diff mbox

spi: remove completely broken Tegra driver

Message ID 1348848948-21795-1-git-send-email-swarren@wwwdotorg.org (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Stephen Warren Sept. 28, 2012, 4:15 p.m. UTC
From: Stephen Warren <swarren@nvidia.com>

The current SPI driver has many issues. Examples are:

* Segfaulting on most transfers due to expecting all transfers to have
  both RX and TX buffers.
* Hanging on TX transfers since the whole driver flow is driven by RX
  DMA completion, but the HW is only told to enable RX for RX transfers.
* Use of clk_disable_unprepare() from atomic context.
* Once those and other minor issues are fixed, the driver still doesn't
  actually work.
* The driver also implements a deprecated API to the SPI core.

For this reason, simply remove the driver completely. This has two
advantages:

1) This will remove the last use of Tegra's <mach/dma.h>, which will
   allow that file to be removed, which is required for single zImage
   work.

2) The downstream driver is significaly different from the current
   code. I believe a patch to re-add the downstream driver (with
   appropriate cleanup) will be much simpler to review if it's a new
   file rather than randomly interspered with essentially unrelated
   existing code.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
Mark,

If this can be taken through the SPI tree for 3.7 that'd be great. If
it needs to be deferred to 3.8, we will need to start talking dependencies,
since I'd like to take a patch through the Tegra tree to delete mach/dma.h
in 3.8.
---
 drivers/spi/Kconfig     |    6 -
 drivers/spi/Makefile    |    1 -
 drivers/spi/spi-tegra.c |  702 -----------------------------------------------
 3 files changed, 0 insertions(+), 709 deletions(-)
 delete mode 100644 drivers/spi/spi-tegra.c

Comments

Laxman Dewangan Oct. 1, 2012, 9:41 a.m. UTC | #1
On Friday 28 September 2012 09:45 PM, Stephen Warren wrote:
>
> 2) The downstream driver is significaly different from the current
>     code. I believe a patch to re-add the downstream driver (with
>     appropriate cleanup) will be much simpler to review if it's a new
>     file rather than randomly interspered with essentially unrelated
>     existing code.
>
> Signed-off-by: Stephen Warren<swarren@nvidia.com>
> ---
> Mark,
>
> If this can be taken through the SPI tree for 3.7 that'd be great. If
> it needs to be deferred to 3.8, we will need to start talking dependencies,
> since I'd like to take a patch through the Tegra tree to delete mach/dma.h
> in 3.8.
> ---

Acked by: Laxman Dewangan <ldewangan@nvidia.com>

It will be great if this goes in k3.7 so that we can post the new driver 
on K3.8.
Definitely it will easy to review along with multiple bug fixes which is 
done in driver for interfacing different devices like camera/ touch etc.
Having all these changes on top of existing one will create more than 10 
patches and complicate the review. Also after these many patches, the 
new driver will be look different than the existing one.





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Mark Brown Oct. 1, 2012, 10:20 a.m. UTC | #2
On Mon, Oct 01, 2012 at 03:11:41PM +0530, Laxman Dewangan wrote:

> It will be great if this goes in k3.7 so that we can post the new
> driver on K3.8.

Why would this make any difference to the ability to post a new version?

I do wish stop making up version numbers, it's very irritating.  I
suppose at least people are now including the actual number rather than
the "K32" stuff we used to get :/

> Definitely it will easy to review along with multiple bug fixes
> which is done in driver for interfacing different devices like
> camera/ touch etc.
> Having all these changes on top of existing one will create more
> than 10 patches and complicate the review. Also after these many
> patches, the new driver will be look different than the existing
> one.

You can always just post the removal as the first patch in the series...

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Mark Brown Oct. 1, 2012, 1:02 p.m. UTC | #3
On Fri, Sep 28, 2012 at 10:15:48AM -0600, Stephen Warren wrote:
> From: Stephen Warren <swarren@nvidia.com>
> 
> The current SPI driver has many issues. Examples are:

Applied, thanks.

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diff mbox

Patch

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 63a7943..ecc31a1 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -377,12 +377,6 @@  config SPI_MXS
 	help
 	  SPI driver for Freescale MXS devices.
 
-config SPI_TEGRA
-	tristate "Nvidia Tegra SPI controller"
-	depends on ARCH_TEGRA && (TEGRA_SYSTEM_DMA || TEGRA20_APB_DMA)
-	help
-	  SPI driver for NVidia Tegra SoCs
-
 config SPI_TI_SSP
 	tristate "TI Sequencer Serial Port - SPI Support"
 	depends on MFD_TI_SSP
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 9387056..22fd3a7 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -59,7 +59,6 @@  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-$(CONFIG_SPI_TEGRA)			+= spi-tegra.o
 obj-$(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-tegra.c b/drivers/spi/spi-tegra.c
deleted file mode 100644
index e28445d..0000000
--- a/drivers/spi/spi-tegra.c
+++ /dev/null
@@ -1,702 +0,0 @@ 
-/*
- * Driver for Nvidia TEGRA spi controller.
- *
- * Copyright (C) 2010 Google, Inc.
- *
- * Author:
- *     Erik Gilling <konkers@android.com>
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- */
-
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/err.h>
-#include <linux/platform_device.h>
-#include <linux/io.h>
-#include <linux/dma-mapping.h>
-#include <linux/dmapool.h>
-#include <linux/clk.h>
-#include <linux/interrupt.h>
-#include <linux/delay.h>
-
-#include <linux/spi/spi.h>
-#include <linux/dmaengine.h>
-
-#include <mach/dma.h>
-
-#define SLINK_COMMAND		0x000
-#define   SLINK_BIT_LENGTH(x)		(((x) & 0x1f) << 0)
-#define   SLINK_WORD_SIZE(x)		(((x) & 0x1f) << 5)
-#define   SLINK_BOTH_EN			(1 << 10)
-#define   SLINK_CS_SW			(1 << 11)
-#define   SLINK_CS_VALUE		(1 << 12)
-#define   SLINK_CS_POLARITY		(1 << 13)
-#define   SLINK_IDLE_SDA_DRIVE_LOW	(0 << 16)
-#define   SLINK_IDLE_SDA_DRIVE_HIGH	(1 << 16)
-#define   SLINK_IDLE_SDA_PULL_LOW	(2 << 16)
-#define   SLINK_IDLE_SDA_PULL_HIGH	(3 << 16)
-#define   SLINK_IDLE_SDA_MASK		(3 << 16)
-#define   SLINK_CS_POLARITY1		(1 << 20)
-#define   SLINK_CK_SDA			(1 << 21)
-#define   SLINK_CS_POLARITY2		(1 << 22)
-#define   SLINK_CS_POLARITY3		(1 << 23)
-#define   SLINK_IDLE_SCLK_DRIVE_LOW	(0 << 24)
-#define   SLINK_IDLE_SCLK_DRIVE_HIGH	(1 << 24)
-#define   SLINK_IDLE_SCLK_PULL_LOW	(2 << 24)
-#define   SLINK_IDLE_SCLK_PULL_HIGH	(3 << 24)
-#define   SLINK_IDLE_SCLK_MASK		(3 << 24)
-#define   SLINK_M_S			(1 << 28)
-#define   SLINK_WAIT			(1 << 29)
-#define   SLINK_GO			(1 << 30)
-#define   SLINK_ENB			(1 << 31)
-
-#define SLINK_COMMAND2		0x004
-#define   SLINK_LSBFE			(1 << 0)
-#define   SLINK_SSOE			(1 << 1)
-#define   SLINK_SPIE			(1 << 4)
-#define   SLINK_BIDIROE			(1 << 6)
-#define   SLINK_MODFEN			(1 << 7)
-#define   SLINK_INT_SIZE(x)		(((x) & 0x1f) << 8)
-#define   SLINK_CS_ACTIVE_BETWEEN	(1 << 17)
-#define   SLINK_SS_EN_CS(x)		(((x) & 0x3) << 18)
-#define   SLINK_SS_SETUP(x)		(((x) & 0x3) << 20)
-#define   SLINK_FIFO_REFILLS_0		(0 << 22)
-#define   SLINK_FIFO_REFILLS_1		(1 << 22)
-#define   SLINK_FIFO_REFILLS_2		(2 << 22)
-#define   SLINK_FIFO_REFILLS_3		(3 << 22)
-#define   SLINK_FIFO_REFILLS_MASK	(3 << 22)
-#define   SLINK_WAIT_PACK_INT(x)	(((x) & 0x7) << 26)
-#define   SLINK_SPC0			(1 << 29)
-#define   SLINK_TXEN			(1 << 30)
-#define   SLINK_RXEN			(1 << 31)
-
-#define SLINK_STATUS		0x008
-#define   SLINK_COUNT(val)		(((val) >> 0) & 0x1f)
-#define   SLINK_WORD(val)		(((val) >> 5) & 0x1f)
-#define   SLINK_BLK_CNT(val)		(((val) >> 0) & 0xffff)
-#define   SLINK_MODF			(1 << 16)
-#define   SLINK_RX_UNF			(1 << 18)
-#define   SLINK_TX_OVF			(1 << 19)
-#define   SLINK_TX_FULL			(1 << 20)
-#define   SLINK_TX_EMPTY		(1 << 21)
-#define   SLINK_RX_FULL			(1 << 22)
-#define   SLINK_RX_EMPTY		(1 << 23)
-#define   SLINK_TX_UNF			(1 << 24)
-#define   SLINK_RX_OVF			(1 << 25)
-#define   SLINK_TX_FLUSH		(1 << 26)
-#define   SLINK_RX_FLUSH		(1 << 27)
-#define   SLINK_SCLK			(1 << 28)
-#define   SLINK_ERR			(1 << 29)
-#define   SLINK_RDY			(1 << 30)
-#define   SLINK_BSY			(1 << 31)
-
-#define SLINK_MAS_DATA		0x010
-#define SLINK_SLAVE_DATA	0x014
-
-#define SLINK_DMA_CTL		0x018
-#define   SLINK_DMA_BLOCK_SIZE(x)	(((x) & 0xffff) << 0)
-#define   SLINK_TX_TRIG_1		(0 << 16)
-#define   SLINK_TX_TRIG_4		(1 << 16)
-#define   SLINK_TX_TRIG_8		(2 << 16)
-#define   SLINK_TX_TRIG_16		(3 << 16)
-#define   SLINK_TX_TRIG_MASK		(3 << 16)
-#define   SLINK_RX_TRIG_1		(0 << 18)
-#define   SLINK_RX_TRIG_4		(1 << 18)
-#define   SLINK_RX_TRIG_8		(2 << 18)
-#define   SLINK_RX_TRIG_16		(3 << 18)
-#define   SLINK_RX_TRIG_MASK		(3 << 18)
-#define   SLINK_PACKED			(1 << 20)
-#define   SLINK_PACK_SIZE_4		(0 << 21)
-#define   SLINK_PACK_SIZE_8		(1 << 21)
-#define   SLINK_PACK_SIZE_16		(2 << 21)
-#define   SLINK_PACK_SIZE_32		(3 << 21)
-#define   SLINK_PACK_SIZE_MASK		(3 << 21)
-#define   SLINK_IE_TXC			(1 << 26)
-#define   SLINK_IE_RXC			(1 << 27)
-#define   SLINK_DMA_EN			(1 << 31)
-
-#define SLINK_STATUS2		0x01c
-#define   SLINK_TX_FIFO_EMPTY_COUNT(val)	(((val) & 0x3f) >> 0)
-#define   SLINK_RX_FIFO_FULL_COUNT(val)		(((val) & 0x3f) >> 16)
-
-#define SLINK_TX_FIFO		0x100
-#define SLINK_RX_FIFO		0x180
-
-static const unsigned long spi_tegra_req_sels[] = {
-	TEGRA_DMA_REQ_SEL_SL2B1,
-	TEGRA_DMA_REQ_SEL_SL2B2,
-	TEGRA_DMA_REQ_SEL_SL2B3,
-	TEGRA_DMA_REQ_SEL_SL2B4,
-};
-
-#define BB_LEN			32
-
-struct spi_tegra_data {
-	struct spi_master	*master;
-	struct platform_device	*pdev;
-	spinlock_t		lock;
-
-	struct clk		*clk;
-	void __iomem		*base;
-	unsigned long		phys;
-
-	u32			cur_speed;
-
-	struct list_head	queue;
-	struct spi_transfer	*cur;
-	unsigned		cur_pos;
-	unsigned		cur_len;
-	unsigned		cur_bytes_per_word;
-
-	/* The tegra spi controller has a bug which causes the first word
-	 * in PIO transactions to be garbage.  Since packed DMA transactions
-	 * require transfers to be 4 byte aligned we need a bounce buffer
-	 * for the generic case.
-	 */
-	int			dma_req_len;
-#if defined(CONFIG_TEGRA_SYSTEM_DMA)
-	struct tegra_dma_req	rx_dma_req;
-	struct tegra_dma_channel *rx_dma;
-#else
-	struct dma_chan		*rx_dma;
-	struct dma_slave_config	sconfig;
-	struct dma_async_tx_descriptor	*rx_dma_desc;
-	dma_cookie_t		rx_cookie;
-#endif
-	u32			*rx_bb;
-	dma_addr_t		rx_bb_phys;
-};
-
-#if !defined(CONFIG_TEGRA_SYSTEM_DMA)
-static void tegra_spi_rx_dma_complete(void *args);
-#endif
-
-static inline unsigned long spi_tegra_readl(struct spi_tegra_data *tspi,
-					    unsigned long reg)
-{
-	return readl(tspi->base + reg);
-}
-
-static inline void spi_tegra_writel(struct spi_tegra_data *tspi,
-				    unsigned long val,
-				    unsigned long reg)
-{
-	writel(val, tspi->base + reg);
-}
-
-static void spi_tegra_go(struct spi_tegra_data *tspi)
-{
-	unsigned long val;
-
-	wmb();
-
-	val = spi_tegra_readl(tspi, SLINK_DMA_CTL);
-	val &= ~SLINK_DMA_BLOCK_SIZE(~0) & ~SLINK_DMA_EN;
-	val |= SLINK_DMA_BLOCK_SIZE(tspi->dma_req_len / 4 - 1);
-	spi_tegra_writel(tspi, val, SLINK_DMA_CTL);
-#if defined(CONFIG_TEGRA_SYSTEM_DMA)
-	tspi->rx_dma_req.size = tspi->dma_req_len;
-	tegra_dma_enqueue_req(tspi->rx_dma, &tspi->rx_dma_req);
-#else
-	tspi->rx_dma_desc = dmaengine_prep_slave_single(tspi->rx_dma,
-				tspi->rx_bb_phys, tspi->dma_req_len,
-				DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
-	if (!tspi->rx_dma_desc) {
-		dev_err(&tspi->pdev->dev, "dmaengine slave prep failed\n");
-		return;
-	}
-	tspi->rx_dma_desc->callback = tegra_spi_rx_dma_complete;
-	tspi->rx_dma_desc->callback_param = tspi;
-	tspi->rx_cookie = dmaengine_submit(tspi->rx_dma_desc);
-	dma_async_issue_pending(tspi->rx_dma);
-#endif
-
-	val |= SLINK_DMA_EN;
-	spi_tegra_writel(tspi, val, SLINK_DMA_CTL);
-}
-
-static unsigned spi_tegra_fill_tx_fifo(struct spi_tegra_data *tspi,
-				  struct spi_transfer *t)
-{
-	unsigned len = min(t->len - tspi->cur_pos, BB_LEN *
-			   tspi->cur_bytes_per_word);
-	u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_pos;
-	int i, j;
-	unsigned long val;
-
-	val = spi_tegra_readl(tspi, SLINK_COMMAND);
-	val &= ~SLINK_WORD_SIZE(~0);
-	val |= SLINK_WORD_SIZE(len / tspi->cur_bytes_per_word - 1);
-	spi_tegra_writel(tspi, val, SLINK_COMMAND);
-
-	for (i = 0; i < len; i += tspi->cur_bytes_per_word) {
-		val = 0;
-		for (j = 0; j < tspi->cur_bytes_per_word; j++)
-			val |= tx_buf[i + j] << j * 8;
-
-		spi_tegra_writel(tspi, val, SLINK_TX_FIFO);
-	}
-
-	tspi->dma_req_len = len / tspi->cur_bytes_per_word * 4;
-
-	return len;
-}
-
-static unsigned spi_tegra_drain_rx_fifo(struct spi_tegra_data *tspi,
-				  struct spi_transfer *t)
-{
-	unsigned len = tspi->cur_len;
-	u8 *rx_buf = (u8 *)t->rx_buf + tspi->cur_pos;
-	int i, j;
-	unsigned long val;
-
-	for (i = 0; i < len; i += tspi->cur_bytes_per_word) {
-		val = tspi->rx_bb[i / tspi->cur_bytes_per_word];
-		for (j = 0; j < tspi->cur_bytes_per_word; j++)
-			rx_buf[i + j] = (val >> (j * 8)) & 0xff;
-	}
-
-	return len;
-}
-
-static void spi_tegra_start_transfer(struct spi_device *spi,
-				    struct spi_transfer *t)
-{
-	struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master);
-	u32 speed;
-	u8 bits_per_word;
-	unsigned long val;
-
-	speed = t->speed_hz ? t->speed_hz : spi->max_speed_hz;
-	bits_per_word = t->bits_per_word ? t->bits_per_word  :
-		spi->bits_per_word;
-
-	tspi->cur_bytes_per_word = (bits_per_word - 1) / 8 + 1;
-
-	if (speed != tspi->cur_speed)
-		clk_set_rate(tspi->clk, speed);
-
-	if (tspi->cur_speed == 0)
-		clk_prepare_enable(tspi->clk);
-
-	tspi->cur_speed = speed;
-
-	val = spi_tegra_readl(tspi, SLINK_COMMAND2);
-	val &= ~SLINK_SS_EN_CS(~0) | SLINK_RXEN | SLINK_TXEN;
-	if (t->rx_buf)
-		val |= SLINK_RXEN;
-	if (t->tx_buf)
-		val |= SLINK_TXEN;
-	val |= SLINK_SS_EN_CS(spi->chip_select);
-	val |= SLINK_SPIE;
-	spi_tegra_writel(tspi, val, SLINK_COMMAND2);
-
-	val = spi_tegra_readl(tspi, SLINK_COMMAND);
-	val &= ~SLINK_BIT_LENGTH(~0);
-	val |= SLINK_BIT_LENGTH(bits_per_word - 1);
-
-	/* FIXME: should probably control CS manually so that we can be sure
-	 * it does not go low between transfer and to support delay_usecs
-	 * correctly.
-	 */
-	val &= ~SLINK_IDLE_SCLK_MASK & ~SLINK_CK_SDA & ~SLINK_CS_SW;
-
-	if (spi->mode & SPI_CPHA)
-		val |= SLINK_CK_SDA;
-
-	if (spi->mode & SPI_CPOL)
-		val |= SLINK_IDLE_SCLK_DRIVE_HIGH;
-	else
-		val |= SLINK_IDLE_SCLK_DRIVE_LOW;
-
-	val |= SLINK_M_S;
-
-	spi_tegra_writel(tspi, val, SLINK_COMMAND);
-
-	spi_tegra_writel(tspi, SLINK_RX_FLUSH | SLINK_TX_FLUSH, SLINK_STATUS);
-
-	tspi->cur = t;
-	tspi->cur_pos = 0;
-	tspi->cur_len = spi_tegra_fill_tx_fifo(tspi, t);
-
-	spi_tegra_go(tspi);
-}
-
-static void spi_tegra_start_message(struct spi_device *spi,
-				    struct spi_message *m)
-{
-	struct spi_transfer *t;
-
-	m->actual_length = 0;
-	m->status = 0;
-
-	t = list_first_entry(&m->transfers, struct spi_transfer, transfer_list);
-	spi_tegra_start_transfer(spi, t);
-}
-
-static void handle_spi_rx_dma_complete(struct spi_tegra_data *tspi)
-{
-	unsigned long flags;
-	struct spi_message *m;
-	struct spi_device *spi;
-	int timeout = 0;
-	unsigned long val;
-
-	/* the SPI controller may come back with both the BSY and RDY bits
-	 * set.  In this case we need to wait for the BSY bit to clear so
-	 * that we are sure the DMA is finished.  1000 reads was empirically
-	 * determined to be long enough.
-	 */
-	while (timeout++ < 1000) {
-		if (!(spi_tegra_readl(tspi, SLINK_STATUS) & SLINK_BSY))
-			break;
-	}
-
-	spin_lock_irqsave(&tspi->lock, flags);
-
-	val = spi_tegra_readl(tspi, SLINK_STATUS);
-	val |= SLINK_RDY;
-	spi_tegra_writel(tspi, val, SLINK_STATUS);
-
-	m = list_first_entry(&tspi->queue, struct spi_message, queue);
-
-	if (timeout >= 1000)
-		m->status = -EIO;
-
-	spi = m->state;
-
-	tspi->cur_pos += spi_tegra_drain_rx_fifo(tspi, tspi->cur);
-	m->actual_length += tspi->cur_pos;
-
-	if (tspi->cur_pos < tspi->cur->len) {
-		tspi->cur_len = spi_tegra_fill_tx_fifo(tspi, tspi->cur);
-		spi_tegra_go(tspi);
-	} else if (!list_is_last(&tspi->cur->transfer_list,
-				 &m->transfers)) {
-		tspi->cur =  list_first_entry(&tspi->cur->transfer_list,
-					      struct spi_transfer,
-					      transfer_list);
-		spi_tegra_start_transfer(spi, tspi->cur);
-	} else {
-		list_del(&m->queue);
-
-		m->complete(m->context);
-
-		if (!list_empty(&tspi->queue)) {
-			m = list_first_entry(&tspi->queue, struct spi_message,
-					     queue);
-			spi = m->state;
-			spi_tegra_start_message(spi, m);
-		} else {
-			clk_disable_unprepare(tspi->clk);
-			tspi->cur_speed = 0;
-		}
-	}
-
-	spin_unlock_irqrestore(&tspi->lock, flags);
-}
-#if defined(CONFIG_TEGRA_SYSTEM_DMA)
-static void tegra_spi_rx_dma_complete(struct tegra_dma_req *req)
-{
-	struct spi_tegra_data *tspi = req->dev;
-	handle_spi_rx_dma_complete(tspi);
-}
-#else
-static void tegra_spi_rx_dma_complete(void *args)
-{
-	struct spi_tegra_data *tspi = args;
-	handle_spi_rx_dma_complete(tspi);
-}
-#endif
-
-static int spi_tegra_setup(struct spi_device *spi)
-{
-	struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master);
-	unsigned long cs_bit;
-	unsigned long val;
-	unsigned long flags;
-
-	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);
-
-
-	switch (spi->chip_select) {
-	case 0:
-		cs_bit = SLINK_CS_POLARITY;
-		break;
-
-	case 1:
-		cs_bit = SLINK_CS_POLARITY1;
-		break;
-
-	case 2:
-		cs_bit = SLINK_CS_POLARITY2;
-		break;
-
-	case 4:
-		cs_bit = SLINK_CS_POLARITY3;
-		break;
-
-	default:
-		return -EINVAL;
-	}
-
-	spin_lock_irqsave(&tspi->lock, flags);
-
-	val = spi_tegra_readl(tspi, SLINK_COMMAND);
-	if (spi->mode & SPI_CS_HIGH)
-		val |= cs_bit;
-	else
-		val &= ~cs_bit;
-	spi_tegra_writel(tspi, val, SLINK_COMMAND);
-
-	spin_unlock_irqrestore(&tspi->lock, flags);
-
-	return 0;
-}
-
-static int spi_tegra_transfer(struct spi_device *spi, struct spi_message *m)
-{
-	struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master);
-	struct spi_transfer *t;
-	unsigned long flags;
-	int was_empty;
-
-	if (list_empty(&m->transfers) || !m->complete)
-		return -EINVAL;
-
-	list_for_each_entry(t, &m->transfers, transfer_list) {
-		if (t->bits_per_word < 0 || t->bits_per_word > 32)
-			return -EINVAL;
-
-		if (t->len == 0)
-			return -EINVAL;
-
-		if (!t->rx_buf && !t->tx_buf)
-			return -EINVAL;
-	}
-
-	m->state = spi;
-
-	spin_lock_irqsave(&tspi->lock, flags);
-	was_empty = list_empty(&tspi->queue);
-	list_add_tail(&m->queue, &tspi->queue);
-
-	if (was_empty)
-		spi_tegra_start_message(spi, m);
-
-	spin_unlock_irqrestore(&tspi->lock, flags);
-
-	return 0;
-}
-
-static int __devinit spi_tegra_probe(struct platform_device *pdev)
-{
-	struct spi_master	*master;
-	struct spi_tegra_data	*tspi;
-	struct resource		*r;
-	int ret;
-#if !defined(CONFIG_TEGRA_SYSTEM_DMA)
-	dma_cap_mask_t mask;
-#endif
-
-	master = spi_alloc_master(&pdev->dev, sizeof *tspi);
-	if (master == NULL) {
-		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 | SPI_CS_HIGH;
-
-	master->bus_num = pdev->id;
-
-	master->setup = spi_tegra_setup;
-	master->transfer = spi_tegra_transfer;
-	master->num_chipselect = 4;
-
-	dev_set_drvdata(&pdev->dev, master);
-	tspi = spi_master_get_devdata(master);
-	tspi->master = master;
-	tspi->pdev = pdev;
-	spin_lock_init(&tspi->lock);
-
-	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (r == NULL) {
-		ret = -ENODEV;
-		goto err0;
-	}
-
-	if (!request_mem_region(r->start, resource_size(r),
-				dev_name(&pdev->dev))) {
-		ret = -EBUSY;
-		goto err0;
-	}
-
-	tspi->phys = r->start;
-	tspi->base = ioremap(r->start, resource_size(r));
-	if (!tspi->base) {
-		dev_err(&pdev->dev, "can't ioremap iomem\n");
-		ret = -ENOMEM;
-		goto err1;
-	}
-
-	tspi->clk = clk_get(&pdev->dev, NULL);
-	if (IS_ERR(tspi->clk)) {
-		dev_err(&pdev->dev, "can not get clock\n");
-		ret = PTR_ERR(tspi->clk);
-		goto err2;
-	}
-
-	INIT_LIST_HEAD(&tspi->queue);
-
-#if defined(CONFIG_TEGRA_SYSTEM_DMA)
-	tspi->rx_dma = tegra_dma_allocate_channel(TEGRA_DMA_MODE_ONESHOT);
-	if (!tspi->rx_dma) {
-		dev_err(&pdev->dev, "can not allocate rx dma channel\n");
-		ret = -ENODEV;
-		goto err3;
-	}
-#else
-	dma_cap_zero(mask);
-	dma_cap_set(DMA_SLAVE, mask);
-	tspi->rx_dma = dma_request_channel(mask, NULL, NULL);
-	if (!tspi->rx_dma) {
-		dev_err(&pdev->dev, "can not allocate rx dma channel\n");
-		ret = -ENODEV;
-		goto err3;
-	}
-
-#endif
-
-	tspi->rx_bb = dma_alloc_coherent(&pdev->dev, sizeof(u32) * BB_LEN,
-					 &tspi->rx_bb_phys, GFP_KERNEL);
-	if (!tspi->rx_bb) {
-		dev_err(&pdev->dev, "can not allocate rx bounce buffer\n");
-		ret = -ENOMEM;
-		goto err4;
-	}
-
-#if defined(CONFIG_TEGRA_SYSTEM_DMA)
-	tspi->rx_dma_req.complete = tegra_spi_rx_dma_complete;
-	tspi->rx_dma_req.to_memory = 1;
-	tspi->rx_dma_req.dest_addr = tspi->rx_bb_phys;
-	tspi->rx_dma_req.dest_bus_width = 32;
-	tspi->rx_dma_req.source_addr = tspi->phys + SLINK_RX_FIFO;
-	tspi->rx_dma_req.source_bus_width = 32;
-	tspi->rx_dma_req.source_wrap = 4;
-	tspi->rx_dma_req.req_sel = spi_tegra_req_sels[pdev->id];
-	tspi->rx_dma_req.dev = tspi;
-#else
-	/* Dmaengine Dma slave config */
-	tspi->sconfig.src_addr = tspi->phys + SLINK_RX_FIFO;
-	tspi->sconfig.dst_addr = tspi->phys + SLINK_RX_FIFO;
-	tspi->sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-	tspi->sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-	tspi->sconfig.slave_id = spi_tegra_req_sels[pdev->id];
-	tspi->sconfig.src_maxburst = 1;
-	tspi->sconfig.dst_maxburst = 1;
-	ret = dmaengine_device_control(tspi->rx_dma,
-			DMA_SLAVE_CONFIG, (unsigned long) &tspi->sconfig);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "can not do slave configure for dma %d\n",
-			ret);
-		goto err4;
-	}
-#endif
-
-	master->dev.of_node = pdev->dev.of_node;
-	ret = spi_register_master(master);
-
-	if (ret < 0)
-		goto err5;
-
-	return ret;
-
-err5:
-	dma_free_coherent(&pdev->dev, sizeof(u32) * BB_LEN,
-			  tspi->rx_bb, tspi->rx_bb_phys);
-err4:
-#if defined(CONFIG_TEGRA_SYSTEM_DMA)
-	tegra_dma_free_channel(tspi->rx_dma);
-#else
-	dma_release_channel(tspi->rx_dma);
-#endif
-err3:
-	clk_put(tspi->clk);
-err2:
-	iounmap(tspi->base);
-err1:
-	release_mem_region(r->start, resource_size(r));
-err0:
-	spi_master_put(master);
-	return ret;
-}
-
-static int __devexit spi_tegra_remove(struct platform_device *pdev)
-{
-	struct spi_master	*master;
-	struct spi_tegra_data	*tspi;
-	struct resource		*r;
-
-	master = spi_master_get(dev_get_drvdata(&pdev->dev));
-	tspi = spi_master_get_devdata(master);
-
-	spi_unregister_master(master);
-#if defined(CONFIG_TEGRA_SYSTEM_DMA)
-	tegra_dma_free_channel(tspi->rx_dma);
-#else
-	dma_release_channel(tspi->rx_dma);
-#endif
-
-	dma_free_coherent(&pdev->dev, sizeof(u32) * BB_LEN,
-			  tspi->rx_bb, tspi->rx_bb_phys);
-
-	clk_put(tspi->clk);
-	iounmap(tspi->base);
-
-	spi_master_put(master);
-
-	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	release_mem_region(r->start, resource_size(r));
-
-	return 0;
-}
-
-MODULE_ALIAS("platform:spi_tegra");
-
-#ifdef CONFIG_OF
-static struct of_device_id spi_tegra_of_match_table[] __devinitdata = {
-	{ .compatible = "nvidia,tegra20-spi", },
-	{}
-};
-MODULE_DEVICE_TABLE(of, spi_tegra_of_match_table);
-#else /* CONFIG_OF */
-#define spi_tegra_of_match_table NULL
-#endif /* CONFIG_OF */
-
-static struct platform_driver spi_tegra_driver = {
-	.driver = {
-		.name =		"spi_tegra",
-		.owner =	THIS_MODULE,
-		.of_match_table = spi_tegra_of_match_table,
-	},
-	.probe =	spi_tegra_probe,
-	.remove =	__devexit_p(spi_tegra_remove),
-};
-module_platform_driver(spi_tegra_driver);
-
-MODULE_LICENSE("GPL");