drivers/input/tegra-kbc.c

   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  */
  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  */
 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  */
 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  */
 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  */
 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 */
 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  */
 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
 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  */
 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 };