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