cros_ec: Support systems with no EC interrupt

[karo-tx-uboot.git] / drivers / input / cros_ec_keyb.c

diff --git a/drivers/input/cros_ec_keyb.c b/drivers/input/cros_ec_keyb.c
index c19730822138b2c1a24feb0e95532bf8e1f5b8ce..a2501e02063e0abb4689c1d1994696751875c4d9 100644 (file)
--- a/drivers/input/cros_ec_keyb.c
+++ b/drivers/input/cros_ec_keyb.c
@@ -2,27 +2,13 @@
  * Chromium OS Matrix Keyboard
  *
  * Copyright (c) 2012 The Chromium OS Authors.
- * See file CREDITS for list of people who contributed to this
- * project.
  *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of
- * the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
- * MA 02111-1307 USA
+ * SPDX-License-Identifier:    GPL-2.0+
  */
 
 #include <common.h>
 #include <cros_ec.h>
+#include <errno.h>
 #include <fdtdec.h>
 #include <input.h>
 #include <key_matrix.h>
@@ -54,20 +40,34 @@ static struct keyb {
  * @param config       Keyboard config
  * @param keys         List of keys that we have detected
  * @param max_count    Maximum number of keys to return
- * @return number of pressed keys, 0 for none
+ * @param samep                Set to true if this scan repeats the last, else false
+ * @return number of pressed keys, 0 for none, -EIO on error
  */
 static int check_for_keys(struct keyb *config,
-                          struct key_matrix_key *keys, int max_count)
+                          struct key_matrix_key *keys, int max_count,
+                          bool *samep)
 {
        struct key_matrix_key *key;
+       static struct mbkp_keyscan last_scan;
+       static bool last_scan_valid;
        struct mbkp_keyscan scan;
        unsigned int row, col, bit, data;
        int num_keys;
 
        if (cros_ec_scan_keyboard(config->dev, &scan)) {
                debug("%s: keyboard scan failed\n", __func__);
-               return -1;
+               return -EIO;
        }
+       *samep = last_scan_valid && !memcmp(&last_scan, &scan, sizeof(scan));
+
+       /*
+        * This is a bit odd. The EC has no way to tell us that it has run
+        * out of key scans. It just returns the same scan over and over
+        * again. So the only way to detect that we have run out is to detect
+        * that this scan is the same as the last.
+        */
+       last_scan_valid = true;
+       memcpy(&last_scan, &scan, sizeof(last_scan));
 
        for (col = num_keys = bit = 0; col < config->matrix.num_cols;
                        col++) {
@@ -127,6 +127,7 @@ int cros_ec_kbc_check(struct input_config *input)
        int keycodes[KBC_MAX_KEYS];
        int num_keys, num_keycodes;
        int irq_pending, sent;
+       bool same = false;
 
        /*
         * Loop until the EC has no more keyscan records, or we have
@@ -140,7 +141,10 @@ int cros_ec_kbc_check(struct input_config *input)
        do {
                irq_pending = cros_ec_interrupt_pending(config.dev);
                if (irq_pending) {
-                       num_keys = check_for_keys(&config, keys, KBC_MAX_KEYS);
+                       num_keys = check_for_keys(&config, keys, KBC_MAX_KEYS,
+                                                 &same);
+                       if (num_keys < 0)
+                               return 0;
                        last_num_keys = num_keys;
                        memcpy(last_keys, keys, sizeof(keys));
                } else {
@@ -157,6 +161,13 @@ int cros_ec_kbc_check(struct input_config *input)
                num_keycodes = key_matrix_decode(&config.matrix, keys,
                                num_keys, keycodes, KBC_MAX_KEYS);
                sent = input_send_keycodes(input, keycodes, num_keycodes);
+
+               /*
+                * For those ECs without an interrupt, stop scanning when we
+                * see that the scan is the same as last time.
+                */
+               if ((irq_pending < 0) && same)
+                       break;
        } while (irq_pending && !sent);
 
        return 1;