lpc32xx-keys.c

  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
 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
 71static 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
 93static 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
108static 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
122static 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
130static 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
158static 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
259static 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	guard(mutex)(&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	return 0;
274}
275
276static int lpc32xx_kscan_resume(struct device *dev)
277{
278	struct platform_device *pdev = to_platform_device(dev);
279	struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
280	struct input_dev *input = kscandat->input;
281	int error;
282
283	guard(mutex)(&input->mutex);
284
285	if (input_device_enabled(input)) {
286		/* Enable clock and clear IRQ */
287		error = clk_prepare_enable(kscandat->clk);
288		if (error)
289			return error;
290
291		writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
292	}
293
294	return 0;
295}
296
297static DEFINE_SIMPLE_DEV_PM_OPS(lpc32xx_kscan_pm_ops, lpc32xx_kscan_suspend,
298				lpc32xx_kscan_resume);
299
300static const struct of_device_id lpc32xx_kscan_match[] = {
301	{ .compatible = "nxp,lpc3220-key" },
302	{},
303};
304MODULE_DEVICE_TABLE(of, lpc32xx_kscan_match);
305
306static 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
315module_platform_driver(lpc32xx_kscan_driver);
316
317MODULE_LICENSE("GPL");
318MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>");
319MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
320MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");