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 const struct i2c_algorithm fimc_is_i2c_algorithm;
  32
  33 static 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
  76 err_pm_dis:
  77         pm_runtime_disable(&pdev->dev);
  78         return ret;
  79 }
  80
  81 static 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
  92 static 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
 100 static 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
 109 static 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
 117 static 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
 126 static 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
 132 static const struct of_device_id fimc_is_i2c_of_match[] = {
 133         { .compatible = FIMC_IS_I2C_COMPATIBLE },
 134         { },
 135 };
 136
 137 static 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
 147 int fimc_is_register_i2c_driver(void)
 148 {
 149         return platform_driver_register(&fimc_is_i2c_driver);
 150 }
 151
 152 void fimc_is_unregister_i2c_driver(void)
 153 {
 154         platform_driver_unregister(&fimc_is_i2c_driver);
 155 }