drivers/input/tegra-kbc.c

   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 <fdtdec.h>
  10 #include <input.h>
  11 #include <key_matrix.h>
  12 #include <stdio_dev.h>
  13 #include <tegra-kbc.h>
  14 #include <asm/io.h>
  15 #include <asm/arch/clock.h>
  16 #include <asm/arch/funcmux.h>
  17 #include <asm/arch-tegra/timer.h>
  18 #include <linux/input.h>
  19
  20 DECLARE_GLOBAL_DATA_PTR;
  21
  22 enum {
  23         KBC_MAX_GPIO            = 24,
  24         KBC_MAX_KPENT           = 8,    /* size of keypress entry queue */
  25 };
  26
  27 #define KBC_FIFO_TH_CNT_SHIFT           14
  28 #define KBC_DEBOUNCE_CNT_SHIFT          4
  29 #define KBC_CONTROL_FIFO_CNT_INT_EN     (1 << 3)
  30 #define KBC_CONTROL_KBC_EN              (1 << 0)
  31 #define KBC_INT_FIFO_CNT_INT_STATUS     (1 << 2)
  32 #define KBC_KPENT_VALID                 (1 << 7)
  33 #define KBC_ST_STATUS                   (1 << 3)
  34
  35 enum {
  36         KBC_DEBOUNCE_COUNT      = 2,
  37         KBC_REPEAT_RATE_MS      = 30,
  38         KBC_REPEAT_DELAY_MS     = 240,
  39         KBC_CLOCK_KHZ           = 32,   /* Keyboard uses a 32KHz clock */
  40 };
  41
  42 /* keyboard controller config and state */
  43 static struct keyb {
  44         struct input_config input;      /* The input layer */
  45         struct key_matrix matrix;       /* The key matrix layer */
  46
  47         struct kbc_tegra *kbc;          /* tegra keyboard controller */
  48         unsigned char inited;           /* 1 if keyboard has been inited */
  49         unsigned char first_scan;       /* 1 if this is our first key scan */
  50         unsigned char created;          /* 1 if driver has been created */
  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 } config;
  62
  63 /**
  64  * reads the keyboard fifo for current keypresses
  65  *
  66  * @param config        Keyboard config
  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  */
  71 static int tegra_kbc_find_keys(struct keyb *config, 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(&config->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(&config->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 config        Keyboard config
 110  * @param fifo_cnt      Number of entries in the keyboard fifo
 111  */
 112 static void process_fifo(struct keyb *config, 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(config, fifo, KBC_MAX_KPENT);
 121
 122                 input_send_keycodes(&config->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 config        Keyboard config
 131  */
 132 static void check_for_keys(struct keyb *config)
 133 {
 134         int fifo_cnt;
 135
 136         if (!config->first_scan &&
 137                         get_timer(config->last_poll_ms) < KBC_REPEAT_RATE_MS)
 138                 return;
 139         config->last_poll_ms = get_timer(0);
 140         config->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(&config->kbc->interrupt) >> 4) & 0xf;
 147         process_fifo(config, 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 config        Keyboard config
 157  */
 158 static void kbd_wait_for_fifo_init(struct keyb *config)
 159 {
 160         if (!config->inited) {
 161                 unsigned long elapsed_time;
 162                 long delay_ms;
 163
 164                 elapsed_time = get_timer(config->start_time_ms);
 165                 delay_ms = config->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                 config->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  */
 184 int tegra_kbc_check(struct input_config *input)
 185 {
 186         kbd_wait_for_fifo_init(&config);
 187         check_for_keys(&config);
 188
 189         return 1;
 190 }
 191
 192 /**
 193  * Test if keys are available to be read
 194  *
 195  * @return 0 if no keys available, 1 if keys are available
 196  */
 197 static int kbd_tstc(void)
 198 {
 199         /* Just get input to do this for us */
 200         return input_tstc(&config.input);
 201 }
 202
 203 /**
 204  * Read a key
 205  *
 206  * TODO: U-Boot wants 0 for no key, but Ctrl-@ is a valid key...
 207  *
 208  * @return ASCII key code, or 0 if no key, or -1 if error
 209  */
 210 static int kbd_getc(void)
 211 {
 212         /* Just get input to do this for us */
 213         return input_getc(&config.input);
 214 }
 215
 216 /* configures keyboard GPIO registers to use the rows and columns */
 217 static void config_kbc_gpio(struct kbc_tegra *kbc)
 218 {
 219         int i;
 220
 221         for (i = 0; i < KBC_MAX_GPIO; i++) {
 222                 u32 row_cfg, col_cfg;
 223                 u32 r_shift = 5 * (i % 6);
 224                 u32 c_shift = 4 * (i % 8);
 225                 u32 r_mask = 0x1f << r_shift;
 226                 u32 c_mask = 0xf << c_shift;
 227                 u32 r_offs = i / 6;
 228                 u32 c_offs = i / 8;
 229
 230                 row_cfg = readl(&kbc->row_cfg[r_offs]);
 231                 col_cfg = readl(&kbc->col_cfg[c_offs]);
 232
 233                 row_cfg &= ~r_mask;
 234                 col_cfg &= ~c_mask;
 235
 236                 if (i < config.matrix.num_rows) {
 237                         row_cfg |= ((i << 1) | 1) << r_shift;
 238                 } else {
 239                         col_cfg |= (((i - config.matrix.num_rows) << 1) | 1)
 240                                         << c_shift;
 241                 }
 242
 243                 writel(row_cfg, &kbc->row_cfg[r_offs]);
 244                 writel(col_cfg, &kbc->col_cfg[c_offs]);
 245         }
 246 }
 247
 248 /**
 249  * Start up the keyboard device
 250  */
 251 static void tegra_kbc_open(void)
 252 {
 253         struct kbc_tegra *kbc = config.kbc;
 254         unsigned int scan_period;
 255         u32 val;
 256
 257         /*
 258          * We will scan at twice the keyboard repeat rate, so that there is
 259          * always a scan ready when we check it in check_for_keys().
 260          */
 261         scan_period = KBC_REPEAT_RATE_MS / 2;
 262         writel(scan_period * KBC_CLOCK_KHZ, &kbc->rpt_dly);
 263         writel(scan_period * KBC_CLOCK_KHZ, &kbc->init_dly);
 264         /*
 265          * Before reading from the keyboard we must wait for the init_dly
 266          * plus the rpt_delay, plus 2ms for the row scan time.
 267          */
 268         config.init_dly_ms = scan_period * 2 + 2;
 269
 270         val = KBC_DEBOUNCE_COUNT << KBC_DEBOUNCE_CNT_SHIFT;
 271         val |= 1 << KBC_FIFO_TH_CNT_SHIFT;      /* fifo interrupt threshold */
 272         val |= KBC_CONTROL_KBC_EN;              /* enable */
 273         writel(val, &kbc->control);
 274
 275         config.start_time_ms = get_timer(0);
 276         config.last_poll_ms = config.next_repeat_ms = get_timer(0);
 277         config.first_scan = 1;
 278 }
 279
 280 /**
 281  * Set up the tegra keyboard. This is called by the stdio device handler
 282  *
 283  * We want to do this init when the keyboard is actually used rather than
 284  * at start-up, since keyboard input may not currently be selected.
 285  *
 286  * Once the keyboard starts there will be a period during which we must
 287  * wait for the keyboard to init. We do this only when a key is first
 288  * read - see kbd_wait_for_fifo_init().
 289  *
 290  * @return 0 if ok, -ve on error
 291  */
 292 static int init_tegra_keyboard(void)
 293 {
 294         /* check if already created */
 295         if (config.created)
 296                 return 0;
 297
 298 #ifdef CONFIG_OF_CONTROL
 299         int     node;
 300
 301         node = fdtdec_next_compatible(gd->fdt_blob, 0,
 302                                           COMPAT_NVIDIA_TEGRA20_KBC);
 303         if (node < 0) {
 304                 debug("%s: cannot locate keyboard node\n", __func__);
 305                 return node;
 306         }
 307         config.kbc = (struct kbc_tegra *)fdtdec_get_addr(gd->fdt_blob,
 308                        node, "reg");
 309         if ((fdt_addr_t)config.kbc == FDT_ADDR_T_NONE) {
 310                 debug("%s: No keyboard register found\n", __func__);
 311                 return -1;
 312         }
 313         input_set_delays(&config.input, KBC_REPEAT_DELAY_MS,
 314                         KBC_REPEAT_RATE_MS);
 315
 316         /* Decode the keyboard matrix information (16 rows, 8 columns) */
 317         if (key_matrix_init(&config.matrix, 16, 8, 1)) {
 318                 debug("%s: Could not init key matrix\n", __func__);
 319                 return -1;
 320         }
 321         if (key_matrix_decode_fdt(&config.matrix, gd->fdt_blob, node)) {
 322                 debug("%s: Could not decode key matrix from fdt\n", __func__);
 323                 return -1;
 324         }
 325         if (config.matrix.fn_keycode) {
 326                 if (input_add_table(&config.input, KEY_FN, -1,
 327                                     config.matrix.fn_keycode,
 328                                     config.matrix.key_count))
 329                         return -1;
 330         }
 331 #else
 332 #error "Tegra keyboard driver requires FDT definitions"
 333 #endif
 334
 335         /* Set up pin mux and enable the clock */
 336         funcmux_select(PERIPH_ID_KBC, FUNCMUX_DEFAULT);
 337         clock_enable(PERIPH_ID_KBC);
 338         config_kbc_gpio(config.kbc);
 339
 340         tegra_kbc_open();
 341         config.created = 1;
 342         debug("%s: Tegra keyboard ready\n", __func__);
 343
 344         return 0;
 345 }
 346
 347 int drv_keyboard_init(void)
 348 {
 349         struct stdio_dev dev;
 350         char *stdinname = getenv("stdin");
 351         int error;
 352
 353         if (input_init(&config.input, 0)) {
 354                 debug("%s: Cannot set up input\n", __func__);
 355                 return -1;
 356         }
 357         config.input.read_keys = tegra_kbc_check;
 358
 359         memset(&dev, '\0', sizeof(dev));
 360         strcpy(dev.name, "tegra-kbc");
 361         dev.flags = DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
 362         dev.getc = kbd_getc;
 363         dev.tstc = kbd_tstc;
 364         dev.start = init_tegra_keyboard;
 365
 366         /* Register the device. init_tegra_keyboard() will be called soon */
 367         error = input_stdio_register(&dev);
 368         if (error)
 369                 return error;
 370 #ifdef CONFIG_CONSOLE_MUX
 371         error = iomux_doenv(stdin, stdinname);
 372         if (error)
 373                 return error;
 374 #endif
 375         return 0;
 376 }