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 }
158