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1 | /* arch/arm/plat-s3c24xx/adc.c |
2 | * | |
3 | * Copyright (c) 2008 Simtec Electronics | |
4 | * http://armlinux.simtec.co.uk/ | |
5 | * Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org> | |
6 | * | |
7 | * S3C24XX ADC device core | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License. | |
12 | */ | |
13 | ||
14 | #include <linux/module.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/platform_device.h> | |
17 | #include <linux/list.h> | |
18 | #include <linux/err.h> | |
19 | #include <linux/clk.h> | |
20 | #include <linux/interrupt.h> | |
21 | #include <linux/io.h> | |
22 | ||
23 | #include <plat/regs-adc.h> | |
24 | #include <plat/adc.h> | |
25 | ||
26 | /* This driver is designed to control the usage of the ADC block between | |
27 | * the touchscreen and any other drivers that may need to use it, such as | |
28 | * the hwmon driver. | |
29 | * | |
30 | * Priority will be given to the touchscreen driver, but as this itself is | |
31 | * rate limited it should not starve other requests which are processed in | |
32 | * order that they are received. | |
33 | * | |
34 | * Each user registers to get a client block which uniquely identifies it | |
35 | * and stores information such as the necessary functions to callback when | |
36 | * action is required. | |
37 | */ | |
38 | ||
39 | struct s3c_adc_client { | |
40 | struct platform_device *pdev; | |
41 | struct list_head pend; | |
42 | ||
43 | unsigned int nr_samples; | |
44 | unsigned char is_ts; | |
45 | unsigned char channel; | |
46 | ||
47 | void (*select_cb)(unsigned selected); | |
48 | void (*convert_cb)(unsigned val1, unsigned val2); | |
49 | }; | |
50 | ||
51 | struct adc_device { | |
52 | struct platform_device *pdev; | |
53 | struct platform_device *owner; | |
54 | struct clk *clk; | |
55 | struct s3c_adc_client *cur; | |
56 | struct s3c_adc_client *ts_pend; | |
57 | void __iomem *regs; | |
58 | ||
59 | unsigned int prescale; | |
60 | ||
61 | int irq; | |
62 | }; | |
63 | ||
64 | static struct adc_device *adc_dev; | |
65 | ||
66 | static LIST_HEAD(adc_pending); | |
67 | ||
68 | #define adc_dbg(_adc, msg...) dev_dbg(&(_adc)->pdev->dev, msg) | |
69 | ||
70 | static inline void s3c_adc_convert(struct adc_device *adc) | |
71 | { | |
72 | unsigned con = readl(adc->regs + S3C2410_ADCCON); | |
73 | ||
74 | con |= S3C2410_ADCCON_ENABLE_START; | |
75 | writel(con, adc->regs + S3C2410_ADCCON); | |
76 | } | |
77 | ||
78 | static inline void s3c_adc_select(struct adc_device *adc, | |
79 | struct s3c_adc_client *client) | |
80 | { | |
81 | unsigned con = readl(adc->regs + S3C2410_ADCCON); | |
82 | ||
83 | client->select_cb(1); | |
84 | ||
85 | con &= ~S3C2410_ADCCON_MUXMASK; | |
86 | con &= ~S3C2410_ADCCON_STDBM; | |
87 | con &= ~S3C2410_ADCCON_STARTMASK; | |
88 | ||
89 | if (!client->is_ts) | |
90 | con |= S3C2410_ADCCON_SELMUX(client->channel); | |
91 | ||
92 | writel(con, adc->regs + S3C2410_ADCCON); | |
93 | } | |
94 | ||
95 | static void s3c_adc_dbgshow(struct adc_device *adc) | |
96 | { | |
97 | adc_dbg(adc, "CON=%08x, TSC=%08x, DLY=%08x\n", | |
98 | readl(adc->regs + S3C2410_ADCCON), | |
99 | readl(adc->regs + S3C2410_ADCTSC), | |
100 | readl(adc->regs + S3C2410_ADCDLY)); | |
101 | } | |
102 | ||
103 | void s3c_adc_try(struct adc_device *adc) | |
104 | { | |
105 | struct s3c_adc_client *next = adc->ts_pend; | |
106 | ||
107 | if (!next && !list_empty(&adc_pending)) { | |
108 | next = list_first_entry(&adc_pending, | |
109 | struct s3c_adc_client, pend); | |
110 | list_del(&next->pend); | |
111 | } else | |
112 | adc->ts_pend = NULL; | |
113 | ||
114 | if (next) { | |
115 | adc_dbg(adc, "new client is %p\n", next); | |
116 | adc->cur = next; | |
117 | s3c_adc_select(adc, next); | |
118 | s3c_adc_convert(adc); | |
119 | s3c_adc_dbgshow(adc); | |
120 | } | |
121 | } | |
122 | ||
123 | int s3c_adc_start(struct s3c_adc_client *client, | |
124 | unsigned int channel, unsigned int nr_samples) | |
125 | { | |
126 | struct adc_device *adc = adc_dev; | |
127 | unsigned long flags; | |
128 | ||
129 | if (!adc) { | |
130 | printk(KERN_ERR "%s: failed to find adc\n", __func__); | |
131 | return -EINVAL; | |
132 | } | |
133 | ||
134 | if (client->is_ts && adc->ts_pend) | |
135 | return -EAGAIN; | |
136 | ||
137 | local_irq_save(flags); | |
138 | ||
139 | client->channel = channel; | |
140 | client->nr_samples = nr_samples; | |
141 | ||
142 | if (client->is_ts) | |
143 | adc->ts_pend = client; | |
144 | else | |
145 | list_add_tail(&client->pend, &adc_pending); | |
146 | ||
147 | if (!adc->cur) | |
148 | s3c_adc_try(adc); | |
149 | local_irq_restore(flags); | |
150 | ||
151 | return 0; | |
152 | } | |
153 | EXPORT_SYMBOL_GPL(s3c_adc_start); | |
154 | ||
155 | static void s3c_adc_default_select(unsigned select) | |
156 | { | |
157 | } | |
158 | ||
159 | struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev, | |
160 | void (*select)(unsigned int selected), | |
161 | void (*conv)(unsigned d0, unsigned d1), | |
162 | unsigned int is_ts) | |
163 | { | |
164 | struct s3c_adc_client *client; | |
165 | ||
166 | WARN_ON(!pdev); | |
167 | WARN_ON(!conv); | |
168 | ||
169 | if (!select) | |
170 | select = s3c_adc_default_select; | |
171 | ||
172 | if (!conv || !pdev) | |
173 | return ERR_PTR(-EINVAL); | |
174 | ||
175 | client = kzalloc(sizeof(struct s3c_adc_client), GFP_KERNEL); | |
176 | if (!client) { | |
177 | dev_err(&pdev->dev, "no memory for adc client\n"); | |
178 | return ERR_PTR(-ENOMEM); | |
179 | } | |
180 | ||
181 | client->pdev = pdev; | |
182 | client->is_ts = is_ts; | |
183 | client->select_cb = select; | |
184 | client->convert_cb = conv; | |
185 | ||
186 | return client; | |
187 | } | |
188 | EXPORT_SYMBOL_GPL(s3c_adc_register); | |
189 | ||
190 | void s3c_adc_release(struct s3c_adc_client *client) | |
191 | { | |
192 | /* We should really check that nothing is in progress. */ | |
193 | kfree(client); | |
194 | } | |
195 | EXPORT_SYMBOL_GPL(s3c_adc_release); | |
196 | ||
197 | static irqreturn_t s3c_adc_irq(int irq, void *pw) | |
198 | { | |
199 | struct adc_device *adc = pw; | |
200 | struct s3c_adc_client *client = adc->cur; | |
201 | unsigned long flags; | |
202 | unsigned data0, data1; | |
203 | ||
204 | if (!client) { | |
205 | dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__); | |
206 | return IRQ_HANDLED; | |
207 | } | |
208 | ||
209 | data0 = readl(adc->regs + S3C2410_ADCDAT0); | |
210 | data1 = readl(adc->regs + S3C2410_ADCDAT1); | |
211 | adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1); | |
212 | ||
213 | (client->convert_cb)(data0 & 0x3ff, data1 & 0x3ff); | |
214 | ||
215 | if (--client->nr_samples > 0) { | |
216 | /* fire another conversion for this */ | |
217 | ||
218 | client->select_cb(1); | |
219 | s3c_adc_convert(adc); | |
220 | } else { | |
221 | local_irq_save(flags); | |
222 | (client->select_cb)(0); | |
223 | adc->cur = NULL; | |
224 | ||
225 | s3c_adc_try(adc); | |
226 | local_irq_restore(flags); | |
227 | } | |
228 | ||
229 | return IRQ_HANDLED; | |
230 | } | |
231 | ||
232 | static int s3c_adc_probe(struct platform_device *pdev) | |
233 | { | |
234 | struct device *dev = &pdev->dev; | |
235 | struct adc_device *adc; | |
236 | struct resource *regs; | |
237 | int ret; | |
238 | ||
239 | adc = kzalloc(sizeof(struct adc_device), GFP_KERNEL); | |
240 | if (adc == NULL) { | |
241 | dev_err(dev, "failed to allocate adc_device\n"); | |
242 | return -ENOMEM; | |
243 | } | |
244 | ||
245 | adc->pdev = pdev; | |
246 | adc->prescale = S3C2410_ADCCON_PRSCVL(49); | |
247 | ||
248 | adc->irq = platform_get_irq(pdev, 1); | |
249 | if (adc->irq <= 0) { | |
250 | dev_err(dev, "failed to get adc irq\n"); | |
251 | ret = -ENOENT; | |
252 | goto err_alloc; | |
253 | } | |
254 | ||
255 | ret = request_irq(adc->irq, s3c_adc_irq, 0, dev_name(dev), adc); | |
256 | if (ret < 0) { | |
257 | dev_err(dev, "failed to attach adc irq\n"); | |
258 | goto err_alloc; | |
259 | } | |
260 | ||
261 | adc->clk = clk_get(dev, "adc"); | |
262 | if (IS_ERR(adc->clk)) { | |
263 | dev_err(dev, "failed to get adc clock\n"); | |
264 | ret = PTR_ERR(adc->clk); | |
265 | goto err_irq; | |
266 | } | |
267 | ||
268 | regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
269 | if (!regs) { | |
270 | dev_err(dev, "failed to find registers\n"); | |
271 | ret = -ENXIO; | |
272 | goto err_clk; | |
273 | } | |
274 | ||
275 | adc->regs = ioremap(regs->start, resource_size(regs)); | |
276 | if (!adc->regs) { | |
277 | dev_err(dev, "failed to map registers\n"); | |
278 | ret = -ENXIO; | |
279 | goto err_clk; | |
280 | } | |
281 | ||
282 | clk_enable(adc->clk); | |
283 | ||
284 | writel(adc->prescale | S3C2410_ADCCON_PRSCEN, | |
285 | adc->regs + S3C2410_ADCCON); | |
286 | ||
287 | dev_info(dev, "attached adc driver\n"); | |
288 | ||
289 | platform_set_drvdata(pdev, adc); | |
290 | adc_dev = adc; | |
291 | ||
292 | return 0; | |
293 | ||
294 | err_clk: | |
295 | clk_put(adc->clk); | |
296 | ||
297 | err_irq: | |
298 | free_irq(adc->irq, adc); | |
299 | ||
300 | err_alloc: | |
301 | kfree(adc); | |
302 | return ret; | |
303 | } | |
304 | ||
305 | static int s3c_adc_remove(struct platform_device *pdev) | |
306 | { | |
307 | struct adc_device *adc = platform_get_drvdata(pdev); | |
308 | ||
309 | iounmap(adc->regs); | |
310 | free_irq(adc->irq, adc); | |
311 | clk_disable(adc->clk); | |
312 | clk_put(adc->clk); | |
313 | kfree(adc); | |
314 | ||
315 | return 0; | |
316 | } | |
317 | ||
318 | #ifdef CONFIG_PM | |
319 | static int s3c_adc_suspend(struct platform_device *pdev, pm_message_t state) | |
320 | { | |
321 | struct adc_device *adc = platform_get_drvdata(pdev); | |
322 | u32 con; | |
323 | ||
324 | con = readl(adc->regs + S3C2410_ADCCON); | |
325 | con |= S3C2410_ADCCON_STDBM; | |
326 | writel(con, adc->regs + S3C2410_ADCCON); | |
327 | ||
328 | clk_disable(adc->clk); | |
329 | ||
330 | return 0; | |
331 | } | |
332 | ||
333 | static int s3c_adc_resume(struct platform_device *pdev) | |
334 | { | |
335 | struct adc_device *adc = platform_get_drvdata(pdev); | |
336 | ||
337 | clk_enable(adc->clk); | |
338 | ||
339 | writel(adc->prescale | S3C2410_ADCCON_PRSCEN, | |
340 | adc->regs + S3C2410_ADCCON); | |
341 | ||
342 | return 0; | |
343 | } | |
344 | ||
345 | #else | |
346 | #define s3c_adc_suspend NULL | |
347 | #define s3c_adc_resume NULL | |
348 | #endif | |
349 | ||
350 | static struct platform_driver s3c_adc_driver = { | |
351 | .driver = { | |
352 | .name = "s3c24xx-adc", | |
353 | .owner = THIS_MODULE, | |
354 | }, | |
355 | .probe = s3c_adc_probe, | |
356 | .remove = __devexit_p(s3c_adc_remove), | |
357 | .suspend = s3c_adc_suspend, | |
358 | .resume = s3c_adc_resume, | |
359 | }; | |
360 | ||
361 | static int __init adc_init(void) | |
362 | { | |
363 | int ret; | |
364 | ||
365 | ret = platform_driver_register(&s3c_adc_driver); | |
366 | if (ret) | |
367 | printk(KERN_ERR "%s: failed to add adc driver\n", __func__); | |
368 | ||
369 | return ret; | |
370 | } | |
371 | ||
372 | arch_initcall(adc_init); |