1 // SPDX-License-Identifier: GPL-2.0+
2 //
3 // Driver for the IMX SNVS ON/OFF Power Key
4 // Copyright (C) 2015 Freescale Semiconductor, Inc. All Rights Reserved.
5 
6 #include <linux/clk.h>
7 #include <linux/device.h>
8 #include <linux/err.h>
9 #include <linux/init.h>
10 #include <linux/input.h>
11 #include <linux/interrupt.h>
12 #include <linux/io.h>
13 #include <linux/jiffies.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/of.h>
17 #include <linux/of_address.h>
18 #include <linux/platform_device.h>
19 #include <linux/pm_wakeirq.h>
20 #include <linux/mfd/syscon.h>
21 #include <linux/regmap.h>
22 
23 #define SNVS_HPVIDR1_REG	0xF8
24 #define SNVS_LPSR_REG		0x4C	/* LP Status Register */
25 #define SNVS_LPCR_REG		0x38	/* LP Control Register */
26 #define SNVS_HPSR_REG		0x14
27 #define SNVS_HPSR_BTN		BIT(6)
28 #define SNVS_LPSR_SPO		BIT(18)
29 #define SNVS_LPCR_DEP_EN	BIT(5)
30 
31 #define DEBOUNCE_TIME		30
32 #define REPEAT_INTERVAL		60
33 
34 struct pwrkey_drv_data {
35 	struct regmap *snvs;
36 	int irq;
37 	int keycode;
38 	int keystate;  /* 1:pressed */
39 	int wakeup;
40 	struct timer_list check_timer;
41 	struct input_dev *input;
42 	u8 minor_rev;
43 };
44 
45 static void imx_imx_snvs_check_for_events(struct timer_list *t)
46 {
47 	struct pwrkey_drv_data *pdata = from_timer(pdata, t, check_timer);
48 	struct input_dev *input = pdata->input;
49 	u32 state;
50 
51 	regmap_read(pdata->snvs, SNVS_HPSR_REG, &state);
52 	state = state & SNVS_HPSR_BTN ? 1 : 0;
53 
54 	/* only report new event if status changed */
55 	if (state ^ pdata->keystate) {
56 		pdata->keystate = state;
57 		input_event(input, EV_KEY, pdata->keycode, state);
58 		input_sync(input);
59 		pm_relax(pdata->input->dev.parent);
60 	}
61 
62 	/* repeat check if pressed long */
63 	if (state) {
64 		mod_timer(&pdata->check_timer,
65 			  jiffies + msecs_to_jiffies(REPEAT_INTERVAL));
66 	}
67 }
68 
69 static irqreturn_t imx_snvs_pwrkey_interrupt(int irq, void *dev_id)
70 {
71 	struct platform_device *pdev = dev_id;
72 	struct pwrkey_drv_data *pdata = platform_get_drvdata(pdev);
73 	struct input_dev *input = pdata->input;
74 	u32 lp_status;
75 
76 	pm_wakeup_event(input->dev.parent, 0);
77 
78 	regmap_read(pdata->snvs, SNVS_LPSR_REG, &lp_status);
79 	if (lp_status & SNVS_LPSR_SPO) {
80 		if (pdata->minor_rev == 0) {
81 			/*
82 			 * The first generation i.MX6 SoCs only sends an
83 			 * interrupt on button release. To mimic power-key
84 			 * usage, we'll prepend a press event.
85 			 */
86 			input_report_key(input, pdata->keycode, 1);
87 			input_sync(input);
88 			input_report_key(input, pdata->keycode, 0);
89 			input_sync(input);
90 			pm_relax(input->dev.parent);
91 		} else {
92 			mod_timer(&pdata->check_timer,
93 			          jiffies + msecs_to_jiffies(DEBOUNCE_TIME));
94 		}
95 	}
96 
97 	/* clear SPO status */
98 	regmap_write(pdata->snvs, SNVS_LPSR_REG, SNVS_LPSR_SPO);
99 
100 	return IRQ_HANDLED;
101 }
102 
103 static void imx_snvs_pwrkey_disable_clk(void *data)
104 {
105 	clk_disable_unprepare(data);
106 }
107 
108 static void imx_snvs_pwrkey_act(void *pdata)
109 {
110 	struct pwrkey_drv_data *pd = pdata;
111 
112 	del_timer_sync(&pd->check_timer);
113 }
114 
115 static int imx_snvs_pwrkey_probe(struct platform_device *pdev)
116 {
117 	struct pwrkey_drv_data *pdata;
118 	struct input_dev *input;
119 	struct device_node *np;
120 	struct clk *clk;
121 	int error;
122 	u32 vid;
123 
124 	/* Get SNVS register Page */
125 	np = pdev->dev.of_node;
126 	if (!np)
127 		return -ENODEV;
128 
129 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
130 	if (!pdata)
131 		return -ENOMEM;
132 
133 	pdata->snvs = syscon_regmap_lookup_by_phandle(np, "regmap");
134 	if (IS_ERR(pdata->snvs)) {
135 		dev_err(&pdev->dev, "Can't get snvs syscon\n");
136 		return PTR_ERR(pdata->snvs);
137 	}
138 
139 	if (of_property_read_u32(np, "linux,keycode", &pdata->keycode)) {
140 		pdata->keycode = KEY_POWER;
141 		dev_warn(&pdev->dev, "KEY_POWER without setting in dts\n");
142 	}
143 
144 	clk = devm_clk_get_optional(&pdev->dev, NULL);
145 	if (IS_ERR(clk)) {
146 		dev_err(&pdev->dev, "Failed to get snvs clock (%pe)\n", clk);
147 		return PTR_ERR(clk);
148 	}
149 
150 	error = clk_prepare_enable(clk);
151 	if (error) {
152 		dev_err(&pdev->dev, "Failed to enable snvs clock (%pe)\n",
153 			ERR_PTR(error));
154 		return error;
155 	}
156 
157 	error = devm_add_action_or_reset(&pdev->dev,
158 					 imx_snvs_pwrkey_disable_clk, clk);
159 	if (error) {
160 		dev_err(&pdev->dev,
161 			"Failed to register clock cleanup handler (%pe)\n",
162 			ERR_PTR(error));
163 		return error;
164 	}
165 
166 	pdata->wakeup = of_property_read_bool(np, "wakeup-source");
167 
168 	pdata->irq = platform_get_irq(pdev, 0);
169 	if (pdata->irq < 0)
170 		return -EINVAL;
171 
172 	regmap_read(pdata->snvs, SNVS_HPVIDR1_REG, &vid);
173 	pdata->minor_rev = vid & 0xff;
174 
175 	regmap_update_bits(pdata->snvs, SNVS_LPCR_REG, SNVS_LPCR_DEP_EN, SNVS_LPCR_DEP_EN);
176 
177 	/* clear the unexpected interrupt before driver ready */
178 	regmap_write(pdata->snvs, SNVS_LPSR_REG, SNVS_LPSR_SPO);
179 
180 	timer_setup(&pdata->check_timer, imx_imx_snvs_check_for_events, 0);
181 
182 	input = devm_input_allocate_device(&pdev->dev);
183 	if (!input) {
184 		dev_err(&pdev->dev, "failed to allocate the input device\n");
185 		return -ENOMEM;
186 	}
187 
188 	input->name = pdev->name;
189 	input->phys = "snvs-pwrkey/input0";
190 	input->id.bustype = BUS_HOST;
191 
192 	input_set_capability(input, EV_KEY, pdata->keycode);
193 
194 	/* input customer action to cancel release timer */
195 	error = devm_add_action(&pdev->dev, imx_snvs_pwrkey_act, pdata);
196 	if (error) {
197 		dev_err(&pdev->dev, "failed to register remove action\n");
198 		return error;
199 	}
200 
201 	pdata->input = input;
202 	platform_set_drvdata(pdev, pdata);
203 
204 	error = devm_request_irq(&pdev->dev, pdata->irq,
205 			       imx_snvs_pwrkey_interrupt,
206 			       0, pdev->name, pdev);
207 
208 	if (error) {
209 		dev_err(&pdev->dev, "interrupt not available.\n");
210 		return error;
211 	}
212 
213 	error = input_register_device(input);
214 	if (error < 0) {
215 		dev_err(&pdev->dev, "failed to register input device\n");
216 		return error;
217 	}
218 
219 	device_init_wakeup(&pdev->dev, pdata->wakeup);
220 	error = dev_pm_set_wake_irq(&pdev->dev, pdata->irq);
221 	if (error)
222 		dev_err(&pdev->dev, "irq wake enable failed.\n");
223 
224 	return 0;
225 }
226 
227 static const struct of_device_id imx_snvs_pwrkey_ids[] = {
228 	{ .compatible = "fsl,sec-v4.0-pwrkey" },
229 	{ /* sentinel */ }
230 };
231 MODULE_DEVICE_TABLE(of, imx_snvs_pwrkey_ids);
232 
233 static struct platform_driver imx_snvs_pwrkey_driver = {
234 	.driver = {
235 		.name = "snvs_pwrkey",
236 		.of_match_table = imx_snvs_pwrkey_ids,
237 	},
238 	.probe = imx_snvs_pwrkey_probe,
239 };
240 module_platform_driver(imx_snvs_pwrkey_driver);
241 
242 MODULE_AUTHOR("Freescale Semiconductor");
243 MODULE_DESCRIPTION("i.MX snvs power key Driver");
244 MODULE_LICENSE("GPL");
245