tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
17struct 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
27static 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
39static 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
49static 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
68static struct counter_comp interrupt_cnt_ext[] = {
69 COUNTER_COMP_ENABLE(interrupt_cnt_enable_read,
70 interrupt_cnt_enable_write),
71};
72
73static const enum counter_synapse_action interrupt_cnt_synapse_actions[] = {
74 COUNTER_SYNAPSE_ACTION_RISING_EDGE,
75};
76
77static 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
87static 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
97static 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
110static const enum counter_function interrupt_cnt_functions[] = {
111 COUNTER_FUNCTION_INCREASE,
112};
113
114static 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
123static 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
142static const struct counter_ops interrupt_cnt_ops = {
143 .action_read = interrupt_cnt_action_read,
144 .count_read = interrupt_cnt_read,
145 .count_write = interrupt_cnt_write,
146 .function_read = interrupt_cnt_function_read,
147 .signal_read = interrupt_cnt_signal_read,
148};
149
150static int interrupt_cnt_probe(struct platform_device *pdev)
151{
152 struct device *dev = &pdev->dev;
153 struct counter_device *counter;
154 struct interrupt_cnt_priv *priv;
155 int ret;
156
157 counter = devm_counter_alloc(dev, sizeof(*priv));
158 if (!counter)
159 return -ENOMEM;
160 priv = counter_priv(counter);
161
162 priv->irq = platform_get_irq_optional(pdev, 0);
163 if (priv->irq == -ENXIO)
164 priv->irq = 0;
165 else if (priv->irq < 0)
166 return dev_err_probe(dev, priv->irq, "failed to get IRQ\n");
167
168 priv->gpio = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
169 if (IS_ERR(priv->gpio))
170 return dev_err_probe(dev, PTR_ERR(priv->gpio), "failed to get GPIO\n");
171
172 if (!priv->irq && !priv->gpio) {
173 dev_err(dev, "IRQ and GPIO are not found. At least one source should be provided\n");
174 return -ENODEV;
175 }
176
177 if (!priv->irq) {
178 int irq = gpiod_to_irq(priv->gpio);
179
180 if (irq < 0)
181 return dev_err_probe(dev, irq, "failed to get IRQ from GPIO\n");
182
183 priv->irq = irq;
184 }
185
186 priv->signals.name = devm_kasprintf(dev, GFP_KERNEL, "IRQ %d",
187 priv->irq);
188 if (!priv->signals.name)
189 return -ENOMEM;
190
191 counter->signals = &priv->signals;
192 counter->num_signals = 1;
193
194 priv->synapses.actions_list = interrupt_cnt_synapse_actions;
195 priv->synapses.num_actions = ARRAY_SIZE(interrupt_cnt_synapse_actions);
196 priv->synapses.signal = &priv->signals;
197
198 priv->cnts.name = "Channel 0 Count";
199 priv->cnts.functions_list = interrupt_cnt_functions;
200 priv->cnts.num_functions = ARRAY_SIZE(interrupt_cnt_functions);
201 priv->cnts.synapses = &priv->synapses;
202 priv->cnts.num_synapses = 1;
203 priv->cnts.ext = interrupt_cnt_ext;
204 priv->cnts.num_ext = ARRAY_SIZE(interrupt_cnt_ext);
205
206 counter->name = dev_name(dev);
207 counter->parent = dev;
208 counter->ops = &interrupt_cnt_ops;
209 counter->counts = &priv->cnts;
210 counter->num_counts = 1;
211
212 irq_set_status_flags(priv->irq, IRQ_NOAUTOEN);
213 ret = devm_request_irq(dev, priv->irq, interrupt_cnt_isr,
214 IRQF_TRIGGER_RISING | IRQF_NO_THREAD,
215 dev_name(dev), counter);
216 if (ret)
217 return ret;
218
219 ret = devm_counter_add(dev, counter);
220 if (ret < 0)
221 return dev_err_probe(dev, ret, "Failed to add counter\n");
222
223 return 0;
224}
225
226static const struct of_device_id interrupt_cnt_of_match[] = {
227 { .compatible = "interrupt-counter", },
228 {}
229};
230MODULE_DEVICE_TABLE(of, interrupt_cnt_of_match);
231
232static struct platform_driver interrupt_cnt_driver = {
233 .probe = interrupt_cnt_probe,
234 .driver = {
235 .name = INTERRUPT_CNT_NAME,
236 .of_match_table = interrupt_cnt_of_match,
237 },
238};
239module_platform_driver(interrupt_cnt_driver);
240
241MODULE_ALIAS("platform:interrupt-counter");
242MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
243MODULE_DESCRIPTION("Interrupt counter driver");
244MODULE_LICENSE("GPL v2");