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         if (val != (typeof(priv->count.counter))val)
 111                 return -ERANGE;
 112
 113         atomic_set(&priv->count, val);
 114
 115         return 0;
 116 }
 117
 118 static const enum counter_function interrupt_cnt_functions[] = {
 119         COUNTER_FUNCTION_INCREASE,
 120 };
 121
 122 static int interrupt_cnt_function_get(struct counter_device *counter,
 123                                       struct counter_count *count,
 124                                       size_t *function)
 125 {
 126         *function = 0;
 127
 128         return 0;
 129 }
 130
 131 static int interrupt_cnt_signal_read(struct counter_device *counter,
 132                                      struct counter_signal *signal,
 133                                      enum counter_signal_level *level)
 134 {
 135         struct interrupt_cnt_priv *priv = counter->priv;
 136         int ret;
 137
 138         if (!priv->gpio)
 139                 return -EINVAL;
 140
 141         ret = gpiod_get_value(priv->gpio);
 142         if (ret < 0)
 143                 return ret;
 144
 145         *level = ret ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
 146
 147         return 0;
 148 }
 149
 150 static const struct counter_ops interrupt_cnt_ops = {
 151         .action_get = interrupt_cnt_action_get,
 152         .count_read = interrupt_cnt_read,
 153         .count_write = interrupt_cnt_write,
 154         .function_get = interrupt_cnt_function_get,
 155         .signal_read  = interrupt_cnt_signal_read,
 156 };
 157
 158 static int interrupt_cnt_probe(struct platform_device *pdev)
 159 {
 160         struct device *dev = &pdev->dev;
 161         struct interrupt_cnt_priv *priv;
 162         int ret;
 163
 164         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 165         if (!priv)
 166                 return -ENOMEM;
 167
 168         priv->irq = platform_get_irq_optional(pdev,  0);
 169         if (priv->irq == -ENXIO)
 170                 priv->irq = 0;
 171         else if (priv->irq < 0)
 172                 return dev_err_probe(dev, priv->irq, "failed to get IRQ\n");
 173
 174         priv->gpio = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
 175         if (IS_ERR(priv->gpio))
 176                 return dev_err_probe(dev, PTR_ERR(priv->gpio), "failed to get GPIO\n");
 177
 178         if (!priv->irq && !priv->gpio) {
 179                 dev_err(dev, "IRQ and GPIO are not found. At least one source should be provided\n");
 180                 return -ENODEV;
 181         }
 182
 183         if (!priv->irq) {
 184                 int irq = gpiod_to_irq(priv->gpio);
 185
 186                 if (irq < 0)
 187                         return dev_err_probe(dev, irq, "failed to get IRQ from GPIO\n");
 188
 189                 priv->irq = irq;
 190         }
 191
 192         priv->signals.name = devm_kasprintf(dev, GFP_KERNEL, "IRQ %d",
 193                                             priv->irq);
 194         if (!priv->signals.name)
 195                 return -ENOMEM;
 196
 197         priv->counter.signals = &priv->signals;
 198         priv->counter.num_signals = 1;
 199
 200         priv->synapses.actions_list = interrupt_cnt_synapse_actions;
 201         priv->synapses.num_actions = ARRAY_SIZE(interrupt_cnt_synapse_actions);
 202         priv->synapses.signal = &priv->signals;
 203
 204         priv->cnts.name = "Channel 0 Count";
 205         priv->cnts.functions_list = interrupt_cnt_functions;
 206         priv->cnts.num_functions = ARRAY_SIZE(interrupt_cnt_functions);
 207         priv->cnts.synapses = &priv->synapses;
 208         priv->cnts.num_synapses = 1;
 209         priv->cnts.ext = interrupt_cnt_ext;
 210         priv->cnts.num_ext = ARRAY_SIZE(interrupt_cnt_ext);
 211
 212         priv->counter.priv = priv;
 213         priv->counter.name = dev_name(dev);
 214         priv->counter.parent = dev;
 215         priv->counter.ops = &interrupt_cnt_ops;
 216         priv->counter.counts = &priv->cnts;
 217         priv->counter.num_counts = 1;
 218
 219         irq_set_status_flags(priv->irq, IRQ_NOAUTOEN);
 220         ret = devm_request_irq(dev, priv->irq, interrupt_cnt_isr,
 221                                IRQF_TRIGGER_RISING | IRQF_NO_THREAD,
 222                                dev_name(dev), priv);
 223         if (ret)
 224                 return ret;
 225
 226         return devm_counter_register(dev, &priv->counter);
 227 }
 228
 229 static const struct of_device_id interrupt_cnt_of_match[] = {
 230         { .compatible = "interrupt-counter", },
 231         {}
 232 };
 233 MODULE_DEVICE_TABLE(of, interrupt_cnt_of_match);
 234
 235 static struct platform_driver interrupt_cnt_driver = {
 236         .probe = interrupt_cnt_probe,
 237         .driver = {
 238                 .name = INTERRUPT_CNT_NAME,
 239                 .of_match_table = interrupt_cnt_of_match,
 240         },
 241 };
 242 module_platform_driver(interrupt_cnt_driver);
 243
 244 MODULE_ALIAS("platform:interrupt-counter");
 245 MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
 246 MODULE_DESCRIPTION("Interrupt counter driver");
 247 MODULE_LICENSE("GPL v2");