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
56struct 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
72static 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
94static 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
109static 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
123static 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
131static 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
159static 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
260static 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
278static 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
298static DEFINE_SIMPLE_DEV_PM_OPS(lpc32xx_kscan_pm_ops, lpc32xx_kscan_suspend,
299				lpc32xx_kscan_resume);
300
301static const struct of_device_id lpc32xx_kscan_match[] = {
302	{ .compatible = "nxp,lpc3220-key" },
303	{},
304};
305MODULE_DEVICE_TABLE(of, lpc32xx_kscan_match);
306
307static 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
316module_platform_driver(lpc32xx_kscan_driver);
317
318MODULE_LICENSE("GPL");
319MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>");
320MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
321MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");
322