drivers/media/rc/ir-rx51.c

   1 /*
   2  *  Copyright (C) 2008 Nokia Corporation
   3  *
   4  *  Based on lirc_serial.c
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  */
  16 #include <linux/clk.h>
  17 #include <linux/module.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/wait.h>
  20 #include <linux/pwm.h>
  21 #include <linux/of.h>
  22 #include <linux/hrtimer.h>
  23
  24 #include <media/rc-core.h>
  25
  26 #define WBUF_LEN 256
  27
  28 struct ir_rx51 {
  29         struct rc_dev *rcdev;
  30         struct pwm_device *pwm;
  31         struct hrtimer timer;
  32         struct device        *dev;
  33         wait_queue_head_t     wqueue;
  34
  35         unsigned int    freq;           /* carrier frequency */
  36         unsigned int    duty_cycle;     /* carrier duty cycle */
  37         int             wbuf[WBUF_LEN];
  38         int             wbuf_index;
  39         unsigned long   device_is_open;
  40 };
  41
  42 static inline void ir_rx51_on(struct ir_rx51 *ir_rx51)
  43 {
  44         pwm_enable(ir_rx51->pwm);
  45 }
  46
  47 static inline void ir_rx51_off(struct ir_rx51 *ir_rx51)
  48 {
  49         pwm_disable(ir_rx51->pwm);
  50 }
  51
  52 static int init_timing_params(struct ir_rx51 *ir_rx51)
  53 {
  54         struct pwm_device *pwm = ir_rx51->pwm;
  55         int duty, period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, ir_rx51->freq);
  56
  57         duty = DIV_ROUND_CLOSEST(ir_rx51->duty_cycle * period, 100);
  58
  59         pwm_config(pwm, duty, period);
  60
  61         return 0;
  62 }
  63
  64 static enum hrtimer_restart ir_rx51_timer_cb(struct hrtimer *timer)
  65 {
  66         struct ir_rx51 *ir_rx51 = container_of(timer, struct ir_rx51, timer);
  67         ktime_t now;
  68
  69         if (ir_rx51->wbuf_index < 0) {
  70                 dev_err_ratelimited(ir_rx51->dev,
  71                                     "BUG wbuf_index has value of %i\n",
  72                                     ir_rx51->wbuf_index);
  73                 goto end;
  74         }
  75
  76         /*
  77          * If we happen to hit an odd latency spike, loop through the
  78          * pulses until we catch up.
  79          */
  80         do {
  81                 u64 ns;
  82
  83                 if (ir_rx51->wbuf_index >= WBUF_LEN)
  84                         goto end;
  85                 if (ir_rx51->wbuf[ir_rx51->wbuf_index] == -1)
  86                         goto end;
  87
  88                 if (ir_rx51->wbuf_index % 2)
  89                         ir_rx51_off(ir_rx51);
  90                 else
  91                         ir_rx51_on(ir_rx51);
  92
  93                 ns = US_TO_NS(ir_rx51->wbuf[ir_rx51->wbuf_index]);
  94                 hrtimer_add_expires_ns(timer, ns);
  95
  96                 ir_rx51->wbuf_index++;
  97
  98                 now = timer->base->get_time();
  99
 100         } while (hrtimer_get_expires_tv64(timer) < now);
 101
 102         return HRTIMER_RESTART;
 103 end:
 104         /* Stop TX here */
 105         ir_rx51_off(ir_rx51);
 106         ir_rx51->wbuf_index = -1;
 107
 108         wake_up_interruptible(&ir_rx51->wqueue);
 109
 110         return HRTIMER_NORESTART;
 111 }
 112
 113 static int ir_rx51_tx(struct rc_dev *dev, unsigned int *buffer,
 114                       unsigned int count)
 115 {
 116         struct ir_rx51 *ir_rx51 = dev->priv;
 117
 118         if (count > WBUF_LEN)
 119                 return -EINVAL;
 120
 121         memcpy(ir_rx51->wbuf, buffer, count * sizeof(unsigned int));
 122
 123         /* Wait any pending transfers to finish */
 124         wait_event_interruptible(ir_rx51->wqueue, ir_rx51->wbuf_index < 0);
 125
 126         init_timing_params(ir_rx51);
 127         if (count < WBUF_LEN)
 128                 ir_rx51->wbuf[count] = -1; /* Insert termination mark */
 129
 130         /*
 131          * REVISIT: Adjust latency requirements so the device doesn't go in too
 132          * deep sleep states with pm_qos_add_request().
 133          */
 134
 135         ir_rx51_on(ir_rx51);
 136         ir_rx51->wbuf_index = 1;
 137         hrtimer_start(&ir_rx51->timer,
 138                       ns_to_ktime(US_TO_NS(ir_rx51->wbuf[0])),
 139                       HRTIMER_MODE_REL);
 140         /*
 141          * Don't return back to the userspace until the transfer has
 142          * finished
 143          */
 144         wait_event_interruptible(ir_rx51->wqueue, ir_rx51->wbuf_index < 0);
 145
 146         /* REVISIT: Remove pm_qos constraint, we can sleep again */
 147
 148         return count;
 149 }
 150
 151 static int ir_rx51_open(struct rc_dev *dev)
 152 {
 153         struct ir_rx51 *ir_rx51 = dev->priv;
 154
 155         if (test_and_set_bit(1, &ir_rx51->device_is_open))
 156                 return -EBUSY;
 157
 158         ir_rx51->pwm = pwm_get(ir_rx51->dev, NULL);
 159         if (IS_ERR(ir_rx51->pwm)) {
 160                 int res = PTR_ERR(ir_rx51->pwm);
 161
 162                 dev_err(ir_rx51->dev, "pwm_get failed: %d\n", res);
 163                 return res;
 164         }
 165
 166         return 0;
 167 }
 168
 169 static void ir_rx51_release(struct rc_dev *dev)
 170 {
 171         struct ir_rx51 *ir_rx51 = dev->priv;
 172
 173         hrtimer_cancel(&ir_rx51->timer);
 174         ir_rx51_off(ir_rx51);
 175         pwm_put(ir_rx51->pwm);
 176
 177         clear_bit(1, &ir_rx51->device_is_open);
 178 }
 179
 180 static struct ir_rx51 ir_rx51 = {
 181         .duty_cycle     = 50,
 182         .wbuf_index     = -1,
 183 };
 184
 185 static int ir_rx51_set_duty_cycle(struct rc_dev *dev, u32 duty)
 186 {
 187         struct ir_rx51 *ir_rx51 = dev->priv;
 188
 189         ir_rx51->duty_cycle = duty;
 190
 191         return 0;
 192 }
 193
 194 static int ir_rx51_set_tx_carrier(struct rc_dev *dev, u32 carrier)
 195 {
 196         struct ir_rx51 *ir_rx51 = dev->priv;
 197
 198         if (carrier > 500000 || carrier < 20000)
 199                 return -EINVAL;
 200
 201         ir_rx51->freq = carrier;
 202
 203         return 0;
 204 }
 205
 206 #ifdef CONFIG_PM
 207
 208 static int ir_rx51_suspend(struct platform_device *dev, pm_message_t state)
 209 {
 210         /*
 211          * In case the device is still open, do not suspend. Normally
 212          * this should not be a problem as lircd only keeps the device
 213          * open only for short periods of time. We also don't want to
 214          * get involved with race conditions that might happen if we
 215          * were in a middle of a transmit. Thus, we defer any suspend
 216          * actions until transmit has completed.
 217          */
 218         if (test_and_set_bit(1, &ir_rx51.device_is_open))
 219                 return -EAGAIN;
 220
 221         clear_bit(1, &ir_rx51.device_is_open);
 222
 223         return 0;
 224 }
 225
 226 static int ir_rx51_resume(struct platform_device *dev)
 227 {
 228         return 0;
 229 }
 230
 231 #else
 232
 233 #define ir_rx51_suspend NULL
 234 #define ir_rx51_resume  NULL
 235
 236 #endif /* CONFIG_PM */
 237
 238 static int ir_rx51_probe(struct platform_device *dev)
 239 {
 240         struct pwm_device *pwm;
 241         struct rc_dev *rcdev;
 242
 243         pwm = pwm_get(&dev->dev, NULL);
 244         if (IS_ERR(pwm)) {
 245                 int err = PTR_ERR(pwm);
 246
 247                 if (err != -EPROBE_DEFER)
 248                         dev_err(&dev->dev, "pwm_get failed: %d\n", err);
 249                 return err;
 250         }
 251
 252         /* Use default, in case userspace does not set the carrier */
 253         ir_rx51.freq = DIV_ROUND_CLOSEST(pwm_get_period(pwm), NSEC_PER_SEC);
 254         pwm_put(pwm);
 255
 256         hrtimer_init(&ir_rx51.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 257         ir_rx51.timer.function = ir_rx51_timer_cb;
 258
 259         ir_rx51.dev = &dev->dev;
 260
 261         rcdev = devm_rc_allocate_device(&dev->dev, RC_DRIVER_IR_RAW_TX);
 262         if (!rcdev)
 263                 return -ENOMEM;
 264
 265         rcdev->priv = &ir_rx51;
 266         rcdev->open = ir_rx51_open;
 267         rcdev->close = ir_rx51_release;
 268         rcdev->tx_ir = ir_rx51_tx;
 269         rcdev->s_tx_duty_cycle = ir_rx51_set_duty_cycle;
 270         rcdev->s_tx_carrier = ir_rx51_set_tx_carrier;
 271         rcdev->driver_name = KBUILD_MODNAME;
 272
 273         ir_rx51.rcdev = rcdev;
 274
 275         return devm_rc_register_device(&dev->dev, ir_rx51.rcdev);
 276 }
 277
 278 static int ir_rx51_remove(struct platform_device *dev)
 279 {
 280         return 0;
 281 }
 282
 283 static const struct of_device_id ir_rx51_match[] = {
 284         {
 285                 .compatible = "nokia,n900-ir",
 286         },
 287         {},
 288 };
 289 MODULE_DEVICE_TABLE(of, ir_rx51_match);
 290
 291 static struct platform_driver ir_rx51_platform_driver = {
 292         .probe          = ir_rx51_probe,
 293         .remove         = ir_rx51_remove,
 294         .suspend        = ir_rx51_suspend,
 295         .resume         = ir_rx51_resume,
 296         .driver         = {
 297                 .name   = KBUILD_MODNAME,
 298                 .of_match_table = of_match_ptr(ir_rx51_match),
 299         },
 300 };
 301 module_platform_driver(ir_rx51_platform_driver);
 302
 303 MODULE_DESCRIPTION("IR TX driver for Nokia RX51");
 304 MODULE_AUTHOR("Nokia Corporation");
 305 MODULE_LICENSE("GPL");