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 e8dac237a995c0f492d3299921cc6f4fbbaf0f80..a2501e02063e0abb4689c1d1994696751875c4d9 100644 (file)
--- a/drivers/input/cros_ec_keyb.c
+++ b/drivers/input/cros_ec_keyb.c
@@ -8,6 +8,7 @@
 
 #include <common.h>
 #include <cros_ec.h>
+#include <errno.h>
 #include <fdtdec.h>
 #include <input.h>
 #include <key_matrix.h>
@@ -39,20 +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++) {
@@ -112,6 +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
@@ -125,7 +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 {
@@ -142,6 +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;