adc.c

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/* arch/arm/plat-samsung/adc.c
 *
 * Copyright (c) 2008 Simtec Electronics
 *  http://armlinux.simtec.co.uk/
 *  Ben Dooks <[email protected]>, <[email protected]>
 *
 * Samsung 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/sched.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/regulator/consumer.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.
 */

enum s3c_cpu_type {
    TYPE_ADCV1, /* S3C24XX */
    TYPE_ADCV11, /* S3C2443 */
    TYPE_ADCV12, /* S3C2416, S3C2450 */
    TYPE_ADCV2, /* S3C64XX, S5P64X0, S5PC100 */
    TYPE_ADCV3, /* S5PV210, S5PC110, EXYNOS4210 */
};

struct s3c_adc_client {
    struct platform_device  *pdev;
    struct list_head     pend;
    wait_queue_head_t   *wait;

    unsigned int         nr_samples;
    int          result;
    unsigned char        is_ts;
    unsigned char        channel;

    void    (*select_cb)(struct s3c_adc_client *c, unsigned selected);
    void    (*convert_cb)(struct s3c_adc_client *c,
                  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;
    spinlock_t       lock;

    unsigned int         prescale;

    int          irq;
    struct regulator    *vdd;
};

static struct adc_device *adc_dev;

static LIST_HEAD(adc_pending);  /* protected by adc_device.lock */

#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);
    enum s3c_cpu_type cpu = platform_get_device_id(adc->pdev)->driver_data;

    client->select_cb(client, 1);

    if (cpu == TYPE_ADCV1 || cpu == TYPE_ADCV2)
        con &= ~S3C2410_ADCCON_MUXMASK;
    con &= ~S3C2410_ADCCON_STDBM;
    con &= ~S3C2410_ADCCON_STARTMASK;

    if (!client->is_ts) {
        if (cpu == TYPE_ADCV3)
            writel(client->channel & 0xf, adc->regs + S5P_ADCMUX);
        else if (cpu == TYPE_ADCV11 || cpu == TYPE_ADCV12)
            writel(client->channel & 0xf,
                        adc->regs + S3C2443_ADCMUX);
        else
            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;
    }

    spin_lock_irqsave(&adc->lock, flags);

    if (client->is_ts && adc->ts_pend) {
        spin_unlock_irqrestore(&adc->lock, flags);
        return -EAGAIN;
    }

    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);

    spin_unlock_irqrestore(&adc->lock, flags);

    return 0;
}
EXPORT_SYMBOL_GPL(s3c_adc_start);

static void s3c_convert_done(struct s3c_adc_client *client,
                 unsigned v, unsigned u, unsigned *left)
{
    client->result = v;
    wake_up(client->wait);
}

int s3c_adc_read(struct s3c_adc_client *client, unsigned int ch)
{
    DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
    int ret;

    client->convert_cb = s3c_convert_done;
    client->wait = &wake;
    client->result = -1;

    ret = s3c_adc_start(client, ch, 1);
    if (ret < 0)
        goto err;

    ret = wait_event_timeout(wake, client->result >= 0, HZ / 2);
    if (client->result < 0) {
        ret = -ETIMEDOUT;
        goto err;
    }

    client->convert_cb = NULL;
    return client->result;

err:
    return ret;
}
EXPORT_SYMBOL_GPL(s3c_adc_read);

static void s3c_adc_default_select(struct s3c_adc_client *client,
                   unsigned select)
{
}

struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev,
                    void (*select)(struct s3c_adc_client *client,
                               unsigned int selected),
                    void (*conv)(struct s3c_adc_client *client,
                             unsigned d0, unsigned d1,
                             unsigned *samples_left),
                    unsigned int is_ts)
{
    struct s3c_adc_client *client;

    WARN_ON(!pdev);

    if (!select)
        select = s3c_adc_default_select;

    if (!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)
{
    unsigned long flags;

    spin_lock_irqsave(&adc_dev->lock, flags);

    /* 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);

    spin_unlock_irqrestore(&adc_dev->lock, flags);
    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;
    enum s3c_cpu_type cpu = platform_get_device_id(adc->pdev)->driver_data;
    unsigned data0, data1;

    if (!client) {
        dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__);
        goto exit;
    }

    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--;

    if (cpu == TYPE_ADCV1 || cpu == TYPE_ADCV11) {
        data0 &= 0x3ff;
        data1 &= 0x3ff;
    } else {
        /* S3C2416/S3C64XX/S5P ADC resolution is 12-bit */
        data0 &= 0xfff;
        data1 &= 0xfff;
    }

    if (client->convert_cb)
        (client->convert_cb)(client, data0, data1, &client->nr_samples);

    if (client->nr_samples > 0) {
        /* fire another conversion for this */

        client->select_cb(client, 1);
        s3c_adc_convert(adc);
    } else {
        spin_lock(&adc->lock);
        (client->select_cb)(client, 0);
        adc->cur = NULL;

        s3c_adc_try(adc);
        spin_unlock(&adc->lock);
    }

exit:
    if (cpu == TYPE_ADCV2 || cpu == TYPE_ADCV3) {
        /* Clear ADC interrupt */
        writel(0, adc->regs + S3C64XX_ADCCLRINT);
    }
    return IRQ_HANDLED;
}

static int s3c_adc_probe(struct platform_device *pdev)
{
    struct device *dev = &pdev->dev;
    struct adc_device *adc;
    struct resource *regs;
    enum s3c_cpu_type cpu = platform_get_device_id(pdev)->driver_data;
    int ret;
    unsigned tmp;

    adc = kzalloc(sizeof(struct adc_device), GFP_KERNEL);
    if (adc == NULL) {
        dev_err(dev, "failed to allocate adc_device\n");
        return -ENOMEM;
    }

    spin_lock_init(&adc->lock);

    adc->pdev = pdev;
    adc->prescale = S3C2410_ADCCON_PRSCVL(49);

    adc->vdd = regulator_get(dev, "vdd");
    if (IS_ERR(adc->vdd)) {
        dev_err(dev, "operating without regulator \"vdd\" .\n");
        ret = PTR_ERR(adc->vdd);
        goto err_alloc;
    }

    adc->irq = platform_get_irq(pdev, 1);
    if (adc->irq <= 0) {
        dev_err(dev, "failed to get adc irq\n");
        ret = -ENOENT;
        goto err_reg;
    }

    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_reg;
    }

    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;
    }

    ret = regulator_enable(adc->vdd);
    if (ret)
        goto err_ioremap;

    clk_enable(adc->clk);

    tmp = adc->prescale | S3C2410_ADCCON_PRSCEN;

    /* Enable 12-bit ADC resolution */
    if (cpu == TYPE_ADCV12)
        tmp |= S3C2416_ADCCON_RESSEL;
    if (cpu == TYPE_ADCV2 || cpu == TYPE_ADCV3)
        tmp |= S3C64XX_ADCCON_RESSEL;

    writel(tmp, adc->regs + S3C2410_ADCCON);

    dev_info(dev, "attached adc driver\n");

    platform_set_drvdata(pdev, adc);
    adc_dev = adc;

    return 0;

 err_ioremap:
    iounmap(adc->regs);
 err_clk:
    clk_put(adc->clk);

 err_irq:
    free_irq(adc->irq, adc);
 err_reg:
    regulator_put(adc->vdd);
 err_alloc:
    kfree(adc);
    return ret;
}

static int __devexit 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);
    regulator_disable(adc->vdd);
    regulator_put(adc->vdd);
    clk_put(adc->clk);
    kfree(adc);

    return 0;
}

#ifdef CONFIG_PM
static int s3c_adc_suspend(struct device *dev)
{
    struct platform_device *pdev = container_of(dev,
            struct platform_device, dev);
    struct adc_device *adc = platform_get_drvdata(pdev);
    unsigned long flags;
    u32 con;

    spin_lock_irqsave(&adc->lock, flags);

    con = readl(adc->regs + S3C2410_ADCCON);
    con |= S3C2410_ADCCON_STDBM;
    writel(con, adc->regs + S3C2410_ADCCON);

    disable_irq(adc->irq);
    spin_unlock_irqrestore(&adc->lock, flags);
    clk_disable(adc->clk);
    regulator_disable(adc->vdd);

    return 0;
}

static int s3c_adc_resume(struct device *dev)
{
    struct platform_device *pdev = container_of(dev,
            struct platform_device, dev);
    struct adc_device *adc = platform_get_drvdata(pdev);
    enum s3c_cpu_type cpu = platform_get_device_id(pdev)->driver_data;
    int ret;
    unsigned long tmp;

    ret = regulator_enable(adc->vdd);
    if (ret)
        return ret;
    clk_enable(adc->clk);
    enable_irq(adc->irq);

    tmp = adc->prescale | S3C2410_ADCCON_PRSCEN;

    /* Enable 12-bit ADC resolution */
    if (cpu == TYPE_ADCV12)
        tmp |= S3C2416_ADCCON_RESSEL;
    if (cpu == TYPE_ADCV2 || cpu == TYPE_ADCV3)
        tmp |= S3C64XX_ADCCON_RESSEL;

    writel(tmp, adc->regs + S3C2410_ADCCON);

    return 0;
}

#else
#define s3c_adc_suspend NULL
#define s3c_adc_resume NULL
#endif

static struct platform_device_id s3c_adc_driver_ids[] = {
    {
        .name           = "s3c24xx-adc",
        .driver_data    = TYPE_ADCV1,
    }, {
        .name       = "s3c2443-adc",
        .driver_data    = TYPE_ADCV11,
    }, {
        .name       = "s3c2416-adc",
        .driver_data    = TYPE_ADCV12,
    }, {
        .name           = "s3c64xx-adc",
        .driver_data    = TYPE_ADCV2,
    }, {
        .name       = "samsung-adc-v3",
        .driver_data    = TYPE_ADCV3,
    },
    { }
};
MODULE_DEVICE_TABLE(platform, s3c_adc_driver_ids);

static const struct dev_pm_ops adc_pm_ops = {
    .suspend    = s3c_adc_suspend,
    .resume     = s3c_adc_resume,
};

static struct platform_driver s3c_adc_driver = {
    .id_table   = s3c_adc_driver_ids,
    .driver     = {
        .name   = "s3c-adc",
        .owner  = THIS_MODULE,
        .pm = &adc_pm_ops,
    },
    .probe      = s3c_adc_probe,
    .remove     = __devexit_p(s3c_adc_remove),
};

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;
}

module_init(adc_init);