drivers/media/rc/ir-rx51.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Copyright (C) 2008 Nokia Corporation
   4  *
   5  *  Based on lirc_serial.c
   6  */
   7 #include <linux/clk.h>
   8 #include <linux/module.h>
   9 #include <linux/platform_device.h>
  10 #include <linux/wait.h>
  11 #include <linux/pwm.h>
  12 #include <linux/of.h>
  13 #include <linux/hrtimer.h>
  14
  15 #include <media/rc-core.h>
  16
  17 #define WBUF_LEN 256
  18
  19 struct ir_rx51 {
  20         struct rc_dev *rcdev;
  21         struct pwm_device *pwm;
  22         struct pwm_state state;
  23         struct hrtimer timer;
  24         struct device        *dev;
  25         wait_queue_head_t     wqueue;
  26
  27         unsigned int    freq;           /* carrier frequency */
  28         unsigned int    duty_cycle;     /* carrier duty cycle */
  29         int             wbuf[WBUF_LEN];
  30         int             wbuf_index;
  31         unsigned long   device_is_open;
  32 };
  33
  34 static inline void ir_rx51_on(struct ir_rx51 *ir_rx51)
  35 {
  36         ir_rx51->state.enabled = true;
  37         pwm_apply_state(ir_rx51->pwm, &ir_rx51->state);
  38 }
  39
  40 static inline void ir_rx51_off(struct ir_rx51 *ir_rx51)
  41 {
  42         ir_rx51->state.enabled = false;
  43         pwm_apply_state(ir_rx51->pwm, &ir_rx51->state);
  44 }
  45
  46 static int init_timing_params(struct ir_rx51 *ir_rx51)
  47 {
  48         ir_rx51->state.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, ir_rx51->freq);
  49         pwm_set_relative_duty_cycle(&ir_rx51->state, ir_rx51->duty_cycle, 100);
  50
  51         return 0;
  52 }
  53
  54 static enum hrtimer_restart ir_rx51_timer_cb(struct hrtimer *timer)
  55 {
  56         struct ir_rx51 *ir_rx51 = container_of(timer, struct ir_rx51, timer);
  57         ktime_t now;
  58
  59         if (ir_rx51->wbuf_index < 0) {
  60                 dev_err_ratelimited(ir_rx51->dev,
  61                                     "BUG wbuf_index has value of %i\n",
  62                                     ir_rx51->wbuf_index);
  63                 goto end;
  64         }
  65
  66         /*
  67          * If we happen to hit an odd latency spike, loop through the
  68          * pulses until we catch up.
  69          */
  70         do {
  71                 u64 ns;
  72
  73                 if (ir_rx51->wbuf_index >= WBUF_LEN)
  74                         goto end;
  75                 if (ir_rx51->wbuf[ir_rx51->wbuf_index] == -1)
  76                         goto end;
  77
  78                 if (ir_rx51->wbuf_index % 2)
  79                         ir_rx51_off(ir_rx51);
  80                 else
  81                         ir_rx51_on(ir_rx51);
  82
  83                 ns = US_TO_NS(ir_rx51->wbuf[ir_rx51->wbuf_index]);
  84                 hrtimer_add_expires_ns(timer, ns);
  85
  86                 ir_rx51->wbuf_index++;
  87
  88                 now = timer->base->get_time();
  89
  90         } while (hrtimer_get_expires_tv64(timer) < now);
  91
  92         return HRTIMER_RESTART;
  93 end:
  94         /* Stop TX here */
  95         ir_rx51_off(ir_rx51);
  96         ir_rx51->wbuf_index = -1;
  97
  98         wake_up_interruptible(&ir_rx51->wqueue);
  99
 100         return HRTIMER_NORESTART;
 101 }
 102
 103 static int ir_rx51_tx(struct rc_dev *dev, unsigned int *buffer,
 104                       unsigned int count)
 105 {
 106         struct ir_rx51 *ir_rx51 = dev->priv;
 107
 108         if (count > WBUF_LEN)
 109                 return -EINVAL;
 110
 111         memcpy(ir_rx51->wbuf, buffer, count * sizeof(unsigned int));
 112
 113         /* Wait any pending transfers to finish */
 114         wait_event_interruptible(ir_rx51->wqueue, ir_rx51->wbuf_index < 0);
 115
 116         init_timing_params(ir_rx51);
 117         if (count < WBUF_LEN)
 118                 ir_rx51->wbuf[count] = -1; /* Insert termination mark */
 119
 120         /*
 121          * REVISIT: Adjust latency requirements so the device doesn't go in too
 122          * deep sleep states with pm_qos_add_request().
 123          */
 124
 125         ir_rx51_on(ir_rx51);
 126         ir_rx51->wbuf_index = 1;
 127         hrtimer_start(&ir_rx51->timer,
 128                       ns_to_ktime(US_TO_NS(ir_rx51->wbuf[0])),
 129                       HRTIMER_MODE_REL);
 130         /*
 131          * Don't return back to the userspace until the transfer has
 132          * finished
 133          */
 134         wait_event_interruptible(ir_rx51->wqueue, ir_rx51->wbuf_index < 0);
 135
 136         /* REVISIT: Remove pm_qos constraint, we can sleep again */
 137
 138         return count;
 139 }
 140
 141 static int ir_rx51_open(struct rc_dev *dev)
 142 {
 143         struct ir_rx51 *ir_rx51 = dev->priv;
 144
 145         if (test_and_set_bit(1, &ir_rx51->device_is_open))
 146                 return -EBUSY;
 147
 148         ir_rx51->pwm = pwm_get(ir_rx51->dev, NULL);
 149         if (IS_ERR(ir_rx51->pwm)) {
 150                 int res = PTR_ERR(ir_rx51->pwm);
 151
 152                 dev_err(ir_rx51->dev, "pwm_get failed: %d\n", res);
 153                 return res;
 154         }
 155
 156         return 0;
 157 }
 158
 159 static void ir_rx51_release(struct rc_dev *dev)
 160 {
 161         struct ir_rx51 *ir_rx51 = dev->priv;
 162
 163         hrtimer_cancel(&ir_rx51->timer);
 164         ir_rx51_off(ir_rx51);
 165         pwm_put(ir_rx51->pwm);
 166
 167         clear_bit(1, &ir_rx51->device_is_open);
 168 }
 169
 170 static struct ir_rx51 ir_rx51 = {
 171         .duty_cycle     = 50,
 172         .wbuf_index     = -1,
 173 };
 174
 175 static int ir_rx51_set_duty_cycle(struct rc_dev *dev, u32 duty)
 176 {
 177         struct ir_rx51 *ir_rx51 = dev->priv;
 178
 179         ir_rx51->duty_cycle = duty;
 180
 181         return 0;
 182 }
 183
 184 static int ir_rx51_set_tx_carrier(struct rc_dev *dev, u32 carrier)
 185 {
 186         struct ir_rx51 *ir_rx51 = dev->priv;
 187
 188         if (carrier > 500000 || carrier < 20000)
 189                 return -EINVAL;
 190
 191         ir_rx51->freq = carrier;
 192
 193         return 0;
 194 }
 195
 196 #ifdef CONFIG_PM
 197
 198 static int ir_rx51_suspend(struct platform_device *dev, pm_message_t state)
 199 {
 200         /*
 201          * In case the device is still open, do not suspend. Normally
 202          * this should not be a problem as lircd only keeps the device
 203          * open only for short periods of time. We also don't want to
 204          * get involved with race conditions that might happen if we
 205          * were in a middle of a transmit. Thus, we defer any suspend
 206          * actions until transmit has completed.
 207          */
 208         if (test_and_set_bit(1, &ir_rx51.device_is_open))
 209                 return -EAGAIN;
 210
 211         clear_bit(1, &ir_rx51.device_is_open);
 212
 213         return 0;
 214 }
 215
 216 static int ir_rx51_resume(struct platform_device *dev)
 217 {
 218         return 0;
 219 }
 220
 221 #else
 222
 223 #define ir_rx51_suspend NULL
 224 #define ir_rx51_resume  NULL
 225
 226 #endif /* CONFIG_PM */
 227
 228 static int ir_rx51_probe(struct platform_device *dev)
 229 {
 230         struct pwm_device *pwm;
 231         struct rc_dev *rcdev;
 232
 233         pwm = pwm_get(&dev->dev, NULL);
 234         if (IS_ERR(pwm))
 235                 return dev_err_probe(&dev->dev, PTR_ERR(pwm), "pwm_get failed\n");
 236
 237         /* Use default, in case userspace does not set the carrier */
 238         ir_rx51.freq = DIV_ROUND_CLOSEST_ULL(pwm_get_period(pwm), NSEC_PER_SEC);
 239         pwm_init_state(pwm, &ir_rx51.state);
 240         pwm_put(pwm);
 241
 242         hrtimer_init(&ir_rx51.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 243         ir_rx51.timer.function = ir_rx51_timer_cb;
 244
 245         ir_rx51.dev = &dev->dev;
 246
 247         rcdev = devm_rc_allocate_device(&dev->dev, RC_DRIVER_IR_RAW_TX);
 248         if (!rcdev)
 249                 return -ENOMEM;
 250
 251         rcdev->priv = &ir_rx51;
 252         rcdev->open = ir_rx51_open;
 253         rcdev->close = ir_rx51_release;
 254         rcdev->tx_ir = ir_rx51_tx;
 255         rcdev->s_tx_duty_cycle = ir_rx51_set_duty_cycle;
 256         rcdev->s_tx_carrier = ir_rx51_set_tx_carrier;
 257         rcdev->driver_name = KBUILD_MODNAME;
 258
 259         ir_rx51.rcdev = rcdev;
 260
 261         return devm_rc_register_device(&dev->dev, ir_rx51.rcdev);
 262 }
 263
 264 static const struct of_device_id ir_rx51_match[] = {
 265         {
 266                 .compatible = "nokia,n900-ir",
 267         },
 268         {},
 269 };
 270 MODULE_DEVICE_TABLE(of, ir_rx51_match);
 271
 272 static struct platform_driver ir_rx51_platform_driver = {
 273         .probe          = ir_rx51_probe,
 274         .suspend        = ir_rx51_suspend,
 275         .resume         = ir_rx51_resume,
 276         .driver         = {
 277                 .name   = KBUILD_MODNAME,
 278                 .of_match_table = of_match_ptr(ir_rx51_match),
 279         },
 280 };
 281 module_platform_driver(ir_rx51_platform_driver);
 282
 283 MODULE_DESCRIPTION("IR TX driver for Nokia RX51");
 284 MODULE_AUTHOR("Nokia Corporation");
 285 MODULE_LICENSE("GPL");