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