CHROMIUM: input: cyapa - fix power mode switch problems

We have found that some commands may fail if the touchpad is
not running at the full mode. Moreover, setting new power modes
would take the amount of time roughly equal to the old scanrate
to complete. The patch fixes several places where the unsafe
commands might be run before completely returning to the full
mode. Meanwhile, the cyapa_set_power_mode function now returns
early if the mode to set is the same as the current one.

Signed-off-by: Tai-Hsu Lin <sheckylin@chromium.org>
BUG=chromium:196520
TEST=Repeatedly suspend/resume the device with Cypress touchpad for
a few hundred times. One should see errors about reading query data
in the /var/log/messages.

With the fix, one shouldn't see the error.

Change-Id: I95a843a077d5840c57cc24daf85b6549550fa73d
Reviewed-on: https://gerrit.chromium.org/gerrit/46115
Reviewed-by: Benson Leung <bleung@chromium.org>
Commit-Queue: Tai-Hsu Lin <sheckylin@chromium.org>
Tested-by: Tai-Hsu Lin <sheckylin@chromium.org>

diff --git a/drivers/input/mouse/cyapa.c b/drivers/input/mouse/cyapa.c
index eb99956..cd94ced 100644 (file)
--- a/drivers/input/mouse/cyapa.c
+++ b/drivers/input/mouse/cyapa.c
@@ -651,8 +651,11 @@ static int cyapa_poll_state(struct cyapa *cyapa, unsigned int timeout)
        cyapa_dbg(cyapa, "======< cyapa_poll_state >======");
 
        ret = cyapa_get_state(cyapa);
-       if (ret)
+       if (ret) {
+               dev_err(&cyapa->client->dev, "poll state first trial"
+                               " failed\n");
                cyapa->debug = true;
+       }
 
        while ((ret || cyapa->state >= CYAPA_STATE_BL_BUSY) && tries--) {
                msleep(100);
@@ -886,6 +889,25 @@ static u16 cyapa_pwr_cmd_to_sleep_time(u8 pwr_mode)
                                   : (encoded_time - 5) * 20;
 }
 
+/*
+ * cyapa_get_wait_time_for_pwr_cmd
+ *
+ * Compute the amount of time we need to wait after updating the touchpad
+ * power mode. The touchpad needs to consume the incoming power mode set
+ * command at the current clock rate.
+ */
+
+static u16 cyapa_get_wait_time_for_pwr_cmd(u8 pwr_mode)
+{
+       switch (pwr_mode) {
+       case PWR_MODE_FULL_ACTIVE: return 20;
+       case PWR_MODE_BTN_ONLY: return 20;
+       case PWR_MODE_OFF: return 20;
+       default: return cyapa_pwr_cmd_to_sleep_time(pwr_mode) + 50;
+       }
+}
+
+
 /*
  * Set device power mode
  *
@@ -912,6 +934,7 @@ static int cyapa_set_power_mode(struct cyapa *cyapa, u8 power_mode)
        int ret;
        u8 power;
        int tries = SET_POWER_MODE_TRIES;
+       u16 sleep_time;
        cyapa_dbg(cyapa, "======< cyapa_set_power_mode >======");
 
        if (cyapa->state != CYAPA_STATE_OP)
@@ -921,16 +944,26 @@ static int cyapa_set_power_mode(struct cyapa *cyapa, u8 power_mode)
                ret = cyapa_read_byte(cyapa, CYAPA_CMD_POWER_MODE);
                if (ret >= 0 || --tries < 1)
                        break;
-               dev_dbg(dev, "set power mode read retry. tries left = %d\n",
+               dev_dbg(dev, "set_power_mode read retry. tries left = %d\n",
                        tries);
                usleep_range(SET_POWER_MODE_DELAY, 2 * SET_POWER_MODE_DELAY);
        }
        if (ret < 0) {
-               dev_err(dev, "failed to read power mode %d\n", ret);
+               dev_err(dev, "set_power_mode failed to read power mode %d\n",
+                               ret);
                cyapa->debug = true;
                return ret;
        }
+       /*
+        * Return early if the power mode to set is the same as the current
+        * one.
+        */
+       if ((ret & PWR_MODE_MASK) == power_mode) {
+               cyapa_dbg(cyapa, "set_power_mode early return\n");
+               return 0;
+       }
 
+       sleep_time = cyapa_get_wait_time_for_pwr_cmd(ret & PWR_MODE_MASK);
        power = ret;
        power &= ~PWR_MODE_MASK;
        power |= power_mode & PWR_MODE_MASK;
@@ -938,15 +971,22 @@ static int cyapa_set_power_mode(struct cyapa *cyapa, u8 power_mode)
                ret = cyapa_write_byte(cyapa, CYAPA_CMD_POWER_MODE, power);
                if (!ret || --tries < 1)
                        break;
-               dev_dbg(dev, "set power mode write retry. tries left = %d\n",
+               dev_dbg(dev, "set_power_mode write retry. tries left = %d\n",
                        tries);
                usleep_range(SET_POWER_MODE_DELAY, 2 * SET_POWER_MODE_DELAY);
        }
        if (ret < 0) {
-               dev_err(dev, "failed to set power_mode 0x%02x err = %d\n",
-                       power_mode, ret);
+               dev_err(dev, "set_power_mode failed to set power mode"
+                               " 0x%02x err = %d\n", power_mode, ret);
                cyapa->debug = true;
        }
+       /*
+        * Wait for the newly set power command to go in at the previous
+        * clock speed (scanrate) used by the touchpad firmware. Not
+        * doing so before issuing the next command may result in errors
+        * depending on the command's content.
+        */
+       msleep(sleep_time);
        return ret;
 }
 
@@ -1035,6 +1075,16 @@ static int cyapa_check_is_operational(struct cyapa *cyapa)
 
        /* Fallthrough state */
        case CYAPA_STATE_OP:
+               /*
+                * Reading query data before going back to the full mode
+                * may cause problems, so we set the power mode first here.
+                */
+               ret = cyapa_set_power_mode(cyapa, PWR_MODE_FULL_ACTIVE);
+               if (ret) {
+                       dev_err(dev, "check_is_operational active power"
+                                       " failed, %d\n", ret);
+                       cyapa->debug = true;
+               }
                ret = cyapa_get_query_data(cyapa);
                if (ret < 0)
                        return ret;
@@ -1271,8 +1321,6 @@ static int cyapa_firmware(struct cyapa *cyapa, const char *fw_name)
        int ret;
        const struct firmware *fw;
        int i;
-       u8 pwr_cmd = cyapa->runtime_suspend_power_mode;
-       u16 time = cyapa_pwr_cmd_to_sleep_time(pwr_cmd);
        cyapa_dbg(cyapa, "======< cyapa_firmware >======");
 
        ret = request_firmware(&fw, fw_name, dev);
@@ -1294,7 +1342,6 @@ static int cyapa_firmware(struct cyapa *cyapa, const char *fw_name)
         * fail.
         */
        pm_runtime_get_sync(dev);
-       msleep(time + 100);
 
        ret = cyapa_bl_enter(cyapa);
        if (ret) {
@@ -1456,6 +1503,7 @@ static ssize_t cyapa_calibrate_store(struct device *dev,
        struct cyapa *cyapa = dev_get_drvdata(dev);
        int tries = 20;  /* max recalibration timeout 2s. */
        int ret;
+       cyapa_dbg(cyapa, "======< cyapa_calibrate_store >======");
 
        disable_irq(cyapa->irq);
 
@@ -1516,6 +1564,7 @@ static ssize_t cyapa_show_baseline(struct device *dev,
        int max_baseline, min_baseline;
        int tries = 3;
        int ret;
+       cyapa_dbg(cyapa, "======< cyapa_show_baseline >======");
 
        disable_irq(cyapa->irq);
 
@@ -2236,7 +2285,7 @@ static int cyapa_suspend(struct device *dev)
                                            : PWR_MODE_OFF;
        ret = cyapa_set_power_mode(cyapa, power_mode);
        if (ret < 0)
-               dev_err(dev, "set power mode failed, %d\n", ret);
+               dev_err(dev, "suspend set power mode failed, %d\n", ret);
 
        if (device_may_wakeup(dev))
                cyapa->irq_wake = (enable_irq_wake(cyapa->irq) == 0);