xref: /linux/drivers/input/keyboard/lpc32xx-keys.c (revision be239684b18e1cdcafcf8c7face4a2f562c745ad) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * NXP LPC32xx SoC Key Scan Interface
4  *
5  * Authors:
6  *    Kevin Wells <kevin.wells@nxp.com>
7  *    Roland Stigge <stigge@antcom.de>
8  *
9  * Copyright (C) 2010 NXP Semiconductors
10  * Copyright (C) 2012 Roland Stigge
11  *
12  * This controller supports square key matrices from 1x1 up to 8x8
13  */
14 
15 #include <linux/module.h>
16 #include <linux/interrupt.h>
17 #include <linux/slab.h>
18 #include <linux/irq.h>
19 #include <linux/pm.h>
20 #include <linux/platform_device.h>
21 #include <linux/input.h>
22 #include <linux/clk.h>
23 #include <linux/io.h>
24 #include <linux/of.h>
25 #include <linux/input/matrix_keypad.h>
26 
27 #define DRV_NAME				"lpc32xx_keys"
28 
29 /*
30  * Key scanner register offsets
31  */
32 #define LPC32XX_KS_DEB(x)			((x) + 0x00)
33 #define LPC32XX_KS_STATE_COND(x)		((x) + 0x04)
34 #define LPC32XX_KS_IRQ(x)			((x) + 0x08)
35 #define LPC32XX_KS_SCAN_CTL(x)			((x) + 0x0C)
36 #define LPC32XX_KS_FAST_TST(x)			((x) + 0x10)
37 #define LPC32XX_KS_MATRIX_DIM(x)		((x) + 0x14) /* 1..8 */
38 #define LPC32XX_KS_DATA(x, y)			((x) + 0x40 + ((y) << 2))
39 
40 #define LPC32XX_KSCAN_DEB_NUM_DEB_PASS(n)	((n) & 0xFF)
41 
42 #define LPC32XX_KSCAN_SCOND_IN_IDLE		0x0
43 #define LPC32XX_KSCAN_SCOND_IN_SCANONCE		0x1
44 #define LPC32XX_KSCAN_SCOND_IN_IRQGEN		0x2
45 #define LPC32XX_KSCAN_SCOND_IN_SCAN_MATRIX	0x3
46 
47 #define LPC32XX_KSCAN_IRQ_PENDING_CLR		0x1
48 
49 #define LPC32XX_KSCAN_SCTRL_SCAN_DELAY(n)	((n) & 0xFF)
50 
51 #define LPC32XX_KSCAN_FTST_FORCESCANONCE	0x1
52 #define LPC32XX_KSCAN_FTST_USE32K_CLK		0x2
53 
54 #define LPC32XX_KSCAN_MSEL_SELECT(n)		((n) & 0xF)
55 
56 struct lpc32xx_kscan_drv {
57 	struct input_dev *input;
58 	struct clk *clk;
59 	void __iomem *kscan_base;
60 	unsigned int irq;
61 
62 	u32 matrix_sz;		/* Size of matrix in XxY, ie. 3 = 3x3 */
63 	u32 deb_clks;		/* Debounce clocks (based on 32KHz clock) */
64 	u32 scan_delay;		/* Scan delay (based on 32KHz clock) */
65 
66 	unsigned short *keymap;	/* Pointer to key map for the scan matrix */
67 	unsigned int row_shift;
68 
69 	u8 lastkeystates[8];
70 };
71 
72 static void lpc32xx_mod_states(struct lpc32xx_kscan_drv *kscandat, int col)
73 {
74 	struct input_dev *input = kscandat->input;
75 	unsigned row, changed, scancode, keycode;
76 	u8 key;
77 
78 	key = readl(LPC32XX_KS_DATA(kscandat->kscan_base, col));
79 	changed = key ^ kscandat->lastkeystates[col];
80 	kscandat->lastkeystates[col] = key;
81 
82 	for (row = 0; changed; row++, changed >>= 1) {
83 		if (changed & 1) {
84 			/* Key state changed, signal an event */
85 			scancode = MATRIX_SCAN_CODE(row, col,
86 						    kscandat->row_shift);
87 			keycode = kscandat->keymap[scancode];
88 			input_event(input, EV_MSC, MSC_SCAN, scancode);
89 			input_report_key(input, keycode, key & (1 << row));
90 		}
91 	}
92 }
93 
94 static irqreturn_t lpc32xx_kscan_irq(int irq, void *dev_id)
95 {
96 	struct lpc32xx_kscan_drv *kscandat = dev_id;
97 	int i;
98 
99 	for (i = 0; i < kscandat->matrix_sz; i++)
100 		lpc32xx_mod_states(kscandat, i);
101 
102 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
103 
104 	input_sync(kscandat->input);
105 
106 	return IRQ_HANDLED;
107 }
108 
109 static int lpc32xx_kscan_open(struct input_dev *dev)
110 {
111 	struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
112 	int error;
113 
114 	error = clk_prepare_enable(kscandat->clk);
115 	if (error)
116 		return error;
117 
118 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
119 
120 	return 0;
121 }
122 
123 static void lpc32xx_kscan_close(struct input_dev *dev)
124 {
125 	struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
126 
127 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
128 	clk_disable_unprepare(kscandat->clk);
129 }
130 
131 static int lpc32xx_parse_dt(struct device *dev,
132 				      struct lpc32xx_kscan_drv *kscandat)
133 {
134 	struct device_node *np = dev->of_node;
135 	u32 rows = 0, columns = 0;
136 	int err;
137 
138 	err = matrix_keypad_parse_properties(dev, &rows, &columns);
139 	if (err)
140 		return err;
141 	if (rows != columns) {
142 		dev_err(dev, "rows and columns must be equal!\n");
143 		return -EINVAL;
144 	}
145 
146 	kscandat->matrix_sz = rows;
147 	kscandat->row_shift = get_count_order(columns);
148 
149 	of_property_read_u32(np, "nxp,debounce-delay-ms", &kscandat->deb_clks);
150 	of_property_read_u32(np, "nxp,scan-delay-ms", &kscandat->scan_delay);
151 	if (!kscandat->deb_clks || !kscandat->scan_delay) {
152 		dev_err(dev, "debounce or scan delay not specified\n");
153 		return -EINVAL;
154 	}
155 
156 	return 0;
157 }
158 
159 static int lpc32xx_kscan_probe(struct platform_device *pdev)
160 {
161 	struct lpc32xx_kscan_drv *kscandat;
162 	struct input_dev *input;
163 	size_t keymap_size;
164 	int error;
165 	int irq;
166 
167 	irq = platform_get_irq(pdev, 0);
168 	if (irq < 0)
169 		return -EINVAL;
170 
171 	kscandat = devm_kzalloc(&pdev->dev, sizeof(*kscandat),
172 				GFP_KERNEL);
173 	if (!kscandat)
174 		return -ENOMEM;
175 
176 	error = lpc32xx_parse_dt(&pdev->dev, kscandat);
177 	if (error) {
178 		dev_err(&pdev->dev, "failed to parse device tree\n");
179 		return error;
180 	}
181 
182 	keymap_size = sizeof(kscandat->keymap[0]) *
183 				(kscandat->matrix_sz << kscandat->row_shift);
184 	kscandat->keymap = devm_kzalloc(&pdev->dev, keymap_size, GFP_KERNEL);
185 	if (!kscandat->keymap)
186 		return -ENOMEM;
187 
188 	kscandat->input = input = devm_input_allocate_device(&pdev->dev);
189 	if (!input) {
190 		dev_err(&pdev->dev, "failed to allocate input device\n");
191 		return -ENOMEM;
192 	}
193 
194 	/* Setup key input */
195 	input->name		= pdev->name;
196 	input->phys		= "lpc32xx/input0";
197 	input->id.vendor	= 0x0001;
198 	input->id.product	= 0x0001;
199 	input->id.version	= 0x0100;
200 	input->open		= lpc32xx_kscan_open;
201 	input->close		= lpc32xx_kscan_close;
202 	input->dev.parent	= &pdev->dev;
203 
204 	input_set_capability(input, EV_MSC, MSC_SCAN);
205 
206 	error = matrix_keypad_build_keymap(NULL, NULL,
207 					   kscandat->matrix_sz,
208 					   kscandat->matrix_sz,
209 					   kscandat->keymap, kscandat->input);
210 	if (error) {
211 		dev_err(&pdev->dev, "failed to build keymap\n");
212 		return error;
213 	}
214 
215 	input_set_drvdata(kscandat->input, kscandat);
216 
217 	kscandat->kscan_base = devm_platform_ioremap_resource(pdev, 0);
218 	if (IS_ERR(kscandat->kscan_base))
219 		return PTR_ERR(kscandat->kscan_base);
220 
221 	/* Get the key scanner clock */
222 	kscandat->clk = devm_clk_get(&pdev->dev, NULL);
223 	if (IS_ERR(kscandat->clk)) {
224 		dev_err(&pdev->dev, "failed to get clock\n");
225 		return PTR_ERR(kscandat->clk);
226 	}
227 
228 	/* Configure the key scanner */
229 	error = clk_prepare_enable(kscandat->clk);
230 	if (error)
231 		return error;
232 
233 	writel(kscandat->deb_clks, LPC32XX_KS_DEB(kscandat->kscan_base));
234 	writel(kscandat->scan_delay, LPC32XX_KS_SCAN_CTL(kscandat->kscan_base));
235 	writel(LPC32XX_KSCAN_FTST_USE32K_CLK,
236 	       LPC32XX_KS_FAST_TST(kscandat->kscan_base));
237 	writel(kscandat->matrix_sz,
238 	       LPC32XX_KS_MATRIX_DIM(kscandat->kscan_base));
239 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
240 	clk_disable_unprepare(kscandat->clk);
241 
242 	error = devm_request_irq(&pdev->dev, irq, lpc32xx_kscan_irq, 0,
243 				 pdev->name, kscandat);
244 	if (error) {
245 		dev_err(&pdev->dev, "failed to request irq\n");
246 		return error;
247 	}
248 
249 	error = input_register_device(kscandat->input);
250 	if (error) {
251 		dev_err(&pdev->dev, "failed to register input device\n");
252 		return error;
253 	}
254 
255 	platform_set_drvdata(pdev, kscandat);
256 
257 	return 0;
258 }
259 
260 static int lpc32xx_kscan_suspend(struct device *dev)
261 {
262 	struct platform_device *pdev = to_platform_device(dev);
263 	struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
264 	struct input_dev *input = kscandat->input;
265 
266 	mutex_lock(&input->mutex);
267 
268 	if (input_device_enabled(input)) {
269 		/* Clear IRQ and disable clock */
270 		writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
271 		clk_disable_unprepare(kscandat->clk);
272 	}
273 
274 	mutex_unlock(&input->mutex);
275 	return 0;
276 }
277 
278 static int lpc32xx_kscan_resume(struct device *dev)
279 {
280 	struct platform_device *pdev = to_platform_device(dev);
281 	struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
282 	struct input_dev *input = kscandat->input;
283 	int retval = 0;
284 
285 	mutex_lock(&input->mutex);
286 
287 	if (input_device_enabled(input)) {
288 		/* Enable clock and clear IRQ */
289 		retval = clk_prepare_enable(kscandat->clk);
290 		if (retval == 0)
291 			writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
292 	}
293 
294 	mutex_unlock(&input->mutex);
295 	return retval;
296 }
297 
298 static DEFINE_SIMPLE_DEV_PM_OPS(lpc32xx_kscan_pm_ops, lpc32xx_kscan_suspend,
299 				lpc32xx_kscan_resume);
300 
301 static const struct of_device_id lpc32xx_kscan_match[] = {
302 	{ .compatible = "nxp,lpc3220-key" },
303 	{},
304 };
305 MODULE_DEVICE_TABLE(of, lpc32xx_kscan_match);
306 
307 static struct platform_driver lpc32xx_kscan_driver = {
308 	.probe		= lpc32xx_kscan_probe,
309 	.driver		= {
310 		.name	= DRV_NAME,
311 		.pm	= pm_sleep_ptr(&lpc32xx_kscan_pm_ops),
312 		.of_match_table = lpc32xx_kscan_match,
313 	}
314 };
315 
316 module_platform_driver(lpc32xx_kscan_driver);
317 
318 MODULE_LICENSE("GPL");
319 MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>");
320 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
321 MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");
322