1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright 2019 NXP.
4  */
5 
6 #include <linux/err.h>
7 #include <linux/device.h>
8 #include <linux/firmware/imx/sci.h>
9 #include <linux/init.h>
10 #include <linux/input.h>
11 #include <linux/interrupt.h>
12 #include <linux/jiffies.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/platform_device.h>
17 #include <linux/property.h>
18 
19 #define DEBOUNCE_TIME				30
20 #define REPEAT_INTERVAL				60
21 
22 #define SC_IRQ_BUTTON				1
23 #define SC_IRQ_GROUP_WAKE			3
24 
25 #define IMX_SC_MISC_FUNC_GET_BUTTON_STATUS	18
26 
27 struct imx_key_drv_data {
28 	u32 keycode;
29 	bool keystate;  /* true: pressed, false: released */
30 	struct delayed_work check_work;
31 	struct input_dev *input;
32 	struct imx_sc_ipc *key_ipc_handle;
33 	struct notifier_block key_notifier;
34 };
35 
36 struct imx_sc_msg_key {
37 	struct imx_sc_rpc_msg hdr;
38 	u32 state;
39 };
40 
imx_sc_key_notify(struct notifier_block * nb,unsigned long event,void * group)41 static int imx_sc_key_notify(struct notifier_block *nb,
42 			     unsigned long event, void *group)
43 {
44 	struct imx_key_drv_data *priv =
45 				 container_of(nb,
46 					      struct imx_key_drv_data,
47 					      key_notifier);
48 
49 	if ((event & SC_IRQ_BUTTON) && (*(u8 *)group == SC_IRQ_GROUP_WAKE)) {
50 		schedule_delayed_work(&priv->check_work,
51 				      msecs_to_jiffies(DEBOUNCE_TIME));
52 		pm_wakeup_event(priv->input->dev.parent, 0);
53 	}
54 
55 	return 0;
56 }
57 
imx_sc_check_for_events(struct work_struct * work)58 static void imx_sc_check_for_events(struct work_struct *work)
59 {
60 	struct imx_key_drv_data *priv =
61 				 container_of(work,
62 					      struct imx_key_drv_data,
63 					      check_work.work);
64 	struct input_dev *input = priv->input;
65 	struct imx_sc_msg_key msg;
66 	struct imx_sc_rpc_msg *hdr = &msg.hdr;
67 	bool state;
68 	int error;
69 
70 	hdr->ver = IMX_SC_RPC_VERSION;
71 	hdr->svc = IMX_SC_RPC_SVC_MISC;
72 	hdr->func = IMX_SC_MISC_FUNC_GET_BUTTON_STATUS;
73 	hdr->size = 1;
74 
75 	error = imx_scu_call_rpc(priv->key_ipc_handle, &msg, true);
76 	if (error) {
77 		dev_err(&input->dev, "read imx sc key failed, error %d\n", error);
78 		return;
79 	}
80 
81 	/*
82 	 * The response data from SCU firmware is 4 bytes,
83 	 * but ONLY the first byte is the key state, other
84 	 * 3 bytes could be some dirty data, so we should
85 	 * ONLY take the first byte as key state.
86 	 */
87 	state = (bool)(msg.state & 0xff);
88 
89 	if (state ^ priv->keystate) {
90 		priv->keystate = state;
91 		input_event(input, EV_KEY, priv->keycode, state);
92 		input_sync(input);
93 		if (!priv->keystate)
94 			pm_relax(priv->input->dev.parent);
95 	}
96 
97 	if (state)
98 		schedule_delayed_work(&priv->check_work,
99 				      msecs_to_jiffies(REPEAT_INTERVAL));
100 }
101 
imx_sc_key_action(void * data)102 static void imx_sc_key_action(void *data)
103 {
104 	struct imx_key_drv_data *priv = data;
105 
106 	imx_scu_irq_group_enable(SC_IRQ_GROUP_WAKE, SC_IRQ_BUTTON, false);
107 	imx_scu_irq_unregister_notifier(&priv->key_notifier);
108 	cancel_delayed_work_sync(&priv->check_work);
109 }
110 
imx_sc_key_probe(struct platform_device * pdev)111 static int imx_sc_key_probe(struct platform_device *pdev)
112 {
113 	struct imx_key_drv_data *priv;
114 	struct input_dev *input;
115 	int error;
116 
117 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
118 	if (!priv)
119 		return -ENOMEM;
120 
121 	error = imx_scu_get_handle(&priv->key_ipc_handle);
122 	if (error)
123 		return error;
124 
125 	if (device_property_read_u32(&pdev->dev, "linux,keycodes",
126 				     &priv->keycode)) {
127 		dev_err(&pdev->dev, "missing linux,keycodes property\n");
128 		return -EINVAL;
129 	}
130 
131 	INIT_DELAYED_WORK(&priv->check_work, imx_sc_check_for_events);
132 
133 	input = devm_input_allocate_device(&pdev->dev);
134 	if (!input) {
135 		dev_err(&pdev->dev, "failed to allocate the input device\n");
136 		return -ENOMEM;
137 	}
138 
139 	input->name = pdev->name;
140 	input->phys = "imx-sc-key/input0";
141 	input->id.bustype = BUS_HOST;
142 
143 	input_set_capability(input, EV_KEY, priv->keycode);
144 
145 	error = input_register_device(input);
146 	if (error) {
147 		dev_err(&pdev->dev, "failed to register input device\n");
148 		return error;
149 	}
150 
151 	priv->input = input;
152 	platform_set_drvdata(pdev, priv);
153 
154 	error = imx_scu_irq_group_enable(SC_IRQ_GROUP_WAKE, SC_IRQ_BUTTON,
155 					 true);
156 	if (error) {
157 		dev_err(&pdev->dev, "failed to enable scu group irq\n");
158 		return error;
159 	}
160 
161 	error = devm_add_action_or_reset(&pdev->dev, imx_sc_key_action, &priv);
162 	if (error)
163 		return error;
164 
165 	priv->key_notifier.notifier_call = imx_sc_key_notify;
166 	error = imx_scu_irq_register_notifier(&priv->key_notifier);
167 	if (error)
168 		dev_err(&pdev->dev, "failed to register scu notifier\n");
169 
170 	return error;
171 }
172 
173 static const struct of_device_id imx_sc_key_ids[] = {
174 	{ .compatible = "fsl,imx-sc-key" },
175 	{ /* sentinel */ }
176 };
177 MODULE_DEVICE_TABLE(of, imx_sc_key_ids);
178 
179 static struct platform_driver imx_sc_key_driver = {
180 	.driver = {
181 		.name = "imx-sc-key",
182 		.of_match_table = imx_sc_key_ids,
183 	},
184 	.probe = imx_sc_key_probe,
185 };
186 module_platform_driver(imx_sc_key_driver);
187 
188 MODULE_AUTHOR("Anson Huang <Anson.Huang@nxp.com>");
189 MODULE_DESCRIPTION("i.MX System Controller Key Driver");
190 MODULE_LICENSE("GPL v2");
191