openwrt/target/linux/bcm27xx/patches-5.4/950-0023-clk-bcm2835-Mark-GPIO-clocks-enabled-at-boot-as-crit.patch

From 9eeebf9e7bb7a25a81f72c0e21793614fab49ec4 Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Mon, 9 May 2016 17:28:18 -0700
Subject: [PATCH] clk: bcm2835: Mark GPIO clocks enabled at boot as
 critical.

These divide off of PLLD_PER and are used for the ethernet and wifi
PHYs source PLLs.  Neither of them is currently represented by a phy
device that would grab the clock for us.

This keeps other drivers from killing the networking PHYs when they
disable their own clocks and trigger PLLD_PER's refcount going to 0.

v2: Skip marking as critical if they aren't on at boot.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
 drivers/clk/bcm/clk-bcm2835.c | 9 +++++++++
 1 file changed, 9 insertions(+)

--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1473,6 +1473,15 @@ static struct clk_hw *bcm2835_register_c
 	init.flags = data->flags | CLK_IGNORE_UNUSED;
 
 	/*
+	 * Some GPIO clocks for ethernet/wifi PLLs are marked as
+	 * critical (since some platforms use them), but if the
+	 * firmware didn't have them turned on then they clearly
+	 * aren't actually critical.
+	 */
+	if ((cprman_read(cprman, data->ctl_reg) & CM_ENABLE) == 0)
+		init.flags &= ~CLK_IS_CRITICAL;
+
+	/*
 	 * Pass the CLK_SET_RATE_PARENT flag if we are allowed to propagate
 	 * rate changes on at least of the parents.
 	 */