Backport: enable LNA for CPE210

This patch massivly improves the wireless performance of CPE210

Signed-off-by: Tobias Klaus <tk+ff@meskal.net>
Tested-by: Tim Niemeyer <tim@tn-x.org>
Reviewed-by: Jan Kraus <mayosemmel@gmail.com>
Reviewed-by: Tim Niemeyer <tim@tn-x.org>

build_patches/openwrt/0005-ar71xx-cpe510-enable-LNA-for-CPE210-220-510-520.patch

+From 94e23bf7409d6cc4c9efb55ed32aba8e5a497966 Mon Sep 17 00:00:00 2001
+From: Alexander Couzens <lynxis@fe80.eu>
+Date: Fri, 20 May 2016 13:10:36 +0200
+Subject: [PATCH] ar71xx/cpe510: enable LNA for CPE210/220/510/520
+
+The LNA improves the rx path. Within a simple test setup
+it improved the signal from -60dbm to -40dbm.
+
+Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
+---
+ target/linux/ar71xx/files/arch/mips/ath79/mach-cpe510.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git target/linux/ar71xx/files/arch/mips/ath79/mach-cpe510.c target/linux/ar71xx/files/arch/mips/ath79/mach-cpe510.c
+index 8bf5c0f..5cb052a 100644
+--- target/linux/ar71xx/files/arch/mips/ath79/mach-cpe510.c
++++ target/linux/ar71xx/files/arch/mips/ath79/mach-cpe510.c
+@@ -30,6 +30,9 @@
+ #define CPE510_GPIO_LED_L3	15
+ #define CPE510_GPIO_LED_L4	16
+ 
++#define CPE510_GPIO_EXTERNAL_LNA0	18
++#define CPE510_GPIO_EXTERNAL_LNA1	19
++
+ #define CPE510_GPIO_BTN_RESET	4
+ 
+ #define CPE510_KEYS_POLL_INTERVAL	20 /* msecs */
+@@ -93,6 +96,9 @@ static void __init cpe510_setup(void)
+ 					ARRAY_SIZE(cpe510_gpio_keys),
+ 					cpe510_gpio_keys);
+ 
++	ath79_wmac_set_ext_lna_gpio(0, CPE510_GPIO_EXTERNAL_LNA0);
++	ath79_wmac_set_ext_lna_gpio(1, CPE510_GPIO_EXTERNAL_LNA1);
++
+ 	ath79_register_m25p80(NULL);
+ 
+ 	ath79_register_mdio(1, 0);
+-- 
+2.10.1
+