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10#include <linux/init.h>
11#include <linux/interrupt.h>
12#include <linux/platform_device.h>
13#include <linux/of.h>
14#include <linux/completion.h>
15#include <linux/delay.h>
16#include <linux/io.h>
17#include <linux/slab.h>
18#include <linux/workqueue.h>
19#include <generated/utsrelease.h>
20
21#define DRIVERNAME "arm-charlcd"
22#define CHARLCD_TIMEOUT (msecs_to_jiffies(1000))
23
24
25#define CHAR_COM 0x00U
26#define CHAR_DAT 0x04U
27#define CHAR_RD 0x08U
28#define CHAR_RAW 0x0CU
29#define CHAR_MASK 0x10U
30#define CHAR_STAT 0x14U
31
32#define CHAR_RAW_CLEAR 0x00000000U
33#define CHAR_RAW_VALID 0x00000100U
34
35
36#define HD_CLEAR 0x01U
37#define HD_HOME 0x02U
38#define HD_ENTRYMODE 0x04U
39#define HD_ENTRYMODE_INCREMENT 0x02U
40#define HD_ENTRYMODE_SHIFT 0x01U
41#define HD_DISPCTRL 0x08U
42#define HD_DISPCTRL_ON 0x04U
43#define HD_DISPCTRL_CURSOR_ON 0x02U
44#define HD_DISPCTRL_CURSOR_BLINK 0x01U
45#define HD_CRSR_SHIFT 0x10U
46#define HD_CRSR_SHIFT_DISPLAY 0x08U
47#define HD_CRSR_SHIFT_DISPLAY_RIGHT 0x04U
48#define HD_FUNCSET 0x20U
49#define HD_FUNCSET_8BIT 0x10U
50#define HD_FUNCSET_2_LINES 0x08U
51#define HD_FUNCSET_FONT_5X10 0x04U
52#define HD_SET_CGRAM 0x40U
53#define HD_SET_DDRAM 0x80U
54#define HD_BUSY_FLAG 0x80U
55
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61
62
63
64struct charlcd {
65 struct device *dev;
66 u32 phybase;
67 u32 physize;
68 void __iomem *virtbase;
69 int irq;
70 struct completion complete;
71 struct delayed_work init_work;
72};
73
74static irqreturn_t charlcd_interrupt(int irq, void *data)
75{
76 struct charlcd *lcd = data;
77 u8 status;
78
79 status = readl(lcd->virtbase + CHAR_STAT) & 0x01;
80
81 writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
82 if (status)
83 complete(&lcd->complete);
84 else
85 dev_info(lcd->dev, "Spurious IRQ (%02x)\n", status);
86 return IRQ_HANDLED;
87}
88
89
90static void charlcd_wait_complete_irq(struct charlcd *lcd)
91{
92 int ret;
93
94 ret = wait_for_completion_interruptible_timeout(&lcd->complete,
95 CHARLCD_TIMEOUT);
96
97 writel(0x00, lcd->virtbase + CHAR_MASK);
98
99 if (ret < 0) {
100 dev_err(lcd->dev,
101 "wait_for_completion_interruptible_timeout() "
102 "returned %d waiting for ready\n", ret);
103 return;
104 }
105
106 if (ret == 0) {
107 dev_err(lcd->dev, "charlcd controller timed out "
108 "waiting for ready\n");
109 return;
110 }
111}
112
113static u8 charlcd_4bit_read_char(struct charlcd *lcd)
114{
115 u8 data;
116 u32 val;
117 int i;
118
119
120 if (lcd->irq >= 0)
121 charlcd_wait_complete_irq(lcd);
122 else {
123 i = 0;
124 val = 0;
125 while (!(val & CHAR_RAW_VALID) && i < 10) {
126 udelay(100);
127 val = readl(lcd->virtbase + CHAR_RAW);
128 i++;
129 }
130
131 writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
132 }
133 msleep(1);
134
135
136 data = readl(lcd->virtbase + CHAR_RD) & 0xf0;
137
138
139
140
141
142 i = 0;
143 val = 0;
144 while (!(val & CHAR_RAW_VALID) && i < 10) {
145 udelay(100);
146 val = readl(lcd->virtbase + CHAR_RAW);
147 i++;
148 }
149 writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
150 msleep(1);
151
152
153 data |= (readl(lcd->virtbase + CHAR_RD) >> 4) & 0x0f;
154
155 return data;
156}
157
158static bool charlcd_4bit_read_bf(struct charlcd *lcd)
159{
160 if (lcd->irq >= 0) {
161
162
163
164
165 writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
166 init_completion(&lcd->complete);
167 writel(0x01, lcd->virtbase + CHAR_MASK);
168 }
169 readl(lcd->virtbase + CHAR_COM);
170 return charlcd_4bit_read_char(lcd) & HD_BUSY_FLAG ? true : false;
171}
172
173static void charlcd_4bit_wait_busy(struct charlcd *lcd)
174{
175 int retries = 50;
176
177 udelay(100);
178 while (charlcd_4bit_read_bf(lcd) && retries)
179 retries--;
180 if (!retries)
181 dev_err(lcd->dev, "timeout waiting for busyflag\n");
182}
183
184static void charlcd_4bit_command(struct charlcd *lcd, u8 cmd)
185{
186 u32 cmdlo = (cmd << 4) & 0xf0;
187 u32 cmdhi = (cmd & 0xf0);
188
189 writel(cmdhi, lcd->virtbase + CHAR_COM);
190 udelay(10);
191 writel(cmdlo, lcd->virtbase + CHAR_COM);
192 charlcd_4bit_wait_busy(lcd);
193}
194
195static void charlcd_4bit_char(struct charlcd *lcd, u8 ch)
196{
197 u32 chlo = (ch << 4) & 0xf0;
198 u32 chhi = (ch & 0xf0);
199
200 writel(chhi, lcd->virtbase + CHAR_DAT);
201 udelay(10);
202 writel(chlo, lcd->virtbase + CHAR_DAT);
203 charlcd_4bit_wait_busy(lcd);
204}
205
206static void charlcd_4bit_print(struct charlcd *lcd, int line, const char *str)
207{
208 u8 offset;
209 int i;
210
211
212
213
214
215
216 if (line == 0)
217 offset = 0;
218 else if (line == 1)
219 offset = 0x28;
220 else
221 return;
222
223
224 charlcd_4bit_command(lcd, HD_SET_DDRAM | offset);
225
226
227 for (i = 0; i < strlen(str) && i < 0x28; i++)
228 charlcd_4bit_char(lcd, str[i]);
229}
230
231static void charlcd_4bit_init(struct charlcd *lcd)
232{
233
234 writel(HD_FUNCSET | HD_FUNCSET_8BIT, lcd->virtbase + CHAR_COM);
235 msleep(5);
236 writel(HD_FUNCSET | HD_FUNCSET_8BIT, lcd->virtbase + CHAR_COM);
237 udelay(100);
238 writel(HD_FUNCSET | HD_FUNCSET_8BIT, lcd->virtbase + CHAR_COM);
239 udelay(100);
240
241 writel(HD_FUNCSET, lcd->virtbase + CHAR_COM);
242 udelay(100);
243
244
245
246
247 charlcd_4bit_command(lcd, HD_FUNCSET | HD_FUNCSET_2_LINES);
248 charlcd_4bit_command(lcd, HD_DISPCTRL | HD_DISPCTRL_ON);
249 charlcd_4bit_command(lcd, HD_ENTRYMODE | HD_ENTRYMODE_INCREMENT);
250 charlcd_4bit_command(lcd, HD_CLEAR);
251 charlcd_4bit_command(lcd, HD_HOME);
252
253 charlcd_4bit_print(lcd, 0, "ARM Linux");
254 charlcd_4bit_print(lcd, 1, UTS_RELEASE);
255}
256
257static void charlcd_init_work(struct work_struct *work)
258{
259 struct charlcd *lcd =
260 container_of(work, struct charlcd, init_work.work);
261
262 charlcd_4bit_init(lcd);
263}
264
265static int __init charlcd_probe(struct platform_device *pdev)
266{
267 int ret;
268 struct charlcd *lcd;
269 struct resource *res;
270
271 lcd = kzalloc(sizeof(struct charlcd), GFP_KERNEL);
272 if (!lcd)
273 return -ENOMEM;
274
275 lcd->dev = &pdev->dev;
276
277 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
278 if (!res) {
279 ret = -ENOENT;
280 goto out_no_resource;
281 }
282 lcd->phybase = res->start;
283 lcd->physize = resource_size(res);
284
285 if (request_mem_region(lcd->phybase, lcd->physize,
286 DRIVERNAME) == NULL) {
287 ret = -EBUSY;
288 goto out_no_memregion;
289 }
290
291 lcd->virtbase = ioremap(lcd->phybase, lcd->physize);
292 if (!lcd->virtbase) {
293 ret = -ENOMEM;
294 goto out_no_memregion;
295 }
296
297 lcd->irq = platform_get_irq(pdev, 0);
298
299 if (lcd->irq >= 0) {
300 if (request_irq(lcd->irq, charlcd_interrupt, 0,
301 DRIVERNAME, lcd)) {
302 ret = -EIO;
303 goto out_no_irq;
304 }
305 }
306
307 platform_set_drvdata(pdev, lcd);
308
309
310
311
312
313 INIT_DELAYED_WORK(&lcd->init_work, charlcd_init_work);
314 schedule_delayed_work(&lcd->init_work, 0);
315
316 dev_info(&pdev->dev, "initialized ARM character LCD at %08x\n",
317 lcd->phybase);
318
319 return 0;
320
321out_no_irq:
322 iounmap(lcd->virtbase);
323out_no_memregion:
324 release_mem_region(lcd->phybase, SZ_4K);
325out_no_resource:
326 kfree(lcd);
327 return ret;
328}
329
330static int charlcd_suspend(struct device *dev)
331{
332 struct platform_device *pdev = to_platform_device(dev);
333 struct charlcd *lcd = platform_get_drvdata(pdev);
334
335
336 charlcd_4bit_command(lcd, HD_DISPCTRL);
337 return 0;
338}
339
340static int charlcd_resume(struct device *dev)
341{
342 struct platform_device *pdev = to_platform_device(dev);
343 struct charlcd *lcd = platform_get_drvdata(pdev);
344
345
346 charlcd_4bit_command(lcd, HD_DISPCTRL | HD_DISPCTRL_ON);
347 return 0;
348}
349
350static const struct dev_pm_ops charlcd_pm_ops = {
351 .suspend = charlcd_suspend,
352 .resume = charlcd_resume,
353};
354
355static const struct of_device_id charlcd_match[] = {
356 { .compatible = "arm,versatile-lcd", },
357 {}
358};
359
360static struct platform_driver charlcd_driver = {
361 .driver = {
362 .name = DRIVERNAME,
363 .pm = &charlcd_pm_ops,
364 .suppress_bind_attrs = true,
365 .of_match_table = of_match_ptr(charlcd_match),
366 },
367};
368builtin_platform_driver_probe(charlcd_driver, charlcd_probe);
369
