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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
45void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
46{
47 enum mctrl_gpio_idx i;
48 struct gpio_desc *desc_array[UART_GPIO_MAX];
49 DECLARE_BITMAP(values, UART_GPIO_MAX);
50 unsigned int count = 0;
51
52 if (gpios == NULL)
53 return;
54
55 for (i = 0; i < UART_GPIO_MAX; i++)
56 if (gpios->gpio[i] && mctrl_gpio_flags_is_dir_out(i)) {
57 desc_array[count] = gpios->gpio[i];
58 __assign_bit(count, values,
59 mctrl & mctrl_gpios_desc[i].mctrl);
60 count++;
61 }
62 gpiod_set_array_value(count, desc_array, NULL, values);
63}
64EXPORT_SYMBOL_GPL(mctrl_gpio_set);
65
66struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
67 enum mctrl_gpio_idx gidx)
68{
69 if (gpios == NULL)
70 return NULL;
71
72 return gpios->gpio[gidx];
73}
74EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
75
76unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
77{
78 enum mctrl_gpio_idx i;
79
80 if (gpios == NULL)
81 return *mctrl;
82
83 for (i = 0; i < UART_GPIO_MAX; i++) {
84 if (gpios->gpio[i] && !mctrl_gpio_flags_is_dir_out(i)) {
85 if (gpiod_get_value(gpios->gpio[i]))
86 *mctrl |= mctrl_gpios_desc[i].mctrl;
87 else
88 *mctrl &= ~mctrl_gpios_desc[i].mctrl;
89 }
90 }
91
92 return *mctrl;
93}
94EXPORT_SYMBOL_GPL(mctrl_gpio_get);
95
96unsigned int
97mctrl_gpio_get_outputs(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_outputs);
116
117struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
118{
119 struct mctrl_gpios *gpios;
120 enum mctrl_gpio_idx i;
121
122 gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
123 if (!gpios)
124 return ERR_PTR(-ENOMEM);
125
126 for (i = 0; i < UART_GPIO_MAX; i++) {
127 char *gpio_str;
128 bool present;
129
130 /* Check if GPIO property exists and continue if not */
131 gpio_str = kasprintf(GFP_KERNEL, "%s-gpios",
132 mctrl_gpios_desc[i].name);
133 if (!gpio_str)
134 continue;
135
136 present = device_property_present(dev, gpio_str);
137 kfree(gpio_str);
138 if (!present)
139 continue;
140
141 gpios->gpio[i] =
142 devm_gpiod_get_index_optional(dev,
143 mctrl_gpios_desc[i].name,
144 idx,
145 mctrl_gpios_desc[i].flags);
146
147 if (IS_ERR(gpios->gpio[i]))
148 return ERR_CAST(gpios->gpio[i]);
149 }
150
151 return gpios;
152}
153EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto);
154
155#define MCTRL_ANY_DELTA (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
156static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
157{
158 struct mctrl_gpios *gpios = context;
159 struct uart_port *port = gpios->port;
160 u32 mctrl = gpios->mctrl_prev;
161 u32 mctrl_diff;
162 unsigned long flags;
163
164 mctrl_gpio_get(gpios, &mctrl);
165
166 spin_lock_irqsave(&port->lock, flags);
167
168 mctrl_diff = mctrl ^ gpios->mctrl_prev;
169 gpios->mctrl_prev = mctrl;
170
171 if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {
172 if ((mctrl_diff & mctrl) & TIOCM_RI)
173 port->icount.rng++;
174
175 if ((mctrl_diff & mctrl) & TIOCM_DSR)
176 port->icount.dsr++;
177
178 if (mctrl_diff & TIOCM_CD)
179 uart_handle_dcd_change(port, mctrl & TIOCM_CD);
180
181 if (mctrl_diff & TIOCM_CTS)
182 uart_handle_cts_change(port, mctrl & TIOCM_CTS);
183
184 wake_up_interruptible(&port->state->port.delta_msr_wait);
185 }
186
187 spin_unlock_irqrestore(&port->lock, flags);
188
189 return IRQ_HANDLED;
190}
191
192struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
193{
194 struct mctrl_gpios *gpios;
195 enum mctrl_gpio_idx i;
196
197 gpios = mctrl_gpio_init_noauto(port->dev, idx);
198 if (IS_ERR(gpios))
199 return gpios;
200
201 gpios->port = port;
202
203 for (i = 0; i < UART_GPIO_MAX; ++i) {
204 int ret;
205
206 if (!gpios->gpio[i] || mctrl_gpio_flags_is_dir_out(i))
207 continue;
208
209 ret = gpiod_to_irq(gpios->gpio[i]);
210 if (ret < 0) {
211 dev_err(port->dev,
212 "failed to find corresponding irq for %s (idx=%d, err=%d)\n",
213 mctrl_gpios_desc[i].name, idx, ret);
214 return ERR_PTR(ret);
215 }
216 gpios->irq[i] = ret;
217
218 /* irqs should only be enabled in .enable_ms */
219 irq_set_status_flags(gpios->irq[i], IRQ_NOAUTOEN);
220
221 ret = devm_request_irq(port->dev, gpios->irq[i],
222 mctrl_gpio_irq_handle,
223 IRQ_TYPE_EDGE_BOTH, dev_name(port->dev),
224 gpios);
225 if (ret) {
226 /* alternatively implement polling */
227 dev_err(port->dev,
228 "failed to request irq for %s (idx=%d, err=%d)\n",
229 mctrl_gpios_desc[i].name, idx, ret);
230 return ERR_PTR(ret);
231 }
232 }
233
234 return gpios;
235}
236EXPORT_SYMBOL_GPL(mctrl_gpio_init);
237
238void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
239{
240 enum mctrl_gpio_idx i;
241
242 if (gpios == NULL)
243 return;
244
245 for (i = 0; i < UART_GPIO_MAX; i++) {
246 if (gpios->irq[i])
247 devm_free_irq(gpios->port->dev, gpios->irq[i], gpios);
248
249 if (gpios->gpio[i])
250 devm_gpiod_put(dev, gpios->gpio[i]);
251 }
252 devm_kfree(dev, gpios);
253}
254EXPORT_SYMBOL_GPL(mctrl_gpio_free);
255
256void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
257{
258 enum mctrl_gpio_idx i;
259
260 if (gpios == NULL)
261 return;
262
263 /* .enable_ms may be called multiple times */
264 if (gpios->mctrl_on)
265 return;
266
267 gpios->mctrl_on = true;
268
269 /* get initial status of modem lines GPIOs */
270 mctrl_gpio_get(gpios, &gpios->mctrl_prev);
271
272 for (i = 0; i < UART_GPIO_MAX; ++i) {
273 if (!gpios->irq[i])
274 continue;
275
276 enable_irq(gpios->irq[i]);
277 }
278}
279EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);
280
281void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
282{
283 enum mctrl_gpio_idx i;
284
285 if (gpios == NULL)
286 return;
287
288 if (!gpios->mctrl_on)
289 return;
290
291 gpios->mctrl_on = false;
292
293 for (i = 0; i < UART_GPIO_MAX; ++i) {
294 if (!gpios->irq[i])
295 continue;
296
297 disable_irq(gpios->irq[i]);
298 }
299}
300EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms);
301
302MODULE_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");