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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2016 Imagination Technologies
4 * Author: Paul Burton <paul.burton@mips.com>
5 */
6
7#include <linux/kernel.h>
8#include <linux/io.h>
9#include <linux/mfd/syscon.h>
10#include <linux/module.h>
11#include <linux/of.h>
12#include <linux/platform_device.h>
13#include <linux/property.h>
14#include <linux/regmap.h>
15#include <linux/slab.h>
16
17#include "line-display.h"
18
19struct img_ascii_lcd_ctx;
20
21/**
22 * struct img_ascii_lcd_config - Configuration information about an LCD model
23 * @num_chars: the number of characters the LCD can display
24 * @external_regmap: true if registers are in a system controller, else false
25 * @update: function called to update the LCD
26 */
27struct img_ascii_lcd_config {
28 unsigned int num_chars;
29 bool external_regmap;
30 void (*update)(struct linedisp *linedisp);
31};
32
33/**
34 * struct img_ascii_lcd_ctx - Private data structure
35 * @base: the base address of the LCD registers
36 * @regmap: the regmap through which LCD registers are accessed
37 * @offset: the offset within regmap to the start of the LCD registers
38 * @cfg: pointer to the LCD model configuration
39 * @linedisp: line display structure
40 * @curr: the string currently displayed on the LCD
41 */
42struct img_ascii_lcd_ctx {
43 union {
44 void __iomem *base;
45 struct regmap *regmap;
46 };
47 u32 offset;
48 const struct img_ascii_lcd_config *cfg;
49 struct linedisp linedisp;
50 char curr[] __aligned(8);
51};
52
53/*
54 * MIPS Boston development board
55 */
56
57static void boston_update(struct linedisp *linedisp)
58{
59 struct img_ascii_lcd_ctx *ctx =
60 container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
61 ulong val;
62
63#if BITS_PER_LONG == 64
64 val = *((u64 *)&ctx->curr[0]);
65 __raw_writeq(val, ctx->base);
66#elif BITS_PER_LONG == 32
67 val = *((u32 *)&ctx->curr[0]);
68 __raw_writel(val, ctx->base);
69 val = *((u32 *)&ctx->curr[4]);
70 __raw_writel(val, ctx->base + 4);
71#else
72# error Not 32 or 64 bit
73#endif
74}
75
76static struct img_ascii_lcd_config boston_config = {
77 .num_chars = 8,
78 .update = boston_update,
79};
80
81/*
82 * MIPS Malta development board
83 */
84
85static void malta_update(struct linedisp *linedisp)
86{
87 struct img_ascii_lcd_ctx *ctx =
88 container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
89 unsigned int i;
90 int err = 0;
91
92 for (i = 0; i < linedisp->num_chars; i++) {
93 err = regmap_write(ctx->regmap,
94 ctx->offset + (i * 8), ctx->curr[i]);
95 if (err)
96 break;
97 }
98
99 if (unlikely(err))
100 pr_err_ratelimited("Failed to update LCD display: %d\n", err);
101}
102
103static struct img_ascii_lcd_config malta_config = {
104 .num_chars = 8,
105 .external_regmap = true,
106 .update = malta_update,
107};
108
109/*
110 * MIPS SEAD3 development board
111 */
112
113enum {
114 SEAD3_REG_LCD_CTRL = 0x00,
115#define SEAD3_REG_LCD_CTRL_SETDRAM BIT(7)
116 SEAD3_REG_LCD_DATA = 0x08,
117 SEAD3_REG_CPLD_STATUS = 0x10,
118#define SEAD3_REG_CPLD_STATUS_BUSY BIT(0)
119 SEAD3_REG_CPLD_DATA = 0x18,
120#define SEAD3_REG_CPLD_DATA_BUSY BIT(7)
121};
122
123static int sead3_wait_sm_idle(struct img_ascii_lcd_ctx *ctx)
124{
125 unsigned int status;
126 int err;
127
128 do {
129 err = regmap_read(ctx->regmap,
130 ctx->offset + SEAD3_REG_CPLD_STATUS,
131 &status);
132 if (err)
133 return err;
134 } while (status & SEAD3_REG_CPLD_STATUS_BUSY);
135
136 return 0;
137
138}
139
140static int sead3_wait_lcd_idle(struct img_ascii_lcd_ctx *ctx)
141{
142 unsigned int cpld_data;
143 int err;
144
145 err = sead3_wait_sm_idle(ctx);
146 if (err)
147 return err;
148
149 do {
150 err = regmap_read(ctx->regmap,
151 ctx->offset + SEAD3_REG_LCD_CTRL,
152 &cpld_data);
153 if (err)
154 return err;
155
156 err = sead3_wait_sm_idle(ctx);
157 if (err)
158 return err;
159
160 err = regmap_read(ctx->regmap,
161 ctx->offset + SEAD3_REG_CPLD_DATA,
162 &cpld_data);
163 if (err)
164 return err;
165 } while (cpld_data & SEAD3_REG_CPLD_DATA_BUSY);
166
167 return 0;
168}
169
170static void sead3_update(struct linedisp *linedisp)
171{
172 struct img_ascii_lcd_ctx *ctx =
173 container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
174 unsigned int i;
175 int err = 0;
176
177 for (i = 0; i < linedisp->num_chars; i++) {
178 err = sead3_wait_lcd_idle(ctx);
179 if (err)
180 break;
181
182 err = regmap_write(ctx->regmap,
183 ctx->offset + SEAD3_REG_LCD_CTRL,
184 SEAD3_REG_LCD_CTRL_SETDRAM | i);
185 if (err)
186 break;
187
188 err = sead3_wait_lcd_idle(ctx);
189 if (err)
190 break;
191
192 err = regmap_write(ctx->regmap,
193 ctx->offset + SEAD3_REG_LCD_DATA,
194 ctx->curr[i]);
195 if (err)
196 break;
197 }
198
199 if (unlikely(err))
200 pr_err_ratelimited("Failed to update LCD display: %d\n", err);
201}
202
203static struct img_ascii_lcd_config sead3_config = {
204 .num_chars = 16,
205 .external_regmap = true,
206 .update = sead3_update,
207};
208
209static const struct of_device_id img_ascii_lcd_matches[] = {
210 { .compatible = "img,boston-lcd", .data = &boston_config },
211 { .compatible = "mti,malta-lcd", .data = &malta_config },
212 { .compatible = "mti,sead3-lcd", .data = &sead3_config },
213 { /* sentinel */ }
214};
215MODULE_DEVICE_TABLE(of, img_ascii_lcd_matches);
216
217/**
218 * img_ascii_lcd_probe() - probe an LCD display device
219 * @pdev: the LCD platform device
220 *
221 * Probe an LCD display device, ensuring that we have the required resources in
222 * order to access the LCD & setting up private data as well as sysfs files.
223 *
224 * Return: 0 on success, else -ERRNO
225 */
226static int img_ascii_lcd_probe(struct platform_device *pdev)
227{
228 struct device *dev = &pdev->dev;
229 const struct img_ascii_lcd_config *cfg = device_get_match_data(dev);
230 struct img_ascii_lcd_ctx *ctx;
231 int err;
232
233 ctx = devm_kzalloc(dev, sizeof(*ctx) + cfg->num_chars, GFP_KERNEL);
234 if (!ctx)
235 return -ENOMEM;
236
237 if (cfg->external_regmap) {
238 ctx->regmap = syscon_node_to_regmap(dev->parent->of_node);
239 if (IS_ERR(ctx->regmap))
240 return PTR_ERR(ctx->regmap);
241
242 if (of_property_read_u32(dev->of_node, "offset", &ctx->offset))
243 return -EINVAL;
244 } else {
245 ctx->base = devm_platform_ioremap_resource(pdev, 0);
246 if (IS_ERR(ctx->base))
247 return PTR_ERR(ctx->base);
248 }
249
250 err = linedisp_register(&ctx->linedisp, dev, cfg->num_chars, ctx->curr,
251 cfg->update);
252 if (err)
253 return err;
254
255 /* for backwards compatibility */
256 err = compat_only_sysfs_link_entry_to_kobj(&dev->kobj,
257 &ctx->linedisp.dev.kobj,
258 "message", NULL);
259 if (err)
260 goto err_unregister;
261
262 platform_set_drvdata(pdev, ctx);
263 return 0;
264
265err_unregister:
266 linedisp_unregister(&ctx->linedisp);
267 return err;
268}
269
270/**
271 * img_ascii_lcd_remove() - remove an LCD display device
272 * @pdev: the LCD platform device
273 *
274 * Remove an LCD display device, freeing private resources & ensuring that the
275 * driver stops using the LCD display registers.
276 *
277 * Return: 0
278 */
279static int img_ascii_lcd_remove(struct platform_device *pdev)
280{
281 struct img_ascii_lcd_ctx *ctx = platform_get_drvdata(pdev);
282
283 sysfs_remove_link(&pdev->dev.kobj, "message");
284 linedisp_unregister(&ctx->linedisp);
285 return 0;
286}
287
288static struct platform_driver img_ascii_lcd_driver = {
289 .driver = {
290 .name = "img-ascii-lcd",
291 .of_match_table = img_ascii_lcd_matches,
292 },
293 .probe = img_ascii_lcd_probe,
294 .remove = img_ascii_lcd_remove,
295};
296module_platform_driver(img_ascii_lcd_driver);
297
298MODULE_DESCRIPTION("Imagination Technologies ASCII LCD Display");
299MODULE_AUTHOR("Paul Burton <paul.burton@mips.com>");
300MODULE_LICENSE("GPL");
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
23struct 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 */
31struct 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 */
51struct 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
71static 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
88static 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
97static 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
113static 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
123enum {
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
133static 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
150static 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
180static 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
211static struct img_ascii_lcd_config sead3_config = {
212 .num_chars = 16,
213 .external_regmap = true,
214 .update = sead3_update,
215};
216
217static 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 },
221 { /* sentinel */ }
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 */
231static 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 */
271static 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 */
317static 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 */
336static 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
346static 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 */
357static 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;
413out_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 */
427static 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
436static 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};
444module_platform_driver(img_ascii_lcd_driver);