The at91sam9n12 and at91sam9x5 usb clocks do not propagate rate modification requests to their parents. This causes a bug when the PLLB is left uninitialized by the bootloader (PLL multiplier set to 0, or in other words, PLL rate = 0 Hz). Implement the determinate_rate method and propagate the change rate request to the parent clk. Cc: <stable@xxxxxxxxxxxxxxx> # v3.14+ Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx> Reported-by: Bo Shen <voice.shen@xxxxxxxxx> Tested-by: Bo Shen <voice.shen@xxxxxxxxx> --- Hi Mike, I haven't taken Tomeu's rework of the determine_rate prototype [1] into account in this patch, but will do once his patch series is accepted. Best Regards, Boris [1] https://lkml.org/lkml/2015/1/23/222 drivers/clk/at91/clk-usb.c | 62 +++++++++++++++++++++++++++++++++++----------- 1 file changed, 47 insertions(+), 15 deletions(-) diff --git a/drivers/clk/at91/clk-usb.c b/drivers/clk/at91/clk-usb.c index a23ac0c..0283a57 100644 --- a/drivers/clk/at91/clk-usb.c +++ b/drivers/clk/at91/clk-usb.c @@ -56,22 +56,53 @@ static unsigned long at91sam9x5_clk_usb_recalc_rate(struct clk_hw *hw, return DIV_ROUND_CLOSEST(parent_rate, (usbdiv + 1)); } -static long at91sam9x5_clk_usb_round_rate(struct clk_hw *hw, unsigned long rate, - unsigned long *parent_rate) +static long at91sam9x5_clk_usb_determine_rate(struct clk_hw *hw, + unsigned long rate, + unsigned long *best_parent_rate, + struct clk_hw **best_parent_hw) { - unsigned long div; + struct clk *parent = NULL; + long best_rate = -EINVAL; + unsigned long tmp_rate; + int best_diff = -1; + int tmp_diff; + int i; - if (!rate) - return -EINVAL; + for (i = 0; i < __clk_get_num_parents(hw->clk); i++) { + int div; - if (rate >= *parent_rate) - return *parent_rate; + parent = clk_get_parent_by_index(hw->clk, i); + if (!parent) + continue; + + for (div = 1; div < SAM9X5_USB_MAX_DIV + 2; div++) { + unsigned long tmp_parent_rate; + + tmp_parent_rate = rate * div; + tmp_parent_rate = __clk_round_rate(parent, + tmp_parent_rate); + tmp_rate = DIV_ROUND_CLOSEST(tmp_parent_rate, div); + if (tmp_rate < rate) + tmp_diff = rate - tmp_rate; + else + tmp_diff = tmp_rate - rate; + + if (best_diff < 0 || best_diff > tmp_diff) { + best_rate = tmp_rate; + best_diff = tmp_diff; + *best_parent_rate = tmp_parent_rate; + *best_parent_hw = __clk_get_hw(parent); + } + + if (!best_diff || tmp_rate < rate) + break; + } - div = DIV_ROUND_CLOSEST(*parent_rate, rate); - if (div > SAM9X5_USB_MAX_DIV + 1) - div = SAM9X5_USB_MAX_DIV + 1; + if (!best_diff) + break; + } - return DIV_ROUND_CLOSEST(*parent_rate, div); + return best_rate; } static int at91sam9x5_clk_usb_set_parent(struct clk_hw *hw, u8 index) @@ -121,7 +152,7 @@ static int at91sam9x5_clk_usb_set_rate(struct clk_hw *hw, unsigned long rate, static const struct clk_ops at91sam9x5_usb_ops = { .recalc_rate = at91sam9x5_clk_usb_recalc_rate, - .round_rate = at91sam9x5_clk_usb_round_rate, + .determine_rate = at91sam9x5_clk_usb_determine_rate, .get_parent = at91sam9x5_clk_usb_get_parent, .set_parent = at91sam9x5_clk_usb_set_parent, .set_rate = at91sam9x5_clk_usb_set_rate, @@ -159,7 +190,7 @@ static const struct clk_ops at91sam9n12_usb_ops = { .disable = at91sam9n12_clk_usb_disable, .is_enabled = at91sam9n12_clk_usb_is_enabled, .recalc_rate = at91sam9x5_clk_usb_recalc_rate, - .round_rate = at91sam9x5_clk_usb_round_rate, + .determine_rate = at91sam9x5_clk_usb_determine_rate, .set_rate = at91sam9x5_clk_usb_set_rate, }; @@ -179,7 +210,8 @@ at91sam9x5_clk_register_usb(struct at91_pmc *pmc, const char *name, init.ops = &at91sam9x5_usb_ops; init.parent_names = parent_names; init.num_parents = num_parents; - init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE; + init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE | + CLK_SET_RATE_PARENT; usb->hw.init = &init; usb->pmc = pmc; @@ -207,7 +239,7 @@ at91sam9n12_clk_register_usb(struct at91_pmc *pmc, const char *name, init.ops = &at91sam9n12_usb_ops; init.parent_names = &parent_name; init.num_parents = 1; - init.flags = CLK_SET_RATE_GATE; + init.flags = CLK_SET_RATE_GATE | CLK_SET_RATE_PARENT; usb->hw.init = &init; usb->pmc = pmc; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html