kernel-ark/arch/arm/plat-s3c24xx/adc.c
Nelson Castillo 3f7ea467be [ARM] S3C: ADC: Expose number of remaining conversions to
convert callback

This patch allow us to efficiently modify the number of
remaining conversions from the client side. This us useful
when we do not know in advance how many conversions we will
need or when we need to cancel pending conversions.

This change is simple enough to be compatible with existing
code that can just define the new pointer in the callback
and ignore it.

Sample usage:

http://tinyurl.com/s3c2410-ts-c (function stylus_adc_action).

Signed-off-by: Nelson Castillo <arhuaco@freaks-unidos.net>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-05-16 22:22:01 +01:00

393 lines
8.4 KiB
C

/* arch/arm/plat-s3c24xx/adc.c
*
* Copyright (c) 2008 Simtec Electronics
* http://armlinux.simtec.co.uk/
* Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
*
* S3C24XX ADC device core
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/list.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <plat/regs-adc.h>
#include <plat/adc.h>
/* This driver is designed to control the usage of the ADC block between
* the touchscreen and any other drivers that may need to use it, such as
* the hwmon driver.
*
* Priority will be given to the touchscreen driver, but as this itself is
* rate limited it should not starve other requests which are processed in
* order that they are received.
*
* Each user registers to get a client block which uniquely identifies it
* and stores information such as the necessary functions to callback when
* action is required.
*/
struct s3c_adc_client {
struct platform_device *pdev;
struct list_head pend;
unsigned int nr_samples;
unsigned char is_ts;
unsigned char channel;
void (*select_cb)(unsigned selected);
void (*convert_cb)(unsigned val1, unsigned val2,
unsigned *samples_left);
};
struct adc_device {
struct platform_device *pdev;
struct platform_device *owner;
struct clk *clk;
struct s3c_adc_client *cur;
struct s3c_adc_client *ts_pend;
void __iomem *regs;
unsigned int prescale;
int irq;
};
static struct adc_device *adc_dev;
static LIST_HEAD(adc_pending);
#define adc_dbg(_adc, msg...) dev_dbg(&(_adc)->pdev->dev, msg)
static inline void s3c_adc_convert(struct adc_device *adc)
{
unsigned con = readl(adc->regs + S3C2410_ADCCON);
con |= S3C2410_ADCCON_ENABLE_START;
writel(con, adc->regs + S3C2410_ADCCON);
}
static inline void s3c_adc_select(struct adc_device *adc,
struct s3c_adc_client *client)
{
unsigned con = readl(adc->regs + S3C2410_ADCCON);
client->select_cb(1);
con &= ~S3C2410_ADCCON_MUXMASK;
con &= ~S3C2410_ADCCON_STDBM;
con &= ~S3C2410_ADCCON_STARTMASK;
if (!client->is_ts)
con |= S3C2410_ADCCON_SELMUX(client->channel);
writel(con, adc->regs + S3C2410_ADCCON);
}
static void s3c_adc_dbgshow(struct adc_device *adc)
{
adc_dbg(adc, "CON=%08x, TSC=%08x, DLY=%08x\n",
readl(adc->regs + S3C2410_ADCCON),
readl(adc->regs + S3C2410_ADCTSC),
readl(adc->regs + S3C2410_ADCDLY));
}
static void s3c_adc_try(struct adc_device *adc)
{
struct s3c_adc_client *next = adc->ts_pend;
if (!next && !list_empty(&adc_pending)) {
next = list_first_entry(&adc_pending,
struct s3c_adc_client, pend);
list_del(&next->pend);
} else
adc->ts_pend = NULL;
if (next) {
adc_dbg(adc, "new client is %p\n", next);
adc->cur = next;
s3c_adc_select(adc, next);
s3c_adc_convert(adc);
s3c_adc_dbgshow(adc);
}
}
int s3c_adc_start(struct s3c_adc_client *client,
unsigned int channel, unsigned int nr_samples)
{
struct adc_device *adc = adc_dev;
unsigned long flags;
if (!adc) {
printk(KERN_ERR "%s: failed to find adc\n", __func__);
return -EINVAL;
}
if (client->is_ts && adc->ts_pend)
return -EAGAIN;
local_irq_save(flags);
client->channel = channel;
client->nr_samples = nr_samples;
if (client->is_ts)
adc->ts_pend = client;
else
list_add_tail(&client->pend, &adc_pending);
if (!adc->cur)
s3c_adc_try(adc);
local_irq_restore(flags);
return 0;
}
EXPORT_SYMBOL_GPL(s3c_adc_start);
static void s3c_adc_default_select(unsigned select)
{
}
struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev,
void (*select)(unsigned int selected),
void (*conv)(unsigned d0, unsigned d1,
unsigned *samples_left),
unsigned int is_ts)
{
struct s3c_adc_client *client;
WARN_ON(!pdev);
WARN_ON(!conv);
if (!select)
select = s3c_adc_default_select;
if (!conv || !pdev)
return ERR_PTR(-EINVAL);
client = kzalloc(sizeof(struct s3c_adc_client), GFP_KERNEL);
if (!client) {
dev_err(&pdev->dev, "no memory for adc client\n");
return ERR_PTR(-ENOMEM);
}
client->pdev = pdev;
client->is_ts = is_ts;
client->select_cb = select;
client->convert_cb = conv;
return client;
}
EXPORT_SYMBOL_GPL(s3c_adc_register);
void s3c_adc_release(struct s3c_adc_client *client)
{
/* We should really check that nothing is in progress. */
if (adc_dev->cur == client)
adc_dev->cur = NULL;
if (adc_dev->ts_pend == client)
adc_dev->ts_pend = NULL;
else {
struct list_head *p, *n;
struct s3c_adc_client *tmp;
list_for_each_safe(p, n, &adc_pending) {
tmp = list_entry(p, struct s3c_adc_client, pend);
if (tmp == client)
list_del(&tmp->pend);
}
}
if (adc_dev->cur == NULL)
s3c_adc_try(adc_dev);
kfree(client);
}
EXPORT_SYMBOL_GPL(s3c_adc_release);
static irqreturn_t s3c_adc_irq(int irq, void *pw)
{
struct adc_device *adc = pw;
struct s3c_adc_client *client = adc->cur;
unsigned long flags;
unsigned data0, data1;
if (!client) {
dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__);
return IRQ_HANDLED;
}
data0 = readl(adc->regs + S3C2410_ADCDAT0);
data1 = readl(adc->regs + S3C2410_ADCDAT1);
adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1);
client->nr_samples--;
(client->convert_cb)(data0 & 0x3ff, data1 & 0x3ff, &client->nr_samples);
if (client->nr_samples > 0) {
/* fire another conversion for this */
client->select_cb(1);
s3c_adc_convert(adc);
} else {
local_irq_save(flags);
(client->select_cb)(0);
adc->cur = NULL;
s3c_adc_try(adc);
local_irq_restore(flags);
}
return IRQ_HANDLED;
}
static int s3c_adc_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct adc_device *adc;
struct resource *regs;
int ret;
adc = kzalloc(sizeof(struct adc_device), GFP_KERNEL);
if (adc == NULL) {
dev_err(dev, "failed to allocate adc_device\n");
return -ENOMEM;
}
adc->pdev = pdev;
adc->prescale = S3C2410_ADCCON_PRSCVL(49);
adc->irq = platform_get_irq(pdev, 1);
if (adc->irq <= 0) {
dev_err(dev, "failed to get adc irq\n");
ret = -ENOENT;
goto err_alloc;
}
ret = request_irq(adc->irq, s3c_adc_irq, 0, dev_name(dev), adc);
if (ret < 0) {
dev_err(dev, "failed to attach adc irq\n");
goto err_alloc;
}
adc->clk = clk_get(dev, "adc");
if (IS_ERR(adc->clk)) {
dev_err(dev, "failed to get adc clock\n");
ret = PTR_ERR(adc->clk);
goto err_irq;
}
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!regs) {
dev_err(dev, "failed to find registers\n");
ret = -ENXIO;
goto err_clk;
}
adc->regs = ioremap(regs->start, resource_size(regs));
if (!adc->regs) {
dev_err(dev, "failed to map registers\n");
ret = -ENXIO;
goto err_clk;
}
clk_enable(adc->clk);
writel(adc->prescale | S3C2410_ADCCON_PRSCEN,
adc->regs + S3C2410_ADCCON);
dev_info(dev, "attached adc driver\n");
platform_set_drvdata(pdev, adc);
adc_dev = adc;
return 0;
err_clk:
clk_put(adc->clk);
err_irq:
free_irq(adc->irq, adc);
err_alloc:
kfree(adc);
return ret;
}
static int s3c_adc_remove(struct platform_device *pdev)
{
struct adc_device *adc = platform_get_drvdata(pdev);
iounmap(adc->regs);
free_irq(adc->irq, adc);
clk_disable(adc->clk);
clk_put(adc->clk);
kfree(adc);
return 0;
}
#ifdef CONFIG_PM
static int s3c_adc_suspend(struct platform_device *pdev, pm_message_t state)
{
struct adc_device *adc = platform_get_drvdata(pdev);
u32 con;
con = readl(adc->regs + S3C2410_ADCCON);
con |= S3C2410_ADCCON_STDBM;
writel(con, adc->regs + S3C2410_ADCCON);
clk_disable(adc->clk);
return 0;
}
static int s3c_adc_resume(struct platform_device *pdev)
{
struct adc_device *adc = platform_get_drvdata(pdev);
clk_enable(adc->clk);
writel(adc->prescale | S3C2410_ADCCON_PRSCEN,
adc->regs + S3C2410_ADCCON);
return 0;
}
#else
#define s3c_adc_suspend NULL
#define s3c_adc_resume NULL
#endif
static struct platform_driver s3c_adc_driver = {
.driver = {
.name = "s3c24xx-adc",
.owner = THIS_MODULE,
},
.probe = s3c_adc_probe,
.remove = __devexit_p(s3c_adc_remove),
.suspend = s3c_adc_suspend,
.resume = s3c_adc_resume,
};
static int __init adc_init(void)
{
int ret;
ret = platform_driver_register(&s3c_adc_driver);
if (ret)
printk(KERN_ERR "%s: failed to add adc driver\n", __func__);
return ret;
}
arch_initcall(adc_init);