[PATCH 1/6] clk: bcm2835: pll_off should only set CM_PLL_ANARST

kernel at martin.sperl.org kernel at martin.sperl.org
Mon Feb 29 03:39:17 PST 2016

From: Martin Sperl <kernel at martin.sperl.org>

bcm2835_pll_off is currently assigning CM_PLL_ANARST
to the control register.

This patch only sets the CM_PLL_ANARST bit
not resetting any of the other bits, which allows
restoring the register to its original value
via bcm2834_pll_on.

It also now locks during the read/modify/write cycle of
both registers.

Fixes: 41691b8862e2 ("clk: bcm2835: Add support for programming the
audio domain clocks")

Signed-off-by: Martin Sperl <kernel at martin.sperl.org>
 drivers/clk/bcm/clk-bcm2835.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index 5747a9d..2b7c6af 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -913,8 +913,14 @@ static void bcm2835_pll_off(struct clk_hw *hw)
 	struct bcm2835_cprman *cprman = pll->cprman;
 	const struct bcm2835_pll_data *data = pll->data;

-	cprman_write(cprman, data->cm_ctrl_reg, CM_PLL_ANARST);
-	cprman_write(cprman, data->a2w_ctrl_reg, A2W_PLL_CTRL_PWRDN);
+	spin_lock(&cprman->regs_lock);
+	cprman_write(cprman, data->cm_ctrl_reg,
+		     cprman_read(cprman, data->cm_ctrl_reg) |
+		     CM_PLL_ANARST);
+	cprman_write(cprman, data->a2w_ctrl_reg,
+		     cprman_read(cprman, data->a2w_ctrl_reg) |
+		     A2W_PLL_CTRL_PWRDN);
+	spin_unlock(&cprman->regs_lock);

 static int bcm2835_pll_on(struct clk_hw *hw)

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