1/*
2 * Copyright (C) 2014 Broadcom Corporation
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation version 2.
7 *
8 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
9 * kind, whether express or implied; without even the implied warranty
10 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11 * GNU General Public License for more details.
12 */
13
14#include <linux/bitops.h>
15#include <linux/clk.h>
16#include <linux/gfp.h>
17#include <linux/io.h>
18#include <linux/input.h>
19#include <linux/input/matrix_keypad.h>
20#include <linux/interrupt.h>
21#include <linux/module.h>
22#include <linux/of.h>
23#include <linux/platform_device.h>
24#include <linux/stddef.h>
25#include <linux/types.h>
26
27#define DEFAULT_CLK_HZ			31250
28#define MAX_ROWS			8
29#define MAX_COLS			8
30
31/* Register/field definitions */
32#define KPCR_OFFSET			0x00000080
33#define KPCR_MODE			0x00000002
34#define KPCR_MODE_SHIFT			1
35#define KPCR_MODE_MASK			1
36#define KPCR_ENABLE			0x00000001
37#define KPCR_STATUSFILTERENABLE		0x00008000
38#define KPCR_STATUSFILTERTYPE_SHIFT	12
39#define KPCR_COLFILTERENABLE		0x00000800
40#define KPCR_COLFILTERTYPE_SHIFT	8
41#define KPCR_ROWWIDTH_SHIFT		20
42#define KPCR_COLUMNWIDTH_SHIFT		16
43
44#define KPIOR_OFFSET			0x00000084
45#define KPIOR_ROWOCONTRL_SHIFT		24
46#define KPIOR_ROWOCONTRL_MASK		0xFF000000
47#define KPIOR_COLUMNOCONTRL_SHIFT	16
48#define KPIOR_COLUMNOCONTRL_MASK	0x00FF0000
49#define KPIOR_COLUMN_IO_DATA_SHIFT	0
50
51#define KPEMR0_OFFSET			0x00000090
52#define KPEMR1_OFFSET			0x00000094
53#define KPEMR2_OFFSET			0x00000098
54#define KPEMR3_OFFSET			0x0000009C
55#define KPEMR_EDGETYPE_BOTH		3
56
57#define KPSSR0_OFFSET			0x000000A0
58#define KPSSR1_OFFSET			0x000000A4
59#define KPSSRN_OFFSET(reg_n)		(KPSSR0_OFFSET + 4 * (reg_n))
60#define KPIMR0_OFFSET			0x000000B0
61#define KPIMR1_OFFSET			0x000000B4
62#define KPICR0_OFFSET			0x000000B8
63#define KPICR1_OFFSET			0x000000BC
64#define KPICRN_OFFSET(reg_n)		(KPICR0_OFFSET + 4 * (reg_n))
65#define KPISR0_OFFSET			0x000000C0
66#define KPISR1_OFFSET			0x000000C4
67
68#define KPCR_STATUSFILTERTYPE_MAX	7
69#define KPCR_COLFILTERTYPE_MAX		7
70
71/* Macros to determine the row/column from a bit that is set in SSR0/1. */
72#define BIT_TO_ROW_SSRN(bit_nr, reg_n)	(((bit_nr) >> 3) + 4 * (reg_n))
73#define BIT_TO_COL(bit_nr)		((bit_nr) % 8)
74
75/* Structure representing various run-time entities */
76struct bcm_kp {
77	void __iomem *base;
78	int irq;
79	struct clk *clk;
80	struct input_dev *input_dev;
81	unsigned long last_state[2];
82	unsigned int n_rows;
83	unsigned int n_cols;
84	u32 kpcr;
85	u32 kpior;
86	u32 kpemr;
87	u32 imr0_val;
88	u32 imr1_val;
89};
90
91/*
92 * Returns the keycode from the input device keymap given the row and
93 * column.
94 */
95static int bcm_kp_get_keycode(struct bcm_kp *kp, int row, int col)
96{
97	unsigned int row_shift = get_count_order(kp->n_cols);
98	unsigned short *keymap = kp->input_dev->keycode;
99
100	return keymap[MATRIX_SCAN_CODE(row, col, row_shift)];
101}
102
103static void bcm_kp_report_keys(struct bcm_kp *kp, int reg_num, int pull_mode)
104{
105	unsigned long state, change;
106	int bit_nr;
107	int key_press;
108	int row, col;
109	unsigned int keycode;
110
111	/* Clear interrupts */
112	writel(0xFFFFFFFF, kp->base + KPICRN_OFFSET(reg_num));
113
114	state = readl(kp->base + KPSSRN_OFFSET(reg_num));
115	change = kp->last_state[reg_num] ^ state;
116	kp->last_state[reg_num] = state;
117
118	for_each_set_bit(bit_nr, &change, BITS_PER_LONG) {
119		key_press = state & BIT(bit_nr);
120		/* The meaning of SSR register depends on pull mode. */
121		key_press = pull_mode ? !key_press : key_press;
122		row = BIT_TO_ROW_SSRN(bit_nr, reg_num);
123		col = BIT_TO_COL(bit_nr);
124		keycode = bcm_kp_get_keycode(kp, row, col);
125		input_report_key(kp->input_dev, keycode, key_press);
126	}
127}
128
129static irqreturn_t bcm_kp_isr_thread(int irq, void *dev_id)
130{
131	struct bcm_kp *kp = dev_id;
132	int pull_mode = (kp->kpcr >> KPCR_MODE_SHIFT) & KPCR_MODE_MASK;
133	int reg_num;
134
135	for (reg_num = 0; reg_num <= 1; reg_num++)
136		bcm_kp_report_keys(kp, reg_num, pull_mode);
137
138	input_sync(kp->input_dev);
139
140	return IRQ_HANDLED;
141}
142
143static int bcm_kp_start(struct bcm_kp *kp)
144{
145	int error;
146
147	if (kp->clk) {
148		error = clk_prepare_enable(kp->clk);
149		if (error)
150			return error;
151	}
152
153	writel(kp->kpior, kp->base + KPIOR_OFFSET);
154
155	writel(kp->imr0_val, kp->base + KPIMR0_OFFSET);
156	writel(kp->imr1_val, kp->base + KPIMR1_OFFSET);
157
158	writel(kp->kpemr, kp->base + KPEMR0_OFFSET);
159	writel(kp->kpemr, kp->base + KPEMR1_OFFSET);
160	writel(kp->kpemr, kp->base + KPEMR2_OFFSET);
161	writel(kp->kpemr, kp->base + KPEMR3_OFFSET);
162
163	writel(0xFFFFFFFF, kp->base + KPICR0_OFFSET);
164	writel(0xFFFFFFFF, kp->base + KPICR1_OFFSET);
165
166	kp->last_state[0] = readl(kp->base + KPSSR0_OFFSET);
167	kp->last_state[0] = readl(kp->base + KPSSR1_OFFSET);
168
169	writel(kp->kpcr | KPCR_ENABLE, kp->base + KPCR_OFFSET);
170
171	return 0;
172}
173
174static void bcm_kp_stop(const struct bcm_kp *kp)
175{
176	u32 val;
177
178	val = readl(kp->base + KPCR_OFFSET);
179	val &= ~KPCR_ENABLE;
180	writel(0, kp->base + KPCR_OFFSET);
181	writel(0, kp->base + KPIMR0_OFFSET);
182	writel(0, kp->base + KPIMR1_OFFSET);
183	writel(0xFFFFFFFF, kp->base + KPICR0_OFFSET);
184	writel(0xFFFFFFFF, kp->base + KPICR1_OFFSET);
185
186	if (kp->clk)
187		clk_disable_unprepare(kp->clk);
188}
189
190static int bcm_kp_open(struct input_dev *dev)
191{
192	struct bcm_kp *kp = input_get_drvdata(dev);
193
194	return bcm_kp_start(kp);
195}
196
197static void bcm_kp_close(struct input_dev *dev)
198{
199	struct bcm_kp *kp = input_get_drvdata(dev);
200
201	bcm_kp_stop(kp);
202}
203
204static int bcm_kp_matrix_key_parse_dt(struct bcm_kp *kp)
205{
206	struct device *dev = kp->input_dev->dev.parent;
207	struct device_node *np = dev->of_node;
208	int error;
209	unsigned int dt_val;
210	unsigned int i;
211	unsigned int num_rows, col_mask, rows_set;
212
213	/* Initialize the KPCR Keypad Configuration Register */
214	kp->kpcr = KPCR_STATUSFILTERENABLE | KPCR_COLFILTERENABLE;
215
216	error = matrix_keypad_parse_of_params(dev, &kp->n_rows, &kp->n_cols);
217	if (error) {
218		dev_err(dev, "failed to parse kp params\n");
219		return error;
220	}
221
222	/* Set row width for the ASIC block. */
223	kp->kpcr |= (kp->n_rows - 1) << KPCR_ROWWIDTH_SHIFT;
224
225	/* Set column width for the ASIC block. */
226	kp->kpcr |= (kp->n_cols - 1) << KPCR_COLUMNWIDTH_SHIFT;
227
228	/* Configure the IMR registers */
229
230	/*
231	 * IMR registers contain interrupt enable bits for 8x8 matrix
232	 * IMR0 register format: <row3> <row2> <row1> <row0>
233	 * IMR1 register format: <row7> <row6> <row5> <row4>
234	 */
235	col_mask = (1 << (kp->n_cols)) - 1;
236	num_rows = kp->n_rows;
237
238	/* Set column bits in rows 0 to 3 in IMR0 */
239	kp->imr0_val = col_mask;
240
241	rows_set = 1;
242	while (--num_rows && rows_set++ < 4)
243		kp->imr0_val |= kp->imr0_val << MAX_COLS;
244
245	/* Set column bits in rows 4 to 7 in IMR1 */
246	kp->imr1_val = 0;
247	if (num_rows) {
248		kp->imr1_val = col_mask;
249		while (--num_rows)
250			kp->imr1_val |= kp->imr1_val << MAX_COLS;
251	}
252
253	/* Initialize the KPEMR Keypress Edge Mode Registers */
254	/* Trigger on both edges */
255	kp->kpemr = 0;
256	for (i = 0; i <= 30; i += 2)
257		kp->kpemr |= (KPEMR_EDGETYPE_BOTH << i);
258
259	/*
260	 * Obtain the Status filter debounce value and verify against the
261	 * possible values specified in the DT binding.
262	 */
263	of_property_read_u32(np, "status-debounce-filter-period", &dt_val);
264
265	if (dt_val > KPCR_STATUSFILTERTYPE_MAX) {
266		dev_err(dev, "Invalid Status filter debounce value %d\n",
267			dt_val);
268		return -EINVAL;
269	}
270
271	kp->kpcr |= dt_val << KPCR_STATUSFILTERTYPE_SHIFT;
272
273	/*
274	 * Obtain the Column filter debounce value and verify against the
275	 * possible values specified in the DT binding.
276	 */
277	of_property_read_u32(np, "col-debounce-filter-period", &dt_val);
278
279	if (dt_val > KPCR_COLFILTERTYPE_MAX) {
280		dev_err(dev, "Invalid Column filter debounce value %d\n",
281			dt_val);
282		return -EINVAL;
283	}
284
285	kp->kpcr |= dt_val << KPCR_COLFILTERTYPE_SHIFT;
286
287	/*
288	 * Determine between the row and column,
289	 * which should be configured as output.
290	 */
291	if (of_property_read_bool(np, "row-output-enabled")) {
292		/*
293		* Set RowOContrl or ColumnOContrl in KPIOR
294		* to the number of pins to drive as outputs
295		*/
296		kp->kpior = ((1 << kp->n_rows) - 1) <<
297				KPIOR_ROWOCONTRL_SHIFT;
298	} else {
299		kp->kpior = ((1 << kp->n_cols) - 1) <<
300				KPIOR_COLUMNOCONTRL_SHIFT;
301	}
302
303	/*
304	 * Determine if the scan pull up needs to be enabled
305	 */
306	if (of_property_read_bool(np, "pull-up-enabled"))
307		kp->kpcr |= KPCR_MODE;
308
309	dev_dbg(dev, "n_rows=%d n_col=%d kpcr=%x kpior=%x kpemr=%x\n",
310		kp->n_rows, kp->n_cols,
311		kp->kpcr, kp->kpior, kp->kpemr);
312
313	return 0;
314}
315
316
317static int bcm_kp_probe(struct platform_device *pdev)
318{
319	struct bcm_kp *kp;
320	struct input_dev *input_dev;
321	struct resource *res;
322	int error;
323
324	kp = devm_kzalloc(&pdev->dev, sizeof(*kp), GFP_KERNEL);
325	if (!kp)
326		return -ENOMEM;
327
328	input_dev = devm_input_allocate_device(&pdev->dev);
329	if (!input_dev) {
330		dev_err(&pdev->dev, "failed to allocate the input device\n");
331		return -ENOMEM;
332	}
333
334	__set_bit(EV_KEY, input_dev->evbit);
335
336	/* Enable auto repeat feature of Linux input subsystem */
337	if (of_property_read_bool(pdev->dev.of_node, "autorepeat"))
338		__set_bit(EV_REP, input_dev->evbit);
339
340	input_dev->name = pdev->name;
341	input_dev->phys = "keypad/input0";
342	input_dev->dev.parent = &pdev->dev;
343	input_dev->open = bcm_kp_open;
344	input_dev->close = bcm_kp_close;
345
346	input_dev->id.bustype = BUS_HOST;
347	input_dev->id.vendor = 0x0001;
348	input_dev->id.product = 0x0001;
349	input_dev->id.version = 0x0100;
350
351	input_set_drvdata(input_dev, kp);
352
353	kp->input_dev = input_dev;
354
355	platform_set_drvdata(pdev, kp);
356
357	error = bcm_kp_matrix_key_parse_dt(kp);
358	if (error)
359		return error;
360
361	error = matrix_keypad_build_keymap(NULL, NULL,
362					   kp->n_rows, kp->n_cols,
363					   NULL, input_dev);
364	if (error) {
365		dev_err(&pdev->dev, "failed to build keymap\n");
366		return error;
367	}
368
369	/* Get the KEYPAD base address */
370	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
371	if (!res) {
372		dev_err(&pdev->dev, "Missing keypad base address resource\n");
373		return -ENODEV;
374	}
375
376	kp->base = devm_ioremap_resource(&pdev->dev, res);
377	if (IS_ERR(kp->base))
378		return PTR_ERR(kp->base);
379
380	/* Enable clock */
381	kp->clk = devm_clk_get(&pdev->dev, "peri_clk");
382	if (IS_ERR(kp->clk)) {
383		error = PTR_ERR(kp->clk);
384		if (error != -ENOENT) {
385			if (error != -EPROBE_DEFER)
386				dev_err(&pdev->dev, "Failed to get clock\n");
387			return error;
388		}
389		dev_dbg(&pdev->dev,
390			"No clock specified. Assuming it's enabled\n");
391		kp->clk = NULL;
392	} else {
393		unsigned int desired_rate;
394		long actual_rate;
395
396		error = of_property_read_u32(pdev->dev.of_node,
397					     "clock-frequency", &desired_rate);
398		if (error < 0)
399			desired_rate = DEFAULT_CLK_HZ;
400
401		actual_rate = clk_round_rate(kp->clk, desired_rate);
402		if (actual_rate <= 0)
403			return -EINVAL;
404
405		error = clk_set_rate(kp->clk, actual_rate);
406		if (error)
407			return error;
408
409		error = clk_prepare_enable(kp->clk);
410		if (error)
411			return error;
412	}
413
414	/* Put the kp into a known sane state */
415	bcm_kp_stop(kp);
416
417	kp->irq = platform_get_irq(pdev, 0);
418	if (kp->irq < 0) {
419		dev_err(&pdev->dev, "no IRQ specified\n");
420		return -EINVAL;
421	}
422
423	error = devm_request_threaded_irq(&pdev->dev, kp->irq,
424					  NULL, bcm_kp_isr_thread,
425					  IRQF_ONESHOT, pdev->name, kp);
426	if (error) {
427		dev_err(&pdev->dev, "failed to request IRQ\n");
428		return error;
429	}
430
431	error = input_register_device(input_dev);
432	if (error) {
433		dev_err(&pdev->dev, "failed to register input device\n");
434		return error;
435	}
436
437	return 0;
438}
439
440static const struct of_device_id bcm_kp_of_match[] = {
441	{ .compatible = "brcm,bcm-keypad" },
442	{ },
443};
444MODULE_DEVICE_TABLE(of, bcm_kp_of_match);
445
446static struct platform_driver bcm_kp_device_driver = {
447	.probe		= bcm_kp_probe,
448	.driver		= {
449		.name	= "bcm-keypad",
450		.of_match_table = of_match_ptr(bcm_kp_of_match),
451	}
452};
453
454module_platform_driver(bcm_kp_device_driver);
455
456MODULE_AUTHOR("Broadcom Corporation");
457MODULE_DESCRIPTION("BCM Keypad Driver");
458MODULE_LICENSE("GPL v2");
459