drivers/input/cros_ec_keyb.c

   1 /*
   2  * Chromium OS Matrix Keyboard
   3  *
   4  * Copyright (c) 2012 The Chromium OS Authors.
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <cros_ec.h>
  11 #include <errno.h>
  12 #include <fdtdec.h>
  13 #include <input.h>
  14 #include <key_matrix.h>
  15 #include <stdio_dev.h>
  16
  17 DECLARE_GLOBAL_DATA_PTR;
  18
  19 enum {
  20         KBC_MAX_KEYS            = 8,    /* Maximum keys held down at once */
  21 };
  22
  23 static struct keyb {
  24         struct cros_ec_dev *dev;                /* The CROS_EC device */
  25         struct input_config input;      /* The input layer */
  26         struct key_matrix matrix;       /* The key matrix layer */
  27         int key_rows;                   /* Number of keyboard rows */
  28         int key_cols;                   /* Number of keyboard columns */
  29         unsigned int repeat_delay_ms;   /* Time before autorepeat starts */
  30         unsigned int repeat_rate_ms;    /* Autorepeat rate in ms */
  31         int ghost_filter;               /* 1 to enable ghost filter, else 0 */
  32         int inited;                     /* 1 if keyboard is ready */
  33 } config;
  34
  35
  36 /**
  37  * Check the keyboard controller and return a list of key matrix positions
  38  * for which a key is pressed
  39  *
  40  * @param config        Keyboard config
  41  * @param keys          List of keys that we have detected
  42  * @param max_count     Maximum number of keys to return
  43  * @param samep         Set to true if this scan repeats the last, else false
  44  * @return number of pressed keys, 0 for none, -EIO on error
  45  */
  46 static int check_for_keys(struct keyb *config,
  47                            struct key_matrix_key *keys, int max_count,
  48                            bool *samep)
  49 {
  50         struct key_matrix_key *key;
  51         static struct mbkp_keyscan last_scan;
  52         static bool last_scan_valid;
  53         struct mbkp_keyscan scan;
  54         unsigned int row, col, bit, data;
  55         int num_keys;
  56
  57         if (cros_ec_scan_keyboard(config->dev, &scan)) {
  58                 debug("%s: keyboard scan failed\n", __func__);
  59                 return -EIO;
  60         }
  61         *samep = last_scan_valid && !memcmp(&last_scan, &scan, sizeof(scan));
  62
  63         /*
  64          * This is a bit odd. The EC has no way to tell us that it has run
  65          * out of key scans. It just returns the same scan over and over
  66          * again. So the only way to detect that we have run out is to detect
  67          * that this scan is the same as the last.
  68          */
  69         last_scan_valid = true;
  70         memcpy(&last_scan, &scan, sizeof(last_scan));
  71
  72         for (col = num_keys = bit = 0; col < config->matrix.num_cols;
  73                         col++) {
  74                 for (row = 0; row < config->matrix.num_rows; row++) {
  75                         unsigned int mask = 1 << (bit & 7);
  76
  77                         data = scan.data[bit / 8];
  78                         if ((data & mask) && num_keys < max_count) {
  79                                 key = keys + num_keys++;
  80                                 key->row = row;
  81                                 key->col = col;
  82                                 key->valid = 1;
  83                         }
  84                         bit++;
  85                 }
  86         }
  87
  88         return num_keys;
  89 }
  90
  91 /**
  92  * Test if keys are available to be read
  93  *
  94  * @return 0 if no keys available, 1 if keys are available
  95  */
  96 static int kbd_tstc(struct stdio_dev *dev)
  97 {
  98         /* Just get input to do this for us */
  99         return config.inited ? input_tstc(&config.input) : 0;
 100 }
 101
 102 /**
 103  * Read a key
 104  *
 105  * @return ASCII key code, or 0 if no key, or -1 if error
 106  */
 107 static int kbd_getc(struct stdio_dev *dev)
 108 {
 109         /* Just get input to do this for us */
 110         return config.inited ? input_getc(&config.input) : 0;
 111 }
 112
 113 /**
 114  * Check the keyboard, and send any keys that are pressed.
 115  *
 116  * This is called by input_tstc() and input_getc() when they need more
 117  * characters
 118  *
 119  * @param input         Input configuration
 120  * @return 1, to indicate that we have something to look at
 121  */
 122 int cros_ec_kbc_check(struct input_config *input)
 123 {
 124         static struct key_matrix_key last_keys[KBC_MAX_KEYS];
 125         static int last_num_keys;
 126         struct key_matrix_key keys[KBC_MAX_KEYS];
 127         int keycodes[KBC_MAX_KEYS];
 128         int num_keys, num_keycodes;
 129         int irq_pending, sent;
 130         bool same = false;
 131
 132         /*
 133          * Loop until the EC has no more keyscan records, or we have
 134          * received at least one character. This means we know that tstc()
 135          * will always return non-zero if keys have been pressed.
 136          *
 137          * Without this loop, a key release (which generates no new ascii
 138          * characters) will cause us to exit this function, and just tstc()
 139          * may return 0 before all keys have been read from the EC.
 140          */
 141         do {
 142                 irq_pending = cros_ec_interrupt_pending(config.dev);
 143                 if (irq_pending) {
 144                         num_keys = check_for_keys(&config, keys, KBC_MAX_KEYS,
 145                                                   &same);
 146                         if (num_keys < 0)
 147                                 return 0;
 148                         last_num_keys = num_keys;
 149                         memcpy(last_keys, keys, sizeof(keys));
 150                 } else {
 151                         /*
 152                          * EC doesn't want to be asked, so use keys from last
 153                          * time.
 154                          */
 155                         num_keys = last_num_keys;
 156                         memcpy(keys, last_keys, sizeof(keys));
 157                 }
 158
 159                 if (num_keys < 0)
 160                         return -1;
 161                 num_keycodes = key_matrix_decode(&config.matrix, keys,
 162                                 num_keys, keycodes, KBC_MAX_KEYS);
 163                 sent = input_send_keycodes(input, keycodes, num_keycodes);
 164
 165                 /*
 166                  * For those ECs without an interrupt, stop scanning when we
 167                  * see that the scan is the same as last time.
 168                  */
 169                 if ((irq_pending < 0) && same)
 170                         break;
 171         } while (irq_pending && !sent);
 172
 173         return 1;
 174 }
 175
 176 /**
 177  * Decode MBKP keyboard details from the device tree
 178  *
 179  * @param blob          Device tree blob
 180  * @param node          Node to decode from
 181  * @param config        Configuration data read from fdt
 182  * @return 0 if ok, -1 on error
 183  */
 184 static int cros_ec_keyb_decode_fdt(const void *blob, int node,
 185                                 struct keyb *config)
 186 {
 187         /*
 188          * Get keyboard rows and columns - at present we are limited to
 189          * 8 columns by the protocol (one byte per row scan)
 190          */
 191         config->key_rows = fdtdec_get_int(blob, node, "google,key-rows", 0);
 192         config->key_cols = fdtdec_get_int(blob, node, "google,key-columns", 0);
 193         if (!config->key_rows || !config->key_cols ||
 194                         config->key_rows * config->key_cols / 8
 195                                 > CROS_EC_KEYSCAN_COLS) {
 196                 debug("%s: Invalid key matrix size %d x %d\n", __func__,
 197                       config->key_rows, config->key_cols);
 198                 return -1;
 199         }
 200         config->repeat_delay_ms = fdtdec_get_int(blob, node,
 201                                                  "google,repeat-delay-ms", 0);
 202         config->repeat_rate_ms = fdtdec_get_int(blob, node,
 203                                                 "google,repeat-rate-ms", 0);
 204         config->ghost_filter = fdtdec_get_bool(blob, node,
 205                                                "google,ghost-filter");
 206         return 0;
 207 }
 208
 209 /**
 210  * Set up the keyboard. This is called by the stdio device handler.
 211  *
 212  * We want to do this init when the keyboard is actually used rather than
 213  * at start-up, since keyboard input may not currently be selected.
 214  *
 215  * @return 0 if ok, -1 on error
 216  */
 217 static int cros_ec_init_keyboard(struct stdio_dev *dev)
 218 {
 219         const void *blob = gd->fdt_blob;
 220         int node;
 221
 222         config.dev = board_get_cros_ec_dev();
 223         if (!config.dev) {
 224                 debug("%s: no cros_ec device: cannot init keyboard\n",
 225                       __func__);
 226                 return -1;
 227         }
 228         node = fdtdec_next_compatible(blob, 0, COMPAT_GOOGLE_CROS_EC_KEYB);
 229         if (node < 0) {
 230                 debug("%s: Node not found\n", __func__);
 231                 return -1;
 232         }
 233         if (cros_ec_keyb_decode_fdt(blob, node, &config))
 234                 return -1;
 235         input_set_delays(&config.input, config.repeat_delay_ms,
 236                          config.repeat_rate_ms);
 237         if (key_matrix_init(&config.matrix, config.key_rows,
 238                         config.key_cols, config.ghost_filter)) {
 239                 debug("%s: cannot init key matrix\n", __func__);
 240                 return -1;
 241         }
 242         if (key_matrix_decode_fdt(&config.matrix, gd->fdt_blob, node)) {
 243                 debug("%s: Could not decode key matrix from fdt\n", __func__);
 244                 return -1;
 245         }
 246         config.inited = 1;
 247         debug("%s: Matrix keyboard %dx%d ready\n", __func__, config.key_rows,
 248               config.key_cols);
 249
 250         return 0;
 251 }
 252
 253 int drv_keyboard_init(void)
 254 {
 255         struct stdio_dev dev;
 256
 257         if (input_init(&config.input, 0)) {
 258                 debug("%s: Cannot set up input\n", __func__);
 259                 return -1;
 260         }
 261         config.input.read_keys = cros_ec_kbc_check;
 262
 263         memset(&dev, '\0', sizeof(dev));
 264         strcpy(dev.name, "cros-ec-keyb");
 265         dev.flags = DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
 266         dev.getc = kbd_getc;
 267         dev.tstc = kbd_tstc;
 268         dev.start = cros_ec_init_keyboard;
 269
 270         /* Register the device. cros_ec_init_keyboard() will be called soon */
 271         return input_stdio_register(&dev);
 272 }