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;
 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 read the interrupt status register */
 183         msleep(20);
 184
 185         ret = wm831x_reg_read(wm831x, WM831X_INTERRUPT_STATUS_1);
 186         if (ret < 0) {
 187                 dev_err(wm831x->dev,
 188                         "ISR 1 read failed: %d\n", ret);
 189                 goto disable;
 190         }
 191
 192         /* Did it complete? */
 193         if (ret & WM831X_AUXADC_DATA_EINT) {
 194                 wm831x_reg_write(wm831x, WM831X_INTERRUPT_STATUS_1,
 195                                 WM831X_AUXADC_DATA_EINT);
 196         } else {
 197                 dev_err(wm831x->dev,
 198                         "AUXADC conversion timeout\n");
 199                 ret = -EBUSY;
 200                 goto disable;
 201         }
 202
 203         ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
 204         if (ret < 0) {
 205                 dev_err(wm831x->dev,
 206                         "Failed to read AUXADC data: %d\n", ret);
 207                 goto disable;
 208         }
 209
 210         src = ((ret & WM831X_AUX_DATA_SRC_MASK)
 211                >> WM831X_AUX_DATA_SRC_SHIFT) - 1;
 212
 213         if (src == 14)
 214                 src = WM831X_AUX_CAL;
 215
 216         if (src != input) {
 217                 dev_err(wm831x->dev, "Data from source %d not %d\n",
 218                         src, input);
 219                 ret = -EINVAL;
 220         } else {
 221                 ret &= WM831X_AUX_DATA_MASK;
 222         }
 223
 224 disable:
 225         wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL, WM831X_AUX_ENA, 0);
 226 out:
 227         mutex_unlock(&wm831x->auxadc_lock);
 228         return ret;
 229 }
 230
 231 /**
 232  * wm831x_auxadc_read: Read a value from the WM831x AUXADC
 233  *
 234  * @wm831x: Device to read from.
 235  * @input: AUXADC input to read.
 236  */
 237 int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input)
 238 {
 239         return wm831x->auxadc_read(wm831x, input);
 240 }
 241 EXPORT_SYMBOL_GPL(wm831x_auxadc_read);
 242
 243 /**
 244  * wm831x_auxadc_read_uv: Read a voltage from the WM831x AUXADC
 245  *
 246  * @wm831x: Device to read from.
 247  * @input: AUXADC input to read.
 248  */
 249 int wm831x_auxadc_read_uv(struct wm831x *wm831x, enum wm831x_auxadc input)
 250 {
 251         int ret;
 252
 253         ret = wm831x_auxadc_read(wm831x, input);
 254         if (ret < 0)
 255                 return ret;
 256
 257         ret *= 1465;
 258
 259         return ret;
 260 }
 261 EXPORT_SYMBOL_GPL(wm831x_auxadc_read_uv);
 262
 263 void wm831x_auxadc_init(struct wm831x *wm831x)
 264 {
 265         int ret;
 266
 267         mutex_init(&wm831x->auxadc_lock);
 268         INIT_LIST_HEAD(&wm831x->auxadc_pending);
 269
 270         if (wm831x->irq) {
 271                 wm831x->auxadc_read = wm831x_auxadc_read_irq;
 272
 273                 ret = request_threaded_irq(wm831x_irq(wm831x,
 274                                                       WM831X_IRQ_AUXADC_DATA),
 275                                            NULL, wm831x_auxadc_irq,
 276                                            IRQF_ONESHOT,
 277                                            "auxadc", wm831x);
 278                 if (ret < 0) {
 279                         dev_err(wm831x->dev, "AUXADC IRQ request failed: %d\n",
 280                                 ret);
 281                         wm831x->auxadc_read = NULL;
 282                 }
 283         }
 284
 285         if (!wm831x->auxadc_read)
 286                 wm831x->auxadc_read = wm831x_auxadc_read_polled;
 287 }