spi: sprd: Add SPI driver for Spreadtrum SC9860
authorLanqing Liu <lanqing.liu@spreadtrum.com>
Thu, 16 Aug 2018 12:54:51 +0000 (20:54 +0800)
committerMark Brown <broonie@kernel.org>
Tue, 28 Aug 2018 20:19:20 +0000 (21:19 +0100)
This patch adds the SPI controller driver for Spreadtrum SC9860 platform.

Signed-off-by: Lanqing Liu <lanqing.liu@spreadtrum.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
drivers/spi/Kconfig
drivers/spi/Makefile
drivers/spi/spi-sprd.c [new file with mode: 0644]

index 671d078349cc667e32835ded589b145b3bb7d9a2..7580eb76ab18f71a99a5a7786caa1cf6c92b9e19 100644 (file)
@@ -596,6 +596,12 @@ config SPI_SIRF
        help
          SPI driver for CSR SiRFprimaII SoCs
 
+config SPI_SPRD
+       tristate "Spreadtrum SPI controller"
+       depends on ARCH_SPRD || COMPILE_TEST
+       help
+         SPI driver for Spreadtrum SoCs.
+
 config SPI_SPRD_ADI
        tristate "Spreadtrum ADI controller"
        depends on ARCH_SPRD || COMPILE_TEST
index a90d55970036536d4bedeccfe533864ddb02622e..1920b6cc2b7e4a9fdcf87e4ff80a8fefacb5c889 100644 (file)
@@ -88,6 +88,7 @@ obj-$(CONFIG_SPI_SH_HSPI)             += spi-sh-hspi.o
 obj-$(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-$(CONFIG_SPI_SPRD)                 += spi-sprd.o
 obj-$(CONFIG_SPI_SPRD_ADI)             += spi-sprd-adi.o
 obj-$(CONFIG_SPI_STM32)                += spi-stm32.o
 obj-$(CONFIG_SPI_ST_SSC4)              += spi-st-ssc4.o
diff --git a/drivers/spi/spi-sprd.c b/drivers/spi/spi-sprd.c
new file mode 100644 (file)
index 0000000..a9a6c5e
--- /dev/null
@@ -0,0 +1,745 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Spreadtrum Communications Inc.
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/spi/spi.h>
+
+#define SPRD_SPI_TXD                   0x0
+#define SPRD_SPI_CLKD                  0x4
+#define SPRD_SPI_CTL0                  0x8
+#define SPRD_SPI_CTL1                  0xc
+#define SPRD_SPI_CTL2                  0x10
+#define SPRD_SPI_CTL3                  0x14
+#define SPRD_SPI_CTL4                  0x18
+#define SPRD_SPI_CTL5                  0x1c
+#define SPRD_SPI_INT_EN                        0x20
+#define SPRD_SPI_INT_CLR               0x24
+#define SPRD_SPI_INT_RAW_STS           0x28
+#define SPRD_SPI_INT_MASK_STS          0x2c
+#define SPRD_SPI_STS1                  0x30
+#define SPRD_SPI_STS2                  0x34
+#define SPRD_SPI_DSP_WAIT              0x38
+#define SPRD_SPI_STS3                  0x3c
+#define SPRD_SPI_CTL6                  0x40
+#define SPRD_SPI_STS4                  0x44
+#define SPRD_SPI_FIFO_RST              0x48
+#define SPRD_SPI_CTL7                  0x4c
+#define SPRD_SPI_STS5                  0x50
+#define SPRD_SPI_CTL8                  0x54
+#define SPRD_SPI_CTL9                  0x58
+#define SPRD_SPI_CTL10                 0x5c
+#define SPRD_SPI_CTL11                 0x60
+#define SPRD_SPI_CTL12                 0x64
+#define SPRD_SPI_STS6                  0x68
+#define SPRD_SPI_STS7                  0x6c
+#define SPRD_SPI_STS8                  0x70
+#define SPRD_SPI_STS9                  0x74
+
+/* Bits & mask definition for register CTL0 */
+#define SPRD_SPI_SCK_REV               BIT(13)
+#define SPRD_SPI_NG_TX                 BIT(1)
+#define SPRD_SPI_NG_RX                 BIT(0)
+#define SPRD_SPI_CHNL_LEN_MASK         GENMASK(4, 0)
+#define SPRD_SPI_CSN_MASK              GENMASK(11, 8)
+#define SPRD_SPI_CS0_VALID             BIT(8)
+
+/* Bits & mask definition for register SPI_INT_EN */
+#define SPRD_SPI_TX_END_INT_EN         BIT(8)
+#define SPRD_SPI_RX_END_INT_EN         BIT(9)
+
+/* Bits & mask definition for register SPI_INT_RAW_STS */
+#define SPRD_SPI_TX_END_RAW            BIT(8)
+#define SPRD_SPI_RX_END_RAW            BIT(9)
+
+/* Bits & mask definition for register SPI_INT_CLR */
+#define SPRD_SPI_TX_END_CLR            BIT(8)
+#define SPRD_SPI_RX_END_CLR            BIT(9)
+
+/* Bits & mask definition for register INT_MASK_STS */
+#define SPRD_SPI_MASK_RX_END           BIT(9)
+#define SPRD_SPI_MASK_TX_END           BIT(8)
+
+/* Bits & mask definition for register STS2 */
+#define SPRD_SPI_TX_BUSY               BIT(8)
+
+/* Bits & mask definition for register CTL1 */
+#define SPRD_SPI_RX_MODE               BIT(12)
+#define SPRD_SPI_TX_MODE               BIT(13)
+#define SPRD_SPI_RTX_MD_MASK           GENMASK(13, 12)
+
+/* Bits & mask definition for register CTL2 */
+#define SPRD_SPI_DMA_EN                        BIT(6)
+
+/* Bits & mask definition for register CTL4 */
+#define SPRD_SPI_START_RX              BIT(9)
+#define SPRD_SPI_ONLY_RECV_MASK                GENMASK(8, 0)
+
+/* Bits & mask definition for register SPI_INT_CLR */
+#define SPRD_SPI_RX_END_INT_CLR                BIT(9)
+#define SPRD_SPI_TX_END_INT_CLR                BIT(8)
+
+/* Bits & mask definition for register SPI_INT_RAW */
+#define SPRD_SPI_RX_END_IRQ            BIT(9)
+#define SPRD_SPI_TX_END_IRQ            BIT(8)
+
+/* Bits & mask definition for register CTL12 */
+#define SPRD_SPI_SW_RX_REQ             BIT(0)
+#define SPRD_SPI_SW_TX_REQ             BIT(1)
+
+/* Bits & mask definition for register CTL7 */
+#define SPRD_SPI_DATA_LINE2_EN         BIT(15)
+#define SPRD_SPI_MODE_MASK             GENMASK(5, 3)
+#define SPRD_SPI_MODE_OFFSET           3
+#define SPRD_SPI_3WIRE_MODE            4
+#define SPRD_SPI_4WIRE_MODE            0
+
+/* Bits & mask definition for register CTL8 */
+#define SPRD_SPI_TX_MAX_LEN_MASK       GENMASK(19, 0)
+#define SPRD_SPI_TX_LEN_H_MASK         GENMASK(3, 0)
+#define SPRD_SPI_TX_LEN_H_OFFSET       16
+
+/* Bits & mask definition for register CTL9 */
+#define SPRD_SPI_TX_LEN_L_MASK         GENMASK(15, 0)
+
+/* Bits & mask definition for register CTL10 */
+#define SPRD_SPI_RX_MAX_LEN_MASK       GENMASK(19, 0)
+#define SPRD_SPI_RX_LEN_H_MASK         GENMASK(3, 0)
+#define SPRD_SPI_RX_LEN_H_OFFSET       16
+
+/* Bits & mask definition for register CTL11 */
+#define SPRD_SPI_RX_LEN_L_MASK         GENMASK(15, 0)
+
+/* Default & maximum word delay cycles */
+#define SPRD_SPI_MIN_DELAY_CYCLE       14
+#define SPRD_SPI_MAX_DELAY_CYCLE       130
+
+#define SPRD_SPI_FIFO_SIZE             32
+#define SPRD_SPI_CHIP_CS_NUM           0x4
+#define SPRD_SPI_CHNL_LEN              2
+#define SPRD_SPI_DEFAULT_SOURCE                26000000
+#define SPRD_SPI_MAX_SPEED_HZ          48000000
+#define SPRD_SPI_AUTOSUSPEND_DELAY     100
+
+struct sprd_spi {
+       void __iomem *base;
+       struct device *dev;
+       struct clk *clk;
+       u32 src_clk;
+       u32 hw_mode;
+       u32 trans_len;
+       u32 trans_mode;
+       u32 word_delay;
+       u32 hw_speed_hz;
+       u32 len;
+       int status;
+       const void *tx_buf;
+       void *rx_buf;
+       int (*read_bufs)(struct sprd_spi *ss, u32 len);
+       int (*write_bufs)(struct sprd_spi *ss, u32 len);
+};
+
+static u32 sprd_spi_transfer_max_timeout(struct sprd_spi *ss,
+                                        struct spi_transfer *t)
+{
+       /*
+        * The time spent on transmission of the full FIFO data is the maximum
+        * SPI transmission time.
+        */
+       u32 size = t->bits_per_word * SPRD_SPI_FIFO_SIZE;
+       u32 bit_time_us = DIV_ROUND_UP(USEC_PER_SEC, ss->hw_speed_hz);
+       u32 total_time_us = size * bit_time_us;
+       /*
+        * There is an interval between data and the data in our SPI hardware,
+        * so the total transmission time need add the interval time.
+        */
+       u32 interval_cycle = SPRD_SPI_FIFO_SIZE * ss->word_delay;
+       u32 interval_time_us = DIV_ROUND_UP(interval_cycle * USEC_PER_SEC,
+                                           ss->src_clk);
+
+       return total_time_us + interval_time_us;
+}
+
+static int sprd_spi_wait_for_tx_end(struct sprd_spi *ss, struct spi_transfer *t)
+{
+       u32 val, us;
+       int ret;
+
+       us = sprd_spi_transfer_max_timeout(ss, t);
+       ret = readl_relaxed_poll_timeout(ss->base + SPRD_SPI_INT_RAW_STS, val,
+                                        val & SPRD_SPI_TX_END_IRQ, 0, us);
+       if (ret) {
+               dev_err(ss->dev, "SPI error, spi send timeout!\n");
+               return ret;
+       }
+
+       ret = readl_relaxed_poll_timeout(ss->base + SPRD_SPI_STS2, val,
+                                        !(val & SPRD_SPI_TX_BUSY), 0, us);
+       if (ret) {
+               dev_err(ss->dev, "SPI error, spi busy timeout!\n");
+               return ret;
+       }
+
+       writel_relaxed(SPRD_SPI_TX_END_INT_CLR, ss->base + SPRD_SPI_INT_CLR);
+
+       return 0;
+}
+
+static int sprd_spi_wait_for_rx_end(struct sprd_spi *ss, struct spi_transfer *t)
+{
+       u32 val, us;
+       int ret;
+
+       us = sprd_spi_transfer_max_timeout(ss, t);
+       ret = readl_relaxed_poll_timeout(ss->base + SPRD_SPI_INT_RAW_STS, val,
+                                        val & SPRD_SPI_RX_END_IRQ, 0, us);
+       if (ret) {
+               dev_err(ss->dev, "SPI error, spi rx timeout!\n");
+               return ret;
+       }
+
+       writel_relaxed(SPRD_SPI_RX_END_INT_CLR, ss->base + SPRD_SPI_INT_CLR);
+
+       return 0;
+}
+
+static void sprd_spi_tx_req(struct sprd_spi *ss)
+{
+       writel_relaxed(SPRD_SPI_SW_TX_REQ, ss->base + SPRD_SPI_CTL12);
+}
+
+static void sprd_spi_rx_req(struct sprd_spi *ss)
+{
+       writel_relaxed(SPRD_SPI_SW_RX_REQ, ss->base + SPRD_SPI_CTL12);
+}
+
+static void sprd_spi_enter_idle(struct sprd_spi *ss)
+{
+       u32 val = readl_relaxed(ss->base + SPRD_SPI_CTL1);
+
+       val &= ~SPRD_SPI_RTX_MD_MASK;
+       writel_relaxed(val, ss->base + SPRD_SPI_CTL1);
+}
+
+static void sprd_spi_set_transfer_bits(struct sprd_spi *ss, u32 bits)
+{
+       u32 val = readl_relaxed(ss->base + SPRD_SPI_CTL0);
+
+       /* Set the valid bits for every transaction */
+       val &= ~(SPRD_SPI_CHNL_LEN_MASK << SPRD_SPI_CHNL_LEN);
+       val |= bits << SPRD_SPI_CHNL_LEN;
+       writel_relaxed(val, ss->base + SPRD_SPI_CTL0);
+}
+
+static void sprd_spi_set_tx_length(struct sprd_spi *ss, u32 length)
+{
+       u32 val = readl_relaxed(ss->base + SPRD_SPI_CTL8);
+
+       length &= SPRD_SPI_TX_MAX_LEN_MASK;
+       val &= ~SPRD_SPI_TX_LEN_H_MASK;
+       val |= length >> SPRD_SPI_TX_LEN_H_OFFSET;
+       writel_relaxed(val, ss->base + SPRD_SPI_CTL8);
+
+       val = length & SPRD_SPI_TX_LEN_L_MASK;
+       writel_relaxed(val, ss->base + SPRD_SPI_CTL9);
+}
+
+static void sprd_spi_set_rx_length(struct sprd_spi *ss, u32 length)
+{
+       u32 val = readl_relaxed(ss->base + SPRD_SPI_CTL10);
+
+       length &= SPRD_SPI_RX_MAX_LEN_MASK;
+       val &= ~SPRD_SPI_RX_LEN_H_MASK;
+       val |= length >> SPRD_SPI_RX_LEN_H_OFFSET;
+       writel_relaxed(val, ss->base + SPRD_SPI_CTL10);
+
+       val = length & SPRD_SPI_RX_LEN_L_MASK;
+       writel_relaxed(val, ss->base + SPRD_SPI_CTL11);
+}
+
+static void sprd_spi_chipselect(struct spi_device *sdev, bool cs)
+{
+       struct spi_controller *sctlr = sdev->controller;
+       struct sprd_spi *ss = spi_controller_get_devdata(sctlr);
+       u32 val;
+
+       val = readl_relaxed(ss->base + SPRD_SPI_CTL0);
+       /*  The SPI controller will pull down CS pin if cs is 0 */
+       if (!cs) {
+               val &= ~SPRD_SPI_CS0_VALID;
+               writel_relaxed(val, ss->base + SPRD_SPI_CTL0);
+       } else {
+               val |= SPRD_SPI_CSN_MASK;
+               writel_relaxed(val, ss->base + SPRD_SPI_CTL0);
+       }
+}
+
+static int sprd_spi_write_only_receive(struct sprd_spi *ss, u32 len)
+{
+       u32 val;
+
+       /* Clear the start receive bit and reset receive data number */
+       val = readl_relaxed(ss->base + SPRD_SPI_CTL4);
+       val &= ~(SPRD_SPI_START_RX | SPRD_SPI_ONLY_RECV_MASK);
+       writel_relaxed(val, ss->base + SPRD_SPI_CTL4);
+
+       /* Set the receive data length */
+       val = readl_relaxed(ss->base + SPRD_SPI_CTL4);
+       val |= len & SPRD_SPI_ONLY_RECV_MASK;
+       writel_relaxed(val, ss->base + SPRD_SPI_CTL4);
+
+       /* Trigger to receive data */
+       val = readl_relaxed(ss->base + SPRD_SPI_CTL4);
+       val |= SPRD_SPI_START_RX;
+       writel_relaxed(val, ss->base + SPRD_SPI_CTL4);
+
+       return len;
+}
+
+static int sprd_spi_write_bufs_u8(struct sprd_spi *ss, u32 len)
+{
+       u8 *tx_p = (u8 *)ss->tx_buf;
+       int i;
+
+       for (i = 0; i < len; i++)
+               writeb_relaxed(tx_p[i], ss->base + SPRD_SPI_TXD);
+
+       ss->tx_buf += i;
+       return i;
+}
+
+static int sprd_spi_write_bufs_u16(struct sprd_spi *ss, u32 len)
+{
+       u16 *tx_p = (u16 *)ss->tx_buf;
+       int i;
+
+       for (i = 0; i < len; i++)
+               writew_relaxed(tx_p[i], ss->base + SPRD_SPI_TXD);
+
+       ss->tx_buf += i << 1;
+       return i << 1;
+}
+
+static int sprd_spi_write_bufs_u32(struct sprd_spi *ss, u32 len)
+{
+       u32 *tx_p = (u32 *)ss->tx_buf;
+       int i;
+
+       for (i = 0; i < len; i++)
+               writel_relaxed(tx_p[i], ss->base + SPRD_SPI_TXD);
+
+       ss->tx_buf += i << 2;
+       return i << 2;
+}
+
+static int sprd_spi_read_bufs_u8(struct sprd_spi *ss, u32 len)
+{
+       u8 *rx_p = (u8 *)ss->rx_buf;
+       int i;
+
+       for (i = 0; i < len; i++)
+               rx_p[i] = readb_relaxed(ss->base + SPRD_SPI_TXD);
+
+       ss->rx_buf += i;
+       return i;
+}
+
+static int sprd_spi_read_bufs_u16(struct sprd_spi *ss, u32 len)
+{
+       u16 *rx_p = (u16 *)ss->rx_buf;
+       int i;
+
+       for (i = 0; i < len; i++)
+               rx_p[i] = readw_relaxed(ss->base + SPRD_SPI_TXD);
+
+       ss->rx_buf += i << 1;
+       return i << 1;
+}
+
+static int sprd_spi_read_bufs_u32(struct sprd_spi *ss, u32 len)
+{
+       u32 *rx_p = (u32 *)ss->rx_buf;
+       int i;
+
+       for (i = 0; i < len; i++)
+               rx_p[i] = readl_relaxed(ss->base + SPRD_SPI_TXD);
+
+       ss->rx_buf += i << 2;
+       return i << 2;
+}
+
+static int sprd_spi_txrx_bufs(struct spi_device *sdev, struct spi_transfer *t)
+{
+       struct sprd_spi *ss = spi_controller_get_devdata(sdev->controller);
+       u32 trans_len = ss->trans_len, len;
+       int ret, write_size = 0;
+
+       while (trans_len) {
+               len = trans_len > SPRD_SPI_FIFO_SIZE ? SPRD_SPI_FIFO_SIZE :
+                       trans_len;
+               if (ss->trans_mode & SPRD_SPI_TX_MODE) {
+                       sprd_spi_set_tx_length(ss, len);
+                       write_size += ss->write_bufs(ss, len);
+
+                       /*
+                        * For our 3 wires mode or dual TX line mode, we need
+                        * to request the controller to transfer.
+                        */
+                       if (ss->hw_mode & SPI_3WIRE || ss->hw_mode & SPI_TX_DUAL)
+                               sprd_spi_tx_req(ss);
+
+                       ret = sprd_spi_wait_for_tx_end(ss, t);
+               } else {
+                       sprd_spi_set_rx_length(ss, len);
+
+                       /*
+                        * For our 3 wires mode or dual TX line mode, we need
+                        * to request the controller to read.
+                        */
+                       if (ss->hw_mode & SPI_3WIRE || ss->hw_mode & SPI_TX_DUAL)
+                               sprd_spi_rx_req(ss);
+                       else
+                               write_size += ss->write_bufs(ss, len);
+
+                       ret = sprd_spi_wait_for_rx_end(ss, t);
+               }
+
+               if (ret)
+                       goto complete;
+
+               if (ss->trans_mode & SPRD_SPI_RX_MODE)
+                       ss->read_bufs(ss, len);
+
+               trans_len -= len;
+       }
+
+       ret = write_size;
+
+complete:
+       sprd_spi_enter_idle(ss);
+
+       return ret;
+}
+
+static void sprd_spi_set_speed(struct sprd_spi *ss, u32 speed_hz)
+{
+       /*
+        * From SPI datasheet, the prescale calculation formula:
+        * prescale = SPI source clock / (2 * SPI_freq) - 1;
+        */
+       u32 clk_div = DIV_ROUND_UP(ss->src_clk, speed_hz << 1) - 1;
+
+       /* Save the real hardware speed */
+       ss->hw_speed_hz = (ss->src_clk >> 1) / (clk_div + 1);
+       writel_relaxed(clk_div, ss->base + SPRD_SPI_CLKD);
+}
+
+static void sprd_spi_init_hw(struct sprd_spi *ss, struct spi_transfer *t)
+{
+       u16 word_delay, interval;
+       u32 val;
+
+       val = readl_relaxed(ss->base + SPRD_SPI_CTL7);
+       val &= ~(SPRD_SPI_SCK_REV | SPRD_SPI_NG_TX | SPRD_SPI_NG_RX);
+       /* Set default chip selection, clock phase and clock polarity */
+       val |= ss->hw_mode & SPI_CPHA ? SPRD_SPI_NG_RX : SPRD_SPI_NG_TX;
+       val |= ss->hw_mode & SPI_CPOL ? SPRD_SPI_SCK_REV : 0;
+       writel_relaxed(val, ss->base + SPRD_SPI_CTL0);
+
+       /*
+        * Set the intervals of two SPI frames, and the inteval calculation
+        * formula as below per datasheet:
+        * interval time (source clock cycles) = interval * 4 + 10.
+        */
+       word_delay = clamp_t(u16, t->word_delay, SPRD_SPI_MIN_DELAY_CYCLE,
+                            SPRD_SPI_MAX_DELAY_CYCLE);
+       interval = DIV_ROUND_UP(word_delay - 10, 4);
+       ss->word_delay = interval * 4 + 10;
+       writel_relaxed(interval, ss->base + SPRD_SPI_CTL5);
+
+       /* Reset SPI fifo */
+       writel_relaxed(1, ss->base + SPRD_SPI_FIFO_RST);
+       writel_relaxed(0, ss->base + SPRD_SPI_FIFO_RST);
+
+       /* Set SPI work mode */
+       val = readl_relaxed(ss->base + SPRD_SPI_CTL7);
+       val &= ~SPRD_SPI_MODE_MASK;
+
+       if (ss->hw_mode & SPI_3WIRE)
+               val |= SPRD_SPI_3WIRE_MODE << SPRD_SPI_MODE_OFFSET;
+       else
+               val |= SPRD_SPI_4WIRE_MODE << SPRD_SPI_MODE_OFFSET;
+
+       if (ss->hw_mode & SPI_TX_DUAL)
+               val |= SPRD_SPI_DATA_LINE2_EN;
+       else
+               val &= ~SPRD_SPI_DATA_LINE2_EN;
+
+       writel_relaxed(val, ss->base + SPRD_SPI_CTL7);
+}
+
+static int sprd_spi_setup_transfer(struct spi_device *sdev,
+                                  struct spi_transfer *t)
+{
+       struct sprd_spi *ss = spi_controller_get_devdata(sdev->controller);
+       u8 bits_per_word = t->bits_per_word;
+       u32 val, mode = 0;
+
+       ss->len = t->len;
+       ss->tx_buf = t->tx_buf;
+       ss->rx_buf = t->rx_buf;
+
+       ss->hw_mode = sdev->mode;
+       sprd_spi_init_hw(ss, t);
+
+       /* Set tansfer speed and valid bits */
+       sprd_spi_set_speed(ss, t->speed_hz);
+       sprd_spi_set_transfer_bits(ss, bits_per_word);
+
+       if (bits_per_word > 16)
+               bits_per_word = round_up(bits_per_word, 16);
+       else
+               bits_per_word = round_up(bits_per_word, 8);
+
+       switch (bits_per_word) {
+       case 8:
+               ss->trans_len = t->len;
+               ss->read_bufs = sprd_spi_read_bufs_u8;
+               ss->write_bufs = sprd_spi_write_bufs_u8;
+               break;
+       case 16:
+               ss->trans_len = t->len >> 1;
+               ss->read_bufs = sprd_spi_read_bufs_u16;
+               ss->write_bufs = sprd_spi_write_bufs_u16;
+               break;
+       case 32:
+               ss->trans_len = t->len >> 2;
+               ss->read_bufs = sprd_spi_read_bufs_u32;
+               ss->write_bufs = sprd_spi_write_bufs_u32;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       /* Set transfer read or write mode */
+       val = readl_relaxed(ss->base + SPRD_SPI_CTL1);
+       val &= ~SPRD_SPI_RTX_MD_MASK;
+       if (t->tx_buf)
+               mode |= SPRD_SPI_TX_MODE;
+       if (t->rx_buf)
+               mode |= SPRD_SPI_RX_MODE;
+
+       writel_relaxed(val | mode, ss->base + SPRD_SPI_CTL1);
+
+       ss->trans_mode = mode;
+
+       /*
+        * If in only receive mode, we need to trigger the SPI controller to
+        * receive data automatically.
+        */
+       if (ss->trans_mode == SPRD_SPI_RX_MODE)
+               ss->write_bufs = sprd_spi_write_only_receive;
+
+       return 0;
+}
+
+static int sprd_spi_transfer_one(struct spi_controller *sctlr,
+                                struct spi_device *sdev,
+                                struct spi_transfer *t)
+{
+       int ret;
+
+       ret = sprd_spi_setup_transfer(sdev, t);
+       if (ret)
+               goto setup_err;
+
+       ret = sprd_spi_txrx_bufs(sdev, t);
+       if (ret == t->len)
+               ret = 0;
+       else if (ret >= 0)
+               ret = -EREMOTEIO;
+
+setup_err:
+       spi_finalize_current_transfer(sctlr);
+
+       return ret;
+}
+
+static int sprd_spi_clk_init(struct platform_device *pdev, struct sprd_spi *ss)
+{
+       struct clk *clk_spi, *clk_parent;
+
+       clk_spi = devm_clk_get(&pdev->dev, "spi");
+       if (IS_ERR(clk_spi)) {
+               dev_warn(&pdev->dev, "can't get the spi clock\n");
+               clk_spi = NULL;
+       }
+
+       clk_parent = devm_clk_get(&pdev->dev, "source");
+       if (IS_ERR(clk_parent)) {
+               dev_warn(&pdev->dev, "can't get the source clock\n");
+               clk_parent = NULL;
+       }
+
+       ss->clk = devm_clk_get(&pdev->dev, "enable");
+       if (IS_ERR(ss->clk)) {
+               dev_err(&pdev->dev, "can't get the enable clock\n");
+               return PTR_ERR(ss->clk);
+       }
+
+       if (!clk_set_parent(clk_spi, clk_parent))
+               ss->src_clk = clk_get_rate(clk_spi);
+       else
+               ss->src_clk = SPRD_SPI_DEFAULT_SOURCE;
+
+       return 0;
+}
+
+static int sprd_spi_probe(struct platform_device *pdev)
+{
+       struct spi_controller *sctlr;
+       struct resource *res;
+       struct sprd_spi *ss;
+       int ret;
+
+       pdev->id = of_alias_get_id(pdev->dev.of_node, "spi");
+       sctlr = spi_alloc_master(&pdev->dev, sizeof(*ss));
+       if (!sctlr)
+               return -ENOMEM;
+
+       ss = spi_controller_get_devdata(sctlr);
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       ss->base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(ss->base)) {
+               ret = PTR_ERR(ss->base);
+               goto free_controller;
+       }
+
+       ss->dev = &pdev->dev;
+       sctlr->dev.of_node = pdev->dev.of_node;
+       sctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_3WIRE | SPI_TX_DUAL;
+       sctlr->bus_num = pdev->id;
+       sctlr->set_cs = sprd_spi_chipselect;
+       sctlr->transfer_one = sprd_spi_transfer_one;
+       sctlr->auto_runtime_pm = true;
+       sctlr->max_speed_hz = min_t(u32, ss->src_clk >> 1,
+                                   SPRD_SPI_MAX_SPEED_HZ);
+
+       platform_set_drvdata(pdev, sctlr);
+       ret = sprd_spi_clk_init(pdev, ss);
+       if (ret)
+               goto free_controller;
+
+       ret = clk_prepare_enable(ss->clk);
+       if (ret)
+               goto free_controller;
+
+       ret = pm_runtime_set_active(&pdev->dev);
+       if (ret < 0)
+               goto disable_clk;
+
+       pm_runtime_set_autosuspend_delay(&pdev->dev,
+                                        SPRD_SPI_AUTOSUSPEND_DELAY);
+       pm_runtime_use_autosuspend(&pdev->dev);
+       pm_runtime_enable(&pdev->dev);
+       ret = pm_runtime_get_sync(&pdev->dev);
+       if (ret < 0) {
+               dev_err(&pdev->dev, "failed to resume SPI controller\n");
+               goto err_rpm_put;
+       }
+
+       ret = devm_spi_register_controller(&pdev->dev, sctlr);
+       if (ret)
+               goto err_rpm_put;
+
+       pm_runtime_mark_last_busy(&pdev->dev);
+       pm_runtime_put_autosuspend(&pdev->dev);
+
+       return 0;
+
+err_rpm_put:
+       pm_runtime_put_noidle(&pdev->dev);
+       pm_runtime_disable(&pdev->dev);
+disable_clk:
+       clk_disable_unprepare(ss->clk);
+free_controller:
+       spi_controller_put(sctlr);
+
+       return ret;
+}
+
+static int __exit sprd_spi_remove(struct platform_device *pdev)
+{
+       struct spi_controller *sctlr = platform_get_drvdata(pdev);
+       struct sprd_spi *ss = spi_controller_get_devdata(sctlr);
+       int ret;
+
+       ret = pm_runtime_get_sync(ss->dev);
+       if (ret < 0) {
+               dev_err(ss->dev, "failed to resume SPI controller\n");
+               return ret;
+       }
+
+       clk_disable_unprepare(ss->clk);
+       pm_runtime_put_noidle(&pdev->dev);
+       pm_runtime_disable(&pdev->dev);
+
+       return 0;
+}
+
+static int __maybe_unused sprd_spi_runtime_suspend(struct device *dev)
+{
+       struct spi_controller *sctlr = dev_get_drvdata(dev);
+       struct sprd_spi *ss = spi_controller_get_devdata(sctlr);
+
+       clk_disable_unprepare(ss->clk);
+
+       return 0;
+}
+
+static int __maybe_unused sprd_spi_runtime_resume(struct device *dev)
+{
+       struct spi_controller *sctlr = dev_get_drvdata(dev);
+       struct sprd_spi *ss = spi_controller_get_devdata(sctlr);
+       int ret;
+
+       ret = clk_prepare_enable(ss->clk);
+       if (ret)
+               return ret;
+
+       return 0;
+}
+
+static const struct dev_pm_ops sprd_spi_pm_ops = {
+       SET_RUNTIME_PM_OPS(sprd_spi_runtime_suspend,
+                          sprd_spi_runtime_resume, NULL)
+};
+
+static const struct of_device_id sprd_spi_of_match[] = {
+       { .compatible = "sprd,sc9860-spi", },
+       { /* sentinel */ }
+};
+
+static struct platform_driver sprd_spi_driver = {
+       .driver = {
+               .name = "sprd-spi",
+               .of_match_table = sprd_spi_of_match,
+               .pm = &sprd_spi_pm_ops,
+       },
+       .probe = sprd_spi_probe,
+       .remove  = sprd_spi_remove,
+};
+
+module_platform_driver(sprd_spi_driver);
+
+MODULE_DESCRIPTION("Spreadtrum SPI Controller driver");
+MODULE_AUTHOR("Lanqing Liu <lanqing.liu@spreadtrum.com>");
+MODULE_LICENSE("GPL v2");