u-boot/drivers/spi/mvebu_a3700_spi.c

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/*
* Copyright (C) 2015 Marvell International Ltd.
*
* Copyright (C) 2016 Stefan Roese <sr@denx.de>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <malloc.h>
#include <spi.h>
#include <wait_bit.h>
#include <asm/io.h>
DECLARE_GLOBAL_DATA_PTR;
#define MVEBU_SPI_A3700_XFER_RDY BIT(1)
#define MVEBU_SPI_A3700_FIFO_FLUSH BIT(9)
#define MVEBU_SPI_A3700_BYTE_LEN BIT(5)
#define MVEBU_SPI_A3700_CLK_PHA BIT(6)
#define MVEBU_SPI_A3700_CLK_POL BIT(7)
#define MVEBU_SPI_A3700_FIFO_EN BIT(17)
#define MVEBU_SPI_A3700_SPI_EN_0 BIT(16)
#define MVEBU_SPI_A3700_CLK_PRESCALE_BIT 0
#define MVEBU_SPI_A3700_CLK_PRESCALE_MASK \
(0x1f << MVEBU_SPI_A3700_CLK_PRESCALE_BIT)
/* SPI registers */
struct spi_reg {
u32 ctrl; /* 0x10600 */
u32 cfg; /* 0x10604 */
u32 dout; /* 0x10608 */
u32 din; /* 0x1060c */
};
struct mvebu_spi_platdata {
struct spi_reg *spireg;
unsigned int frequency;
unsigned int clock;
};
static void spi_cs_activate(struct spi_reg *reg, int cs)
{
setbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
}
static void spi_cs_deactivate(struct spi_reg *reg, int cs)
{
clrbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
}
/**
* spi_legacy_shift_byte() - triggers the real SPI transfer
* @bytelen: Indicate how many bytes to transfer.
* @dout: Buffer address of what to send.
* @din: Buffer address of where to receive.
*
* This function triggers the real SPI transfer in legacy mode. It
* will shift out char buffer from @dout, and shift in char buffer to
* @din, if necessary.
*
* This function assumes that only one byte is shifted at one time.
* However, it is not its responisbility to set the transfer type to
* one-byte. Also, it does not guarantee that it will work if transfer
* type becomes two-byte. See spi_set_legacy() for details.
*
* In legacy mode, simply write to the SPI_DOUT register will trigger
* the transfer.
*
* If @dout == NULL, which means no actual data needs to be sent out,
* then the function will shift out 0x00 in order to shift in data.
* The XFER_RDY flag is checked every time before accessing SPI_DOUT
* and SPI_DIN register.
*
* The number of transfers to be triggerred is decided by @bytelen.
*
* Return: 0 - cool
* -ETIMEDOUT - XFER_RDY flag timeout
*/
static int spi_legacy_shift_byte(struct spi_reg *reg, unsigned int bytelen,
const void *dout, void *din)
{
const u8 *dout_8;
u8 *din_8;
int ret;
/* Use 0x00 as dummy dout */
const u8 dummy_dout = 0x0;
u32 pending_dout = 0x0;
/* dout_8: pointer of current dout */
dout_8 = dout;
/* din_8: pointer of current din */
din_8 = din;
while (bytelen) {
ret = wait_for_bit(__func__, &reg->ctrl,
MVEBU_SPI_A3700_XFER_RDY, true, 100, false);
if (ret)
return ret;
if (dout)
pending_dout = (u32)*dout_8;
else
pending_dout = (u32)dummy_dout;
/* Trigger the xfer */
writel(pending_dout, &reg->dout);
if (din) {
ret = wait_for_bit(__func__, &reg->ctrl,
MVEBU_SPI_A3700_XFER_RDY,
true, 100, false);
if (ret)
return ret;
/* Read what is transferred in */
*din_8 = (u8)readl(&reg->din);
}
/* Don't increment the current pointer if NULL */
if (dout)
dout_8++;
if (din)
din_8++;
bytelen--;
}
return 0;
}
static int mvebu_spi_xfer(struct udevice *dev, unsigned int bitlen,
const void *dout, void *din, unsigned long flags)
{
struct udevice *bus = dev->parent;
struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
struct spi_reg *reg = plat->spireg;
unsigned int bytelen;
int ret;
bytelen = bitlen / 8;
if (dout && din)
debug("This is a duplex transfer.\n");
/* Activate CS */
if (flags & SPI_XFER_BEGIN) {
debug("SPI: activate cs.\n");
spi_cs_activate(reg, spi_chip_select(dev));
}
/* Send and/or receive */
if (dout || din) {
ret = spi_legacy_shift_byte(reg, bytelen, dout, din);
if (ret)
return ret;
}
/* Deactivate CS */
if (flags & SPI_XFER_END) {
ret = wait_for_bit(__func__, &reg->ctrl,
MVEBU_SPI_A3700_XFER_RDY, true, 100, false);
if (ret)
return ret;
debug("SPI: deactivate cs.\n");
spi_cs_deactivate(reg, spi_chip_select(dev));
}
return 0;
}
static int mvebu_spi_set_speed(struct udevice *bus, uint hz)
{
struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
struct spi_reg *reg = plat->spireg;
u32 data;
data = readl(&reg->cfg);
/* Set Prescaler */
data &= ~MVEBU_SPI_A3700_CLK_PRESCALE_MASK;
/* Calculate Prescaler = (spi_input_freq / spi_max_freq) */
if (hz > plat->frequency)
hz = plat->frequency;
data |= plat->clock / hz;
writel(data, &reg->cfg);
return 0;
}
static int mvebu_spi_set_mode(struct udevice *bus, uint mode)
{
struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
struct spi_reg *reg = plat->spireg;
/*
* Set SPI polarity
* 0: Serial interface clock is low when inactive
* 1: Serial interface clock is high when inactive
*/
if (mode & SPI_CPOL)
setbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_POL);
else
clrbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_POL);
if (mode & SPI_CPHA)
setbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_PHA);
else
clrbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_PHA);
return 0;
}
static int mvebu_spi_probe(struct udevice *bus)
{
struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
struct spi_reg *reg = plat->spireg;
u32 data;
int ret;
/*
* Settings SPI controller to be working in legacy mode, which
* means use only DO pin (I/O 1) for Data Out, and DI pin (I/O 0)
* for Data In.
*/
/* Flush read/write FIFO */
data = readl(&reg->cfg);
writel(data | MVEBU_SPI_A3700_FIFO_FLUSH, &reg->cfg);
ret = wait_for_bit(__func__, &reg->cfg, MVEBU_SPI_A3700_FIFO_FLUSH,
false, 1000, false);
if (ret)
return ret;
/* Disable FIFO mode */
data &= ~MVEBU_SPI_A3700_FIFO_EN;
/* Always shift 1 byte at a time */
data &= ~MVEBU_SPI_A3700_BYTE_LEN;
writel(data, &reg->cfg);
return 0;
}
static int mvebu_spi_ofdata_to_platdata(struct udevice *bus)
{
struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
plat->spireg = (struct spi_reg *)dev_get_addr(bus);
/*
* FIXME
* Right now, mvebu does not have a clock infrastructure in U-Boot
* which should be used to query the input clock to the SPI
* controller. Once this clock driver is integrated into U-Boot
* it should be used to read the input clock and the DT property
* can be removed.
*/
plat->clock = fdtdec_get_int(gd->fdt_blob, dev_of_offset(bus),
"clock-frequency", 160000);
plat->frequency = fdtdec_get_int(gd->fdt_blob, dev_of_offset(bus),
"spi-max-frequency", 40000);
return 0;
}
static const struct dm_spi_ops mvebu_spi_ops = {
.xfer = mvebu_spi_xfer,
.set_speed = mvebu_spi_set_speed,
.set_mode = mvebu_spi_set_mode,
/*
* cs_info is not needed, since we require all chip selects to be
* in the device tree explicitly
*/
};
static const struct udevice_id mvebu_spi_ids[] = {
{ .compatible = "marvell,armada-3700-spi" },
{ }
};
U_BOOT_DRIVER(mvebu_spi) = {
.name = "mvebu_spi",
.id = UCLASS_SPI,
.of_match = mvebu_spi_ids,
.ops = &mvebu_spi_ops,
.ofdata_to_platdata = mvebu_spi_ofdata_to_platdata,
.platdata_auto_alloc_size = sizeof(struct mvebu_spi_platdata),
.probe = mvebu_spi_probe,
};