[PATCH rtw-next v2 3/3] wifi: rtw88: 8723b: Read the chip variant from efuse

[Bitterblue Smith <rtl8821cerfe2@gmail.com>]

The RTL8703AS appears to be a variant of RTL8723BS which doesn't support
40 MHz channel width, so read the chip variant from efuse and disable
support for 40 MHz.

Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
---
v2:
 - Split into a separate patch.
 - Get the byte from the efuse physical map stored in RAM instead of
   reading it again from the chip.
 - Use macros for the address, mask, and chip variants.
---
 drivers/net/wireless/realtek/rtw88/rtw8723b.c | 13 +++++++++++++
 drivers/net/wireless/realtek/rtw88/rtw8723b.h |  3 +++
 2 files changed, 16 insertions(+)

diff --git a/drivers/net/wireless/realtek/rtw88/rtw8723b.c b/drivers/net/wireless/realtek/rtw88/rtw8723b.c
index f550c8708e01..48102baf66fc 100644
--- a/drivers/net/wireless/realtek/rtw88/rtw8723b.c
+++ b/drivers/net/wireless/realtek/rtw88/rtw8723b.c
@@ -2376,6 +2376,18 @@ static void rtw8723b_read_package_type(struct rtw_dev *rtwdev, u8 *phy_map)
 	}
 }
 
+static void rtw8723b_read_chip_variant(struct rtw_dev *rtwdev, u8 *phy_map)
+{
+	u8 val_1fb, variant;
+
+	val_1fb = phy_map[RTW8723B_EFUSE_PACKAGE_TYPE];
+	variant = u8_get_bits(val_1fb, RTW8723B_VARIANT_MASK);
+
+	if (rtw_hci_type(rtwdev) == RTW_HCI_TYPE_SDIO &&
+	    variant == RTW8723B_VARIANT_8703AS)
+		rtwdev->efuse.hw_cap.bw &= ~BIT(RTW_CHANNEL_WIDTH_40);
+}
+
 static int rtw8723b_read_efuse(struct rtw_dev *rtwdev, u8 *log_map, u8 *phy_map)
 {
 	struct rtw_efuse *efuse = &rtwdev->efuse;
@@ -2402,6 +2414,7 @@ static int rtw8723b_read_efuse(struct rtw_dev *rtwdev, u8 *log_map, u8 *phy_map)
 			   BIT(RTW_CHANNEL_WIDTH_40);
 
 	rtw8723b_read_package_type(rtwdev, phy_map);
+	rtw8723b_read_chip_variant(rtwdev, phy_map);
 
 	return 0;
 }
diff --git a/drivers/net/wireless/realtek/rtw88/rtw8723b.h b/drivers/net/wireless/realtek/rtw88/rtw8723b.h
index f1eaf7ab2a81..39b92ec5153b 100644
--- a/drivers/net/wireless/realtek/rtw88/rtw8723b.h
+++ b/drivers/net/wireless/realtek/rtw88/rtw8723b.h
@@ -19,6 +19,9 @@ enum rtw8723b_package_type {
 
 #define RTW8723B_EFUSE_PACKAGE_TYPE	0x1fb
 #define RTW8723B_PACKAGE_TYPE_MASK	GENMASK(2, 0)
+#define RTW8723B_VARIANT_MASK		GENMASK(5, 4)
+#define RTW8723B_VARIANT_8723BS		0x3
+#define RTW8723B_VARIANT_8703AS		0x2
 
 extern const struct rtw_chip_info rtw8723b_hw_spec;
 
-- 
2.55.0