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From:   Ping-Ke Shih <pkshih@realtek.com>
To:     <tony0620emma@gmail.com>, <kvalo@codeaurora.org>
CC:     <linux-wireless@vger.kernel.org>, <timlee@realtek.com>
Subject: [PATCH] rtw88: 8822ce: set CLKREQ# signal to low during suspend
Date:   Tue, 27 Jul 2021 18:05:03 +0800
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From: Chin-Yen Lee <timlee@realtek.com>

We find the power sequence of system suspend flow don't meet
the criteria when using 8822CE-VR chip by rfe-type 6, because the
reference clock form host is sometimes late. To avoid the behavoir,
we keep CLKREQ# signal to low during suspend to make sure the reference
clock arrival in time.

Signed-off-by: Chin-Yen Lee <timlee@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
---
 drivers/net/wireless/realtek/rtw88/pci.c | 33 ++++++++++++++++++++++++
 drivers/net/wireless/realtek/rtw88/pci.h |  1 +
 2 files changed, 34 insertions(+)

diff --git a/drivers/net/wireless/realtek/rtw88/pci.c b/drivers/net/wireless/realtek/rtw88/pci.c
index e7d17ab8f113..0f95a9555aea 100644
--- a/drivers/net/wireless/realtek/rtw88/pci.c
+++ b/drivers/net/wireless/realtek/rtw88/pci.c
@@ -1359,6 +1359,25 @@ static void rtw_pci_clkreq_set(struct rtw_dev *rtwdev, bool enable)
 	rtw_dbi_write8(rtwdev, RTK_PCIE_LINK_CFG, value);
 }
 
+static void rtw_pci_clkreq_pad_low(struct rtw_dev *rtwdev, bool enable)
+{
+	u8 value;
+	int ret;
+
+	ret = rtw_dbi_read8(rtwdev, RTK_PCIE_LINK_CFG, &value);
+	if (ret) {
+		rtw_err(rtwdev, "failed to read CLKREQ_L1, ret=%d", ret);
+		return;
+	}
+
+	if (enable)
+		value &= ~BIT_CLKREQ_N_PAD;
+	else
+		value |= BIT_CLKREQ_N_PAD;
+
+	rtw_dbi_write8(rtwdev, RTK_PCIE_LINK_CFG, value);
+}
+
 static void rtw_pci_aspm_set(struct rtw_dev *rtwdev, bool enable)
 {
 	u8 value;
@@ -1500,11 +1519,25 @@ static void rtw_pci_phy_cfg(struct rtw_dev *rtwdev)
 
 static int __maybe_unused rtw_pci_suspend(struct device *dev)
 {
+	struct ieee80211_hw *hw = dev_get_drvdata(dev);
+	struct rtw_dev *rtwdev = hw->priv;
+	struct rtw_chip_info *chip = rtwdev->chip;
+	struct rtw_efuse *efuse = &rtwdev->efuse;
+
+	if (chip->id == RTW_CHIP_TYPE_8822C && efuse->rfe_option == 6)
+		rtw_pci_clkreq_pad_low(rtwdev, true);
 	return 0;
 }
 
 static int __maybe_unused rtw_pci_resume(struct device *dev)
 {
+	struct ieee80211_hw *hw = dev_get_drvdata(dev);
+	struct rtw_dev *rtwdev = hw->priv;
+	struct rtw_chip_info *chip = rtwdev->chip;
+	struct rtw_efuse *efuse = &rtwdev->efuse;
+
+	if (chip->id == RTW_CHIP_TYPE_8822C && efuse->rfe_option == 6)
+		rtw_pci_clkreq_pad_low(rtwdev, false);
 	return 0;
 }
 
diff --git a/drivers/net/wireless/realtek/rtw88/pci.h b/drivers/net/wireless/realtek/rtw88/pci.h
index 0ffae887527a..66f78eb7757c 100644
--- a/drivers/net/wireless/realtek/rtw88/pci.h
+++ b/drivers/net/wireless/realtek/rtw88/pci.h
@@ -37,6 +37,7 @@
 #define RTK_PCIE_LINK_CFG	0x0719
 #define BIT_CLKREQ_SW_EN	BIT(4)
 #define BIT_L1_SW_EN		BIT(3)
+#define BIT_CLKREQ_N_PAD	BIT(0)
 #define RTK_PCIE_CLKDLY_CTRL	0x0725
 
 #define BIT_PCI_BCNQ_FLAG	BIT(4)
-- 
2.25.1