hw/misc/pca9552: Trace GPIO High/Low events
Add a trivial representation of the PCA9552 GPIOs. Example booting obmc-phosphor-image: $ qemu-system-arm -M witherspoon-bmc -trace pca955x_gpio_status 1592689902.327837:pca955x_gpio_status pca-unspecified GPIOs 0-15 [*...............] 1592689902.329934:pca955x_gpio_status pca-unspecified GPIOs 0-15 [**..............] 1592689902.330717:pca955x_gpio_status pca-unspecified GPIOs 0-15 [***.............] 1592689902.331431:pca955x_gpio_status pca-unspecified GPIOs 0-15 [****............] 1592689902.332163:pca955x_gpio_status pca-unspecified GPIOs 0-15 [****.........*..] 1592689902.332888:pca955x_gpio_status pca-unspecified GPIOs 0-15 [****.........**.] 1592689902.333629:pca955x_gpio_status pca-unspecified GPIOs 0-15 [****.........***] 1592690032.793289:pca955x_gpio_status pca-unspecified GPIOs 0-15 [****.........*.*] 1592690033.303163:pca955x_gpio_status pca-unspecified GPIOs 0-15 [****.........***] 1592690033.812962:pca955x_gpio_status pca-unspecified GPIOs 0-15 [****.........*.*] 1592690034.323234:pca955x_gpio_status pca-unspecified GPIOs 0-15 [****.........***] 1592690034.832922:pca955x_gpio_status pca-unspecified GPIOs 0-15 [****.........*.*] We notice the GPIO #14 (front-power LED) starts to blink. This LED is described in the witherspoon device-tree [*]: front-power { retain-state-shutdown; default-state = "keep"; gpios = <&pca0 14 GPIO_ACTIVE_LOW>; }; [*] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/aspeed-bmc-opp-witherspoon.dts?id=b1f9be9392f0#n140Suggested-by: NCédric Le Goater <clg@kaod.org> Reviewed-by: NCédric Le Goater <clg@kaod.org> Signed-off-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org> Tested-by: NCédric Le Goater <clg@kaod.org> Message-id: 20200623072723.6324-7-f4bug@amsat.org Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
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