352 строки
8.0 KiB
C
352 строки
8.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* NXP SC18IS602/603 SPI driver
|
|
*
|
|
* Copyright (C) Guenter Roeck <linux@roeck-us.net>
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/err.h>
|
|
#include <linux/module.h>
|
|
#include <linux/spi/spi.h>
|
|
#include <linux/i2c.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/pm_runtime.h>
|
|
#include <linux/of_device.h>
|
|
#include <linux/of.h>
|
|
#include <linux/platform_data/sc18is602.h>
|
|
#include <linux/gpio/consumer.h>
|
|
|
|
enum chips { sc18is602, sc18is602b, sc18is603 };
|
|
|
|
#define SC18IS602_BUFSIZ 200
|
|
#define SC18IS602_CLOCK 7372000
|
|
|
|
#define SC18IS602_MODE_CPHA BIT(2)
|
|
#define SC18IS602_MODE_CPOL BIT(3)
|
|
#define SC18IS602_MODE_LSB_FIRST BIT(5)
|
|
#define SC18IS602_MODE_CLOCK_DIV_4 0x0
|
|
#define SC18IS602_MODE_CLOCK_DIV_16 0x1
|
|
#define SC18IS602_MODE_CLOCK_DIV_64 0x2
|
|
#define SC18IS602_MODE_CLOCK_DIV_128 0x3
|
|
|
|
struct sc18is602 {
|
|
struct spi_master *master;
|
|
struct device *dev;
|
|
u8 ctrl;
|
|
u32 freq;
|
|
u32 speed;
|
|
|
|
/* I2C data */
|
|
struct i2c_client *client;
|
|
enum chips id;
|
|
u8 buffer[SC18IS602_BUFSIZ + 1];
|
|
int tlen; /* Data queued for tx in buffer */
|
|
int rindex; /* Receive data index in buffer */
|
|
|
|
struct gpio_desc *reset;
|
|
};
|
|
|
|
static int sc18is602_wait_ready(struct sc18is602 *hw, int len)
|
|
{
|
|
int i, err;
|
|
int usecs = 1000000 * len / hw->speed + 1;
|
|
u8 dummy[1];
|
|
|
|
for (i = 0; i < 10; i++) {
|
|
err = i2c_master_recv(hw->client, dummy, 1);
|
|
if (err >= 0)
|
|
return 0;
|
|
usleep_range(usecs, usecs * 2);
|
|
}
|
|
return -ETIMEDOUT;
|
|
}
|
|
|
|
static int sc18is602_txrx(struct sc18is602 *hw, struct spi_message *msg,
|
|
struct spi_transfer *t, bool do_transfer)
|
|
{
|
|
unsigned int len = t->len;
|
|
int ret;
|
|
|
|
if (hw->tlen == 0) {
|
|
/* First byte (I2C command) is chip select */
|
|
hw->buffer[0] = 1 << msg->spi->chip_select;
|
|
hw->tlen = 1;
|
|
hw->rindex = 0;
|
|
}
|
|
/*
|
|
* We can not immediately send data to the chip, since each I2C message
|
|
* resembles a full SPI message (from CS active to CS inactive).
|
|
* Enqueue messages up to the first read or until do_transfer is true.
|
|
*/
|
|
if (t->tx_buf) {
|
|
memcpy(&hw->buffer[hw->tlen], t->tx_buf, len);
|
|
hw->tlen += len;
|
|
if (t->rx_buf)
|
|
do_transfer = true;
|
|
else
|
|
hw->rindex = hw->tlen - 1;
|
|
} else if (t->rx_buf) {
|
|
/*
|
|
* For receive-only transfers we still need to perform a dummy
|
|
* write to receive data from the SPI chip.
|
|
* Read data starts at the end of transmit data (minus 1 to
|
|
* account for CS).
|
|
*/
|
|
hw->rindex = hw->tlen - 1;
|
|
memset(&hw->buffer[hw->tlen], 0, len);
|
|
hw->tlen += len;
|
|
do_transfer = true;
|
|
}
|
|
|
|
if (do_transfer && hw->tlen > 1) {
|
|
ret = sc18is602_wait_ready(hw, SC18IS602_BUFSIZ);
|
|
if (ret < 0)
|
|
return ret;
|
|
ret = i2c_master_send(hw->client, hw->buffer, hw->tlen);
|
|
if (ret < 0)
|
|
return ret;
|
|
if (ret != hw->tlen)
|
|
return -EIO;
|
|
|
|
if (t->rx_buf) {
|
|
int rlen = hw->rindex + len;
|
|
|
|
ret = sc18is602_wait_ready(hw, hw->tlen);
|
|
if (ret < 0)
|
|
return ret;
|
|
ret = i2c_master_recv(hw->client, hw->buffer, rlen);
|
|
if (ret < 0)
|
|
return ret;
|
|
if (ret != rlen)
|
|
return -EIO;
|
|
memcpy(t->rx_buf, &hw->buffer[hw->rindex], len);
|
|
}
|
|
hw->tlen = 0;
|
|
}
|
|
return len;
|
|
}
|
|
|
|
static int sc18is602_setup_transfer(struct sc18is602 *hw, u32 hz, u8 mode)
|
|
{
|
|
u8 ctrl = 0;
|
|
int ret;
|
|
|
|
if (mode & SPI_CPHA)
|
|
ctrl |= SC18IS602_MODE_CPHA;
|
|
if (mode & SPI_CPOL)
|
|
ctrl |= SC18IS602_MODE_CPOL;
|
|
if (mode & SPI_LSB_FIRST)
|
|
ctrl |= SC18IS602_MODE_LSB_FIRST;
|
|
|
|
/* Find the closest clock speed */
|
|
if (hz >= hw->freq / 4) {
|
|
ctrl |= SC18IS602_MODE_CLOCK_DIV_4;
|
|
hw->speed = hw->freq / 4;
|
|
} else if (hz >= hw->freq / 16) {
|
|
ctrl |= SC18IS602_MODE_CLOCK_DIV_16;
|
|
hw->speed = hw->freq / 16;
|
|
} else if (hz >= hw->freq / 64) {
|
|
ctrl |= SC18IS602_MODE_CLOCK_DIV_64;
|
|
hw->speed = hw->freq / 64;
|
|
} else {
|
|
ctrl |= SC18IS602_MODE_CLOCK_DIV_128;
|
|
hw->speed = hw->freq / 128;
|
|
}
|
|
|
|
/*
|
|
* Don't do anything if the control value did not change. The initial
|
|
* value of 0xff for hw->ctrl ensures that the correct mode will be set
|
|
* with the first call to this function.
|
|
*/
|
|
if (ctrl == hw->ctrl)
|
|
return 0;
|
|
|
|
ret = i2c_smbus_write_byte_data(hw->client, 0xf0, ctrl);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
hw->ctrl = ctrl;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int sc18is602_check_transfer(struct spi_device *spi,
|
|
struct spi_transfer *t, int tlen)
|
|
{
|
|
if (t && t->len + tlen > SC18IS602_BUFSIZ)
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int sc18is602_transfer_one(struct spi_master *master,
|
|
struct spi_message *m)
|
|
{
|
|
struct sc18is602 *hw = spi_master_get_devdata(master);
|
|
struct spi_device *spi = m->spi;
|
|
struct spi_transfer *t;
|
|
int status = 0;
|
|
|
|
hw->tlen = 0;
|
|
list_for_each_entry(t, &m->transfers, transfer_list) {
|
|
bool do_transfer;
|
|
|
|
status = sc18is602_check_transfer(spi, t, hw->tlen);
|
|
if (status < 0)
|
|
break;
|
|
|
|
status = sc18is602_setup_transfer(hw, t->speed_hz, spi->mode);
|
|
if (status < 0)
|
|
break;
|
|
|
|
do_transfer = t->cs_change || list_is_last(&t->transfer_list,
|
|
&m->transfers);
|
|
|
|
if (t->len) {
|
|
status = sc18is602_txrx(hw, m, t, do_transfer);
|
|
if (status < 0)
|
|
break;
|
|
m->actual_length += status;
|
|
}
|
|
status = 0;
|
|
|
|
if (t->delay_usecs)
|
|
udelay(t->delay_usecs);
|
|
}
|
|
m->status = status;
|
|
spi_finalize_current_message(master);
|
|
|
|
return status;
|
|
}
|
|
|
|
static int sc18is602_setup(struct spi_device *spi)
|
|
{
|
|
struct sc18is602 *hw = spi_master_get_devdata(spi->master);
|
|
|
|
/* SC18IS602 does not support CS2 */
|
|
if (hw->id == sc18is602 && spi->chip_select == 2)
|
|
return -ENXIO;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int sc18is602_probe(struct i2c_client *client,
|
|
const struct i2c_device_id *id)
|
|
{
|
|
struct device *dev = &client->dev;
|
|
struct device_node *np = dev->of_node;
|
|
struct sc18is602_platform_data *pdata = dev_get_platdata(dev);
|
|
struct sc18is602 *hw;
|
|
struct spi_master *master;
|
|
int error;
|
|
|
|
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
|
|
I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
|
|
return -EINVAL;
|
|
|
|
master = spi_alloc_master(dev, sizeof(struct sc18is602));
|
|
if (!master)
|
|
return -ENOMEM;
|
|
|
|
hw = spi_master_get_devdata(master);
|
|
i2c_set_clientdata(client, hw);
|
|
|
|
/* assert reset and then release */
|
|
hw->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
|
|
if (IS_ERR(hw->reset))
|
|
return PTR_ERR(hw->reset);
|
|
gpiod_set_value_cansleep(hw->reset, 0);
|
|
|
|
hw->master = master;
|
|
hw->client = client;
|
|
hw->dev = dev;
|
|
hw->ctrl = 0xff;
|
|
|
|
if (client->dev.of_node)
|
|
hw->id = (enum chips)of_device_get_match_data(&client->dev);
|
|
else
|
|
hw->id = id->driver_data;
|
|
|
|
switch (hw->id) {
|
|
case sc18is602:
|
|
case sc18is602b:
|
|
master->num_chipselect = 4;
|
|
hw->freq = SC18IS602_CLOCK;
|
|
break;
|
|
case sc18is603:
|
|
master->num_chipselect = 2;
|
|
if (pdata) {
|
|
hw->freq = pdata->clock_frequency;
|
|
} else {
|
|
const __be32 *val;
|
|
int len;
|
|
|
|
val = of_get_property(np, "clock-frequency", &len);
|
|
if (val && len >= sizeof(__be32))
|
|
hw->freq = be32_to_cpup(val);
|
|
}
|
|
if (!hw->freq)
|
|
hw->freq = SC18IS602_CLOCK;
|
|
break;
|
|
}
|
|
master->bus_num = np ? -1 : client->adapter->nr;
|
|
master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST;
|
|
master->bits_per_word_mask = SPI_BPW_MASK(8);
|
|
master->setup = sc18is602_setup;
|
|
master->transfer_one_message = sc18is602_transfer_one;
|
|
master->dev.of_node = np;
|
|
master->min_speed_hz = hw->freq / 128;
|
|
master->max_speed_hz = hw->freq / 4;
|
|
|
|
error = devm_spi_register_master(dev, master);
|
|
if (error)
|
|
goto error_reg;
|
|
|
|
return 0;
|
|
|
|
error_reg:
|
|
spi_master_put(master);
|
|
return error;
|
|
}
|
|
|
|
static const struct i2c_device_id sc18is602_id[] = {
|
|
{ "sc18is602", sc18is602 },
|
|
{ "sc18is602b", sc18is602b },
|
|
{ "sc18is603", sc18is603 },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(i2c, sc18is602_id);
|
|
|
|
static const struct of_device_id sc18is602_of_match[] = {
|
|
{
|
|
.compatible = "nxp,sc18is602",
|
|
.data = (void *)sc18is602
|
|
},
|
|
{
|
|
.compatible = "nxp,sc18is602b",
|
|
.data = (void *)sc18is602b
|
|
},
|
|
{
|
|
.compatible = "nxp,sc18is603",
|
|
.data = (void *)sc18is603
|
|
},
|
|
{ },
|
|
};
|
|
MODULE_DEVICE_TABLE(of, sc18is602_of_match);
|
|
|
|
static struct i2c_driver sc18is602_driver = {
|
|
.driver = {
|
|
.name = "sc18is602",
|
|
.of_match_table = of_match_ptr(sc18is602_of_match),
|
|
},
|
|
.probe = sc18is602_probe,
|
|
.id_table = sc18is602_id,
|
|
};
|
|
|
|
module_i2c_driver(sc18is602_driver);
|
|
|
|
MODULE_DESCRIPTION("SC18IC602/603 SPI Master Driver");
|
|
MODULE_AUTHOR("Guenter Roeck");
|
|
MODULE_LICENSE("GPL");
|