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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Helpers for controlling modem lines via GPIO
4 *
5 * Copyright (C) 2014 Paratronic S.A.
6 */
7
8#include <linux/err.h>
9#include <linux/device.h>
10#include <linux/irq.h>
11#include <linux/gpio/consumer.h>
12#include <linux/termios.h>
13#include <linux/serial_core.h>
14#include <linux/module.h>
15#include <linux/property.h>
16
17#include "serial_mctrl_gpio.h"
18
19struct mctrl_gpios {
20 struct uart_port *port;
21 struct gpio_desc *gpio[UART_GPIO_MAX];
22 int irq[UART_GPIO_MAX];
23 unsigned int mctrl_prev;
24 bool mctrl_on;
25};
26
27static const struct {
28 const char *name;
29 unsigned int mctrl;
30 enum gpiod_flags flags;
31} mctrl_gpios_desc[UART_GPIO_MAX] = {
32 { "cts", TIOCM_CTS, GPIOD_IN, },
33 { "dsr", TIOCM_DSR, GPIOD_IN, },
34 { "dcd", TIOCM_CD, GPIOD_IN, },
35 { "rng", TIOCM_RNG, GPIOD_IN, },
36 { "rts", TIOCM_RTS, GPIOD_OUT_LOW, },
37 { "dtr", TIOCM_DTR, GPIOD_OUT_LOW, },
38};
39
40static bool mctrl_gpio_flags_is_dir_out(unsigned int idx)
41{
42 return mctrl_gpios_desc[idx].flags & GPIOD_FLAGS_BIT_DIR_OUT;
43}
44
45/**
46 * mctrl_gpio_set - set gpios according to mctrl state
47 * @gpios: gpios to set
48 * @mctrl: state to set
49 *
50 * Set the gpios according to the mctrl state.
51 */
52void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
53{
54 enum mctrl_gpio_idx i;
55 struct gpio_desc *desc_array[UART_GPIO_MAX];
56 DECLARE_BITMAP(values, UART_GPIO_MAX);
57 unsigned int count = 0;
58
59 if (gpios == NULL)
60 return;
61
62 for (i = 0; i < UART_GPIO_MAX; i++)
63 if (gpios->gpio[i] && mctrl_gpio_flags_is_dir_out(i)) {
64 desc_array[count] = gpios->gpio[i];
65 __assign_bit(count, values,
66 mctrl & mctrl_gpios_desc[i].mctrl);
67 count++;
68 }
69 gpiod_set_array_value(count, desc_array, NULL, values);
70}
71EXPORT_SYMBOL_GPL(mctrl_gpio_set);
72
73/**
74 * mctrl_gpio_to_gpiod - obtain gpio_desc of modem line index
75 * @gpios: gpios to look into
76 * @gidx: index of the modem line
77 * Returns: the gpio_desc structure associated to the modem line index
78 */
79struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
80 enum mctrl_gpio_idx gidx)
81{
82 if (gpios == NULL)
83 return NULL;
84
85 return gpios->gpio[gidx];
86}
87EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
88
89/**
90 * mctrl_gpio_get - update mctrl with the gpios values.
91 * @gpios: gpios to get the info from
92 * @mctrl: mctrl to set
93 * Returns: modified mctrl (the same value as in @mctrl)
94 *
95 * Update mctrl with the gpios values.
96 */
97unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
98{
99 enum mctrl_gpio_idx i;
100
101 if (gpios == NULL)
102 return *mctrl;
103
104 for (i = 0; i < UART_GPIO_MAX; i++) {
105 if (gpios->gpio[i] && !mctrl_gpio_flags_is_dir_out(i)) {
106 if (gpiod_get_value(gpios->gpio[i]))
107 *mctrl |= mctrl_gpios_desc[i].mctrl;
108 else
109 *mctrl &= ~mctrl_gpios_desc[i].mctrl;
110 }
111 }
112
113 return *mctrl;
114}
115EXPORT_SYMBOL_GPL(mctrl_gpio_get);
116
117unsigned int
118mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl)
119{
120 enum mctrl_gpio_idx i;
121
122 if (gpios == NULL)
123 return *mctrl;
124
125 for (i = 0; i < UART_GPIO_MAX; i++) {
126 if (gpios->gpio[i] && mctrl_gpio_flags_is_dir_out(i)) {
127 if (gpiod_get_value(gpios->gpio[i]))
128 *mctrl |= mctrl_gpios_desc[i].mctrl;
129 else
130 *mctrl &= ~mctrl_gpios_desc[i].mctrl;
131 }
132 }
133
134 return *mctrl;
135}
136EXPORT_SYMBOL_GPL(mctrl_gpio_get_outputs);
137
138struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
139{
140 struct mctrl_gpios *gpios;
141 enum mctrl_gpio_idx i;
142
143 gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
144 if (!gpios)
145 return ERR_PTR(-ENOMEM);
146
147 for (i = 0; i < UART_GPIO_MAX; i++) {
148 char *gpio_str;
149 bool present;
150
151 /* Check if GPIO property exists and continue if not */
152 gpio_str = kasprintf(GFP_KERNEL, "%s-gpios",
153 mctrl_gpios_desc[i].name);
154 if (!gpio_str)
155 continue;
156
157 present = device_property_present(dev, gpio_str);
158 kfree(gpio_str);
159 if (!present)
160 continue;
161
162 gpios->gpio[i] =
163 devm_gpiod_get_index_optional(dev,
164 mctrl_gpios_desc[i].name,
165 idx,
166 mctrl_gpios_desc[i].flags);
167
168 if (IS_ERR(gpios->gpio[i]))
169 return ERR_CAST(gpios->gpio[i]);
170 }
171
172 return gpios;
173}
174EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto);
175
176#define MCTRL_ANY_DELTA (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
177static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
178{
179 struct mctrl_gpios *gpios = context;
180 struct uart_port *port = gpios->port;
181 u32 mctrl = gpios->mctrl_prev;
182 u32 mctrl_diff;
183 unsigned long flags;
184
185 mctrl_gpio_get(gpios, &mctrl);
186
187 uart_port_lock_irqsave(port, &flags);
188
189 mctrl_diff = mctrl ^ gpios->mctrl_prev;
190 gpios->mctrl_prev = mctrl;
191
192 if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {
193 if ((mctrl_diff & mctrl) & TIOCM_RI)
194 port->icount.rng++;
195
196 if ((mctrl_diff & mctrl) & TIOCM_DSR)
197 port->icount.dsr++;
198
199 if (mctrl_diff & TIOCM_CD)
200 uart_handle_dcd_change(port, mctrl & TIOCM_CD);
201
202 if (mctrl_diff & TIOCM_CTS)
203 uart_handle_cts_change(port, mctrl & TIOCM_CTS);
204
205 wake_up_interruptible(&port->state->port.delta_msr_wait);
206 }
207
208 uart_port_unlock_irqrestore(port, flags);
209
210 return IRQ_HANDLED;
211}
212
213/**
214 * mctrl_gpio_init - initialize uart gpios
215 * @port: port to initialize gpios for
216 * @idx: index of the gpio in the @port's device
217 *
218 * This will get the {cts,rts,...}-gpios from device tree if they are present
219 * and request them, set direction etc, and return an allocated structure.
220 * `devm_*` functions are used, so there's no need to call mctrl_gpio_free().
221 * As this sets up the irq handling, make sure to not handle changes to the
222 * gpio input lines in your driver, too.
223 */
224struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
225{
226 struct mctrl_gpios *gpios;
227 enum mctrl_gpio_idx i;
228
229 gpios = mctrl_gpio_init_noauto(port->dev, idx);
230 if (IS_ERR(gpios))
231 return gpios;
232
233 gpios->port = port;
234
235 for (i = 0; i < UART_GPIO_MAX; ++i) {
236 int ret;
237
238 if (!gpios->gpio[i] || mctrl_gpio_flags_is_dir_out(i))
239 continue;
240
241 ret = gpiod_to_irq(gpios->gpio[i]);
242 if (ret < 0) {
243 dev_err(port->dev,
244 "failed to find corresponding irq for %s (idx=%d, err=%d)\n",
245 mctrl_gpios_desc[i].name, idx, ret);
246 return ERR_PTR(ret);
247 }
248 gpios->irq[i] = ret;
249
250 /* irqs should only be enabled in .enable_ms */
251 irq_set_status_flags(gpios->irq[i], IRQ_NOAUTOEN);
252
253 ret = devm_request_irq(port->dev, gpios->irq[i],
254 mctrl_gpio_irq_handle,
255 IRQ_TYPE_EDGE_BOTH, dev_name(port->dev),
256 gpios);
257 if (ret) {
258 /* alternatively implement polling */
259 dev_err(port->dev,
260 "failed to request irq for %s (idx=%d, err=%d)\n",
261 mctrl_gpios_desc[i].name, idx, ret);
262 return ERR_PTR(ret);
263 }
264 }
265
266 return gpios;
267}
268EXPORT_SYMBOL_GPL(mctrl_gpio_init);
269
270/**
271 * mctrl_gpio_free - explicitly free uart gpios
272 * @dev: uart port's device
273 * @gpios: gpios structure to be freed
274 *
275 * This will free the requested gpios in mctrl_gpio_init(). As `devm_*`
276 * functions are used, there's generally no need to call this function.
277 */
278void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
279{
280 enum mctrl_gpio_idx i;
281
282 if (gpios == NULL)
283 return;
284
285 for (i = 0; i < UART_GPIO_MAX; i++) {
286 if (gpios->irq[i])
287 devm_free_irq(gpios->port->dev, gpios->irq[i], gpios);
288
289 if (gpios->gpio[i])
290 devm_gpiod_put(dev, gpios->gpio[i]);
291 }
292 devm_kfree(dev, gpios);
293}
294EXPORT_SYMBOL_GPL(mctrl_gpio_free);
295
296/**
297 * mctrl_gpio_enable_ms - enable irqs and handling of changes to the ms lines
298 * @gpios: gpios to enable
299 */
300void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
301{
302 enum mctrl_gpio_idx i;
303
304 if (gpios == NULL)
305 return;
306
307 /* .enable_ms may be called multiple times */
308 if (gpios->mctrl_on)
309 return;
310
311 gpios->mctrl_on = true;
312
313 /* get initial status of modem lines GPIOs */
314 mctrl_gpio_get(gpios, &gpios->mctrl_prev);
315
316 for (i = 0; i < UART_GPIO_MAX; ++i) {
317 if (!gpios->irq[i])
318 continue;
319
320 enable_irq(gpios->irq[i]);
321 }
322}
323EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);
324
325/**
326 * mctrl_gpio_disable_ms - disable irqs and handling of changes to the ms lines
327 * @gpios: gpios to disable
328 */
329void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
330{
331 enum mctrl_gpio_idx i;
332
333 if (gpios == NULL)
334 return;
335
336 if (!gpios->mctrl_on)
337 return;
338
339 gpios->mctrl_on = false;
340
341 for (i = 0; i < UART_GPIO_MAX; ++i) {
342 if (!gpios->irq[i])
343 continue;
344
345 disable_irq(gpios->irq[i]);
346 }
347}
348EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms);
349
350void mctrl_gpio_enable_irq_wake(struct mctrl_gpios *gpios)
351{
352 enum mctrl_gpio_idx i;
353
354 if (!gpios)
355 return;
356
357 if (!gpios->mctrl_on)
358 return;
359
360 for (i = 0; i < UART_GPIO_MAX; ++i) {
361 if (!gpios->irq[i])
362 continue;
363
364 enable_irq_wake(gpios->irq[i]);
365 }
366}
367EXPORT_SYMBOL_GPL(mctrl_gpio_enable_irq_wake);
368
369void mctrl_gpio_disable_irq_wake(struct mctrl_gpios *gpios)
370{
371 enum mctrl_gpio_idx i;
372
373 if (!gpios)
374 return;
375
376 if (!gpios->mctrl_on)
377 return;
378
379 for (i = 0; i < UART_GPIO_MAX; ++i) {
380 if (!gpios->irq[i])
381 continue;
382
383 disable_irq_wake(gpios->irq[i]);
384 }
385}
386EXPORT_SYMBOL_GPL(mctrl_gpio_disable_irq_wake);
387
388MODULE_LICENSE("GPL");
1/*
2 * Helpers for controlling modem lines via GPIO
3 *
4 * Copyright (C) 2014 Paratronic S.A.
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/err.h>
18#include <linux/device.h>
19#include <linux/irq.h>
20#include <linux/gpio/consumer.h>
21#include <linux/termios.h>
22#include <linux/serial_core.h>
23#include <linux/module.h>
24
25#include "serial_mctrl_gpio.h"
26
27struct mctrl_gpios {
28 struct uart_port *port;
29 struct gpio_desc *gpio[UART_GPIO_MAX];
30 int irq[UART_GPIO_MAX];
31 unsigned int mctrl_prev;
32 bool mctrl_on;
33};
34
35static const struct {
36 const char *name;
37 unsigned int mctrl;
38 bool dir_out;
39} mctrl_gpios_desc[UART_GPIO_MAX] = {
40 { "cts", TIOCM_CTS, false, },
41 { "dsr", TIOCM_DSR, false, },
42 { "dcd", TIOCM_CD, false, },
43 { "rng", TIOCM_RNG, false, },
44 { "rts", TIOCM_RTS, true, },
45 { "dtr", TIOCM_DTR, true, },
46};
47
48void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
49{
50 enum mctrl_gpio_idx i;
51 struct gpio_desc *desc_array[UART_GPIO_MAX];
52 int value_array[UART_GPIO_MAX];
53 unsigned int count = 0;
54
55 if (gpios == NULL)
56 return;
57
58 for (i = 0; i < UART_GPIO_MAX; i++)
59 if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
60 desc_array[count] = gpios->gpio[i];
61 value_array[count] = !!(mctrl & mctrl_gpios_desc[i].mctrl);
62 count++;
63 }
64 gpiod_set_array_value(count, desc_array, value_array);
65}
66EXPORT_SYMBOL_GPL(mctrl_gpio_set);
67
68struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
69 enum mctrl_gpio_idx gidx)
70{
71 return gpios->gpio[gidx];
72}
73EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
74
75unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
76{
77 enum mctrl_gpio_idx i;
78
79 if (gpios == NULL)
80 return *mctrl;
81
82 for (i = 0; i < UART_GPIO_MAX; i++) {
83 if (gpios->gpio[i] && !mctrl_gpios_desc[i].dir_out) {
84 if (gpiod_get_value(gpios->gpio[i]))
85 *mctrl |= mctrl_gpios_desc[i].mctrl;
86 else
87 *mctrl &= ~mctrl_gpios_desc[i].mctrl;
88 }
89 }
90
91 return *mctrl;
92}
93EXPORT_SYMBOL_GPL(mctrl_gpio_get);
94
95unsigned int
96mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl)
97{
98 enum mctrl_gpio_idx i;
99
100 if (gpios == NULL)
101 return *mctrl;
102
103 for (i = 0; i < UART_GPIO_MAX; i++) {
104 if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
105 if (gpiod_get_value(gpios->gpio[i]))
106 *mctrl |= mctrl_gpios_desc[i].mctrl;
107 else
108 *mctrl &= ~mctrl_gpios_desc[i].mctrl;
109 }
110 }
111
112 return *mctrl;
113}
114EXPORT_SYMBOL_GPL(mctrl_gpio_get_outputs);
115
116struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
117{
118 struct mctrl_gpios *gpios;
119 enum mctrl_gpio_idx i;
120
121 gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
122 if (!gpios)
123 return ERR_PTR(-ENOMEM);
124
125 for (i = 0; i < UART_GPIO_MAX; i++) {
126 enum gpiod_flags flags;
127
128 if (mctrl_gpios_desc[i].dir_out)
129 flags = GPIOD_OUT_LOW;
130 else
131 flags = GPIOD_IN;
132
133 gpios->gpio[i] =
134 devm_gpiod_get_index_optional(dev,
135 mctrl_gpios_desc[i].name,
136 idx, flags);
137
138 if (IS_ERR(gpios->gpio[i]))
139 return ERR_CAST(gpios->gpio[i]);
140 }
141
142 return gpios;
143}
144EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto);
145
146#define MCTRL_ANY_DELTA (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
147static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
148{
149 struct mctrl_gpios *gpios = context;
150 struct uart_port *port = gpios->port;
151 u32 mctrl = gpios->mctrl_prev;
152 u32 mctrl_diff;
153 unsigned long flags;
154
155 mctrl_gpio_get(gpios, &mctrl);
156
157 spin_lock_irqsave(&port->lock, flags);
158
159 mctrl_diff = mctrl ^ gpios->mctrl_prev;
160 gpios->mctrl_prev = mctrl;
161
162 if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {
163 if ((mctrl_diff & mctrl) & TIOCM_RI)
164 port->icount.rng++;
165
166 if ((mctrl_diff & mctrl) & TIOCM_DSR)
167 port->icount.dsr++;
168
169 if (mctrl_diff & TIOCM_CD)
170 uart_handle_dcd_change(port, mctrl & TIOCM_CD);
171
172 if (mctrl_diff & TIOCM_CTS)
173 uart_handle_cts_change(port, mctrl & TIOCM_CTS);
174
175 wake_up_interruptible(&port->state->port.delta_msr_wait);
176 }
177
178 spin_unlock_irqrestore(&port->lock, flags);
179
180 return IRQ_HANDLED;
181}
182
183struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
184{
185 struct mctrl_gpios *gpios;
186 enum mctrl_gpio_idx i;
187
188 gpios = mctrl_gpio_init_noauto(port->dev, idx);
189 if (IS_ERR(gpios))
190 return gpios;
191
192 gpios->port = port;
193
194 for (i = 0; i < UART_GPIO_MAX; ++i) {
195 int ret;
196
197 if (!gpios->gpio[i] || mctrl_gpios_desc[i].dir_out)
198 continue;
199
200 ret = gpiod_to_irq(gpios->gpio[i]);
201 if (ret <= 0) {
202 dev_err(port->dev,
203 "failed to find corresponding irq for %s (idx=%d, err=%d)\n",
204 mctrl_gpios_desc[i].name, idx, ret);
205 return ERR_PTR(ret);
206 }
207 gpios->irq[i] = ret;
208
209 /* irqs should only be enabled in .enable_ms */
210 irq_set_status_flags(gpios->irq[i], IRQ_NOAUTOEN);
211
212 ret = devm_request_irq(port->dev, gpios->irq[i],
213 mctrl_gpio_irq_handle,
214 IRQ_TYPE_EDGE_BOTH, dev_name(port->dev),
215 gpios);
216 if (ret) {
217 /* alternatively implement polling */
218 dev_err(port->dev,
219 "failed to request irq for %s (idx=%d, err=%d)\n",
220 mctrl_gpios_desc[i].name, idx, ret);
221 return ERR_PTR(ret);
222 }
223 }
224
225 return gpios;
226}
227EXPORT_SYMBOL_GPL(mctrl_gpio_init);
228
229void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
230{
231 enum mctrl_gpio_idx i;
232
233 if (gpios == NULL)
234 return;
235
236 for (i = 0; i < UART_GPIO_MAX; i++) {
237 if (gpios->irq[i])
238 devm_free_irq(gpios->port->dev, gpios->irq[i], gpios);
239
240 if (gpios->gpio[i])
241 devm_gpiod_put(dev, gpios->gpio[i]);
242 }
243 devm_kfree(dev, gpios);
244}
245EXPORT_SYMBOL_GPL(mctrl_gpio_free);
246
247void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
248{
249 enum mctrl_gpio_idx i;
250
251 if (gpios == NULL)
252 return;
253
254 /* .enable_ms may be called multiple times */
255 if (gpios->mctrl_on)
256 return;
257
258 gpios->mctrl_on = true;
259
260 /* get initial status of modem lines GPIOs */
261 mctrl_gpio_get(gpios, &gpios->mctrl_prev);
262
263 for (i = 0; i < UART_GPIO_MAX; ++i) {
264 if (!gpios->irq[i])
265 continue;
266
267 enable_irq(gpios->irq[i]);
268 }
269}
270EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);
271
272void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
273{
274 enum mctrl_gpio_idx i;
275
276 if (gpios == NULL)
277 return;
278
279 if (!gpios->mctrl_on)
280 return;
281
282 gpios->mctrl_on = false;
283
284 for (i = 0; i < UART_GPIO_MAX; ++i) {
285 if (!gpios->irq[i])
286 continue;
287
288 disable_irq(gpios->irq[i]);
289 }
290}
291EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms);
292
293MODULE_LICENSE("GPL");