1 /* arch/arm/plat-samsung/adc.c
3 * Copyright (c) 2008 Simtec Electronics
4 * http://armlinux.simtec.co.uk/
5 * Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
7 * Samsung ADC device core
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.
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/err.h>
20 #include <linux/clk.h>
21 #include <linux/interrupt.h>
24 #include <plat/regs-adc.h>
27 /* This driver is designed to control the usage of the ADC block between
28 * the touchscreen and any other drivers that may need to use it, such as
31 * Priority will be given to the touchscreen driver, but as this itself is
32 * rate limited it should not starve other requests which are processed in
33 * order that they are received.
35 * Each user registers to get a client block which uniquely identifies it
36 * and stores information such as the necessary functions to callback when
45 struct s3c_adc_client {
46 struct platform_device *pdev;
47 struct list_head pend;
48 wait_queue_head_t *wait;
50 unsigned int nr_samples;
53 unsigned char channel;
55 void (*select_cb)(struct s3c_adc_client *c, unsigned selected);
56 void (*convert_cb)(struct s3c_adc_client *c,
57 unsigned val1, unsigned val2,
58 unsigned *samples_left);
62 struct platform_device *pdev;
63 struct platform_device *owner;
65 struct s3c_adc_client *cur;
66 struct s3c_adc_client *ts_pend;
69 unsigned int prescale;
74 static struct adc_device *adc_dev;
76 static LIST_HEAD(adc_pending);
78 #define adc_dbg(_adc, msg...) dev_dbg(&(_adc)->pdev->dev, msg)
80 static inline void s3c_adc_convert(struct adc_device *adc)
82 unsigned con = readl(adc->regs + S3C2410_ADCCON);
84 con |= S3C2410_ADCCON_ENABLE_START;
85 writel(con, adc->regs + S3C2410_ADCCON);
88 static inline void s3c_adc_select(struct adc_device *adc,
89 struct s3c_adc_client *client)
91 unsigned con = readl(adc->regs + S3C2410_ADCCON);
93 client->select_cb(client, 1);
95 con &= ~S3C2410_ADCCON_MUXMASK;
96 con &= ~S3C2410_ADCCON_STDBM;
97 con &= ~S3C2410_ADCCON_STARTMASK;
100 con |= S3C2410_ADCCON_SELMUX(client->channel);
102 writel(con, adc->regs + S3C2410_ADCCON);
105 static void s3c_adc_dbgshow(struct adc_device *adc)
107 adc_dbg(adc, "CON=%08x, TSC=%08x, DLY=%08x\n",
108 readl(adc->regs + S3C2410_ADCCON),
109 readl(adc->regs + S3C2410_ADCTSC),
110 readl(adc->regs + S3C2410_ADCDLY));
113 static void s3c_adc_try(struct adc_device *adc)
115 struct s3c_adc_client *next = adc->ts_pend;
117 if (!next && !list_empty(&adc_pending)) {
118 next = list_first_entry(&adc_pending,
119 struct s3c_adc_client, pend);
120 list_del(&next->pend);
125 adc_dbg(adc, "new client is %p\n", next);
127 s3c_adc_select(adc, next);
128 s3c_adc_convert(adc);
129 s3c_adc_dbgshow(adc);
133 int s3c_adc_start(struct s3c_adc_client *client,
134 unsigned int channel, unsigned int nr_samples)
136 struct adc_device *adc = adc_dev;
140 printk(KERN_ERR "%s: failed to find adc\n", __func__);
144 if (client->is_ts && adc->ts_pend)
147 local_irq_save(flags);
149 client->channel = channel;
150 client->nr_samples = nr_samples;
153 adc->ts_pend = client;
155 list_add_tail(&client->pend, &adc_pending);
159 local_irq_restore(flags);
163 EXPORT_SYMBOL_GPL(s3c_adc_start);
165 static void s3c_convert_done(struct s3c_adc_client *client,
166 unsigned v, unsigned u, unsigned *left)
169 wake_up(client->wait);
172 int s3c_adc_read(struct s3c_adc_client *client, unsigned int ch)
174 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
177 client->convert_cb = s3c_convert_done;
178 client->wait = &wake;
181 ret = s3c_adc_start(client, ch, 1);
185 ret = wait_event_timeout(wake, client->result >= 0, HZ / 2);
186 if (client->result < 0) {
191 client->convert_cb = NULL;
192 return client->result;
197 EXPORT_SYMBOL_GPL(s3c_adc_read);
199 static void s3c_adc_default_select(struct s3c_adc_client *client,
204 struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev,
205 void (*select)(struct s3c_adc_client *client,
206 unsigned int selected),
207 void (*conv)(struct s3c_adc_client *client,
208 unsigned d0, unsigned d1,
209 unsigned *samples_left),
212 struct s3c_adc_client *client;
217 select = s3c_adc_default_select;
220 return ERR_PTR(-EINVAL);
222 client = kzalloc(sizeof(struct s3c_adc_client), GFP_KERNEL);
224 dev_err(&pdev->dev, "no memory for adc client\n");
225 return ERR_PTR(-ENOMEM);
229 client->is_ts = is_ts;
230 client->select_cb = select;
231 client->convert_cb = conv;
235 EXPORT_SYMBOL_GPL(s3c_adc_register);
237 void s3c_adc_release(struct s3c_adc_client *client)
239 /* We should really check that nothing is in progress. */
240 if (adc_dev->cur == client)
242 if (adc_dev->ts_pend == client)
243 adc_dev->ts_pend = NULL;
245 struct list_head *p, *n;
246 struct s3c_adc_client *tmp;
248 list_for_each_safe(p, n, &adc_pending) {
249 tmp = list_entry(p, struct s3c_adc_client, pend);
251 list_del(&tmp->pend);
255 if (adc_dev->cur == NULL)
256 s3c_adc_try(adc_dev);
259 EXPORT_SYMBOL_GPL(s3c_adc_release);
261 static irqreturn_t s3c_adc_irq(int irq, void *pw)
263 struct adc_device *adc = pw;
264 struct s3c_adc_client *client = adc->cur;
265 enum s3c_cpu_type cpu = platform_get_device_id(adc->pdev)->driver_data;
267 unsigned data0, data1;
270 dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__);
274 data0 = readl(adc->regs + S3C2410_ADCDAT0);
275 data1 = readl(adc->regs + S3C2410_ADCDAT1);
276 adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1);
278 client->nr_samples--;
280 if (cpu == TYPE_S3C64XX) {
281 /* S3C64XX ADC resolution is 12-bit */
289 if (client->convert_cb)
290 (client->convert_cb)(client, data0, data1, &client->nr_samples);
292 if (client->nr_samples > 0) {
293 /* fire another conversion for this */
295 client->select_cb(client, 1);
296 s3c_adc_convert(adc);
298 local_irq_save(flags);
299 (client->select_cb)(client, 0);
303 local_irq_restore(flags);
307 if (cpu == TYPE_S3C64XX) {
308 /* Clear ADC interrupt */
309 writel(0, adc->regs + S3C64XX_ADCCLRINT);
314 static int s3c_adc_probe(struct platform_device *pdev)
316 struct device *dev = &pdev->dev;
317 struct adc_device *adc;
318 struct resource *regs;
322 adc = kzalloc(sizeof(struct adc_device), GFP_KERNEL);
324 dev_err(dev, "failed to allocate adc_device\n");
329 adc->prescale = S3C2410_ADCCON_PRSCVL(49);
331 adc->irq = platform_get_irq(pdev, 1);
333 dev_err(dev, "failed to get adc irq\n");
338 ret = request_irq(adc->irq, s3c_adc_irq, 0, dev_name(dev), adc);
340 dev_err(dev, "failed to attach adc irq\n");
344 adc->clk = clk_get(dev, "adc");
345 if (IS_ERR(adc->clk)) {
346 dev_err(dev, "failed to get adc clock\n");
347 ret = PTR_ERR(adc->clk);
351 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
353 dev_err(dev, "failed to find registers\n");
358 adc->regs = ioremap(regs->start, resource_size(regs));
360 dev_err(dev, "failed to map registers\n");
365 clk_enable(adc->clk);
367 tmp = adc->prescale | S3C2410_ADCCON_PRSCEN;
368 if (platform_get_device_id(pdev)->driver_data == TYPE_S3C64XX) {
369 /* Enable 12-bit ADC resolution */
370 tmp |= S3C64XX_ADCCON_RESSEL;
372 writel(tmp, adc->regs + S3C2410_ADCCON);
374 dev_info(dev, "attached adc driver\n");
376 platform_set_drvdata(pdev, adc);
385 free_irq(adc->irq, adc);
392 static int __devexit s3c_adc_remove(struct platform_device *pdev)
394 struct adc_device *adc = platform_get_drvdata(pdev);
397 free_irq(adc->irq, adc);
398 clk_disable(adc->clk);
406 static int s3c_adc_suspend(struct platform_device *pdev, pm_message_t state)
408 struct adc_device *adc = platform_get_drvdata(pdev);
411 con = readl(adc->regs + S3C2410_ADCCON);
412 con |= S3C2410_ADCCON_STDBM;
413 writel(con, adc->regs + S3C2410_ADCCON);
415 disable_irq(adc->irq);
416 clk_disable(adc->clk);
421 static int s3c_adc_resume(struct platform_device *pdev)
423 struct adc_device *adc = platform_get_drvdata(pdev);
425 clk_enable(adc->clk);
426 enable_irq(adc->irq);
428 writel(adc->prescale | S3C2410_ADCCON_PRSCEN,
429 adc->regs + S3C2410_ADCCON);
435 #define s3c_adc_suspend NULL
436 #define s3c_adc_resume NULL
439 static struct platform_device_id s3c_adc_driver_ids[] = {
441 .name = "s3c24xx-adc",
442 .driver_data = TYPE_S3C24XX,
444 .name = "s3c64xx-adc",
445 .driver_data = TYPE_S3C64XX,
449 MODULE_DEVICE_TABLE(platform, s3c_adc_driver_ids);
451 static struct platform_driver s3c_adc_driver = {
452 .id_table = s3c_adc_driver_ids,
455 .owner = THIS_MODULE,
457 .probe = s3c_adc_probe,
458 .remove = __devexit_p(s3c_adc_remove),
459 .suspend = s3c_adc_suspend,
460 .resume = s3c_adc_resume,
463 static int __init adc_init(void)
467 ret = platform_driver_register(&s3c_adc_driver);
469 printk(KERN_ERR "%s: failed to add adc driver\n", __func__);
474 arch_initcall(adc_init);