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