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>
The CPRMAN PLLs generate a clock based on a prescaler, a multiplier and
a divider. The prescaler doubles the parent (xosc) frequency, then the
multiplier/divider are applied. The multiplier has an integer and a
fractional part.
This commit also implements the CPRMAN CM_LOCK register. This register
reports which PLL is currently locked. We consider a PLL has being
locked as soon as it is enabled (on real hardware, there is a delay
after turning a PLL on, for it to stabilize).
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>
Luc Michel