[linux-2.6-block.git] / drivers / spi / spi-tegra20-sflash.c

/*
 * SPI driver for Nvidia's Tegra20 Serial Flash Controller.
 *
 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
 *
 * Author: Laxman Dewangan <ldewangan@nvidia.com>
 *
 * 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/clk/tegra.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)
{
	/* Write 1 to clear status register */
	tegra_sflash_writel(tsd, SPI_RDY | SPI_FIFO_ERROR, 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 = DIV_ROUND_UP(t->bits_per_word, 8);
	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;
	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_setup(struct spi_device *spi)
{
	struct tegra_sflash_data *tsd = spi_master_get_devdata(spi->master);

	/* Set speed to the spi max fequency if spi device has not set */
	spi->max_speed_hz = spi->max_speed_hz ? : tsd->spi_max_frequency;
	return 0;
}

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;

	msg->status = 0;
	msg->actual_length = 0;
	single_xfer = list_is_singular(&msg->transfers);
	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
		reinit_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);
	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 void tegra_sflash_parse_dt(struct tegra_sflash_data *tsd)
{
	struct device_node *np = tsd->dev->of_node;

	if (of_property_read_u32(np, "spi-max-frequency",
					&tsd->spi_max_frequency))
		tsd->spi_max_frequency = 25000000; /* 25MHz */
}

static struct of_device_id tegra_sflash_of_match[] = {
	{ .compatible = "nvidia,tegra20-sflash", },
	{}
};
MODULE_DEVICE_TABLE(of, tegra_sflash_of_match);

static int tegra_sflash_probe(struct platform_device *pdev)
{
	struct spi_master	*master;
	struct tegra_sflash_data	*tsd;
	struct resource		*r;
	int ret;
	const struct of_device_id *match;

	match = of_match_device(tegra_sflash_of_match, &pdev->dev);
	if (!match) {
		dev_err(&pdev->dev, "Error: No device match found\n");
		return -ENODEV;
	}

	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->setup = tegra_sflash_setup;
	master->transfer_one_message = tegra_sflash_transfer_one_message;
	master->auto_runtime_pm = true;
	master->num_chipselect = MAX_CHIP_SELECT;
	master->bus_num = -1;

	platform_set_drvdata(pdev, master);
	tsd = spi_master_get_devdata(master);
	tsd->master = master;
	tsd->dev = &pdev->dev;
	spin_lock_init(&tsd->lock);

	tegra_sflash_parse_dt(tsd);

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	tsd->base = devm_ioremap_resource(&pdev->dev, r);
	if (IS_ERR(tsd->base)) {
		ret = PTR_ERR(tsd->base);
		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, NULL);
	if (IS_ERR(tsd->clk)) {
		dev_err(&pdev->dev, "can not get clock\n");
		ret = PTR_ERR(tsd->clk);
		goto exit_free_irq;
	}

	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 = devm_spi_register_master(&pdev->dev, 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 tegra_sflash_remove(struct platform_device *pdev)
{
	struct spi_master *master = platform_get_drvdata(pdev);
	struct tegra_sflash_data	*tsd = spi_master_get_devdata(master);

	free_irq(tsd->irq, tsd);

	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	= tegra_sflash_of_match,
	},
	.probe =	tegra_sflash_probe,
	.remove =	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@nvidia.com>");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
8528547b LD	1	/*
	2	* SPI driver for Nvidia's Tegra20 Serial Flash Controller.
	3	*
	4	* Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
	5	*
	6	* Author: Laxman Dewangan <ldewangan@nvidia.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify it
	9	* under the terms and conditions of the GNU General Public License,
	10	* version 2, as published by the Free Software Foundation.
	11	*
	12	* This program is distributed in the hope it will be useful, but WITHOUT
	13	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	14	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	15	* more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	19	*/
	20
	21	#include <linux/clk.h>
	22	#include <linux/completion.h>
	23	#include <linux/delay.h>
	24	#include <linux/err.h>
	25	#include <linux/init.h>
	26	#include <linux/interrupt.h>
	27	#include <linux/io.h>
	28	#include <linux/kernel.h>
	29	#include <linux/kthread.h>
	30	#include <linux/module.h>
	31	#include <linux/platform_device.h>
	32	#include <linux/pm_runtime.h>
	33	#include <linux/of.h>
	34	#include <linux/of_device.h>
	35	#include <linux/spi/spi.h>
61fd290d	36	#include <linux/clk/tegra.h>
8528547b LD	37
	38	#define SPI_COMMAND 0x000
	39	#define SPI_GO BIT(30)
	40	#define SPI_M_S BIT(28)
	41	#define SPI_ACTIVE_SCLK_MASK (0x3 << 26)
	42	#define SPI_ACTIVE_SCLK_DRIVE_LOW (0 << 26)
	43	#define SPI_ACTIVE_SCLK_DRIVE_HIGH (1 << 26)
	44	#define SPI_ACTIVE_SCLK_PULL_LOW (2 << 26)
	45	#define SPI_ACTIVE_SCLK_PULL_HIGH (3 << 26)
	46
	47	#define SPI_CK_SDA_FALLING (1 << 21)
	48	#define SPI_CK_SDA_RISING (0 << 21)
	49	#define SPI_CK_SDA_MASK (1 << 21)
	50	#define SPI_ACTIVE_SDA (0x3 << 18)
	51	#define SPI_ACTIVE_SDA_DRIVE_LOW (0 << 18)
	52	#define SPI_ACTIVE_SDA_DRIVE_HIGH (1 << 18)
	53	#define SPI_ACTIVE_SDA_PULL_LOW (2 << 18)
	54	#define SPI_ACTIVE_SDA_PULL_HIGH (3 << 18)
	55
	56	#define SPI_CS_POL_INVERT BIT(16)
	57	#define SPI_TX_EN BIT(15)
	58	#define SPI_RX_EN BIT(14)
	59	#define SPI_CS_VAL_HIGH BIT(13)
	60	#define SPI_CS_VAL_LOW 0x0
	61	#define SPI_CS_SW BIT(12)
	62	#define SPI_CS_HW 0x0
	63	#define SPI_CS_DELAY_MASK (7 << 9)
	64	#define SPI_CS3_EN BIT(8)
	65	#define SPI_CS2_EN BIT(7)
	66	#define SPI_CS1_EN BIT(6)
	67	#define SPI_CS0_EN BIT(5)
	68
	69	#define SPI_CS_MASK (SPI_CS3_EN \| SPI_CS2_EN \| \
	70	SPI_CS1_EN \| SPI_CS0_EN)
	71	#define SPI_BIT_LENGTH(x) (((x) & 0x1f) << 0)
	72
	73	#define SPI_MODES (SPI_ACTIVE_SCLK_MASK \| SPI_CK_SDA_MASK)
	74
	75	#define SPI_STATUS 0x004
	76	#define SPI_BSY BIT(31)
	77	#define SPI_RDY BIT(30)
	78	#define SPI_TXF_FLUSH BIT(29)
	79	#define SPI_RXF_FLUSH BIT(28)
	80	#define SPI_RX_UNF BIT(27)
	81	#define SPI_TX_OVF BIT(26)
	82	#define SPI_RXF_EMPTY BIT(25)
	83	#define SPI_RXF_FULL BIT(24)
	84	#define SPI_TXF_EMPTY BIT(23)
	85	#define SPI_TXF_FULL BIT(22)
	86	#define SPI_BLK_CNT(count) (((count) & 0xffff) + 1)
	87
	88	#define SPI_FIFO_ERROR (SPI_RX_UNF \| SPI_TX_OVF)
	89	#define SPI_FIFO_EMPTY (SPI_TX_EMPTY \| SPI_RX_EMPTY)
	90
	91	#define SPI_RX_CMP 0x8
	92	#define SPI_DMA_CTL 0x0C
	93	#define SPI_DMA_EN BIT(31)
	94	#define SPI_IE_RXC BIT(27)
	95	#define SPI_IE_TXC BIT(26)
	96	#define SPI_PACKED BIT(20)
	97	#define SPI_RX_TRIG_MASK (0x3 << 18)
	98	#define SPI_RX_TRIG_1W (0x0 << 18)
	99	#define SPI_RX_TRIG_4W (0x1 << 18)
	100	#define SPI_TX_TRIG_MASK (0x3 << 16)
101	#define SPI_TX_TRIG_1W (0x0 << 16)
102	#define SPI_TX_TRIG_4W (0x1 << 16)
103	#define SPI_DMA_BLK_COUNT(count) (((count) - 1) & 0xFFFF);
104
105	#define SPI_TX_FIFO 0x10
106	#define SPI_RX_FIFO 0x20
107
108	#define DATA_DIR_TX (1 << 0)
109	#define DATA_DIR_RX (1 << 1)
110
111	#define MAX_CHIP_SELECT 4
112	#define SPI_FIFO_DEPTH 4
113	#define SPI_DMA_TIMEOUT (msecs_to_jiffies(1000))
114
115	struct tegra_sflash_data {
116	struct device *dev;
117	struct spi_master *master;
118	spinlock_t lock;
119
120	struct clk *clk;
121	void __iomem *base;
122	unsigned irq;
123	u32 spi_max_frequency;
124	u32 cur_speed;
125
126	struct spi_device *cur_spi;
127	unsigned cur_pos;
128	unsigned cur_len;
129	unsigned bytes_per_word;
130	unsigned cur_direction;
131	unsigned curr_xfer_words;
132
133	unsigned cur_rx_pos;
134	unsigned cur_tx_pos;
135
136	u32 tx_status;
137	u32 rx_status;
138	u32 status_reg;
139
140	u32 def_command_reg;
141	u32 command_reg;
142	u32 dma_control_reg;
143
144	struct completion xfer_completion;
145	struct spi_transfer *curr_xfer;
146	};
147
148	static int tegra_sflash_runtime_suspend(struct device *dev);
149	static int tegra_sflash_runtime_resume(struct device *dev);
150
151	static inline unsigned long tegra_sflash_readl(struct tegra_sflash_data *tsd,
152	unsigned long reg)
153	{
154	return readl(tsd->base + reg);
155	}
156
157	static inline void tegra_sflash_writel(struct tegra_sflash_data *tsd,
158	unsigned long val, unsigned long reg)
159	{
160	writel(val, tsd->base + reg);
161	}
162
163	static void tegra_sflash_clear_status(struct tegra_sflash_data *tsd)
164	{
165	/* Write 1 to clear status register */
166	tegra_sflash_writel(tsd, SPI_RDY \| SPI_FIFO_ERROR, SPI_STATUS);
167	}
168
169	static unsigned tegra_sflash_calculate_curr_xfer_param(
170	struct spi_device spi, struct tegra_sflash_data tsd,
171	struct spi_transfer *t)
172	{
173	unsigned remain_len = t->len - tsd->cur_pos;
174	unsigned max_word;
175
e91d2352	176	tsd->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8);
8528547b LD	177	max_word = remain_len / tsd->bytes_per_word;
	178	if (max_word > SPI_FIFO_DEPTH)
	179	max_word = SPI_FIFO_DEPTH;
	180	tsd->curr_xfer_words = max_word;
	181	return max_word;
	182	}
	183
	184	static unsigned tegra_sflash_fill_tx_fifo_from_client_txbuf(
	185	struct tegra_sflash_data tsd, struct spi_transfer t)
	186	{
	187	unsigned nbytes;
	188	unsigned long status;
	189	unsigned max_n_32bit = tsd->curr_xfer_words;
	190	u8 tx_buf = (u8 )t->tx_buf + tsd->cur_tx_pos;
	191
	192	if (max_n_32bit > SPI_FIFO_DEPTH)
	193	max_n_32bit = SPI_FIFO_DEPTH;
	194	nbytes = max_n_32bit * tsd->bytes_per_word;
	195
	196	status = tegra_sflash_readl(tsd, SPI_STATUS);
	197	while (!(status & SPI_TXF_FULL)) {
	198	int i;
	199	unsigned int x = 0;
	200
	201	for (i = 0; nbytes && (i < tsd->bytes_per_word);
	202	i++, nbytes--)
	203	x \|= ((tx_buf++) << i8);
	204	tegra_sflash_writel(tsd, x, SPI_TX_FIFO);
	205	if (!nbytes)
	206	break;
	207
	208	status = tegra_sflash_readl(tsd, SPI_STATUS);
	209	}
	210	tsd->cur_tx_pos += max_n_32bit * tsd->bytes_per_word;
	211	return max_n_32bit;
	212	}
	213
	214	static int tegra_sflash_read_rx_fifo_to_client_rxbuf(
	215	struct tegra_sflash_data tsd, struct spi_transfer t)
	216	{
	217	unsigned long status;
	218	unsigned int read_words = 0;
	219	u8 rx_buf = (u8 )t->rx_buf + tsd->cur_rx_pos;
	220
	221	status = tegra_sflash_readl(tsd, SPI_STATUS);
	222	while (!(status & SPI_RXF_EMPTY)) {
	223	int i;
	224	unsigned long x;
	225
	226	x = tegra_sflash_readl(tsd, SPI_RX_FIFO);
	227	for (i = 0; (i < tsd->bytes_per_word); i++)
	228	rx_buf++ = (x >> (i8)) & 0xFF;
	229	read_words++;
	230	status = tegra_sflash_readl(tsd, SPI_STATUS);
	231	}
	232	tsd->cur_rx_pos += read_words * tsd->bytes_per_word;
	233	return 0;
	234	}
	235
	236	static int tegra_sflash_start_cpu_based_transfer(
	237	struct tegra_sflash_data tsd, struct spi_transfer t)
	238	{
	239	unsigned long val = 0;
	240	unsigned cur_words;
241
242	if (tsd->cur_direction & DATA_DIR_TX)
243	val \|= SPI_IE_TXC;
244
245	if (tsd->cur_direction & DATA_DIR_RX)
246	val \|= SPI_IE_RXC;
247
248	tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
249	tsd->dma_control_reg = val;
250
251	if (tsd->cur_direction & DATA_DIR_TX)
252	cur_words = tegra_sflash_fill_tx_fifo_from_client_txbuf(tsd, t);
253	else
254	cur_words = tsd->curr_xfer_words;
255	val \|= SPI_DMA_BLK_COUNT(cur_words);
256	tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
257	tsd->dma_control_reg = val;
258	val \|= SPI_DMA_EN;
259	tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
260	return 0;
261	}
262
263	static int tegra_sflash_start_transfer_one(struct spi_device *spi,
264	struct spi_transfer *t, bool is_first_of_msg,
265	bool is_single_xfer)
266	{
267	struct tegra_sflash_data *tsd = spi_master_get_devdata(spi->master);
268	u32 speed;
269	unsigned long command;
270
beb96c2a	271	speed = t->speed_hz;
8528547b LD	272	if (speed != tsd->cur_speed) {
	273	clk_set_rate(tsd->clk, speed);
	274	tsd->cur_speed = speed;
	275	}
	276
	277	tsd->cur_spi = spi;
	278	tsd->cur_pos = 0;
	279	tsd->cur_rx_pos = 0;
	280	tsd->cur_tx_pos = 0;
	281	tsd->curr_xfer = t;
	282	tegra_sflash_calculate_curr_xfer_param(spi, tsd, t);
	283	if (is_first_of_msg) {
	284	command = tsd->def_command_reg;
	285	command \|= SPI_BIT_LENGTH(t->bits_per_word - 1);
	286	command \|= SPI_CS_VAL_HIGH;
	287
	288	command &= ~SPI_MODES;
	289	if (spi->mode & SPI_CPHA)
	290	command \|= SPI_CK_SDA_FALLING;
	291
	292	if (spi->mode & SPI_CPOL)
	293	command \|= SPI_ACTIVE_SCLK_DRIVE_HIGH;
	294	else
	295	command \|= SPI_ACTIVE_SCLK_DRIVE_LOW;
	296	command \|= SPI_CS0_EN << spi->chip_select;
	297	} else {
	298	command = tsd->command_reg;
	299	command &= ~SPI_BIT_LENGTH(~0);
	300	command \|= SPI_BIT_LENGTH(t->bits_per_word - 1);
	301	command &= ~(SPI_RX_EN \| SPI_TX_EN);
	302	}
	303
	304	tsd->cur_direction = 0;
	305	if (t->rx_buf) {
	306	command \|= SPI_RX_EN;
	307	tsd->cur_direction \|= DATA_DIR_RX;
	308	}
	309	if (t->tx_buf) {
	310	command \|= SPI_TX_EN;
	311	tsd->cur_direction \|= DATA_DIR_TX;
	312	}
	313	tegra_sflash_writel(tsd, command, SPI_COMMAND);
	314	tsd->command_reg = command;
	315
	316	return tegra_sflash_start_cpu_based_transfer(tsd, t);
	317	}
	318
beb96c2a LD	319	static int tegra_sflash_setup(struct spi_device *spi)
	320	{
	321	struct tegra_sflash_data *tsd = spi_master_get_devdata(spi->master);
	322
	323	/* Set speed to the spi max fequency if spi device has not set */
	324	spi->max_speed_hz = spi->max_speed_hz ? : tsd->spi_max_frequency;
	325	return 0;
	326	}
	327
8528547b LD	328	static int tegra_sflash_transfer_one_message(struct spi_master *master,
	329	struct spi_message *msg)
	330	{
	331	bool is_first_msg = true;
	332	int single_xfer;
	333	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
	334	struct spi_transfer *xfer;
	335	struct spi_device *spi = msg->spi;
	336	int ret;
	337
8528547b LD	338	msg->status = 0;
	339	msg->actual_length = 0;
	340	single_xfer = list_is_singular(&msg->transfers);
	341	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
16735d02	342	reinit_completion(&tsd->xfer_completion);
8528547b LD	343	ret = tegra_sflash_start_transfer_one(spi, xfer,
	344	is_first_msg, single_xfer);
	345	if (ret < 0) {
	346	dev_err(tsd->dev,
	347	"spi can not start transfer, err %d\n", ret);
	348	goto exit;
	349	}
	350	is_first_msg = false;
	351	ret = wait_for_completion_timeout(&tsd->xfer_completion,
	352	SPI_DMA_TIMEOUT);
	353	if (WARN_ON(ret == 0)) {
	354	dev_err(tsd->dev,
	355	"spi trasfer timeout, err %d\n", ret);
	356	ret = -EIO;
	357	goto exit;
	358	}
	359
	360	if (tsd->tx_status \|\| tsd->rx_status) {
	361	dev_err(tsd->dev, "Error in Transfer\n");
	362	ret = -EIO;
	363	goto exit;
	364	}
	365	msg->actual_length += xfer->len;
	366	if (xfer->cs_change && xfer->delay_usecs) {
	367	tegra_sflash_writel(tsd, tsd->def_command_reg,
	368	SPI_COMMAND);
	369	udelay(xfer->delay_usecs);
	370	}
	371	}
	372	ret = 0;
	373	exit:
	374	tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND);
	375	msg->status = ret;
	376	spi_finalize_current_message(master);
8528547b LD	377	return ret;
	378	}
	379
	380	static irqreturn_t handle_cpu_based_xfer(struct tegra_sflash_data *tsd)
	381	{
	382	struct spi_transfer *t = tsd->curr_xfer;
	383	unsigned long flags;
	384
	385	spin_lock_irqsave(&tsd->lock, flags);
	386	if (tsd->tx_status \|\| tsd->rx_status \|\| (tsd->status_reg & SPI_BSY)) {
	387	dev_err(tsd->dev,
	388	"CpuXfer ERROR bit set 0x%x\n", tsd->status_reg);
	389	dev_err(tsd->dev,
	390	"CpuXfer 0x%08x:0x%08x\n", tsd->command_reg,
	391	tsd->dma_control_reg);
	392	tegra_periph_reset_assert(tsd->clk);
	393	udelay(2);
	394	tegra_periph_reset_deassert(tsd->clk);
	395	complete(&tsd->xfer_completion);
	396	goto exit;
	397	}
	398
	399	if (tsd->cur_direction & DATA_DIR_RX)
	400	tegra_sflash_read_rx_fifo_to_client_rxbuf(tsd, t);
	401
	402	if (tsd->cur_direction & DATA_DIR_TX)
	403	tsd->cur_pos = tsd->cur_tx_pos;
	404	else
	405	tsd->cur_pos = tsd->cur_rx_pos;
	406
	407	if (tsd->cur_pos == t->len) {
	408	complete(&tsd->xfer_completion);
	409	goto exit;
	410	}
	411
	412	tegra_sflash_calculate_curr_xfer_param(tsd->cur_spi, tsd, t);
	413	tegra_sflash_start_cpu_based_transfer(tsd, t);
	414	exit:
	415	spin_unlock_irqrestore(&tsd->lock, flags);
	416	return IRQ_HANDLED;
	417	}
	418
	419	static irqreturn_t tegra_sflash_isr(int irq, void *context_data)
	420	{
	421	struct tegra_sflash_data *tsd = context_data;
	422
	423	tsd->status_reg = tegra_sflash_readl(tsd, SPI_STATUS);
	424	if (tsd->cur_direction & DATA_DIR_TX)
	425	tsd->tx_status = tsd->status_reg & SPI_TX_OVF;
	426
	427	if (tsd->cur_direction & DATA_DIR_RX)
	428	tsd->rx_status = tsd->status_reg & SPI_RX_UNF;
	429	tegra_sflash_clear_status(tsd);
	430
	431	return handle_cpu_based_xfer(tsd);
	432	}
	433
e2546959	434	static void tegra_sflash_parse_dt(struct tegra_sflash_data *tsd)
8528547b	435	{
e2546959	436	struct device_node *np = tsd->dev->of_node;
8528547b	437
e2546959 SW	438	if (of_property_read_u32(np, "spi-max-frequency",
	439	&tsd->spi_max_frequency))
	440	tsd->spi_max_frequency = 25000000; /* 25MHz */
8528547b LD	441	}
8528547b LD	442
fd4a319b	443	static struct of_device_id tegra_sflash_of_match[] = {
8528547b LD	444	{ .compatible = "nvidia,tegra20-sflash", },
	445	{}
	446	};
	447	MODULE_DEVICE_TABLE(of, tegra_sflash_of_match);
	448
fd4a319b	449	static int tegra_sflash_probe(struct platform_device *pdev)
8528547b LD	450	{
	451	struct spi_master *master;
	452	struct tegra_sflash_data *tsd;
	453	struct resource *r;
8528547b LD	454	int ret;
	455	const struct of_device_id *match;
	456
e2546959	457	match = of_match_device(tegra_sflash_of_match, &pdev->dev);
8528547b LD	458	if (!match) {
	459	dev_err(&pdev->dev, "Error: No device match found\n");
	460	return -ENODEV;
	461	}
	462
8528547b LD	463	master = spi_alloc_master(&pdev->dev, sizeof(*tsd));
	464	if (!master) {
	465	dev_err(&pdev->dev, "master allocation failed\n");
	466	return -ENOMEM;
	467	}
	468
	469	/* the spi->mode bits understood by this driver: */
	470	master->mode_bits = SPI_CPOL \| SPI_CPHA;
beb96c2a	471	master->setup = tegra_sflash_setup;
8528547b	472	master->transfer_one_message = tegra_sflash_transfer_one_message;
38315fd4	473	master->auto_runtime_pm = true;
8528547b LD	474	master->num_chipselect = MAX_CHIP_SELECT;
	475	master->bus_num = -1;
	476
24b5a82c	477	platform_set_drvdata(pdev, master);
8528547b LD	478	tsd = spi_master_get_devdata(master);
	479	tsd->master = master;
	480	tsd->dev = &pdev->dev;
	481	spin_lock_init(&tsd->lock);
	482
e2546959 SW	483	tegra_sflash_parse_dt(tsd);
e2546959 SW	484
8528547b	485	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
b0ee5605 TR	486	tsd->base = devm_ioremap_resource(&pdev->dev, r);
	487	if (IS_ERR(tsd->base)) {
	488	ret = PTR_ERR(tsd->base);
8528547b LD	489	goto exit_free_master;
	490	}
	491
	492	tsd->irq = platform_get_irq(pdev, 0);
	493	ret = request_irq(tsd->irq, tegra_sflash_isr, 0,
	494	dev_name(&pdev->dev), tsd);
	495	if (ret < 0) {
	496	dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n",
	497	tsd->irq);
	498	goto exit_free_master;
	499	}
	500
3cb91902	501	tsd->clk = devm_clk_get(&pdev->dev, NULL);
8528547b LD	502	if (IS_ERR(tsd->clk)) {
	503	dev_err(&pdev->dev, "can not get clock\n");
	504	ret = PTR_ERR(tsd->clk);
	505	goto exit_free_irq;
	506	}
	507
8528547b LD	508	init_completion(&tsd->xfer_completion);
	509	pm_runtime_enable(&pdev->dev);
	510	if (!pm_runtime_enabled(&pdev->dev)) {
	511	ret = tegra_sflash_runtime_resume(&pdev->dev);
	512	if (ret)
	513	goto exit_pm_disable;
	514	}
	515
	516	ret = pm_runtime_get_sync(&pdev->dev);
	517	if (ret < 0) {
	518	dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret);
	519	goto exit_pm_disable;
	520	}
	521
	522	/* Reset controller */
	523	tegra_periph_reset_assert(tsd->clk);
	524	udelay(2);
	525	tegra_periph_reset_deassert(tsd->clk);
	526
	527	tsd->def_command_reg = SPI_M_S \| SPI_CS_SW;
	528	tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND);
	529	pm_runtime_put(&pdev->dev);
	530
	531	master->dev.of_node = pdev->dev.of_node;
f12f7318	532	ret = devm_spi_register_master(&pdev->dev, master);
8528547b LD	533	if (ret < 0) {
	534	dev_err(&pdev->dev, "can not register to master err %d\n", ret);
	535	goto exit_pm_disable;
	536	}
	537	return ret;
	538
	539	exit_pm_disable:
	540	pm_runtime_disable(&pdev->dev);
	541	if (!pm_runtime_status_suspended(&pdev->dev))
	542	tegra_sflash_runtime_suspend(&pdev->dev);
	543	exit_free_irq:
	544	free_irq(tsd->irq, tsd);
	545	exit_free_master:
	546	spi_master_put(master);
	547	return ret;
	548	}
	549
fd4a319b	550	static int tegra_sflash_remove(struct platform_device *pdev)
8528547b	551	{
24b5a82c	552	struct spi_master *master = platform_get_drvdata(pdev);
8528547b LD	553	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
	554
	555	free_irq(tsd->irq, tsd);
8528547b LD	556
	557	pm_runtime_disable(&pdev->dev);
	558	if (!pm_runtime_status_suspended(&pdev->dev))
	559	tegra_sflash_runtime_suspend(&pdev->dev);
	560
	561	return 0;
	562	}
	563
	564	#ifdef CONFIG_PM_SLEEP
	565	static int tegra_sflash_suspend(struct device *dev)
	566	{
	567	struct spi_master *master = dev_get_drvdata(dev);
	568
	569	return spi_master_suspend(master);
	570	}
	571
	572	static int tegra_sflash_resume(struct device *dev)
	573	{
	574	struct spi_master *master = dev_get_drvdata(dev);
	575	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
	576	int ret;
	577
	578	ret = pm_runtime_get_sync(dev);
	579	if (ret < 0) {
	580	dev_err(dev, "pm runtime failed, e = %d\n", ret);
	581	return ret;
	582	}
	583	tegra_sflash_writel(tsd, tsd->command_reg, SPI_COMMAND);
	584	pm_runtime_put(dev);
	585
	586	return spi_master_resume(master);
	587	}
	588	#endif
	589
	590	static int tegra_sflash_runtime_suspend(struct device *dev)
	591	{
	592	struct spi_master *master = dev_get_drvdata(dev);
	593	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
	594
	595	/* Flush all write which are in PPSB queue by reading back */
	596	tegra_sflash_readl(tsd, SPI_COMMAND);
	597
	598	clk_disable_unprepare(tsd->clk);
	599	return 0;
	600	}
	601
	602	static int tegra_sflash_runtime_resume(struct device *dev)
	603	{
	604	struct spi_master *master = dev_get_drvdata(dev);
	605	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
	606	int ret;
	607
	608	ret = clk_prepare_enable(tsd->clk);
	609	if (ret < 0) {
	610	dev_err(tsd->dev, "clk_prepare failed: %d\n", ret);
	611	return ret;
	612	}
	613	return 0;
	614	}
	615
	616	static const struct dev_pm_ops slink_pm_ops = {
	617	SET_RUNTIME_PM_OPS(tegra_sflash_runtime_suspend,
	618	tegra_sflash_runtime_resume, NULL)
	619	SET_SYSTEM_SLEEP_PM_OPS(tegra_sflash_suspend, tegra_sflash_resume)
620	};
621	static struct platform_driver tegra_sflash_driver = {
622	.driver = {
623	.name = "spi-tegra-sflash",
624	.owner = THIS_MODULE,
625	.pm = &slink_pm_ops,
e2546959	626	.of_match_table = tegra_sflash_of_match,
8528547b LD	627	},
8528547b LD	628	.probe = tegra_sflash_probe,
fd4a319b	629	.remove = tegra_sflash_remove,
8528547b LD	630	};
	631	module_platform_driver(tegra_sflash_driver);
	632
	633	MODULE_ALIAS("platform:spi-tegra-sflash");
	634	MODULE_DESCRIPTION("NVIDIA Tegra20 Serial Flash Controller Driver");
	635	MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
	636	MODULE_LICENSE("GPL v2");