linux-kernel - [PATCH v8 06/14] USB: typec: tps6598x: Clear dead battery flag

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Message-Id: <20230929143055.31360-7-alkuor@gmail.com>
Date:   Fri, 29 Sep 2023 10:30:47 -0400
From:   Abdel Alkuor <alkuor@...il.com>
To:     heikki.krogerus@...ux.intel.com, krzysztof.kozlowski+dt@...aro.org,
        bryan.odonoghue@...aro.org
Cc:     gregkh@...uxfoundation.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, ryan.eleceng@...il.com,
        robh+dt@...nel.org, conor+dt@...nel.org,
        devicetree@...r.kernel.org, Abdel Alkuor <abdelalkuor@...tab.com>
Subject: [PATCH v8 06/14] USB: typec: tps6598x: Clear dead battery flag

From: Abdel Alkuor <abdelalkuor@...tab.com>

Dead battery flag must be cleared after switching tps25750 to APP mode
so the PD controller becomes fully functional.

Signed-off-by: Abdel Alkuor <abdelalkuor@...tab.com>
---
Changes in v8:
  - No changes
Changes in v7:
  - Add driver name to commit subject
Changes in v6:
  - No changes
Changes in v5:
  - Incorporating tps25750 into tps6598x driver

 drivers/usb/typec/tipd/core.c     | 16 ++++++++++++++++
 drivers/usb/typec/tipd/tps6598x.h |  1 +
 2 files changed, 17 insertions(+)

diff --git a/drivers/usb/typec/tipd/core.c b/drivers/usb/typec/tipd/core.c
index 21b0ea2c9627..2598433a69cf 100644
--- a/drivers/usb/typec/tipd/core.c
+++ b/drivers/usb/typec/tipd/core.c
@@ -946,6 +946,22 @@ static int tps25750_apply_patch(struct tps6598x *tps)
 
 	} while (ret != TPS_MODE_APP);
 
+	/*
+	 * The dead battery flag may be triggered when the controller
+	 * port is connected to a device that can source power and
+	 * attempts to power up both the controller and the board it is on.
+	 * To restore controller functionality, it is necessary to clear
+	 * this flag
+	 */
+	if (status & TPS_BOOT_STATUS_DEAD_BATTERY_FLAG) {
+		ret = tps6598x_exec_cmd(tps, "DBfg", 0, NULL, 0, NULL);
+		if (ret) {
+			dev_err(tps->dev,
+				"failed to clear dead battery %d\n", ret);
+			return ret;
+		}
+	}
+
 	dev_info(tps->dev, "controller switched to \"APP\" mode\n");
 
 	return 0;
diff --git a/drivers/usb/typec/tipd/tps6598x.h b/drivers/usb/typec/tipd/tps6598x.h
index a80d0929f3ee..c000170f4547 100644
--- a/drivers/usb/typec/tipd/tps6598x.h
+++ b/drivers/usb/typec/tipd/tps6598x.h
@@ -200,6 +200,7 @@
 #define TPS_DATA_STATUS_DP_SPEC_PIN_ASSIGNMENT_B    (BIT(2) | BIT(1))
 
 /* BOOT STATUS REG*/
+#define TPS_BOOT_STATUS_DEAD_BATTERY_FLAG	BIT(2)
 #define TPS_BOOT_STATUS_I2C_EEPROM_PRESENT	BIT(3)
 
 #endif /* __TPS6598X_H__ */
-- 
2.34.1