1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2021 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
4 */
5
6 #include <linux/counter.h>
7 #include <linux/gpio/consumer.h>
8 #include <linux/interrupt.h>
9 #include <linux/irq.h>
10 #include <linux/mod_devicetable.h>
11 #include <linux/module.h>
12 #include <linux/platform_device.h>
13 #include <linux/types.h>
14
15 #define INTERRUPT_CNT_NAME "interrupt-cnt"
16
17 struct interrupt_cnt_priv {
18 atomic_t count;
19 struct gpio_desc *gpio;
20 int irq;
21 bool enabled;
22 struct counter_signal signals;
23 struct counter_synapse synapses;
24 struct counter_count cnts;
25 };
26
interrupt_cnt_isr(int irq,void * dev_id)27 static irqreturn_t interrupt_cnt_isr(int irq, void *dev_id)
28 {
29 struct counter_device *counter = dev_id;
30 struct interrupt_cnt_priv *priv = counter_priv(counter);
31
32 atomic_inc(&priv->count);
33
34 counter_push_event(counter, COUNTER_EVENT_CHANGE_OF_STATE, 0);
35
36 return IRQ_HANDLED;
37 }
38
interrupt_cnt_enable_read(struct counter_device * counter,struct counter_count * count,u8 * enable)39 static int interrupt_cnt_enable_read(struct counter_device *counter,
40 struct counter_count *count, u8 *enable)
41 {
42 struct interrupt_cnt_priv *priv = counter_priv(counter);
43
44 *enable = priv->enabled;
45
46 return 0;
47 }
48
interrupt_cnt_enable_write(struct counter_device * counter,struct counter_count * count,u8 enable)49 static int interrupt_cnt_enable_write(struct counter_device *counter,
50 struct counter_count *count, u8 enable)
51 {
52 struct interrupt_cnt_priv *priv = counter_priv(counter);
53
54 if (priv->enabled == enable)
55 return 0;
56
57 if (enable) {
58 priv->enabled = true;
59 enable_irq(priv->irq);
60 } else {
61 disable_irq(priv->irq);
62 priv->enabled = false;
63 }
64
65 return 0;
66 }
67
68 static struct counter_comp interrupt_cnt_ext[] = {
69 COUNTER_COMP_ENABLE(interrupt_cnt_enable_read,
70 interrupt_cnt_enable_write),
71 };
72
73 static const enum counter_synapse_action interrupt_cnt_synapse_actions[] = {
74 COUNTER_SYNAPSE_ACTION_RISING_EDGE,
75 };
76
interrupt_cnt_action_read(struct counter_device * counter,struct counter_count * count,struct counter_synapse * synapse,enum counter_synapse_action * action)77 static int interrupt_cnt_action_read(struct counter_device *counter,
78 struct counter_count *count,
79 struct counter_synapse *synapse,
80 enum counter_synapse_action *action)
81 {
82 *action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
83
84 return 0;
85 }
86
interrupt_cnt_read(struct counter_device * counter,struct counter_count * count,u64 * val)87 static int interrupt_cnt_read(struct counter_device *counter,
88 struct counter_count *count, u64 *val)
89 {
90 struct interrupt_cnt_priv *priv = counter_priv(counter);
91
92 *val = atomic_read(&priv->count);
93
94 return 0;
95 }
96
interrupt_cnt_write(struct counter_device * counter,struct counter_count * count,const u64 val)97 static int interrupt_cnt_write(struct counter_device *counter,
98 struct counter_count *count, const u64 val)
99 {
100 struct interrupt_cnt_priv *priv = counter_priv(counter);
101
102 if (val != (typeof(priv->count.counter))val)
103 return -ERANGE;
104
105 atomic_set(&priv->count, val);
106
107 return 0;
108 }
109
110 static const enum counter_function interrupt_cnt_functions[] = {
111 COUNTER_FUNCTION_INCREASE,
112 };
113
interrupt_cnt_function_read(struct counter_device * counter,struct counter_count * count,enum counter_function * function)114 static int interrupt_cnt_function_read(struct counter_device *counter,
115 struct counter_count *count,
116 enum counter_function *function)
117 {
118 *function = COUNTER_FUNCTION_INCREASE;
119
120 return 0;
121 }
122
interrupt_cnt_signal_read(struct counter_device * counter,struct counter_signal * signal,enum counter_signal_level * level)123 static int interrupt_cnt_signal_read(struct counter_device *counter,
124 struct counter_signal *signal,
125 enum counter_signal_level *level)
126 {
127 struct interrupt_cnt_priv *priv = counter_priv(counter);
128 int ret;
129
130 if (!priv->gpio)
131 return -EINVAL;
132
133 ret = gpiod_get_value(priv->gpio);
134 if (ret < 0)
135 return ret;
136
137 *level = ret ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
138
139 return 0;
140 }
141
interrupt_cnt_watch_validate(struct counter_device * counter,const struct counter_watch * watch)142 static int interrupt_cnt_watch_validate(struct counter_device *counter,
143 const struct counter_watch *watch)
144 {
145 if (watch->channel != 0 ||
146 watch->event != COUNTER_EVENT_CHANGE_OF_STATE)
147 return -EINVAL;
148
149 return 0;
150 }
151
152 static const struct counter_ops interrupt_cnt_ops = {
153 .action_read = interrupt_cnt_action_read,
154 .count_read = interrupt_cnt_read,
155 .count_write = interrupt_cnt_write,
156 .function_read = interrupt_cnt_function_read,
157 .signal_read = interrupt_cnt_signal_read,
158 .watch_validate = interrupt_cnt_watch_validate,
159 };
160
interrupt_cnt_probe(struct platform_device * pdev)161 static int interrupt_cnt_probe(struct platform_device *pdev)
162 {
163 struct device *dev = &pdev->dev;
164 struct counter_device *counter;
165 struct interrupt_cnt_priv *priv;
166 int ret;
167
168 counter = devm_counter_alloc(dev, sizeof(*priv));
169 if (!counter)
170 return -ENOMEM;
171 priv = counter_priv(counter);
172
173 priv->irq = platform_get_irq_optional(pdev, 0);
174 if (priv->irq == -ENXIO)
175 priv->irq = 0;
176 else if (priv->irq < 0)
177 return dev_err_probe(dev, priv->irq, "failed to get IRQ\n");
178
179 priv->gpio = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
180 if (IS_ERR(priv->gpio))
181 return dev_err_probe(dev, PTR_ERR(priv->gpio), "failed to get GPIO\n");
182
183 if (!priv->irq && !priv->gpio) {
184 dev_err(dev, "IRQ and GPIO are not found. At least one source should be provided\n");
185 return -ENODEV;
186 }
187
188 if (!priv->irq) {
189 int irq = gpiod_to_irq(priv->gpio);
190
191 if (irq < 0)
192 return dev_err_probe(dev, irq, "failed to get IRQ from GPIO\n");
193
194 priv->irq = irq;
195 }
196
197 priv->signals.name = devm_kasprintf(dev, GFP_KERNEL, "IRQ %d",
198 priv->irq);
199 if (!priv->signals.name)
200 return -ENOMEM;
201
202 counter->signals = &priv->signals;
203 counter->num_signals = 1;
204
205 priv->synapses.actions_list = interrupt_cnt_synapse_actions;
206 priv->synapses.num_actions = ARRAY_SIZE(interrupt_cnt_synapse_actions);
207 priv->synapses.signal = &priv->signals;
208
209 priv->cnts.name = "Channel 0 Count";
210 priv->cnts.functions_list = interrupt_cnt_functions;
211 priv->cnts.num_functions = ARRAY_SIZE(interrupt_cnt_functions);
212 priv->cnts.synapses = &priv->synapses;
213 priv->cnts.num_synapses = 1;
214 priv->cnts.ext = interrupt_cnt_ext;
215 priv->cnts.num_ext = ARRAY_SIZE(interrupt_cnt_ext);
216
217 counter->name = dev_name(dev);
218 counter->parent = dev;
219 counter->ops = &interrupt_cnt_ops;
220 counter->counts = &priv->cnts;
221 counter->num_counts = 1;
222
223 irq_set_status_flags(priv->irq, IRQ_NOAUTOEN);
224 ret = devm_request_irq(dev, priv->irq, interrupt_cnt_isr,
225 IRQF_TRIGGER_RISING | IRQF_NO_THREAD,
226 dev_name(dev), counter);
227 if (ret)
228 return ret;
229
230 ret = devm_counter_add(dev, counter);
231 if (ret < 0)
232 return dev_err_probe(dev, ret, "Failed to add counter\n");
233
234 return 0;
235 }
236
237 static const struct of_device_id interrupt_cnt_of_match[] = {
238 { .compatible = "interrupt-counter", },
239 {}
240 };
241 MODULE_DEVICE_TABLE(of, interrupt_cnt_of_match);
242
243 static struct platform_driver interrupt_cnt_driver = {
244 .probe = interrupt_cnt_probe,
245 .driver = {
246 .name = INTERRUPT_CNT_NAME,
247 .of_match_table = interrupt_cnt_of_match,
248 },
249 };
250 module_platform_driver(interrupt_cnt_driver);
251
252 MODULE_ALIAS("platform:interrupt-counter");
253 MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
254 MODULE_DESCRIPTION("Interrupt counter driver");
255 MODULE_LICENSE("GPL v2");
256 MODULE_IMPORT_NS(COUNTER);
257