/*
* SuperH HSPI bus driver
*
* Copyright (C) 2011 Kuninori Morimoto
*
* Based on spi-sh.c:
* Based on pxa2xx_spi.c:
* Copyright (C) 2011 Renesas Solutions Corp.
* Copyright (C) 2005 Stephen Street / StreetFire Sound Labs
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/io.h>
#include <linux/spi/spi.h>
#include <linux/spi/sh_hspi.h>
#define SPCR 0x00
#define SPSR 0x04
#define SPSCR 0x08
#define SPTBR 0x0C
#define SPRBR 0x10
#define SPCR2 0x14
/* SPSR */
#define RXFL (1 << 2)
struct hspi_priv {
void __iomem *addr;
struct spi_master *master;
struct device *dev;
struct clk *clk;
};
/*
* basic function
*/
static void hspi_write(struct hspi_priv *hspi, int reg, u32 val)
{
iowrite32(val, hspi->addr + reg);
}
static u32 hspi_read(struct hspi_priv *hspi, int reg)
{
return ioread32(hspi->addr + reg);
}
static void hspi_bit_set(struct hspi_priv *hspi, int reg, u32 mask, u32 set)
{
u32 val = hspi_read(hspi, reg);
val &= ~mask;
val |= set & mask;
hspi_write(hspi, reg, val);
}
/*
* transfer function
*/
static int hspi_status_check_timeout(struct hspi_priv *hspi, u32 mask, u32 val)
{
int t = 256;
while (t--) {
if ((mask & hspi_read(hspi, SPSR)) == val)
return 0;
udelay(10);
}
dev_err(hspi->dev, "timeout\n");
return -ETIMEDOUT;
}
/*
* spi master function
*/
#define hspi_hw_cs_enable(hspi) hspi_hw_cs_ctrl(hspi, 0)
#define hspi_hw_cs_disable(hspi) hspi_hw_cs_ctrl(hspi, 1)
static void hspi_hw_cs_ctrl(struct hspi_priv *hspi, int hi)
{
hspi_bit_set(hspi, SPSCR, (1 << 6), (hi) << 6);
}
static void hspi_hw_setup(struct hspi_priv *hspi,
struct spi_message *msg,
struct spi_transfer *t)
{
struct spi_device *spi = msg->spi;
struct device *dev = hspi->dev;
u32 spcr, idiv_clk;
u32 rate, best_rate, min, tmp;
/*
* find best IDIV/CLKCx settings
*/
min = ~0;
best_rate = 0;
spcr = 0;
for (idiv_clk = 0x00; idiv_clk <= 0x3F; idiv_clk++) {
rate = clk_get_rate(hspi->clk);
/* IDIV calculation */
if (idiv_clk & (1 << 5))
rate /= 128;
else
rate /= 16;
/* CLKCx calculation */
rate /= (((idiv_clk & 0x1F) + 1) * 2);
/* save best settings */
tmp = abs(t->speed_hz - rate);
if (tmp < min) {
min = tmp;
spcr = idiv_clk;
best_rate = rate;
}
}
if (spi->mode & SPI_CPHA)
spcr |= 1 << 7;
if (spi->mode & SPI_CPOL)
spcr |= 1 << 6;
dev_dbg(dev, "speed %d/%d\n", t->speed_hz, best_rate);
hspi_write(hspi, SPCR, spcr);
hspi_write(hspi, SPSR, 0x0);
hspi_write(hspi, SPSCR, 0x21); /* master mode / CS control */
}
static int hspi_transfer_one_message(struct spi_master *master,
struct spi_message *msg)
{
struct hspi_priv *hspi = spi_master_get_devdata(master);
struct spi_transfer *t;
u32 tx;
u32 rx;
int ret, i;
unsigned int cs_change;
const int nsecs = 50;
dev_dbg(hspi->dev, "%s\n", __func__);
cs_change = 1;
ret = 0;
list_for_each_entry(t, &msg->transfers, transfer_list) {
if (cs_change) {
hspi_hw_setup(hspi, msg, t);
hspi_hw_cs_enable(hspi);
ndelay(nsecs);
}
cs_change = t->cs_change;
for (i = 0; i < t->len; i++) {
/* wait remains */
ret = hspi_status_check_timeout(hspi, 0x1, 0);
if (ret < 0)
break;
tx = 0;
if (t->tx_buf)
tx = (u32)((u8 *)t->tx_buf)[i];
hspi_write(hspi, SPTBR, tx);
/* wait receive */
ret = hspi_status_check_timeout(hspi, 0x4, 0x4);
if (ret < 0)
break;
rx = hspi_read(hspi, SPRBR);
if (t->rx_buf)
((u8 *)t->rx_buf)[i] = (u8)rx;
}
msg->actual_length += t->len;
if (t->delay_usecs)
udelay(t->delay_usecs);
if (cs_change) {
ndelay(nsecs);
hspi_hw_cs_disable(hspi);
ndelay(nsecs);
}
}
msg->status = ret;
if (!cs_change) {
ndelay(nsecs);
hspi_hw_cs_disable(hspi);
}
spi_finalize_current_message(master);
return ret;
}
static int hspi_probe(struct platform_device *pdev)
{
struct resource *res;
struct spi_master *master;
struct hspi_priv *hspi;
struct clk *clk;
int ret;
/* get base addr */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "invalid resource\n");
return -EINVAL;
}
master = spi_alloc_master(&pdev->dev, sizeof(*hspi));
if (!master) {
dev_err(&pdev->dev, "spi_alloc_master error.\n");
return -ENOMEM;
}
clk = clk_get(&pdev->dev, NULL);
if (IS_ERR(clk)) {
dev_err(&pdev->dev, "couldn't get clock\n");
ret = -EINVAL;
goto error0;
}
hspi = spi_master_get_devdata(master);
platform_set_drvdata(pdev, hspi);
/* init hspi */
hspi->master = master;
hspi->dev = &pdev->dev;
hspi->clk = clk;
hspi->addr = devm_ioremap(hspi->dev,
res->start, resource_size(res));
if (!hspi->addr) {
dev_err(&pdev->dev, "ioremap error.\n");
ret = -ENOMEM;
goto error1;
}
pm_runtime_enable(&pdev->dev);
master->bus_num = pdev->id;
master->mode_bits = SPI_CPOL | SPI_CPHA;
master->dev.of_node = pdev->dev.of_node;
master->auto_runtime_pm = true;
master->transfer_one_message = hspi_transfer_one_message;
master->bits_per_word_mask = SPI_BPW_MASK(8);
ret = devm_spi_register_master(&pdev->dev, master);
if (ret < 0) {
dev_err(&pdev->dev, "spi_register_master error.\n");
goto error2;
}
return 0;
error2:
pm_runtime_disable(&pdev->dev);
error1:
clk_put(clk);
error0:
spi_master_put(master);
return ret;
}
static int hspi_remove(struct platform_device *pdev)
{
struct hspi_priv *hspi = platform_get_drvdata(pdev);
pm_runtime_disable(&pdev->dev);
clk_put(hspi->clk);
return 0;
}
static const struct of_device_id hspi_of_match[] = {
{ .compatible = "renesas,hspi", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, hspi_of_match);
static struct platform_driver hspi_driver = {
.probe = hspi_probe,
.remove = hspi_remove,
.driver = {
.name = "sh-hspi",
.owner = THIS_MODULE,
.of_match_table = hspi_of_match,
},
};
module_platform_driver(hspi_driver);
MODULE_DESCRIPTION("SuperH HSPI bus driver");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
MODULE_ALIAS("platform:sh-hspi");
