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
  14 #define INTERRUPT_CNT_NAME "interrupt-cnt"
  15
  16 struct interrupt_cnt_priv {
  17         atomic_t count;
  18         struct counter_device counter;
  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 interrupt_cnt_priv *priv = dev_id;
  30
  31         atomic_inc(&priv->count);
  32
  33         return IRQ_HANDLED;
  34 }
  35
  36 static ssize_t interrupt_cnt_enable_read(struct counter_device *counter,
  37                                          struct counter_count *count,
  38                                          void *private, char *buf)
  39 {
  40         struct interrupt_cnt_priv *priv = counter->priv;
  41
  42         return sysfs_emit(buf, "%d\n", priv->enabled);
  43 }
  44
  45 static ssize_t interrupt_cnt_enable_write(struct counter_device *counter,
  46                                           struct counter_count *count,
  47                                           void *private, const char *buf,
  48                                           size_t len)
  49 {
  50         struct interrupt_cnt_priv *priv = counter->priv;
  51         bool enable;
  52         ssize_t ret;
  53
  54         ret = kstrtobool(buf, &enable);
  55         if (ret)
  56                 return ret;
  57
  58         if (priv->enabled == enable)
  59                 return len;
  60
  61         if (enable) {
  62                 priv->enabled = true;
  63                 enable_irq(priv->irq);
  64         } else {
  65                 disable_irq(priv->irq);
  66                 priv->enabled = false;
  67         }
  68
  69         return len;
  70 }
  71
  72 static const struct counter_count_ext interrupt_cnt_ext[] = {
  73         {
  74                 .name = "enable",
  75                 .read = interrupt_cnt_enable_read,
  76                 .write = interrupt_cnt_enable_write,
  77         },
  78 };
  79
  80 static const enum counter_synapse_action interrupt_cnt_synapse_actions[] = {
  81         COUNTER_SYNAPSE_ACTION_RISING_EDGE,
  82 };
  83
  84 static int interrupt_cnt_action_get(struct counter_device *counter,
  85                                     struct counter_count *count,
  86                                     struct counter_synapse *synapse,
  87                                     size_t *action)
  88 {
  89         *action = 0;
  90
  91         return 0;
  92 }
  93
  94 static int interrupt_cnt_read(struct counter_device *counter,
  95                               struct counter_count *count, unsigned long *val)
  96 {
  97         struct interrupt_cnt_priv *priv = counter->priv;
  98
  99         *val = atomic_read(&priv->count);
 100
 101         return 0;
 102 }
 103
 104 static int interrupt_cnt_write(struct counter_device *counter,
 105                                struct counter_count *count,
 106                                const unsigned long val)
 107 {
 108         struct interrupt_cnt_priv *priv = counter->priv;
 109
 110         atomic_set(&priv->count, val);
 111
 112         return 0;
 113 }
 114
 115 static const enum counter_count_function interrupt_cnt_functions[] = {
 116         COUNTER_COUNT_FUNCTION_INCREASE,
 117 };
 118
 119 static int interrupt_cnt_function_get(struct counter_device *counter,
 120                                       struct counter_count *count,
 121                                       size_t *function)
 122 {
 123         *function = 0;
 124
 125         return 0;
 126 }
 127
 128 static int interrupt_cnt_signal_read(struct counter_device *counter,
 129                                      struct counter_signal *signal,
 130                                      enum counter_signal_value *val)
 131 {
 132         struct interrupt_cnt_priv *priv = counter->priv;
 133         int ret;
 134
 135         if (!priv->gpio)
 136                 return -EINVAL;
 137
 138         ret = gpiod_get_value(priv->gpio);
 139         if (ret < 0)
 140                 return ret;
 141
 142         *val = ret ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW;
 143
 144         return 0;
 145 }
 146
 147 static const struct counter_ops interrupt_cnt_ops = {
 148         .action_get = interrupt_cnt_action_get,
 149         .count_read = interrupt_cnt_read,
 150         .count_write = interrupt_cnt_write,
 151         .function_get = interrupt_cnt_function_get,
 152         .signal_read  = interrupt_cnt_signal_read,
 153 };
 154
 155 static int interrupt_cnt_probe(struct platform_device *pdev)
 156 {
 157         struct device *dev = &pdev->dev;
 158         struct interrupt_cnt_priv *priv;
 159         int ret;
 160
 161         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 162         if (!priv)
 163                 return -ENOMEM;
 164
 165         priv->irq = platform_get_irq_optional(pdev,  0);
 166         if (priv->irq == -ENXIO)
 167                 priv->irq = 0;
 168         else if (priv->irq < 0)
 169                 return dev_err_probe(dev, priv->irq, "failed to get IRQ\n");
 170
 171         priv->gpio = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
 172         if (IS_ERR(priv->gpio))
 173                 return dev_err_probe(dev, PTR_ERR(priv->gpio), "failed to get GPIO\n");
 174
 175         if (!priv->irq && !priv->gpio) {
 176                 dev_err(dev, "IRQ and GPIO are not found. At least one source should be provided\n");
 177                 return -ENODEV;
 178         }
 179
 180         if (!priv->irq) {
 181                 int irq = gpiod_to_irq(priv->gpio);
 182
 183                 if (irq < 0)
 184                         return dev_err_probe(dev, irq, "failed to get IRQ from GPIO\n");
 185
 186                 priv->irq = irq;
 187         }
 188
 189         priv->signals.name = devm_kasprintf(dev, GFP_KERNEL, "IRQ %d",
 190                                             priv->irq);
 191         if (!priv->signals.name)
 192                 return -ENOMEM;
 193
 194         priv->counter.signals = &priv->signals;
 195         priv->counter.num_signals = 1;
 196
 197         priv->synapses.actions_list = interrupt_cnt_synapse_actions;
 198         priv->synapses.num_actions = ARRAY_SIZE(interrupt_cnt_synapse_actions);
 199         priv->synapses.signal = &priv->signals;
 200
 201         priv->cnts.name = "Channel 0 Count";
 202         priv->cnts.functions_list = interrupt_cnt_functions;
 203         priv->cnts.num_functions = ARRAY_SIZE(interrupt_cnt_functions);
 204         priv->cnts.synapses = &priv->synapses;
 205         priv->cnts.num_synapses = 1;
 206         priv->cnts.ext = interrupt_cnt_ext;
 207         priv->cnts.num_ext = ARRAY_SIZE(interrupt_cnt_ext);
 208
 209         priv->counter.priv = priv;
 210         priv->counter.name = dev_name(dev);
 211         priv->counter.parent = dev;
 212         priv->counter.ops = &interrupt_cnt_ops;
 213         priv->counter.counts = &priv->cnts;
 214         priv->counter.num_counts = 1;
 215
 216         irq_set_status_flags(priv->irq, IRQ_NOAUTOEN);
 217         ret = devm_request_irq(dev, priv->irq, interrupt_cnt_isr,
 218                                IRQF_TRIGGER_RISING | IRQF_NO_THREAD,
 219                                dev_name(dev), priv);
 220         if (ret)
 221                 return ret;
 222
 223         return devm_counter_register(dev, &priv->counter);
 224 }
 225
 226 static const struct of_device_id interrupt_cnt_of_match[] = {
 227         { .compatible = "interrupt-counter", },
 228         {}
 229 };
 230 MODULE_DEVICE_TABLE(of, interrupt_cnt_of_match);
 231
 232 static 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 };
 239 module_platform_driver(interrupt_cnt_driver);
 240
 241 MODULE_ALIAS("platform:interrupt-counter");
 242 MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
 243 MODULE_DESCRIPTION("Interrupt counter driver");
 244 MODULE_LICENSE("GPL v2");