openwrt/target/linux/mediatek/patches-4.4/0027-soc-mediatek-PMIC-wrap-Clear-the-vldclr-if-state-mac.patch

From 55231d8299d3dccde8588ed2e86c2bc0ef2e12ce Mon Sep 17 00:00:00 2001
From: Henry Chen <henryc.chen@mediatek.com>
Date: Mon, 4 Jan 2016 20:02:52 +0800
Subject: [PATCH 027/102] soc: mediatek: PMIC wrap: Clear the vldclr if state
 machine stay on FSM_VLDCLR state.

Sometimes PMIC is too busy to send data in time to cause pmic wrap timeout,
because pmic wrap is waiting for FSM_VLDCLR after finishing WACS2_CMD. It
just return error when issue happened, so the state machine will stay on
FSM_VLDCLR state when data send back later by PMIC and timeout again in next
time because pmic wrap waiting for FSM_IDLE state at the beginning of the
read/write function.

Clear the vldclr when timeout if state machine stay on FSM_VLDCLR.

Signed-off-by: Henry Chen <henryc.chen@mediatek.com>
Tested-by: Ricky Liang <jcliang@chromium.org>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
---
 drivers/soc/mediatek/mtk-pmic-wrap.c |   22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

--- a/drivers/soc/mediatek/mtk-pmic-wrap.c
+++ b/drivers/soc/mediatek/mtk-pmic-wrap.c
@@ -412,6 +412,20 @@ static bool pwrap_is_fsm_vldclr(struct p
 	return PWRAP_GET_WACS_FSM(val) == PWRAP_WACS_FSM_WFVLDCLR;
 }
 
+/*
+ * Timeout issue sometimes caused by the last read command
+ * failed because pmic wrap could not got the FSM_VLDCLR
+ * in time after finishing WACS2_CMD. It made state machine
+ * still on FSM_VLDCLR and timeout next time.
+ * Check the status of FSM and clear the vldclr to recovery the
+ * error.
+ */
+static inline void pwrap_leave_fsm_vldclr(struct pmic_wrapper *wrp)
+{
+	if (pwrap_is_fsm_vldclr(wrp))
+		pwrap_writel(wrp, 1, PWRAP_WACS2_VLDCLR);
+}
+
 static bool pwrap_is_sync_idle(struct pmic_wrapper *wrp)
 {
 	return pwrap_readl(wrp, PWRAP_WACS2_RDATA) & PWRAP_STATE_SYNC_IDLE0;
@@ -445,8 +459,10 @@ static int pwrap_write(struct pmic_wrapp
 	int ret;
 
 	ret = pwrap_wait_for_state(wrp, pwrap_is_fsm_idle);
-	if (ret)
+	if (ret) {
+		pwrap_leave_fsm_vldclr(wrp);
 		return ret;
+	}
 
 	pwrap_writel(wrp, (1 << 31) | ((adr >> 1) << 16) | wdata,
 			PWRAP_WACS2_CMD);
@@ -459,8 +475,10 @@ static int pwrap_read(struct pmic_wrappe
 	int ret;
 
 	ret = pwrap_wait_for_state(wrp, pwrap_is_fsm_idle);
-	if (ret)
+	if (ret) {
+		pwrap_leave_fsm_vldclr(wrp);
 		return ret;
+	}
 
 	pwrap_writel(wrp, (adr >> 1) << 16, PWRAP_WACS2_CMD);