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

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Samsung EXYNOS4x12 FIMC-IS (Imaging Subsystem) driver
   4 *
   5 * Copyright (C) 2013 Samsung Electronics Co., Ltd.
   6 *
   7 * Author: Sylwester Nawrocki <s.nawrocki@samsung.com>
   8 */
   9
  10#include <linux/clk.h>
  11#include <linux/module.h>
  12#include <linux/i2c.h>
  13#include <linux/platform_device.h>
  14#include <linux/pm_runtime.h>
  15#include <linux/slab.h>
  16#include "fimc-is-i2c.h"
  17
  18struct fimc_is_i2c {
  19        struct i2c_adapter adapter;
  20        struct clk *clock;
  21};
  22
  23/*
  24 * An empty algorithm is used as the actual I2C bus controller driver
  25 * is implemented in the FIMC-IS subsystem firmware and the host CPU
  26 * doesn't access the I2C bus controller.
  27 */
  28static u32 is_i2c_func(struct i2c_adapter *adap)
  29{
  30        return I2C_FUNC_I2C;
  31}
  32
  33static const struct i2c_algorithm fimc_is_i2c_algorithm = {
  34        .functionality  = is_i2c_func,
  35};
  36
  37static int fimc_is_i2c_probe(struct platform_device *pdev)
  38{
  39        struct device_node *node = pdev->dev.of_node;
  40        struct fimc_is_i2c *isp_i2c;
  41        struct i2c_adapter *i2c_adap;
  42        int ret;
  43
  44        isp_i2c = devm_kzalloc(&pdev->dev, sizeof(*isp_i2c), GFP_KERNEL);
  45        if (!isp_i2c)
  46                return -ENOMEM;
  47
  48        isp_i2c->clock = devm_clk_get(&pdev->dev, "i2c_isp");
  49        if (IS_ERR(isp_i2c->clock)) {
  50                dev_err(&pdev->dev, "failed to get the clock\n");
  51                return PTR_ERR(isp_i2c->clock);
  52        }
  53
  54        i2c_adap = &isp_i2c->adapter;
  55        i2c_adap->dev.of_node = node;
  56        i2c_adap->dev.parent = &pdev->dev;
  57        strscpy(i2c_adap->name, "exynos4x12-isp-i2c", sizeof(i2c_adap->name));
  58        i2c_adap->owner = THIS_MODULE;
  59        i2c_adap->algo = &fimc_is_i2c_algorithm;
  60        i2c_adap->class = I2C_CLASS_SPD;
  61
  62        platform_set_drvdata(pdev, isp_i2c);
  63        pm_runtime_enable(&pdev->dev);
  64
  65        ret = i2c_add_adapter(i2c_adap);
  66        if (ret < 0)
  67                goto err_pm_dis;
  68        /*
  69         * Client drivers of this adapter don't do any I2C transfers as that
  70         * is handled by the ISP firmware.  But we rely on the runtime PM
  71         * state propagation from the clients up to the adapter driver so
  72         * clear the ignore_children flags here.  PM rutnime calls are not
  73         * used in probe() handler of clients of this adapter so there is
  74         * no issues with clearing the flag right after registering the I2C
  75         * adapter.
  76         */
  77        pm_suspend_ignore_children(&i2c_adap->dev, false);
  78        return 0;
  79
  80err_pm_dis:
  81        pm_runtime_disable(&pdev->dev);
  82        return ret;
  83}
  84
  85static int fimc_is_i2c_remove(struct platform_device *pdev)
  86{
  87        struct fimc_is_i2c *isp_i2c = platform_get_drvdata(pdev);
  88
  89        pm_runtime_disable(&pdev->dev);
  90        i2c_del_adapter(&isp_i2c->adapter);
  91
  92        return 0;
  93}
  94
  95#ifdef CONFIG_PM
  96static int fimc_is_i2c_runtime_suspend(struct device *dev)
  97{
  98        struct fimc_is_i2c *isp_i2c = dev_get_drvdata(dev);
  99
 100        clk_disable_unprepare(isp_i2c->clock);
 101        return 0;
 102}
 103
 104static int fimc_is_i2c_runtime_resume(struct device *dev)
 105{
 106        struct fimc_is_i2c *isp_i2c = dev_get_drvdata(dev);
 107
 108        return clk_prepare_enable(isp_i2c->clock);
 109}
 110#endif
 111
 112#ifdef CONFIG_PM_SLEEP
 113static int fimc_is_i2c_suspend(struct device *dev)
 114{
 115        if (pm_runtime_suspended(dev))
 116                return 0;
 117
 118        return fimc_is_i2c_runtime_suspend(dev);
 119}
 120
 121static int fimc_is_i2c_resume(struct device *dev)
 122{
 123        if (pm_runtime_suspended(dev))
 124                return 0;
 125
 126        return fimc_is_i2c_runtime_resume(dev);
 127}
 128#endif
 129
 130static const struct dev_pm_ops fimc_is_i2c_pm_ops = {
 131        SET_RUNTIME_PM_OPS(fimc_is_i2c_runtime_suspend,
 132                                        fimc_is_i2c_runtime_resume, NULL)
 133        SET_SYSTEM_SLEEP_PM_OPS(fimc_is_i2c_suspend, fimc_is_i2c_resume)
 134};
 135
 136static const struct of_device_id fimc_is_i2c_of_match[] = {
 137        { .compatible = FIMC_IS_I2C_COMPATIBLE },
 138        { },
 139};
 140
 141static struct platform_driver fimc_is_i2c_driver = {
 142        .probe          = fimc_is_i2c_probe,
 143        .remove         = fimc_is_i2c_remove,
 144        .driver = {
 145                .of_match_table = fimc_is_i2c_of_match,
 146                .name           = "fimc-isp-i2c",
 147                .pm             = &fimc_is_i2c_pm_ops,
 148        }
 149};
 150
 151int fimc_is_register_i2c_driver(void)
 152{
 153        return platform_driver_register(&fimc_is_i2c_driver);
 154}
 155
 156void fimc_is_unregister_i2c_driver(void)
 157{
 158        platform_driver_unregister(&fimc_is_i2c_driver);
 159}
 160