zed: update touchpad parameter

Update touchpad parameter for zed.

There's no integer solution for CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_Y
(calculation appended below), this CL also modified the runtime check in
elan tp driver to allow rounding errors.

Math details:
  Given dpi_y = 800, LOGICAL_MAX_Y = 1811, we want to find an integer
  PHYSICAL_MAX_Y such that

    dpi == 254 * LOGICAL_MAX_Y / PHYSICAL_MAX_Y.

  The closest solution is
  1)
    PHYSICAL_MAX_Y = 574,
    254 * LOGICAL_MAX_Y / PHYSICAL_MAX_Y = 801.3832 != dpi_y, or
  2)
    PHYSICAL_MAX_Y = 575,
    254 * LOGICAL_MAX_Y / PHYSICAL_MAX_Y = 799.9895 != dpi_y

  Both cannot pass our runtime verification.

BUG=None
TEST=No "TP mismatch" in ec console
BRANCH=trogdor

Signed-off-by: Ting Shen <phoenixshen@google.com>
Change-Id: I9d0c54d029bb2f9e78114341a6246857b41937b4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2825473
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
Commit-Queue: Ting Shen <phoenixshen@chromium.org>
Tested-by: Ting Shen <phoenixshen@chromium.org>

3 files changed, 26 insertions, 19 deletions

diff --git a/board/hammer/board.h b/board/hammer/board.h
index d9e4236481..642fe908d4 100644
--- a/board/hammer/board.h
+++ b/board/hammer/board.h
@@ -83,6 +83,7 @@
 #endif
 #define CONFIG_LTO
 #define CONFIG_FORCE_CONSOLE_RESUME
+#define CONFIG_MATH_UTIL
 #define CONFIG_STM_HWTIMER32
 
 /* USB Configuration */
diff --git a/board/hammer/variants.h b/board/hammer/variants.h
index e9ebadd0c6..d3ac1f7086 100644
--- a/board/hammer/variants.h
+++ b/board/hammer/variants.h
@@ -53,7 +53,7 @@
 #define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_X 2925
 #define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_Y 1440
 #define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_PRESSURE 511
-#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_X 928 /* tenth of mm */
+#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_X 929 /* tenth of mm */
 #define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_Y 457 /* tenth of mm */
 #define CONFIG_TOUCHPAD_VIRTUAL_SIZE (56*1024)
 #elif defined(BOARD_MAGNEMITE)
@@ -71,7 +71,7 @@
 #define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_X 2925
 #define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_Y 1440
 #define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_PRESSURE 511
-#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_X 928 /* tenth of mm */
+#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_X 929 /* tenth of mm */
 #define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_Y 457 /* tenth of mm */
 #define CONFIG_TOUCHPAD_VIRTUAL_SIZE (56*1024)
 #elif defined(BOARD_STAFF)
@@ -79,8 +79,8 @@
 #define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_X 3206
 #define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_Y 1832
 #define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_PRESSURE 511
-#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_X 1017 /* tenth of mm */
-#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_Y 581 /* tenth of mm */
+#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_X 1018 /* tenth of mm */
+#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_Y 582 /* tenth of mm */
 #define CONFIG_TOUCHPAD_VIRTUAL_SIZE (56*1024)
 #elif defined(BOARD_STAR)
 /* TODO: update correct parameters */
@@ -97,8 +97,8 @@
 #define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_X 2160
 #define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_Y 1573
 #define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_PRESSURE 255
-#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_X 1030 /* tenth of mm */
-#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_Y 750 /* tenth of mm */
+#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_X 1031 /* tenth of mm */
+#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_Y 751 /* tenth of mm */
 #define CONFIG_TOUCHPAD_VIRTUAL_SIZE (CONFIG_UPDATE_PDU_SIZE + 128*1024)
 /* Enable to send heatmap to AP */
 #define CONFIG_USB_ISOCHRONOUS
@@ -108,11 +108,11 @@
 
 /* TODO: update correct parameters */
 #define HAS_I2C_TOUCHPAD
-#define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_X 3207
-#define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_Y 1783
+#define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_X 3340
+#define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_Y 1811
 #define CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_PRESSURE 511
-#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_X 1018 /* tenth of mm */
-#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_Y 566 /* tenth of mm */
+#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_X 1060 /* tenth of mm */
+#define CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_Y 575 /* tenth of mm */
 #define CONFIG_TOUCHPAD_VIRTUAL_SIZE (64*1024)
 #else
 #error "No touchpad information for board."
diff --git a/driver/touchpad_elan.c b/driver/touchpad_elan.c
index d2e28d53a6..6cd07dd2c2 100644
--- a/driver/touchpad_elan.c
+++ b/driver/touchpad_elan.c
@@ -10,6 +10,7 @@
 #include "hwtimer.h"
 #include "hooks.h"
 #include "i2c.h"
+#include "math_util.h"
 #include "sha256.h"
 #include "shared_mem.h"
 #include "task.h"
@@ -311,6 +312,15 @@ static int elan_get_fwinfo(void)
 	return EC_SUCCESS;
 }
 
+/*
+ * - dpi == logical dimension / physical dimension (inches)
+ *   (254 tenths of mm per inch)
+ */
+__maybe_unused static int calc_physical_dimension(int dpi, int logical_dim)
+{
+	return round_divide(254 * logical_dim, dpi);
+}
+
 /* Initialize the controller ICs after reset */
 static void elan_tp_init(void)
 {
@@ -391,17 +401,13 @@ static void elan_tp_init(void)
 		elan_tp_params.pressure_adj, dpi_x, dpi_y);
 
 #ifdef CONFIG_USB_HID_TOUCHPAD
-	/*
-	 * Validity check dimensions provided at build time.
-	 * - dpi == logical dimension / physical dimension (inches)
-	 *   (254 tenths of mm per inch)
-	 */
+	/* Validity check dimensions provided at build time. */
 	if (elan_tp_params.max_x != CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_X ||
 	    elan_tp_params.max_y != CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_Y ||
-	    dpi_x != 254*CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_X /
-				CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_X ||
-	    dpi_y != 254*CONFIG_USB_HID_TOUCHPAD_LOGICAL_MAX_Y /
-				CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_Y) {
+	    calc_physical_dimension(dpi_x, elan_tp_params.max_x) !=
+			CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_X ||
+	    calc_physical_dimension(dpi_y, elan_tp_params.max_y) !=
+			CONFIG_USB_HID_TOUCHPAD_PHYSICAL_MAX_Y) {
 		CPRINTS("*** TP mismatch!");
 	}
 #endif