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
  21 struct 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  */
  31 static u32 is_i2c_func(struct i2c_adapter *adap)
  32 {
  33         return I2C_FUNC_I2C;
  34 }
  35
  36 static const struct i2c_algorithm fimc_is_i2c_algorithm = {
  37         .functionality  = is_i2c_func,
  38 };
  39
  40 static int fimc_is_i2c_probe(struct platform_device *pdev)
  41 {
  42         struct device_node *node = pdev->dev.of_node;
  43         struct fimc_is_i2c *isp_i2c;
  44         struct i2c_adapter *i2c_adap;
  45         int ret;
  46
  47         isp_i2c = devm_kzalloc(&pdev->dev, sizeof(*isp_i2c), GFP_KERNEL);
  48         if (!isp_i2c)
  49                 return -ENOMEM;
  50
  51         isp_i2c->clock = devm_clk_get(&pdev->dev, "i2c_isp");
  52         if (IS_ERR(isp_i2c->clock)) {
  53                 dev_err(&pdev->dev, "failed to get the clock\n");
  54                 return PTR_ERR(isp_i2c->clock);
  55         }
  56
  57         i2c_adap = &isp_i2c->adapter;
  58         i2c_adap->dev.of_node = node;
  59         i2c_adap->dev.parent = &pdev->dev;
  60         strscpy(i2c_adap->name, "exynos4x12-isp-i2c", sizeof(i2c_adap->name));
  61         i2c_adap->owner = THIS_MODULE;
  62         i2c_adap->algo = &fimc_is_i2c_algorithm;
  63         i2c_adap->class = I2C_CLASS_SPD;
  64
  65         platform_set_drvdata(pdev, isp_i2c);
  66         pm_runtime_enable(&pdev->dev);
  67
  68         ret = i2c_add_adapter(i2c_adap);
  69         if (ret < 0)
  70                 goto err_pm_dis;
  71         /*
  72          * Client drivers of this adapter don't do any I2C transfers as that
  73          * is handled by the ISP firmware.  But we rely on the runtime PM
  74          * state propagation from the clients up to the adapter driver so
  75          * clear the ignore_children flags here.  PM rutnime calls are not
  76          * used in probe() handler of clients of this adapter so there is
  77          * no issues with clearing the flag right after registering the I2C
  78          * adapter.
  79          */
  80         pm_suspend_ignore_children(&i2c_adap->dev, false);
  81         return 0;
  82
  83 err_pm_dis:
  84         pm_runtime_disable(&pdev->dev);
  85         return ret;
  86 }
  87
  88 static int fimc_is_i2c_remove(struct platform_device *pdev)
  89 {
  90         struct fimc_is_i2c *isp_i2c = platform_get_drvdata(pdev);
  91
  92         pm_runtime_disable(&pdev->dev);
  93         i2c_del_adapter(&isp_i2c->adapter);
  94
  95         return 0;
  96 }
  97
  98 #ifdef CONFIG_PM
  99 static int fimc_is_i2c_runtime_suspend(struct device *dev)
 100 {
 101         struct fimc_is_i2c *isp_i2c = dev_get_drvdata(dev);
 102
 103         clk_disable_unprepare(isp_i2c->clock);
 104         return 0;
 105 }
 106
 107 static int fimc_is_i2c_runtime_resume(struct device *dev)
 108 {
 109         struct fimc_is_i2c *isp_i2c = dev_get_drvdata(dev);
 110
 111         return clk_prepare_enable(isp_i2c->clock);
 112 }
 113 #endif
 114
 115 #ifdef CONFIG_PM_SLEEP
 116 static int fimc_is_i2c_suspend(struct device *dev)
 117 {
 118         if (pm_runtime_suspended(dev))
 119                 return 0;
 120
 121         return fimc_is_i2c_runtime_suspend(dev);
 122 }
 123
 124 static int fimc_is_i2c_resume(struct device *dev)
 125 {
 126         if (pm_runtime_suspended(dev))
 127                 return 0;
 128
 129         return fimc_is_i2c_runtime_resume(dev);
 130 }
 131 #endif
 132
 133 static const struct dev_pm_ops fimc_is_i2c_pm_ops = {
 134         SET_RUNTIME_PM_OPS(fimc_is_i2c_runtime_suspend,
 135                                         fimc_is_i2c_runtime_resume, NULL)
 136         SET_SYSTEM_SLEEP_PM_OPS(fimc_is_i2c_suspend, fimc_is_i2c_resume)
 137 };
 138
 139 static const struct of_device_id fimc_is_i2c_of_match[] = {
 140         { .compatible = FIMC_IS_I2C_COMPATIBLE },
 141         { },
 142 };
 143
 144 static struct platform_driver fimc_is_i2c_driver = {
 145         .probe          = fimc_is_i2c_probe,
 146         .remove         = fimc_is_i2c_remove,
 147         .driver = {
 148                 .of_match_table = fimc_is_i2c_of_match,
 149                 .name           = "fimc-isp-i2c",
 150                 .pm             = &fimc_is_i2c_pm_ops,
 151         }
 152 };
 153
 154 int fimc_is_register_i2c_driver(void)
 155 {
 156         return platform_driver_register(&fimc_is_i2c_driver);
 157 }
 158
 159 void fimc_is_unregister_i2c_driver(void)
 160 {
 161         platform_driver_unregister(&fimc_is_i2c_driver);
 162 }