drivers/mfd/wm831x-auxadc.c

   1 /*
   2  * wm831x-auxadc.c  --  AUXADC for Wolfson WM831x PMICs
   3  *
   4  * Copyright 2009-2011 Wolfson Microelectronics PLC.
   5  *
   6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   7  *
   8  *  This program is free software; you can redistribute  it and/or modify it
   9  *  under  the terms of  the GNU General  Public License as published by the
  10  *  Free Software Foundation;  either version 2 of the  License, or (at your
  11  *  option) any later version.
  12  *
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/delay.h>
  18 #include <linux/mfd/core.h>
  19 #include <linux/slab.h>
  20 #include <linux/list.h>
  21
  22 #include <linux/mfd/wm831x/core.h>
  23 #include <linux/mfd/wm831x/pdata.h>
  24 #include <linux/mfd/wm831x/irq.h>
  25 #include <linux/mfd/wm831x/auxadc.h>
  26 #include <linux/mfd/wm831x/otp.h>
  27 #include <linux/mfd/wm831x/regulator.h>
  28
  29 struct wm831x_auxadc_req {
  30         struct list_head list;
  31         enum wm831x_auxadc input;
  32         int val;
  33         struct completion done;
  34 };
  35
  36 static int wm831x_auxadc_read_irq(struct wm831x *wm831x,
  37                                   enum wm831x_auxadc input)
  38 {
  39         struct wm831x_auxadc_req *req;
  40         int ret;
  41         bool ena = false;
  42
  43         req = kzalloc(sizeof(*req), GFP_KERNEL);
  44         if (!req)
  45                 return -ENOMEM;
  46
  47         init_completion(&req->done);
  48         req->input = input;
  49         req->val = -ETIMEDOUT;
  50
  51         mutex_lock(&wm831x->auxadc_lock);
  52
  53         /* Enqueue the request */
  54         list_add(&req->list, &wm831x->auxadc_pending);
  55
  56         ena = !wm831x->auxadc_active;
  57
  58         if (ena) {
  59                 ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
  60                                       WM831X_AUX_ENA, WM831X_AUX_ENA);
  61                 if (ret != 0) {
  62                         dev_err(wm831x->dev, "Failed to enable AUXADC: %d\n",
  63                                 ret);
  64                         goto out;
  65                 }
  66         }
  67
  68         /* Enable the conversion if not already running */
  69         if (!(wm831x->auxadc_active & (1 << input))) {
  70                 ret = wm831x_set_bits(wm831x, WM831X_AUXADC_SOURCE,
  71                                       1 << input, 1 << input);
  72                 if (ret != 0) {
  73                         dev_err(wm831x->dev,
  74                                 "Failed to set AUXADC source: %d\n", ret);
  75                         goto out;
  76                 }
  77
  78                 wm831x->auxadc_active |= 1 << input;
  79         }
  80
  81         /* We convert at the fastest rate possible */
  82         if (ena) {
  83                 ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
  84                                       WM831X_AUX_CVT_ENA |
  85                                       WM831X_AUX_RATE_MASK,
  86                                       WM831X_AUX_CVT_ENA |
  87                                       WM831X_AUX_RATE_MASK);
  88                 if (ret != 0) {
  89                         dev_err(wm831x->dev, "Failed to start AUXADC: %d\n",
  90                                 ret);
  91                         goto out;
  92                 }
  93         }
  94
  95         mutex_unlock(&wm831x->auxadc_lock);
  96
  97         /* Wait for an interrupt */
  98         wait_for_completion_timeout(&req->done, msecs_to_jiffies(500));
  99
 100         mutex_lock(&wm831x->auxadc_lock);
 101
 102         list_del(&req->list);
 103         ret = req->val;
 104
 105 out:
 106         mutex_unlock(&wm831x->auxadc_lock);
 107
 108         kfree(req);
 109
 110         return ret;
 111 }
 112
 113 static irqreturn_t wm831x_auxadc_irq(int irq, void *irq_data)
 114 {
 115         struct wm831x *wm831x = irq_data;
 116         struct wm831x_auxadc_req *req;
 117         int ret, input, val;
 118
 119         ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
 120         if (ret < 0) {
 121                 dev_err(wm831x->dev,
 122                         "Failed to read AUXADC data: %d\n", ret);
 123                 return IRQ_NONE;
 124         }
 125
 126         input = ((ret & WM831X_AUX_DATA_SRC_MASK)
 127                  >> WM831X_AUX_DATA_SRC_SHIFT) - 1;
 128
 129         if (input == 14)
 130                 input = WM831X_AUX_CAL;
 131
 132         val = ret & WM831X_AUX_DATA_MASK;
 133
 134         mutex_lock(&wm831x->auxadc_lock);
 135
 136         /* Disable this conversion, we're about to complete all users */
 137         wm831x_set_bits(wm831x, WM831X_AUXADC_SOURCE,
 138                         1 << input, 0);
 139         wm831x->auxadc_active &= ~(1 << input);
 140
 141         /* Turn off the entire convertor if idle */
 142         if (!wm831x->auxadc_active)
 143                 wm831x_reg_write(wm831x, WM831X_AUXADC_CONTROL, 0);
 144
 145         /* Wake up any threads waiting for this request */
 146         list_for_each_entry(req, &wm831x->auxadc_pending, list) {
 147                 if (req->input == input) {
 148                         req->val = val;
 149                         complete(&req->done);
 150                 }
 151         }
 152
 153         mutex_unlock(&wm831x->auxadc_lock);
 154
 155         return IRQ_HANDLED;
 156 }
 157
 158 static int wm831x_auxadc_read_polled(struct wm831x *wm831x,
 159                                      enum wm831x_auxadc input)
 160 {
 161         int ret, src, timeout;
 162
 163         mutex_lock(&wm831x->auxadc_lock);
 164
 165         ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
 166                               WM831X_AUX_ENA, WM831X_AUX_ENA);
 167         if (ret < 0) {
 168                 dev_err(wm831x->dev, "Failed to enable AUXADC: %d\n", ret);
 169                 goto out;
 170         }
 171
 172         /* We force a single source at present */
 173         src = input;
 174         ret = wm831x_reg_write(wm831x, WM831X_AUXADC_SOURCE,
 175                                1 << src);
 176         if (ret < 0) {
 177                 dev_err(wm831x->dev, "Failed to set AUXADC source: %d\n", ret);
 178                 goto out;
 179         }
 180
 181         ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
 182                               WM831X_AUX_CVT_ENA, WM831X_AUX_CVT_ENA);
 183         if (ret < 0) {
 184                 dev_err(wm831x->dev, "Failed to start AUXADC: %d\n", ret);
 185                 goto disable;
 186         }
 187
 188         /* If we're not using interrupts then poll the
 189          * interrupt status register */
 190         timeout = 5;
 191         while (timeout) {
 192                 msleep(1);
 193
 194                 ret = wm831x_reg_read(wm831x,
 195                                       WM831X_INTERRUPT_STATUS_1);
 196                 if (ret < 0) {
 197                         dev_err(wm831x->dev,
 198                                 "ISR 1 read failed: %d\n", ret);
 199                         goto disable;
 200                 }
 201
 202                 /* Did it complete? */
 203                 if (ret & WM831X_AUXADC_DATA_EINT) {
 204                         wm831x_reg_write(wm831x,
 205                                          WM831X_INTERRUPT_STATUS_1,
 206                                          WM831X_AUXADC_DATA_EINT);
 207                         break;
 208                 } else {
 209                         dev_err(wm831x->dev,
 210                                 "AUXADC conversion timeout\n");
 211                         ret = -EBUSY;
 212                         goto disable;
 213                 }
 214         }
 215
 216         ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
 217         if (ret < 0) {
 218                 dev_err(wm831x->dev,
 219                         "Failed to read AUXADC data: %d\n", ret);
 220                 goto disable;
 221         }
 222
 223         src = ((ret & WM831X_AUX_DATA_SRC_MASK)
 224                >> WM831X_AUX_DATA_SRC_SHIFT) - 1;
 225
 226         if (src == 14)
 227                 src = WM831X_AUX_CAL;
 228
 229         if (src != input) {
 230                 dev_err(wm831x->dev, "Data from source %d not %d\n",
 231                         src, input);
 232                 ret = -EINVAL;
 233         } else {
 234                 ret &= WM831X_AUX_DATA_MASK;
 235         }
 236
 237 disable:
 238         wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL, WM831X_AUX_ENA, 0);
 239 out:
 240         mutex_unlock(&wm831x->auxadc_lock);
 241         return ret;
 242 }
 243
 244 /**
 245  * wm831x_auxadc_read: Read a value from the WM831x AUXADC
 246  *
 247  * @wm831x: Device to read from.
 248  * @input: AUXADC input to read.
 249  */
 250 int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input)
 251 {
 252         return wm831x->auxadc_read(wm831x, input);
 253 }
 254 EXPORT_SYMBOL_GPL(wm831x_auxadc_read);
 255
 256 /**
 257  * wm831x_auxadc_read_uv: Read a voltage from the WM831x AUXADC
 258  *
 259  * @wm831x: Device to read from.
 260  * @input: AUXADC input to read.
 261  */
 262 int wm831x_auxadc_read_uv(struct wm831x *wm831x, enum wm831x_auxadc input)
 263 {
 264         int ret;
 265
 266         ret = wm831x_auxadc_read(wm831x, input);
 267         if (ret < 0)
 268                 return ret;
 269
 270         ret *= 1465;
 271
 272         return ret;
 273 }
 274 EXPORT_SYMBOL_GPL(wm831x_auxadc_read_uv);
 275
 276 void wm831x_auxadc_init(struct wm831x *wm831x)
 277 {
 278         int ret;
 279
 280         mutex_init(&wm831x->auxadc_lock);
 281         INIT_LIST_HEAD(&wm831x->auxadc_pending);
 282
 283         if (wm831x->irq) {
 284                 wm831x->auxadc_read = wm831x_auxadc_read_irq;
 285
 286                 ret = request_threaded_irq(wm831x_irq(wm831x,
 287                                                       WM831X_IRQ_AUXADC_DATA),
 288                                            NULL, wm831x_auxadc_irq,
 289                                            IRQF_ONESHOT,
 290                                            "auxadc", wm831x);
 291                 if (ret < 0) {
 292                         dev_err(wm831x->dev, "AUXADC IRQ request failed: %d\n",
 293                                 ret);
 294                         wm831x->auxadc_read = NULL;
 295                 }
 296         }
 297
 298         if (!wm831x->auxadc_read)
 299                 wm831x->auxadc_read = wm831x_auxadc_read_polled;
 300 }