349 строки
8.2 KiB
C
349 строки
8.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* NXP SC18IS602/603 SPI driver
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*
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* Copyright (C) Guenter Roeck <linux@roeck-us.net>
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*/
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#include <linux/kernel.h>
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/spi/spi.h>
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#include <linux/i2c.h>
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#include <linux/delay.h>
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#include <linux/pm_runtime.h>
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#include <linux/of_device.h>
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#include <linux/of.h>
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#include <linux/platform_data/sc18is602.h>
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#include <linux/gpio/consumer.h>
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enum chips { sc18is602, sc18is602b, sc18is603 };
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#define SC18IS602_BUFSIZ 200
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#define SC18IS602_CLOCK 7372000
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#define SC18IS602_MODE_CPHA BIT(2)
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#define SC18IS602_MODE_CPOL BIT(3)
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#define SC18IS602_MODE_LSB_FIRST BIT(5)
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#define SC18IS602_MODE_CLOCK_DIV_4 0x0
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#define SC18IS602_MODE_CLOCK_DIV_16 0x1
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#define SC18IS602_MODE_CLOCK_DIV_64 0x2
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#define SC18IS602_MODE_CLOCK_DIV_128 0x3
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struct sc18is602 {
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struct spi_master *master;
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struct device *dev;
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u8 ctrl;
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u32 freq;
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u32 speed;
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/* I2C data */
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struct i2c_client *client;
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enum chips id;
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u8 buffer[SC18IS602_BUFSIZ + 1];
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int tlen; /* Data queued for tx in buffer */
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int rindex; /* Receive data index in buffer */
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struct gpio_desc *reset;
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};
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static int sc18is602_wait_ready(struct sc18is602 *hw, int len)
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{
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int i, err;
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int usecs = 1000000 * len / hw->speed + 1;
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u8 dummy[1];
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for (i = 0; i < 10; i++) {
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err = i2c_master_recv(hw->client, dummy, 1);
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if (err >= 0)
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return 0;
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usleep_range(usecs, usecs * 2);
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}
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return -ETIMEDOUT;
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}
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static int sc18is602_txrx(struct sc18is602 *hw, struct spi_message *msg,
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struct spi_transfer *t, bool do_transfer)
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{
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unsigned int len = t->len;
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int ret;
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if (hw->tlen == 0) {
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/* First byte (I2C command) is chip select */
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hw->buffer[0] = 1 << msg->spi->chip_select;
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hw->tlen = 1;
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hw->rindex = 0;
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}
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/*
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* We can not immediately send data to the chip, since each I2C message
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* resembles a full SPI message (from CS active to CS inactive).
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* Enqueue messages up to the first read or until do_transfer is true.
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*/
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if (t->tx_buf) {
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memcpy(&hw->buffer[hw->tlen], t->tx_buf, len);
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hw->tlen += len;
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if (t->rx_buf)
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do_transfer = true;
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else
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hw->rindex = hw->tlen - 1;
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} else if (t->rx_buf) {
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/*
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* For receive-only transfers we still need to perform a dummy
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* write to receive data from the SPI chip.
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* Read data starts at the end of transmit data (minus 1 to
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* account for CS).
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*/
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hw->rindex = hw->tlen - 1;
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memset(&hw->buffer[hw->tlen], 0, len);
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hw->tlen += len;
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do_transfer = true;
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}
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if (do_transfer && hw->tlen > 1) {
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ret = sc18is602_wait_ready(hw, SC18IS602_BUFSIZ);
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if (ret < 0)
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return ret;
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ret = i2c_master_send(hw->client, hw->buffer, hw->tlen);
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if (ret < 0)
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return ret;
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if (ret != hw->tlen)
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return -EIO;
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if (t->rx_buf) {
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int rlen = hw->rindex + len;
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ret = sc18is602_wait_ready(hw, hw->tlen);
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if (ret < 0)
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return ret;
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ret = i2c_master_recv(hw->client, hw->buffer, rlen);
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if (ret < 0)
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return ret;
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if (ret != rlen)
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return -EIO;
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memcpy(t->rx_buf, &hw->buffer[hw->rindex], len);
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}
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hw->tlen = 0;
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}
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return len;
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}
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static int sc18is602_setup_transfer(struct sc18is602 *hw, u32 hz, u8 mode)
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{
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u8 ctrl = 0;
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int ret;
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if (mode & SPI_CPHA)
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ctrl |= SC18IS602_MODE_CPHA;
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if (mode & SPI_CPOL)
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ctrl |= SC18IS602_MODE_CPOL;
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if (mode & SPI_LSB_FIRST)
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ctrl |= SC18IS602_MODE_LSB_FIRST;
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/* Find the closest clock speed */
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if (hz >= hw->freq / 4) {
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ctrl |= SC18IS602_MODE_CLOCK_DIV_4;
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hw->speed = hw->freq / 4;
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} else if (hz >= hw->freq / 16) {
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ctrl |= SC18IS602_MODE_CLOCK_DIV_16;
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hw->speed = hw->freq / 16;
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} else if (hz >= hw->freq / 64) {
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ctrl |= SC18IS602_MODE_CLOCK_DIV_64;
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hw->speed = hw->freq / 64;
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} else {
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ctrl |= SC18IS602_MODE_CLOCK_DIV_128;
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hw->speed = hw->freq / 128;
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}
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/*
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* Don't do anything if the control value did not change. The initial
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* value of 0xff for hw->ctrl ensures that the correct mode will be set
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* with the first call to this function.
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*/
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if (ctrl == hw->ctrl)
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return 0;
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ret = i2c_smbus_write_byte_data(hw->client, 0xf0, ctrl);
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if (ret < 0)
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return ret;
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hw->ctrl = ctrl;
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return 0;
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}
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static int sc18is602_check_transfer(struct spi_device *spi,
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struct spi_transfer *t, int tlen)
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{
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if (t && t->len + tlen > SC18IS602_BUFSIZ + 1)
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return -EINVAL;
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return 0;
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}
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static int sc18is602_transfer_one(struct spi_master *master,
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struct spi_message *m)
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{
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struct sc18is602 *hw = spi_master_get_devdata(master);
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struct spi_device *spi = m->spi;
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struct spi_transfer *t;
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int status = 0;
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hw->tlen = 0;
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list_for_each_entry(t, &m->transfers, transfer_list) {
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bool do_transfer;
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status = sc18is602_check_transfer(spi, t, hw->tlen);
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if (status < 0)
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break;
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status = sc18is602_setup_transfer(hw, t->speed_hz, spi->mode);
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if (status < 0)
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break;
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do_transfer = t->cs_change || list_is_last(&t->transfer_list,
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&m->transfers);
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if (t->len) {
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status = sc18is602_txrx(hw, m, t, do_transfer);
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if (status < 0)
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break;
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m->actual_length += status;
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}
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status = 0;
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spi_transfer_delay_exec(t);
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}
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m->status = status;
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spi_finalize_current_message(master);
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return status;
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}
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static size_t sc18is602_max_transfer_size(struct spi_device *spi)
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{
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return SC18IS602_BUFSIZ;
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}
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static int sc18is602_setup(struct spi_device *spi)
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{
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struct sc18is602 *hw = spi_master_get_devdata(spi->master);
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/* SC18IS602 does not support CS2 */
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if (hw->id == sc18is602 && spi->chip_select == 2)
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return -ENXIO;
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return 0;
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}
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static int sc18is602_probe(struct i2c_client *client)
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{
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const struct i2c_device_id *id = i2c_client_get_device_id(client);
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struct device *dev = &client->dev;
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struct device_node *np = dev->of_node;
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struct sc18is602_platform_data *pdata = dev_get_platdata(dev);
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struct sc18is602 *hw;
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struct spi_master *master;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
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I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
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return -EINVAL;
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master = devm_spi_alloc_master(dev, sizeof(struct sc18is602));
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if (!master)
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return -ENOMEM;
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hw = spi_master_get_devdata(master);
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i2c_set_clientdata(client, hw);
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/* assert reset and then release */
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hw->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
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if (IS_ERR(hw->reset))
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return PTR_ERR(hw->reset);
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gpiod_set_value_cansleep(hw->reset, 0);
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hw->master = master;
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hw->client = client;
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hw->dev = dev;
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hw->ctrl = 0xff;
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if (client->dev.of_node)
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hw->id = (enum chips)of_device_get_match_data(&client->dev);
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else
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hw->id = id->driver_data;
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switch (hw->id) {
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case sc18is602:
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case sc18is602b:
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master->num_chipselect = 4;
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hw->freq = SC18IS602_CLOCK;
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break;
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case sc18is603:
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master->num_chipselect = 2;
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if (pdata) {
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hw->freq = pdata->clock_frequency;
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} else {
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const __be32 *val;
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int len;
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val = of_get_property(np, "clock-frequency", &len);
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if (val && len >= sizeof(__be32))
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hw->freq = be32_to_cpup(val);
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}
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if (!hw->freq)
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hw->freq = SC18IS602_CLOCK;
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break;
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}
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master->bus_num = np ? -1 : client->adapter->nr;
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master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST;
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master->bits_per_word_mask = SPI_BPW_MASK(8);
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master->setup = sc18is602_setup;
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master->transfer_one_message = sc18is602_transfer_one;
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master->max_transfer_size = sc18is602_max_transfer_size;
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master->max_message_size = sc18is602_max_transfer_size;
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master->dev.of_node = np;
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master->min_speed_hz = hw->freq / 128;
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master->max_speed_hz = hw->freq / 4;
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return devm_spi_register_master(dev, master);
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}
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static const struct i2c_device_id sc18is602_id[] = {
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{ "sc18is602", sc18is602 },
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{ "sc18is602b", sc18is602b },
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{ "sc18is603", sc18is603 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, sc18is602_id);
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static const struct of_device_id sc18is602_of_match[] = {
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{
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.compatible = "nxp,sc18is602",
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.data = (void *)sc18is602
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},
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{
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.compatible = "nxp,sc18is602b",
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.data = (void *)sc18is602b
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},
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{
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.compatible = "nxp,sc18is603",
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.data = (void *)sc18is603
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},
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{ },
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};
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MODULE_DEVICE_TABLE(of, sc18is602_of_match);
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static struct i2c_driver sc18is602_driver = {
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.driver = {
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.name = "sc18is602",
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.of_match_table = of_match_ptr(sc18is602_of_match),
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},
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.probe_new = sc18is602_probe,
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.id_table = sc18is602_id,
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};
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module_i2c_driver(sc18is602_driver);
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MODULE_DESCRIPTION("SC18IS602/603 SPI Master Driver");
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MODULE_AUTHOR("Guenter Roeck");
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MODULE_LICENSE("GPL");
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