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 hrtimer timer;
  23         struct device        *dev;
  24         wait_queue_head_t     wqueue;
  25
  26         unsigned int    freq;           /* carrier frequency */
  27         unsigned int    duty_cycle;     /* carrier duty cycle */
  28         int             wbuf[WBUF_LEN];
  29         int             wbuf_index;
  30         unsigned long   device_is_open;
  31 };
  32
  33 static inline void ir_rx51_on(struct ir_rx51 *ir_rx51)
  34 {
  35         pwm_enable(ir_rx51->pwm);
  36 }
  37
  38 static inline void ir_rx51_off(struct ir_rx51 *ir_rx51)
  39 {
  40         pwm_disable(ir_rx51->pwm);
  41 }
  42
  43 static int init_timing_params(struct ir_rx51 *ir_rx51)
  44 {
  45         struct pwm_device *pwm = ir_rx51->pwm;
  46         int duty, period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, ir_rx51->freq);
  47
  48         duty = DIV_ROUND_CLOSEST(ir_rx51->duty_cycle * period, 100);
  49
  50         pwm_config(pwm, duty, period);
  51
  52         return 0;
  53 }
  54
  55 static enum hrtimer_restart ir_rx51_timer_cb(struct hrtimer *timer)
  56 {
  57         struct ir_rx51 *ir_rx51 = container_of(timer, struct ir_rx51, timer);
  58         ktime_t now;
  59
  60         if (ir_rx51->wbuf_index < 0) {
  61                 dev_err_ratelimited(ir_rx51->dev,
  62                                     "BUG wbuf_index has value of %i\n",
  63                                     ir_rx51->wbuf_index);
  64                 goto end;
  65         }
  66
  67         /*
  68          * If we happen to hit an odd latency spike, loop through the
  69          * pulses until we catch up.
  70          */
  71         do {
  72                 u64 ns;
  73
  74                 if (ir_rx51->wbuf_index >= WBUF_LEN)
  75                         goto end;
  76                 if (ir_rx51->wbuf[ir_rx51->wbuf_index] == -1)
  77                         goto end;
  78
  79                 if (ir_rx51->wbuf_index % 2)
  80                         ir_rx51_off(ir_rx51);
  81                 else
  82                         ir_rx51_on(ir_rx51);
  83
  84                 ns = US_TO_NS(ir_rx51->wbuf[ir_rx51->wbuf_index]);
  85                 hrtimer_add_expires_ns(timer, ns);
  86
  87                 ir_rx51->wbuf_index++;
  88
  89                 now = timer->base->get_time();
  90
  91         } while (hrtimer_get_expires_tv64(timer) < now);
  92
  93         return HRTIMER_RESTART;
  94 end:
  95         /* Stop TX here */
  96         ir_rx51_off(ir_rx51);
  97         ir_rx51->wbuf_index = -1;
  98
  99         wake_up_interruptible(&ir_rx51->wqueue);
 100
 101         return HRTIMER_NORESTART;
 102 }
 103
 104 static int ir_rx51_tx(struct rc_dev *dev, unsigned int *buffer,
 105                       unsigned int count)
 106 {
 107         struct ir_rx51 *ir_rx51 = dev->priv;
 108
 109         if (count > WBUF_LEN)
 110                 return -EINVAL;
 111
 112         memcpy(ir_rx51->wbuf, buffer, count * sizeof(unsigned int));
 113
 114         /* Wait any pending transfers to finish */
 115         wait_event_interruptible(ir_rx51->wqueue, ir_rx51->wbuf_index < 0);
 116
 117         init_timing_params(ir_rx51);
 118         if (count < WBUF_LEN)
 119                 ir_rx51->wbuf[count] = -1; /* Insert termination mark */
 120
 121         /*
 122          * REVISIT: Adjust latency requirements so the device doesn't go in too
 123          * deep sleep states with pm_qos_add_request().
 124          */
 125
 126         ir_rx51_on(ir_rx51);
 127         ir_rx51->wbuf_index = 1;
 128         hrtimer_start(&ir_rx51->timer,
 129                       ns_to_ktime(US_TO_NS(ir_rx51->wbuf[0])),
 130                       HRTIMER_MODE_REL);
 131         /*
 132          * Don't return back to the userspace until the transfer has
 133          * finished
 134          */
 135         wait_event_interruptible(ir_rx51->wqueue, ir_rx51->wbuf_index < 0);
 136
 137         /* REVISIT: Remove pm_qos constraint, we can sleep again */
 138
 139         return count;
 140 }
 141
 142 static int ir_rx51_open(struct rc_dev *dev)
 143 {
 144         struct ir_rx51 *ir_rx51 = dev->priv;
 145
 146         if (test_and_set_bit(1, &ir_rx51->device_is_open))
 147                 return -EBUSY;
 148
 149         ir_rx51->pwm = pwm_get(ir_rx51->dev, NULL);
 150         if (IS_ERR(ir_rx51->pwm)) {
 151                 int res = PTR_ERR(ir_rx51->pwm);
 152
 153                 dev_err(ir_rx51->dev, "pwm_get failed: %d\n", res);
 154                 return res;
 155         }
 156
 157         return 0;
 158 }
 159
 160 static void ir_rx51_release(struct rc_dev *dev)
 161 {
 162         struct ir_rx51 *ir_rx51 = dev->priv;
 163
 164         hrtimer_cancel(&ir_rx51->timer);
 165         ir_rx51_off(ir_rx51);
 166         pwm_put(ir_rx51->pwm);
 167
 168         clear_bit(1, &ir_rx51->device_is_open);
 169 }
 170
 171 static struct ir_rx51 ir_rx51 = {
 172         .duty_cycle     = 50,
 173         .wbuf_index     = -1,
 174 };
 175
 176 static int ir_rx51_set_duty_cycle(struct rc_dev *dev, u32 duty)
 177 {
 178         struct ir_rx51 *ir_rx51 = dev->priv;
 179
 180         ir_rx51->duty_cycle = duty;
 181
 182         return 0;
 183 }
 184
 185 static int ir_rx51_set_tx_carrier(struct rc_dev *dev, u32 carrier)
 186 {
 187         struct ir_rx51 *ir_rx51 = dev->priv;
 188
 189         if (carrier > 500000 || carrier < 20000)
 190                 return -EINVAL;
 191
 192         ir_rx51->freq = carrier;
 193
 194         return 0;
 195 }
 196
 197 #ifdef CONFIG_PM
 198
 199 static int ir_rx51_suspend(struct platform_device *dev, pm_message_t state)
 200 {
 201         /*
 202          * In case the device is still open, do not suspend. Normally
 203          * this should not be a problem as lircd only keeps the device
 204          * open only for short periods of time. We also don't want to
 205          * get involved with race conditions that might happen if we
 206          * were in a middle of a transmit. Thus, we defer any suspend
 207          * actions until transmit has completed.
 208          */
 209         if (test_and_set_bit(1, &ir_rx51.device_is_open))
 210                 return -EAGAIN;
 211
 212         clear_bit(1, &ir_rx51.device_is_open);
 213
 214         return 0;
 215 }
 216
 217 static int ir_rx51_resume(struct platform_device *dev)
 218 {
 219         return 0;
 220 }
 221
 222 #else
 223
 224 #define ir_rx51_suspend NULL
 225 #define ir_rx51_resume  NULL
 226
 227 #endif /* CONFIG_PM */
 228
 229 static int ir_rx51_probe(struct platform_device *dev)
 230 {
 231         struct pwm_device *pwm;
 232         struct rc_dev *rcdev;
 233
 234         pwm = pwm_get(&dev->dev, NULL);
 235         if (IS_ERR(pwm)) {
 236                 int err = PTR_ERR(pwm);
 237
 238                 if (err != -EPROBE_DEFER)
 239                         dev_err(&dev->dev, "pwm_get failed: %d\n", err);
 240                 return err;
 241         }
 242
 243         /* Use default, in case userspace does not set the carrier */
 244         ir_rx51.freq = DIV_ROUND_CLOSEST_ULL(pwm_get_period(pwm), NSEC_PER_SEC);
 245         pwm_put(pwm);
 246
 247         hrtimer_init(&ir_rx51.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 248         ir_rx51.timer.function = ir_rx51_timer_cb;
 249
 250         ir_rx51.dev = &dev->dev;
 251
 252         rcdev = devm_rc_allocate_device(&dev->dev, RC_DRIVER_IR_RAW_TX);
 253         if (!rcdev)
 254                 return -ENOMEM;
 255
 256         rcdev->priv = &ir_rx51;
 257         rcdev->open = ir_rx51_open;
 258         rcdev->close = ir_rx51_release;
 259         rcdev->tx_ir = ir_rx51_tx;
 260         rcdev->s_tx_duty_cycle = ir_rx51_set_duty_cycle;
 261         rcdev->s_tx_carrier = ir_rx51_set_tx_carrier;
 262         rcdev->driver_name = KBUILD_MODNAME;
 263
 264         ir_rx51.rcdev = rcdev;
 265
 266         return devm_rc_register_device(&dev->dev, ir_rx51.rcdev);
 267 }
 268
 269 static int ir_rx51_remove(struct platform_device *dev)
 270 {
 271         return 0;
 272 }
 273
 274 static const struct of_device_id ir_rx51_match[] = {
 275         {
 276                 .compatible = "nokia,n900-ir",
 277         },
 278         {},
 279 };
 280 MODULE_DEVICE_TABLE(of, ir_rx51_match);
 281
 282 static struct platform_driver ir_rx51_platform_driver = {
 283         .probe          = ir_rx51_probe,
 284         .remove         = ir_rx51_remove,
 285         .suspend        = ir_rx51_suspend,
 286         .resume         = ir_rx51_resume,
 287         .driver         = {
 288                 .name   = KBUILD_MODNAME,
 289                 .of_match_table = of_match_ptr(ir_rx51_match),
 290         },
 291 };
 292 module_platform_driver(ir_rx51_platform_driver);
 293
 294 MODULE_DESCRIPTION("IR TX driver for Nokia RX51");
 295 MODULE_AUTHOR("Nokia Corporation");
 296 MODULE_LICENSE("GPL");