diff options
| author | Boris BREZILLON <boris.brezillon@free-electrons.com> | 2014-09-02 11:50:17 +0400 |
|---|---|---|
| committer | Mike Turquette <mturquette@linaro.org> | 2014-09-03 02:37:22 +0400 |
| commit | 13a6073d4c5db3103011eebe8c68b049323ced20 (patch) | |
| tree | a9e2dee2d3c352d77e7275b28d853eca06fb13ab /drivers/clk/at91 | |
| parent | 87e2ed338f1b56798807ccf12eb6112d25062202 (diff) | |
| download | linux-13a6073d4c5db3103011eebe8c68b049323ced20.tar.xz | |
clk: at91: rework rm9200 USB clock to propagate set_rate to the parent clk
The RM9200 USB clock is actually connected to a single parent (the PLLB)
on which we can apply a specific divider.
The USB clock divider does not allow for fine grained control on the USB
clock frequency, hence propagating the set_rate request to the parent is
the only choice we have to properly configure the USB clock rate.
Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Reported-by: Gaël PORTAY <gael.portay@gmail.com>
Tested-by: Gaël PORTAY <gael.portay@gmail.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Diffstat (limited to 'drivers/clk/at91')
| -rw-r--r-- | drivers/clk/at91/clk-usb.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/clk/at91/clk-usb.c b/drivers/clk/at91/clk-usb.c index 7d1d26a4bd04..183877712c6c 100644 --- a/drivers/clk/at91/clk-usb.c +++ b/drivers/clk/at91/clk-usb.c @@ -238,16 +238,22 @@ static long at91rm9200_clk_usb_round_rate(struct clk_hw *hw, unsigned long rate, unsigned long *parent_rate) { struct at91rm9200_clk_usb *usb = to_at91rm9200_clk_usb(hw); + struct clk *parent = __clk_get_parent(hw->clk); unsigned long bestrate = 0; int bestdiff = -1; unsigned long tmprate; int tmpdiff; int i = 0; - for (i = 0; i < 4; i++) { + for (i = 0; i < RM9200_USB_DIV_TAB_SIZE; i++) { + unsigned long tmp_parent_rate; + if (!usb->divisors[i]) continue; - tmprate = *parent_rate / usb->divisors[i]; + + tmp_parent_rate = rate * usb->divisors[i]; + tmp_parent_rate = __clk_round_rate(parent, tmp_parent_rate); + tmprate = tmp_parent_rate / usb->divisors[i]; if (tmprate < rate) tmpdiff = rate - tmprate; else @@ -256,6 +262,7 @@ static long at91rm9200_clk_usb_round_rate(struct clk_hw *hw, unsigned long rate, if (bestdiff < 0 || bestdiff > tmpdiff) { bestrate = tmprate; bestdiff = tmpdiff; + *parent_rate = tmp_parent_rate; } if (!bestdiff) @@ -311,7 +318,7 @@ at91rm9200_clk_register_usb(struct at91_pmc *pmc, const char *name, init.ops = &at91rm9200_usb_ops; init.parent_names = &parent_name; init.num_parents = 1; - init.flags = 0; + init.flags = CLK_SET_RATE_PARENT; usb->hw.init = &init; usb->pmc = pmc; |