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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * NBUS driver for TS-4600 based boards
4 *
5 * Copyright (c) 2016 - Savoir-faire Linux
6 * Author: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
7 *
8 * This driver implements a GPIOs bit-banged bus, called the NBUS by Technologic
9 * Systems. It is used to communicate with the peripherals in the FPGA on the
10 * TS-4600 SoM.
11 */
12
13#include <linux/bitops.h>
14#include <linux/gpio/consumer.h>
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/mutex.h>
18#include <linux/of_platform.h>
19#include <linux/platform_device.h>
20#include <linux/pwm.h>
21#include <linux/ts-nbus.h>
22
23#define TS_NBUS_DIRECTION_IN 0
24#define TS_NBUS_DIRECTION_OUT 1
25#define TS_NBUS_WRITE_ADR 0
26#define TS_NBUS_WRITE_VAL 1
27
28struct ts_nbus {
29 struct pwm_device *pwm;
30 struct gpio_descs *data;
31 struct gpio_desc *csn;
32 struct gpio_desc *txrx;
33 struct gpio_desc *strobe;
34 struct gpio_desc *ale;
35 struct gpio_desc *rdy;
36 struct mutex lock;
37};
38
39/*
40 * request all gpios required by the bus.
41 */
42static int ts_nbus_init_pdata(struct platform_device *pdev,
43 struct ts_nbus *ts_nbus)
44{
45 ts_nbus->data = devm_gpiod_get_array(&pdev->dev, "ts,data",
46 GPIOD_OUT_HIGH);
47 if (IS_ERR(ts_nbus->data))
48 return dev_err_probe(&pdev->dev, PTR_ERR(ts_nbus->data),
49 "failed to retrieve ts,data-gpio from dts\n");
50
51 ts_nbus->csn = devm_gpiod_get(&pdev->dev, "ts,csn", GPIOD_OUT_HIGH);
52 if (IS_ERR(ts_nbus->csn))
53 return dev_err_probe(&pdev->dev, PTR_ERR(ts_nbus->csn),
54 "failed to retrieve ts,csn-gpio from dts\n");
55
56 ts_nbus->txrx = devm_gpiod_get(&pdev->dev, "ts,txrx", GPIOD_OUT_HIGH);
57 if (IS_ERR(ts_nbus->txrx))
58 return dev_err_probe(&pdev->dev, PTR_ERR(ts_nbus->txrx),
59 "failed to retrieve ts,txrx-gpio from dts\n");
60
61 ts_nbus->strobe = devm_gpiod_get(&pdev->dev, "ts,strobe", GPIOD_OUT_HIGH);
62 if (IS_ERR(ts_nbus->strobe))
63 return dev_err_probe(&pdev->dev, PTR_ERR(ts_nbus->strobe),
64 "failed to retrieve ts,strobe-gpio from dts\n");
65
66 ts_nbus->ale = devm_gpiod_get(&pdev->dev, "ts,ale", GPIOD_OUT_HIGH);
67 if (IS_ERR(ts_nbus->ale))
68 return dev_err_probe(&pdev->dev, PTR_ERR(ts_nbus->ale),
69 "failed to retrieve ts,ale-gpio from dts\n");
70
71 ts_nbus->rdy = devm_gpiod_get(&pdev->dev, "ts,rdy", GPIOD_IN);
72 if (IS_ERR(ts_nbus->rdy))
73 return dev_err_probe(&pdev->dev, PTR_ERR(ts_nbus->rdy),
74 "failed to retrieve ts,rdy-gpio from dts\n");
75
76 return 0;
77}
78
79/*
80 * the data gpios are used for reading and writing values, their directions
81 * should be adjusted accordingly.
82 */
83static void ts_nbus_set_direction(struct ts_nbus *ts_nbus, int direction)
84{
85 int i;
86
87 for (i = 0; i < 8; i++) {
88 if (direction == TS_NBUS_DIRECTION_IN)
89 gpiod_direction_input(ts_nbus->data->desc[i]);
90 else
91 /* when used as output the default state of the data
92 * lines are set to high */
93 gpiod_direction_output(ts_nbus->data->desc[i], 1);
94 }
95}
96
97/*
98 * reset the bus in its initial state.
99 * The data, csn, strobe and ale lines must be zero'ed to let the FPGA knows a
100 * new transaction can be process.
101 */
102static void ts_nbus_reset_bus(struct ts_nbus *ts_nbus)
103{
104 DECLARE_BITMAP(values, 8);
105
106 values[0] = 0;
107
108 gpiod_set_array_value_cansleep(8, ts_nbus->data->desc,
109 ts_nbus->data->info, values);
110 gpiod_set_value_cansleep(ts_nbus->csn, 0);
111 gpiod_set_value_cansleep(ts_nbus->strobe, 0);
112 gpiod_set_value_cansleep(ts_nbus->ale, 0);
113}
114
115/*
116 * let the FPGA knows it can process.
117 */
118static void ts_nbus_start_transaction(struct ts_nbus *ts_nbus)
119{
120 gpiod_set_value_cansleep(ts_nbus->strobe, 1);
121}
122
123/*
124 * read a byte value from the data gpios.
125 * return 0 on success or negative errno on failure.
126 */
127static int ts_nbus_read_byte(struct ts_nbus *ts_nbus, u8 *val)
128{
129 struct gpio_descs *gpios = ts_nbus->data;
130 int ret, i;
131
132 *val = 0;
133 for (i = 0; i < 8; i++) {
134 ret = gpiod_get_value_cansleep(gpios->desc[i]);
135 if (ret < 0)
136 return ret;
137 if (ret)
138 *val |= BIT(i);
139 }
140
141 return 0;
142}
143
144/*
145 * set the data gpios accordingly to the byte value.
146 */
147static void ts_nbus_write_byte(struct ts_nbus *ts_nbus, u8 byte)
148{
149 struct gpio_descs *gpios = ts_nbus->data;
150 DECLARE_BITMAP(values, 8);
151
152 values[0] = byte;
153
154 gpiod_set_array_value_cansleep(8, gpios->desc, gpios->info, values);
155}
156
157/*
158 * reading the bus consists of resetting the bus, then notifying the FPGA to
159 * send the data in the data gpios and return the read value.
160 * return 0 on success or negative errno on failure.
161 */
162static int ts_nbus_read_bus(struct ts_nbus *ts_nbus, u8 *val)
163{
164 ts_nbus_reset_bus(ts_nbus);
165 ts_nbus_start_transaction(ts_nbus);
166
167 return ts_nbus_read_byte(ts_nbus, val);
168}
169
170/*
171 * writing to the bus consists of resetting the bus, then define the type of
172 * command (address/value), write the data and notify the FPGA to retrieve the
173 * value in the data gpios.
174 */
175static void ts_nbus_write_bus(struct ts_nbus *ts_nbus, int cmd, u8 val)
176{
177 ts_nbus_reset_bus(ts_nbus);
178
179 if (cmd == TS_NBUS_WRITE_ADR)
180 gpiod_set_value_cansleep(ts_nbus->ale, 1);
181
182 ts_nbus_write_byte(ts_nbus, val);
183 ts_nbus_start_transaction(ts_nbus);
184}
185
186/*
187 * read the value in the FPGA register at the given address.
188 * return 0 on success or negative errno on failure.
189 */
190int ts_nbus_read(struct ts_nbus *ts_nbus, u8 adr, u16 *val)
191{
192 int ret, i;
193 u8 byte;
194
195 /* bus access must be atomic */
196 mutex_lock(&ts_nbus->lock);
197
198 /* set the bus in read mode */
199 gpiod_set_value_cansleep(ts_nbus->txrx, 0);
200
201 /* write address */
202 ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_ADR, adr);
203
204 /* set the data gpios direction as input before reading */
205 ts_nbus_set_direction(ts_nbus, TS_NBUS_DIRECTION_IN);
206
207 /* reading value MSB first */
208 do {
209 *val = 0;
210 byte = 0;
211 for (i = 1; i >= 0; i--) {
212 /* read a byte from the bus, leave on error */
213 ret = ts_nbus_read_bus(ts_nbus, &byte);
214 if (ret < 0)
215 goto err;
216
217 /* append the byte read to the final value */
218 *val |= byte << (i * 8);
219 }
220 gpiod_set_value_cansleep(ts_nbus->csn, 1);
221 ret = gpiod_get_value_cansleep(ts_nbus->rdy);
222 } while (ret);
223
224err:
225 /* restore the data gpios direction as output after reading */
226 ts_nbus_set_direction(ts_nbus, TS_NBUS_DIRECTION_OUT);
227
228 mutex_unlock(&ts_nbus->lock);
229
230 return ret;
231}
232EXPORT_SYMBOL_GPL(ts_nbus_read);
233
234/*
235 * write the desired value in the FPGA register at the given address.
236 */
237int ts_nbus_write(struct ts_nbus *ts_nbus, u8 adr, u16 val)
238{
239 int i;
240
241 /* bus access must be atomic */
242 mutex_lock(&ts_nbus->lock);
243
244 /* set the bus in write mode */
245 gpiod_set_value_cansleep(ts_nbus->txrx, 1);
246
247 /* write address */
248 ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_ADR, adr);
249
250 /* writing value MSB first */
251 for (i = 1; i >= 0; i--)
252 ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_VAL, (u8)(val >> (i * 8)));
253
254 /* wait for completion */
255 gpiod_set_value_cansleep(ts_nbus->csn, 1);
256 while (gpiod_get_value_cansleep(ts_nbus->rdy) != 0) {
257 gpiod_set_value_cansleep(ts_nbus->csn, 0);
258 gpiod_set_value_cansleep(ts_nbus->csn, 1);
259 }
260
261 mutex_unlock(&ts_nbus->lock);
262
263 return 0;
264}
265EXPORT_SYMBOL_GPL(ts_nbus_write);
266
267static int ts_nbus_probe(struct platform_device *pdev)
268{
269 struct pwm_device *pwm;
270 struct pwm_state state;
271 struct device *dev = &pdev->dev;
272 struct ts_nbus *ts_nbus;
273 int ret;
274
275 ts_nbus = devm_kzalloc(dev, sizeof(*ts_nbus), GFP_KERNEL);
276 if (!ts_nbus)
277 return -ENOMEM;
278
279 mutex_init(&ts_nbus->lock);
280
281 ret = ts_nbus_init_pdata(pdev, ts_nbus);
282 if (ret < 0)
283 return ret;
284
285 pwm = devm_pwm_get(dev, NULL);
286 if (IS_ERR(pwm))
287 return dev_err_probe(dev, PTR_ERR(pwm),
288 "unable to request PWM\n");
289
290 pwm_init_state(pwm, &state);
291 if (!state.period)
292 return dev_err_probe(dev, -EINVAL, "invalid PWM period\n");
293
294 state.duty_cycle = state.period;
295 state.enabled = true;
296
297 ret = pwm_apply_might_sleep(pwm, &state);
298 if (ret < 0)
299 return dev_err_probe(dev, ret, "failed to configure PWM\n");
300
301 /*
302 * we can now start the FPGA and populate the peripherals.
303 */
304 ts_nbus->pwm = pwm;
305
306 /*
307 * let the child nodes retrieve this instance of the ts-nbus.
308 */
309 dev_set_drvdata(dev, ts_nbus);
310
311 ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
312 if (ret < 0)
313 return dev_err_probe(dev, ret,
314 "failed to populate platform devices on bus\n");
315
316 dev_info(dev, "initialized\n");
317
318 return 0;
319}
320
321static void ts_nbus_remove(struct platform_device *pdev)
322{
323 struct ts_nbus *ts_nbus = dev_get_drvdata(&pdev->dev);
324
325 /* shutdown the FPGA */
326 mutex_lock(&ts_nbus->lock);
327 pwm_disable(ts_nbus->pwm);
328 mutex_unlock(&ts_nbus->lock);
329}
330
331static const struct of_device_id ts_nbus_of_match[] = {
332 { .compatible = "technologic,ts-nbus", },
333 { },
334};
335MODULE_DEVICE_TABLE(of, ts_nbus_of_match);
336
337static struct platform_driver ts_nbus_driver = {
338 .probe = ts_nbus_probe,
339 .remove = ts_nbus_remove,
340 .driver = {
341 .name = "ts_nbus",
342 .of_match_table = ts_nbus_of_match,
343 },
344};
345
346module_platform_driver(ts_nbus_driver);
347
348MODULE_ALIAS("platform:ts_nbus");
349MODULE_AUTHOR("Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>");
350MODULE_DESCRIPTION("Technologic Systems NBUS");
351MODULE_LICENSE("GPL v2");
1/*
2 * NBUS driver for TS-4600 based boards
3 *
4 * Copyright (c) 2016 - Savoir-faire Linux
5 * Author: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>
6 *
7 * This file is licensed under the terms of the GNU General Public
8 * License version 2. This program is licensed "as is" without any
9 * warranty of any kind, whether express or implied.
10 *
11 * This driver implements a GPIOs bit-banged bus, called the NBUS by Technologic
12 * Systems. It is used to communicate with the peripherals in the FPGA on the
13 * TS-4600 SoM.
14 */
15
16#include <linux/bitops.h>
17#include <linux/gpio/consumer.h>
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/mutex.h>
21#include <linux/of_platform.h>
22#include <linux/platform_device.h>
23#include <linux/pwm.h>
24#include <linux/ts-nbus.h>
25
26#define TS_NBUS_DIRECTION_IN 0
27#define TS_NBUS_DIRECTION_OUT 1
28#define TS_NBUS_WRITE_ADR 0
29#define TS_NBUS_WRITE_VAL 1
30
31struct ts_nbus {
32 struct pwm_device *pwm;
33 struct gpio_descs *data;
34 struct gpio_desc *csn;
35 struct gpio_desc *txrx;
36 struct gpio_desc *strobe;
37 struct gpio_desc *ale;
38 struct gpio_desc *rdy;
39 struct mutex lock;
40};
41
42/*
43 * request all gpios required by the bus.
44 */
45static int ts_nbus_init_pdata(struct platform_device *pdev, struct ts_nbus
46 *ts_nbus)
47{
48 ts_nbus->data = devm_gpiod_get_array(&pdev->dev, "ts,data",
49 GPIOD_OUT_HIGH);
50 if (IS_ERR(ts_nbus->data)) {
51 dev_err(&pdev->dev, "failed to retrieve ts,data-gpio from dts\n");
52 return PTR_ERR(ts_nbus->data);
53 }
54
55 ts_nbus->csn = devm_gpiod_get(&pdev->dev, "ts,csn", GPIOD_OUT_HIGH);
56 if (IS_ERR(ts_nbus->csn)) {
57 dev_err(&pdev->dev, "failed to retrieve ts,csn-gpio from dts\n");
58 return PTR_ERR(ts_nbus->csn);
59 }
60
61 ts_nbus->txrx = devm_gpiod_get(&pdev->dev, "ts,txrx", GPIOD_OUT_HIGH);
62 if (IS_ERR(ts_nbus->txrx)) {
63 dev_err(&pdev->dev, "failed to retrieve ts,txrx-gpio from dts\n");
64 return PTR_ERR(ts_nbus->txrx);
65 }
66
67 ts_nbus->strobe = devm_gpiod_get(&pdev->dev, "ts,strobe", GPIOD_OUT_HIGH);
68 if (IS_ERR(ts_nbus->strobe)) {
69 dev_err(&pdev->dev, "failed to retrieve ts,strobe-gpio from dts\n");
70 return PTR_ERR(ts_nbus->strobe);
71 }
72
73 ts_nbus->ale = devm_gpiod_get(&pdev->dev, "ts,ale", GPIOD_OUT_HIGH);
74 if (IS_ERR(ts_nbus->ale)) {
75 dev_err(&pdev->dev, "failed to retrieve ts,ale-gpio from dts\n");
76 return PTR_ERR(ts_nbus->ale);
77 }
78
79 ts_nbus->rdy = devm_gpiod_get(&pdev->dev, "ts,rdy", GPIOD_IN);
80 if (IS_ERR(ts_nbus->rdy)) {
81 dev_err(&pdev->dev, "failed to retrieve ts,rdy-gpio from dts\n");
82 return PTR_ERR(ts_nbus->rdy);
83 }
84
85 return 0;
86}
87
88/*
89 * the data gpios are used for reading and writing values, their directions
90 * should be adjusted accordingly.
91 */
92static void ts_nbus_set_direction(struct ts_nbus *ts_nbus, int direction)
93{
94 int i;
95
96 for (i = 0; i < 8; i++) {
97 if (direction == TS_NBUS_DIRECTION_IN)
98 gpiod_direction_input(ts_nbus->data->desc[i]);
99 else
100 /* when used as output the default state of the data
101 * lines are set to high */
102 gpiod_direction_output(ts_nbus->data->desc[i], 1);
103 }
104}
105
106/*
107 * reset the bus in its initial state.
108 * The data, csn, strobe and ale lines must be zero'ed to let the FPGA knows a
109 * new transaction can be process.
110 */
111static void ts_nbus_reset_bus(struct ts_nbus *ts_nbus)
112{
113 int i;
114 int values[8];
115
116 for (i = 0; i < 8; i++)
117 values[i] = 0;
118
119 gpiod_set_array_value_cansleep(8, ts_nbus->data->desc, values);
120 gpiod_set_value_cansleep(ts_nbus->csn, 0);
121 gpiod_set_value_cansleep(ts_nbus->strobe, 0);
122 gpiod_set_value_cansleep(ts_nbus->ale, 0);
123}
124
125/*
126 * let the FPGA knows it can process.
127 */
128static void ts_nbus_start_transaction(struct ts_nbus *ts_nbus)
129{
130 gpiod_set_value_cansleep(ts_nbus->strobe, 1);
131}
132
133/*
134 * read a byte value from the data gpios.
135 * return 0 on success or negative errno on failure.
136 */
137static int ts_nbus_read_byte(struct ts_nbus *ts_nbus, u8 *val)
138{
139 struct gpio_descs *gpios = ts_nbus->data;
140 int ret, i;
141
142 *val = 0;
143 for (i = 0; i < 8; i++) {
144 ret = gpiod_get_value_cansleep(gpios->desc[i]);
145 if (ret < 0)
146 return ret;
147 if (ret)
148 *val |= BIT(i);
149 }
150
151 return 0;
152}
153
154/*
155 * set the data gpios accordingly to the byte value.
156 */
157static void ts_nbus_write_byte(struct ts_nbus *ts_nbus, u8 byte)
158{
159 struct gpio_descs *gpios = ts_nbus->data;
160 int i;
161 int values[8];
162
163 for (i = 0; i < 8; i++)
164 if (byte & BIT(i))
165 values[i] = 1;
166 else
167 values[i] = 0;
168
169 gpiod_set_array_value_cansleep(8, gpios->desc, values);
170}
171
172/*
173 * reading the bus consists of resetting the bus, then notifying the FPGA to
174 * send the data in the data gpios and return the read value.
175 * return 0 on success or negative errno on failure.
176 */
177static int ts_nbus_read_bus(struct ts_nbus *ts_nbus, u8 *val)
178{
179 ts_nbus_reset_bus(ts_nbus);
180 ts_nbus_start_transaction(ts_nbus);
181
182 return ts_nbus_read_byte(ts_nbus, val);
183}
184
185/*
186 * writing to the bus consists of resetting the bus, then define the type of
187 * command (address/value), write the data and notify the FPGA to retrieve the
188 * value in the data gpios.
189 */
190static void ts_nbus_write_bus(struct ts_nbus *ts_nbus, int cmd, u8 val)
191{
192 ts_nbus_reset_bus(ts_nbus);
193
194 if (cmd == TS_NBUS_WRITE_ADR)
195 gpiod_set_value_cansleep(ts_nbus->ale, 1);
196
197 ts_nbus_write_byte(ts_nbus, val);
198 ts_nbus_start_transaction(ts_nbus);
199}
200
201/*
202 * read the value in the FPGA register at the given address.
203 * return 0 on success or negative errno on failure.
204 */
205int ts_nbus_read(struct ts_nbus *ts_nbus, u8 adr, u16 *val)
206{
207 int ret, i;
208 u8 byte;
209
210 /* bus access must be atomic */
211 mutex_lock(&ts_nbus->lock);
212
213 /* set the bus in read mode */
214 gpiod_set_value_cansleep(ts_nbus->txrx, 0);
215
216 /* write address */
217 ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_ADR, adr);
218
219 /* set the data gpios direction as input before reading */
220 ts_nbus_set_direction(ts_nbus, TS_NBUS_DIRECTION_IN);
221
222 /* reading value MSB first */
223 do {
224 *val = 0;
225 byte = 0;
226 for (i = 1; i >= 0; i--) {
227 /* read a byte from the bus, leave on error */
228 ret = ts_nbus_read_bus(ts_nbus, &byte);
229 if (ret < 0)
230 goto err;
231
232 /* append the byte read to the final value */
233 *val |= byte << (i * 8);
234 }
235 gpiod_set_value_cansleep(ts_nbus->csn, 1);
236 ret = gpiod_get_value_cansleep(ts_nbus->rdy);
237 } while (ret);
238
239err:
240 /* restore the data gpios direction as output after reading */
241 ts_nbus_set_direction(ts_nbus, TS_NBUS_DIRECTION_OUT);
242
243 mutex_unlock(&ts_nbus->lock);
244
245 return ret;
246}
247EXPORT_SYMBOL_GPL(ts_nbus_read);
248
249/*
250 * write the desired value in the FPGA register at the given address.
251 */
252int ts_nbus_write(struct ts_nbus *ts_nbus, u8 adr, u16 val)
253{
254 int i;
255
256 /* bus access must be atomic */
257 mutex_lock(&ts_nbus->lock);
258
259 /* set the bus in write mode */
260 gpiod_set_value_cansleep(ts_nbus->txrx, 1);
261
262 /* write address */
263 ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_ADR, adr);
264
265 /* writing value MSB first */
266 for (i = 1; i >= 0; i--)
267 ts_nbus_write_bus(ts_nbus, TS_NBUS_WRITE_VAL, (u8)(val >> (i * 8)));
268
269 /* wait for completion */
270 gpiod_set_value_cansleep(ts_nbus->csn, 1);
271 while (gpiod_get_value_cansleep(ts_nbus->rdy) != 0) {
272 gpiod_set_value_cansleep(ts_nbus->csn, 0);
273 gpiod_set_value_cansleep(ts_nbus->csn, 1);
274 }
275
276 mutex_unlock(&ts_nbus->lock);
277
278 return 0;
279}
280EXPORT_SYMBOL_GPL(ts_nbus_write);
281
282static int ts_nbus_probe(struct platform_device *pdev)
283{
284 struct pwm_device *pwm;
285 struct pwm_args pargs;
286 struct device *dev = &pdev->dev;
287 struct ts_nbus *ts_nbus;
288 int ret;
289
290 ts_nbus = devm_kzalloc(dev, sizeof(*ts_nbus), GFP_KERNEL);
291 if (!ts_nbus)
292 return -ENOMEM;
293
294 mutex_init(&ts_nbus->lock);
295
296 ret = ts_nbus_init_pdata(pdev, ts_nbus);
297 if (ret < 0)
298 return ret;
299
300 pwm = devm_pwm_get(dev, NULL);
301 if (IS_ERR(pwm)) {
302 ret = PTR_ERR(pwm);
303 if (ret != -EPROBE_DEFER)
304 dev_err(dev, "unable to request PWM\n");
305 return ret;
306 }
307
308 pwm_get_args(pwm, &pargs);
309 if (!pargs.period) {
310 dev_err(&pdev->dev, "invalid PWM period\n");
311 return -EINVAL;
312 }
313
314 /*
315 * FIXME: pwm_apply_args() should be removed when switching to
316 * the atomic PWM API.
317 */
318 pwm_apply_args(pwm);
319 ret = pwm_config(pwm, pargs.period, pargs.period);
320 if (ret < 0)
321 return ret;
322
323 /*
324 * we can now start the FPGA and populate the peripherals.
325 */
326 pwm_enable(pwm);
327 ts_nbus->pwm = pwm;
328
329 /*
330 * let the child nodes retrieve this instance of the ts-nbus.
331 */
332 dev_set_drvdata(dev, ts_nbus);
333
334 ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
335 if (ret < 0)
336 return ret;
337
338 dev_info(dev, "initialized\n");
339
340 return 0;
341}
342
343static int ts_nbus_remove(struct platform_device *pdev)
344{
345 struct ts_nbus *ts_nbus = dev_get_drvdata(&pdev->dev);
346
347 /* shutdown the FPGA */
348 mutex_lock(&ts_nbus->lock);
349 pwm_disable(ts_nbus->pwm);
350 mutex_unlock(&ts_nbus->lock);
351
352 return 0;
353}
354
355static const struct of_device_id ts_nbus_of_match[] = {
356 { .compatible = "technologic,ts-nbus", },
357 { },
358};
359MODULE_DEVICE_TABLE(of, ts_nbus_of_match);
360
361static struct platform_driver ts_nbus_driver = {
362 .probe = ts_nbus_probe,
363 .remove = ts_nbus_remove,
364 .driver = {
365 .name = "ts_nbus",
366 .of_match_table = ts_nbus_of_match,
367 },
368};
369
370module_platform_driver(ts_nbus_driver);
371
372MODULE_ALIAS("platform:ts_nbus");
373MODULE_AUTHOR("Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>");
374MODULE_DESCRIPTION("Technologic Systems NBUS");
375MODULE_LICENSE("GPL v2");