diff options
Diffstat (limited to 'drivers/spi/spi-armada-3700.c')
| -rw-r--r-- | drivers/spi/spi-armada-3700.c | 935 |
1 files changed, 935 insertions, 0 deletions
diff --git a/drivers/spi/spi-armada-3700.c b/drivers/spi/spi-armada-3700.c new file mode 100644 index 000000000..9df9fc40b --- /dev/null +++ b/drivers/spi/spi-armada-3700.c @@ -0,0 +1,935 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Marvell Armada-3700 SPI controller driver + * + * Copyright (C) 2016 Marvell Ltd. + * + * Author: Wilson Ding <dingwei@marvell.com> + * Author: Romain Perier <romain.perier@free-electrons.com> + */ + +#include <linux/clk.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/of_device.h> +#include <linux/pinctrl/consumer.h> +#include <linux/spi/spi.h> + +#define DRIVER_NAME "armada_3700_spi" + +#define A3700_SPI_MAX_SPEED_HZ 100000000 +#define A3700_SPI_MAX_PRESCALE 30 +#define A3700_SPI_TIMEOUT 10 + +/* SPI Register Offest */ +#define A3700_SPI_IF_CTRL_REG 0x00 +#define A3700_SPI_IF_CFG_REG 0x04 +#define A3700_SPI_DATA_OUT_REG 0x08 +#define A3700_SPI_DATA_IN_REG 0x0C +#define A3700_SPI_IF_INST_REG 0x10 +#define A3700_SPI_IF_ADDR_REG 0x14 +#define A3700_SPI_IF_RMODE_REG 0x18 +#define A3700_SPI_IF_HDR_CNT_REG 0x1C +#define A3700_SPI_IF_DIN_CNT_REG 0x20 +#define A3700_SPI_IF_TIME_REG 0x24 +#define A3700_SPI_INT_STAT_REG 0x28 +#define A3700_SPI_INT_MASK_REG 0x2C + +/* A3700_SPI_IF_CTRL_REG */ +#define A3700_SPI_EN BIT(16) +#define A3700_SPI_ADDR_NOT_CONFIG BIT(12) +#define A3700_SPI_WFIFO_OVERFLOW BIT(11) +#define A3700_SPI_WFIFO_UNDERFLOW BIT(10) +#define A3700_SPI_RFIFO_OVERFLOW BIT(9) +#define A3700_SPI_RFIFO_UNDERFLOW BIT(8) +#define A3700_SPI_WFIFO_FULL BIT(7) +#define A3700_SPI_WFIFO_EMPTY BIT(6) +#define A3700_SPI_RFIFO_FULL BIT(5) +#define A3700_SPI_RFIFO_EMPTY BIT(4) +#define A3700_SPI_WFIFO_RDY BIT(3) +#define A3700_SPI_RFIFO_RDY BIT(2) +#define A3700_SPI_XFER_RDY BIT(1) +#define A3700_SPI_XFER_DONE BIT(0) + +/* A3700_SPI_IF_CFG_REG */ +#define A3700_SPI_WFIFO_THRS BIT(28) +#define A3700_SPI_RFIFO_THRS BIT(24) +#define A3700_SPI_AUTO_CS BIT(20) +#define A3700_SPI_DMA_RD_EN BIT(18) +#define A3700_SPI_FIFO_MODE BIT(17) +#define A3700_SPI_SRST BIT(16) +#define A3700_SPI_XFER_START BIT(15) +#define A3700_SPI_XFER_STOP BIT(14) +#define A3700_SPI_INST_PIN BIT(13) +#define A3700_SPI_ADDR_PIN BIT(12) +#define A3700_SPI_DATA_PIN1 BIT(11) +#define A3700_SPI_DATA_PIN0 BIT(10) +#define A3700_SPI_FIFO_FLUSH BIT(9) +#define A3700_SPI_RW_EN BIT(8) +#define A3700_SPI_CLK_POL BIT(7) +#define A3700_SPI_CLK_PHA BIT(6) +#define A3700_SPI_BYTE_LEN BIT(5) +#define A3700_SPI_CLK_PRESCALE BIT(0) +#define A3700_SPI_CLK_PRESCALE_MASK (0x1f) +#define A3700_SPI_CLK_EVEN_OFFS (0x10) + +#define A3700_SPI_WFIFO_THRS_BIT 28 +#define A3700_SPI_RFIFO_THRS_BIT 24 +#define A3700_SPI_FIFO_THRS_MASK 0x7 + +#define A3700_SPI_DATA_PIN_MASK 0x3 + +/* A3700_SPI_IF_HDR_CNT_REG */ +#define A3700_SPI_DUMMY_CNT_BIT 12 +#define A3700_SPI_DUMMY_CNT_MASK 0x7 +#define A3700_SPI_RMODE_CNT_BIT 8 +#define A3700_SPI_RMODE_CNT_MASK 0x3 +#define A3700_SPI_ADDR_CNT_BIT 4 +#define A3700_SPI_ADDR_CNT_MASK 0x7 +#define A3700_SPI_INSTR_CNT_BIT 0 +#define A3700_SPI_INSTR_CNT_MASK 0x3 + +/* A3700_SPI_IF_TIME_REG */ +#define A3700_SPI_CLK_CAPT_EDGE BIT(7) + +struct a3700_spi { + struct spi_master *master; + void __iomem *base; + struct clk *clk; + unsigned int irq; + unsigned int flags; + bool xmit_data; + const u8 *tx_buf; + u8 *rx_buf; + size_t buf_len; + u8 byte_len; + u32 wait_mask; + struct completion done; +}; + +static u32 spireg_read(struct a3700_spi *a3700_spi, u32 offset) +{ + return readl(a3700_spi->base + offset); +} + +static void spireg_write(struct a3700_spi *a3700_spi, u32 offset, u32 data) +{ + writel(data, a3700_spi->base + offset); +} + +static void a3700_spi_auto_cs_unset(struct a3700_spi *a3700_spi) +{ + u32 val; + + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + val &= ~A3700_SPI_AUTO_CS; + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); +} + +static void a3700_spi_activate_cs(struct a3700_spi *a3700_spi, unsigned int cs) +{ + u32 val; + + val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG); + val |= (A3700_SPI_EN << cs); + spireg_write(a3700_spi, A3700_SPI_IF_CTRL_REG, val); +} + +static void a3700_spi_deactivate_cs(struct a3700_spi *a3700_spi, + unsigned int cs) +{ + u32 val; + + val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG); + val &= ~(A3700_SPI_EN << cs); + spireg_write(a3700_spi, A3700_SPI_IF_CTRL_REG, val); +} + +static int a3700_spi_pin_mode_set(struct a3700_spi *a3700_spi, + unsigned int pin_mode, bool receiving) +{ + u32 val; + + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + val &= ~(A3700_SPI_INST_PIN | A3700_SPI_ADDR_PIN); + val &= ~(A3700_SPI_DATA_PIN0 | A3700_SPI_DATA_PIN1); + + switch (pin_mode) { + case SPI_NBITS_SINGLE: + break; + case SPI_NBITS_DUAL: + val |= A3700_SPI_DATA_PIN0; + break; + case SPI_NBITS_QUAD: + val |= A3700_SPI_DATA_PIN1; + /* RX during address reception uses 4-pin */ + if (receiving) + val |= A3700_SPI_ADDR_PIN; + break; + default: + dev_err(&a3700_spi->master->dev, "wrong pin mode %u", pin_mode); + return -EINVAL; + } + + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); + + return 0; +} + +static void a3700_spi_fifo_mode_set(struct a3700_spi *a3700_spi, bool enable) +{ + u32 val; + + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + if (enable) + val |= A3700_SPI_FIFO_MODE; + else + val &= ~A3700_SPI_FIFO_MODE; + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); +} + +static void a3700_spi_mode_set(struct a3700_spi *a3700_spi, + unsigned int mode_bits) +{ + u32 val; + + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + + if (mode_bits & SPI_CPOL) + val |= A3700_SPI_CLK_POL; + else + val &= ~A3700_SPI_CLK_POL; + + if (mode_bits & SPI_CPHA) + val |= A3700_SPI_CLK_PHA; + else + val &= ~A3700_SPI_CLK_PHA; + + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); +} + +static void a3700_spi_clock_set(struct a3700_spi *a3700_spi, + unsigned int speed_hz) +{ + u32 val; + u32 prescale; + + prescale = DIV_ROUND_UP(clk_get_rate(a3700_spi->clk), speed_hz); + + /* For prescaler values over 15, we can only set it by steps of 2. + * Starting from A3700_SPI_CLK_EVEN_OFFS, we set values from 0 up to + * 30. We only use this range from 16 to 30. + */ + if (prescale > 15) + prescale = A3700_SPI_CLK_EVEN_OFFS + DIV_ROUND_UP(prescale, 2); + + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + val = val & ~A3700_SPI_CLK_PRESCALE_MASK; + + val = val | (prescale & A3700_SPI_CLK_PRESCALE_MASK); + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); + + if (prescale <= 2) { + val = spireg_read(a3700_spi, A3700_SPI_IF_TIME_REG); + val |= A3700_SPI_CLK_CAPT_EDGE; + spireg_write(a3700_spi, A3700_SPI_IF_TIME_REG, val); + } +} + +static void a3700_spi_bytelen_set(struct a3700_spi *a3700_spi, unsigned int len) +{ + u32 val; + + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + if (len == 4) + val |= A3700_SPI_BYTE_LEN; + else + val &= ~A3700_SPI_BYTE_LEN; + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); + + a3700_spi->byte_len = len; +} + +static int a3700_spi_fifo_flush(struct a3700_spi *a3700_spi) +{ + int timeout = A3700_SPI_TIMEOUT; + u32 val; + + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + val |= A3700_SPI_FIFO_FLUSH; + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); + + while (--timeout) { + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + if (!(val & A3700_SPI_FIFO_FLUSH)) + return 0; + udelay(1); + } + + return -ETIMEDOUT; +} + +static void a3700_spi_init(struct a3700_spi *a3700_spi) +{ + struct spi_master *master = a3700_spi->master; + u32 val; + int i; + + /* Reset SPI unit */ + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + val |= A3700_SPI_SRST; + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); + + udelay(A3700_SPI_TIMEOUT); + + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + val &= ~A3700_SPI_SRST; + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); + + /* Disable AUTO_CS and deactivate all chip-selects */ + a3700_spi_auto_cs_unset(a3700_spi); + for (i = 0; i < master->num_chipselect; i++) + a3700_spi_deactivate_cs(a3700_spi, i); + + /* Enable FIFO mode */ + a3700_spi_fifo_mode_set(a3700_spi, true); + + /* Set SPI mode */ + a3700_spi_mode_set(a3700_spi, master->mode_bits); + + /* Reset counters */ + spireg_write(a3700_spi, A3700_SPI_IF_HDR_CNT_REG, 0); + spireg_write(a3700_spi, A3700_SPI_IF_DIN_CNT_REG, 0); + + /* Mask the interrupts and clear cause bits */ + spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG, 0); + spireg_write(a3700_spi, A3700_SPI_INT_STAT_REG, ~0U); +} + +static irqreturn_t a3700_spi_interrupt(int irq, void *dev_id) +{ + struct spi_master *master = dev_id; + struct a3700_spi *a3700_spi; + u32 cause; + + a3700_spi = spi_master_get_devdata(master); + + /* Get interrupt causes */ + cause = spireg_read(a3700_spi, A3700_SPI_INT_STAT_REG); + + if (!cause || !(a3700_spi->wait_mask & cause)) + return IRQ_NONE; + + /* mask and acknowledge the SPI interrupts */ + spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG, 0); + spireg_write(a3700_spi, A3700_SPI_INT_STAT_REG, cause); + + /* Wake up the transfer */ + complete(&a3700_spi->done); + + return IRQ_HANDLED; +} + +static bool a3700_spi_wait_completion(struct spi_device *spi) +{ + struct a3700_spi *a3700_spi; + unsigned int timeout; + unsigned int ctrl_reg; + unsigned long timeout_jiffies; + + a3700_spi = spi_master_get_devdata(spi->master); + + /* SPI interrupt is edge-triggered, which means an interrupt will + * be generated only when detecting a specific status bit changed + * from '0' to '1'. So when we start waiting for a interrupt, we + * need to check status bit in control reg first, if it is already 1, + * then we do not need to wait for interrupt + */ + ctrl_reg = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG); + if (a3700_spi->wait_mask & ctrl_reg) + return true; + + reinit_completion(&a3700_spi->done); + + spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG, + a3700_spi->wait_mask); + + timeout_jiffies = msecs_to_jiffies(A3700_SPI_TIMEOUT); + timeout = wait_for_completion_timeout(&a3700_spi->done, + timeout_jiffies); + + a3700_spi->wait_mask = 0; + + if (timeout) + return true; + + /* there might be the case that right after we checked the + * status bits in this routine and before start to wait for + * interrupt by wait_for_completion_timeout, the interrupt + * happens, to avoid missing it we need to double check + * status bits in control reg, if it is already 1, then + * consider that we have the interrupt successfully and + * return true. + */ + ctrl_reg = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG); + if (a3700_spi->wait_mask & ctrl_reg) + return true; + + spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG, 0); + + /* Timeout was reached */ + return false; +} + +static bool a3700_spi_transfer_wait(struct spi_device *spi, + unsigned int bit_mask) +{ + struct a3700_spi *a3700_spi; + + a3700_spi = spi_master_get_devdata(spi->master); + a3700_spi->wait_mask = bit_mask; + + return a3700_spi_wait_completion(spi); +} + +static void a3700_spi_fifo_thres_set(struct a3700_spi *a3700_spi, + unsigned int bytes) +{ + u32 val; + + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + val &= ~(A3700_SPI_FIFO_THRS_MASK << A3700_SPI_RFIFO_THRS_BIT); + val |= (bytes - 1) << A3700_SPI_RFIFO_THRS_BIT; + val &= ~(A3700_SPI_FIFO_THRS_MASK << A3700_SPI_WFIFO_THRS_BIT); + val |= (7 - bytes) << A3700_SPI_WFIFO_THRS_BIT; + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); +} + +static void a3700_spi_transfer_setup(struct spi_device *spi, + struct spi_transfer *xfer) +{ + struct a3700_spi *a3700_spi; + + a3700_spi = spi_master_get_devdata(spi->master); + + a3700_spi_clock_set(a3700_spi, xfer->speed_hz); + + /* Use 4 bytes long transfers. Each transfer method has its way to deal + * with the remaining bytes for non 4-bytes aligned transfers. + */ + a3700_spi_bytelen_set(a3700_spi, 4); + + /* Initialize the working buffers */ + a3700_spi->tx_buf = xfer->tx_buf; + a3700_spi->rx_buf = xfer->rx_buf; + a3700_spi->buf_len = xfer->len; +} + +static void a3700_spi_set_cs(struct spi_device *spi, bool enable) +{ + struct a3700_spi *a3700_spi = spi_master_get_devdata(spi->master); + + if (!enable) + a3700_spi_activate_cs(a3700_spi, spi->chip_select); + else + a3700_spi_deactivate_cs(a3700_spi, spi->chip_select); +} + +static void a3700_spi_header_set(struct a3700_spi *a3700_spi) +{ + unsigned int addr_cnt; + u32 val = 0; + + /* Clear the header registers */ + spireg_write(a3700_spi, A3700_SPI_IF_INST_REG, 0); + spireg_write(a3700_spi, A3700_SPI_IF_ADDR_REG, 0); + spireg_write(a3700_spi, A3700_SPI_IF_RMODE_REG, 0); + spireg_write(a3700_spi, A3700_SPI_IF_HDR_CNT_REG, 0); + + /* Set header counters */ + if (a3700_spi->tx_buf) { + /* + * when tx data is not 4 bytes aligned, there will be unexpected + * bytes out of SPI output register, since it always shifts out + * as whole 4 bytes. This might cause incorrect transaction with + * some devices. To avoid that, use SPI header count feature to + * transfer up to 3 bytes of data first, and then make the rest + * of data 4-byte aligned. + */ + addr_cnt = a3700_spi->buf_len % 4; + if (addr_cnt) { + val = (addr_cnt & A3700_SPI_ADDR_CNT_MASK) + << A3700_SPI_ADDR_CNT_BIT; + spireg_write(a3700_spi, A3700_SPI_IF_HDR_CNT_REG, val); + + /* Update the buffer length to be transferred */ + a3700_spi->buf_len -= addr_cnt; + + /* transfer 1~3 bytes through address count */ + val = 0; + while (addr_cnt--) { + val = (val << 8) | a3700_spi->tx_buf[0]; + a3700_spi->tx_buf++; + } + spireg_write(a3700_spi, A3700_SPI_IF_ADDR_REG, val); + } + } +} + +static int a3700_is_wfifo_full(struct a3700_spi *a3700_spi) +{ + u32 val; + + val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG); + return (val & A3700_SPI_WFIFO_FULL); +} + +static int a3700_spi_fifo_write(struct a3700_spi *a3700_spi) +{ + u32 val; + + while (!a3700_is_wfifo_full(a3700_spi) && a3700_spi->buf_len) { + val = *(u32 *)a3700_spi->tx_buf; + spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG, cpu_to_le32(val)); + a3700_spi->buf_len -= 4; + a3700_spi->tx_buf += 4; + } + + return 0; +} + +static int a3700_is_rfifo_empty(struct a3700_spi *a3700_spi) +{ + u32 val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG); + + return (val & A3700_SPI_RFIFO_EMPTY); +} + +static int a3700_spi_fifo_read(struct a3700_spi *a3700_spi) +{ + u32 val; + + while (!a3700_is_rfifo_empty(a3700_spi) && a3700_spi->buf_len) { + val = spireg_read(a3700_spi, A3700_SPI_DATA_IN_REG); + if (a3700_spi->buf_len >= 4) { + val = le32_to_cpu(val); + memcpy(a3700_spi->rx_buf, &val, 4); + + a3700_spi->buf_len -= 4; + a3700_spi->rx_buf += 4; + } else { + /* + * When remain bytes is not larger than 4, we should + * avoid memory overwriting and just write the left rx + * buffer bytes. + */ + while (a3700_spi->buf_len) { + *a3700_spi->rx_buf = val & 0xff; + val >>= 8; + + a3700_spi->buf_len--; + a3700_spi->rx_buf++; + } + } + } + + return 0; +} + +static void a3700_spi_transfer_abort_fifo(struct a3700_spi *a3700_spi) +{ + int timeout = A3700_SPI_TIMEOUT; + u32 val; + + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + val |= A3700_SPI_XFER_STOP; + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); + + while (--timeout) { + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + if (!(val & A3700_SPI_XFER_START)) + break; + udelay(1); + } + + a3700_spi_fifo_flush(a3700_spi); + + val &= ~A3700_SPI_XFER_STOP; + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); +} + +static int a3700_spi_prepare_message(struct spi_master *master, + struct spi_message *message) +{ + struct a3700_spi *a3700_spi = spi_master_get_devdata(master); + struct spi_device *spi = message->spi; + int ret; + + ret = clk_enable(a3700_spi->clk); + if (ret) { + dev_err(&spi->dev, "failed to enable clk with error %d\n", ret); + return ret; + } + + /* Flush the FIFOs */ + ret = a3700_spi_fifo_flush(a3700_spi); + if (ret) + return ret; + + a3700_spi_mode_set(a3700_spi, spi->mode); + + return 0; +} + +static int a3700_spi_transfer_one_fifo(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *xfer) +{ + struct a3700_spi *a3700_spi = spi_master_get_devdata(master); + int ret = 0, timeout = A3700_SPI_TIMEOUT; + unsigned int nbits = 0, byte_len; + u32 val; + + /* Make sure we use FIFO mode */ + a3700_spi_fifo_mode_set(a3700_spi, true); + + /* Configure FIFO thresholds */ + byte_len = xfer->bits_per_word >> 3; + a3700_spi_fifo_thres_set(a3700_spi, byte_len); + + if (xfer->tx_buf) + nbits = xfer->tx_nbits; + else if (xfer->rx_buf) + nbits = xfer->rx_nbits; + + a3700_spi_pin_mode_set(a3700_spi, nbits, xfer->rx_buf ? true : false); + + /* Flush the FIFOs */ + a3700_spi_fifo_flush(a3700_spi); + + /* Transfer first bytes of data when buffer is not 4-byte aligned */ + a3700_spi_header_set(a3700_spi); + + if (xfer->rx_buf) { + /* Clear WFIFO, since it's last 2 bytes are shifted out during + * a read operation + */ + spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG, 0); + + /* Set read data length */ + spireg_write(a3700_spi, A3700_SPI_IF_DIN_CNT_REG, + a3700_spi->buf_len); + /* Start READ transfer */ + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + val &= ~A3700_SPI_RW_EN; + val |= A3700_SPI_XFER_START; + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); + } else if (xfer->tx_buf) { + /* Start Write transfer */ + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + val |= (A3700_SPI_XFER_START | A3700_SPI_RW_EN); + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); + + /* + * If there are data to be written to the SPI device, xmit_data + * flag is set true; otherwise the instruction in SPI_INSTR does + * not require data to be written to the SPI device, then + * xmit_data flag is set false. + */ + a3700_spi->xmit_data = (a3700_spi->buf_len != 0); + } + + while (a3700_spi->buf_len) { + if (a3700_spi->tx_buf) { + /* Wait wfifo ready */ + if (!a3700_spi_transfer_wait(spi, + A3700_SPI_WFIFO_RDY)) { + dev_err(&spi->dev, + "wait wfifo ready timed out\n"); + ret = -ETIMEDOUT; + goto error; + } + /* Fill up the wfifo */ + ret = a3700_spi_fifo_write(a3700_spi); + if (ret) + goto error; + } else if (a3700_spi->rx_buf) { + /* Wait rfifo ready */ + if (!a3700_spi_transfer_wait(spi, + A3700_SPI_RFIFO_RDY)) { + dev_err(&spi->dev, + "wait rfifo ready timed out\n"); + ret = -ETIMEDOUT; + goto error; + } + /* Drain out the rfifo */ + ret = a3700_spi_fifo_read(a3700_spi); + if (ret) + goto error; + } + } + + /* + * Stop a write transfer in fifo mode: + * - wait all the bytes in wfifo to be shifted out + * - set XFER_STOP bit + * - wait XFER_START bit clear + * - clear XFER_STOP bit + * Stop a read transfer in fifo mode: + * - the hardware is to reset the XFER_START bit + * after the number of bytes indicated in DIN_CNT + * register + * - just wait XFER_START bit clear + */ + if (a3700_spi->tx_buf) { + if (a3700_spi->xmit_data) { + /* + * If there are data written to the SPI device, wait + * until SPI_WFIFO_EMPTY is 1 to wait for all data to + * transfer out of write FIFO. + */ + if (!a3700_spi_transfer_wait(spi, + A3700_SPI_WFIFO_EMPTY)) { + dev_err(&spi->dev, "wait wfifo empty timed out\n"); + return -ETIMEDOUT; + } + } + + if (!a3700_spi_transfer_wait(spi, A3700_SPI_XFER_RDY)) { + dev_err(&spi->dev, "wait xfer ready timed out\n"); + return -ETIMEDOUT; + } + + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + val |= A3700_SPI_XFER_STOP; + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); + } + + while (--timeout) { + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); + if (!(val & A3700_SPI_XFER_START)) + break; + udelay(1); + } + + if (timeout == 0) { + dev_err(&spi->dev, "wait transfer start clear timed out\n"); + ret = -ETIMEDOUT; + goto error; + } + + val &= ~A3700_SPI_XFER_STOP; + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val); + goto out; + +error: + a3700_spi_transfer_abort_fifo(a3700_spi); +out: + spi_finalize_current_transfer(master); + + return ret; +} + +static int a3700_spi_transfer_one_full_duplex(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *xfer) +{ + struct a3700_spi *a3700_spi = spi_master_get_devdata(master); + u32 val; + + /* Disable FIFO mode */ + a3700_spi_fifo_mode_set(a3700_spi, false); + + while (a3700_spi->buf_len) { + + /* When we have less than 4 bytes to transfer, switch to 1 byte + * mode. This is reset after each transfer + */ + if (a3700_spi->buf_len < 4) + a3700_spi_bytelen_set(a3700_spi, 1); + + if (a3700_spi->byte_len == 1) + val = *a3700_spi->tx_buf; + else + val = *(u32 *)a3700_spi->tx_buf; + + spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG, val); + + /* Wait for all the data to be shifted in / out */ + while (!(spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG) & + A3700_SPI_XFER_DONE)) + cpu_relax(); + + val = spireg_read(a3700_spi, A3700_SPI_DATA_IN_REG); + + memcpy(a3700_spi->rx_buf, &val, a3700_spi->byte_len); + + a3700_spi->buf_len -= a3700_spi->byte_len; + a3700_spi->tx_buf += a3700_spi->byte_len; + a3700_spi->rx_buf += a3700_spi->byte_len; + + } + + spi_finalize_current_transfer(master); + + return 0; +} + +static int a3700_spi_transfer_one(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *xfer) +{ + a3700_spi_transfer_setup(spi, xfer); + + if (xfer->tx_buf && xfer->rx_buf) + return a3700_spi_transfer_one_full_duplex(master, spi, xfer); + + return a3700_spi_transfer_one_fifo(master, spi, xfer); +} + +static int a3700_spi_unprepare_message(struct spi_master *master, + struct spi_message *message) +{ + struct a3700_spi *a3700_spi = spi_master_get_devdata(master); + + clk_disable(a3700_spi->clk); + + return 0; +} + +static const struct of_device_id a3700_spi_dt_ids[] = { + { .compatible = "marvell,armada-3700-spi", .data = NULL }, + {}, +}; + +MODULE_DEVICE_TABLE(of, a3700_spi_dt_ids); + +static int a3700_spi_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *of_node = dev->of_node; + struct spi_master *master; + struct a3700_spi *spi; + u32 num_cs = 0; + int irq, ret = 0; + + master = spi_alloc_master(dev, sizeof(*spi)); + if (!master) { + dev_err(dev, "master allocation failed\n"); + ret = -ENOMEM; + goto out; + } + + if (of_property_read_u32(of_node, "num-cs", &num_cs)) { + dev_err(dev, "could not find num-cs\n"); + ret = -ENXIO; + goto error; + } + + master->bus_num = pdev->id; + master->dev.of_node = of_node; + master->mode_bits = SPI_MODE_3; + master->num_chipselect = num_cs; + master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(32); + master->prepare_message = a3700_spi_prepare_message; + master->transfer_one = a3700_spi_transfer_one; + master->unprepare_message = a3700_spi_unprepare_message; + master->set_cs = a3700_spi_set_cs; + master->mode_bits |= (SPI_RX_DUAL | SPI_TX_DUAL | + SPI_RX_QUAD | SPI_TX_QUAD); + + platform_set_drvdata(pdev, master); + + spi = spi_master_get_devdata(master); + + spi->master = master; + + spi->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(spi->base)) { + ret = PTR_ERR(spi->base); + goto error; + } + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + ret = -ENXIO; + goto error; + } + spi->irq = irq; + + init_completion(&spi->done); + + spi->clk = devm_clk_get(dev, NULL); + if (IS_ERR(spi->clk)) { + dev_err(dev, "could not find clk: %ld\n", PTR_ERR(spi->clk)); + goto error; + } + + ret = clk_prepare(spi->clk); + if (ret) { + dev_err(dev, "could not prepare clk: %d\n", ret); + goto error; + } + + master->max_speed_hz = min_t(unsigned long, A3700_SPI_MAX_SPEED_HZ, + clk_get_rate(spi->clk)); + master->min_speed_hz = DIV_ROUND_UP(clk_get_rate(spi->clk), + A3700_SPI_MAX_PRESCALE); + + a3700_spi_init(spi); + + ret = devm_request_irq(dev, spi->irq, a3700_spi_interrupt, 0, + dev_name(dev), master); + if (ret) { + dev_err(dev, "could not request IRQ: %d\n", ret); + goto error_clk; + } + + ret = devm_spi_register_master(dev, master); + if (ret) { + dev_err(dev, "Failed to register master\n"); + goto error_clk; + } + + return 0; + +error_clk: + clk_unprepare(spi->clk); +error: + spi_master_put(master); +out: + return ret; +} + +static int a3700_spi_remove(struct platform_device *pdev) +{ + struct spi_master *master = platform_get_drvdata(pdev); + struct a3700_spi *spi = spi_master_get_devdata(master); + + clk_unprepare(spi->clk); + + return 0; +} + +static struct platform_driver a3700_spi_driver = { + .driver = { + .name = DRIVER_NAME, + .of_match_table = of_match_ptr(a3700_spi_dt_ids), + }, + .probe = a3700_spi_probe, + .remove = a3700_spi_remove, +}; + +module_platform_driver(a3700_spi_driver); + +MODULE_DESCRIPTION("Armada-3700 SPI driver"); +MODULE_AUTHOR("Wilson Ding <dingwei@marvell.com>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:" DRIVER_NAME); |