1// SPDX-License-Identifier: GPL-2.0+
2/*
3 *  (C) Copyright 2011
4 *  NVIDIA Corporation <www.nvidia.com>
5 */
6
7#include <dm.h>
8#include <fdtdec.h>
9#include <input.h>
10#include <keyboard.h>
11#include <key_matrix.h>
12#include <log.h>
13#include <stdio_dev.h>
14#include <tegra-kbc.h>
15#include <time.h>
16#include <asm/io.h>
17#include <asm/arch/clock.h>
18#include <asm/arch/funcmux.h>
19#include <asm/arch-tegra/timer.h>
20#include <linux/delay.h>
21#include <linux/input.h>
22
23enum {
24	KBC_MAX_GPIO		= 24,
25	KBC_MAX_KPENT		= 8,	/* size of keypress entry queue */
26};
27
28#define KBC_FIFO_TH_CNT_SHIFT		14
29#define KBC_DEBOUNCE_CNT_SHIFT		4
30#define KBC_CONTROL_FIFO_CNT_INT_EN	(1 << 3)
31#define KBC_CONTROL_KBC_EN		(1 << 0)
32#define KBC_INT_FIFO_CNT_INT_STATUS	(1 << 2)
33#define KBC_KPENT_VALID			(1 << 7)
34#define KBC_ST_STATUS			(1 << 3)
35
36enum {
37	KBC_DEBOUNCE_COUNT	= 2,
38	KBC_REPEAT_RATE_MS	= 30,
39	KBC_REPEAT_DELAY_MS	= 240,
40	KBC_CLOCK_KHZ		= 32,	/* Keyboard uses a 32KHz clock */
41};
42
43/* keyboard controller config and state */
44struct tegra_kbd_priv {
45	struct input_config *input;	/* The input layer */
46	struct key_matrix matrix;	/* The key matrix layer */
47
48	struct kbc_tegra *kbc;		/* tegra keyboard controller */
49	unsigned char inited;		/* 1 if keyboard has been inited */
50	unsigned char first_scan;	/* 1 if this is our first key scan */
51
52	/*
53	 * After init we must wait a short time before polling the keyboard.
54	 * This gives the tegra keyboard controller time to react after reset
55	 * and lets us grab keys pressed during reset.
56	 */
57	unsigned int init_dly_ms;	/* Delay before we can read keyboard */
58	unsigned int start_time_ms;	/* Time that we inited (in ms) */
59	unsigned int last_poll_ms;	/* Time we should last polled */
60	unsigned int next_repeat_ms;	/* Next time we repeat a key */
61};
62
63/**
64 * reads the keyboard fifo for current keypresses
65 *
66 * @param priv		Keyboard private data
67 * @param fifo		Place to put fifo results
68 * @param max_keycodes	Maximum number of key codes to put in the fifo
69 * Return: number of items put into fifo
70 */
71static int tegra_kbc_find_keys(struct tegra_kbd_priv *priv, int *fifo,
72			       int max_keycodes)
73{
74	struct key_matrix_key keys[KBC_MAX_KPENT], *key;
75	u32 kp_ent = 0;
76	int i;
77
78	for (key = keys, i = 0; i < KBC_MAX_KPENT; i++, key++) {
79		/* Get next word */
80		if (!(i & 3))
81			kp_ent = readl(&priv->kbc->kp_ent[i / 4]);
82
83		key->valid = (kp_ent & KBC_KPENT_VALID) != 0;
84		key->row = (kp_ent >> 3) & 0xf;
85		key->col = kp_ent & 0x7;
86
87		/* Shift to get next entry */
88		kp_ent >>= 8;
89	}
90	return key_matrix_decode(&priv->matrix, keys, KBC_MAX_KPENT, fifo,
91				 max_keycodes);
92}
93
94/**
95 * Process all the keypress sequences in fifo and send key codes
96 *
97 * The fifo contains zero or more keypress sets. Each set
98 * consists of from 1-8 keycodes, representing the keycodes which
99 * were simultaneously pressed during that scan.
100 *
101 * This function works through each set and generates ASCII characters
102 * for each. Not that one set may produce more than one ASCII characters -
103 * for example holding down 'd' and 'f' at the same time will generate
104 * two ASCII characters.
105 *
106 * Note: if fifo_cnt is 0, we will tell the input layer that no keys are
107 * pressed.
108 *
109 * @param priv		Keyboard private data
110 * @param fifo_cnt	Number of entries in the keyboard fifo
111 */
112static void process_fifo(struct tegra_kbd_priv *priv, int fifo_cnt)
113{
114	int fifo[KBC_MAX_KPENT];
115	int cnt = 0;
116
117	/* Always call input_send_keycodes() at least once */
118	do {
119		if (fifo_cnt)
120			cnt = tegra_kbc_find_keys(priv, fifo, KBC_MAX_KPENT);
121
122		input_send_keycodes(priv->input, fifo, cnt);
123	} while (--fifo_cnt > 0);
124}
125
126/**
127 * Check the keyboard controller and emit ASCII characters for any keys that
128 * are pressed.
129 *
130 * @param priv		Keyboard private data
131 */
132static void check_for_keys(struct tegra_kbd_priv *priv)
133{
134	int fifo_cnt;
135
136	if (!priv->first_scan &&
137	    get_timer(priv->last_poll_ms) < KBC_REPEAT_RATE_MS)
138		return;
139	priv->last_poll_ms = get_timer(0);
140	priv->first_scan = 0;
141
142	/*
143	 * Once we get here we know the keyboard has been scanned. So if there
144	 * scan waiting for us, we know that nothing is held down.
145	 */
146	fifo_cnt = (readl(&priv->kbc->interrupt) >> 4) & 0xf;
147	process_fifo(priv, fifo_cnt);
148}
149
150/**
151 * In order to detect keys pressed on boot, wait for the hardware to
152 * complete scanning the keys. This includes time to transition from
153 * Wkup mode to Continous polling mode and the repoll time. We can
154 * deduct the time that's already elapsed.
155 *
156 * @param priv		Keyboard private data
157 */
158static void kbd_wait_for_fifo_init(struct tegra_kbd_priv *priv)
159{
160	if (!priv->inited) {
161		unsigned long elapsed_time;
162		long delay_ms;
163
164		elapsed_time = get_timer(priv->start_time_ms);
165		delay_ms = priv->init_dly_ms - elapsed_time;
166		if (delay_ms > 0) {
167			udelay(delay_ms * 1000);
168			debug("%s: delay %ldms\n", __func__, delay_ms);
169		}
170
171		priv->inited = 1;
172	}
173}
174
175/**
176 * Check the tegra keyboard, and send any keys that are pressed.
177 *
178 * This is called by input_tstc() and input_getc() when they need more
179 * characters
180 *
181 * @param input		Input configuration
182 * Return: 1, to indicate that we have something to look at
183 */
184static int tegra_kbc_check(struct input_config *input)
185{
186	struct tegra_kbd_priv *priv = dev_get_priv(input->dev);
187
188	kbd_wait_for_fifo_init(priv);
189	check_for_keys(priv);
190
191	return 1;
192}
193
194/* configures keyboard GPIO registers to use the rows and columns */
195static void config_kbc_gpio(struct tegra_kbd_priv *priv, struct kbc_tegra *kbc)
196{
197	int i;
198
199	for (i = 0; i < KBC_MAX_GPIO; i++) {
200		u32 row_cfg, col_cfg;
201		u32 r_shift = 5 * (i % 6);
202		u32 c_shift = 4 * (i % 8);
203		u32 r_mask = 0x1f << r_shift;
204		u32 c_mask = 0xf << c_shift;
205		u32 r_offs = i / 6;
206		u32 c_offs = i / 8;
207
208		row_cfg = readl(&kbc->row_cfg[r_offs]);
209		col_cfg = readl(&kbc->col_cfg[c_offs]);
210
211		row_cfg &= ~r_mask;
212		col_cfg &= ~c_mask;
213
214		if (i < priv->matrix.num_rows) {
215			row_cfg |= ((i << 1) | 1) << r_shift;
216		} else {
217			col_cfg |= (((i - priv->matrix.num_rows) << 1) | 1)
218					<< c_shift;
219		}
220
221		writel(row_cfg, &kbc->row_cfg[r_offs]);
222		writel(col_cfg, &kbc->col_cfg[c_offs]);
223	}
224}
225
226/**
227 * Start up the keyboard device
228 */
229static void tegra_kbc_open(struct tegra_kbd_priv *priv)
230{
231	struct kbc_tegra *kbc = priv->kbc;
232	unsigned int scan_period;
233	u32 val;
234
235	/*
236	 * We will scan at twice the keyboard repeat rate, so that there is
237	 * always a scan ready when we check it in check_for_keys().
238	 */
239	scan_period = KBC_REPEAT_RATE_MS / 2;
240	writel(scan_period * KBC_CLOCK_KHZ, &kbc->rpt_dly);
241	writel(scan_period * KBC_CLOCK_KHZ, &kbc->init_dly);
242	/*
243	 * Before reading from the keyboard we must wait for the init_dly
244	 * plus the rpt_delay, plus 2ms for the row scan time.
245	 */
246	priv->init_dly_ms = scan_period * 2 + 2;
247
248	val = KBC_DEBOUNCE_COUNT << KBC_DEBOUNCE_CNT_SHIFT;
249	val |= 1 << KBC_FIFO_TH_CNT_SHIFT;	/* fifo interrupt threshold */
250	val |= KBC_CONTROL_KBC_EN;		/* enable */
251	writel(val, &kbc->control);
252
253	priv->start_time_ms = get_timer(0);
254	priv->last_poll_ms = get_timer(0);
255	priv->next_repeat_ms = priv->last_poll_ms;
256	priv->first_scan = 1;
257}
258
259static int tegra_kbd_start(struct udevice *dev)
260{
261	struct tegra_kbd_priv *priv = dev_get_priv(dev);
262
263	/* Set up pin mux and enable the clock */
264	funcmux_select(PERIPH_ID_KBC, FUNCMUX_DEFAULT);
265	clock_enable(PERIPH_ID_KBC);
266	config_kbc_gpio(priv, priv->kbc);
267
268	tegra_kbc_open(priv);
269	debug("%s: Tegra keyboard ready\n", __func__);
270
271	return 0;
272}
273
274/**
275 * Set up the tegra keyboard. This is called by the stdio device handler
276 *
277 * We want to do this init when the keyboard is actually used rather than
278 * at start-up, since keyboard input may not currently be selected.
279 *
280 * Once the keyboard starts there will be a period during which we must
281 * wait for the keyboard to init. We do this only when a key is first
282 * read - see kbd_wait_for_fifo_init().
283 *
284 * Return: 0 if ok, -ve on error
285 */
286static int tegra_kbd_probe(struct udevice *dev)
287{
288	struct tegra_kbd_priv *priv = dev_get_priv(dev);
289	struct keyboard_priv *uc_priv = dev_get_uclass_priv(dev);
290	struct stdio_dev *sdev = &uc_priv->sdev;
291	struct input_config *input = &uc_priv->input;
292	int ret;
293
294	priv->kbc = dev_read_addr_ptr(dev);
295	if ((fdt_addr_t)priv->kbc == FDT_ADDR_T_NONE) {
296		debug("%s: No keyboard register found\n", __func__);
297		return -EINVAL;
298	}
299	input_set_delays(input, KBC_REPEAT_DELAY_MS, KBC_REPEAT_RATE_MS);
300
301	/* Decode the keyboard matrix information (16 rows, 8 columns) */
302	ret = key_matrix_init(&priv->matrix, 16, 8, 1);
303	if (ret) {
304		debug("%s: Could not init key matrix: %d\n", __func__, ret);
305		return ret;
306	}
307	ret = key_matrix_decode_fdt(dev, &priv->matrix);
308	if (ret) {
309		debug("%s: Could not decode key matrix from fdt: %d\n",
310		      __func__, ret);
311		return ret;
312	}
313	input_add_tables(input, false);
314	if (priv->matrix.fn_keycode) {
315		ret = input_add_table(input, KEY_FN, -1,
316				      priv->matrix.fn_keycode,
317				      priv->matrix.key_count);
318		if (ret) {
319			debug("%s: input_add_table() failed\n", __func__);
320			return ret;
321		}
322	}
323
324	/* Register the device. init_tegra_keyboard() will be called soon */
325	priv->input = input;
326	input->dev = dev;
327	input->read_keys = tegra_kbc_check;
328	strcpy(sdev->name, "tegra-kbc");
329	ret = input_stdio_register(sdev);
330	if (ret) {
331		debug("%s: input_stdio_register() failed\n", __func__);
332		return ret;
333	}
334
335	return 0;
336}
337
338static const struct keyboard_ops tegra_kbd_ops = {
339	.start	= tegra_kbd_start,
340};
341
342static const struct udevice_id tegra_kbd_ids[] = {
343	{ .compatible = "nvidia,tegra20-kbc" },
344	{ }
345};
346
347U_BOOT_DRIVER(tegra_kbd) = {
348	.name	= "tegra_kbd",
349	.id	= UCLASS_KEYBOARD,
350	.of_match = tegra_kbd_ids,
351	.probe = tegra_kbd_probe,
352	.ops	= &tegra_kbd_ops,
353	.priv_auto	= sizeof(struct tegra_kbd_priv),
354};
355