/* 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);
};
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));
}
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 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. */
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->convert_cb)(data0 & 0x3ff, data1 & 0x3ff);
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);
