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author | Boris Brezillon <boris.brezillon@free-electrons.com> | 2015-03-29 03:45:33 +0200 |
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committer | Michael Turquette <mturquette@linaro.org> | 2015-04-12 21:08:51 -0700 |
commit | 4591243102faa8de92da320edea47219901461e9 (patch) | |
tree | 896a83de022e746750b31953b2fef4b78fffa537 /drivers/clk/at91 | |
parent | 3a9e9cb65be84d6c64fbe9c69a73c15d59f29454 (diff) | |
download | linux-4591243102faa8de92da320edea47219901461e9.tar.gz linux-4591243102faa8de92da320edea47219901461e9.tar.bz2 linux-4591243102faa8de92da320edea47219901461e9.zip |
clk: at91: usb: propagate rate modification to the parent clk
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@vger.kernel.org> # v3.14+
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reported-by: Bo Shen <voice.shen@atmel.com>
Tested-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Michael Turquette <mturquette@linaro.org>
Diffstat (limited to 'drivers/clk/at91')
-rw-r--r-- | drivers/clk/at91/clk-usb.c | 64 |
1 files changed, 49 insertions, 15 deletions
diff --git a/drivers/clk/at91/clk-usb.c b/drivers/clk/at91/clk-usb.c index a23ac0c724f0..0b7c3e8840ba 100644 --- a/drivers/clk/at91/clk-usb.c +++ b/drivers/clk/at91/clk-usb.c @@ -56,22 +56,55 @@ 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 min_rate, + unsigned long max_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 +154,7 @@ 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 +192,7 @@ 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 +212,8 @@ 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 +241,7 @@ 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; |