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
66struct 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
82static 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
104static 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
119static 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
133static 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
141static 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
169static 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
280static 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
298static 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
319static SIMPLE_DEV_PM_OPS(lpc32xx_kscan_pm_ops, lpc32xx_kscan_suspend,
320			 lpc32xx_kscan_resume);
321
322static const struct of_device_id lpc32xx_kscan_match[] = {
323	{ .compatible = "nxp,lpc3220-key" },
324	{},
325};
326MODULE_DEVICE_TABLE(of, lpc32xx_kscan_match);
327
328static 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
337module_platform_driver(lpc32xx_kscan_driver);
338
339MODULE_LICENSE("GPL");
340MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>");
341MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
342MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");
343