drivers/counter/interrupt-cnt.c

   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
  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
  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
  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
  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
  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
  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
 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
 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
 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
 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);