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