Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 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 | #include "greybus.h" |
| 15 | |
| 16 | struct gb_pwm_chip { |
| 17 | struct gb_connection *connection; |
| 18 | u8 version_major; |
| 19 | u8 version_minor; |
| 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 | /* Version of the Greybus PWM protocol we support */ |
| 29 | #define GB_PWM_VERSION_MAJOR 0x00 |
| 30 | #define GB_PWM_VERSION_MINOR 0x01 |
| 31 | |
| 32 | /* Greybus PWM request types */ |
| 33 | #define GB_PWM_TYPE_INVALID 0x00 |
| 34 | #define GB_PWM_TYPE_PROTOCOL_VERSION 0x01 |
| 35 | #define GB_PWM_TYPE_PWM_COUNT 0x02 |
| 36 | #define GB_PWM_TYPE_ACTIVATE 0x03 |
| 37 | #define GB_PWM_TYPE_DEACTIVATE 0x04 |
| 38 | #define GB_PWM_TYPE_CONFIG 0x05 |
| 39 | #define GB_PWM_TYPE_POLARITY 0x06 |
| 40 | #define GB_PWM_TYPE_ENABLE 0x07 |
| 41 | #define GB_PWM_TYPE_DISABLE 0x08 |
| 42 | #define GB_PWM_TYPE_RESPONSE 0x80 /* OR'd with rest */ |
| 43 | |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 44 | /* version request has no payload */ |
| 45 | struct gb_pwm_proto_version_response { |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 46 | __u8 major; |
| 47 | __u8 minor; |
| 48 | }; |
| 49 | |
| 50 | /* pwm count request has no payload */ |
| 51 | struct gb_pwm_count_response { |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 52 | __u8 count; |
| 53 | }; |
| 54 | |
| 55 | struct gb_pwm_activate_request { |
| 56 | __u8 which; |
| 57 | }; |
| 58 | |
| 59 | struct gb_pwm_deactivate_request { |
| 60 | __u8 which; |
| 61 | }; |
| 62 | |
| 63 | struct gb_pwm_config_request { |
| 64 | __u8 which; |
Alex Elder | 583d233 | 2014-12-02 15:48:09 -0600 | [diff] [blame] | 65 | __le32 duty; |
| 66 | __le32 period; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 67 | }; |
| 68 | |
| 69 | struct gb_pwm_polarity_request { |
| 70 | __u8 which; |
| 71 | __u8 polarity; |
| 72 | }; |
| 73 | |
| 74 | struct gb_pwm_enable_request { |
| 75 | __u8 which; |
| 76 | }; |
| 77 | |
| 78 | struct gb_pwm_disable_request { |
| 79 | __u8 which; |
| 80 | }; |
| 81 | |
| 82 | /* |
| 83 | * This request only uses the connection field, and if successful, |
| 84 | * fills in the major and minor protocol version of the target. |
| 85 | */ |
| 86 | static int gb_pwm_proto_version_operation(struct gb_pwm_chip *pwmc) |
| 87 | { |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 88 | struct gb_pwm_proto_version_response response; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 89 | int ret; |
| 90 | |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 91 | ret = gb_operation_sync(pwmc->connection, GB_PWM_TYPE_PROTOCOL_VERSION, |
| 92 | NULL, 0, &response, sizeof(response)); |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 93 | |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 94 | if (ret) |
| 95 | return ret; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 96 | |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 97 | if (response.major > GB_PWM_VERSION_MAJOR) { |
Alex Elder | 23383de | 2014-11-21 19:29:12 -0600 | [diff] [blame] | 98 | pr_err("unsupported major version (%hhu > %hhu)\n", |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 99 | response.major, GB_PWM_VERSION_MAJOR); |
| 100 | return -ENOTSUPP; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 101 | } |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 102 | pwmc->version_major = response.major; |
| 103 | pwmc->version_minor = response.minor; |
| 104 | return 0; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 105 | } |
| 106 | |
| 107 | static int gb_pwm_count_operation(struct gb_pwm_chip *pwmc) |
| 108 | { |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 109 | struct gb_pwm_count_response response; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 110 | int ret; |
| 111 | |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 112 | ret = gb_operation_sync(pwmc->connection, GB_PWM_TYPE_PWM_COUNT, |
| 113 | NULL, 0, &response, sizeof(response)); |
| 114 | if (ret) |
| 115 | return ret; |
| 116 | pwmc->pwm_max = response.count; |
| 117 | return 0; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 118 | } |
| 119 | |
| 120 | static int gb_pwm_activate_operation(struct gb_pwm_chip *pwmc, |
| 121 | u8 which) |
| 122 | { |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 123 | struct gb_pwm_activate_request request; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 124 | |
| 125 | if (which > pwmc->pwm_max) |
| 126 | return -EINVAL; |
| 127 | |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 128 | request.which = which; |
| 129 | return gb_operation_sync(pwmc->connection, GB_PWM_TYPE_ACTIVATE, |
| 130 | &request, sizeof(request), NULL, 0); |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 131 | } |
| 132 | |
| 133 | static int gb_pwm_deactivate_operation(struct gb_pwm_chip *pwmc, |
| 134 | u8 which) |
| 135 | { |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 136 | struct gb_pwm_deactivate_request request; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 137 | |
| 138 | if (which > pwmc->pwm_max) |
| 139 | return -EINVAL; |
| 140 | |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 141 | request.which = which; |
| 142 | return gb_operation_sync(pwmc->connection, GB_PWM_TYPE_DEACTIVATE, |
| 143 | &request, sizeof(request), NULL, 0); |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 144 | } |
| 145 | |
| 146 | static int gb_pwm_config_operation(struct gb_pwm_chip *pwmc, |
| 147 | u8 which, u32 duty, u32 period) |
| 148 | { |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 149 | struct gb_pwm_config_request request; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 150 | |
| 151 | if (which > pwmc->pwm_max) |
| 152 | return -EINVAL; |
| 153 | |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 154 | request.which = which; |
Alex Elder | 583d233 | 2014-12-02 15:48:09 -0600 | [diff] [blame] | 155 | request.duty = cpu_to_le32(duty); |
| 156 | request.period = cpu_to_le32(period); |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 157 | return gb_operation_sync(pwmc->connection, GB_PWM_TYPE_CONFIG, |
| 158 | &request, sizeof(request), NULL, 0); |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 159 | } |
| 160 | |
| 161 | |
| 162 | static int gb_pwm_set_polarity_operation(struct gb_pwm_chip *pwmc, |
| 163 | u8 which, u8 polarity) |
| 164 | { |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 165 | struct gb_pwm_polarity_request request; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 166 | |
| 167 | if (which > pwmc->pwm_max) |
| 168 | return -EINVAL; |
| 169 | |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 170 | request.which = which; |
| 171 | request.polarity = polarity; |
| 172 | return gb_operation_sync(pwmc->connection, GB_PWM_TYPE_POLARITY, |
| 173 | &request, sizeof(request), NULL, 0); |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 174 | } |
| 175 | |
| 176 | static int gb_pwm_enable_operation(struct gb_pwm_chip *pwmc, |
| 177 | u8 which) |
| 178 | { |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 179 | struct gb_pwm_enable_request request; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 180 | |
| 181 | if (which > pwmc->pwm_max) |
| 182 | return -EINVAL; |
| 183 | |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 184 | request.which = which; |
| 185 | return gb_operation_sync(pwmc->connection, GB_PWM_TYPE_ENABLE, |
| 186 | &request, sizeof(request), NULL, 0); |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 187 | } |
| 188 | |
| 189 | static int gb_pwm_disable_operation(struct gb_pwm_chip *pwmc, |
| 190 | u8 which) |
| 191 | { |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 192 | struct gb_pwm_disable_request request; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 193 | |
| 194 | if (which > pwmc->pwm_max) |
| 195 | return -EINVAL; |
| 196 | |
Greg Kroah-Hartman | bf2329f | 2014-11-23 17:45:24 -0800 | [diff] [blame] | 197 | request.which = which; |
| 198 | return gb_operation_sync(pwmc->connection, GB_PWM_TYPE_DISABLE, |
| 199 | &request, sizeof(request), NULL, 0); |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 200 | } |
| 201 | |
| 202 | static int gb_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) |
| 203 | { |
| 204 | struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip); |
| 205 | |
| 206 | return gb_pwm_activate_operation(pwmc, pwm->hwpwm); |
| 207 | }; |
| 208 | |
| 209 | static void gb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) |
| 210 | { |
| 211 | struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip); |
| 212 | |
| 213 | if (test_bit(PWMF_ENABLED, &pwm->flags)) |
| 214 | dev_warn(chip->dev, "freeing PWM device without disabling\n"); |
| 215 | |
| 216 | gb_pwm_deactivate_operation(pwmc, pwm->hwpwm); |
| 217 | } |
| 218 | |
| 219 | static int gb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, |
| 220 | int duty_ns, int period_ns) |
| 221 | { |
| 222 | struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip); |
| 223 | |
| 224 | return gb_pwm_config_operation(pwmc, pwm->hwpwm, duty_ns, period_ns); |
| 225 | }; |
| 226 | |
| 227 | static int gb_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, |
| 228 | enum pwm_polarity polarity) |
| 229 | { |
| 230 | struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip); |
| 231 | |
| 232 | return gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, polarity); |
| 233 | }; |
| 234 | |
| 235 | static int gb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 236 | { |
| 237 | struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip); |
| 238 | |
| 239 | return gb_pwm_enable_operation(pwmc, pwm->hwpwm); |
| 240 | }; |
| 241 | |
| 242 | static void gb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 243 | { |
| 244 | struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip); |
| 245 | |
| 246 | gb_pwm_disable_operation(pwmc, pwm->hwpwm); |
| 247 | }; |
| 248 | |
| 249 | static const struct pwm_ops gb_pwm_ops = { |
| 250 | .request = gb_pwm_request, |
| 251 | .free = gb_pwm_free, |
| 252 | .config = gb_pwm_config, |
| 253 | .set_polarity = gb_pwm_set_polarity, |
| 254 | .enable = gb_pwm_enable, |
| 255 | .disable = gb_pwm_disable, |
| 256 | .owner = THIS_MODULE, |
| 257 | }; |
| 258 | |
| 259 | static int gb_pwm_connection_init(struct gb_connection *connection) |
| 260 | { |
| 261 | struct gb_pwm_chip *pwmc; |
| 262 | struct pwm_chip *pwm; |
| 263 | int ret; |
| 264 | |
| 265 | pwmc = kzalloc(sizeof(*pwmc), GFP_KERNEL); |
| 266 | if (!pwmc) |
| 267 | return -ENOMEM; |
| 268 | pwmc->connection = connection; |
Alex Elder | 93bbe85 | 2014-12-03 12:27:42 -0600 | [diff] [blame^] | 269 | connection->private = pwmc; |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 270 | |
| 271 | /* Check for compatible protocol version */ |
| 272 | ret = gb_pwm_proto_version_operation(pwmc); |
| 273 | if (ret) |
| 274 | goto out_err; |
| 275 | |
| 276 | /* Query number of pwms present */ |
| 277 | ret = gb_pwm_count_operation(pwmc); |
| 278 | if (ret) |
| 279 | goto out_err; |
| 280 | |
| 281 | pwm = &pwmc->chip; |
| 282 | |
| 283 | pwm->dev = &connection->dev; |
| 284 | pwm->ops = &gb_pwm_ops; |
| 285 | pwm->base = -1; /* Allocate base dynamically */ |
| 286 | pwm->npwm = pwmc->pwm_max + 1; |
| 287 | pwm->can_sleep = true; /* FIXME */ |
| 288 | |
| 289 | ret = pwmchip_add(pwm); |
| 290 | if (ret) { |
| 291 | pr_err("Failed to register PWM\n"); |
| 292 | return ret; |
| 293 | } |
Matt Porter | 34c6507 | 2014-11-13 09:14:13 -0500 | [diff] [blame] | 294 | |
| 295 | return 0; |
| 296 | out_err: |
| 297 | kfree(pwmc); |
| 298 | return ret; |
| 299 | } |
| 300 | |
| 301 | static void gb_pwm_connection_exit(struct gb_connection *connection) |
| 302 | { |
| 303 | struct gb_pwm_chip *pwmc = connection->private; |
| 304 | |
| 305 | if (!pwmc) |
| 306 | return; |
| 307 | |
| 308 | pwmchip_remove(&pwmc->chip); |
| 309 | /* kref_put(pwmc->connection) */ |
| 310 | kfree(pwmc); |
| 311 | } |
| 312 | |
| 313 | static struct gb_protocol pwm_protocol = { |
| 314 | .id = GREYBUS_PROTOCOL_PWM, |
| 315 | .major = 0, |
| 316 | .minor = 1, |
| 317 | .connection_init = gb_pwm_connection_init, |
| 318 | .connection_exit = gb_pwm_connection_exit, |
| 319 | .request_recv = NULL, /* no incoming requests */ |
| 320 | }; |
| 321 | |
| 322 | bool gb_pwm_protocol_init(void) |
| 323 | { |
| 324 | return gb_protocol_register(&pwm_protocol); |
| 325 | } |
| 326 | |
| 327 | void gb_pwm_protocol_exit(void) |
| 328 | { |
| 329 | gb_protocol_deregister(&pwm_protocol); |
| 330 | } |