diff options
| -rw-r--r-- | drivers/clk/qcom/clk-rcg2.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c index 9b3aaa7f20ac..30b19bd39d08 100644 --- a/drivers/clk/qcom/clk-rcg2.c +++ b/drivers/clk/qcom/clk-rcg2.c @@ -1304,7 +1304,39 @@ clk_rcg2_shared_recalc_rate(struct clk_hw *hw, unsigned long parent_rate) return clk_rcg2_recalc_rate(hw, parent_rate); } +static int clk_rcg2_shared_init(struct clk_hw *hw) +{ + /* + * This does a few things: + * + * 1. Sets rcg->parked_cfg to reflect the value at probe so that the + * proper parent is reported from clk_rcg2_shared_get_parent(). + * + * 2. Clears the force enable bit of the RCG because we rely on child + * clks (branches) to turn the RCG on/off with a hardware feedback + * mechanism and only set the force enable bit in the RCG when we + * want to make sure the clk stays on for parent switches or + * parking. + * + * 3. Parks shared RCGs on the safe source at registration because we + * can't be certain that the parent clk will stay on during boot, + * especially if the parent is shared. If this RCG is enabled at + * boot, and the parent is turned off, the RCG will get stuck on. A + * GDSC can wedge if is turned on and the RCG is stuck on because + * the GDSC's controller will hang waiting for the clk status to + * toggle on when it never does. + * + * The safest option here is to "park" the RCG at init so that the clk + * can never get stuck on or off. This ensures the GDSC can't get + * wedged. + */ + clk_rcg2_shared_disable(hw); + + return 0; +} + const struct clk_ops clk_rcg2_shared_ops = { + .init = clk_rcg2_shared_init, .enable = clk_rcg2_shared_enable, .disable = clk_rcg2_shared_disable, .get_parent = clk_rcg2_shared_get_parent, |