drivers/media/platform/samsung/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
  18 struct 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  */
  28 static u32 is_i2c_func(struct i2c_adapter *adap)
  29 {
  30         return I2C_FUNC_I2C;
  31 }
  32
  33 static const struct i2c_algorithm fimc_is_i2c_algorithm = {
  34         .functionality  = is_i2c_func,
  35 };
  36
  37 static 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
  80 err_pm_dis:
  81         pm_runtime_disable(&pdev->dev);
  82         return ret;
  83 }
  84
  85 static void 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
  93 #ifdef CONFIG_PM
  94 static int fimc_is_i2c_runtime_suspend(struct device *dev)
  95 {
  96         struct fimc_is_i2c *isp_i2c = dev_get_drvdata(dev);
  97
  98         clk_disable_unprepare(isp_i2c->clock);
  99         return 0;
 100 }
 101
 102 static int fimc_is_i2c_runtime_resume(struct device *dev)
 103 {
 104         struct fimc_is_i2c *isp_i2c = dev_get_drvdata(dev);
 105
 106         return clk_prepare_enable(isp_i2c->clock);
 107 }
 108 #endif
 109
 110 #ifdef CONFIG_PM_SLEEP
 111 static int fimc_is_i2c_suspend(struct device *dev)
 112 {
 113         if (pm_runtime_suspended(dev))
 114                 return 0;
 115
 116         return fimc_is_i2c_runtime_suspend(dev);
 117 }
 118
 119 static int fimc_is_i2c_resume(struct device *dev)
 120 {
 121         if (pm_runtime_suspended(dev))
 122                 return 0;
 123
 124         return fimc_is_i2c_runtime_resume(dev);
 125 }
 126 #endif
 127
 128 static const struct dev_pm_ops fimc_is_i2c_pm_ops = {
 129         SET_RUNTIME_PM_OPS(fimc_is_i2c_runtime_suspend,
 130                                         fimc_is_i2c_runtime_resume, NULL)
 131         SET_SYSTEM_SLEEP_PM_OPS(fimc_is_i2c_suspend, fimc_is_i2c_resume)
 132 };
 133
 134 static const struct of_device_id fimc_is_i2c_of_match[] = {
 135         { .compatible = FIMC_IS_I2C_COMPATIBLE },
 136         { },
 137 };
 138
 139 static struct platform_driver fimc_is_i2c_driver = {
 140         .probe          = fimc_is_i2c_probe,
 141         .remove_new     = fimc_is_i2c_remove,
 142         .driver = {
 143                 .of_match_table = fimc_is_i2c_of_match,
 144                 .name           = "fimc-isp-i2c",
 145                 .pm             = &fimc_is_i2c_pm_ops,
 146         }
 147 };
 148
 149 int fimc_is_register_i2c_driver(void)
 150 {
 151         return platform_driver_register(&fimc_is_i2c_driver);
 152 }
 153
 154 void fimc_is_unregister_i2c_driver(void)
 155 {
 156         platform_driver_unregister(&fimc_is_i2c_driver);
 157 }