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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_device.h>
25#include <linux/of.h>
26#include <linux/platform_data/sc18is602.h>
27#include <linux/gpio/consumer.h>
28
29enum chips { sc18is602, sc18is602b, sc18is603 };
30
31#define SC18IS602_BUFSIZ 200
32#define SC18IS602_CLOCK 7372000
33
34#define SC18IS602_MODE_CPHA BIT(2)
35#define SC18IS602_MODE_CPOL BIT(3)
36#define SC18IS602_MODE_LSB_FIRST BIT(5)
37#define SC18IS602_MODE_CLOCK_DIV_4 0x0
38#define SC18IS602_MODE_CLOCK_DIV_16 0x1
39#define SC18IS602_MODE_CLOCK_DIV_64 0x2
40#define SC18IS602_MODE_CLOCK_DIV_128 0x3
41
42struct sc18is602 {
43 struct spi_master *master;
44 struct device *dev;
45 u8 ctrl;
46 u32 freq;
47 u32 speed;
48
49 /* I2C data */
50 struct i2c_client *client;
51 enum chips id;
52 u8 buffer[SC18IS602_BUFSIZ + 1];
53 int tlen; /* Data queued for tx in buffer */
54 int rindex; /* Receive data index in buffer */
55
56 struct gpio_desc *reset;
57};
58
59static int sc18is602_wait_ready(struct sc18is602 *hw, int len)
60{
61 int i, err;
62 int usecs = 1000000 * len / hw->speed + 1;
63 u8 dummy[1];
64
65 for (i = 0; i < 10; i++) {
66 err = i2c_master_recv(hw->client, dummy, 1);
67 if (err >= 0)
68 return 0;
69 usleep_range(usecs, usecs * 2);
70 }
71 return -ETIMEDOUT;
72}
73
74static int sc18is602_txrx(struct sc18is602 *hw, struct spi_message *msg,
75 struct spi_transfer *t, bool do_transfer)
76{
77 unsigned int len = t->len;
78 int ret;
79
80 if (hw->tlen == 0) {
81 /* First byte (I2C command) is chip select */
82 hw->buffer[0] = 1 << msg->spi->chip_select;
83 hw->tlen = 1;
84 hw->rindex = 0;
85 }
86 /*
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.
90 */
91 if (t->tx_buf) {
92 memcpy(&hw->buffer[hw->tlen], t->tx_buf, len);
93 hw->tlen += len;
94 if (t->rx_buf)
95 do_transfer = true;
96 else
97 hw->rindex = hw->tlen - 1;
98 } else if (t->rx_buf) {
99 /*
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
103 * account for CS).
104 */
105 hw->rindex = hw->tlen - 1;
106 memset(&hw->buffer[hw->tlen], 0, len);
107 hw->tlen += len;
108 do_transfer = true;
109 }
110
111 if (do_transfer && hw->tlen > 1) {
112 ret = sc18is602_wait_ready(hw, SC18IS602_BUFSIZ);
113 if (ret < 0)
114 return ret;
115 ret = i2c_master_send(hw->client, hw->buffer, hw->tlen);
116 if (ret < 0)
117 return ret;
118 if (ret != hw->tlen)
119 return -EIO;
120
121 if (t->rx_buf) {
122 int rlen = hw->rindex + len;
123
124 ret = sc18is602_wait_ready(hw, hw->tlen);
125 if (ret < 0)
126 return ret;
127 ret = i2c_master_recv(hw->client, hw->buffer, rlen);
128 if (ret < 0)
129 return ret;
130 if (ret != rlen)
131 return -EIO;
132 memcpy(t->rx_buf, &hw->buffer[hw->rindex], len);
133 }
134 hw->tlen = 0;
135 }
136 return len;
137}
138
139static int sc18is602_setup_transfer(struct sc18is602 *hw, u32 hz, u8 mode)
140{
141 u8 ctrl = 0;
142 int ret;
143
144 if (mode & SPI_CPHA)
145 ctrl |= SC18IS602_MODE_CPHA;
146 if (mode & SPI_CPOL)
147 ctrl |= SC18IS602_MODE_CPOL;
148 if (mode & SPI_LSB_FIRST)
149 ctrl |= SC18IS602_MODE_LSB_FIRST;
150
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;
161 } else {
162 ctrl |= SC18IS602_MODE_CLOCK_DIV_128;
163 hw->speed = hw->freq / 128;
164 }
165
166 /*
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.
170 */
171 if (ctrl == hw->ctrl)
172 return 0;
173
174 ret = i2c_smbus_write_byte_data(hw->client, 0xf0, ctrl);
175 if (ret < 0)
176 return ret;
177
178 hw->ctrl = ctrl;
179
180 return 0;
181}
182
183static int sc18is602_check_transfer(struct spi_device *spi,
184 struct spi_transfer *t, int tlen)
185{
186 if (t && t->len + tlen > SC18IS602_BUFSIZ)
187 return -EINVAL;
188
189 return 0;
190}
191
192static int sc18is602_transfer_one(struct spi_master *master,
193 struct spi_message *m)
194{
195 struct sc18is602 *hw = spi_master_get_devdata(master);
196 struct spi_device *spi = m->spi;
197 struct spi_transfer *t;
198 int status = 0;
199
200 hw->tlen = 0;
201 list_for_each_entry(t, &m->transfers, transfer_list) {
202 bool do_transfer;
203
204 status = sc18is602_check_transfer(spi, t, hw->tlen);
205 if (status < 0)
206 break;
207
208 status = sc18is602_setup_transfer(hw, t->speed_hz, spi->mode);
209 if (status < 0)
210 break;
211
212 do_transfer = t->cs_change || list_is_last(&t->transfer_list,
213 &m->transfers);
214
215 if (t->len) {
216 status = sc18is602_txrx(hw, m, t, do_transfer);
217 if (status < 0)
218 break;
219 m->actual_length += status;
220 }
221 status = 0;
222
223 if (t->delay_usecs)
224 udelay(t->delay_usecs);
225 }
226 m->status = status;
227 spi_finalize_current_message(master);
228
229 return status;
230}
231
232static int sc18is602_setup(struct spi_device *spi)
233{
234 struct sc18is602 *hw = spi_master_get_devdata(spi->master);
235
236 /* SC18IS602 does not support CS2 */
237 if (hw->id == sc18is602 && spi->chip_select == 2)
238 return -ENXIO;
239
240 return 0;
241}
242
243static int sc18is602_probe(struct i2c_client *client,
244 const struct i2c_device_id *id)
245{
246 struct device *dev = &client->dev;
247 struct device_node *np = dev->of_node;
248 struct sc18is602_platform_data *pdata = dev_get_platdata(dev);
249 struct sc18is602 *hw;
250 struct spi_master *master;
251 int error;
252
253 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
254 I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
255 return -EINVAL;
256
257 master = spi_alloc_master(dev, sizeof(struct sc18is602));
258 if (!master)
259 return -ENOMEM;
260
261 hw = spi_master_get_devdata(master);
262 i2c_set_clientdata(client, hw);
263
264 /* assert reset and then release */
265 hw->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
266 if (IS_ERR(hw->reset))
267 return PTR_ERR(hw->reset);
268 gpiod_set_value_cansleep(hw->reset, 0);
269
270 hw->master = master;
271 hw->client = client;
272 hw->dev = dev;
273 hw->ctrl = 0xff;
274
275 if (client->dev.of_node)
276 hw->id = (enum chips)of_device_get_match_data(&client->dev);
277 else
278 hw->id = id->driver_data;
279
280 switch (hw->id) {
281 case sc18is602:
282 case sc18is602b:
283 master->num_chipselect = 4;
284 hw->freq = SC18IS602_CLOCK;
285 break;
286 case sc18is603:
287 master->num_chipselect = 2;
288 if (pdata) {
289 hw->freq = pdata->clock_frequency;
290 } else {
291 const __be32 *val;
292 int len;
293
294 val = of_get_property(np, "clock-frequency", &len);
295 if (val && len >= sizeof(__be32))
296 hw->freq = be32_to_cpup(val);
297 }
298 if (!hw->freq)
299 hw->freq = SC18IS602_CLOCK;
300 break;
301 }
302 master->bus_num = np ? -1 : client->adapter->nr;
303 master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST;
304 master->bits_per_word_mask = SPI_BPW_MASK(8);
305 master->setup = sc18is602_setup;
306 master->transfer_one_message = sc18is602_transfer_one;
307 master->dev.of_node = np;
308 master->min_speed_hz = hw->freq / 128;
309 master->max_speed_hz = hw->freq / 4;
310
311 error = devm_spi_register_master(dev, master);
312 if (error)
313 goto error_reg;
314
315 return 0;
316
317error_reg:
318 spi_master_put(master);
319 return error;
320}
321
322static const struct i2c_device_id sc18is602_id[] = {
323 { "sc18is602", sc18is602 },
324 { "sc18is602b", sc18is602b },
325 { "sc18is603", sc18is603 },
326 { }
327};
328MODULE_DEVICE_TABLE(i2c, sc18is602_id);
329
330static const struct of_device_id sc18is602_of_match[] = {
331 {
332 .compatible = "nxp,sc18is602",
333 .data = (void *)sc18is602
334 },
335 {
336 .compatible = "nxp,sc18is602b",
337 .data = (void *)sc18is602b
338 },
339 {
340 .compatible = "nxp,sc18is603",
341 .data = (void *)sc18is603
342 },
343 { },
344};
345MODULE_DEVICE_TABLE(of, sc18is602_of_match);
346
347static struct i2c_driver sc18is602_driver = {
348 .driver = {
349 .name = "sc18is602",
350 .of_match_table = of_match_ptr(sc18is602_of_match),
351 },
352 .probe = sc18is602_probe,
353 .id_table = sc18is602_id,
354};
355
356module_i2c_driver(sc18is602_driver);
357
358MODULE_DESCRIPTION("SC18IC602/603 SPI Master Driver");
359MODULE_AUTHOR("Guenter Roeck");
360MODULE_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");