LXR linux/drivers/media/platform/exynos4-is/fimc-is-i2c.c

   1/*
   2 * Samsung EXYNOS4x12 FIMC-IS (Imaging Subsystem) driver
   3 *
   4 * Copyright (C) 2013 Samsung Electronics Co., Ltd.
   5 *
   6 * Author: Sylwester Nawrocki <s.nawrocki@samsung.com>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License version 2 as
  10 * published by the Free Software Foundation.
  11 */
  12
  13#include <linux/clk.h>
  14#include <linux/module.h>
  15#include <linux/i2c.h>
  16#include <linux/platform_device.h>
  17#include <linux/pm_runtime.h>
  18#include <linux/slab.h>
  19#include "fimc-is-i2c.h"
  20
  21struct fimc_is_i2c {
  22        struct i2c_adapter adapter;
  23        struct clk *clock;
  24};
  25
  26/*
  27 * An empty algorithm is used as the actual I2C bus controller driver
  28 * is implemented in the FIMC-IS subsystem firmware and the host CPU
  29 * doesn't access the I2C bus controller.
  30 */
  31static const struct i2c_algorithm fimc_is_i2c_algorithm;
  32
  33static int fimc_is_i2c_probe(struct platform_device *pdev)
  34{
  35        struct device_node *node = pdev->dev.of_node;
  36        struct fimc_is_i2c *isp_i2c;
  37        struct i2c_adapter *i2c_adap;
  38        int ret;
  39
  40        isp_i2c = devm_kzalloc(&pdev->dev, sizeof(*isp_i2c), GFP_KERNEL);
  41        if (!isp_i2c)
  42                return -ENOMEM;
  43
  44        isp_i2c->clock = devm_clk_get(&pdev->dev, "i2c_isp");
  45        if (IS_ERR(isp_i2c->clock)) {
  46                dev_err(&pdev->dev, "failed to get the clock\n");
  47                return PTR_ERR(isp_i2c->clock);
  48        }
  49
  50        i2c_adap = &isp_i2c->adapter;
  51        i2c_adap->dev.of_node = node;
  52        i2c_adap->dev.parent = &pdev->dev;
  53        strlcpy(i2c_adap->name, "exynos4x12-isp-i2c", sizeof(i2c_adap->name));
  54        i2c_adap->owner = THIS_MODULE;
  55        i2c_adap->algo = &fimc_is_i2c_algorithm;
  56        i2c_adap->class = I2C_CLASS_SPD;
  57
  58        platform_set_drvdata(pdev, isp_i2c);
  59        pm_runtime_enable(&pdev->dev);
  60
  61        ret = i2c_add_adapter(i2c_adap);
  62        if (ret < 0)
  63                goto err_pm_dis;
  64        /*
  65         * Client drivers of this adapter don't do any I2C transfers as that
  66         * is handled by the ISP firmware.  But we rely on the runtime PM
  67         * state propagation from the clients up to the adapter driver so
  68         * clear the ignore_children flags here.  PM rutnime calls are not
  69         * used in probe() handler of clients of this adapter so there is
  70         * no issues with clearing the flag right after registering the I2C
  71         * adapter.
  72         */
  73        pm_suspend_ignore_children(&i2c_adap->dev, false);
  74        return 0;
  75
  76err_pm_dis:
  77        pm_runtime_disable(&pdev->dev);
  78        return ret;
  79}
  80
  81static int fimc_is_i2c_remove(struct platform_device *pdev)
  82{
  83        struct fimc_is_i2c *isp_i2c = platform_get_drvdata(pdev);
  84
  85        pm_runtime_disable(&pdev->dev);
  86        i2c_del_adapter(&isp_i2c->adapter);
  87
  88        return 0;
  89}
  90
  91#ifdef CONFIG_PM
  92static int fimc_is_i2c_runtime_suspend(struct device *dev)
  93{
  94        struct fimc_is_i2c *isp_i2c = dev_get_drvdata(dev);
  95
  96        clk_disable_unprepare(isp_i2c->clock);
  97        return 0;
  98}
  99
 100static int fimc_is_i2c_runtime_resume(struct device *dev)
 101{
 102        struct fimc_is_i2c *isp_i2c = dev_get_drvdata(dev);
 103
 104        return clk_prepare_enable(isp_i2c->clock);
 105}
 106#endif
 107
 108#ifdef CONFIG_PM_SLEEP
 109static int fimc_is_i2c_suspend(struct device *dev)
 110{
 111        if (pm_runtime_suspended(dev))
 112                return 0;
 113
 114        return fimc_is_i2c_runtime_suspend(dev);
 115}
 116
 117static int fimc_is_i2c_resume(struct device *dev)
 118{
 119        if (pm_runtime_suspended(dev))
 120                return 0;
 121
 122        return fimc_is_i2c_runtime_resume(dev);
 123}
 124#endif
 125
 126static struct dev_pm_ops fimc_is_i2c_pm_ops = {
 127        SET_RUNTIME_PM_OPS(fimc_is_i2c_runtime_suspend,
 128                                        fimc_is_i2c_runtime_resume, NULL)
 129        SET_SYSTEM_SLEEP_PM_OPS(fimc_is_i2c_suspend, fimc_is_i2c_resume)
 130};
 131
 132static const struct of_device_id fimc_is_i2c_of_match[] = {
 133        { .compatible = FIMC_IS_I2C_COMPATIBLE },
 134        { },
 135};
 136
 137static struct platform_driver fimc_is_i2c_driver = {
 138        .probe          = fimc_is_i2c_probe,
 139        .remove         = fimc_is_i2c_remove,
 140        .driver = {
 141                .of_match_table = fimc_is_i2c_of_match,
 142                .name           = "fimc-isp-i2c",
 143                .pm             = &fimc_is_i2c_pm_ops,
 144        }
 145};
 146
 147int fimc_is_register_i2c_driver(void)
 148{
 149        return platform_driver_register(&fimc_is_i2c_driver);
 150}
 151
 152void fimc_is_unregister_i2c_driver(void)
 153{
 154        platform_driver_unregister(&fimc_is_i2c_driver);
 155}
 156