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