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Subject[PATCH v1 3/5] PM / devfreq: tegra20: Use clk_round_rate_unboundly()
The clk_round_rate() doesn't work for us properly if clock rate is bounded
by a min/max rate that is requested by some other clk-user because we're
building devfreq's OPP table based on the rounding.

In particular this becomes a problem if display driver is probed earlier
than devfreq, and thus, display adds a memory bandwidth request using
interconnect API, which results in a minimum clock-rate being set for
the memory clk. In a result, the lowest devfreq OPP rate is getting
limited to the minimum rate imposed by the display driver.

Let's use new clk_round_rate_unboundly() that resolves the problem by
rounding clock rate without taking into account min/max limits imposed by
active clk users.

Signed-off-by: Dmitry Osipenko <>
drivers/devfreq/tegra20-devfreq.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/devfreq/tegra20-devfreq.c b/drivers/devfreq/tegra20-devfreq.c
index ff82bac9ee4e..1bb10ef11dfe 100644
--- a/drivers/devfreq/tegra20-devfreq.c
+++ b/drivers/devfreq/tegra20-devfreq.c
@@ -149,10 +149,10 @@ static int tegra_devfreq_probe(struct platform_device *pdev)

tegra->regs = mc->regs;

- max_rate = clk_round_rate(tegra->emc_clock, ULONG_MAX);
+ max_rate = clk_round_rate_unboundly(tegra->emc_clock, ULONG_MAX);

for (rate = 0; rate <= max_rate; rate++) {
- rate = clk_round_rate(tegra->emc_clock, rate);
+ rate = clk_round_rate_unboundly(tegra->emc_clock, rate);

err = dev_pm_opp_add(&pdev->dev, rate, 0);
if (err) {
 \ /
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