twl4030_keypad.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * twl4030_keypad.c - driver for 8x8 keypad controller in twl4030 chips
  4 *
  5 * Copyright (C) 2007 Texas Instruments, Inc.
  6 * Copyright (C) 2008 Nokia Corporation
  7 *
  8 * Code re-written for 2430SDP by:
  9 * Syed Mohammed Khasim <x0khasim@ti.com>
 10 *
 11 * Initial Code:
 12 * Manjunatha G K <manjugk@ti.com>
 13 */
 14
 15#include <linux/kernel.h>
 16#include <linux/module.h>
 17#include <linux/interrupt.h>
 18#include <linux/input.h>
 19#include <linux/platform_device.h>
 20#include <linux/mfd/twl.h>
 21#include <linux/slab.h>
 22#include <linux/of.h>
 23
 24/*
 25 * The TWL4030 family chips include a keypad controller that supports
 26 * up to an 8x8 switch matrix.  The controller can issue system wakeup
 27 * events, since it uses only the always-on 32KiHz oscillator, and has
 28 * an internal state machine that decodes pressed keys, including
 29 * multi-key combinations.
 30 *
 31 * See the TPS65950 documentation; that's the general availability
 32 * version of the TWL5030 second generation part.
 33 */
 34#define TWL4030_MAX_ROWS	8	/* TWL4030 hard limit */
 35#define TWL4030_MAX_COLS	8
 36/*
 37 * Note that we add space for an extra column so that we can handle
 38 * row lines connected to the gnd (see twl4030_col_xlate()).
 39 */
 40#define TWL4030_ROW_SHIFT	4
 41#define TWL4030_KEYMAP_SIZE	(TWL4030_MAX_ROWS << TWL4030_ROW_SHIFT)
 42
 43struct twl4030_keypad {
 44	unsigned short	keymap[TWL4030_KEYMAP_SIZE];
 45	u16		kp_state[TWL4030_MAX_ROWS];
 46	unsigned int	n_rows;
 47	unsigned int	n_cols;
 48	int		irq;
 49
 50	struct device *dbg_dev;
 51	struct input_dev *input;
 52};
 53
 54/*----------------------------------------------------------------------*/
 55
 56/* arbitrary prescaler value 0..7 */
 57#define PTV_PRESCALER			4
 58
 59/* Register Offsets */
 60#define KEYP_CTRL			0x00
 61#define KEYP_DEB			0x01
 62#define KEYP_LONG_KEY			0x02
 63#define KEYP_LK_PTV			0x03
 64#define KEYP_TIMEOUT_L			0x04
 65#define KEYP_TIMEOUT_H			0x05
 66#define KEYP_KBC			0x06
 67#define KEYP_KBR			0x07
 68#define KEYP_SMS			0x08
 69#define KEYP_FULL_CODE_7_0		0x09	/* row 0 column status */
 70#define KEYP_FULL_CODE_15_8		0x0a	/* ... row 1 ... */
 71#define KEYP_FULL_CODE_23_16		0x0b
 72#define KEYP_FULL_CODE_31_24		0x0c
 73#define KEYP_FULL_CODE_39_32		0x0d
 74#define KEYP_FULL_CODE_47_40		0x0e
 75#define KEYP_FULL_CODE_55_48		0x0f
 76#define KEYP_FULL_CODE_63_56		0x10
 77#define KEYP_ISR1			0x11
 78#define KEYP_IMR1			0x12
 79#define KEYP_ISR2			0x13
 80#define KEYP_IMR2			0x14
 81#define KEYP_SIR			0x15
 82#define KEYP_EDR			0x16	/* edge triggers */
 83#define KEYP_SIH_CTRL			0x17
 84
 85/* KEYP_CTRL_REG Fields */
 86#define KEYP_CTRL_SOFT_NRST		BIT(0)
 87#define KEYP_CTRL_SOFTMODEN		BIT(1)
 88#define KEYP_CTRL_LK_EN			BIT(2)
 89#define KEYP_CTRL_TOE_EN		BIT(3)
 90#define KEYP_CTRL_TOLE_EN		BIT(4)
 91#define KEYP_CTRL_RP_EN			BIT(5)
 92#define KEYP_CTRL_KBD_ON		BIT(6)
 93
 94/* KEYP_DEB, KEYP_LONG_KEY, KEYP_TIMEOUT_x*/
 95#define KEYP_PERIOD_US(t, prescale)	((t) / (31 << ((prescale) + 1)) - 1)
 96
 97/* KEYP_LK_PTV_REG Fields */
 98#define KEYP_LK_PTV_PTV_SHIFT		5
 99
100/* KEYP_{IMR,ISR,SIR} Fields */
101#define KEYP_IMR1_MIS			BIT(3)
102#define KEYP_IMR1_TO			BIT(2)
103#define KEYP_IMR1_LK			BIT(1)
104#define KEYP_IMR1_KP			BIT(0)
105
106/* KEYP_EDR Fields */
107#define KEYP_EDR_KP_FALLING		0x01
108#define KEYP_EDR_KP_RISING		0x02
109#define KEYP_EDR_KP_BOTH		0x03
110#define KEYP_EDR_LK_FALLING		0x04
111#define KEYP_EDR_LK_RISING		0x08
112#define KEYP_EDR_TO_FALLING		0x10
113#define KEYP_EDR_TO_RISING		0x20
114#define KEYP_EDR_MIS_FALLING		0x40
115#define KEYP_EDR_MIS_RISING		0x80
116
117
118/*----------------------------------------------------------------------*/
119
120static int twl4030_kpread(struct twl4030_keypad *kp,
121		u8 *data, u32 reg, u8 num_bytes)
122{
123	int ret = twl_i2c_read(TWL4030_MODULE_KEYPAD, data, reg, num_bytes);
124
125	if (ret < 0)
126		dev_warn(kp->dbg_dev,
127			"Couldn't read TWL4030: %X - ret %d[%x]\n",
128			 reg, ret, ret);
129
130	return ret;
131}
132
133static int twl4030_kpwrite_u8(struct twl4030_keypad *kp, u8 data, u32 reg)
134{
135	int ret = twl_i2c_write_u8(TWL4030_MODULE_KEYPAD, data, reg);
136
137	if (ret < 0)
138		dev_warn(kp->dbg_dev,
139			"Could not write TWL4030: %X - ret %d[%x]\n",
140			 reg, ret, ret);
141
142	return ret;
143}
144
145static inline u16 twl4030_col_xlate(struct twl4030_keypad *kp, u8 col)
146{
147	/*
148	 * If all bits in a row are active for all columns then
149	 * we have that row line connected to gnd. Mark this
150	 * key on as if it was on matrix position n_cols (i.e.
151	 * one higher than the size of the matrix).
152	 */
153	if (col == 0xFF)
154		return 1 << kp->n_cols;
155	else
156		return col & ((1 << kp->n_cols) - 1);
157}
158
159static int twl4030_read_kp_matrix_state(struct twl4030_keypad *kp, u16 *state)
160{
161	u8 new_state[TWL4030_MAX_ROWS];
162	int row;
163	int ret = twl4030_kpread(kp, new_state,
164				 KEYP_FULL_CODE_7_0, kp->n_rows);
165	if (ret >= 0)
166		for (row = 0; row < kp->n_rows; row++)
167			state[row] = twl4030_col_xlate(kp, new_state[row]);
168
169	return ret;
170}
171
172static bool twl4030_is_in_ghost_state(struct twl4030_keypad *kp, u16 *key_state)
173{
174	int i;
175	u16 check = 0;
176
177	for (i = 0; i < kp->n_rows; i++) {
178		u16 col = key_state[i];
179
180		if ((col & check) && hweight16(col) > 1)
181			return true;
182
183		check |= col;
184	}
185
186	return false;
187}
188
189static void twl4030_kp_scan(struct twl4030_keypad *kp, bool release_all)
190{
191	struct input_dev *input = kp->input;
192	u16 new_state[TWL4030_MAX_ROWS];
193	int col, row;
194
195	if (release_all) {
196		memset(new_state, 0, sizeof(new_state));
197	} else {
198		/* check for any changes */
199		int ret = twl4030_read_kp_matrix_state(kp, new_state);
200
201		if (ret < 0)	/* panic ... */
202			return;
203
204		if (twl4030_is_in_ghost_state(kp, new_state))
205			return;
206	}
207
208	/* check for changes and print those */
209	for (row = 0; row < kp->n_rows; row++) {
210		int changed = new_state[row] ^ kp->kp_state[row];
211
212		if (!changed)
213			continue;
214
215		/* Extra column handles "all gnd" rows */
216		for (col = 0; col < kp->n_cols + 1; col++) {
217			int code;
218
219			if (!(changed & (1 << col)))
220				continue;
221
222			dev_dbg(kp->dbg_dev, "key [%d:%d] %s\n", row, col,
223				(new_state[row] & (1 << col)) ?
224				"press" : "release");
225
226			code = MATRIX_SCAN_CODE(row, col, TWL4030_ROW_SHIFT);
227			input_event(input, EV_MSC, MSC_SCAN, code);
228			input_report_key(input, kp->keymap[code],
229					 new_state[row] & (1 << col));
230		}
231		kp->kp_state[row] = new_state[row];
232	}
233	input_sync(input);
234}
235
236/*
237 * Keypad interrupt handler
238 */
239static irqreturn_t do_kp_irq(int irq, void *_kp)
240{
241	struct twl4030_keypad *kp = _kp;
242	u8 reg;
243	int ret;
244
245	/* Read & Clear TWL4030 pending interrupt */
246	ret = twl4030_kpread(kp, &reg, KEYP_ISR1, 1);
247
248	/*
249	 * Release all keys if I2C has gone bad or
250	 * the KEYP has gone to idle state.
251	 */
252	if (ret >= 0 && (reg & KEYP_IMR1_KP))
253		twl4030_kp_scan(kp, false);
254	else
255		twl4030_kp_scan(kp, true);
256
257	return IRQ_HANDLED;
258}
259
260static int twl4030_kp_program(struct twl4030_keypad *kp)
261{
262	u8 reg;
263	int i;
264
265	/* Enable controller, with hardware decoding but not autorepeat */
266	reg = KEYP_CTRL_SOFT_NRST | KEYP_CTRL_SOFTMODEN
267		| KEYP_CTRL_TOE_EN | KEYP_CTRL_KBD_ON;
268	if (twl4030_kpwrite_u8(kp, reg, KEYP_CTRL) < 0)
269		return -EIO;
270
271	/*
272	 * NOTE: we could use sih_setup() here to package keypad
273	 * event sources as four different IRQs ... but we don't.
274	 */
275
276	/* Enable TO rising and KP rising and falling edge detection */
277	reg = KEYP_EDR_KP_BOTH | KEYP_EDR_TO_RISING;
278	if (twl4030_kpwrite_u8(kp, reg, KEYP_EDR) < 0)
279		return -EIO;
280
281	/* Set PTV prescaler Field */
282	reg = (PTV_PRESCALER << KEYP_LK_PTV_PTV_SHIFT);
283	if (twl4030_kpwrite_u8(kp, reg, KEYP_LK_PTV) < 0)
284		return -EIO;
285
286	/* Set key debounce time to 20 ms */
287	i = KEYP_PERIOD_US(20000, PTV_PRESCALER);
288	if (twl4030_kpwrite_u8(kp, i, KEYP_DEB) < 0)
289		return -EIO;
290
291	/* Set timeout period to 200 ms */
292	i = KEYP_PERIOD_US(200000, PTV_PRESCALER);
293	if (twl4030_kpwrite_u8(kp, (i & 0xFF), KEYP_TIMEOUT_L) < 0)
294		return -EIO;
295
296	if (twl4030_kpwrite_u8(kp, (i >> 8), KEYP_TIMEOUT_H) < 0)
297		return -EIO;
298
299	/*
300	 * Enable Clear-on-Read; disable remembering events that fire
301	 * after the IRQ but before our handler acks (reads) them.
302	 */
303	reg = TWL4030_SIH_CTRL_COR_MASK | TWL4030_SIH_CTRL_PENDDIS_MASK;
304	if (twl4030_kpwrite_u8(kp, reg, KEYP_SIH_CTRL) < 0)
305		return -EIO;
306
307	/* initialize key state; irqs update it from here on */
308	if (twl4030_read_kp_matrix_state(kp, kp->kp_state) < 0)
309		return -EIO;
310
311	return 0;
312}
313
314/*
315 * Registers keypad device with input subsystem
316 * and configures TWL4030 keypad registers
317 */
318static int twl4030_kp_probe(struct platform_device *pdev)
319{
320	struct twl4030_keypad *kp;
321	struct input_dev *input;
322	u8 reg;
323	int error;
324
325	kp = devm_kzalloc(&pdev->dev, sizeof(*kp), GFP_KERNEL);
326	if (!kp)
327		return -ENOMEM;
328
329	input = devm_input_allocate_device(&pdev->dev);
330	if (!input)
331		return -ENOMEM;
332
333	/* get the debug device */
334	kp->dbg_dev		= &pdev->dev;
335	kp->input		= input;
336
337	/* setup input device */
338	input->name		= "TWL4030 Keypad";
339	input->phys		= "twl4030_keypad/input0";
340
341	input->id.bustype	= BUS_HOST;
342	input->id.vendor	= 0x0001;
343	input->id.product	= 0x0001;
344	input->id.version	= 0x0003;
345
346	error = matrix_keypad_parse_properties(&pdev->dev,
347					       &kp->n_rows, &kp->n_cols);
348	if (error)
349		return error;
350
351	if (kp->n_rows > TWL4030_MAX_ROWS || kp->n_cols > TWL4030_MAX_COLS) {
352		dev_err(&pdev->dev,
353			"Invalid rows/cols amount specified in platform/devicetree data\n");
354		return -EINVAL;
355	}
356
357	kp->irq = platform_get_irq(pdev, 0);
358	if (kp->irq < 0)
359		return kp->irq;
360
361	error = matrix_keypad_build_keymap(NULL, NULL,
362					   TWL4030_MAX_ROWS,
363					   1 << TWL4030_ROW_SHIFT,
364					   kp->keymap, input);
365	if (error) {
366		dev_err(kp->dbg_dev, "Failed to build keymap\n");
367		return error;
368	}
369
370	input_set_capability(input, EV_MSC, MSC_SCAN);
371	__set_bit(EV_REP, input->evbit);
372
373	error = input_register_device(input);
374	if (error) {
375		dev_err(kp->dbg_dev,
376			"Unable to register twl4030 keypad device\n");
377		return error;
378	}
379
380	error = twl4030_kp_program(kp);
381	if (error)
382		return error;
383
384	/*
385	 * This ISR will always execute in kernel thread context because of
386	 * the need to access the TWL4030 over the I2C bus.
387	 *
388	 * NOTE:  we assume this host is wired to TWL4040 INT1, not INT2 ...
389	 */
390	error = devm_request_threaded_irq(&pdev->dev, kp->irq, NULL, do_kp_irq,
391					  0, pdev->name, kp);
392	if (error) {
393		dev_info(kp->dbg_dev, "request_irq failed for irq no=%d: %d\n",
394			kp->irq, error);
395		return error;
396	}
397
398	/* Enable KP and TO interrupts now. */
399	reg = (u8) ~(KEYP_IMR1_KP | KEYP_IMR1_TO);
400	if (twl4030_kpwrite_u8(kp, reg, KEYP_IMR1)) {
401		/* mask all events - we don't care about the result */
402		(void) twl4030_kpwrite_u8(kp, 0xff, KEYP_IMR1);
403		return -EIO;
404	}
405
406	return 0;
407}
408
409#ifdef CONFIG_OF
410static const struct of_device_id twl4030_keypad_dt_match_table[] = {
411	{ .compatible = "ti,twl4030-keypad" },
412	{},
413};
414MODULE_DEVICE_TABLE(of, twl4030_keypad_dt_match_table);
415#endif
416
417/*
418 * NOTE: twl4030 are multi-function devices connected via I2C.
419 * So this device is a child of an I2C parent, thus it needs to
420 * support unplug/replug (which most platform devices don't).
421 */
422
423static struct platform_driver twl4030_kp_driver = {
424	.probe		= twl4030_kp_probe,
425	.driver		= {
426		.name	= "twl4030_keypad",
427		.of_match_table = of_match_ptr(twl4030_keypad_dt_match_table),
428	},
429};
430module_platform_driver(twl4030_kp_driver);
431
432MODULE_AUTHOR("Texas Instruments");
433MODULE_DESCRIPTION("TWL4030 Keypad Driver");
434MODULE_LICENSE("GPL");
435MODULE_ALIAS("platform:twl4030_keypad");