linux-kernel - [PATCH v2 2/2] clk: bcm2835: Fix PLL poweron

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Message-Id: <1460577903-32192-2-git-send-email-eric@anholt.net>
Date:	Wed, 13 Apr 2016 13:05:03 -0700
From:	Eric Anholt <eric@...olt.net>
To:	linux-rpi-kernel@...ts.infradead.org
Cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Stephen Warren <swarren@...dotorg.org>,
	Lee Jones <lee@...nel.org>,
	Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...eaurora.org>,
	Eric Anholt <eric@...olt.net>, stable@...r.kernel.org
Subject: [PATCH v2 2/2] clk: bcm2835: Fix PLL poweron

In poweroff, we set the reset bit and the power down bit, but only
managed to unset the reset bit for poweron.  This meant that if HDMI
did -EPROBE_DEFER after it had grabbed its clocks, we'd power down the
PLLH (that had been on at boot time) and never recover.

Signed-off-by: Eric Anholt <eric@...olt.net>
Fixes: 41691b8862e2 ("clk: bcm2835: Add support for programming the audio domain clocks")
Cc: stable@...r.kernel.org
---

v2: add fixes tag

 drivers/clk/bcm/clk-bcm2835.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index 87616ded5bbe..7a7970865c2d 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -554,6 +554,10 @@ static int bcm2835_pll_on(struct clk_hw *hw)
 	const struct bcm2835_pll_data *data = pll->data;
 	ktime_t timeout;
 
+	cprman_write(cprman, data->a2w_ctrl_reg,
+		     cprman_read(cprman, data->a2w_ctrl_reg) &
+		     ~A2W_PLL_CTRL_PWRDN);
+
 	/* Take the PLL out of reset. */
 	cprman_write(cprman, data->cm_ctrl_reg,
 		     cprman_read(cprman, data->cm_ctrl_reg) & ~CM_PLL_ANARST);
-- 
2.8.0.rc3