Paul Burton | 0cad855 | 2016-08-26 15:17:49 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2016 Imagination Technologies |
| 3 | * Author: Paul Burton <paul.burton@imgtec.com> |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License as published by the |
| 7 | * Free Software Foundation; either version 2 of the License, or (at your |
| 8 | * option) any later version. |
| 9 | */ |
| 10 | |
| 11 | #include <generated/utsrelease.h> |
| 12 | #include <linux/kernel.h> |
| 13 | #include <linux/io.h> |
| 14 | #include <linux/mfd/syscon.h> |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/of_address.h> |
| 17 | #include <linux/of_platform.h> |
| 18 | #include <linux/platform_device.h> |
| 19 | #include <linux/regmap.h> |
| 20 | #include <linux/slab.h> |
| 21 | #include <linux/sysfs.h> |
| 22 | |
| 23 | struct img_ascii_lcd_ctx; |
| 24 | |
| 25 | /** |
| 26 | * struct img_ascii_lcd_config - Configuration information about an LCD model |
| 27 | * @num_chars: the number of characters the LCD can display |
| 28 | * @external_regmap: true if registers are in a system controller, else false |
| 29 | * @update: function called to update the LCD |
| 30 | */ |
| 31 | struct img_ascii_lcd_config { |
| 32 | unsigned int num_chars; |
| 33 | bool external_regmap; |
| 34 | void (*update)(struct img_ascii_lcd_ctx *ctx); |
| 35 | }; |
| 36 | |
| 37 | /** |
| 38 | * struct img_ascii_lcd_ctx - Private data structure |
| 39 | * @pdev: the ASCII LCD platform device |
| 40 | * @base: the base address of the LCD registers |
| 41 | * @regmap: the regmap through which LCD registers are accessed |
| 42 | * @offset: the offset within regmap to the start of the LCD registers |
| 43 | * @cfg: pointer to the LCD model configuration |
| 44 | * @message: the full message to display or scroll on the LCD |
| 45 | * @message_len: the length of the @message string |
| 46 | * @scroll_pos: index of the first character of @message currently displayed |
| 47 | * @scroll_rate: scroll interval in jiffies |
| 48 | * @timer: timer used to implement scrolling |
| 49 | * @curr: the string currently displayed on the LCD |
| 50 | */ |
| 51 | struct img_ascii_lcd_ctx { |
| 52 | struct platform_device *pdev; |
| 53 | union { |
| 54 | void __iomem *base; |
| 55 | struct regmap *regmap; |
| 56 | }; |
| 57 | u32 offset; |
| 58 | const struct img_ascii_lcd_config *cfg; |
| 59 | char *message; |
| 60 | unsigned int message_len; |
| 61 | unsigned int scroll_pos; |
| 62 | unsigned int scroll_rate; |
| 63 | struct timer_list timer; |
| 64 | char curr[] __aligned(8); |
| 65 | }; |
| 66 | |
| 67 | /* |
| 68 | * MIPS Boston development board |
| 69 | */ |
| 70 | |
| 71 | static void boston_update(struct img_ascii_lcd_ctx *ctx) |
| 72 | { |
| 73 | ulong val; |
| 74 | |
| 75 | #if BITS_PER_LONG == 64 |
| 76 | val = *((u64 *)&ctx->curr[0]); |
| 77 | __raw_writeq(val, ctx->base); |
| 78 | #elif BITS_PER_LONG == 32 |
| 79 | val = *((u32 *)&ctx->curr[0]); |
| 80 | __raw_writel(val, ctx->base); |
| 81 | val = *((u32 *)&ctx->curr[4]); |
| 82 | __raw_writel(val, ctx->base + 4); |
| 83 | #else |
| 84 | # error Not 32 or 64 bit |
| 85 | #endif |
| 86 | } |
| 87 | |
| 88 | static struct img_ascii_lcd_config boston_config = { |
| 89 | .num_chars = 8, |
| 90 | .update = boston_update, |
| 91 | }; |
| 92 | |
| 93 | /* |
| 94 | * MIPS Malta development board |
| 95 | */ |
| 96 | |
| 97 | static void malta_update(struct img_ascii_lcd_ctx *ctx) |
| 98 | { |
| 99 | unsigned int i; |
| 100 | int err; |
| 101 | |
| 102 | for (i = 0; i < ctx->cfg->num_chars; i++) { |
| 103 | err = regmap_write(ctx->regmap, |
| 104 | ctx->offset + (i * 8), ctx->curr[i]); |
| 105 | if (err) |
| 106 | break; |
| 107 | } |
| 108 | |
| 109 | if (unlikely(err)) |
| 110 | pr_err_ratelimited("Failed to update LCD display: %d\n", err); |
| 111 | } |
| 112 | |
| 113 | static struct img_ascii_lcd_config malta_config = { |
| 114 | .num_chars = 8, |
| 115 | .external_regmap = true, |
| 116 | .update = malta_update, |
| 117 | }; |
| 118 | |
| 119 | /* |
| 120 | * MIPS SEAD3 development board |
| 121 | */ |
| 122 | |
| 123 | enum { |
| 124 | SEAD3_REG_LCD_CTRL = 0x00, |
| 125 | #define SEAD3_REG_LCD_CTRL_SETDRAM BIT(7) |
| 126 | SEAD3_REG_LCD_DATA = 0x08, |
| 127 | SEAD3_REG_CPLD_STATUS = 0x10, |
| 128 | #define SEAD3_REG_CPLD_STATUS_BUSY BIT(0) |
| 129 | SEAD3_REG_CPLD_DATA = 0x18, |
| 130 | #define SEAD3_REG_CPLD_DATA_BUSY BIT(7) |
| 131 | }; |
| 132 | |
| 133 | static int sead3_wait_sm_idle(struct img_ascii_lcd_ctx *ctx) |
| 134 | { |
| 135 | unsigned int status; |
| 136 | int err; |
| 137 | |
| 138 | do { |
| 139 | err = regmap_read(ctx->regmap, |
| 140 | ctx->offset + SEAD3_REG_CPLD_STATUS, |
| 141 | &status); |
| 142 | if (err) |
| 143 | return err; |
| 144 | } while (status & SEAD3_REG_CPLD_STATUS_BUSY); |
| 145 | |
| 146 | return 0; |
| 147 | |
| 148 | } |
| 149 | |
| 150 | static int sead3_wait_lcd_idle(struct img_ascii_lcd_ctx *ctx) |
| 151 | { |
| 152 | unsigned int cpld_data; |
| 153 | int err; |
| 154 | |
| 155 | err = sead3_wait_sm_idle(ctx); |
| 156 | if (err) |
| 157 | return err; |
| 158 | |
| 159 | do { |
| 160 | err = regmap_read(ctx->regmap, |
| 161 | ctx->offset + SEAD3_REG_LCD_CTRL, |
| 162 | &cpld_data); |
| 163 | if (err) |
| 164 | return err; |
| 165 | |
| 166 | err = sead3_wait_sm_idle(ctx); |
| 167 | if (err) |
| 168 | return err; |
| 169 | |
| 170 | err = regmap_read(ctx->regmap, |
| 171 | ctx->offset + SEAD3_REG_CPLD_DATA, |
| 172 | &cpld_data); |
| 173 | if (err) |
| 174 | return err; |
| 175 | } while (cpld_data & SEAD3_REG_CPLD_DATA_BUSY); |
| 176 | |
| 177 | return 0; |
| 178 | } |
| 179 | |
| 180 | static void sead3_update(struct img_ascii_lcd_ctx *ctx) |
| 181 | { |
| 182 | unsigned int i; |
| 183 | int err; |
| 184 | |
| 185 | for (i = 0; i < ctx->cfg->num_chars; i++) { |
| 186 | err = sead3_wait_lcd_idle(ctx); |
| 187 | if (err) |
| 188 | break; |
| 189 | |
| 190 | err = regmap_write(ctx->regmap, |
| 191 | ctx->offset + SEAD3_REG_LCD_CTRL, |
| 192 | SEAD3_REG_LCD_CTRL_SETDRAM | i); |
| 193 | if (err) |
| 194 | break; |
| 195 | |
| 196 | err = sead3_wait_lcd_idle(ctx); |
| 197 | if (err) |
| 198 | break; |
| 199 | |
| 200 | err = regmap_write(ctx->regmap, |
| 201 | ctx->offset + SEAD3_REG_LCD_DATA, |
| 202 | ctx->curr[i]); |
| 203 | if (err) |
| 204 | break; |
| 205 | } |
| 206 | |
| 207 | if (unlikely(err)) |
| 208 | pr_err_ratelimited("Failed to update LCD display: %d\n", err); |
| 209 | } |
| 210 | |
| 211 | static struct img_ascii_lcd_config sead3_config = { |
| 212 | .num_chars = 16, |
| 213 | .external_regmap = true, |
| 214 | .update = sead3_update, |
| 215 | }; |
| 216 | |
| 217 | static const struct of_device_id img_ascii_lcd_matches[] = { |
| 218 | { .compatible = "img,boston-lcd", .data = &boston_config }, |
| 219 | { .compatible = "mti,malta-lcd", .data = &malta_config }, |
| 220 | { .compatible = "mti,sead3-lcd", .data = &sead3_config }, |
Dmitry Torokhov | 90f39ad | 2017-02-19 16:33:35 -0800 | [diff] [blame] | 221 | { /* sentinel */ } |
Paul Burton | 0cad855 | 2016-08-26 15:17:49 +0100 | [diff] [blame] | 222 | }; |
| 223 | |
| 224 | /** |
| 225 | * img_ascii_lcd_scroll() - scroll the display by a character |
| 226 | * @arg: really a pointer to the private data structure |
| 227 | * |
| 228 | * Scroll the current message along the LCD by one character, rearming the |
| 229 | * timer if required. |
| 230 | */ |
| 231 | static void img_ascii_lcd_scroll(unsigned long arg) |
| 232 | { |
| 233 | struct img_ascii_lcd_ctx *ctx = (struct img_ascii_lcd_ctx *)arg; |
| 234 | unsigned int i, ch = ctx->scroll_pos; |
| 235 | unsigned int num_chars = ctx->cfg->num_chars; |
| 236 | |
| 237 | /* update the current message string */ |
| 238 | for (i = 0; i < num_chars;) { |
| 239 | /* copy as many characters from the string as possible */ |
| 240 | for (; i < num_chars && ch < ctx->message_len; i++, ch++) |
| 241 | ctx->curr[i] = ctx->message[ch]; |
| 242 | |
| 243 | /* wrap around to the start of the string */ |
| 244 | ch = 0; |
| 245 | } |
| 246 | |
| 247 | /* update the LCD */ |
| 248 | ctx->cfg->update(ctx); |
| 249 | |
| 250 | /* move on to the next character */ |
| 251 | ctx->scroll_pos++; |
| 252 | ctx->scroll_pos %= ctx->message_len; |
| 253 | |
| 254 | /* rearm the timer */ |
| 255 | if (ctx->message_len > ctx->cfg->num_chars) |
| 256 | mod_timer(&ctx->timer, jiffies + ctx->scroll_rate); |
| 257 | } |
| 258 | |
| 259 | /** |
| 260 | * img_ascii_lcd_display() - set the message to be displayed |
| 261 | * @ctx: pointer to the private data structure |
| 262 | * @msg: the message to display |
| 263 | * @count: length of msg, or -1 |
| 264 | * |
| 265 | * Display a new message @msg on the LCD. @msg can be longer than the number of |
| 266 | * characters the LCD can display, in which case it will begin scrolling across |
| 267 | * the LCD display. |
| 268 | * |
| 269 | * Return: 0 on success, -ENOMEM on memory allocation failure |
| 270 | */ |
| 271 | static int img_ascii_lcd_display(struct img_ascii_lcd_ctx *ctx, |
| 272 | const char *msg, ssize_t count) |
| 273 | { |
| 274 | char *new_msg; |
| 275 | |
| 276 | /* stop the scroll timer */ |
| 277 | del_timer_sync(&ctx->timer); |
| 278 | |
| 279 | if (count == -1) |
| 280 | count = strlen(msg); |
| 281 | |
| 282 | /* if the string ends with a newline, trim it */ |
| 283 | if (msg[count - 1] == '\n') |
| 284 | count--; |
| 285 | |
| 286 | new_msg = devm_kmalloc(&ctx->pdev->dev, count + 1, GFP_KERNEL); |
| 287 | if (!new_msg) |
| 288 | return -ENOMEM; |
| 289 | |
| 290 | memcpy(new_msg, msg, count); |
| 291 | new_msg[count] = 0; |
| 292 | |
| 293 | if (ctx->message) |
| 294 | devm_kfree(&ctx->pdev->dev, ctx->message); |
| 295 | |
| 296 | ctx->message = new_msg; |
| 297 | ctx->message_len = count; |
| 298 | ctx->scroll_pos = 0; |
| 299 | |
| 300 | /* update the LCD */ |
| 301 | img_ascii_lcd_scroll((unsigned long)ctx); |
| 302 | |
| 303 | return 0; |
| 304 | } |
| 305 | |
| 306 | /** |
| 307 | * message_show() - read message via sysfs |
| 308 | * @dev: the LCD device |
| 309 | * @attr: the LCD message attribute |
| 310 | * @buf: the buffer to read the message into |
| 311 | * |
| 312 | * Read the current message being displayed or scrolled across the LCD display |
| 313 | * into @buf, for reads from sysfs. |
| 314 | * |
| 315 | * Return: the number of characters written to @buf |
| 316 | */ |
| 317 | static ssize_t message_show(struct device *dev, struct device_attribute *attr, |
| 318 | char *buf) |
| 319 | { |
| 320 | struct img_ascii_lcd_ctx *ctx = dev_get_drvdata(dev); |
| 321 | |
| 322 | return sprintf(buf, "%s\n", ctx->message); |
| 323 | } |
| 324 | |
| 325 | /** |
| 326 | * message_store() - write a new message via sysfs |
| 327 | * @dev: the LCD device |
| 328 | * @attr: the LCD message attribute |
| 329 | * @buf: the buffer containing the new message |
| 330 | * @count: the size of the message in @buf |
| 331 | * |
| 332 | * Write a new message to display or scroll across the LCD display from sysfs. |
| 333 | * |
| 334 | * Return: the size of the message on success, else -ERRNO |
| 335 | */ |
| 336 | static ssize_t message_store(struct device *dev, struct device_attribute *attr, |
| 337 | const char *buf, size_t count) |
| 338 | { |
| 339 | struct img_ascii_lcd_ctx *ctx = dev_get_drvdata(dev); |
| 340 | int err; |
| 341 | |
| 342 | err = img_ascii_lcd_display(ctx, buf, count); |
| 343 | return err ?: count; |
| 344 | } |
| 345 | |
| 346 | static DEVICE_ATTR_RW(message); |
| 347 | |
| 348 | /** |
| 349 | * img_ascii_lcd_probe() - probe an LCD display device |
| 350 | * @pdev: the LCD platform device |
| 351 | * |
| 352 | * Probe an LCD display device, ensuring that we have the required resources in |
| 353 | * order to access the LCD & setting up private data as well as sysfs files. |
| 354 | * |
| 355 | * Return: 0 on success, else -ERRNO |
| 356 | */ |
| 357 | static int img_ascii_lcd_probe(struct platform_device *pdev) |
| 358 | { |
| 359 | const struct of_device_id *match; |
| 360 | const struct img_ascii_lcd_config *cfg; |
| 361 | struct img_ascii_lcd_ctx *ctx; |
| 362 | struct resource *res; |
| 363 | int err; |
| 364 | |
| 365 | match = of_match_device(img_ascii_lcd_matches, &pdev->dev); |
| 366 | if (!match) |
| 367 | return -ENODEV; |
| 368 | |
| 369 | cfg = match->data; |
| 370 | ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx) + cfg->num_chars, |
| 371 | GFP_KERNEL); |
| 372 | if (!ctx) |
| 373 | return -ENOMEM; |
| 374 | |
| 375 | if (cfg->external_regmap) { |
| 376 | ctx->regmap = syscon_node_to_regmap(pdev->dev.parent->of_node); |
| 377 | if (IS_ERR(ctx->regmap)) |
| 378 | return PTR_ERR(ctx->regmap); |
| 379 | |
| 380 | if (of_property_read_u32(pdev->dev.of_node, "offset", |
| 381 | &ctx->offset)) |
| 382 | return -EINVAL; |
| 383 | } else { |
| 384 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 385 | ctx->base = devm_ioremap_resource(&pdev->dev, res); |
| 386 | if (IS_ERR(ctx->base)) |
| 387 | return PTR_ERR(ctx->base); |
| 388 | } |
| 389 | |
| 390 | ctx->pdev = pdev; |
| 391 | ctx->cfg = cfg; |
| 392 | ctx->message = NULL; |
| 393 | ctx->scroll_pos = 0; |
| 394 | ctx->scroll_rate = HZ / 2; |
| 395 | |
| 396 | /* initialise a timer for scrolling the message */ |
| 397 | init_timer(&ctx->timer); |
| 398 | ctx->timer.function = img_ascii_lcd_scroll; |
| 399 | ctx->timer.data = (unsigned long)ctx; |
| 400 | |
| 401 | platform_set_drvdata(pdev, ctx); |
| 402 | |
| 403 | /* display a default message */ |
| 404 | err = img_ascii_lcd_display(ctx, "Linux " UTS_RELEASE " ", -1); |
| 405 | if (err) |
| 406 | goto out_del_timer; |
| 407 | |
| 408 | err = device_create_file(&pdev->dev, &dev_attr_message); |
| 409 | if (err) |
| 410 | goto out_del_timer; |
| 411 | |
| 412 | return 0; |
| 413 | out_del_timer: |
| 414 | del_timer_sync(&ctx->timer); |
| 415 | return err; |
| 416 | } |
| 417 | |
| 418 | /** |
| 419 | * img_ascii_lcd_remove() - remove an LCD display device |
| 420 | * @pdev: the LCD platform device |
| 421 | * |
| 422 | * Remove an LCD display device, freeing private resources & ensuring that the |
| 423 | * driver stops using the LCD display registers. |
| 424 | * |
| 425 | * Return: 0 |
| 426 | */ |
| 427 | static int img_ascii_lcd_remove(struct platform_device *pdev) |
| 428 | { |
| 429 | struct img_ascii_lcd_ctx *ctx = platform_get_drvdata(pdev); |
| 430 | |
| 431 | device_remove_file(&pdev->dev, &dev_attr_message); |
| 432 | del_timer_sync(&ctx->timer); |
| 433 | return 0; |
| 434 | } |
| 435 | |
| 436 | static struct platform_driver img_ascii_lcd_driver = { |
| 437 | .driver = { |
| 438 | .name = "img-ascii-lcd", |
| 439 | .of_match_table = img_ascii_lcd_matches, |
| 440 | }, |
| 441 | .probe = img_ascii_lcd_probe, |
| 442 | .remove = img_ascii_lcd_remove, |
| 443 | }; |
| 444 | module_platform_driver(img_ascii_lcd_driver); |