Root/arch/arm/plat-samsung/adc.c

1/* arch/arm/plat-samsung/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 * Samsung 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/sched.h>
18#include <linux/list.h>
19#include <linux/slab.h>
20#include <linux/err.h>
21#include <linux/clk.h>
22#include <linux/interrupt.h>
23#include <linux/io.h>
24
25#include <plat/regs-adc.h>
26#include <plat/adc.h>
27
28/* This driver is designed to control the usage of the ADC block between
29 * the touchscreen and any other drivers that may need to use it, such as
30 * the hwmon driver.
31 *
32 * Priority will be given to the touchscreen driver, but as this itself is
33 * rate limited it should not starve other requests which are processed in
34 * order that they are received.
35 *
36 * Each user registers to get a client block which uniquely identifies it
37 * and stores information such as the necessary functions to callback when
38 * action is required.
39 */
40
41enum s3c_cpu_type {
42    TYPE_S3C24XX,
43    TYPE_S3C64XX
44};
45
46struct s3c_adc_client {
47    struct platform_device *pdev;
48    struct list_head pend;
49    wait_queue_head_t *wait;
50
51    unsigned int nr_samples;
52    int result;
53    unsigned char is_ts;
54    unsigned char channel;
55
56    void (*select_cb)(struct s3c_adc_client *c, unsigned selected);
57    void (*convert_cb)(struct s3c_adc_client *c,
58                  unsigned val1, unsigned val2,
59                  unsigned *samples_left);
60};
61
62struct adc_device {
63    struct platform_device *pdev;
64    struct platform_device *owner;
65    struct clk *clk;
66    struct s3c_adc_client *cur;
67    struct s3c_adc_client *ts_pend;
68    void __iomem *regs;
69    spinlock_t lock;
70
71    unsigned int prescale;
72
73    int irq;
74};
75
76static struct adc_device *adc_dev;
77
78static LIST_HEAD(adc_pending); /* protected by adc_device.lock */
79
80#define adc_dbg(_adc, msg...) dev_dbg(&(_adc)->pdev->dev, msg)
81
82static inline void s3c_adc_convert(struct adc_device *adc)
83{
84    unsigned con = readl(adc->regs + S3C2410_ADCCON);
85
86    con |= S3C2410_ADCCON_ENABLE_START;
87    writel(con, adc->regs + S3C2410_ADCCON);
88}
89
90static inline void s3c_adc_select(struct adc_device *adc,
91                  struct s3c_adc_client *client)
92{
93    unsigned con = readl(adc->regs + S3C2410_ADCCON);
94
95    client->select_cb(client, 1);
96
97    con &= ~S3C2410_ADCCON_MUXMASK;
98    con &= ~S3C2410_ADCCON_STDBM;
99    con &= ~S3C2410_ADCCON_STARTMASK;
100
101    if (!client->is_ts)
102        con |= S3C2410_ADCCON_SELMUX(client->channel);
103
104    writel(con, adc->regs + S3C2410_ADCCON);
105}
106
107static void s3c_adc_dbgshow(struct adc_device *adc)
108{
109    adc_dbg(adc, "CON=%08x, TSC=%08x, DLY=%08x\n",
110        readl(adc->regs + S3C2410_ADCCON),
111        readl(adc->regs + S3C2410_ADCTSC),
112        readl(adc->regs + S3C2410_ADCDLY));
113}
114
115static void s3c_adc_try(struct adc_device *adc)
116{
117    struct s3c_adc_client *next = adc->ts_pend;
118
119    if (!next && !list_empty(&adc_pending)) {
120        next = list_first_entry(&adc_pending,
121                    struct s3c_adc_client, pend);
122        list_del(&next->pend);
123    } else
124        adc->ts_pend = NULL;
125
126    if (next) {
127        adc_dbg(adc, "new client is %p\n", next);
128        adc->cur = next;
129        s3c_adc_select(adc, next);
130        s3c_adc_convert(adc);
131        s3c_adc_dbgshow(adc);
132    }
133}
134
135int s3c_adc_start(struct s3c_adc_client *client,
136          unsigned int channel, unsigned int nr_samples)
137{
138    struct adc_device *adc = adc_dev;
139    unsigned long flags;
140
141    if (!adc) {
142        printk(KERN_ERR "%s: failed to find adc\n", __func__);
143        return -EINVAL;
144    }
145
146    if (client->is_ts && adc->ts_pend)
147        return -EAGAIN;
148
149    spin_lock_irqsave(&adc->lock, flags);
150
151    client->channel = channel;
152    client->nr_samples = nr_samples;
153
154    if (client->is_ts)
155        adc->ts_pend = client;
156    else
157        list_add_tail(&client->pend, &adc_pending);
158
159    if (!adc->cur)
160        s3c_adc_try(adc);
161
162    spin_unlock_irqrestore(&adc->lock, flags);
163
164    return 0;
165}
166EXPORT_SYMBOL_GPL(s3c_adc_start);
167
168static void s3c_convert_done(struct s3c_adc_client *client,
169                 unsigned v, unsigned u, unsigned *left)
170{
171    client->result = v;
172    wake_up(client->wait);
173}
174
175int s3c_adc_read(struct s3c_adc_client *client, unsigned int ch)
176{
177    DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
178    int ret;
179
180    client->convert_cb = s3c_convert_done;
181    client->wait = &wake;
182    client->result = -1;
183
184    ret = s3c_adc_start(client, ch, 1);
185    if (ret < 0)
186        goto err;
187
188    ret = wait_event_timeout(wake, client->result >= 0, HZ / 2);
189    if (client->result < 0) {
190        ret = -ETIMEDOUT;
191        goto err;
192    }
193
194    client->convert_cb = NULL;
195    return client->result;
196
197err:
198    return ret;
199}
200EXPORT_SYMBOL_GPL(s3c_adc_read);
201
202static void s3c_adc_default_select(struct s3c_adc_client *client,
203                   unsigned select)
204{
205}
206
207struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev,
208                    void (*select)(struct s3c_adc_client *client,
209                               unsigned int selected),
210                    void (*conv)(struct s3c_adc_client *client,
211                             unsigned d0, unsigned d1,
212                             unsigned *samples_left),
213                    unsigned int is_ts)
214{
215    struct s3c_adc_client *client;
216
217    WARN_ON(!pdev);
218
219    if (!select)
220        select = s3c_adc_default_select;
221
222    if (!pdev)
223        return ERR_PTR(-EINVAL);
224
225    client = kzalloc(sizeof(struct s3c_adc_client), GFP_KERNEL);
226    if (!client) {
227        dev_err(&pdev->dev, "no memory for adc client\n");
228        return ERR_PTR(-ENOMEM);
229    }
230
231    client->pdev = pdev;
232    client->is_ts = is_ts;
233    client->select_cb = select;
234    client->convert_cb = conv;
235
236    return client;
237}
238EXPORT_SYMBOL_GPL(s3c_adc_register);
239
240void s3c_adc_release(struct s3c_adc_client *client)
241{
242    unsigned long flags;
243
244    spin_lock_irqsave(&adc_dev->lock, flags);
245
246    /* We should really check that nothing is in progress. */
247    if (adc_dev->cur == client)
248        adc_dev->cur = NULL;
249    if (adc_dev->ts_pend == client)
250        adc_dev->ts_pend = NULL;
251    else {
252        struct list_head *p, *n;
253        struct s3c_adc_client *tmp;
254
255        list_for_each_safe(p, n, &adc_pending) {
256            tmp = list_entry(p, struct s3c_adc_client, pend);
257            if (tmp == client)
258                list_del(&tmp->pend);
259        }
260    }
261
262    if (adc_dev->cur == NULL)
263        s3c_adc_try(adc_dev);
264
265    spin_unlock_irqrestore(&adc_dev->lock, flags);
266    kfree(client);
267}
268EXPORT_SYMBOL_GPL(s3c_adc_release);
269
270static irqreturn_t s3c_adc_irq(int irq, void *pw)
271{
272    struct adc_device *adc = pw;
273    struct s3c_adc_client *client = adc->cur;
274    enum s3c_cpu_type cpu = platform_get_device_id(adc->pdev)->driver_data;
275    unsigned data0, data1;
276
277    if (!client) {
278        dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__);
279        goto exit;
280    }
281
282    data0 = readl(adc->regs + S3C2410_ADCDAT0);
283    data1 = readl(adc->regs + S3C2410_ADCDAT1);
284    adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1);
285
286    client->nr_samples--;
287
288    if (cpu == TYPE_S3C64XX) {
289        /* S3C64XX ADC resolution is 12-bit */
290        data0 &= 0xfff;
291        data1 &= 0xfff;
292    } else {
293        data0 &= 0x3ff;
294        data1 &= 0x3ff;
295    }
296
297    if (client->convert_cb)
298        (client->convert_cb)(client, data0, data1, &client->nr_samples);
299
300    if (client->nr_samples > 0) {
301        /* fire another conversion for this */
302
303        client->select_cb(client, 1);
304        s3c_adc_convert(adc);
305    } else {
306        spin_lock(&adc->lock);
307        (client->select_cb)(client, 0);
308        adc->cur = NULL;
309
310        s3c_adc_try(adc);
311        spin_unlock(&adc->lock);
312    }
313
314exit:
315    if (cpu == TYPE_S3C64XX) {
316        /* Clear ADC interrupt */
317        writel(0, adc->regs + S3C64XX_ADCCLRINT);
318    }
319    return IRQ_HANDLED;
320}
321
322static int s3c_adc_probe(struct platform_device *pdev)
323{
324    struct device *dev = &pdev->dev;
325    struct adc_device *adc;
326    struct resource *regs;
327    int ret;
328    unsigned tmp;
329
330    adc = kzalloc(sizeof(struct adc_device), GFP_KERNEL);
331    if (adc == NULL) {
332        dev_err(dev, "failed to allocate adc_device\n");
333        return -ENOMEM;
334    }
335
336    spin_lock_init(&adc->lock);
337
338    adc->pdev = pdev;
339    adc->prescale = S3C2410_ADCCON_PRSCVL(49);
340
341    adc->irq = platform_get_irq(pdev, 1);
342    if (adc->irq <= 0) {
343        dev_err(dev, "failed to get adc irq\n");
344        ret = -ENOENT;
345        goto err_alloc;
346    }
347
348    ret = request_irq(adc->irq, s3c_adc_irq, 0, dev_name(dev), adc);
349    if (ret < 0) {
350        dev_err(dev, "failed to attach adc irq\n");
351        goto err_alloc;
352    }
353
354    adc->clk = clk_get(dev, "adc");
355    if (IS_ERR(adc->clk)) {
356        dev_err(dev, "failed to get adc clock\n");
357        ret = PTR_ERR(adc->clk);
358        goto err_irq;
359    }
360
361    regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
362    if (!regs) {
363        dev_err(dev, "failed to find registers\n");
364        ret = -ENXIO;
365        goto err_clk;
366    }
367
368    adc->regs = ioremap(regs->start, resource_size(regs));
369    if (!adc->regs) {
370        dev_err(dev, "failed to map registers\n");
371        ret = -ENXIO;
372        goto err_clk;
373    }
374
375    clk_enable(adc->clk);
376
377    tmp = adc->prescale | S3C2410_ADCCON_PRSCEN;
378    if (platform_get_device_id(pdev)->driver_data == TYPE_S3C64XX) {
379        /* Enable 12-bit ADC resolution */
380        tmp |= S3C64XX_ADCCON_RESSEL;
381    }
382    writel(tmp, adc->regs + S3C2410_ADCCON);
383
384    dev_info(dev, "attached adc driver\n");
385
386    platform_set_drvdata(pdev, adc);
387    adc_dev = adc;
388
389    return 0;
390
391 err_clk:
392    clk_put(adc->clk);
393
394 err_irq:
395    free_irq(adc->irq, adc);
396
397 err_alloc:
398    kfree(adc);
399    return ret;
400}
401
402static int __devexit s3c_adc_remove(struct platform_device *pdev)
403{
404    struct adc_device *adc = platform_get_drvdata(pdev);
405
406    iounmap(adc->regs);
407    free_irq(adc->irq, adc);
408    clk_disable(adc->clk);
409    clk_put(adc->clk);
410    kfree(adc);
411
412    return 0;
413}
414
415#ifdef CONFIG_PM
416static int s3c_adc_suspend(struct platform_device *pdev, pm_message_t state)
417{
418    struct adc_device *adc = platform_get_drvdata(pdev);
419    unsigned long flags;
420    u32 con;
421
422    spin_lock_irqsave(&adc->lock, flags);
423
424    con = readl(adc->regs + S3C2410_ADCCON);
425    con |= S3C2410_ADCCON_STDBM;
426    writel(con, adc->regs + S3C2410_ADCCON);
427
428    disable_irq(adc->irq);
429    spin_unlock_irqrestore(&adc->lock, flags);
430    clk_disable(adc->clk);
431
432    return 0;
433}
434
435static int s3c_adc_resume(struct platform_device *pdev)
436{
437    struct adc_device *adc = platform_get_drvdata(pdev);
438
439    clk_enable(adc->clk);
440    enable_irq(adc->irq);
441
442    writel(adc->prescale | S3C2410_ADCCON_PRSCEN,
443           adc->regs + S3C2410_ADCCON);
444
445    return 0;
446}
447
448#else
449#define s3c_adc_suspend NULL
450#define s3c_adc_resume NULL
451#endif
452
453static struct platform_device_id s3c_adc_driver_ids[] = {
454    {
455        .name = "s3c24xx-adc",
456        .driver_data = TYPE_S3C24XX,
457    }, {
458        .name = "s3c64xx-adc",
459        .driver_data = TYPE_S3C64XX,
460    },
461    { }
462};
463MODULE_DEVICE_TABLE(platform, s3c_adc_driver_ids);
464
465static struct platform_driver s3c_adc_driver = {
466    .id_table = s3c_adc_driver_ids,
467    .driver = {
468        .name = "s3c-adc",
469        .owner = THIS_MODULE,
470    },
471    .probe = s3c_adc_probe,
472    .remove = __devexit_p(s3c_adc_remove),
473    .suspend = s3c_adc_suspend,
474    .resume = s3c_adc_resume,
475};
476
477static int __init adc_init(void)
478{
479    int ret;
480
481    ret = platform_driver_register(&s3c_adc_driver);
482    if (ret)
483        printk(KERN_ERR "%s: failed to add adc driver\n", __func__);
484
485    return ret;
486}
487
488arch_initcall(adc_init);
489

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