linux-kernel - [PATCH v3 2/4] clk: bcm2835: Mark GPIO clocks enabled at boot as critical

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Message-Id: <1464807936-532-3-git-send-email-eric@anholt.net>
Date:	Wed,  1 Jun 2016 12:05:34 -0700
From:	Eric Anholt <eric@...olt.net>
To:	Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...eaurora.org>
Cc:	linux-rpi-kernel@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Stephen Warren <swarren@...dotorg.org>,
	Lee Jones <lee@...nel.org>, Eric Anholt <eric@...olt.net>
Subject: [PATCH v3 2/4] 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.

Signed-off-by: Eric Anholt <eric@...olt.net>
---

v3: Only mark critical if it's on at boot.

 drivers/clk/bcm/clk-bcm2835.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index d9db03cb3fd8..400615baea97 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1239,6 +1239,12 @@ static struct clk *bcm2835_register_clock(struct bcm2835_cprman *cprman,
 	} else {
 		init.ops = &bcm2835_clock_clk_ops;
 		init.flags |= CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
+
+		/* If the clock wasn't actually enabled at boot, it's not
+		 * critical.
+		 */
+		if (!(cprman_read(cprman, data->ctl_reg) & CM_ENABLE))
+			init.flags &= ~CLK_IS_CRITICAL;
 	}
 
 	clock = devm_kzalloc(cprman->dev, sizeof(*clock), GFP_KERNEL);
@@ -1708,13 +1714,15 @@ 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(
-- 
2.8.0.rc3