1 /*
2  * NXP LPC32xx SoC Key Scan Interface
3  *
4  * Authors:
5  *    Kevin Wells <kevin.wells@nxp.com>
6  *    Roland Stigge <stigge@antcom.de>
7  *
8  * Copyright (C) 2010 NXP Semiconductors
9  * Copyright (C) 2012 Roland Stigge
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  *
22  * This controller supports square key matrices from 1x1 up to 8x8
23  */
24 
25 #include <linux/module.h>
26 #include <linux/interrupt.h>
27 #include <linux/slab.h>
28 #include <linux/irq.h>
29 #include <linux/pm.h>
30 #include <linux/platform_device.h>
31 #include <linux/input.h>
32 #include <linux/clk.h>
33 #include <linux/io.h>
34 #include <linux/of.h>
35 #include <linux/input/matrix_keypad.h>
36 
37 #define DRV_NAME				"lpc32xx_keys"
38 
39 /*
40  * Key scanner register offsets
41  */
42 #define LPC32XX_KS_DEB(x)			((x) + 0x00)
43 #define LPC32XX_KS_STATE_COND(x)		((x) + 0x04)
44 #define LPC32XX_KS_IRQ(x)			((x) + 0x08)
45 #define LPC32XX_KS_SCAN_CTL(x)			((x) + 0x0C)
46 #define LPC32XX_KS_FAST_TST(x)			((x) + 0x10)
47 #define LPC32XX_KS_MATRIX_DIM(x)		((x) + 0x14) /* 1..8 */
48 #define LPC32XX_KS_DATA(x, y)			((x) + 0x40 + ((y) << 2))
49 
50 #define LPC32XX_KSCAN_DEB_NUM_DEB_PASS(n)	((n) & 0xFF)
51 
52 #define LPC32XX_KSCAN_SCOND_IN_IDLE		0x0
53 #define LPC32XX_KSCAN_SCOND_IN_SCANONCE		0x1
54 #define LPC32XX_KSCAN_SCOND_IN_IRQGEN		0x2
55 #define LPC32XX_KSCAN_SCOND_IN_SCAN_MATRIX	0x3
56 
57 #define LPC32XX_KSCAN_IRQ_PENDING_CLR		0x1
58 
59 #define LPC32XX_KSCAN_SCTRL_SCAN_DELAY(n)	((n) & 0xFF)
60 
61 #define LPC32XX_KSCAN_FTST_FORCESCANONCE	0x1
62 #define LPC32XX_KSCAN_FTST_USE32K_CLK		0x2
63 
64 #define LPC32XX_KSCAN_MSEL_SELECT(n)		((n) & 0xF)
65 
66 struct lpc32xx_kscan_drv {
67 	struct input_dev *input;
68 	struct clk *clk;
69 	void __iomem *kscan_base;
70 	unsigned int irq;
71 
72 	u32 matrix_sz;		/* Size of matrix in XxY, ie. 3 = 3x3 */
73 	u32 deb_clks;		/* Debounce clocks (based on 32KHz clock) */
74 	u32 scan_delay;		/* Scan delay (based on 32KHz clock) */
75 
76 	unsigned short *keymap;	/* Pointer to key map for the scan matrix */
77 	unsigned int row_shift;
78 
79 	u8 lastkeystates[8];
80 };
81 
82 static void lpc32xx_mod_states(struct lpc32xx_kscan_drv *kscandat, int col)
83 {
84 	struct input_dev *input = kscandat->input;
85 	unsigned row, changed, scancode, keycode;
86 	u8 key;
87 
88 	key = readl(LPC32XX_KS_DATA(kscandat->kscan_base, col));
89 	changed = key ^ kscandat->lastkeystates[col];
90 	kscandat->lastkeystates[col] = key;
91 
92 	for (row = 0; changed; row++, changed >>= 1) {
93 		if (changed & 1) {
94 			/* Key state changed, signal an event */
95 			scancode = MATRIX_SCAN_CODE(row, col,
96 						    kscandat->row_shift);
97 			keycode = kscandat->keymap[scancode];
98 			input_event(input, EV_MSC, MSC_SCAN, scancode);
99 			input_report_key(input, keycode, key & (1 << row));
100 		}
101 	}
102 }
103 
104 static irqreturn_t lpc32xx_kscan_irq(int irq, void *dev_id)
105 {
106 	struct lpc32xx_kscan_drv *kscandat = dev_id;
107 	int i;
108 
109 	for (i = 0; i < kscandat->matrix_sz; i++)
110 		lpc32xx_mod_states(kscandat, i);
111 
112 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
113 
114 	input_sync(kscandat->input);
115 
116 	return IRQ_HANDLED;
117 }
118 
119 static int lpc32xx_kscan_open(struct input_dev *dev)
120 {
121 	struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
122 	int error;
123 
124 	error = clk_prepare_enable(kscandat->clk);
125 	if (error)
126 		return error;
127 
128 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
129 
130 	return 0;
131 }
132 
133 static void lpc32xx_kscan_close(struct input_dev *dev)
134 {
135 	struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
136 
137 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
138 	clk_disable_unprepare(kscandat->clk);
139 }
140 
141 static int lpc32xx_parse_dt(struct device *dev,
142 				      struct lpc32xx_kscan_drv *kscandat)
143 {
144 	struct device_node *np = dev->of_node;
145 	u32 rows = 0, columns = 0;
146 	int err;
147 
148 	err = matrix_keypad_parse_of_params(dev, &rows, &columns);
149 	if (err)
150 		return err;
151 	if (rows != columns) {
152 		dev_err(dev, "rows and columns must be equal!\n");
153 		return -EINVAL;
154 	}
155 
156 	kscandat->matrix_sz = rows;
157 	kscandat->row_shift = get_count_order(columns);
158 
159 	of_property_read_u32(np, "nxp,debounce-delay-ms", &kscandat->deb_clks);
160 	of_property_read_u32(np, "nxp,scan-delay-ms", &kscandat->scan_delay);
161 	if (!kscandat->deb_clks || !kscandat->scan_delay) {
162 		dev_err(dev, "debounce or scan delay not specified\n");
163 		return -EINVAL;
164 	}
165 
166 	return 0;
167 }
168 
169 static int lpc32xx_kscan_probe(struct platform_device *pdev)
170 {
171 	struct lpc32xx_kscan_drv *kscandat;
172 	struct input_dev *input;
173 	struct resource *res;
174 	size_t keymap_size;
175 	int error;
176 	int irq;
177 
178 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
179 	if (!res) {
180 		dev_err(&pdev->dev, "failed to get platform I/O memory\n");
181 		return -EINVAL;
182 	}
183 
184 	irq = platform_get_irq(pdev, 0);
185 	if (irq < 0 || irq >= NR_IRQS) {
186 		dev_err(&pdev->dev, "failed to get platform irq\n");
187 		return -EINVAL;
188 	}
189 
190 	kscandat = devm_kzalloc(&pdev->dev, sizeof(*kscandat),
191 				GFP_KERNEL);
192 	if (!kscandat)
193 		return -ENOMEM;
194 
195 	error = lpc32xx_parse_dt(&pdev->dev, kscandat);
196 	if (error) {
197 		dev_err(&pdev->dev, "failed to parse device tree\n");
198 		return error;
199 	}
200 
201 	keymap_size = sizeof(kscandat->keymap[0]) *
202 				(kscandat->matrix_sz << kscandat->row_shift);
203 	kscandat->keymap = devm_kzalloc(&pdev->dev, keymap_size, GFP_KERNEL);
204 	if (!kscandat->keymap)
205 		return -ENOMEM;
206 
207 	kscandat->input = input = devm_input_allocate_device(&pdev->dev);
208 	if (!input) {
209 		dev_err(&pdev->dev, "failed to allocate input device\n");
210 		return -ENOMEM;
211 	}
212 
213 	/* Setup key input */
214 	input->name		= pdev->name;
215 	input->phys		= "lpc32xx/input0";
216 	input->id.vendor	= 0x0001;
217 	input->id.product	= 0x0001;
218 	input->id.version	= 0x0100;
219 	input->open		= lpc32xx_kscan_open;
220 	input->close		= lpc32xx_kscan_close;
221 	input->dev.parent	= &pdev->dev;
222 
223 	input_set_capability(input, EV_MSC, MSC_SCAN);
224 
225 	error = matrix_keypad_build_keymap(NULL, NULL,
226 					   kscandat->matrix_sz,
227 					   kscandat->matrix_sz,
228 					   kscandat->keymap, kscandat->input);
229 	if (error) {
230 		dev_err(&pdev->dev, "failed to build keymap\n");
231 		return error;
232 	}
233 
234 	input_set_drvdata(kscandat->input, kscandat);
235 
236 	kscandat->kscan_base = devm_ioremap_resource(&pdev->dev, res);
237 	if (IS_ERR(kscandat->kscan_base))
238 		return PTR_ERR(kscandat->kscan_base);
239 
240 	/* Get the key scanner clock */
241 	kscandat->clk = devm_clk_get(&pdev->dev, NULL);
242 	if (IS_ERR(kscandat->clk)) {
243 		dev_err(&pdev->dev, "failed to get clock\n");
244 		return PTR_ERR(kscandat->clk);
245 	}
246 
247 	/* Configure the key scanner */
248 	error = clk_prepare_enable(kscandat->clk);
249 	if (error)
250 		return error;
251 
252 	writel(kscandat->deb_clks, LPC32XX_KS_DEB(kscandat->kscan_base));
253 	writel(kscandat->scan_delay, LPC32XX_KS_SCAN_CTL(kscandat->kscan_base));
254 	writel(LPC32XX_KSCAN_FTST_USE32K_CLK,
255 	       LPC32XX_KS_FAST_TST(kscandat->kscan_base));
256 	writel(kscandat->matrix_sz,
257 	       LPC32XX_KS_MATRIX_DIM(kscandat->kscan_base));
258 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
259 	clk_disable_unprepare(kscandat->clk);
260 
261 	error = devm_request_irq(&pdev->dev, irq, lpc32xx_kscan_irq, 0,
262 				 pdev->name, kscandat);
263 	if (error) {
264 		dev_err(&pdev->dev, "failed to request irq\n");
265 		return error;
266 	}
267 
268 	error = input_register_device(kscandat->input);
269 	if (error) {
270 		dev_err(&pdev->dev, "failed to register input device\n");
271 		return error;
272 	}
273 
274 	platform_set_drvdata(pdev, kscandat);
275 
276 	return 0;
277 }
278 
279 #ifdef CONFIG_PM_SLEEP
280 static int lpc32xx_kscan_suspend(struct device *dev)
281 {
282 	struct platform_device *pdev = to_platform_device(dev);
283 	struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
284 	struct input_dev *input = kscandat->input;
285 
286 	mutex_lock(&input->mutex);
287 
288 	if (input->users) {
289 		/* Clear IRQ and disable clock */
290 		writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
291 		clk_disable_unprepare(kscandat->clk);
292 	}
293 
294 	mutex_unlock(&input->mutex);
295 	return 0;
296 }
297 
298 static int lpc32xx_kscan_resume(struct device *dev)
299 {
300 	struct platform_device *pdev = to_platform_device(dev);
301 	struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
302 	struct input_dev *input = kscandat->input;
303 	int retval = 0;
304 
305 	mutex_lock(&input->mutex);
306 
307 	if (input->users) {
308 		/* Enable clock and clear IRQ */
309 		retval = clk_prepare_enable(kscandat->clk);
310 		if (retval == 0)
311 			writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
312 	}
313 
314 	mutex_unlock(&input->mutex);
315 	return retval;
316 }
317 #endif
318 
319 static SIMPLE_DEV_PM_OPS(lpc32xx_kscan_pm_ops, lpc32xx_kscan_suspend,
320 			 lpc32xx_kscan_resume);
321 
322 static const struct of_device_id lpc32xx_kscan_match[] = {
323 	{ .compatible = "nxp,lpc3220-key" },
324 	{},
325 };
326 MODULE_DEVICE_TABLE(of, lpc32xx_kscan_match);
327 
328 static struct platform_driver lpc32xx_kscan_driver = {
329 	.probe		= lpc32xx_kscan_probe,
330 	.driver		= {
331 		.name	= DRV_NAME,
332 		.pm	= &lpc32xx_kscan_pm_ops,
333 		.of_match_table = lpc32xx_kscan_match,
334 	}
335 };
336 
337 module_platform_driver(lpc32xx_kscan_driver);
338 
339 MODULE_LICENSE("GPL");
340 MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>");
341 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
342 MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");
343