drivers/staging/greybus/pwm.c

   1 /*
   2  * PWM Greybus driver.
   3  *
   4  * Copyright 2014 Google Inc.
   5  * Copyright 2014 Linaro Ltd.
   6  *
   7  * Released under the GPLv2 only.
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/pwm.h>
  14
  15 #include "greybus.h"
  16 #include "gbphy.h"
  17
  18 struct gb_pwm_chip {
  19         struct gb_connection    *connection;
  20         u8                      pwm_max;        /* max pwm number */
  21
  22         struct pwm_chip         chip;
  23         struct pwm_chip         *pwm;
  24 };
  25 #define pwm_chip_to_gb_pwm_chip(chip) \
  26         container_of(chip, struct gb_pwm_chip, chip)
  27
  28
  29 static int gb_pwm_count_operation(struct gb_pwm_chip *pwmc)
  30 {
  31         struct gb_pwm_count_response response;
  32         int ret;
  33
  34         ret = gb_operation_sync(pwmc->connection, GB_PWM_TYPE_PWM_COUNT,
  35                                 NULL, 0, &response, sizeof(response));
  36         if (ret)
  37                 return ret;
  38         pwmc->pwm_max = response.count;
  39         return 0;
  40 }
  41
  42 static int gb_pwm_activate_operation(struct gb_pwm_chip *pwmc,
  43                                      u8 which)
  44 {
  45         struct gb_pwm_activate_request request;
  46
  47         if (which > pwmc->pwm_max)
  48                 return -EINVAL;
  49
  50         request.which = which;
  51         return gb_operation_sync(pwmc->connection, GB_PWM_TYPE_ACTIVATE,
  52                                  &request, sizeof(request), NULL, 0);
  53 }
  54
  55 static int gb_pwm_deactivate_operation(struct gb_pwm_chip *pwmc,
  56                                        u8 which)
  57 {
  58         struct gb_pwm_deactivate_request request;
  59
  60         if (which > pwmc->pwm_max)
  61                 return -EINVAL;
  62
  63         request.which = which;
  64         return gb_operation_sync(pwmc->connection, GB_PWM_TYPE_DEACTIVATE,
  65                                  &request, sizeof(request), NULL, 0);
  66 }
  67
  68 static int gb_pwm_config_operation(struct gb_pwm_chip *pwmc,
  69                                    u8 which, u32 duty, u32 period)
  70 {
  71         struct gb_pwm_config_request request;
  72
  73         if (which > pwmc->pwm_max)
  74                 return -EINVAL;
  75
  76         request.which = which;
  77         request.duty = cpu_to_le32(duty);
  78         request.period = cpu_to_le32(period);
  79         return gb_operation_sync(pwmc->connection, GB_PWM_TYPE_CONFIG,
  80                                  &request, sizeof(request), NULL, 0);
  81 }
  82
  83
  84 static int gb_pwm_set_polarity_operation(struct gb_pwm_chip *pwmc,
  85                                          u8 which, u8 polarity)
  86 {
  87         struct gb_pwm_polarity_request request;
  88
  89         if (which > pwmc->pwm_max)
  90                 return -EINVAL;
  91
  92         request.which = which;
  93         request.polarity = polarity;
  94         return gb_operation_sync(pwmc->connection, GB_PWM_TYPE_POLARITY,
  95                                  &request, sizeof(request), NULL, 0);
  96 }
  97
  98 static int gb_pwm_enable_operation(struct gb_pwm_chip *pwmc,
  99                                    u8 which)
 100 {
 101         struct gb_pwm_enable_request request;
 102
 103         if (which > pwmc->pwm_max)
 104                 return -EINVAL;
 105
 106         request.which = which;
 107         return gb_operation_sync(pwmc->connection, GB_PWM_TYPE_ENABLE,
 108                                  &request, sizeof(request), NULL, 0);
 109 }
 110
 111 static int gb_pwm_disable_operation(struct gb_pwm_chip *pwmc,
 112                                     u8 which)
 113 {
 114         struct gb_pwm_disable_request request;
 115
 116         if (which > pwmc->pwm_max)
 117                 return -EINVAL;
 118
 119         request.which = which;
 120         return gb_operation_sync(pwmc->connection, GB_PWM_TYPE_DISABLE,
 121                                  &request, sizeof(request), NULL, 0);
 122 }
 123
 124 static int gb_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 125 {
 126         struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
 127
 128         return gb_pwm_activate_operation(pwmc, pwm->hwpwm);
 129 };
 130
 131 static void gb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 132 {
 133         struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
 134
 135         if (test_bit(PWMF_ENABLED, &pwm->flags))
 136                 dev_warn(chip->dev, "freeing PWM device without disabling\n");
 137
 138         gb_pwm_deactivate_operation(pwmc, pwm->hwpwm);
 139 }
 140
 141 static int gb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 142                          int duty_ns, int period_ns)
 143 {
 144         struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
 145
 146         return gb_pwm_config_operation(pwmc, pwm->hwpwm, duty_ns, period_ns);
 147 };
 148
 149 static int gb_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
 150                                enum pwm_polarity polarity)
 151 {
 152         struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
 153
 154         return gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, polarity);
 155 };
 156
 157 static int gb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 158 {
 159         struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
 160
 161         return gb_pwm_enable_operation(pwmc, pwm->hwpwm);
 162 };
 163
 164 static void gb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 165 {
 166         struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
 167
 168         gb_pwm_disable_operation(pwmc, pwm->hwpwm);
 169 };
 170
 171 static const struct pwm_ops gb_pwm_ops = {
 172         .request = gb_pwm_request,
 173         .free = gb_pwm_free,
 174         .config = gb_pwm_config,
 175         .set_polarity = gb_pwm_set_polarity,
 176         .enable = gb_pwm_enable,
 177         .disable = gb_pwm_disable,
 178         .owner = THIS_MODULE,
 179 };
 180
 181 static int gb_pwm_probe(struct gbphy_device *gbphy_dev,
 182                         const struct gbphy_device_id *id)
 183 {
 184         struct gb_connection *connection;
 185         struct gb_pwm_chip *pwmc;
 186         struct pwm_chip *pwm;
 187         int ret;
 188
 189         pwmc = kzalloc(sizeof(*pwmc), GFP_KERNEL);
 190         if (!pwmc)
 191                 return -ENOMEM;
 192
 193         connection = gb_connection_create(gbphy_dev->bundle,
 194                                           le16_to_cpu(gbphy_dev->cport_desc->id),
 195                                           NULL);
 196         if (IS_ERR(connection)) {
 197                 ret = PTR_ERR(connection);
 198                 goto exit_pwmc_free;
 199         }
 200
 201         pwmc->connection = connection;
 202         gb_connection_set_data(connection, pwmc);
 203         gb_gbphy_set_data(gbphy_dev, pwmc);
 204
 205         ret = gb_connection_enable(connection);
 206         if (ret)
 207                 goto exit_connection_destroy;
 208
 209         ret = gb_gbphy_get_version(connection);
 210         if (ret)
 211                 goto exit_connection_disable;
 212
 213         /* Query number of pwms present */
 214         ret = gb_pwm_count_operation(pwmc);
 215         if (ret)
 216                 goto exit_connection_disable;
 217
 218         pwm = &pwmc->chip;
 219
 220         pwm->dev = &gbphy_dev->dev;
 221         pwm->ops = &gb_pwm_ops;
 222         pwm->base = -1;                 /* Allocate base dynamically */
 223         pwm->npwm = pwmc->pwm_max + 1;
 224         pwm->can_sleep = true;          /* FIXME */
 225
 226         ret = pwmchip_add(pwm);
 227         if (ret) {
 228                 dev_err(&gbphy_dev->dev,
 229                         "failed to register PWM: %d\n", ret);
 230                 goto exit_connection_disable;
 231         }
 232
 233         return 0;
 234
 235 exit_connection_disable:
 236         gb_connection_disable(connection);
 237 exit_connection_destroy:
 238         gb_connection_destroy(connection);
 239 exit_pwmc_free:
 240         kfree(pwmc);
 241         return ret;
 242 }
 243
 244 static void gb_pwm_remove(struct gbphy_device *gbphy_dev)
 245 {
 246         struct gb_pwm_chip *pwmc = gb_gbphy_get_data(gbphy_dev);
 247         struct gb_connection *connection = pwmc->connection;
 248
 249         pwmchip_remove(&pwmc->chip);
 250         gb_connection_disable(connection);
 251         gb_connection_destroy(connection);
 252         kfree(pwmc);
 253 }
 254
 255 static const struct gbphy_device_id gb_pwm_id_table[] = {
 256         { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_PWM) },
 257         { },
 258 };
 259 MODULE_DEVICE_TABLE(gbphy, gb_pwm_id_table);
 260
 261 static struct gbphy_driver pwm_driver = {
 262         .name           = "pwm",
 263         .probe          = gb_pwm_probe,
 264         .remove         = gb_pwm_remove,
 265         .id_table       = gb_pwm_id_table,
 266 };
 267
 268 module_gbphy_driver(pwm_driver);
 269 MODULE_LICENSE("GPL v2");