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path: root/drivers/spi/spi-tegra20-slink.c
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-rw-r--r--drivers/spi/spi-tegra20-slink.c1232
1 files changed, 1232 insertions, 0 deletions
diff --git a/drivers/spi/spi-tegra20-slink.c b/drivers/spi/spi-tegra20-slink.c
new file mode 100644
index 000000000..24cab56ec
--- /dev/null
+++ b/drivers/spi/spi-tegra20-slink.c
@@ -0,0 +1,1232 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SPI driver for Nvidia's Tegra20/Tegra30 SLINK Controller.
+ *
+ * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
+ */
+
+#include <linux/clk.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/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_opp.h>
+#include <linux/pm_runtime.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/reset.h>
+#include <linux/spi/spi.h>
+
+#include <soc/tegra/common.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_MODES (SLINK_IDLE_SCLK_MASK | SLINK_CK_SDA)
+
+#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_FIFO_ERROR (SLINK_TX_OVF | SLINK_RX_UNF | \
+ SLINK_TX_UNF | SLINK_RX_OVF)
+
+#define SLINK_FIFO_EMPTY (SLINK_TX_EMPTY | SLINK_RX_EMPTY)
+
+#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) & 0x3f0000) >> 16)
+#define SLINK_SS_HOLD_TIME(val) (((val) & 0xF) << 6)
+
+#define SLINK_TX_FIFO 0x100
+#define SLINK_RX_FIFO 0x180
+
+#define DATA_DIR_TX (1 << 0)
+#define DATA_DIR_RX (1 << 1)
+
+#define SLINK_DMA_TIMEOUT (msecs_to_jiffies(1000))
+
+#define DEFAULT_SPI_DMA_BUF_LEN (16*1024)
+#define TX_FIFO_EMPTY_COUNT_MAX SLINK_TX_FIFO_EMPTY_COUNT(0x20)
+#define RX_FIFO_FULL_COUNT_ZERO SLINK_RX_FIFO_FULL_COUNT(0)
+
+#define SLINK_STATUS2_RESET \
+ (TX_FIFO_EMPTY_COUNT_MAX | RX_FIFO_FULL_COUNT_ZERO << 16)
+
+#define MAX_CHIP_SELECT 4
+#define SLINK_FIFO_DEPTH 32
+
+struct tegra_slink_chip_data {
+ bool cs_hold_time;
+};
+
+struct tegra_slink_data {
+ struct device *dev;
+ struct spi_master *master;
+ const struct tegra_slink_chip_data *chip_data;
+ spinlock_t lock;
+
+ struct clk *clk;
+ struct reset_control *rst;
+ void __iomem *base;
+ phys_addr_t phys;
+ unsigned irq;
+ 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;
+ u32 packed_size;
+
+ u32 command_reg;
+ u32 command2_reg;
+ u32 dma_control_reg;
+ u32 def_command_reg;
+ u32 def_command2_reg;
+
+ 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 inline u32 tegra_slink_readl(struct tegra_slink_data *tspi,
+ unsigned long reg)
+{
+ return readl(tspi->base + reg);
+}
+
+static inline void tegra_slink_writel(struct tegra_slink_data *tspi,
+ u32 val, unsigned long reg)
+{
+ writel(val, tspi->base + reg);
+
+ /* Read back register to make sure that register writes completed */
+ if (reg != SLINK_TX_FIFO)
+ readl(tspi->base + SLINK_MAS_DATA);
+}
+
+static void tegra_slink_clear_status(struct tegra_slink_data *tspi)
+{
+ u32 val_write;
+
+ tegra_slink_readl(tspi, SLINK_STATUS);
+
+ /* Write 1 to clear status register */
+ val_write = SLINK_RDY | SLINK_FIFO_ERROR;
+ tegra_slink_writel(tspi, val_write, SLINK_STATUS);
+}
+
+static u32 tegra_slink_get_packed_size(struct tegra_slink_data *tspi,
+ struct spi_transfer *t)
+{
+ switch (tspi->bytes_per_word) {
+ case 0:
+ return SLINK_PACK_SIZE_4;
+ case 1:
+ return SLINK_PACK_SIZE_8;
+ case 2:
+ return SLINK_PACK_SIZE_16;
+ case 4:
+ return SLINK_PACK_SIZE_32;
+ default:
+ return 0;
+ }
+}
+
+static unsigned tegra_slink_calculate_curr_xfer_param(
+ struct spi_device *spi, struct tegra_slink_data *tspi,
+ struct spi_transfer *t)
+{
+ unsigned remain_len = t->len - tspi->cur_pos;
+ unsigned max_word;
+ unsigned bits_per_word;
+ unsigned max_len;
+ unsigned total_fifo_words;
+
+ bits_per_word = t->bits_per_word;
+ tspi->bytes_per_word = DIV_ROUND_UP(bits_per_word, 8);
+
+ if (bits_per_word == 8 || bits_per_word == 16) {
+ tspi->is_packed = true;
+ tspi->words_per_32bit = 32/bits_per_word;
+ } else {
+ tspi->is_packed = false;
+ tspi->words_per_32bit = 1;
+ }
+ tspi->packed_size = tegra_slink_get_packed_size(tspi, t);
+
+ 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/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_slink_fill_tx_fifo_from_client_txbuf(
+ struct tegra_slink_data *tspi, struct spi_transfer *t)
+{
+ unsigned nbytes;
+ unsigned tx_empty_count;
+ u32 fifo_status;
+ unsigned max_n_32bit;
+ unsigned i, count;
+ unsigned int written_words;
+ unsigned fifo_words_left;
+ u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_tx_pos;
+
+ fifo_status = tegra_slink_readl(tspi, SLINK_STATUS2);
+ tx_empty_count = SLINK_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++) {
+ u32 x = 0;
+ for (i = 0; (i < 4) && nbytes; i++, nbytes--)
+ x |= (u32)(*tx_buf++) << (i * 8);
+ tegra_slink_writel(tspi, x, SLINK_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++) {
+ u32 x = 0;
+ for (i = 0; nbytes && (i < tspi->bytes_per_word);
+ i++, nbytes--)
+ x |= (u32)(*tx_buf++) << (i * 8);
+ tegra_slink_writel(tspi, x, SLINK_TX_FIFO);
+ }
+ }
+ tspi->cur_tx_pos += written_words * tspi->bytes_per_word;
+ return written_words;
+}
+
+static unsigned int tegra_slink_read_rx_fifo_to_client_rxbuf(
+ struct tegra_slink_data *tspi, struct spi_transfer *t)
+{
+ unsigned rx_full_count;
+ u32 fifo_status;
+ unsigned i, count;
+ unsigned int read_words = 0;
+ unsigned len;
+ u8 *rx_buf = (u8 *)t->rx_buf + tspi->cur_rx_pos;
+
+ fifo_status = tegra_slink_readl(tspi, SLINK_STATUS2);
+ rx_full_count = SLINK_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++) {
+ u32 x = tegra_slink_readl(tspi, SLINK_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 {
+ for (count = 0; count < rx_full_count; count++) {
+ u32 x = tegra_slink_readl(tspi, SLINK_RX_FIFO);
+ 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_slink_copy_client_txbuf_to_spi_txbuf(
+ struct tegra_slink_data *tspi, struct spi_transfer *t)
+{
+ /* 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) {
+ unsigned 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;
+
+ for (count = 0; count < tspi->curr_dma_words; count++) {
+ u32 x = 0;
+ for (i = 0; consume && (i < tspi->bytes_per_word);
+ i++, consume--)
+ x |= (u32)(*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_slink_copy_spi_rxbuf_to_client_rxbuf(
+ struct tegra_slink_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;
+ u32 rx_mask = ((u32)1 << t->bits_per_word) - 1;
+
+ for (count = 0; count < tspi->curr_dma_words; count++) {
+ u32 x = tspi->rx_dma_buf[count] & 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_slink_dma_complete(void *args)
+{
+ struct completion *dma_complete = args;
+
+ complete(dma_complete);
+}
+
+static int tegra_slink_start_tx_dma(struct tegra_slink_data *tspi, int len)
+{
+ reinit_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_slink_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_slink_start_rx_dma(struct tegra_slink_data *tspi, int len)
+{
+ reinit_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_slink_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_slink_start_dma_based_transfer(
+ struct tegra_slink_data *tspi, struct spi_transfer *t)
+{
+ u32 val;
+ unsigned int len;
+ int ret = 0;
+ u32 status;
+
+ /* Make sure that Rx and Tx fifo are empty */
+ status = tegra_slink_readl(tspi, SLINK_STATUS);
+ if ((status & SLINK_FIFO_EMPTY) != SLINK_FIFO_EMPTY) {
+ dev_err(tspi->dev, "Rx/Tx fifo are not empty status 0x%08x\n",
+ (unsigned)status);
+ return -EIO;
+ }
+
+ val = SLINK_DMA_BLOCK_SIZE(tspi->curr_dma_words - 1);
+ val |= tspi->packed_size;
+ 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 |= SLINK_TX_TRIG_1 | SLINK_RX_TRIG_1;
+ else if (((len) >> 4) & 0x1)
+ val |= SLINK_TX_TRIG_4 | SLINK_RX_TRIG_4;
+ else
+ val |= SLINK_TX_TRIG_8 | SLINK_RX_TRIG_8;
+
+ if (tspi->cur_direction & DATA_DIR_TX)
+ val |= SLINK_IE_TXC;
+
+ if (tspi->cur_direction & DATA_DIR_RX)
+ val |= SLINK_IE_RXC;
+
+ tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+ tspi->dma_control_reg = val;
+
+ if (tspi->cur_direction & DATA_DIR_TX) {
+ tegra_slink_copy_client_txbuf_to_spi_txbuf(tspi, t);
+ wmb();
+ ret = tegra_slink_start_tx_dma(tspi, len);
+ if (ret < 0) {
+ dev_err(tspi->dev,
+ "Starting tx dma failed, err %d\n", ret);
+ return ret;
+ }
+
+ /* Wait for tx fifo to be fill before starting slink */
+ status = tegra_slink_readl(tspi, SLINK_STATUS);
+ while (!(status & SLINK_TX_FULL))
+ status = tegra_slink_readl(tspi, SLINK_STATUS);
+ }
+
+ 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_slink_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;
+ if (tspi->is_packed) {
+ val |= SLINK_PACKED;
+ tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+ /* HW need small delay after settign Packed mode */
+ udelay(1);
+ }
+ tspi->dma_control_reg = val;
+
+ val |= SLINK_DMA_EN;
+ tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+ return ret;
+}
+
+static int tegra_slink_start_cpu_based_transfer(
+ struct tegra_slink_data *tspi, struct spi_transfer *t)
+{
+ u32 val;
+ unsigned cur_words;
+
+ val = tspi->packed_size;
+ if (tspi->cur_direction & DATA_DIR_TX)
+ val |= SLINK_IE_TXC;
+
+ if (tspi->cur_direction & DATA_DIR_RX)
+ val |= SLINK_IE_RXC;
+
+ tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+ tspi->dma_control_reg = val;
+
+ if (tspi->cur_direction & DATA_DIR_TX)
+ cur_words = tegra_slink_fill_tx_fifo_from_client_txbuf(tspi, t);
+ else
+ cur_words = tspi->curr_dma_words;
+ val |= SLINK_DMA_BLOCK_SIZE(cur_words - 1);
+ tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+ tspi->dma_control_reg = val;
+
+ tspi->is_curr_dma_xfer = false;
+ if (tspi->is_packed) {
+ val |= SLINK_PACKED;
+ tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+ udelay(1);
+ wmb();
+ }
+ tspi->dma_control_reg = val;
+ val |= SLINK_DMA_EN;
+ tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+ return 0;
+}
+
+static int tegra_slink_init_dma_param(struct tegra_slink_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_chan = dma_request_chan(tspi->dev, dma_to_memory ? "rx" : "tx");
+ if (IS_ERR(dma_chan))
+ return dev_err_probe(tspi->dev, PTR_ERR(dma_chan),
+ "Dma channel is not available\n");
+
+ 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;
+ }
+
+ if (dma_to_memory) {
+ dma_sconfig.src_addr = tspi->phys + SLINK_RX_FIFO;
+ dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ dma_sconfig.src_maxburst = 0;
+ } else {
+ dma_sconfig.dst_addr = tspi->phys + SLINK_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_slink_deinit_dma_param(struct tegra_slink_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_slink_start_transfer_one(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct tegra_slink_data *tspi = spi_master_get_devdata(spi->master);
+ u32 speed;
+ u8 bits_per_word;
+ unsigned total_fifo_words;
+ int ret;
+ u32 command;
+ u32 command2;
+
+ bits_per_word = t->bits_per_word;
+ speed = t->speed_hz;
+ if (speed != tspi->cur_speed) {
+ dev_pm_opp_set_rate(tspi->dev, speed * 4);
+ 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_slink_calculate_curr_xfer_param(spi, tspi, t);
+
+ command = tspi->command_reg;
+ command &= ~SLINK_BIT_LENGTH(~0);
+ command |= SLINK_BIT_LENGTH(bits_per_word - 1);
+
+ command2 = tspi->command2_reg;
+ command2 &= ~(SLINK_RXEN | SLINK_TXEN);
+
+ tspi->cur_direction = 0;
+ if (t->rx_buf) {
+ command2 |= SLINK_RXEN;
+ tspi->cur_direction |= DATA_DIR_RX;
+ }
+ if (t->tx_buf) {
+ command2 |= SLINK_TXEN;
+ tspi->cur_direction |= DATA_DIR_TX;
+ }
+
+ /*
+ * Writing to the command2 register bevore the command register prevents
+ * a spike in chip_select line 0. This selects the chip_select line
+ * before changing the chip_select value.
+ */
+ tegra_slink_writel(tspi, command2, SLINK_COMMAND2);
+ tspi->command2_reg = command2;
+
+ tegra_slink_writel(tspi, command, SLINK_COMMAND);
+ tspi->command_reg = command;
+
+ if (total_fifo_words > SLINK_FIFO_DEPTH)
+ ret = tegra_slink_start_dma_based_transfer(tspi, t);
+ else
+ ret = tegra_slink_start_cpu_based_transfer(tspi, t);
+ return ret;
+}
+
+static int tegra_slink_setup(struct spi_device *spi)
+{
+ static const u32 cs_pol_bit[MAX_CHIP_SELECT] = {
+ SLINK_CS_POLARITY,
+ SLINK_CS_POLARITY1,
+ SLINK_CS_POLARITY2,
+ SLINK_CS_POLARITY3,
+ };
+
+ struct tegra_slink_data *tspi = spi_master_get_devdata(spi->master);
+ u32 val;
+ unsigned long flags;
+ int ret;
+
+ 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);
+
+ ret = pm_runtime_resume_and_get(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_command_reg;
+ if (spi->mode & SPI_CS_HIGH)
+ val |= cs_pol_bit[spi->chip_select];
+ else
+ val &= ~cs_pol_bit[spi->chip_select];
+ tspi->def_command_reg = val;
+ tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
+ spin_unlock_irqrestore(&tspi->lock, flags);
+
+ pm_runtime_put(tspi->dev);
+ return 0;
+}
+
+static int tegra_slink_prepare_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct tegra_slink_data *tspi = spi_master_get_devdata(master);
+ struct spi_device *spi = msg->spi;
+
+ tegra_slink_clear_status(tspi);
+
+ tspi->command_reg = tspi->def_command_reg;
+ tspi->command_reg |= SLINK_CS_SW | SLINK_CS_VALUE;
+
+ tspi->command2_reg = tspi->def_command2_reg;
+ tspi->command2_reg |= SLINK_SS_EN_CS(spi->chip_select);
+
+ tspi->command_reg &= ~SLINK_MODES;
+ if (spi->mode & SPI_CPHA)
+ tspi->command_reg |= SLINK_CK_SDA;
+
+ if (spi->mode & SPI_CPOL)
+ tspi->command_reg |= SLINK_IDLE_SCLK_DRIVE_HIGH;
+ else
+ tspi->command_reg |= SLINK_IDLE_SCLK_DRIVE_LOW;
+
+ return 0;
+}
+
+static int tegra_slink_transfer_one(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *xfer)
+{
+ struct tegra_slink_data *tspi = spi_master_get_devdata(master);
+ int ret;
+
+ reinit_completion(&tspi->xfer_completion);
+ ret = tegra_slink_start_transfer_one(spi, xfer);
+ if (ret < 0) {
+ dev_err(tspi->dev,
+ "spi can not start transfer, err %d\n", ret);
+ return ret;
+ }
+
+ ret = wait_for_completion_timeout(&tspi->xfer_completion,
+ SLINK_DMA_TIMEOUT);
+ if (WARN_ON(ret == 0)) {
+ dev_err(tspi->dev,
+ "spi transfer timeout, err %d\n", ret);
+ return -EIO;
+ }
+
+ if (tspi->tx_status)
+ return tspi->tx_status;
+ if (tspi->rx_status)
+ return tspi->rx_status;
+
+ return 0;
+}
+
+static int tegra_slink_unprepare_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct tegra_slink_data *tspi = spi_master_get_devdata(master);
+
+ tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
+ tegra_slink_writel(tspi, tspi->def_command2_reg, SLINK_COMMAND2);
+
+ return 0;
+}
+
+static irqreturn_t handle_cpu_based_xfer(struct tegra_slink_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 ||
+ (tspi->status_reg & SLINK_BSY)) {
+ dev_err(tspi->dev,
+ "CpuXfer ERROR bit set 0x%x\n", tspi->status_reg);
+ dev_err(tspi->dev,
+ "CpuXfer 0x%08x:0x%08x:0x%08x\n", tspi->command_reg,
+ tspi->command2_reg, tspi->dma_control_reg);
+ reset_control_assert(tspi->rst);
+ udelay(2);
+ reset_control_deassert(tspi->rst);
+ complete(&tspi->xfer_completion);
+ goto exit;
+ }
+
+ if (tspi->cur_direction & DATA_DIR_RX)
+ tegra_slink_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_slink_calculate_curr_xfer_param(tspi->cur_spi, tspi, t);
+ tegra_slink_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_slink_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, SLINK_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, SLINK_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:0x%08x\n", tspi->command_reg,
+ tspi->command2_reg, tspi->dma_control_reg);
+ reset_control_assert(tspi->rst);
+ udelay(2);
+ reset_control_assert(tspi->rst);
+ complete(&tspi->xfer_completion);
+ spin_unlock_irqrestore(&tspi->lock, flags);
+ return IRQ_HANDLED;
+ }
+
+ if (tspi->cur_direction & DATA_DIR_RX)
+ tegra_slink_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_slink_calculate_curr_xfer_param(tspi->cur_spi,
+ tspi, t);
+ if (total_fifo_words > SLINK_FIFO_DEPTH)
+ err = tegra_slink_start_dma_based_transfer(tspi, t);
+ else
+ err = tegra_slink_start_cpu_based_transfer(tspi, t);
+
+exit:
+ spin_unlock_irqrestore(&tspi->lock, flags);
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t tegra_slink_isr_thread(int irq, void *context_data)
+{
+ struct tegra_slink_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_slink_isr(int irq, void *context_data)
+{
+ struct tegra_slink_data *tspi = context_data;
+
+ tspi->status_reg = tegra_slink_readl(tspi, SLINK_STATUS);
+ if (tspi->cur_direction & DATA_DIR_TX)
+ tspi->tx_status = tspi->status_reg &
+ (SLINK_TX_OVF | SLINK_TX_UNF);
+
+ if (tspi->cur_direction & DATA_DIR_RX)
+ tspi->rx_status = tspi->status_reg &
+ (SLINK_RX_OVF | SLINK_RX_UNF);
+ tegra_slink_clear_status(tspi);
+
+ return IRQ_WAKE_THREAD;
+}
+
+static const struct tegra_slink_chip_data tegra30_spi_cdata = {
+ .cs_hold_time = true,
+};
+
+static const struct tegra_slink_chip_data tegra20_spi_cdata = {
+ .cs_hold_time = false,
+};
+
+static const struct of_device_id tegra_slink_of_match[] = {
+ { .compatible = "nvidia,tegra30-slink", .data = &tegra30_spi_cdata, },
+ { .compatible = "nvidia,tegra20-slink", .data = &tegra20_spi_cdata, },
+ {}
+};
+MODULE_DEVICE_TABLE(of, tegra_slink_of_match);
+
+static int tegra_slink_probe(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct tegra_slink_data *tspi;
+ struct resource *r;
+ int ret, spi_irq;
+ const struct tegra_slink_chip_data *cdata = NULL;
+
+ cdata = of_device_get_match_data(&pdev->dev);
+
+ master = spi_alloc_master(&pdev->dev, sizeof(*tspi));
+ 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 | SPI_CS_HIGH;
+ master->setup = tegra_slink_setup;
+ master->prepare_message = tegra_slink_prepare_message;
+ master->transfer_one = tegra_slink_transfer_one;
+ master->unprepare_message = tegra_slink_unprepare_message;
+ master->auto_runtime_pm = true;
+ master->num_chipselect = MAX_CHIP_SELECT;
+
+ platform_set_drvdata(pdev, master);
+ tspi = spi_master_get_devdata(master);
+ tspi->master = master;
+ tspi->dev = &pdev->dev;
+ tspi->chip_data = cdata;
+ spin_lock_init(&tspi->lock);
+
+ if (of_property_read_u32(tspi->dev->of_node, "spi-max-frequency",
+ &master->max_speed_hz))
+ master->max_speed_hz = 25000000; /* 25MHz */
+
+ 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);
+ goto exit_free_master;
+ }
+
+ /* disabled clock may cause interrupt storm upon request */
+ tspi->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(tspi->clk)) {
+ ret = PTR_ERR(tspi->clk);
+ dev_err(&pdev->dev, "Can not get clock %d\n", ret);
+ goto exit_free_master;
+ }
+
+ tspi->rst = devm_reset_control_get_exclusive(&pdev->dev, "spi");
+ if (IS_ERR(tspi->rst)) {
+ dev_err(&pdev->dev, "can not get reset\n");
+ ret = PTR_ERR(tspi->rst);
+ goto exit_free_master;
+ }
+
+ ret = devm_tegra_core_dev_init_opp_table_common(&pdev->dev);
+ if (ret)
+ goto exit_free_master;
+
+ tspi->max_buf_size = SLINK_FIFO_DEPTH << 2;
+ tspi->dma_buf_size = DEFAULT_SPI_DMA_BUF_LEN;
+
+ ret = tegra_slink_init_dma_param(tspi, true);
+ if (ret < 0)
+ goto exit_free_master;
+ ret = tegra_slink_init_dma_param(tspi, false);
+ if (ret < 0)
+ 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);
+ ret = pm_runtime_resume_and_get(&pdev->dev);
+ if (ret) {
+ dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret);
+ goto exit_pm_disable;
+ }
+
+ reset_control_assert(tspi->rst);
+ udelay(2);
+ reset_control_deassert(tspi->rst);
+
+ spi_irq = platform_get_irq(pdev, 0);
+ if (spi_irq < 0)
+ return spi_irq;
+ tspi->irq = spi_irq;
+ ret = request_threaded_irq(tspi->irq, tegra_slink_isr,
+ tegra_slink_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_pm_put;
+ }
+
+ tspi->def_command_reg = SLINK_M_S;
+ tspi->def_command2_reg = SLINK_CS_ACTIVE_BETWEEN;
+ tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
+ tegra_slink_writel(tspi, tspi->def_command2_reg, SLINK_COMMAND2);
+
+ 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_free_irq;
+ }
+
+ pm_runtime_put(&pdev->dev);
+
+ return ret;
+
+exit_free_irq:
+ free_irq(spi_irq, tspi);
+exit_pm_put:
+ pm_runtime_put(&pdev->dev);
+exit_pm_disable:
+ pm_runtime_force_suspend(&pdev->dev);
+
+ tegra_slink_deinit_dma_param(tspi, false);
+exit_rx_dma_free:
+ tegra_slink_deinit_dma_param(tspi, true);
+exit_free_master:
+ spi_master_put(master);
+ return ret;
+}
+
+static int tegra_slink_remove(struct platform_device *pdev)
+{
+ struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
+ struct tegra_slink_data *tspi = spi_master_get_devdata(master);
+
+ spi_unregister_master(master);
+
+ free_irq(tspi->irq, tspi);
+
+ pm_runtime_force_suspend(&pdev->dev);
+
+ if (tspi->tx_dma_chan)
+ tegra_slink_deinit_dma_param(tspi, false);
+
+ if (tspi->rx_dma_chan)
+ tegra_slink_deinit_dma_param(tspi, true);
+
+ spi_master_put(master);
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tegra_slink_suspend(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+
+ return spi_master_suspend(master);
+}
+
+static int tegra_slink_resume(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct tegra_slink_data *tspi = spi_master_get_devdata(master);
+ int ret;
+
+ ret = pm_runtime_resume_and_get(dev);
+ if (ret < 0) {
+ dev_err(dev, "pm runtime failed, e = %d\n", ret);
+ return ret;
+ }
+ tegra_slink_writel(tspi, tspi->command_reg, SLINK_COMMAND);
+ tegra_slink_writel(tspi, tspi->command2_reg, SLINK_COMMAND2);
+ pm_runtime_put(dev);
+
+ return spi_master_resume(master);
+}
+#endif
+
+static int __maybe_unused tegra_slink_runtime_suspend(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct tegra_slink_data *tspi = spi_master_get_devdata(master);
+
+ /* Flush all write which are in PPSB queue by reading back */
+ tegra_slink_readl(tspi, SLINK_MAS_DATA);
+
+ clk_disable_unprepare(tspi->clk);
+ return 0;
+}
+
+static int __maybe_unused tegra_slink_runtime_resume(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct tegra_slink_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 slink_pm_ops = {
+ SET_RUNTIME_PM_OPS(tegra_slink_runtime_suspend,
+ tegra_slink_runtime_resume, NULL)
+ SET_SYSTEM_SLEEP_PM_OPS(tegra_slink_suspend, tegra_slink_resume)
+};
+static struct platform_driver tegra_slink_driver = {
+ .driver = {
+ .name = "spi-tegra-slink",
+ .pm = &slink_pm_ops,
+ .of_match_table = tegra_slink_of_match,
+ },
+ .probe = tegra_slink_probe,
+ .remove = tegra_slink_remove,
+};
+module_platform_driver(tegra_slink_driver);
+
+MODULE_ALIAS("platform:spi-tegra-slink");
+MODULE_DESCRIPTION("NVIDIA Tegra20/Tegra30 SLINK Controller Driver");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_LICENSE("GPL v2");