rfkill-gpio.c

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/*
 * Copyright (c) 2011, NVIDIA Corporation.
 *
 * 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, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rfkill.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/slab.h>

#include <linux/rfkill-gpio.h>

enum rfkill_gpio_clk_state {
    UNSPECIFIED = 0,
    PWR_ENABLED,
    PWR_DISABLED
};

#define PWR_CLK_SET(_RF, _EN) \
    ((_RF)->pwr_clk_enabled = (!(_EN) ? PWR_ENABLED : PWR_DISABLED))
#define PWR_CLK_ENABLED(_RF) ((_RF)->pwr_clk_enabled == PWR_ENABLED)
#define PWR_CLK_DISABLED(_RF) ((_RF)->pwr_clk_enabled != PWR_ENABLED)

struct rfkill_gpio_data {
    struct rfkill_gpio_platform_data    *pdata;
    struct rfkill               *rfkill_dev;
    char                    *reset_name;
    char                    *shutdown_name;
    enum rfkill_gpio_clk_state      pwr_clk_enabled;
    struct clk              *pwr_clk;
};

static int rfkill_gpio_set_power(void *data, bool blocked)
{
    struct rfkill_gpio_data *rfkill = data;

    if (blocked) {
        if (gpio_is_valid(rfkill->pdata->shutdown_gpio))
            gpio_direction_output(rfkill->pdata->shutdown_gpio, 0);
        if (gpio_is_valid(rfkill->pdata->reset_gpio))
            gpio_direction_output(rfkill->pdata->reset_gpio, 0);
        if (rfkill->pwr_clk && PWR_CLK_ENABLED(rfkill))
            clk_disable(rfkill->pwr_clk);
    } else {
        if (rfkill->pwr_clk && PWR_CLK_DISABLED(rfkill))
            clk_enable(rfkill->pwr_clk);
        if (gpio_is_valid(rfkill->pdata->reset_gpio))
            gpio_direction_output(rfkill->pdata->reset_gpio, 1);
        if (gpio_is_valid(rfkill->pdata->shutdown_gpio))
            gpio_direction_output(rfkill->pdata->shutdown_gpio, 1);
    }

    if (rfkill->pwr_clk)
        PWR_CLK_SET(rfkill, blocked);

    return 0;
}

static const struct rfkill_ops rfkill_gpio_ops = {
    .set_block = rfkill_gpio_set_power,
};

static int rfkill_gpio_probe(struct platform_device *pdev)
{
    struct rfkill_gpio_data *rfkill;
    struct rfkill_gpio_platform_data *pdata = pdev->dev.platform_data;
    int ret = 0;
    int len = 0;

    if (!pdata) {
        pr_warn("%s: No platform data specified\n", __func__);
        return -EINVAL;
    }

    /* make sure at-least one of the GPIO is defined and that
     * a name is specified for this instance */
    if (!pdata->name || (!gpio_is_valid(pdata->reset_gpio) &&
        !gpio_is_valid(pdata->shutdown_gpio))) {
        pr_warn("%s: invalid platform data\n", __func__);
        return -EINVAL;
    }

    rfkill = kzalloc(sizeof(*rfkill), GFP_KERNEL);
    if (!rfkill)
        return -ENOMEM;

    if (pdata->gpio_runtime_setup) {
        ret = pdata->gpio_runtime_setup(pdev);
        if (ret) {
            pr_warn("%s: can't set up gpio\n", __func__);
            goto fail_alloc;
        }
    }

    rfkill->pdata = pdata;

    len = strlen(pdata->name);
    rfkill->reset_name = kzalloc(len + 7, GFP_KERNEL);
    if (!rfkill->reset_name) {
        ret = -ENOMEM;
        goto fail_alloc;
    }

    rfkill->shutdown_name = kzalloc(len + 10, GFP_KERNEL);
    if (!rfkill->shutdown_name) {
        ret = -ENOMEM;
        goto fail_reset_name;
    }

    snprintf(rfkill->reset_name, len + 6 , "%s_reset", pdata->name);
    snprintf(rfkill->shutdown_name, len + 9, "%s_shutdown", pdata->name);

    if (pdata->power_clk_name) {
        rfkill->pwr_clk = clk_get(&pdev->dev, pdata->power_clk_name);
        if (IS_ERR(rfkill->pwr_clk)) {
            pr_warn("%s: can't find pwr_clk.\n", __func__);
            goto fail_shutdown_name;
        }
    }

    if (gpio_is_valid(pdata->reset_gpio)) {
        ret = gpio_request(pdata->reset_gpio, rfkill->reset_name);
        if (ret) {
            pr_warn("%s: failed to get reset gpio.\n", __func__);
            goto fail_clock;
        }
    }

    if (gpio_is_valid(pdata->shutdown_gpio)) {
        ret = gpio_request(pdata->shutdown_gpio, rfkill->shutdown_name);
        if (ret) {
            pr_warn("%s: failed to get shutdown gpio.\n", __func__);
            goto fail_reset;
        }
    }

    rfkill->rfkill_dev = rfkill_alloc(pdata->name, &pdev->dev, pdata->type,
                &rfkill_gpio_ops, rfkill);
    if (!rfkill->rfkill_dev)
        goto fail_shutdown;

    ret = rfkill_register(rfkill->rfkill_dev);
    if (ret < 0)
        goto fail_rfkill;

    platform_set_drvdata(pdev, rfkill);

    dev_info(&pdev->dev, "%s device registered.\n", pdata->name);

    return 0;

fail_rfkill:
    rfkill_destroy(rfkill->rfkill_dev);
fail_shutdown:
    if (gpio_is_valid(pdata->shutdown_gpio))
        gpio_free(pdata->shutdown_gpio);
fail_reset:
    if (gpio_is_valid(pdata->reset_gpio))
        gpio_free(pdata->reset_gpio);
fail_clock:
    if (rfkill->pwr_clk)
        clk_put(rfkill->pwr_clk);
fail_shutdown_name:
    kfree(rfkill->shutdown_name);
fail_reset_name:
    kfree(rfkill->reset_name);
fail_alloc:
    kfree(rfkill);

    return ret;
}

static int rfkill_gpio_remove(struct platform_device *pdev)
{
    struct rfkill_gpio_data *rfkill = platform_get_drvdata(pdev);
    struct rfkill_gpio_platform_data *pdata = pdev->dev.platform_data;

    if (pdata->gpio_runtime_close)
        pdata->gpio_runtime_close(pdev);
    rfkill_unregister(rfkill->rfkill_dev);
    rfkill_destroy(rfkill->rfkill_dev);
    if (gpio_is_valid(rfkill->pdata->shutdown_gpio))
        gpio_free(rfkill->pdata->shutdown_gpio);
    if (gpio_is_valid(rfkill->pdata->reset_gpio))
        gpio_free(rfkill->pdata->reset_gpio);
    if (rfkill->pwr_clk && PWR_CLK_ENABLED(rfkill))
        clk_disable(rfkill->pwr_clk);
    if (rfkill->pwr_clk)
        clk_put(rfkill->pwr_clk);
    kfree(rfkill->shutdown_name);
    kfree(rfkill->reset_name);
    kfree(rfkill);

    return 0;
}

static struct platform_driver rfkill_gpio_driver = {
    .probe = rfkill_gpio_probe,
    .remove = __devexit_p(rfkill_gpio_remove),
    .driver = {
           .name = "rfkill_gpio",
           .owner = THIS_MODULE,
    },
};

module_platform_driver(rfkill_gpio_driver);

MODULE_DESCRIPTION("gpio rfkill");
MODULE_AUTHOR("NVIDIA");
MODULE_LICENSE("GPL");