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 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
94static 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
102static 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
111static 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
119static 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
128static 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
134static const struct of_device_id fimc_is_i2c_of_match[] = {
135	{ .compatible = FIMC_IS_I2C_COMPATIBLE },
136	{ },
137};
138
139static 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
149int fimc_is_register_i2c_driver(void)
150{
151	return platform_driver_register(&fimc_is_i2c_driver);
152}
153
154void fimc_is_unregister_i2c_driver(void)
155{
156	platform_driver_unregister(&fimc_is_i2c_driver);
157}
158