linux-kernel - [PATCH 4.9 020/116] clk: bcm2835: Avoid overwriting the div info when disabling a pll

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Message-Id: <20170106213909.776396441@linuxfoundation.org>
Date:   Fri,  6 Jan 2017 22:43:02 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Boris Brezillon <boris.brezillon@...e-electrons.com>,
        Eric Anholt <eric@...olt.net>,
        Stephen Boyd <sboyd@...eaurora.org>
Subject: [PATCH 4.9 020/116] clk: bcm2835: Avoid overwriting the div info when disabling a pll_div clk

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Boris Brezillon <boris.brezillon@...e-electrons.com>

commit 68af4fa8f39b542a6cde7ac19518d88e9b3099dc upstream.

bcm2835_pll_divider_off() is resetting the divider field in the A2W reg
to zero when disabling the clock.

Make sure we preserve this value by reading the previous a2w_reg value
first and ORing the result with A2W_PLL_CHANNEL_DISABLE.

Signed-off-by: Boris Brezillon <boris.brezillon@...e-electrons.com>
Fixes: 41691b8862e2 ("clk: bcm2835: Add support for programming the audio domain clocks")
Reviewed-by: Eric Anholt <eric@...olt.net>
Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/clk/bcm/clk-bcm2835.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -751,7 +751,9 @@ static void bcm2835_pll_divider_off(stru
 	cprman_write(cprman, data->cm_reg,
 		     (cprman_read(cprman, data->cm_reg) &
 		      ~data->load_mask) | data->hold_mask);
-	cprman_write(cprman, data->a2w_reg, A2W_PLL_CHANNEL_DISABLE);
+	cprman_write(cprman, data->a2w_reg,
+		     cprman_read(cprman, data->a2w_reg) |
+		     A2W_PLL_CHANNEL_DISABLE);
 	spin_unlock(&cprman->regs_lock);
 }