Until now (gx and axg), the mpll setting on boot (whatever the
bootloader) was good enough to generate a clean fractional division.
It is not the case on the g12a. While moving away from the vendor u-boot,
it was noticed the fractional part of the divider was no longer applied.
Like on the pll, some magic settings need to applied on the mpll
register.
This change adds the ability to do that on the mpll driver.
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
The bit 'SSEN' available on some MPLL DSS outputs is not related to the
fractional part of the divider but to the function called
'Spread Spectrum'.
This function might be used to solve EM issues by adding a jitter on
clock signal. This widens the signal spectrum and weakens the peaks in it.
While spread spectrum might be useful for some application, it is
problematic for others, such as audio.
This patch introduce a new flag to the MPLL driver to enable (or not) the
spread spectrum function.
Fixes: 1f737ffa13 ("clk: meson: mpll: fix mpll0 fractional part ignored")
Tested-by: Martin Blumenstingl<martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Initially, the meson clock directory only hosted 2 controllers drivers,
for meson8 and gxbb. At the time, both used the same set of clock drivers
so managing the dependencies was not a big concern.
Since this ancient time, entropy did its job, controllers with different
requirement and specific clock drivers have been added. Unfortunately, we
did not do a great job at managing the dependencies between the
controllers and the different clock drivers. Some drivers, such as
clk-phase or vid-pll-div, are compiled even if they are useless on the
target (meson8). As we are adding new controllers, we need to be able to
pick a driver w/o pulling the whole thing.
The patch aims to clean things up by:
* providing a dedicated CONFIG_ for each clock drivers
* allowing clock drivers to be compiled as a modules, if possible
* stating explicitly which drivers are required by each controller.
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lkml.kernel.org/r/20190201125841.26785-5-jbrunet@baylibre.com
Allow the mpll driver to round the requested rate up if
CLK_MESON_MPLL_ROUND_CLOSEST is set and it provides a rate closer to the
requested rate.
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Martin Blumenstingl<martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Replace every license notices in drivers/clk/meson by SPDX license
identifiers, as described in license-rules.rst
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
The mpll clock is a kind of fractional divider which can gate.
When the RW operation have been added, enable/disable ops have been
mistakenly inserted in this driver. These ops are essentially a
poor copy/paste of the generic gate ops.
This change removes the gate ops from the mpll driver and inserts a
generic gate clock on each mpll divider, simplifying the mpll
driver and reducing code duplication.
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Rework meson mpll driver to use clk_regmap and move meson8b, gxbb
and axg clocks using meson_clk_mpll to clk_regmap
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
On axg, the rate of the mpll is stuck as if sdm value was 4 and could not
change (expect for mpll2 strangely). Looking at the vendor kernel, it
turns out a new magic bit from the undocumented HHI_PLL_TOP_MISC register
is required.
Setting this bit solves the problem and the mpll rates are back to normal
Fixes: 78b4af312f ("clk: meson-axg: add clock controller drivers")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
"rem * SDM_DEN" can easily overflow on the 32-bit Meson8 and Meson8b
SoCs if the "remainder" (after the division operation) is greater than
262143Hz. This is likely to happen since the input clock for the MPLLs
on Meson8 and Meson8b is "fixed_pll", which is running at a rate of
2550MHz.
One example where this was observed to be problematic was the Ethernet
clock calculation (which takes MPLL2 as input). When requesting a rate
of 125MHz there is a remainder of 2500000Hz.
The resulting MPLL2 rate before this patch was 127488329Hz.
The resulting MPLL2 rate after this patch is 124999103Hz.
Commit b609338b26 ("clk: meson: mpll: use 64bit math in
rate_from_params") already fixed a similar issue in rate_from_params.
Fixes: 007e6e5c5f ("clk: meson: mpll: add rw operation")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
mpll0 clock is special compared to the other mplls. It needs another
bit (ssen) to be set to activate the fractional part the mpll divider
Fixes: 007e6e5c5f ("clk: meson: mpll: add rw operation")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
On Meson8b the MPLL parent clock (fixed_pll) has a rate of 2550MHz.
Multiplying this with SDM_DEN results in a value greater than 32bits.
This is not a problem on the 64bit Meson GX SoCs, but it may result in
undefined behavior on the older 32bit Meson8b SoC.
While rate_from_params was only introduced recently to make the math
reusable from _round_rate and _recalc_rate the original bug exists much
longer.
Fixes: 1c50da4f27 ("clk: meson: add mpll support")
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
[as discussed on the ml, use DIV_ROUND_UP_ULL]
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
According to the public datasheet all register bits in HHI_MPLL_CNTL7,
HHI_MPLL_CNTL8 and HHI_MPLL_CNTL9 default to zero. On all GX SoCs these
seem to be initialized by the bootloader to some default value.
However, on my Meson8 board they are not initialized, leading to a
division by zero in rate_from_params as the math is:
(parent_rate * SDM_DEN) / ((SDM_DEN * 0) + 0)
According to the datasheet, the minimum n2 value is 4. The rate provided
by the clock when n2 is less than this minimum is unpredictable. In such
case, we report an error.
Although the rate_from_params function was only introduced recently the
original bug has been there for much longer. It was only exposed
recently when the MPLL clocks were added to the Meson8b clock driver.
Fixes: 1c50da4f27 ("clk: meson: add mpll support")
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Gxbb datasheet says N2 maximum value is 127 but the register field is
9 bits wide, the maximum value should 511.
Test shows value greater than 127, all the way to 511, works well
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20170309104154.28295-9-jbrunet@baylibre.com
This patch adds new callbacks to the meson-mpll driver to control
and set the pll rate. For this, we also need to add the enable bit and
sdm enable bit. The corresponding parameters are added to mpll data
structure.
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20170309104154.28295-6-jbrunet@baylibre.com
MPLLs are adjustable rate clocks derived from PLLs. On both Meson8b and
GXBB they appear to be only derived from fixed_pll.
Add support for these clock types so that they can be added to their
respective drivers.
Tested-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Jerome Brunet
Martin Blumenstingl
Michael Turquette