2 * NXP SC18IS602/603 SPI driver
4 * Copyright (C) Guenter Roeck <linux@roeck-us.net>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 #include <linux/kernel.h>
22 #include <linux/err.h>
23 #include <linux/module.h>
24 #include <linux/spi/spi.h>
25 #include <linux/i2c.h>
26 #include <linux/delay.h>
27 #include <linux/pm_runtime.h>
29 #include <linux/platform_data/sc18is602.h>
31 enum chips { sc18is602, sc18is602b, sc18is603 };
33 #define SC18IS602_BUFSIZ 200
34 #define SC18IS602_CLOCK 7372000
36 #define SC18IS602_MODE_CPHA BIT(2)
37 #define SC18IS602_MODE_CPOL BIT(3)
38 #define SC18IS602_MODE_LSB_FIRST BIT(5)
39 #define SC18IS602_MODE_CLOCK_DIV_4 0x0
40 #define SC18IS602_MODE_CLOCK_DIV_16 0x1
41 #define SC18IS602_MODE_CLOCK_DIV_64 0x2
42 #define SC18IS602_MODE_CLOCK_DIV_128 0x3
45 struct spi_master *master;
52 struct i2c_client *client;
54 u8 buffer[SC18IS602_BUFSIZ + 1];
55 int tlen; /* Data queued for tx in buffer */
56 int rindex; /* Receive data index in buffer */
59 static int sc18is602_wait_ready(struct sc18is602 *hw, int len)
62 int usecs = 1000000 * len / hw->speed + 1;
65 for (i = 0; i < 10; i++) {
66 err = i2c_master_recv(hw->client, dummy, 1);
69 usleep_range(usecs, usecs * 2);
74 static int sc18is602_txrx(struct sc18is602 *hw, struct spi_message *msg,
75 struct spi_transfer *t, bool do_transfer)
77 unsigned int len = t->len;
81 /* First byte (I2C command) is chip select */
82 hw->buffer[0] = 1 << msg->spi->chip_select;
87 * We can not immediately send data to the chip, since each I2C message
88 * resembles a full SPI message (from CS active to CS inactive).
89 * Enqueue messages up to the first read or until do_transfer is true.
92 memcpy(&hw->buffer[hw->tlen], t->tx_buf, len);
97 hw->rindex = hw->tlen - 1;
98 } else if (t->rx_buf) {
100 * For receive-only transfers we still need to perform a dummy
101 * write to receive data from the SPI chip.
102 * Read data starts at the end of transmit data (minus 1 to
105 hw->rindex = hw->tlen - 1;
106 memset(&hw->buffer[hw->tlen], 0, len);
111 if (do_transfer && hw->tlen > 1) {
112 ret = sc18is602_wait_ready(hw, SC18IS602_BUFSIZ);
115 ret = i2c_master_send(hw->client, hw->buffer, hw->tlen);
122 int rlen = hw->rindex + len;
124 ret = sc18is602_wait_ready(hw, hw->tlen);
127 ret = i2c_master_recv(hw->client, hw->buffer, rlen);
132 memcpy(t->rx_buf, &hw->buffer[hw->rindex], len);
139 static int sc18is602_setup_transfer(struct sc18is602 *hw, u32 hz, u8 mode)
145 ctrl |= SC18IS602_MODE_CPHA;
147 ctrl |= SC18IS602_MODE_CPOL;
148 if (mode & SPI_LSB_FIRST)
149 ctrl |= SC18IS602_MODE_LSB_FIRST;
151 /* Find the closest clock speed */
152 if (hz >= hw->freq / 4) {
153 ctrl |= SC18IS602_MODE_CLOCK_DIV_4;
154 hw->speed = hw->freq / 4;
155 } else if (hz >= hw->freq / 16) {
156 ctrl |= SC18IS602_MODE_CLOCK_DIV_16;
157 hw->speed = hw->freq / 16;
158 } else if (hz >= hw->freq / 64) {
159 ctrl |= SC18IS602_MODE_CLOCK_DIV_64;
160 hw->speed = hw->freq / 64;
162 ctrl |= SC18IS602_MODE_CLOCK_DIV_128;
163 hw->speed = hw->freq / 128;
167 * Don't do anything if the control value did not change. The initial
168 * value of 0xff for hw->ctrl ensures that the correct mode will be set
169 * with the first call to this function.
171 if (ctrl == hw->ctrl)
174 ret = i2c_smbus_write_byte_data(hw->client, 0xf0, ctrl);
183 static int sc18is602_check_transfer(struct spi_device *spi,
184 struct spi_transfer *t, int tlen)
189 if (t && t->len + tlen > SC18IS602_BUFSIZ)
192 bpw = spi->bits_per_word;
193 if (t && t->bits_per_word)
194 bpw = t->bits_per_word;
198 hz = spi->max_speed_hz;
199 if (t && t->speed_hz)
207 static int sc18is602_transfer_one(struct spi_master *master,
208 struct spi_message *m)
210 struct sc18is602 *hw = spi_master_get_devdata(master);
211 struct spi_device *spi = m->spi;
212 struct spi_transfer *t;
215 /* SC18IS602 does not support CS2 */
216 if (hw->id == sc18is602 && spi->chip_select == 2) {
222 list_for_each_entry(t, &m->transfers, transfer_list) {
223 u32 hz = t->speed_hz ? : spi->max_speed_hz;
226 status = sc18is602_check_transfer(spi, t, hw->tlen);
230 status = sc18is602_setup_transfer(hw, hz, spi->mode);
234 do_transfer = t->cs_change || list_is_last(&t->transfer_list,
238 status = sc18is602_txrx(hw, m, t, do_transfer);
241 m->actual_length += status;
246 udelay(t->delay_usecs);
250 spi_finalize_current_message(master);
255 static int sc18is602_setup(struct spi_device *spi)
257 if (!spi->bits_per_word)
258 spi->bits_per_word = 8;
260 if (spi->mode & ~(SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST))
263 return sc18is602_check_transfer(spi, NULL, 0);
266 static int sc18is602_probe(struct i2c_client *client,
267 const struct i2c_device_id *id)
269 struct device *dev = &client->dev;
270 struct device_node *np = dev->of_node;
271 struct sc18is602_platform_data *pdata = dev_get_platdata(dev);
272 struct sc18is602 *hw;
273 struct spi_master *master;
276 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
277 I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
280 master = spi_alloc_master(dev, sizeof(struct sc18is602));
284 hw = spi_master_get_devdata(master);
285 i2c_set_clientdata(client, hw);
292 hw->id = id->driver_data;
297 master->num_chipselect = 4;
298 hw->freq = SC18IS602_CLOCK;
301 master->num_chipselect = 2;
303 hw->freq = pdata->clock_frequency;
308 val = of_get_property(np, "clock-frequency", &len);
309 if (val && len >= sizeof(__be32))
310 hw->freq = be32_to_cpup(val);
313 hw->freq = SC18IS602_CLOCK;
316 master->bus_num = client->adapter->nr;
317 master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST;
318 master->setup = sc18is602_setup;
319 master->transfer_one_message = sc18is602_transfer_one;
320 master->dev.of_node = np;
322 error = devm_spi_register_master(dev, master);
329 spi_master_put(master);
333 static const struct i2c_device_id sc18is602_id[] = {
334 { "sc18is602", sc18is602 },
335 { "sc18is602b", sc18is602b },
336 { "sc18is603", sc18is603 },
339 MODULE_DEVICE_TABLE(i2c, sc18is602_id);
341 static struct i2c_driver sc18is602_driver = {
345 .probe = sc18is602_probe,
346 .id_table = sc18is602_id,
349 module_i2c_driver(sc18is602_driver);
351 MODULE_DESCRIPTION("SC18IC602/603 SPI Master Driver");
352 MODULE_AUTHOR("Guenter Roeck");
353 MODULE_LICENSE("GPL");