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

@@ -1234,6 +1234,15 @@ static struct clk *bcm2835_register_clock(struct bcm2835_cprman *cprman,
 	init.name = data->name;
 	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;
+
 	if (data->is_vpu_clock) {
 		init.ops = &bcm2835_vpu_clock_clk_ops;
 	} else {
@@ -1708,13 +1717,15 @@ static const struct bcm2835_clk_desc clk_desc_array[] = {
 		.div_reg = CM_GP1DIV,
 		.int_bits = 12,
 		.frac_bits = 12,
+		.flags = CLK_IS_CRITICAL,
 		.is_mash_clock = true),
 	[BCM2835_CLOCK_GP2]	= REGISTER_PER_CLK(
 		.name = "gp2",
 		.ctl_reg = CM_GP2CTL,
 		.div_reg = CM_GP2DIV,
 		.int_bits = 12,
-		.frac_bits = 12),
+		.frac_bits = 12,
+		.flags = CLK_IS_CRITICAL),
 
 	/* HDMI state machine */
 	[BCM2835_CLOCK_HSM]	= REGISTER_PER_CLK(