3.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Boris Brezillon <boris.brezil...@free-electrons.com>
commit 4591243102faa8de92da320edea47219901461e9 upstream.
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.
Signed-off-by: Boris Brezillon <boris.brezil...@free-electrons.com>
Reported-by: Bo Shen <voice.s...@atmel.com>
Tested-by: Bo Shen <voice.s...@atmel.com>
Signed-off-by: Michael Turquette <mturque...@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/clk/at91/clk-usb.c | 72 +++++++++++++++++++++++++++++++++------------
1 file changed, 53 insertions(+), 19 deletions(-)
--- a/drivers/clk/at91/clk-usb.c
+++ b/drivers/clk/at91/clk-usb.c
@@ -56,22 +56,55 @@ static unsigned long at91sam9x5_clk_usb_
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)
-{
- unsigned long div;
-
- if (!rate)
- return -EINVAL;
-
- if (rate >= *parent_rate)
- return *parent_rate;
-
- div = DIV_ROUND_CLOSEST(*parent_rate, rate);
- if (div > SAM9X5_USB_MAX_DIV + 1)
- div = SAM9X5_USB_MAX_DIV + 1;
+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)
+{
+ struct clk *parent = NULL;
+ long best_rate = -EINVAL;
+ unsigned long tmp_rate;
+ int best_diff = -1;
+ int tmp_diff;
+ int i;
+
+ for (i = 0; i < __clk_get_num_parents(hw->clk); i++) {
+ int div;
+
+ 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;
+ }
+
+ 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(s
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_
.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_
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
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;
--
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