This simple mux sits between the PLL channels and the DSI0E and DSI0P
clock muxes. This mux selects between PLLA-DSI0 and PLLD-DSI0 channel
and outputs the selected signal to source number 4 of DSI0E/P clock
muxes. It is controlled by the cm_dsi0hsck register.
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Luc Michel <luc@lmichel.fr>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The clock multiplexers are the last clock stage in the CPRMAN. Each mux
outputs one clock signal that goes out of the CPRMAN to the SoC
peripherals.
Each mux has at most 10 sources. The sources 0 to 3 are common to all
muxes. They are:
0. ground (no clock signal)
1. the main oscillator (xosc)
2. "test debug 0" clock
3. "test debug 1" clock
Test debug 0 and 1 are actual clock muxes that can be used as sources to
other muxes (for debug purpose).
Sources 4 to 9 are mux specific and can be unpopulated (grounded). Those
sources are fed by the PLL channels outputs.
One corner case exists for DSI0E and DSI0P muxes. They have their source
number 4 connected to an intermediate multiplexer that can select
between PLLA-DSI0 and PLLD-DSI0 channel. This multiplexer is called
DSI0HSCK and is not a clock mux as such. It is really a simple mux from
the hardware point of view (see https://elinux.org/The_Undocumented_Pi).
This mux is not implemented in this commit.
Note that there is some muxes for which sources are unknown (because of
a lack of documentation). For those cases all the sources are connected
to ground in this implementation.
Each clock mux output is exported by the CPRMAN at the qdev level,
adding the suffix '-out' to the mux name to form the output clock name.
(E.g. the 'uart' mux sees its output exported as 'uart-out' at the
CPRMAN level.)
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Luc Michel <luc@lmichel.fr>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
PLLs are composed of multiple channels. Each channel outputs one clock
signal. They are modeled as one device taking the PLL generated clock as
input, and outputting a new clock.
A channel shares the CM register with its parent PLL, and has its own
A2W_CTRL register. A write to the CM register will trigger an update of
the PLL and all its channels, while a write to an A2W_CTRL channel
register will update the required channel only.
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Luc Michel <luc@lmichel.fr>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
There are 5 PLLs in the CPRMAN, namely PLL A, C, D, H and B. All of them
take the xosc clock as input and produce a new clock.
This commit adds a skeleton implementation for the PLLs as sub-devices
of the CPRMAN. The PLLs are instantiated and connected internally to the
main oscillator.
Each PLL has 6 registers : CM, A2W_CTRL, A2W_ANA[0,1,2,3], A2W_FRAC. A
write to any of them triggers a call to the (not yet implemented)
pll_update function.
If the main oscillator changes frequency, an update is also triggered.
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Luc Michel <luc@lmichel.fr>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The BCM2835 CPRMAN is the clock manager of the SoC. It is composed of a
main oscillator, and several sub-components (PLLs, multiplexers, ...) to
generate the BCM2835 clock tree.
This commit adds a skeleton of the CPRMAN, with a dummy register
read/write implementation. It embeds the main oscillator (xosc) from
which all the clocks will be derived.
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Luc Michel <luc@lmichel.fr>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
