra_sflash_read_rx_fifo_to_client_rxbuf(tsd, t);
+
+	if (tsd->cur_direction & DATA_DIR_TX)
+		tsd->cur_pos = tsd->cur_tx_pos;
+	else
+		tsd->cur_pos = tsd->cur_rx_pos;
+
+	if (tsd->cur_pos == t->len) {
+		complete(&tsd->xfer_completion);
+		goto exit;
+	}
+
+	tegra_sflash_calculate_curr_xfer_param(tsd->cur_spi, tsd, t);
+	tegra_sflash_start_cpu_based_transfer(tsd, t);
+exit:
+	spin_unlock_irqrestore(&tsd->lock, flags);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t tegra_sflash_isr(int irq, void *context_data)
+{
+	struct tegra_sflash_data *tsd = context_data;
+
+	tsd->status_reg = tegra_sflash_readl(tsd, SPI_STATUS);
+	if (tsd->cur_direction & DATA_DIR_TX)
+		tsd->tx_status = tsd->status_reg & SPI_TX_OVF;
+
+	if (tsd->cur_direction & DATA_DIR_RX)
+		tsd->rx_status = tsd->status_reg & SPI_RX_UNF;
+	tegra_sflash_clear_status(tsd);
+
+	return handle_cpu_based_xfer(tsd);
+}
+
+static struct tegra_spi_platform_data *tegra_sflash_parse_dt(
+		struct platform_device *pdev)
+{
+	struct tegra_spi_platform_data *pdata;
+	const unsigned int *prop;
+	struct device_node *np = pdev->dev.of_node;
+
+	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata) {
+		dev_err(&pdev->dev, "Memory alloc for pdata failed\n");
+		return NULL;
+	}
+
+	prop = of_get_property(np, "spi-max-frequency", NULL);
+	if (prop)
+		pdata->spi_max_frequency = be32_to_cpup(prop);
+
+	return pdata;
+}
+
+static struct of_device_id tegra_sflash_of_match[] __devinitconst = {
+	{ .compatible = "nvidia,tegra20-sflash", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, tegra_sflash_of_match);
+
+static int __devinit tegra_sflash_probe(struct platform_device *pdev)
+{
+	struct spi_master	*master;
+	struct tegra_sflash_data	*tsd;
+	struct resource		*r;
+	struct tegra_spi_platform_data *pdata = pdev->dev.platform_data;
+	int ret;
+	const struct of_device_id *match;
+
+	match = of_match_device(of_match_ptr(tegra_sflash_of_match),
+					&pdev->dev);
+	if (!match) {
+		dev_err(&pdev->dev, "Error: No device match found\n");
+		return -ENODEV;
+	}
+
+	if (!pdata && pdev->dev.of_node)
+		pdata = tegra_sflash_parse_dt(pdev);
+
+	if (!pdata) {
+		dev_err(&pdev->dev, "No platform data, exiting\n");
+		return -ENODEV;
+	}
+
+	if (!pdata->spi_max_frequency)
+		pdata->spi_max_frequency = 25000000; /* 25MHz */
+
+	master = spi_alloc_master(&pdev->dev, sizeof(*tsd));
+	if (!master) {
+		dev_err(&pdev->dev, "master allocation failed\n");
+		return -ENOMEM;
+	}
+
+	/* the spi->mode bits understood by this driver: */
+	master->mode_bits = SPI_CPOL | SPI_CPHA;
+	master->transfer_one_message = tegra_sflash_transfer_one_message;
+	master->num_chipselect = MAX_CHIP_SELECT;
+	master->bus_num = -1;
+
+	dev_set_drvdata(&pdev->dev, master);
+	tsd = spi_master_get_devdata(master);
+	tsd->master = master;
+	tsd->dev = &pdev->dev;
+	spin_lock_init(&tsd->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;
+	}
+	tsd->base = devm_request_and_ioremap(&pdev->dev, r);
+	if (!tsd->base) {
+		dev_err(&pdev->dev,
+			"Cannot request memregion/iomap dma address\n");
+		ret = -EADDRNOTAVAIL;
+		goto exit_free_master;
+	}
+
+	tsd->irq = platform_get_irq(pdev, 0);
+	ret = request_irq(tsd->irq, tegra_sflash_isr, 0,
+			dev_name(&pdev->dev), tsd);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n",
+					tsd->irq);
+		goto exit_free_master;
+	}
+
+	tsd->clk = devm_clk_get(&pdev->dev, "spi");
+	if (IS_ERR(tsd->clk)) {
+		dev_err(&pdev->dev, "can not get clock\n");
+		ret = PTR_ERR(tsd->clk);
+		goto exit_free_irq;
+	}
+
+
+	tsd->spi_max_frequency = pdata->spi_max_frequency;
+
+	init_completion(&tsd->xfer_completion);
+
+	pm_runtime_enable(&pdev->dev);
+	if (!pm_runtime_enabled(&pdev->dev)) {
+		ret = tegra_sflash_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;
+	}
+
+	/* Reset controller */
+	tegra_periph_reset_assert(tsd->clk);
+	udelay(2);
+	tegra_periph_reset_deassert(tsd->clk);
+
+	tsd->def_command_reg  = SPI_M_S | SPI_CS_SW;
+	tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND);
+	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_sflash_runtime_suspend(&pdev->dev);
+exit_free_irq:
+	free_irq(tsd->irq, tsd);
+exit_free_master:
+	spi_master_put(master);
+	return ret;
+}
+
+static int __devexit tegra_sflash_remove(struct platform_device *pdev)
+{
+	struct spi_master *master = dev_get_drvdata(&pdev->dev);
+	struct tegra_sflash_data	*tsd = spi_master_get_devdata(master);
+
+	free_irq(tsd->irq, tsd);
+	spi_unregister_master(master);
+
+	pm_runtime_disable(&pdev->dev);
+	if (!pm_runtime_status_suspended(&pdev->dev))
+		tegra_sflash_runtime_suspend(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tegra_sflash_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+
+	return spi_master_suspend(master);
+}
+
+static int tegra_sflash_resume(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct tegra_sflash_data *tsd = 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_sflash_writel(tsd, tsd->command_reg, SPI_COMMAND);
+	pm_runtime_put(dev);
+
+	return spi_master_resume(master);
+}
+#endif
+
+static int tegra_sflash_runtime_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
+
+	/* Flush all write which are in PPSB queue by reading back */
+	tegra_sflash_readl(tsd, SPI_COMMAND);
+
+	clk_disable_unprepare(tsd->clk);
+	return 0;
+}
+
+static int tegra_sflash_runtime_resume(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
+	int ret;
+
+	ret = clk_prepare_enable(tsd->clk);
+	if (ret < 0) {
+		dev_err(tsd->dev, "clk_prepare failed: %d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+static const struct dev_pm_ops slink_pm_ops = {
+	SET_RUNTIME_PM_OPS(tegra_sflash_runtime_suspend,
+		tegra_sflash_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(tegra_sflash_suspend, tegra_sflash_resume)
+};
+static struct platform_driver tegra_sflash_driver = {
+	.driver = {
+		.name		= "spi-tegra-sflash",
+		.owner		= THIS_MODULE,
+		.pm		= &slink_pm_ops,
+		.of_match_table	= of_match_ptr(tegra_sflash_of_match),
+	},
+	.probe =	tegra_sflash_probe,
+	.remove =	__devexit_p(tegra_sflash_remove),
+};
+module_platform_driver(tegra_sflash_driver);
+
+MODULE_ALIAS("platform:spi-tegra-sflash");
+MODULE_DESCRIPTION("NVIDIA Tegra20 Serial Flash Controller Driver");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@xxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
-- 
1.7.1.1

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