gpio-adp5588.c

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/*
 * GPIO Chip driver for Analog Devices
 * ADP5588/ADP5587 I/O Expander and QWERTY Keypad Controller
 *
 * Copyright 2009-2010 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/irq.h>

#include <linux/i2c/adp5588.h>

#define DRV_NAME    "adp5588-gpio"

/*
 * Early pre 4.0 Silicon required to delay readout by at least 25ms,
 * since the Event Counter Register updated 25ms after the interrupt
 * asserted.
 */
#define WA_DELAYED_READOUT_REVID(rev)   ((rev) < 4)

struct adp5588_gpio {
    struct i2c_client *client;
    struct gpio_chip gpio_chip;
    struct mutex lock;  /* protect cached dir, dat_out */
    /* protect serialized access to the interrupt controller bus */
    struct mutex irq_lock;
    unsigned gpio_start;
    unsigned irq_base;
    uint8_t dat_out[3];
    uint8_t dir[3];
    uint8_t int_lvl[3];
    uint8_t int_en[3];
    uint8_t irq_mask[3];
    uint8_t irq_stat[3];
};

static int adp5588_gpio_read(struct i2c_client *client, u8 reg)
{
    int ret = i2c_smbus_read_byte_data(client, reg);

    if (ret < 0)
        dev_err(&client->dev, "Read Error\n");

    return ret;
}

static int adp5588_gpio_write(struct i2c_client *client, u8 reg, u8 val)
{
    int ret = i2c_smbus_write_byte_data(client, reg, val);

    if (ret < 0)
        dev_err(&client->dev, "Write Error\n");

    return ret;
}

static int adp5588_gpio_get_value(struct gpio_chip *chip, unsigned off)
{
    struct adp5588_gpio *dev =
        container_of(chip, struct adp5588_gpio, gpio_chip);

    return !!(adp5588_gpio_read(dev->client,
          GPIO_DAT_STAT1 + ADP5588_BANK(off)) & ADP5588_BIT(off));
}

static void adp5588_gpio_set_value(struct gpio_chip *chip,
                   unsigned off, int val)
{
    unsigned bank, bit;
    struct adp5588_gpio *dev =
        container_of(chip, struct adp5588_gpio, gpio_chip);

    bank = ADP5588_BANK(off);
    bit = ADP5588_BIT(off);

    mutex_lock(&dev->lock);
    if (val)
        dev->dat_out[bank] |= bit;
    else
        dev->dat_out[bank] &= ~bit;

    adp5588_gpio_write(dev->client, GPIO_DAT_OUT1 + bank,
               dev->dat_out[bank]);
    mutex_unlock(&dev->lock);
}

static int adp5588_gpio_direction_input(struct gpio_chip *chip, unsigned off)
{
    int ret;
    unsigned bank;
    struct adp5588_gpio *dev =
        container_of(chip, struct adp5588_gpio, gpio_chip);

    bank = ADP5588_BANK(off);

    mutex_lock(&dev->lock);
    dev->dir[bank] &= ~ADP5588_BIT(off);
    ret = adp5588_gpio_write(dev->client, GPIO_DIR1 + bank, dev->dir[bank]);
    mutex_unlock(&dev->lock);

    return ret;
}

static int adp5588_gpio_direction_output(struct gpio_chip *chip,
                     unsigned off, int val)
{
    int ret;
    unsigned bank, bit;
    struct adp5588_gpio *dev =
        container_of(chip, struct adp5588_gpio, gpio_chip);

    bank = ADP5588_BANK(off);
    bit = ADP5588_BIT(off);

    mutex_lock(&dev->lock);
    dev->dir[bank] |= bit;

    if (val)
        dev->dat_out[bank] |= bit;
    else
        dev->dat_out[bank] &= ~bit;

    ret = adp5588_gpio_write(dev->client, GPIO_DAT_OUT1 + bank,
                 dev->dat_out[bank]);
    ret |= adp5588_gpio_write(dev->client, GPIO_DIR1 + bank,
                 dev->dir[bank]);
    mutex_unlock(&dev->lock);

    return ret;
}

#ifdef CONFIG_GPIO_ADP5588_IRQ
static int adp5588_gpio_to_irq(struct gpio_chip *chip, unsigned off)
{
    struct adp5588_gpio *dev =
        container_of(chip, struct adp5588_gpio, gpio_chip);
    return dev->irq_base + off;
}

static void adp5588_irq_bus_lock(struct irq_data *d)
{
    struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);

    mutex_lock(&dev->irq_lock);
}

 /*
  * genirq core code can issue chip->mask/unmask from atomic context.
  * This doesn't work for slow busses where an access needs to sleep.
  * bus_sync_unlock() is therefore called outside the atomic context,
  * syncs the current irq mask state with the slow external controller
  * and unlocks the bus.
  */

static void adp5588_irq_bus_sync_unlock(struct irq_data *d)
{
    struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
    int i;

    for (i = 0; i <= ADP5588_BANK(ADP5588_MAXGPIO); i++)
        if (dev->int_en[i] ^ dev->irq_mask[i]) {
            dev->int_en[i] = dev->irq_mask[i];
            adp5588_gpio_write(dev->client, GPIO_INT_EN1 + i,
                       dev->int_en[i]);
        }

    mutex_unlock(&dev->irq_lock);
}

static void adp5588_irq_mask(struct irq_data *d)
{
    struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
    unsigned gpio = d->irq - dev->irq_base;

    dev->irq_mask[ADP5588_BANK(gpio)] &= ~ADP5588_BIT(gpio);
}

static void adp5588_irq_unmask(struct irq_data *d)
{
    struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
    unsigned gpio = d->irq - dev->irq_base;

    dev->irq_mask[ADP5588_BANK(gpio)] |= ADP5588_BIT(gpio);
}

static int adp5588_irq_set_type(struct irq_data *d, unsigned int type)
{
    struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
    uint16_t gpio = d->irq - dev->irq_base;
    unsigned bank, bit;

    if ((type & IRQ_TYPE_EDGE_BOTH)) {
        dev_err(&dev->client->dev, "irq %d: unsupported type %d\n",
            d->irq, type);
        return -EINVAL;
    }

    bank = ADP5588_BANK(gpio);
    bit = ADP5588_BIT(gpio);

    if (type & IRQ_TYPE_LEVEL_HIGH)
        dev->int_lvl[bank] |= bit;
    else if (type & IRQ_TYPE_LEVEL_LOW)
        dev->int_lvl[bank] &= ~bit;
    else
        return -EINVAL;

    adp5588_gpio_direction_input(&dev->gpio_chip, gpio);
    adp5588_gpio_write(dev->client, GPIO_INT_LVL1 + bank,
               dev->int_lvl[bank]);

    return 0;
}

static struct irq_chip adp5588_irq_chip = {
    .name           = "adp5588",
    .irq_mask       = adp5588_irq_mask,
    .irq_unmask     = adp5588_irq_unmask,
    .irq_bus_lock       = adp5588_irq_bus_lock,
    .irq_bus_sync_unlock    = adp5588_irq_bus_sync_unlock,
    .irq_set_type       = adp5588_irq_set_type,
};

static int adp5588_gpio_read_intstat(struct i2c_client *client, u8 *buf)
{
    int ret = i2c_smbus_read_i2c_block_data(client, GPIO_INT_STAT1, 3, buf);

    if (ret < 0)
        dev_err(&client->dev, "Read INT_STAT Error\n");

    return ret;
}

static irqreturn_t adp5588_irq_handler(int irq, void *devid)
{
    struct adp5588_gpio *dev = devid;
    unsigned status, bank, bit, pending;
    int ret;
    status = adp5588_gpio_read(dev->client, INT_STAT);

    if (status & ADP5588_GPI_INT) {
        ret = adp5588_gpio_read_intstat(dev->client, dev->irq_stat);
        if (ret < 0)
            memset(dev->irq_stat, 0, ARRAY_SIZE(dev->irq_stat));

        for (bank = 0, bit = 0; bank <= ADP5588_BANK(ADP5588_MAXGPIO);
            bank++, bit = 0) {
            pending = dev->irq_stat[bank] & dev->irq_mask[bank];

            while (pending) {
                if (pending & (1 << bit)) {
                    handle_nested_irq(dev->irq_base +
                              (bank << 3) + bit);
                    pending &= ~(1 << bit);

                }
                bit++;
            }
        }
    }

    adp5588_gpio_write(dev->client, INT_STAT, status); /* Status is W1C */

    return IRQ_HANDLED;
}

static int adp5588_irq_setup(struct adp5588_gpio *dev)
{
    struct i2c_client *client = dev->client;
    struct adp5588_gpio_platform_data *pdata = client->dev.platform_data;
    unsigned gpio;
    int ret;

    adp5588_gpio_write(client, CFG, ADP5588_AUTO_INC);
    adp5588_gpio_write(client, INT_STAT, -1); /* status is W1C */
    adp5588_gpio_read_intstat(client, dev->irq_stat); /* read to clear */

    dev->irq_base = pdata->irq_base;
    mutex_init(&dev->irq_lock);

    for (gpio = 0; gpio < dev->gpio_chip.ngpio; gpio++) {
        int irq = gpio + dev->irq_base;
        irq_set_chip_data(irq, dev);
        irq_set_chip_and_handler(irq, &adp5588_irq_chip,
                     handle_level_irq);
        irq_set_nested_thread(irq, 1);
#ifdef CONFIG_ARM
        /*
         * ARM needs us to explicitly flag the IRQ as VALID,
         * once we do so, it will also set the noprobe.
         */
        set_irq_flags(irq, IRQF_VALID);
#else
        irq_set_noprobe(irq);
#endif
    }

    ret = request_threaded_irq(client->irq,
                   NULL,
                   adp5588_irq_handler,
                   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
                   dev_name(&client->dev), dev);
    if (ret) {
        dev_err(&client->dev, "failed to request irq %d\n",
            client->irq);
        goto out;
    }

    dev->gpio_chip.to_irq = adp5588_gpio_to_irq;
    adp5588_gpio_write(client, CFG,
        ADP5588_AUTO_INC | ADP5588_INT_CFG | ADP5588_GPI_INT);

    return 0;

out:
    dev->irq_base = 0;
    return ret;
}

static void adp5588_irq_teardown(struct adp5588_gpio *dev)
{
    if (dev->irq_base)
        free_irq(dev->client->irq, dev);
}

#else
static int adp5588_irq_setup(struct adp5588_gpio *dev)
{
    struct i2c_client *client = dev->client;
    dev_warn(&client->dev, "interrupt support not compiled in\n");

    return 0;
}

static void adp5588_irq_teardown(struct adp5588_gpio *dev)
{
}
#endif /* CONFIG_GPIO_ADP5588_IRQ */

static int __devinit adp5588_gpio_probe(struct i2c_client *client,
                    const struct i2c_device_id *id)
{
    struct adp5588_gpio_platform_data *pdata = client->dev.platform_data;
    struct adp5588_gpio *dev;
    struct gpio_chip *gc;
    int ret, i, revid;

    if (pdata == NULL) {
        dev_err(&client->dev, "missing platform data\n");
        return -ENODEV;
    }

    if (!i2c_check_functionality(client->adapter,
                    I2C_FUNC_SMBUS_BYTE_DATA)) {
        dev_err(&client->dev, "SMBUS Byte Data not Supported\n");
        return -EIO;
    }

    dev = kzalloc(sizeof(*dev), GFP_KERNEL);
    if (dev == NULL) {
        dev_err(&client->dev, "failed to alloc memory\n");
        return -ENOMEM;
    }

    dev->client = client;

    gc = &dev->gpio_chip;
    gc->direction_input = adp5588_gpio_direction_input;
    gc->direction_output = adp5588_gpio_direction_output;
    gc->get = adp5588_gpio_get_value;
    gc->set = adp5588_gpio_set_value;
    gc->can_sleep = 1;

    gc->base = pdata->gpio_start;
    gc->ngpio = ADP5588_MAXGPIO;
    gc->label = client->name;
    gc->owner = THIS_MODULE;

    mutex_init(&dev->lock);

    ret = adp5588_gpio_read(dev->client, DEV_ID);
    if (ret < 0)
        goto err;

    revid = ret & ADP5588_DEVICE_ID_MASK;

    for (i = 0, ret = 0; i <= ADP5588_BANK(ADP5588_MAXGPIO); i++) {
        dev->dat_out[i] = adp5588_gpio_read(client, GPIO_DAT_OUT1 + i);
        dev->dir[i] = adp5588_gpio_read(client, GPIO_DIR1 + i);
        ret |= adp5588_gpio_write(client, KP_GPIO1 + i, 0);
        ret |= adp5588_gpio_write(client, GPIO_PULL1 + i,
                (pdata->pullup_dis_mask >> (8 * i)) & 0xFF);
        ret |= adp5588_gpio_write(client, GPIO_INT_EN1 + i, 0);
        if (ret)
            goto err;
    }

    if (pdata->irq_base) {
        if (WA_DELAYED_READOUT_REVID(revid)) {
            dev_warn(&client->dev, "GPIO int not supported\n");
        } else {
            ret = adp5588_irq_setup(dev);
            if (ret)
                goto err;
        }
    }

    ret = gpiochip_add(&dev->gpio_chip);
    if (ret)
        goto err_irq;

    dev_info(&client->dev, "IRQ Base: %d Rev.: %d\n",
            pdata->irq_base, revid);

    if (pdata->setup) {
        ret = pdata->setup(client, gc->base, gc->ngpio, pdata->context);
        if (ret < 0)
            dev_warn(&client->dev, "setup failed, %d\n", ret);
    }

    i2c_set_clientdata(client, dev);

    return 0;

err_irq:
    adp5588_irq_teardown(dev);
err:
    kfree(dev);
    return ret;
}

static int __devexit adp5588_gpio_remove(struct i2c_client *client)
{
    struct adp5588_gpio_platform_data *pdata = client->dev.platform_data;
    struct adp5588_gpio *dev = i2c_get_clientdata(client);
    int ret;

    if (pdata->teardown) {
        ret = pdata->teardown(client,
                      dev->gpio_chip.base, dev->gpio_chip.ngpio,
                      pdata->context);
        if (ret < 0) {
            dev_err(&client->dev, "teardown failed %d\n", ret);
            return ret;
        }
    }

    if (dev->irq_base)
        free_irq(dev->client->irq, dev);

    ret = gpiochip_remove(&dev->gpio_chip);
    if (ret) {
        dev_err(&client->dev, "gpiochip_remove failed %d\n", ret);
        return ret;
    }

    kfree(dev);
    return 0;
}

static const struct i2c_device_id adp5588_gpio_id[] = {
    {DRV_NAME, 0},
    {}
};

MODULE_DEVICE_TABLE(i2c, adp5588_gpio_id);

static struct i2c_driver adp5588_gpio_driver = {
    .driver = {
           .name = DRV_NAME,
           },
    .probe = adp5588_gpio_probe,
    .remove = __devexit_p(adp5588_gpio_remove),
    .id_table = adp5588_gpio_id,
};

module_i2c_driver(adp5588_gpio_driver);

MODULE_AUTHOR("Michael Hennerich <[email protected]>");
MODULE_DESCRIPTION("GPIO ADP5588 Driver");
MODULE_LICENSE("GPL");