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 	struct resource *iores;
70 	void __iomem *kscan_base;
71 	unsigned int irq;
72 
73 	u32 matrix_sz;		/* Size of matrix in XxY, ie. 3 = 3x3 */
74 	u32 deb_clks;		/* Debounce clocks (based on 32KHz clock) */
75 	u32 scan_delay;		/* Scan delay (based on 32KHz clock) */
76 
77 	unsigned short *keymap;	/* Pointer to key map for the scan matrix */
78 	unsigned int row_shift;
79 
80 	u8 lastkeystates[8];
81 };
82 
83 static void lpc32xx_mod_states(struct lpc32xx_kscan_drv *kscandat, int col)
84 {
85 	struct input_dev *input = kscandat->input;
86 	unsigned row, changed, scancode, keycode;
87 	u8 key;
88 
89 	key = readl(LPC32XX_KS_DATA(kscandat->kscan_base, col));
90 	changed = key ^ kscandat->lastkeystates[col];
91 	kscandat->lastkeystates[col] = key;
92 
93 	for (row = 0; changed; row++, changed >>= 1) {
94 		if (changed & 1) {
95 			/* Key state changed, signal an event */
96 			scancode = MATRIX_SCAN_CODE(row, col,
97 						    kscandat->row_shift);
98 			keycode = kscandat->keymap[scancode];
99 			input_event(input, EV_MSC, MSC_SCAN, scancode);
100 			input_report_key(input, keycode, key & (1 << row));
101 		}
102 	}
103 }
104 
105 static irqreturn_t lpc32xx_kscan_irq(int irq, void *dev_id)
106 {
107 	struct lpc32xx_kscan_drv *kscandat = dev_id;
108 	int i;
109 
110 	for (i = 0; i < kscandat->matrix_sz; i++)
111 		lpc32xx_mod_states(kscandat, i);
112 
113 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
114 
115 	input_sync(kscandat->input);
116 
117 	return IRQ_HANDLED;
118 }
119 
120 static int lpc32xx_kscan_open(struct input_dev *dev)
121 {
122 	struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
123 	int error;
124 
125 	error = clk_prepare_enable(kscandat->clk);
126 	if (error)
127 		return error;
128 
129 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
130 
131 	return 0;
132 }
133 
134 static void lpc32xx_kscan_close(struct input_dev *dev)
135 {
136 	struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
137 
138 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
139 	clk_disable_unprepare(kscandat->clk);
140 }
141 
142 static int lpc32xx_parse_dt(struct device *dev,
143 				      struct lpc32xx_kscan_drv *kscandat)
144 {
145 	struct device_node *np = dev->of_node;
146 	u32 rows = 0, columns = 0;
147 	int err;
148 
149 	err = matrix_keypad_parse_of_params(dev, &rows, &columns);
150 	if (err)
151 		return err;
152 	if (rows != columns) {
153 		dev_err(dev, "rows and columns must be equal!\n");
154 		return -EINVAL;
155 	}
156 
157 	kscandat->matrix_sz = rows;
158 	kscandat->row_shift = get_count_order(columns);
159 
160 	of_property_read_u32(np, "nxp,debounce-delay-ms", &kscandat->deb_clks);
161 	of_property_read_u32(np, "nxp,scan-delay-ms", &kscandat->scan_delay);
162 	if (!kscandat->deb_clks || !kscandat->scan_delay) {
163 		dev_err(dev, "debounce or scan delay not specified\n");
164 		return -EINVAL;
165 	}
166 
167 	return 0;
168 }
169 
170 static int lpc32xx_kscan_probe(struct platform_device *pdev)
171 {
172 	struct lpc32xx_kscan_drv *kscandat;
173 	struct input_dev *input;
174 	struct resource *res;
175 	size_t keymap_size;
176 	int error;
177 	int irq;
178 
179 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
180 	if (!res) {
181 		dev_err(&pdev->dev, "failed to get platform I/O memory\n");
182 		return -EINVAL;
183 	}
184 
185 	irq = platform_get_irq(pdev, 0);
186 	if (irq < 0 || irq >= NR_IRQS) {
187 		dev_err(&pdev->dev, "failed to get platform irq\n");
188 		return -EINVAL;
189 	}
190 
191 	kscandat = kzalloc(sizeof(struct lpc32xx_kscan_drv), GFP_KERNEL);
192 	if (!kscandat) {
193 		dev_err(&pdev->dev, "failed to allocate memory\n");
194 		return -ENOMEM;
195 	}
196 
197 	error = lpc32xx_parse_dt(&pdev->dev, kscandat);
198 	if (error) {
199 		dev_err(&pdev->dev, "failed to parse device tree\n");
200 		goto err_free_mem;
201 	}
202 
203 	keymap_size = sizeof(kscandat->keymap[0]) *
204 				(kscandat->matrix_sz << kscandat->row_shift);
205 	kscandat->keymap = kzalloc(keymap_size, GFP_KERNEL);
206 	if (!kscandat->keymap) {
207 		dev_err(&pdev->dev, "could not allocate memory for keymap\n");
208 		error = -ENOMEM;
209 		goto err_free_mem;
210 	}
211 
212 	kscandat->input = input = input_allocate_device();
213 	if (!input) {
214 		dev_err(&pdev->dev, "failed to allocate input device\n");
215 		error = -ENOMEM;
216 		goto err_free_keymap;
217 	}
218 
219 	/* Setup key input */
220 	input->name		= pdev->name;
221 	input->phys		= "lpc32xx/input0";
222 	input->id.vendor	= 0x0001;
223 	input->id.product	= 0x0001;
224 	input->id.version	= 0x0100;
225 	input->open		= lpc32xx_kscan_open;
226 	input->close		= lpc32xx_kscan_close;
227 	input->dev.parent	= &pdev->dev;
228 
229 	input_set_capability(input, EV_MSC, MSC_SCAN);
230 
231 	error = matrix_keypad_build_keymap(NULL, NULL,
232 					   kscandat->matrix_sz,
233 					   kscandat->matrix_sz,
234 					   kscandat->keymap, kscandat->input);
235 	if (error) {
236 		dev_err(&pdev->dev, "failed to build keymap\n");
237 		goto err_free_input;
238 	}
239 
240 	input_set_drvdata(kscandat->input, kscandat);
241 
242 	kscandat->iores = request_mem_region(res->start, resource_size(res),
243 					     pdev->name);
244 	if (!kscandat->iores) {
245 		dev_err(&pdev->dev, "failed to request I/O memory\n");
246 		error = -EBUSY;
247 		goto err_free_input;
248 	}
249 
250 	kscandat->kscan_base = ioremap(kscandat->iores->start,
251 				       resource_size(kscandat->iores));
252 	if (!kscandat->kscan_base) {
253 		dev_err(&pdev->dev, "failed to remap I/O memory\n");
254 		error = -EBUSY;
255 		goto err_release_memregion;
256 	}
257 
258 	/* Get the key scanner clock */
259 	kscandat->clk = clk_get(&pdev->dev, NULL);
260 	if (IS_ERR(kscandat->clk)) {
261 		dev_err(&pdev->dev, "failed to get clock\n");
262 		error = PTR_ERR(kscandat->clk);
263 		goto err_unmap;
264 	}
265 
266 	/* Configure the key scanner */
267 	error = clk_prepare_enable(kscandat->clk);
268 	if (error)
269 		goto err_clk_put;
270 
271 	writel(kscandat->deb_clks, LPC32XX_KS_DEB(kscandat->kscan_base));
272 	writel(kscandat->scan_delay, LPC32XX_KS_SCAN_CTL(kscandat->kscan_base));
273 	writel(LPC32XX_KSCAN_FTST_USE32K_CLK,
274 	       LPC32XX_KS_FAST_TST(kscandat->kscan_base));
275 	writel(kscandat->matrix_sz,
276 	       LPC32XX_KS_MATRIX_DIM(kscandat->kscan_base));
277 	writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
278 	clk_disable_unprepare(kscandat->clk);
279 
280 	error = request_irq(irq, lpc32xx_kscan_irq, 0, pdev->name, kscandat);
281 	if (error) {
282 		dev_err(&pdev->dev, "failed to request irq\n");
283 		goto err_clk_put;
284 	}
285 
286 	error = input_register_device(kscandat->input);
287 	if (error) {
288 		dev_err(&pdev->dev, "failed to register input device\n");
289 		goto err_free_irq;
290 	}
291 
292 	platform_set_drvdata(pdev, kscandat);
293 	return 0;
294 
295 err_free_irq:
296 	free_irq(irq, kscandat);
297 err_clk_put:
298 	clk_put(kscandat->clk);
299 err_unmap:
300 	iounmap(kscandat->kscan_base);
301 err_release_memregion:
302 	release_mem_region(kscandat->iores->start,
303 			   resource_size(kscandat->iores));
304 err_free_input:
305 	input_free_device(kscandat->input);
306 err_free_keymap:
307 	kfree(kscandat->keymap);
308 err_free_mem:
309 	kfree(kscandat);
310 
311 	return error;
312 }
313 
314 static int lpc32xx_kscan_remove(struct platform_device *pdev)
315 {
316 	struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
317 
318 	free_irq(platform_get_irq(pdev, 0), kscandat);
319 	clk_put(kscandat->clk);
320 	iounmap(kscandat->kscan_base);
321 	release_mem_region(kscandat->iores->start,
322 			   resource_size(kscandat->iores));
323 	input_unregister_device(kscandat->input);
324 	kfree(kscandat->keymap);
325 	kfree(kscandat);
326 
327 	return 0;
328 }
329 
330 #ifdef CONFIG_PM_SLEEP
331 static int lpc32xx_kscan_suspend(struct device *dev)
332 {
333 	struct platform_device *pdev = to_platform_device(dev);
334 	struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
335 	struct input_dev *input = kscandat->input;
336 
337 	mutex_lock(&input->mutex);
338 
339 	if (input->users) {
340 		/* Clear IRQ and disable clock */
341 		writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
342 		clk_disable_unprepare(kscandat->clk);
343 	}
344 
345 	mutex_unlock(&input->mutex);
346 	return 0;
347 }
348 
349 static int lpc32xx_kscan_resume(struct device *dev)
350 {
351 	struct platform_device *pdev = to_platform_device(dev);
352 	struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
353 	struct input_dev *input = kscandat->input;
354 	int retval = 0;
355 
356 	mutex_lock(&input->mutex);
357 
358 	if (input->users) {
359 		/* Enable clock and clear IRQ */
360 		retval = clk_prepare_enable(kscandat->clk);
361 		if (retval == 0)
362 			writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
363 	}
364 
365 	mutex_unlock(&input->mutex);
366 	return retval;
367 }
368 #endif
369 
370 static SIMPLE_DEV_PM_OPS(lpc32xx_kscan_pm_ops, lpc32xx_kscan_suspend,
371 			 lpc32xx_kscan_resume);
372 
373 static const struct of_device_id lpc32xx_kscan_match[] = {
374 	{ .compatible = "nxp,lpc3220-key" },
375 	{},
376 };
377 MODULE_DEVICE_TABLE(of, lpc32xx_kscan_match);
378 
379 static struct platform_driver lpc32xx_kscan_driver = {
380 	.probe		= lpc32xx_kscan_probe,
381 	.remove		= lpc32xx_kscan_remove,
382 	.driver		= {
383 		.name	= DRV_NAME,
384 		.owner	= THIS_MODULE,
385 		.pm	= &lpc32xx_kscan_pm_ops,
386 		.of_match_table = of_match_ptr(lpc32xx_kscan_match),
387 	}
388 };
389 
390 module_platform_driver(lpc32xx_kscan_driver);
391 
392 MODULE_LICENSE("GPL");
393 MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>");
394 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
395 MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");
396