Fractional clock dividers generate accurate average frequencies but
with jitter, particularly when the integer divisor is small.
Introduce a new metric of clock accuracy to penalise clocks with a good
average but worse jitter compared to clocks with an average which is no
better but with lower jitter. The metric is the ideal rate minus the
worse deviation from that ideal using the nearest integer divisors.
Use this metric for parent selection for clocks requiring low jitter
(currently just PCM).
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Restrict clock sources for the PCM peripheral to the oscillator and
PLLD_PER because other source may have varying rates or be switched off.
Prevent other sources from being selected by replacing their names in
the list of potential parents with dummy entries (entry index is
significant).
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
If a clock has the prediv flag set, both the integer and fractional
parts must be scaled when calculating the resulting frequency.
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
This proved incredibly useful during debugging of the DSI driver, to
see if our clocks were running at rate we requested. Let's leave it
here for the next person interacting with clocks on the platform (and
so that hopefully we can just hook it up to debugfs some day).
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
The DSI pixel clocks are muxed from clocks generated in the analog phy
by the DSI driver. In order to set them as parents, we need to do the
same name lookup dance on them as we do for our root oscillator.
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Our core PLLs are intended to be configured once and left alone. With
the SET_RATE_PARENT, asking to set the PLLD_DSI1 clock rate would
change PLLD just to get closer to the requested DSI clock, thus
changing PLLD_PER, the UART and ethernet PHY clock rates downstream of
it, and breaking ethernet.
We *do* want PLLH to change so that PLLH_AUX can be exactly the value
we want, though. Thus, we need to have a per-divider policy of
whether to pass rate changes up.
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
best_rate is reported as potentially uninitialized by gcc.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Fixes: 155e8b3b0e ("clk: bcm: Support rate change propagation on bcm2835 clocks")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
The VEC clock requires needs to be set at exactly 108MHz. Allow rate
change propagation on PLLH_AUX to match this requirement wihtout
impacting other IPs (PLLH is currently only used by the HDMI encoder,
which cannot be enabled when the VEC encoder is enabled).
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Some peripheral clocks, like the VEC (Video EnCoder) clock need to be set
to a precise rate (in our case 108MHz). With the current implementation,
where peripheral clocks are not allowed to forward rate change requests
to their parents, it is impossible to match this requirement unless the
bootloader has configured things correctly, or a specific rate has been
assigned through the DT (with the assigned-clk-rates property).
Add a new field to struct bcm2835_clock_data to specify which parent
clocks accept rate change propagation, and support set rate propagation
in bcm2835_clock_determine_rate().
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
bcm2835_pll_divider_off() is resetting the divider field in the A2W reg
to zero when disabling the clock.
Make sure we preserve this value by reading the previous a2w_reg value
first and ORing the result with A2W_PLL_CHANNEL_DISABLE.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Fixes: 41691b8862 ("clk: bcm2835: Add support for programming the audio domain clocks")
Cc: <stable@vger.kernel.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
There is no fixed divider on pllh_aux.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Fixes setting low-resolution video modes on HDMI. Now the PLLH_PIX
divider adjusts itself until the PLLH is within bounds.
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Now that we have clk_hw based provider APIs to register clks, we
can get rid of struct clk pointers while registering clks in
these drivers, allowing us to move closer to a clear split of
consumer and provider clk APIs.
Cc: Eric Anholt <eric@anholt.net>
Cc: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
If the firmware had set up a clock to source from PLLC, go along with
it. But if we're looking for a new parent, we don't want to switch it
to PLLC because the firmware will force PLLC (and thus the AXI bus
clock) to different frequencies during over-temp/under-voltage,
without notification to Linux.
On my system, this moves the Linux-enabled HDMI state machine and DSI1
escape clock over to plld_per from pllc_per. EMMC still ends up on
pllc_per, because the firmware had set it up to use that.
Signed-off-by: Eric Anholt <eric@anholt.net>
Fixes: 41691b8862 ("clk: bcm2835: Add support for programming the audio domain clocks")
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
While the SDRAM is being driven by its dedicated PLL most of the time,
there is a little loop running in the firmware that periodically turns
on the CM SDRAM clock (using its pre-initialized parent) and switches
SDRAM to using the CM clock to do PVT recalibration.
This avoids system hangs if we choose SDRAM's parent for some other
clock, then disable that clock.
Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
These divide off of PLLD_PER and are used for the ethernet and wifi
PHYs source PLLs. Neither of them is currently represented by a phy
device that would grab the clock for us.
This keeps other drivers from killing the networking PHYs when they
disable their own clocks and trigger PLLD_PER's refcount going to 0.
Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
The VPU clock is also the clock for our AXI bus, so we really can't
disable it. This might have happened during boot if, for example,
uart1 (aux_uart clock) probed and was then disabled before the other
consumers of the VPU clock had probed.
Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
In poweroff, we set the reset bit and the power down bit, but only
managed to unset the reset bit for poweron. This meant that if HDMI
did -EPROBE_DEFER after it had grabbed its clocks, we'd power down the
PLLH (that had been on at boot time) and never recover.
Signed-off-by: Eric Anholt <eric@anholt.net>
Fixes: 41691b8862 ("clk: bcm2835: Add support for programming the audio domain clocks")
Cc: stable@vger.kernel.org
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Add AVE0, DFT, GP0, GP1, GP2, SLIM, SMI, TEC, DPI, CAM0, CAM1, DSI0E,
and DSI1E. PULSE is not added because it has an extra divider.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Enable the PCM clock in the SOC, which is used by the
bcm2835-i2s driver.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reorganize bcm2835_clock_array so that there is no more
need for separate bcm2835_*_data structures to be defined.
Instead the required structures are generated inline via
helper macros.
To allow this to also work for pll alone it was required that
the parent_pll was changed from a pointer to bcm2835_pll_data
to the name of the pll instead.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
As the use of BCM2835_CLOCK_COUNT in
include/dt-bindings/clock/bcm2835.h is frowned upon as
it needs to get modified every time a new clock gets introduced
this patch changes the clk-bcm2835 driver to use a different
scheme for registration of clocks and pll, so that there
is no more need for BCM2835_CLOCK_COUNT to be defined.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
For debugging purposes under some circumstance
it helps to be able to see the actual clock registers.
E.g: when looking at the clock divider it is helpful to
see what the actual clock divider is.
This patch exposes all the clock registers specific to each
clock/pll/pll-divider via debugfs.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Eric Anholt <eric@anholt.net>
The current driver calculates the clock divider with
fractional support enabled.
But it does not enable fractional support in the
control register itself resulting in an integer only divider,
but in clk_set_rate responds back the fractionally divided
clock frequency.
This patch enables fractional support in the control register
whenever there is a fractional bit set in the requested clock divider.
Mash clock limits are are also handled for the PWM clock
applying the correct divider limits (2 and max_int) applicable to
basic fractional divider support (mash order of 1).
It also adds locking to protect the read/modify/write cycle of
the register modification.
Fixes: 41691b8862 ("clk: bcm2835: Add support for programming the
audio domain clocks")
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Current clamping of a normal divider allows a value < 1 to be valid.
A divider of < 1 would actually only be possible if we had a PLL...
So this patch clamps the divider to 1.
Fixes: 41691b8862 ("clk: bcm2835: Add support for programming the
audio domain clocks")
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Add missing locking to:
* bcm2835_pll_divider_on
* bcm2835_pll_divider_off
to protect the read modify write cycle for the
register access protecting both cm_reg and a2w_reg
registers.
Fixes: 41691b8862 ("clk: bcm2835: Add support for programming the
audio domain clocks")
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
bcm2835_pll_off is currently assigning CM_PLL_ANARST to the control
register, which may lose the other bits that are currently set by the
clock dividers.
It also now locks during the read/modify/write cycle of both
registers.
Fixes: 41691b8862 ("clk: bcm2835: Add support for programming the
audio domain clocks")
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
This flag is a no-op now. Remove usage of the flag.
Cc: Lee Jones <lee@kernel.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
We were rolling this ourselves, but clk-divider can do it now.
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Our dividers weren't being set successfully because CM_PASSWORD wasn't
included in the register write. It looks easier to just compute the
divider to write ourselves than to update clk-divider for the ability
to OR in some arbitrary bits on write.
Fixes about half of the video modes on my HDMI monitor (everything
except 720x400).
Cc: stable@vger.kernel.org
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Register the pwm clock for bcm2835.
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Some bcm2835 clocks used by hardware (like "PWM" or "H264") can have multiple
parent clocks. These clocks divide the rate of a parent which can be selected by
setting the proper bits in the clock control register.
Previously all these parents where handled by a mux clock. But a mux clock
cannot be used because updating clock control register to select parent needs a
password to be xor'd with the parent index.
This patch get rid of mux clock and make these clocks handle their own parent,
allowing them to select the one to use.
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Make bcm2835_clock_choose_div to optionally round up the chosen MASH divisor
so that the resulting average rate will not be higher than the requested one.
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
This adds support for enabling, disabling, and setting the rate of the
audio domain clocks. It will be necessary for setting the pixel clock
for HDMI in the VC4 driver and let us write a cpufreq driver. It will
also improve compatibility with user changes to the firmware's
config.txt, since our previous fixed clocks are unaware of it.
The firmware also has support for configuring the clocks through the
mailbox channel, but the pixel clock setup by the firmware doesn't
work, and it's Raspberry Pi specific anyway. The only conflicts we
should have with the firmware would be if we made firmware calls that
result in clock management (like opening firmware V3D or ISP access,
which we don't support in upstream), or on hardware over-thermal or
under-voltage (when the firmware would rewrite PLLB to take the ARM
out of overclock). If that happens, our cached .recalc_rate() results
would be incorrect, but that's no worse than our current state where
we used fixed clocks.
The existing fixed clocks in the code are left in place to provide
backwards compatibility with old device tree files.
Signed-off-by: Eric Anholt <eric@anholt.net>
Tested-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
clk-bcm2835.c predates the drivers under bcm/, but all the new BCM
drivers are going in there so let's follow them.
Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Phil Elwell