// SPDX-License-Identifier: GPL-2.0
// spi-uniphier.c - Socionext UniPhier SPI controller driver
// Copyright 2012 Panasonic Corporation
// Copyright 2016-2018 Socionext Inc.
#include <linux/kernel.h>
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <asm/unaligned.h>
#define SSI_TIMEOUT_MS 2000
#define SSI_MAX_CLK_DIVIDER 254
#define SSI_MIN_CLK_DIVIDER 4
struct uniphier_spi_priv {
void __iomem *base;
struct clk *clk;
struct spi_master *master;
struct completion xfer_done;
int error;
unsigned int tx_bytes;
unsigned int rx_bytes;
const u8 *tx_buf;
u8 *rx_buf;
bool is_save_param;
u8 bits_per_word;
u16 mode;
u32 speed_hz;
};
#define SSI_CTL 0x00
#define SSI_CTL_EN BIT(0)
#define SSI_CKS 0x04
#define SSI_CKS_CKRAT_MASK GENMASK(7, 0)
#define SSI_CKS_CKPHS BIT(14)
#define SSI_CKS_CKINIT BIT(13)
#define SSI_CKS_CKDLY BIT(12)
#define SSI_TXWDS 0x08
#define SSI_TXWDS_WDLEN_MASK GENMASK(13, 8)
#define SSI_TXWDS_TDTF_MASK GENMASK(7, 6)
#define SSI_TXWDS_DTLEN_MASK GENMASK(5, 0)
#define SSI_RXWDS 0x0c
#define SSI_RXWDS_DTLEN_MASK GENMASK(5, 0)
#define SSI_FPS 0x10
#define SSI_FPS_FSPOL BIT(15)
#define SSI_FPS_FSTRT BIT(14)
#define SSI_SR 0x14
#define SSI_SR_RNE BIT(0)
#define SSI_IE 0x18
#define SSI_IE_RCIE BIT(3)
#define SSI_IE_RORIE BIT(0)
#define SSI_IS 0x1c
#define SSI_IS_RXRS BIT(9)
#define SSI_IS_RCID BIT(3)
#define SSI_IS_RORID BIT(0)
#define SSI_IC 0x1c
#define SSI_IC_TCIC BIT(4)
#define SSI_IC_RCIC BIT(3)
#define SSI_IC_RORIC BIT(0)
#define SSI_FC 0x20
#define SSI_FC_TXFFL BIT(12)
#define SSI_FC_TXFTH_MASK GENMASK(11, 8)
#define SSI_FC_RXFFL BIT(4)
#define SSI_FC_RXFTH_MASK GENMASK(3, 0)
#define SSI_TXDR 0x24
#define SSI_RXDR 0x24
#define SSI_FIFO_DEPTH 8U
static inline unsigned int bytes_per_word(unsigned int bits)
{
return bits <= 8 ? 1 : (bits <= 16 ? 2 : 4);
}
static inline void uniphier_spi_irq_enable(struct spi_device *spi, u32 mask)
{
struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
u32 val;
val = readl(priv->base + SSI_IE);
val |= mask;
writel(val, priv->base + SSI_IE);
}
static inline void uniphier_spi_irq_disable(struct spi_device *spi, u32 mask)
{
struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
u32 val;
val = readl(priv->base + SSI_IE);
val &= ~mask;
writel(val, priv->base + SSI_IE);
}
static void uniphier_spi_set_mode(struct spi_device *spi)
{
struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
u32 val1, val2;
/*
* clock setting
* CKPHS capture timing. 0:rising edge, 1:falling edge
* CKINIT clock initial level. 0:low, 1:high
* CKDLY clock delay. 0:no delay, 1:delay depending on FSTRT
* (FSTRT=0: 1 clock, FSTRT=1: 0.5 clock)
*
* frame setting
* FSPOL frame signal porarity. 0: low, 1: high
* FSTRT start frame timing
* 0: rising edge of clock, 1: falling edge of clock
*/
switch (spi->mode & (SPI_CPOL | SPI_CPHA)) {
case SPI_MODE_0:
/* CKPHS=1, CKINIT=0, CKDLY=1, FSTRT=0 */
val1 = SSI_CKS_CKPHS | SSI_CKS_CKDLY;
val2 = 0;
break;
case SPI_MODE_1:
/* CKPHS=0, CKINIT=0, CKDLY=0, FSTRT=1 */
val1 = 0;
val2 = SSI_FPS_FSTRT;
break;
case SPI_MODE_2:
/* CKPHS=0, CKINIT=1, CKDLY=1, FSTRT=1 */
val1 = SSI_CKS_CKINIT | SSI_CKS_CKDLY;
val2 = SSI_FPS_FSTRT;
break;
case SPI_MODE_3:
/* CKPHS=1, CKINIT=1, CKDLY=0, FSTRT=0 */
val1 = SSI_CKS_CKPHS | SSI_CKS_CKINIT;
val2 = 0;
break;
}
if (!(spi->mode & SPI_CS_HIGH))
val2 |= SSI_FPS_FSPOL;
writel(val1, priv->base + SSI_CKS);
writel(val2, priv->base + SSI_FPS);
val1 = 0;
if (spi->mode & SPI_LSB_FIRST)
val1 |= FIELD_PREP(SSI_TXWDS_TDTF_MASK, 1);
writel(val1, priv->base + SSI_TXWDS);
writel(val1, priv->base + SSI_RXWDS);
}
static void uniphier_spi_set_transfer_size(struct spi_device *spi, int size)
{
struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
u32 val;
val = readl(priv->base + SSI_TXWDS);
val &= ~(SSI_TXWDS_WDLEN_MASK | SSI_TXWDS_DTLEN_MASK);
val |= FIELD_PREP(SSI_TXWDS_WDLEN_MASK, size);
val |= FIELD_PREP(SSI_TXWDS_DTLEN_MASK, size);
writel(val, priv->base + SSI_TXWDS);
val = readl(priv->base + SSI_RXWDS);
val &= ~SSI_RXWDS_DTLEN_MASK;
val |= FIELD_PREP(SSI_RXWDS_DTLEN_MASK, size);
writel(val, priv->base + SSI_RXWDS);
}
static void uniphier_spi_set_baudrate(struct spi_device *spi,
unsigned int speed)
{
struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
u32 val, ckdiv;
/*
* the supported rates are even numbers from 4 to 254. (4,6,8...254)
* round up as we look for equal or less speed
*/
ckdiv = DIV_ROUND_UP(clk_get_rate(priv->clk), speed);
ckdiv = round_up(ckdiv, 2);
val = readl(priv->base + SSI_CKS);
val &= ~SSI_CKS_CKRAT_MASK;
val |= ckdiv & SSI_CKS_CKRAT_MASK;
writel(val, priv->base + SSI_CKS);
}
static void uniphier_spi_setup_transfer(struct spi_device *spi,
struct spi_transfer *t)
{
struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
u32 val;
priv->error = 0;
priv->tx_buf = t->tx_buf;
priv->rx_buf = t->rx_buf;
priv->tx_bytes = priv->rx_bytes = t->len;
if (!priv->is_save_param || priv->mode != spi->mode) {
uniphier_spi_set_mode(spi);
priv->mode = spi->mode;
}
if (!priv->is_save_param || priv->bits_per_word != t->bits_per_word) {
uniphier_spi_set_transfer_size(spi, t->bits_per_word);
priv->bits_per_word = t->bits_per_word;
}
if (!priv->is_save_param || priv->speed_hz != t->speed_hz) {
uniphier_spi_set_baudrate(spi, t->speed_hz);
priv->speed_hz = t->speed_hz;
}
if (!priv->is_save_param)
priv->is_save_param = true;
/* reset FIFOs */
val = SSI_FC_TXFFL | SSI_FC_RXFFL;
writel(val, priv->base + SSI_FC);
}
static void uniphier_spi_send(struct uniphier_spi_priv *priv)
{
int wsize;
u32 val = 0;
wsize = min(bytes_per_word(priv->bits_per_word), priv->tx_bytes);
priv->tx_bytes -= wsize;
if (priv->tx_buf) {
switch (wsize) {
case 1:
val = *priv->tx_buf;
break;
case 2:
val = get_unaligned_le16(priv->tx_buf);
break;
case 4:
val = get_unaligned_le32(priv->tx_buf);
break;
}
priv->tx_buf += wsize;
}
writel(val, priv->base + SSI_TXDR);
}
static void uniphier_spi_recv(struct uniphier_spi_priv *priv)
{
int rsize;
u32 val;
rsize = min(bytes_per_word(priv->bits_per_word), priv->rx_bytes);
priv->rx_bytes -= rsize;
val = readl(priv->base + SSI_RXDR);
if (priv->rx_buf) {
switch (rsize) {
case 1:
*priv->rx_buf = val;
break;
case 2:
put_unaligned_le16(val, priv->rx_buf);
break;
case 4:
put_unaligned_le32(val, priv->rx_buf);
break;
}
priv->rx_buf += rsize;
}
}
static void uniphier_spi_fill_tx_fifo(struct uniphier_spi_priv *priv)
{
unsigned int tx_count;
u32 val;
tx_count = DIV_ROUND_UP(priv->tx_bytes,
bytes_per_word(priv->bits_per_word));
tx_count = min(tx_count, SSI_FIFO_DEPTH);
/* set fifo threshold */
val = readl(priv->base + SSI_FC);
val &= ~(SSI_FC_TXFTH_MASK | SSI_FC_RXFTH_MASK);
val |= FIELD_PREP(SSI_FC_TXFTH_MASK, tx_count);
val |= FIELD_PREP(SSI_FC_RXFTH_MASK, tx_count);
writel(val, priv->base + SSI_FC);
while (tx_count--)
uniphier_spi_send(priv);
}
static void uniphier_spi_set_cs(struct spi_device *spi, bool enable)
{
struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
u32 val;
val = readl(priv->base + SSI_FPS);
if (enable)
val |= SSI_FPS_FSPOL;
else
val &= ~SSI_FPS_FSPOL;
writel(val, priv->base + SSI_FPS);
}
static int uniphier_spi_transfer_one(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *t)
{
struct uniphier_spi_priv *priv = spi_master_get_devdata(master);
int status;
uniphier_spi_setup_transfer(spi, t);
reinit_completion(&priv->xfer_done);
uniphier_spi_fill_tx_fifo(priv);
uniphier_spi_irq_enable(spi, SSI_IE_RCIE | SSI_IE_RORIE);
status = wait_for_completion_timeout(&priv->xfer_done,
msecs_to_jiffies(SSI_TIMEOUT_MS));
uniphier_spi_irq_disable(spi, SSI_IE_RCIE | SSI_IE_RORIE);
if (status < 0)
return status;
return priv->error;
}
static int uniphier_spi_prepare_transfer_hardware(struct spi_master *master)
{
struct uniphier_spi_priv *priv = spi_master_get_devdata(master);
writel(SSI_CTL_EN, priv->base + SSI_CTL);
return 0;
}
static int uniphier_spi_unprepare_transfer_hardware(struct spi_master *master)
{
struct uniphier_spi_priv *priv = spi_master_get_devdata(master);
writel(0, priv->base + SSI_CTL);
return 0;
}
static irqreturn_t uniphier_spi_handler(int irq, void *dev_id)
{
struct uniphier_spi_priv *priv = dev_id;
u32 val, stat;
stat = readl(priv->base + SSI_IS);
val = SSI_IC_TCIC | SSI_IC_RCIC | SSI_IC_RORIC;
writel(val, priv->base + SSI_IC);
/* rx fifo overrun */
if (stat & SSI_IS_RORID) {
priv->error = -EIO;
goto done;
}
/* rx complete */
if ((stat & SSI_IS_RCID) && (stat & SSI_IS_RXRS)) {
while ((readl(priv->base + SSI_SR) & SSI_SR_RNE) &&
(priv->rx_bytes - priv->tx_bytes) > 0)
uniphier_spi_recv(priv);
if ((readl(priv->base + SSI_SR) & SSI_SR_RNE) ||
(priv->rx_bytes != priv->tx_bytes)) {
priv->error = -EIO;
goto done;
} else if (priv->rx_bytes == 0)
goto done;
/* next tx transfer */
uniphier_spi_fill_tx_fifo(priv);
return IRQ_HANDLED;
}
return IRQ_NONE;
done:
complete(&priv->xfer_done);
return IRQ_HANDLED;
}
static int uniphier_spi_probe(struct platform_device *pdev)
{
struct uniphier_spi_priv *priv;
struct spi_master *master;
struct resource *res;
unsigned long clk_rate;
int irq;
int ret;
master = spi_alloc_master(&pdev->dev, sizeof(*priv));
if (!master)
return -ENOMEM;
platform_set_drvdata(pdev, master);
priv = spi_master_get_devdata(master);
priv->master = master;
priv->is_save_param = false;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(priv->base)) {
ret = PTR_ERR(priv->base);
goto out_master_put;
}
priv->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(priv->clk)) {
dev_err(&pdev->dev, "failed to get clock\n");
ret = PTR_ERR(priv->clk);
goto out_master_put;
}
ret = clk_prepare_enable(priv->clk);
if (ret)
goto out_master_put;
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "failed to get IRQ\n");
ret = irq;
goto out_disable_clk;
}
ret = devm_request_irq(&pdev->dev, irq, uniphier_spi_handler,
0, "uniphier-spi", priv);
if (ret) {
dev_err(&pdev->dev, "failed to request IRQ\n");
goto out_disable_clk;
}
init_completion(&priv->xfer_done);
clk_rate = clk_get_rate(priv->clk);
master->max_speed_hz = DIV_ROUND_UP(clk_rate, SSI_MIN_CLK_DIVIDER);
master->min_speed_hz = DIV_ROUND_UP(clk_rate, SSI_MAX_CLK_DIVIDER);
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
master->dev.of_node = pdev->dev.of_node;
master->bus_num = pdev->id;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
master->set_cs = uniphier_spi_set_cs;
master->transfer_one = uniphier_spi_transfer_one;
master->prepare_transfer_hardware
= uniphier_spi_prepare_transfer_hardware;
master->unprepare_transfer_hardware
= uniphier_spi_unprepare_transfer_hardware;
master->num_chipselect = 1;
ret = devm_spi_register_master(&pdev->dev, master);
if (ret)
goto out_disable_clk;
return 0;
out_disable_clk:
clk_disable_unprepare(priv->clk);
out_master_put:
spi_master_put(master);
return ret;
}
static int uniphier_spi_remove(struct platform_device *pdev)
{
struct uniphier_spi_priv *priv = platform_get_drvdata(pdev);
clk_disable_unprepare(priv->clk);
return 0;
}
static const struct of_device_id uniphier_spi_match[] = {
{ .compatible = "socionext,uniphier-scssi" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, uniphier_spi_match);
static struct platform_driver uniphier_spi_driver = {
.probe = uniphier_spi_probe,
.remove = uniphier_spi_remove,
.driver = {
.name = "uniphier-spi",
.of_match_table = uniphier_spi_match,
},
};
module_platform_driver(uniphier_spi_driver);
MODULE_AUTHOR("Kunihiko Hayashi <hayashi.kunihiko@socionext.com>");
MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>");
MODULE_DESCRIPTION("Socionext UniPhier SPI controller driver");
MODULE_LICENSE("GPL v2");
