xref: /openbmc/u-boot/drivers/input/tegra-kbc.c (revision 70b95ded)
1 /*
2  *  (C) Copyright 2011
3  *  NVIDIA Corporation <www.nvidia.com>
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 
8 #include <common.h>
9 #include <dm.h>
10 #include <fdtdec.h>
11 #include <input.h>
12 #include <keyboard.h>
13 #include <key_matrix.h>
14 #include <stdio_dev.h>
15 #include <tegra-kbc.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/input.h>
21 
22 DECLARE_GLOBAL_DATA_PTR;
23 
24 enum {
25 	KBC_MAX_GPIO		= 24,
26 	KBC_MAX_KPENT		= 8,	/* size of keypress entry queue */
27 };
28 
29 #define KBC_FIFO_TH_CNT_SHIFT		14
30 #define KBC_DEBOUNCE_CNT_SHIFT		4
31 #define KBC_CONTROL_FIFO_CNT_INT_EN	(1 << 3)
32 #define KBC_CONTROL_KBC_EN		(1 << 0)
33 #define KBC_INT_FIFO_CNT_INT_STATUS	(1 << 2)
34 #define KBC_KPENT_VALID			(1 << 7)
35 #define KBC_ST_STATUS			(1 << 3)
36 
37 enum {
38 	KBC_DEBOUNCE_COUNT	= 2,
39 	KBC_REPEAT_RATE_MS	= 30,
40 	KBC_REPEAT_DELAY_MS	= 240,
41 	KBC_CLOCK_KHZ		= 32,	/* Keyboard uses a 32KHz clock */
42 };
43 
44 /* keyboard controller config and state */
45 struct tegra_kbd_priv {
46 	struct input_config *input;	/* The input layer */
47 	struct key_matrix matrix;	/* The key matrix layer */
48 
49 	struct kbc_tegra *kbc;		/* tegra keyboard controller */
50 	unsigned char inited;		/* 1 if keyboard has been inited */
51 	unsigned char first_scan;	/* 1 if this is our first key scan */
52 
53 	/*
54 	 * After init we must wait a short time before polling the keyboard.
55 	 * This gives the tegra keyboard controller time to react after reset
56 	 * and lets us grab keys pressed during reset.
57 	 */
58 	unsigned int init_dly_ms;	/* Delay before we can read keyboard */
59 	unsigned int start_time_ms;	/* Time that we inited (in ms) */
60 	unsigned int last_poll_ms;	/* Time we should last polled */
61 	unsigned int next_repeat_ms;	/* Next time we repeat a key */
62 };
63 
64 /**
65  * reads the keyboard fifo for current keypresses
66  *
67  * @param priv		Keyboard private data
68  * @param fifo		Place to put fifo results
69  * @param max_keycodes	Maximum number of key codes to put in the fifo
70  * @return number of items put into fifo
71  */
72 static int tegra_kbc_find_keys(struct tegra_kbd_priv *priv, int *fifo,
73 			       int max_keycodes)
74 {
75 	struct key_matrix_key keys[KBC_MAX_KPENT], *key;
76 	u32 kp_ent = 0;
77 	int i;
78 
79 	for (key = keys, i = 0; i < KBC_MAX_KPENT; i++, key++) {
80 		/* Get next word */
81 		if (!(i & 3))
82 			kp_ent = readl(&priv->kbc->kp_ent[i / 4]);
83 
84 		key->valid = (kp_ent & KBC_KPENT_VALID) != 0;
85 		key->row = (kp_ent >> 3) & 0xf;
86 		key->col = kp_ent & 0x7;
87 
88 		/* Shift to get next entry */
89 		kp_ent >>= 8;
90 	}
91 	return key_matrix_decode(&priv->matrix, keys, KBC_MAX_KPENT, fifo,
92 				 max_keycodes);
93 }
94 
95 /**
96  * Process all the keypress sequences in fifo and send key codes
97  *
98  * The fifo contains zero or more keypress sets. Each set
99  * consists of from 1-8 keycodes, representing the keycodes which
100  * were simultaneously pressed during that scan.
101  *
102  * This function works through each set and generates ASCII characters
103  * for each. Not that one set may produce more than one ASCII characters -
104  * for example holding down 'd' and 'f' at the same time will generate
105  * two ASCII characters.
106  *
107  * Note: if fifo_cnt is 0, we will tell the input layer that no keys are
108  * pressed.
109  *
110  * @param priv		Keyboard private data
111  * @param fifo_cnt	Number of entries in the keyboard fifo
112  */
113 static void process_fifo(struct tegra_kbd_priv *priv, int fifo_cnt)
114 {
115 	int fifo[KBC_MAX_KPENT];
116 	int cnt = 0;
117 
118 	/* Always call input_send_keycodes() at least once */
119 	do {
120 		if (fifo_cnt)
121 			cnt = tegra_kbc_find_keys(priv, fifo, KBC_MAX_KPENT);
122 
123 		input_send_keycodes(priv->input, fifo, cnt);
124 	} while (--fifo_cnt > 0);
125 }
126 
127 /**
128  * Check the keyboard controller and emit ASCII characters for any keys that
129  * are pressed.
130  *
131  * @param priv		Keyboard private data
132  */
133 static void check_for_keys(struct tegra_kbd_priv *priv)
134 {
135 	int fifo_cnt;
136 
137 	if (!priv->first_scan &&
138 	    get_timer(priv->last_poll_ms) < KBC_REPEAT_RATE_MS)
139 		return;
140 	priv->last_poll_ms = get_timer(0);
141 	priv->first_scan = 0;
142 
143 	/*
144 	 * Once we get here we know the keyboard has been scanned. So if there
145 	 * scan waiting for us, we know that nothing is held down.
146 	 */
147 	fifo_cnt = (readl(&priv->kbc->interrupt) >> 4) & 0xf;
148 	process_fifo(priv, fifo_cnt);
149 }
150 
151 /**
152  * In order to detect keys pressed on boot, wait for the hardware to
153  * complete scanning the keys. This includes time to transition from
154  * Wkup mode to Continous polling mode and the repoll time. We can
155  * deduct the time that's already elapsed.
156  *
157  * @param priv		Keyboard private data
158  */
159 static void kbd_wait_for_fifo_init(struct tegra_kbd_priv *priv)
160 {
161 	if (!priv->inited) {
162 		unsigned long elapsed_time;
163 		long delay_ms;
164 
165 		elapsed_time = get_timer(priv->start_time_ms);
166 		delay_ms = priv->init_dly_ms - elapsed_time;
167 		if (delay_ms > 0) {
168 			udelay(delay_ms * 1000);
169 			debug("%s: delay %ldms\n", __func__, delay_ms);
170 		}
171 
172 		priv->inited = 1;
173 	}
174 }
175 
176 /**
177  * Check the tegra keyboard, and send any keys that are pressed.
178  *
179  * This is called by input_tstc() and input_getc() when they need more
180  * characters
181  *
182  * @param input		Input configuration
183  * @return 1, to indicate that we have something to look at
184  */
185 static int tegra_kbc_check(struct input_config *input)
186 {
187 	struct tegra_kbd_priv *priv = dev_get_priv(input->dev);
188 
189 	kbd_wait_for_fifo_init(priv);
190 	check_for_keys(priv);
191 
192 	return 1;
193 }
194 
195 /* configures keyboard GPIO registers to use the rows and columns */
196 static void config_kbc_gpio(struct tegra_kbd_priv *priv, struct kbc_tegra *kbc)
197 {
198 	int i;
199 
200 	for (i = 0; i < KBC_MAX_GPIO; i++) {
201 		u32 row_cfg, col_cfg;
202 		u32 r_shift = 5 * (i % 6);
203 		u32 c_shift = 4 * (i % 8);
204 		u32 r_mask = 0x1f << r_shift;
205 		u32 c_mask = 0xf << c_shift;
206 		u32 r_offs = i / 6;
207 		u32 c_offs = i / 8;
208 
209 		row_cfg = readl(&kbc->row_cfg[r_offs]);
210 		col_cfg = readl(&kbc->col_cfg[c_offs]);
211 
212 		row_cfg &= ~r_mask;
213 		col_cfg &= ~c_mask;
214 
215 		if (i < priv->matrix.num_rows) {
216 			row_cfg |= ((i << 1) | 1) << r_shift;
217 		} else {
218 			col_cfg |= (((i - priv->matrix.num_rows) << 1) | 1)
219 					<< c_shift;
220 		}
221 
222 		writel(row_cfg, &kbc->row_cfg[r_offs]);
223 		writel(col_cfg, &kbc->col_cfg[c_offs]);
224 	}
225 }
226 
227 /**
228  * Start up the keyboard device
229  */
230 static void tegra_kbc_open(struct tegra_kbd_priv *priv)
231 {
232 	struct kbc_tegra *kbc = priv->kbc;
233 	unsigned int scan_period;
234 	u32 val;
235 
236 	/*
237 	 * We will scan at twice the keyboard repeat rate, so that there is
238 	 * always a scan ready when we check it in check_for_keys().
239 	 */
240 	scan_period = KBC_REPEAT_RATE_MS / 2;
241 	writel(scan_period * KBC_CLOCK_KHZ, &kbc->rpt_dly);
242 	writel(scan_period * KBC_CLOCK_KHZ, &kbc->init_dly);
243 	/*
244 	 * Before reading from the keyboard we must wait for the init_dly
245 	 * plus the rpt_delay, plus 2ms for the row scan time.
246 	 */
247 	priv->init_dly_ms = scan_period * 2 + 2;
248 
249 	val = KBC_DEBOUNCE_COUNT << KBC_DEBOUNCE_CNT_SHIFT;
250 	val |= 1 << KBC_FIFO_TH_CNT_SHIFT;	/* fifo interrupt threshold */
251 	val |= KBC_CONTROL_KBC_EN;		/* enable */
252 	writel(val, &kbc->control);
253 
254 	priv->start_time_ms = get_timer(0);
255 	priv->last_poll_ms = get_timer(0);
256 	priv->next_repeat_ms = priv->last_poll_ms;
257 	priv->first_scan = 1;
258 }
259 
260 static int tegra_kbd_start(struct udevice *dev)
261 {
262 	struct tegra_kbd_priv *priv = dev_get_priv(dev);
263 
264 	/* Set up pin mux and enable the clock */
265 	funcmux_select(PERIPH_ID_KBC, FUNCMUX_DEFAULT);
266 	clock_enable(PERIPH_ID_KBC);
267 	config_kbc_gpio(priv, priv->kbc);
268 
269 	tegra_kbc_open(priv);
270 	debug("%s: Tegra keyboard ready\n", __func__);
271 
272 	return 0;
273 }
274 
275 /**
276  * Set up the tegra keyboard. This is called by the stdio device handler
277  *
278  * We want to do this init when the keyboard is actually used rather than
279  * at start-up, since keyboard input may not currently be selected.
280  *
281  * Once the keyboard starts there will be a period during which we must
282  * wait for the keyboard to init. We do this only when a key is first
283  * read - see kbd_wait_for_fifo_init().
284  *
285  * @return 0 if ok, -ve on error
286  */
287 static int tegra_kbd_probe(struct udevice *dev)
288 {
289 	struct tegra_kbd_priv *priv = dev_get_priv(dev);
290 	struct keyboard_priv *uc_priv = dev_get_uclass_priv(dev);
291 	struct stdio_dev *sdev = &uc_priv->sdev;
292 	struct input_config *input = &uc_priv->input;
293 	int ret;
294 
295 	priv->kbc = (struct kbc_tegra *)devfdt_get_addr(dev);
296 	if ((fdt_addr_t)priv->kbc == FDT_ADDR_T_NONE) {
297 		debug("%s: No keyboard register found\n", __func__);
298 		return -EINVAL;
299 	}
300 	input_set_delays(input, KBC_REPEAT_DELAY_MS, KBC_REPEAT_RATE_MS);
301 
302 	/* Decode the keyboard matrix information (16 rows, 8 columns) */
303 	ret = key_matrix_init(&priv->matrix, 16, 8, 1);
304 	if (ret) {
305 		debug("%s: Could not init key matrix: %d\n", __func__, ret);
306 		return ret;
307 	}
308 	ret = key_matrix_decode_fdt(dev, &priv->matrix);
309 	if (ret) {
310 		debug("%s: Could not decode key matrix from fdt: %d\n",
311 		      __func__, ret);
312 		return ret;
313 	}
314 	input_add_tables(input, false);
315 	if (priv->matrix.fn_keycode) {
316 		ret = input_add_table(input, KEY_FN, -1,
317 				      priv->matrix.fn_keycode,
318 				      priv->matrix.key_count);
319 		if (ret) {
320 			debug("%s: input_add_table() failed\n", __func__);
321 			return ret;
322 		}
323 	}
324 
325 	/* Register the device. init_tegra_keyboard() will be called soon */
326 	priv->input = input;
327 	input->dev = dev;
328 	input->read_keys = tegra_kbc_check;
329 	strcpy(sdev->name, "tegra-kbc");
330 	ret = input_stdio_register(sdev);
331 	if (ret) {
332 		debug("%s: input_stdio_register() failed\n", __func__);
333 		return ret;
334 	}
335 
336 	return 0;
337 }
338 
339 static const struct keyboard_ops tegra_kbd_ops = {
340 	.start	= tegra_kbd_start,
341 };
342 
343 static const struct udevice_id tegra_kbd_ids[] = {
344 	{ .compatible = "nvidia,tegra20-kbc" },
345 	{ }
346 };
347 
348 U_BOOT_DRIVER(tegra_kbd) = {
349 	.name	= "tegra_kbd",
350 	.id	= UCLASS_KEYBOARD,
351 	.of_match = tegra_kbd_ids,
352 	.probe = tegra_kbd_probe,
353 	.ops	= &tegra_kbd_ops,
354 	.priv_auto_alloc_size = sizeof(struct tegra_kbd_priv),
355 };
356