drivers/mfd/wm831x-auxadc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * wm831x-auxadc.c  --  AUXADC for Wolfson WM831x PMICs
   4  *
   5  * Copyright 2009-2011 Wolfson Microelectronics PLC.
   6  *
   7  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/delay.h>
  13 #include <linux/mfd/core.h>
  14 #include <linux/slab.h>
  15 #include <linux/list.h>
  16
  17 #include <linux/mfd/wm831x/core.h>
  18 #include <linux/mfd/wm831x/pdata.h>
  19 #include <linux/mfd/wm831x/irq.h>
  20 #include <linux/mfd/wm831x/auxadc.h>
  21 #include <linux/mfd/wm831x/otp.h>
  22 #include <linux/mfd/wm831x/regulator.h>
  23
  24 struct wm831x_auxadc_req {
  25         struct list_head list;
  26         enum wm831x_auxadc input;
  27         int val;
  28         struct completion done;
  29 };
  30
  31 static int wm831x_auxadc_read_irq(struct wm831x *wm831x,
  32                                   enum wm831x_auxadc input)
  33 {
  34         struct wm831x_auxadc_req *req;
  35         int ret;
  36         bool ena = false;
  37
  38         req = kzalloc(sizeof(*req), GFP_KERNEL);
  39         if (!req)
  40                 return -ENOMEM;
  41
  42         init_completion(&req->done);
  43         req->input = input;
  44         req->val = -ETIMEDOUT;
  45
  46         mutex_lock(&wm831x->auxadc_lock);
  47
  48         /* Enqueue the request */
  49         list_add(&req->list, &wm831x->auxadc_pending);
  50
  51         ena = !wm831x->auxadc_active;
  52
  53         if (ena) {
  54                 ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
  55                                       WM831X_AUX_ENA, WM831X_AUX_ENA);
  56                 if (ret != 0) {
  57                         dev_err(wm831x->dev, "Failed to enable AUXADC: %d\n",
  58                                 ret);
  59                         goto out;
  60                 }
  61         }
  62
  63         /* Enable the conversion if not already running */
  64         if (!(wm831x->auxadc_active & (1 << input))) {
  65                 ret = wm831x_set_bits(wm831x, WM831X_AUXADC_SOURCE,
  66                                       1 << input, 1 << input);
  67                 if (ret != 0) {
  68                         dev_err(wm831x->dev,
  69                                 "Failed to set AUXADC source: %d\n", ret);
  70                         goto out;
  71                 }
  72
  73                 wm831x->auxadc_active |= 1 << input;
  74         }
  75
  76         /* We convert at the fastest rate possible */
  77         if (ena) {
  78                 ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
  79                                       WM831X_AUX_CVT_ENA |
  80                                       WM831X_AUX_RATE_MASK,
  81                                       WM831X_AUX_CVT_ENA |
  82                                       WM831X_AUX_RATE_MASK);
  83                 if (ret != 0) {
  84                         dev_err(wm831x->dev, "Failed to start AUXADC: %d\n",
  85                                 ret);
  86                         goto out;
  87                 }
  88         }
  89
  90         mutex_unlock(&wm831x->auxadc_lock);
  91
  92         /* Wait for an interrupt */
  93         wait_for_completion_timeout(&req->done, msecs_to_jiffies(500));
  94
  95         mutex_lock(&wm831x->auxadc_lock);
  96         ret = req->val;
  97
  98 out:
  99         list_del(&req->list);
 100         mutex_unlock(&wm831x->auxadc_lock);
 101
 102         kfree(req);
 103
 104         return ret;
 105 }
 106
 107 static irqreturn_t wm831x_auxadc_irq(int irq, void *irq_data)
 108 {
 109         struct wm831x *wm831x = irq_data;
 110         struct wm831x_auxadc_req *req;
 111         int ret, input, val;
 112
 113         ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
 114         if (ret < 0) {
 115                 dev_err(wm831x->dev,
 116                         "Failed to read AUXADC data: %d\n", ret);
 117                 return IRQ_NONE;
 118         }
 119
 120         input = ((ret & WM831X_AUX_DATA_SRC_MASK)
 121                  >> WM831X_AUX_DATA_SRC_SHIFT) - 1;
 122
 123         if (input == 14)
 124                 input = WM831X_AUX_CAL;
 125
 126         val = ret & WM831X_AUX_DATA_MASK;
 127
 128         mutex_lock(&wm831x->auxadc_lock);
 129
 130         /* Disable this conversion, we're about to complete all users */
 131         wm831x_set_bits(wm831x, WM831X_AUXADC_SOURCE,
 132                         1 << input, 0);
 133         wm831x->auxadc_active &= ~(1 << input);
 134
 135         /* Turn off the entire convertor if idle */
 136         if (!wm831x->auxadc_active)
 137                 wm831x_reg_write(wm831x, WM831X_AUXADC_CONTROL, 0);
 138
 139         /* Wake up any threads waiting for this request */
 140         list_for_each_entry(req, &wm831x->auxadc_pending, list) {
 141                 if (req->input == input) {
 142                         req->val = val;
 143                         complete(&req->done);
 144                 }
 145         }
 146
 147         mutex_unlock(&wm831x->auxadc_lock);
 148
 149         return IRQ_HANDLED;
 150 }
 151
 152 static int wm831x_auxadc_read_polled(struct wm831x *wm831x,
 153                                      enum wm831x_auxadc input)
 154 {
 155         int ret, src, timeout;
 156
 157         mutex_lock(&wm831x->auxadc_lock);
 158
 159         ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
 160                               WM831X_AUX_ENA, WM831X_AUX_ENA);
 161         if (ret < 0) {
 162                 dev_err(wm831x->dev, "Failed to enable AUXADC: %d\n", ret);
 163                 goto out;
 164         }
 165
 166         /* We force a single source at present */
 167         src = input;
 168         ret = wm831x_reg_write(wm831x, WM831X_AUXADC_SOURCE,
 169                                1 << src);
 170         if (ret < 0) {
 171                 dev_err(wm831x->dev, "Failed to set AUXADC source: %d\n", ret);
 172                 goto out;
 173         }
 174
 175         ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
 176                               WM831X_AUX_CVT_ENA, WM831X_AUX_CVT_ENA);
 177         if (ret < 0) {
 178                 dev_err(wm831x->dev, "Failed to start AUXADC: %d\n", ret);
 179                 goto disable;
 180         }
 181
 182         /* If we're not using interrupts then poll the
 183          * interrupt status register */
 184         timeout = 5;
 185         while (timeout) {
 186                 msleep(1);
 187
 188                 ret = wm831x_reg_read(wm831x,
 189                                       WM831X_INTERRUPT_STATUS_1);
 190                 if (ret < 0) {
 191                         dev_err(wm831x->dev,
 192                                 "ISR 1 read failed: %d\n", ret);
 193                         goto disable;
 194                 }
 195
 196                 /* Did it complete? */
 197                 if (ret & WM831X_AUXADC_DATA_EINT) {
 198                         wm831x_reg_write(wm831x,
 199                                          WM831X_INTERRUPT_STATUS_1,
 200                                          WM831X_AUXADC_DATA_EINT);
 201                         break;
 202                 } else {
 203                         dev_err(wm831x->dev,
 204                                 "AUXADC conversion timeout\n");
 205                         ret = -EBUSY;
 206                         goto disable;
 207                 }
 208         }
 209
 210         ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
 211         if (ret < 0) {
 212                 dev_err(wm831x->dev,
 213                         "Failed to read AUXADC data: %d\n", ret);
 214                 goto disable;
 215         }
 216
 217         src = ((ret & WM831X_AUX_DATA_SRC_MASK)
 218                >> WM831X_AUX_DATA_SRC_SHIFT) - 1;
 219
 220         if (src == 14)
 221                 src = WM831X_AUX_CAL;
 222
 223         if (src != input) {
 224                 dev_err(wm831x->dev, "Data from source %d not %d\n",
 225                         src, input);
 226                 ret = -EINVAL;
 227         } else {
 228                 ret &= WM831X_AUX_DATA_MASK;
 229         }
 230
 231 disable:
 232         wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL, WM831X_AUX_ENA, 0);
 233 out:
 234         mutex_unlock(&wm831x->auxadc_lock);
 235         return ret;
 236 }
 237
 238 /**
 239  * wm831x_auxadc_read: Read a value from the WM831x AUXADC
 240  *
 241  * @wm831x: Device to read from.
 242  * @input: AUXADC input to read.
 243  */
 244 int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input)
 245 {
 246         return wm831x->auxadc_read(wm831x, input);
 247 }
 248 EXPORT_SYMBOL_GPL(wm831x_auxadc_read);
 249
 250 /**
 251  * wm831x_auxadc_read_uv: Read a voltage from the WM831x AUXADC
 252  *
 253  * @wm831x: Device to read from.
 254  * @input: AUXADC input to read.
 255  */
 256 int wm831x_auxadc_read_uv(struct wm831x *wm831x, enum wm831x_auxadc input)
 257 {
 258         int ret;
 259
 260         ret = wm831x_auxadc_read(wm831x, input);
 261         if (ret < 0)
 262                 return ret;
 263
 264         ret *= 1465;
 265
 266         return ret;
 267 }
 268 EXPORT_SYMBOL_GPL(wm831x_auxadc_read_uv);
 269
 270 void wm831x_auxadc_init(struct wm831x *wm831x)
 271 {
 272         int ret;
 273
 274         mutex_init(&wm831x->auxadc_lock);
 275         INIT_LIST_HEAD(&wm831x->auxadc_pending);
 276
 277         if (wm831x->irq) {
 278                 wm831x->auxadc_read = wm831x_auxadc_read_irq;
 279
 280                 ret = request_threaded_irq(wm831x_irq(wm831x,
 281                                                       WM831X_IRQ_AUXADC_DATA),
 282                                            NULL, wm831x_auxadc_irq,
 283                                            IRQF_ONESHOT,
 284                                            "auxadc", wm831x);
 285                 if (ret < 0) {
 286                         dev_err(wm831x->dev, "AUXADC IRQ request failed: %d\n",
 287                                 ret);
 288                         wm831x->auxadc_read = NULL;
 289                 }
 290         }
 291
 292         if (!wm831x->auxadc_read)
 293                 wm831x->auxadc_read = wm831x_auxadc_read_polled;
 294 }