drivers/staging/iio/trigger/iio-trig-bfin-timer.c

   1 /*
   2  * Copyright 2011 Analog Devices Inc.
   3  *
   4  * Licensed under the GPL-2.
   5  *
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/slab.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/irq.h>
  14 #include <linux/delay.h>
  15
  16 #include <asm/gptimers.h>
  17 #include <asm/portmux.h>
  18
  19 #include <linux/iio/iio.h>
  20 #include <linux/iio/trigger.h>
  21
  22 #include "iio-trig-bfin-timer.h"
  23
  24 struct bfin_timer {
  25         unsigned short id, bit;
  26         unsigned long irqbit;
  27         int irq;
  28         int pin;
  29 };
  30
  31 /*
  32  * this covers all hardware timer configurations on
  33  * all Blackfin derivatives out there today
  34  */
  35
  36 static struct bfin_timer iio_bfin_timer_code[MAX_BLACKFIN_GPTIMERS] = {
  37         {TIMER0_id,  TIMER0bit,  TIMER_STATUS_TIMIL0,  IRQ_TIMER0, P_TMR0},
  38         {TIMER1_id,  TIMER1bit,  TIMER_STATUS_TIMIL1,  IRQ_TIMER1, P_TMR1},
  39         {TIMER2_id,  TIMER2bit,  TIMER_STATUS_TIMIL2,  IRQ_TIMER2, P_TMR2},
  40 #if (MAX_BLACKFIN_GPTIMERS > 3)
  41         {TIMER3_id,  TIMER3bit,  TIMER_STATUS_TIMIL3,  IRQ_TIMER3, P_TMR3},
  42         {TIMER4_id,  TIMER4bit,  TIMER_STATUS_TIMIL4,  IRQ_TIMER4, P_TMR4},
  43         {TIMER5_id,  TIMER5bit,  TIMER_STATUS_TIMIL5,  IRQ_TIMER5, P_TMR5},
  44         {TIMER6_id,  TIMER6bit,  TIMER_STATUS_TIMIL6,  IRQ_TIMER6, P_TMR6},
  45         {TIMER7_id,  TIMER7bit,  TIMER_STATUS_TIMIL7,  IRQ_TIMER7, P_TMR7},
  46 #endif
  47 #if (MAX_BLACKFIN_GPTIMERS > 8)
  48         {TIMER8_id,  TIMER8bit,  TIMER_STATUS_TIMIL8,  IRQ_TIMER8, P_TMR8},
  49         {TIMER9_id,  TIMER9bit,  TIMER_STATUS_TIMIL9,  IRQ_TIMER9, P_TMR9},
  50         {TIMER10_id, TIMER10bit, TIMER_STATUS_TIMIL10, IRQ_TIMER10, P_TMR10},
  51 #if (MAX_BLACKFIN_GPTIMERS > 11)
  52         {TIMER11_id, TIMER11bit, TIMER_STATUS_TIMIL11, IRQ_TIMER11, P_TMR11},
  53 #endif
  54 #endif
  55 };
  56
  57 struct bfin_tmr_state {
  58         struct iio_trigger *trig;
  59         struct bfin_timer *t;
  60         unsigned timer_num;
  61         bool output_enable;
  62         unsigned int duty;
  63         int irq;
  64 };
  65
  66 static int iio_bfin_tmr_set_state(struct iio_trigger *trig, bool state)
  67 {
  68         struct bfin_tmr_state *st = iio_trigger_get_drvdata(trig);
  69
  70         if (get_gptimer_period(st->t->id) == 0)
  71                 return -EINVAL;
  72
  73         if (state)
  74                 enable_gptimers(st->t->bit);
  75         else
  76                 disable_gptimers(st->t->bit);
  77
  78         return 0;
  79 }
  80
  81 static ssize_t iio_bfin_tmr_frequency_store(struct device *dev,
  82                 struct device_attribute *attr, const char *buf, size_t count)
  83 {
  84         struct iio_trigger *trig = to_iio_trigger(dev);
  85         struct bfin_tmr_state *st = iio_trigger_get_drvdata(trig);
  86         unsigned long val;
  87         bool enabled;
  88         int ret;
  89
  90         ret = strict_strtoul(buf, 10, &val);
  91         if (ret)
  92                 goto error_ret;
  93
  94         if (val > 100000) {
  95                 ret = -EINVAL;
  96                 goto error_ret;
  97         }
  98
  99         enabled = get_enabled_gptimers() & st->t->bit;
 100
 101         if (enabled)
 102                 disable_gptimers(st->t->bit);
 103
 104         if (!val)
 105                 goto error_ret;
 106
 107         val = get_sclk() / val;
 108         if (val <= 4 || val <= st->duty) {
 109                 ret = -EINVAL;
 110                 goto error_ret;
 111         }
 112
 113         set_gptimer_period(st->t->id, val);
 114         set_gptimer_pwidth(st->t->id, val - st->duty);
 115
 116         if (enabled)
 117                 enable_gptimers(st->t->bit);
 118
 119 error_ret:
 120         return ret ? ret : count;
 121 }
 122
 123 static ssize_t iio_bfin_tmr_frequency_show(struct device *dev,
 124                                  struct device_attribute *attr,
 125                                  char *buf)
 126 {
 127         struct iio_trigger *trig = to_iio_trigger(dev);
 128         struct bfin_tmr_state *st = iio_trigger_get_drvdata(trig);
 129         unsigned int period = get_gptimer_period(st->t->id);
 130         unsigned long val;
 131
 132         if (period == 0)
 133                 val = 0;
 134         else
 135                 val = get_sclk() / get_gptimer_period(st->t->id);
 136
 137         return sprintf(buf, "%lu\n", val);
 138 }
 139
 140 static DEVICE_ATTR(frequency, S_IRUGO | S_IWUSR, iio_bfin_tmr_frequency_show,
 141                    iio_bfin_tmr_frequency_store);
 142
 143 static struct attribute *iio_bfin_tmr_trigger_attrs[] = {
 144         &dev_attr_frequency.attr,
 145         NULL,
 146 };
 147
 148 static const struct attribute_group iio_bfin_tmr_trigger_attr_group = {
 149         .attrs = iio_bfin_tmr_trigger_attrs,
 150 };
 151
 152 static const struct attribute_group *iio_bfin_tmr_trigger_attr_groups[] = {
 153         &iio_bfin_tmr_trigger_attr_group,
 154         NULL
 155 };
 156
 157 static irqreturn_t iio_bfin_tmr_trigger_isr(int irq, void *devid)
 158 {
 159         struct bfin_tmr_state *st = devid;
 160
 161         clear_gptimer_intr(st->t->id);
 162         iio_trigger_poll(st->trig, 0);
 163
 164         return IRQ_HANDLED;
 165 }
 166
 167 static int iio_bfin_tmr_get_number(int irq)
 168 {
 169         int i;
 170
 171         for (i = 0; i < MAX_BLACKFIN_GPTIMERS; i++)
 172                 if (iio_bfin_timer_code[i].irq == irq)
 173                         return i;
 174
 175         return -ENODEV;
 176 }
 177
 178 static const struct iio_trigger_ops iio_bfin_tmr_trigger_ops = {
 179         .owner = THIS_MODULE,
 180         .set_trigger_state = iio_bfin_tmr_set_state,
 181 };
 182
 183 static int iio_bfin_tmr_trigger_probe(struct platform_device *pdev)
 184 {
 185         struct iio_bfin_timer_trigger_pdata *pdata = pdev->dev.platform_data;
 186         struct bfin_tmr_state *st;
 187         unsigned int config;
 188         int ret;
 189
 190         st = kzalloc(sizeof(*st), GFP_KERNEL);
 191         if (st == NULL) {
 192                 ret = -ENOMEM;
 193                 goto out;
 194         }
 195
 196         st->irq = platform_get_irq(pdev, 0);
 197         if (!st->irq) {
 198                 dev_err(&pdev->dev, "No IRQs specified");
 199                 ret = -ENODEV;
 200                 goto out1;
 201         }
 202
 203         ret = iio_bfin_tmr_get_number(st->irq);
 204         if (ret < 0)
 205                 goto out1;
 206
 207         st->timer_num = ret;
 208         st->t = &iio_bfin_timer_code[st->timer_num];
 209
 210         st->trig = iio_trigger_alloc("bfintmr%d", st->timer_num);
 211         if (!st->trig) {
 212                 ret = -ENOMEM;
 213                 goto out1;
 214         }
 215
 216         st->trig->ops = &iio_bfin_tmr_trigger_ops;
 217         st->trig->dev.groups = iio_bfin_tmr_trigger_attr_groups;
 218         iio_trigger_set_drvdata(st->trig, st);
 219         ret = iio_trigger_register(st->trig);
 220         if (ret)
 221                 goto out2;
 222
 223         ret = request_irq(st->irq, iio_bfin_tmr_trigger_isr,
 224                           0, st->trig->name, st);
 225         if (ret) {
 226                 dev_err(&pdev->dev,
 227                         "request IRQ-%d failed", st->irq);
 228                 goto out4;
 229         }
 230
 231         config = PWM_OUT | PERIOD_CNT | IRQ_ENA;
 232
 233         if (pdata && pdata->output_enable) {
 234                 unsigned long long val;
 235
 236                 st->output_enable = true;
 237
 238                 ret = peripheral_request(st->t->pin, st->trig->name);
 239                 if (ret)
 240                         goto out_free_irq;
 241
 242                 val = (unsigned long long)get_sclk() * pdata->duty_ns;
 243                 do_div(val, NSEC_PER_SEC);
 244                 st->duty = val;
 245
 246                 /**
 247                  * The interrupt will be generated at the end of the period,
 248                  * since we want the interrupt to be generated at end of the
 249                  * pulse we invert both polarity and duty cycle, so that the
 250                  * pulse will be generated directly before the interrupt.
 251                  */
 252                 if (pdata->active_low)
 253                         config |= PULSE_HI;
 254         } else {
 255                 st->duty = 1;
 256                 config |= OUT_DIS;
 257         }
 258
 259         set_gptimer_config(st->t->id, config);
 260
 261         dev_info(&pdev->dev, "iio trigger Blackfin TMR%d, IRQ-%d",
 262                  st->timer_num, st->irq);
 263         platform_set_drvdata(pdev, st);
 264
 265         return 0;
 266 out_free_irq:
 267         free_irq(st->irq, st);
 268 out4:
 269         iio_trigger_unregister(st->trig);
 270 out2:
 271         iio_trigger_put(st->trig);
 272 out1:
 273         kfree(st);
 274 out:
 275         return ret;
 276 }
 277
 278 static int iio_bfin_tmr_trigger_remove(struct platform_device *pdev)
 279 {
 280         struct bfin_tmr_state *st = platform_get_drvdata(pdev);
 281
 282         disable_gptimers(st->t->bit);
 283         if (st->output_enable)
 284                 peripheral_free(st->t->pin);
 285         free_irq(st->irq, st);
 286         iio_trigger_unregister(st->trig);
 287         iio_trigger_put(st->trig);
 288         kfree(st);
 289
 290         return 0;
 291 }
 292
 293 static struct platform_driver iio_bfin_tmr_trigger_driver = {
 294         .driver = {
 295                 .name = "iio_bfin_tmr_trigger",
 296                 .owner = THIS_MODULE,
 297         },
 298         .probe = iio_bfin_tmr_trigger_probe,
 299         .remove = iio_bfin_tmr_trigger_remove,
 300 };
 301
 302 module_platform_driver(iio_bfin_tmr_trigger_driver);
 303
 304 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 305 MODULE_DESCRIPTION("Blackfin system timer based trigger for the iio subsystem");
 306 MODULE_LICENSE("GPL v2");
 307 MODULE_ALIAS("platform:iio-trig-bfin-timer");