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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * NXP SC18IS602/603 SPI driver
4 *
5 * Copyright (C) Guenter Roeck <linux@roeck-us.net>
6 */
7
8#include <linux/kernel.h>
9#include <linux/err.h>
10#include <linux/module.h>
11#include <linux/spi/spi.h>
12#include <linux/i2c.h>
13#include <linux/delay.h>
14#include <linux/pm_runtime.h>
15#include <linux/of.h>
16#include <linux/platform_data/sc18is602.h>
17#include <linux/gpio/consumer.h>
18
19enum chips { sc18is602, sc18is602b, sc18is603 };
20
21#define SC18IS602_BUFSIZ 200
22#define SC18IS602_CLOCK 7372000
23
24#define SC18IS602_MODE_CPHA BIT(2)
25#define SC18IS602_MODE_CPOL BIT(3)
26#define SC18IS602_MODE_LSB_FIRST BIT(5)
27#define SC18IS602_MODE_CLOCK_DIV_4 0x0
28#define SC18IS602_MODE_CLOCK_DIV_16 0x1
29#define SC18IS602_MODE_CLOCK_DIV_64 0x2
30#define SC18IS602_MODE_CLOCK_DIV_128 0x3
31
32struct sc18is602 {
33 struct spi_controller *host;
34 struct device *dev;
35 u8 ctrl;
36 u32 freq;
37 u32 speed;
38
39 /* I2C data */
40 struct i2c_client *client;
41 enum chips id;
42 u8 buffer[SC18IS602_BUFSIZ + 1];
43 int tlen; /* Data queued for tx in buffer */
44 int rindex; /* Receive data index in buffer */
45
46 struct gpio_desc *reset;
47};
48
49static int sc18is602_wait_ready(struct sc18is602 *hw, int len)
50{
51 int i, err;
52 int usecs = 1000000 * len / hw->speed + 1;
53 u8 dummy[1];
54
55 for (i = 0; i < 10; i++) {
56 err = i2c_master_recv(hw->client, dummy, 1);
57 if (err >= 0)
58 return 0;
59 usleep_range(usecs, usecs * 2);
60 }
61 return -ETIMEDOUT;
62}
63
64static int sc18is602_txrx(struct sc18is602 *hw, struct spi_message *msg,
65 struct spi_transfer *t, bool do_transfer)
66{
67 unsigned int len = t->len;
68 int ret;
69
70 if (hw->tlen == 0) {
71 /* First byte (I2C command) is chip select */
72 hw->buffer[0] = 1 << spi_get_chipselect(msg->spi, 0);
73 hw->tlen = 1;
74 hw->rindex = 0;
75 }
76 /*
77 * We can not immediately send data to the chip, since each I2C message
78 * resembles a full SPI message (from CS active to CS inactive).
79 * Enqueue messages up to the first read or until do_transfer is true.
80 */
81 if (t->tx_buf) {
82 memcpy(&hw->buffer[hw->tlen], t->tx_buf, len);
83 hw->tlen += len;
84 if (t->rx_buf)
85 do_transfer = true;
86 else
87 hw->rindex = hw->tlen - 1;
88 } else if (t->rx_buf) {
89 /*
90 * For receive-only transfers we still need to perform a dummy
91 * write to receive data from the SPI chip.
92 * Read data starts at the end of transmit data (minus 1 to
93 * account for CS).
94 */
95 hw->rindex = hw->tlen - 1;
96 memset(&hw->buffer[hw->tlen], 0, len);
97 hw->tlen += len;
98 do_transfer = true;
99 }
100
101 if (do_transfer && hw->tlen > 1) {
102 ret = sc18is602_wait_ready(hw, SC18IS602_BUFSIZ);
103 if (ret < 0)
104 return ret;
105 ret = i2c_master_send(hw->client, hw->buffer, hw->tlen);
106 if (ret < 0)
107 return ret;
108 if (ret != hw->tlen)
109 return -EIO;
110
111 if (t->rx_buf) {
112 int rlen = hw->rindex + len;
113
114 ret = sc18is602_wait_ready(hw, hw->tlen);
115 if (ret < 0)
116 return ret;
117 ret = i2c_master_recv(hw->client, hw->buffer, rlen);
118 if (ret < 0)
119 return ret;
120 if (ret != rlen)
121 return -EIO;
122 memcpy(t->rx_buf, &hw->buffer[hw->rindex], len);
123 }
124 hw->tlen = 0;
125 }
126 return len;
127}
128
129static int sc18is602_setup_transfer(struct sc18is602 *hw, u32 hz, u8 mode)
130{
131 u8 ctrl = 0;
132 int ret;
133
134 if (mode & SPI_CPHA)
135 ctrl |= SC18IS602_MODE_CPHA;
136 if (mode & SPI_CPOL)
137 ctrl |= SC18IS602_MODE_CPOL;
138 if (mode & SPI_LSB_FIRST)
139 ctrl |= SC18IS602_MODE_LSB_FIRST;
140
141 /* Find the closest clock speed */
142 if (hz >= hw->freq / 4) {
143 ctrl |= SC18IS602_MODE_CLOCK_DIV_4;
144 hw->speed = hw->freq / 4;
145 } else if (hz >= hw->freq / 16) {
146 ctrl |= SC18IS602_MODE_CLOCK_DIV_16;
147 hw->speed = hw->freq / 16;
148 } else if (hz >= hw->freq / 64) {
149 ctrl |= SC18IS602_MODE_CLOCK_DIV_64;
150 hw->speed = hw->freq / 64;
151 } else {
152 ctrl |= SC18IS602_MODE_CLOCK_DIV_128;
153 hw->speed = hw->freq / 128;
154 }
155
156 /*
157 * Don't do anything if the control value did not change. The initial
158 * value of 0xff for hw->ctrl ensures that the correct mode will be set
159 * with the first call to this function.
160 */
161 if (ctrl == hw->ctrl)
162 return 0;
163
164 ret = i2c_smbus_write_byte_data(hw->client, 0xf0, ctrl);
165 if (ret < 0)
166 return ret;
167
168 hw->ctrl = ctrl;
169
170 return 0;
171}
172
173static int sc18is602_check_transfer(struct spi_device *spi,
174 struct spi_transfer *t, int tlen)
175{
176 if (t && t->len + tlen > SC18IS602_BUFSIZ + 1)
177 return -EINVAL;
178
179 return 0;
180}
181
182static int sc18is602_transfer_one(struct spi_controller *host,
183 struct spi_message *m)
184{
185 struct sc18is602 *hw = spi_controller_get_devdata(host);
186 struct spi_device *spi = m->spi;
187 struct spi_transfer *t;
188 int status = 0;
189
190 hw->tlen = 0;
191 list_for_each_entry(t, &m->transfers, transfer_list) {
192 bool do_transfer;
193
194 status = sc18is602_check_transfer(spi, t, hw->tlen);
195 if (status < 0)
196 break;
197
198 status = sc18is602_setup_transfer(hw, t->speed_hz, spi->mode);
199 if (status < 0)
200 break;
201
202 do_transfer = t->cs_change || list_is_last(&t->transfer_list,
203 &m->transfers);
204
205 if (t->len) {
206 status = sc18is602_txrx(hw, m, t, do_transfer);
207 if (status < 0)
208 break;
209 m->actual_length += status;
210 }
211 status = 0;
212
213 spi_transfer_delay_exec(t);
214 }
215 m->status = status;
216 spi_finalize_current_message(host);
217
218 return status;
219}
220
221static size_t sc18is602_max_transfer_size(struct spi_device *spi)
222{
223 return SC18IS602_BUFSIZ;
224}
225
226static int sc18is602_setup(struct spi_device *spi)
227{
228 struct sc18is602 *hw = spi_controller_get_devdata(spi->controller);
229
230 /* SC18IS602 does not support CS2 */
231 if (hw->id == sc18is602 && (spi_get_chipselect(spi, 0) == 2))
232 return -ENXIO;
233
234 return 0;
235}
236
237static int sc18is602_probe(struct i2c_client *client)
238{
239 const struct i2c_device_id *id = i2c_client_get_device_id(client);
240 struct device *dev = &client->dev;
241 struct device_node *np = dev->of_node;
242 struct sc18is602_platform_data *pdata = dev_get_platdata(dev);
243 struct sc18is602 *hw;
244 struct spi_controller *host;
245
246 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
247 I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
248 return -EINVAL;
249
250 host = devm_spi_alloc_host(dev, sizeof(struct sc18is602));
251 if (!host)
252 return -ENOMEM;
253
254 hw = spi_controller_get_devdata(host);
255 i2c_set_clientdata(client, hw);
256
257 /* assert reset and then release */
258 hw->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
259 if (IS_ERR(hw->reset))
260 return PTR_ERR(hw->reset);
261 gpiod_set_value_cansleep(hw->reset, 0);
262
263 hw->host = host;
264 hw->client = client;
265 hw->dev = dev;
266 hw->ctrl = 0xff;
267
268 if (client->dev.of_node)
269 hw->id = (uintptr_t)of_device_get_match_data(&client->dev);
270 else
271 hw->id = id->driver_data;
272
273 switch (hw->id) {
274 case sc18is602:
275 case sc18is602b:
276 host->num_chipselect = 4;
277 hw->freq = SC18IS602_CLOCK;
278 break;
279 case sc18is603:
280 host->num_chipselect = 2;
281 if (pdata) {
282 hw->freq = pdata->clock_frequency;
283 } else {
284 const __be32 *val;
285 int len;
286
287 val = of_get_property(np, "clock-frequency", &len);
288 if (val && len >= sizeof(__be32))
289 hw->freq = be32_to_cpup(val);
290 }
291 if (!hw->freq)
292 hw->freq = SC18IS602_CLOCK;
293 break;
294 }
295 host->bus_num = np ? -1 : client->adapter->nr;
296 host->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST;
297 host->bits_per_word_mask = SPI_BPW_MASK(8);
298 host->setup = sc18is602_setup;
299 host->transfer_one_message = sc18is602_transfer_one;
300 host->max_transfer_size = sc18is602_max_transfer_size;
301 host->max_message_size = sc18is602_max_transfer_size;
302 host->dev.of_node = np;
303 host->min_speed_hz = hw->freq / 128;
304 host->max_speed_hz = hw->freq / 4;
305
306 return devm_spi_register_controller(dev, host);
307}
308
309static const struct i2c_device_id sc18is602_id[] = {
310 { "sc18is602", sc18is602 },
311 { "sc18is602b", sc18is602b },
312 { "sc18is603", sc18is603 },
313 { }
314};
315MODULE_DEVICE_TABLE(i2c, sc18is602_id);
316
317static const struct of_device_id sc18is602_of_match[] __maybe_unused = {
318 {
319 .compatible = "nxp,sc18is602",
320 .data = (void *)sc18is602
321 },
322 {
323 .compatible = "nxp,sc18is602b",
324 .data = (void *)sc18is602b
325 },
326 {
327 .compatible = "nxp,sc18is603",
328 .data = (void *)sc18is603
329 },
330 { },
331};
332MODULE_DEVICE_TABLE(of, sc18is602_of_match);
333
334static struct i2c_driver sc18is602_driver = {
335 .driver = {
336 .name = "sc18is602",
337 .of_match_table = of_match_ptr(sc18is602_of_match),
338 },
339 .probe = sc18is602_probe,
340 .id_table = sc18is602_id,
341};
342
343module_i2c_driver(sc18is602_driver);
344
345MODULE_DESCRIPTION("SC18IS602/603 SPI Host Driver");
346MODULE_AUTHOR("Guenter Roeck");
347MODULE_LICENSE("GPL");
1/*
2 * NXP SC18IS602/603 SPI driver
3 *
4 * Copyright (C) Guenter Roeck <linux@roeck-us.net>
5 *
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.
10 *
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.
15 */
16
17#include <linux/kernel.h>
18#include <linux/err.h>
19#include <linux/module.h>
20#include <linux/spi/spi.h>
21#include <linux/i2c.h>
22#include <linux/delay.h>
23#include <linux/pm_runtime.h>
24#include <linux/of.h>
25#include <linux/platform_data/sc18is602.h>
26
27enum chips { sc18is602, sc18is602b, sc18is603 };
28
29#define SC18IS602_BUFSIZ 200
30#define SC18IS602_CLOCK 7372000
31
32#define SC18IS602_MODE_CPHA BIT(2)
33#define SC18IS602_MODE_CPOL BIT(3)
34#define SC18IS602_MODE_LSB_FIRST BIT(5)
35#define SC18IS602_MODE_CLOCK_DIV_4 0x0
36#define SC18IS602_MODE_CLOCK_DIV_16 0x1
37#define SC18IS602_MODE_CLOCK_DIV_64 0x2
38#define SC18IS602_MODE_CLOCK_DIV_128 0x3
39
40struct sc18is602 {
41 struct spi_master *master;
42 struct device *dev;
43 u8 ctrl;
44 u32 freq;
45 u32 speed;
46
47 /* I2C data */
48 struct i2c_client *client;
49 enum chips id;
50 u8 buffer[SC18IS602_BUFSIZ + 1];
51 int tlen; /* Data queued for tx in buffer */
52 int rindex; /* Receive data index in buffer */
53};
54
55static int sc18is602_wait_ready(struct sc18is602 *hw, int len)
56{
57 int i, err;
58 int usecs = 1000000 * len / hw->speed + 1;
59 u8 dummy[1];
60
61 for (i = 0; i < 10; i++) {
62 err = i2c_master_recv(hw->client, dummy, 1);
63 if (err >= 0)
64 return 0;
65 usleep_range(usecs, usecs * 2);
66 }
67 return -ETIMEDOUT;
68}
69
70static int sc18is602_txrx(struct sc18is602 *hw, struct spi_message *msg,
71 struct spi_transfer *t, bool do_transfer)
72{
73 unsigned int len = t->len;
74 int ret;
75
76 if (hw->tlen == 0) {
77 /* First byte (I2C command) is chip select */
78 hw->buffer[0] = 1 << msg->spi->chip_select;
79 hw->tlen = 1;
80 hw->rindex = 0;
81 }
82 /*
83 * We can not immediately send data to the chip, since each I2C message
84 * resembles a full SPI message (from CS active to CS inactive).
85 * Enqueue messages up to the first read or until do_transfer is true.
86 */
87 if (t->tx_buf) {
88 memcpy(&hw->buffer[hw->tlen], t->tx_buf, len);
89 hw->tlen += len;
90 if (t->rx_buf)
91 do_transfer = true;
92 else
93 hw->rindex = hw->tlen - 1;
94 } else if (t->rx_buf) {
95 /*
96 * For receive-only transfers we still need to perform a dummy
97 * write to receive data from the SPI chip.
98 * Read data starts at the end of transmit data (minus 1 to
99 * account for CS).
100 */
101 hw->rindex = hw->tlen - 1;
102 memset(&hw->buffer[hw->tlen], 0, len);
103 hw->tlen += len;
104 do_transfer = true;
105 }
106
107 if (do_transfer && hw->tlen > 1) {
108 ret = sc18is602_wait_ready(hw, SC18IS602_BUFSIZ);
109 if (ret < 0)
110 return ret;
111 ret = i2c_master_send(hw->client, hw->buffer, hw->tlen);
112 if (ret < 0)
113 return ret;
114 if (ret != hw->tlen)
115 return -EIO;
116
117 if (t->rx_buf) {
118 int rlen = hw->rindex + len;
119
120 ret = sc18is602_wait_ready(hw, hw->tlen);
121 if (ret < 0)
122 return ret;
123 ret = i2c_master_recv(hw->client, hw->buffer, rlen);
124 if (ret < 0)
125 return ret;
126 if (ret != rlen)
127 return -EIO;
128 memcpy(t->rx_buf, &hw->buffer[hw->rindex], len);
129 }
130 hw->tlen = 0;
131 }
132 return len;
133}
134
135static int sc18is602_setup_transfer(struct sc18is602 *hw, u32 hz, u8 mode)
136{
137 u8 ctrl = 0;
138 int ret;
139
140 if (mode & SPI_CPHA)
141 ctrl |= SC18IS602_MODE_CPHA;
142 if (mode & SPI_CPOL)
143 ctrl |= SC18IS602_MODE_CPOL;
144 if (mode & SPI_LSB_FIRST)
145 ctrl |= SC18IS602_MODE_LSB_FIRST;
146
147 /* Find the closest clock speed */
148 if (hz >= hw->freq / 4) {
149 ctrl |= SC18IS602_MODE_CLOCK_DIV_4;
150 hw->speed = hw->freq / 4;
151 } else if (hz >= hw->freq / 16) {
152 ctrl |= SC18IS602_MODE_CLOCK_DIV_16;
153 hw->speed = hw->freq / 16;
154 } else if (hz >= hw->freq / 64) {
155 ctrl |= SC18IS602_MODE_CLOCK_DIV_64;
156 hw->speed = hw->freq / 64;
157 } else {
158 ctrl |= SC18IS602_MODE_CLOCK_DIV_128;
159 hw->speed = hw->freq / 128;
160 }
161
162 /*
163 * Don't do anything if the control value did not change. The initial
164 * value of 0xff for hw->ctrl ensures that the correct mode will be set
165 * with the first call to this function.
166 */
167 if (ctrl == hw->ctrl)
168 return 0;
169
170 ret = i2c_smbus_write_byte_data(hw->client, 0xf0, ctrl);
171 if (ret < 0)
172 return ret;
173
174 hw->ctrl = ctrl;
175
176 return 0;
177}
178
179static int sc18is602_check_transfer(struct spi_device *spi,
180 struct spi_transfer *t, int tlen)
181{
182 if (t && t->len + tlen > SC18IS602_BUFSIZ)
183 return -EINVAL;
184
185 return 0;
186}
187
188static int sc18is602_transfer_one(struct spi_master *master,
189 struct spi_message *m)
190{
191 struct sc18is602 *hw = spi_master_get_devdata(master);
192 struct spi_device *spi = m->spi;
193 struct spi_transfer *t;
194 int status = 0;
195
196 hw->tlen = 0;
197 list_for_each_entry(t, &m->transfers, transfer_list) {
198 bool do_transfer;
199
200 status = sc18is602_check_transfer(spi, t, hw->tlen);
201 if (status < 0)
202 break;
203
204 status = sc18is602_setup_transfer(hw, t->speed_hz, spi->mode);
205 if (status < 0)
206 break;
207
208 do_transfer = t->cs_change || list_is_last(&t->transfer_list,
209 &m->transfers);
210
211 if (t->len) {
212 status = sc18is602_txrx(hw, m, t, do_transfer);
213 if (status < 0)
214 break;
215 m->actual_length += status;
216 }
217 status = 0;
218
219 if (t->delay_usecs)
220 udelay(t->delay_usecs);
221 }
222 m->status = status;
223 spi_finalize_current_message(master);
224
225 return status;
226}
227
228static int sc18is602_setup(struct spi_device *spi)
229{
230 struct sc18is602 *hw = spi_master_get_devdata(spi->master);
231
232 /* SC18IS602 does not support CS2 */
233 if (hw->id == sc18is602 && spi->chip_select == 2)
234 return -ENXIO;
235
236 return 0;
237}
238
239static int sc18is602_probe(struct i2c_client *client,
240 const struct i2c_device_id *id)
241{
242 struct device *dev = &client->dev;
243 struct device_node *np = dev->of_node;
244 struct sc18is602_platform_data *pdata = dev_get_platdata(dev);
245 struct sc18is602 *hw;
246 struct spi_master *master;
247 int error;
248
249 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
250 I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
251 return -EINVAL;
252
253 master = spi_alloc_master(dev, sizeof(struct sc18is602));
254 if (!master)
255 return -ENOMEM;
256
257 hw = spi_master_get_devdata(master);
258 i2c_set_clientdata(client, hw);
259
260 hw->master = master;
261 hw->client = client;
262 hw->dev = dev;
263 hw->ctrl = 0xff;
264
265 hw->id = id->driver_data;
266
267 switch (hw->id) {
268 case sc18is602:
269 case sc18is602b:
270 master->num_chipselect = 4;
271 hw->freq = SC18IS602_CLOCK;
272 break;
273 case sc18is603:
274 master->num_chipselect = 2;
275 if (pdata) {
276 hw->freq = pdata->clock_frequency;
277 } else {
278 const __be32 *val;
279 int len;
280
281 val = of_get_property(np, "clock-frequency", &len);
282 if (val && len >= sizeof(__be32))
283 hw->freq = be32_to_cpup(val);
284 }
285 if (!hw->freq)
286 hw->freq = SC18IS602_CLOCK;
287 break;
288 }
289 master->bus_num = np ? -1 : client->adapter->nr;
290 master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST;
291 master->bits_per_word_mask = SPI_BPW_MASK(8);
292 master->setup = sc18is602_setup;
293 master->transfer_one_message = sc18is602_transfer_one;
294 master->dev.of_node = np;
295 master->min_speed_hz = hw->freq / 128;
296 master->max_speed_hz = hw->freq / 4;
297
298 error = devm_spi_register_master(dev, master);
299 if (error)
300 goto error_reg;
301
302 return 0;
303
304error_reg:
305 spi_master_put(master);
306 return error;
307}
308
309static const struct i2c_device_id sc18is602_id[] = {
310 { "sc18is602", sc18is602 },
311 { "sc18is602b", sc18is602b },
312 { "sc18is603", sc18is603 },
313 { }
314};
315MODULE_DEVICE_TABLE(i2c, sc18is602_id);
316
317static struct i2c_driver sc18is602_driver = {
318 .driver = {
319 .name = "sc18is602",
320 },
321 .probe = sc18is602_probe,
322 .id_table = sc18is602_id,
323};
324
325module_i2c_driver(sc18is602_driver);
326
327MODULE_DESCRIPTION("SC18IC602/603 SPI Master Driver");
328MODULE_AUTHOR("Guenter Roeck");
329MODULE_LICENSE("GPL");