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linux-sg2042/drivers/spi/spi-armada-3700.c

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// 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 int a3700_spi_init(struct a3700_spi *a3700_spi)
{
struct spi_master *master = a3700_spi->master;
u32 val;
int i, ret = 0;
/* 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);
return ret;
}
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, 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) {
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);
memset(spi, 0, sizeof(struct a3700_spi));
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);
ret = a3700_spi_init(spi);
if (ret)
goto error_clk;
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_disable_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);
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