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Commit 45912431 authored by Boris Brezillon's avatar Boris Brezillon Committed by Michael Turquette
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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: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
Reported-by: default avatarBo Shen <voice.shen@atmel.com>
Tested-by: default avatarBo Shen <voice.shen@atmel.com>
Signed-off-by: default avatarMichael Turquette <mturquette@linaro.org>
parent 3a9e9cb6

drivers/clk/at91/clk-usb.c

+49 −15
Original line number Diff line number Diff line
@@ -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;



	div = DIV_ROUND_CLOSEST(*parent_rate, rate);

	if (div > SAM9X5_USB_MAX_DIV + 1)

		div = SAM9X5_USB_MAX_DIV + 1;

			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 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;