u-boot/drivers/spi/atmel_spi.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2007 Atmel Corporation
*/
#include <common.h>
#include <clk.h>
#include <dm.h>
#include <fdtdec.h>
#include <spi.h>
#include <malloc.h>
#include <wait_bit.h>
#include <asm/io.h>
#include <asm/arch/clk.h>
#include <asm/arch/hardware.h>
#include <asm/arch/at91_spi.h>
#if CONFIG_IS_ENABLED(DM_GPIO)
#include <asm/gpio.h>
#endif
#include <linux/bitops.h>
#include <linux/printk.h>
/*
* Register definitions for the Atmel AT32/AT91 SPI Controller
*/
/* Register offsets */
#define ATMEL_SPI_CR 0x0000
#define ATMEL_SPI_MR 0x0004
#define ATMEL_SPI_RDR 0x0008
#define ATMEL_SPI_TDR 0x000c
#define ATMEL_SPI_SR 0x0010
#define ATMEL_SPI_IER 0x0014
#define ATMEL_SPI_IDR 0x0018
#define ATMEL_SPI_IMR 0x001c
#define ATMEL_SPI_CSR(x) (0x0030 + 4 * (x))
#define ATMEL_SPI_VERSION 0x00fc
/* Bits in CR */
#define ATMEL_SPI_CR_SPIEN BIT(0)
#define ATMEL_SPI_CR_SPIDIS BIT(1)
#define ATMEL_SPI_CR_SWRST BIT(7)
#define ATMEL_SPI_CR_LASTXFER BIT(24)
/* Bits in MR */
#define ATMEL_SPI_MR_MSTR BIT(0)
#define ATMEL_SPI_MR_PS BIT(1)
#define ATMEL_SPI_MR_PCSDEC BIT(2)
#define ATMEL_SPI_MR_FDIV BIT(3)
#define ATMEL_SPI_MR_MODFDIS BIT(4)
#define ATMEL_SPI_MR_WDRBT BIT(5)
#define ATMEL_SPI_MR_LLB BIT(7)
#define ATMEL_SPI_MR_PCS(x) (((x) & 15) << 16)
#define ATMEL_SPI_MR_DLYBCS(x) ((x) << 24)
/* Bits in RDR */
#define ATMEL_SPI_RDR_RD(x) (x)
#define ATMEL_SPI_RDR_PCS(x) ((x) << 16)
/* Bits in TDR */
#define ATMEL_SPI_TDR_TD(x) (x)
#define ATMEL_SPI_TDR_PCS(x) ((x) << 16)
#define ATMEL_SPI_TDR_LASTXFER BIT(24)
/* Bits in SR/IER/IDR/IMR */
#define ATMEL_SPI_SR_RDRF BIT(0)
#define ATMEL_SPI_SR_TDRE BIT(1)
#define ATMEL_SPI_SR_MODF BIT(2)
#define ATMEL_SPI_SR_OVRES BIT(3)
#define ATMEL_SPI_SR_ENDRX BIT(4)
#define ATMEL_SPI_SR_ENDTX BIT(5)
#define ATMEL_SPI_SR_RXBUFF BIT(6)
#define ATMEL_SPI_SR_TXBUFE BIT(7)
#define ATMEL_SPI_SR_NSSR BIT(8)
#define ATMEL_SPI_SR_TXEMPTY BIT(9)
#define ATMEL_SPI_SR_SPIENS BIT(16)
/* Bits in CSRx */
#define ATMEL_SPI_CSRx_CPOL BIT(0)
#define ATMEL_SPI_CSRx_NCPHA BIT(1)
#define ATMEL_SPI_CSRx_CSAAT BIT(3)
#define ATMEL_SPI_CSRx_BITS(x) ((x) << 4)
#define ATMEL_SPI_CSRx_SCBR(x) ((x) << 8)
#define ATMEL_SPI_CSRx_SCBR_MAX GENMASK(7, 0)
#define ATMEL_SPI_CSRx_DLYBS(x) ((x) << 16)
#define ATMEL_SPI_CSRx_DLYBCT(x) ((x) << 24)
/* Bits in VERSION */
#define ATMEL_SPI_VERSION_REV(x) ((x) & 0xfff)
#define ATMEL_SPI_VERSION_MFN(x) ((x) << 16)
/* Constants for CSRx:BITS */
#define ATMEL_SPI_BITS_8 0
#define ATMEL_SPI_BITS_9 1
#define ATMEL_SPI_BITS_10 2
#define ATMEL_SPI_BITS_11 3
#define ATMEL_SPI_BITS_12 4
#define ATMEL_SPI_BITS_13 5
#define ATMEL_SPI_BITS_14 6
#define ATMEL_SPI_BITS_15 7
#define ATMEL_SPI_BITS_16 8
#define MAX_CS_COUNT 4
/* Register access macros */
#define spi_readl(as, reg) \
readl(as->regs + ATMEL_SPI_##reg)
#define spi_writel(as, reg, value) \
writel(value, as->regs + ATMEL_SPI_##reg)
struct atmel_spi_plat {
struct at91_spi *regs;
};
struct atmel_spi_priv {
unsigned int freq; /* Default frequency */
unsigned int mode;
ulong bus_clk_rate;
#if CONFIG_IS_ENABLED(DM_GPIO)
struct gpio_desc cs_gpios[MAX_CS_COUNT];
#endif
};
static int atmel_spi_claim_bus(struct udevice *dev)
{
struct udevice *bus = dev_get_parent(dev);
struct atmel_spi_plat *bus_plat = dev_get_plat(bus);
struct atmel_spi_priv *priv = dev_get_priv(bus);
struct dm_spi_slave_plat *slave_plat = dev_get_parent_plat(dev);
struct at91_spi *reg_base = bus_plat->regs;
u32 cs = slave_plat->cs;
u32 freq = priv->freq;
u32 scbr, csrx, mode;
scbr = (priv->bus_clk_rate + freq - 1) / freq;
if (scbr > ATMEL_SPI_CSRx_SCBR_MAX)
return -EINVAL;
if (scbr < 1)
scbr = 1;
csrx = ATMEL_SPI_CSRx_SCBR(scbr);
csrx |= ATMEL_SPI_CSRx_BITS(ATMEL_SPI_BITS_8);
if (!(priv->mode & SPI_CPHA))
csrx |= ATMEL_SPI_CSRx_NCPHA;
if (priv->mode & SPI_CPOL)
csrx |= ATMEL_SPI_CSRx_CPOL;
writel(csrx, &reg_base->csr[cs]);
mode = ATMEL_SPI_MR_MSTR |
ATMEL_SPI_MR_MODFDIS |
ATMEL_SPI_MR_WDRBT |
ATMEL_SPI_MR_PCS(~(1 << cs));
writel(mode, &reg_base->mr);
writel(ATMEL_SPI_CR_SPIEN, &reg_base->cr);
return 0;
}
static int atmel_spi_release_bus(struct udevice *dev)
{
struct udevice *bus = dev_get_parent(dev);
struct atmel_spi_plat *bus_plat = dev_get_plat(bus);
writel(ATMEL_SPI_CR_SPIDIS, &bus_plat->regs->cr);
return 0;
}
static void atmel_spi_cs_activate(struct udevice *dev)
{
#if CONFIG_IS_ENABLED(DM_GPIO)
struct udevice *bus = dev_get_parent(dev);
struct atmel_spi_priv *priv = dev_get_priv(bus);
struct dm_spi_slave_plat *slave_plat = dev_get_parent_plat(dev);
u32 cs = slave_plat->cs;
if (!dm_gpio_is_valid(&priv->cs_gpios[cs]))
return;
dm_gpio_set_value(&priv->cs_gpios[cs], 0);
#endif
}
static void atmel_spi_cs_deactivate(struct udevice *dev)
{
#if CONFIG_IS_ENABLED(DM_GPIO)
struct udevice *bus = dev_get_parent(dev);
struct atmel_spi_priv *priv = dev_get_priv(bus);
struct dm_spi_slave_plat *slave_plat = dev_get_parent_plat(dev);
u32 cs = slave_plat->cs;
if (!dm_gpio_is_valid(&priv->cs_gpios[cs]))
return;
dm_gpio_set_value(&priv->cs_gpios[cs], 1);
#endif
}
static int atmel_spi_xfer(struct udevice *dev, unsigned int bitlen,
const void *dout, void *din, unsigned long flags)
{
struct udevice *bus = dev_get_parent(dev);
struct atmel_spi_plat *bus_plat = dev_get_plat(bus);
struct at91_spi *reg_base = bus_plat->regs;
u32 len_tx, len_rx, len;
u32 status;
const u8 *txp = dout;
u8 *rxp = din;
u8 value;
if (bitlen == 0)
goto out;
/*
* The controller can do non-multiple-of-8 bit
* transfers, but this driver currently doesn't support it.
*
* It's also not clear how such transfers are supposed to be
* represented as a stream of bytes...this is a limitation of
* the current SPI interface.
*/
if (bitlen % 8) {
/* Errors always terminate an ongoing transfer */
flags |= SPI_XFER_END;
goto out;
}
len = bitlen / 8;
/*
* The controller can do automatic CS control, but it is
* somewhat quirky, and it doesn't really buy us much anyway
* in the context of U-Boot.
*/
if (flags & SPI_XFER_BEGIN) {
atmel_spi_cs_activate(dev);
/*
* sometimes the RDR is not empty when we get here,
* in theory that should not happen, but it DOES happen.
* Read it here to be on the safe side.
* That also clears the OVRES flag. Required if the
* following loop exits due to OVRES!
*/
readl(&reg_base->rdr);
}
for (len_tx = 0, len_rx = 0; len_rx < len; ) {
status = readl(&reg_base->sr);
if (status & ATMEL_SPI_SR_OVRES)
return -1;
if ((len_tx < len) && (status & ATMEL_SPI_SR_TDRE)) {
if (txp)
value = *txp++;
else
value = 0;
writel(value, &reg_base->tdr);
len_tx++;
}
if (status & ATMEL_SPI_SR_RDRF) {
value = readl(&reg_base->rdr);
if (rxp)
*rxp++ = value;
len_rx++;
}
}
out:
if (flags & SPI_XFER_END) {
/*
* Wait until the transfer is completely done before
* we deactivate CS.
*/
wait_for_bit_le32(&reg_base->sr,
ATMEL_SPI_SR_TXEMPTY, true, 1000, false);
atmel_spi_cs_deactivate(dev);
}
return 0;
}
static int atmel_spi_set_speed(struct udevice *bus, uint speed)
{
struct atmel_spi_priv *priv = dev_get_priv(bus);
priv->freq = speed;
return 0;
}
static int atmel_spi_set_mode(struct udevice *bus, uint mode)
{
struct atmel_spi_priv *priv = dev_get_priv(bus);
priv->mode = mode;
return 0;
}
static const struct dm_spi_ops atmel_spi_ops = {
.claim_bus = atmel_spi_claim_bus,
.release_bus = atmel_spi_release_bus,
.xfer = atmel_spi_xfer,
.set_speed = atmel_spi_set_speed,
.set_mode = atmel_spi_set_mode,
/*
* cs_info is not needed, since we require all chip selects to be
* in the device tree explicitly
*/
};
static int atmel_spi_enable_clk(struct udevice *bus)
{
struct atmel_spi_priv *priv = dev_get_priv(bus);
struct clk clk;
ulong clk_rate;
int ret;
ret = clk_get_by_index(bus, 0, &clk);
if (ret)
return -EINVAL;
ret = clk_enable(&clk);
if (ret)
return ret;
clk_rate = clk_get_rate(&clk);
if (!clk_rate)
return -EINVAL;
priv->bus_clk_rate = clk_rate;
clk_free(&clk);
return 0;
}
static int atmel_spi_probe(struct udevice *bus)
{
struct atmel_spi_plat *bus_plat = dev_get_plat(bus);
int ret;
ret = atmel_spi_enable_clk(bus);
if (ret)
return ret;
bus_plat->regs = dev_read_addr_ptr(bus);
#if CONFIG_IS_ENABLED(DM_GPIO)
struct atmel_spi_priv *priv = dev_get_priv(bus);
int i;
ret = gpio_request_list_by_name(bus, "cs-gpios", priv->cs_gpios,
ARRAY_SIZE(priv->cs_gpios), 0);
if (ret < 0) {
pr_err("Can't get %s gpios! Error: %d", bus->name, ret);
return ret;
}
for(i = 0; i < ARRAY_SIZE(priv->cs_gpios); i++) {
if (!dm_gpio_is_valid(&priv->cs_gpios[i]))
continue;
dm_gpio_set_dir_flags(&priv->cs_gpios[i],
GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
}
#endif
writel(ATMEL_SPI_CR_SWRST, &bus_plat->regs->cr);
return 0;
}
static const struct udevice_id atmel_spi_ids[] = {
{ .compatible = "atmel,at91rm9200-spi" },
{ }
};
U_BOOT_DRIVER(atmel_spi) = {
.name = "atmel_spi",
.id = UCLASS_SPI,
.of_match = atmel_spi_ids,
.ops = &atmel_spi_ops,
.plat_auto = sizeof(struct atmel_spi_plat),
.priv_auto = sizeof(struct atmel_spi_priv),
.probe = atmel_spi_probe,
};