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clk: at91: usb: propagate rate modification to the parent clk

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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>
This commit is contained in:
Boris Brezillon 2015-03-29 03:45:33 +02:00 committed by Michael Turquette
parent 3a9e9cb65b
commit 4591243102
1 changed files with 49 additions and 15 deletions
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64
drivers/clk/at91/clk-usb.c
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@ -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;
div = DIV_ROUND_CLOSEST(*parent_rate, rate);
if (div > SAM9X5_USB_MAX_DIV + 1)
div = SAM9X5_USB_MAX_DIV + 1;
for (div = 1; div < SAM9X5_USB_MAX_DIV + 2; div++) {
unsigned long tmp_parent_rate;
return DIV_ROUND_CLOSEST(*parent_rate, div);
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;
}
if (!best_diff)
break;
}
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;