1 files changed, 35 insertions, 2 deletions

diff --git a/drivers/input/keyboard/stmpe-keypad.c b/drivers/input/keyboard/stmpe-keypad.c
index 8d1e7af3c5b1..64514e64d557 100644
--- a/drivers/input/keyboard/stmpe-keypad.c
+++ b/drivers/input/keyboard/stmpe-keypad.c
@@ -52,6 +52,7 @@
  * struct stmpe_keypad_variant - model-specific attributes
  * @auto_increment: whether the KPC_DATA_BYTE register address
  *                  auto-increments on multiple read
+ * @set_pullup: whether the pins need to have their pull-ups set
  * @num_data: number of data bytes
  * @num_normal_data: number of normal keys' data bytes
  * @max_cols: maximum number of columns supported
@@ -61,6 +62,7 @@
  */
 struct stmpe_keypad_variant {
         bool            auto_increment;
+        bool            set_pullup;
         int             num_data;
         int             num_normal_data;
         int             max_cols;
@@ -81,6 +83,7 @@ static const struct stmpe_keypad_variant stmpe_keypad_variants[] = {
         },
         [STMPE2401] = {
                 .auto_increment         = false,
+                .set_pullup             = true,
                 .num_data               = 3,
                 .num_normal_data        = 2,
                 .max_cols               = 8,
@@ -90,6 +93,7 @@ static const struct stmpe_keypad_variant stmpe_keypad_variants[] = {
         },
         [STMPE2403] = {
                 .auto_increment         = true,
+                .set_pullup             = true,
                 .num_data               = 5,
                 .num_normal_data        = 3,
                 .max_cols               = 8,
@@ -185,7 +189,10 @@ static int stmpe_keypad_altfunc_init(struct stmpe_keypad *keypad)
         unsigned int col_gpios = variant->col_gpios;
         unsigned int row_gpios = variant->row_gpios;
         struct stmpe *stmpe = keypad->stmpe;
+        u8 pureg = stmpe->regs[STMPE_IDX_GPPUR_LSB];
         unsigned int pins = 0;
+        unsigned int pu_pins = 0;
+        int ret;
         int i;
 
         /*
@@ -202,8 +209,10 @@ static int stmpe_keypad_altfunc_init(struct stmpe_keypad *keypad)
         for (i = 0; i < variant->max_cols; i++) {
                 int num = __ffs(col_gpios);
 
-                if (keypad->cols & (1 << i))
+                if (keypad->cols & (1 << i)) {
                         pins |= 1 << num;
+                        pu_pins |= 1 << num;
+                }
 
                 col_gpios &= ~(1 << num);
         }
@@ -217,7 +226,31 @@ static int stmpe_keypad_altfunc_init(struct stmpe_keypad *keypad)
                 row_gpios &= ~(1 << num);
         }
 
-        return stmpe_set_altfunc(stmpe, pins, STMPE_BLOCK_KEYPAD);
+        ret = stmpe_set_altfunc(stmpe, pins, STMPE_BLOCK_KEYPAD);
+        if (ret)
+                return ret;
+
+        /*
+         * On STMPE24xx, set pin bias to pull-up on all keypad input
+         * pins (columns), this incidentally happen to be maximum 8 pins
+         * and placed at GPIO0-7 so only the LSB of the pull up register
+         * ever needs to be written.
+         */
+        if (variant->set_pullup) {
+                u8 val;
+
+                ret = stmpe_reg_read(stmpe, pureg);
+                if (ret)
+                        return ret;
+
+                /* Do not touch unused pins, may be used for GPIO */
+                val = ret & ~pu_pins;
+                val |= pu_pins;
+
+                ret = stmpe_reg_write(stmpe, pureg, val);
+        }
+
+        return 0;
 }
 
 static int stmpe_keypad_chip_init(struct stmpe_keypad *keypad)