xref: /linux/drivers/input/keyboard/lpc32xx-keys.c (revision d7f39aee79f04eeaa42085728423501b33ac5be5) 
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 
61 	u32 matrix_sz;		/* Size of matrix in XxY, ie. 3 = 3x3 */
62 	u32 deb_clks;		/* Debounce clocks (based on 32KHz clock) */
63 	u32 scan_delay;		/* Scan delay (based on 32KHz clock) */
64 
65 	unsigned int row_shift;
66 	unsigned short *keymap;	/* Pointer to key map for the scan matrix */
67 
68 	u8 lastkeystates[8];
69 };
70 
71 static void lpc32xx_mod_states(struct lpc32xx_kscan_drv *kscandat, int col)
72 {
73 	struct input_dev *input = kscandat->input;
74 	unsigned row, changed, scancode, keycode;
75 	u8 key;
76 
77 	key = readl(LPC32XX_KS_DATA(kscandat->kscan_base, col));
78 	changed = key ^ kscandat->lastkeystates[col];
79 	kscandat->lastkeystates[col] = key;
80 
81 	for (row = 0; changed; row++, changed >>= 1) {
82 		if (changed & 1) {
83 			/* Key state changed, signal an event */
84 			scancode = MATRIX_SCAN_CODE(row, col,
85 						    kscandat->row_shift);
86 			keycode = kscandat->keymap[scancode];
87 			input_event(input, EV_MSC, MSC_SCAN, scancode);
88 			input_report_key(input, keycode, key & (1 << row));
89 		}
90 	}
91 }
92 
93 static irqreturn_t lpc32xx_kscan_irq(int irq, void *dev_id)
94 {
95 	struct lpc32xx_kscan_drv *kscandat = dev_id;
96 	int i;
97 
98 	for (i = 0; i < kscandat->matrix_sz; i++)
99 		lpc32xx_mod_states(kscandat, i);
100 
101 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
102 
103 	input_sync(kscandat->input);
104 
105 	return IRQ_HANDLED;
106 }
107 
108 static int lpc32xx_kscan_open(struct input_dev *dev)
109 {
110 	struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
111 	int error;
112 
113 	error = clk_prepare_enable(kscandat->clk);
114 	if (error)
115 		return error;
116 
117 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
118 
119 	return 0;
120 }
121 
122 static void lpc32xx_kscan_close(struct input_dev *dev)
123 {
124 	struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
125 
126 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
127 	clk_disable_unprepare(kscandat->clk);
128 }
129 
130 static int lpc32xx_parse_dt(struct device *dev,
131 				      struct lpc32xx_kscan_drv *kscandat)
132 {
133 	struct device_node *np = dev->of_node;
134 	u32 rows = 0, columns = 0;
135 	int err;
136 
137 	err = matrix_keypad_parse_properties(dev, &rows, &columns);
138 	if (err)
139 		return err;
140 	if (rows != columns) {
141 		dev_err(dev, "rows and columns must be equal!\n");
142 		return -EINVAL;
143 	}
144 
145 	kscandat->matrix_sz = rows;
146 	kscandat->row_shift = get_count_order(columns);
147 
148 	of_property_read_u32(np, "nxp,debounce-delay-ms", &kscandat->deb_clks);
149 	of_property_read_u32(np, "nxp,scan-delay-ms", &kscandat->scan_delay);
150 	if (!kscandat->deb_clks || !kscandat->scan_delay) {
151 		dev_err(dev, "debounce or scan delay not specified\n");
152 		return -EINVAL;
153 	}
154 
155 	return 0;
156 }
157 
158 static int lpc32xx_kscan_probe(struct platform_device *pdev)
159 {
160 	struct lpc32xx_kscan_drv *kscandat;
161 	struct input_dev *input;
162 	size_t keymap_size;
163 	int error;
164 	int irq;
165 
166 	irq = platform_get_irq(pdev, 0);
167 	if (irq < 0)
168 		return -EINVAL;
169 
170 	kscandat = devm_kzalloc(&pdev->dev, sizeof(*kscandat),
171 				GFP_KERNEL);
172 	if (!kscandat)
173 		return -ENOMEM;
174 
175 	error = lpc32xx_parse_dt(&pdev->dev, kscandat);
176 	if (error) {
177 		dev_err(&pdev->dev, "failed to parse device tree\n");
178 		return error;
179 	}
180 
181 	keymap_size = sizeof(kscandat->keymap[0]) *
182 				(kscandat->matrix_sz << kscandat->row_shift);
183 	kscandat->keymap = devm_kzalloc(&pdev->dev, keymap_size, GFP_KERNEL);
184 	if (!kscandat->keymap)
185 		return -ENOMEM;
186 
187 	kscandat->input = input = devm_input_allocate_device(&pdev->dev);
188 	if (!input) {
189 		dev_err(&pdev->dev, "failed to allocate input device\n");
190 		return -ENOMEM;
191 	}
192 
193 	/* Setup key input */
194 	input->name		= pdev->name;
195 	input->phys		= "lpc32xx/input0";
196 	input->id.vendor	= 0x0001;
197 	input->id.product	= 0x0001;
198 	input->id.version	= 0x0100;
199 	input->open		= lpc32xx_kscan_open;
200 	input->close		= lpc32xx_kscan_close;
201 	input->dev.parent	= &pdev->dev;
202 
203 	input_set_capability(input, EV_MSC, MSC_SCAN);
204 
205 	error = matrix_keypad_build_keymap(NULL, NULL,
206 					   kscandat->matrix_sz,
207 					   kscandat->matrix_sz,
208 					   kscandat->keymap, kscandat->input);
209 	if (error) {
210 		dev_err(&pdev->dev, "failed to build keymap\n");
211 		return error;
212 	}
213 
214 	input_set_drvdata(kscandat->input, kscandat);
215 
216 	kscandat->kscan_base = devm_platform_ioremap_resource(pdev, 0);
217 	if (IS_ERR(kscandat->kscan_base))
218 		return PTR_ERR(kscandat->kscan_base);
219 
220 	/* Get the key scanner clock */
221 	kscandat->clk = devm_clk_get(&pdev->dev, NULL);
222 	if (IS_ERR(kscandat->clk)) {
223 		dev_err(&pdev->dev, "failed to get clock\n");
224 		return PTR_ERR(kscandat->clk);
225 	}
226 
227 	/* Configure the key scanner */
228 	error = clk_prepare_enable(kscandat->clk);
229 	if (error)
230 		return error;
231 
232 	writel(kscandat->deb_clks, LPC32XX_KS_DEB(kscandat->kscan_base));
233 	writel(kscandat->scan_delay, LPC32XX_KS_SCAN_CTL(kscandat->kscan_base));
234 	writel(LPC32XX_KSCAN_FTST_USE32K_CLK,
235 	       LPC32XX_KS_FAST_TST(kscandat->kscan_base));
236 	writel(kscandat->matrix_sz,
237 	       LPC32XX_KS_MATRIX_DIM(kscandat->kscan_base));
238 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
239 	clk_disable_unprepare(kscandat->clk);
240 
241 	error = devm_request_irq(&pdev->dev, irq, lpc32xx_kscan_irq, 0,
242 				 pdev->name, kscandat);
243 	if (error) {
244 		dev_err(&pdev->dev, "failed to request irq\n");
245 		return error;
246 	}
247 
248 	error = input_register_device(kscandat->input);
249 	if (error) {
250 		dev_err(&pdev->dev, "failed to register input device\n");
251 		return error;
252 	}
253 
254 	platform_set_drvdata(pdev, kscandat);
255 
256 	return 0;
257 }
258 
259 static int lpc32xx_kscan_suspend(struct device *dev)
260 {
261 	struct platform_device *pdev = to_platform_device(dev);
262 	struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
263 	struct input_dev *input = kscandat->input;
264 
265 	mutex_lock(&input->mutex);
266 
267 	if (input_device_enabled(input)) {
268 		/* Clear IRQ and disable clock */
269 		writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
270 		clk_disable_unprepare(kscandat->clk);
271 	}
272 
273 	mutex_unlock(&input->mutex);
274 	return 0;
275 }
276 
277 static int lpc32xx_kscan_resume(struct device *dev)
278 {
279 	struct platform_device *pdev = to_platform_device(dev);
280 	struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
281 	struct input_dev *input = kscandat->input;
282 	int retval = 0;
283 
284 	mutex_lock(&input->mutex);
285 
286 	if (input_device_enabled(input)) {
287 		/* Enable clock and clear IRQ */
288 		retval = clk_prepare_enable(kscandat->clk);
289 		if (retval == 0)
290 			writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
291 	}
292 
293 	mutex_unlock(&input->mutex);
294 	return retval;
295 }
296 
297 static DEFINE_SIMPLE_DEV_PM_OPS(lpc32xx_kscan_pm_ops, lpc32xx_kscan_suspend,
298 				lpc32xx_kscan_resume);
299 
300 static const struct of_device_id lpc32xx_kscan_match[] = {
301 	{ .compatible = "nxp,lpc3220-key" },
302 	{},
303 };
304 MODULE_DEVICE_TABLE(of, lpc32xx_kscan_match);
305 
306 static struct platform_driver lpc32xx_kscan_driver = {
307 	.probe		= lpc32xx_kscan_probe,
308 	.driver		= {
309 		.name	= DRV_NAME,
310 		.pm	= pm_sleep_ptr(&lpc32xx_kscan_pm_ops),
311 		.of_match_table = lpc32xx_kscan_match,
312 	}
313 };
314 
315 module_platform_driver(lpc32xx_kscan_driver);
316 
317 MODULE_LICENSE("GPL");
318 MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>");
319 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
320 MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");
321