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hw/misc/pca9552: Trace GPIO High/Low events

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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#n140

Suggested-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Cédric Le Goater <clg@kaod.org>
Message-id: 20200623072723.6324-7-f4bug@amsat.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Philippe Mathieu-Daudé 2020-06-23 09:27:20 +02:00 committed by Peter Maydell
parent 2df252d879
commit b989b89f67
2 changed files with 42 additions and 0 deletions
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39
hw/misc/pca9552.c
View file

@ -13,12 +13,14 @@
#include "qemu/osdep.h"
#include "qemu/log.h"
#include "qemu/module.h"
#include "qemu/bitops.h"
#include "hw/qdev-properties.h"
#include "hw/misc/pca9552.h"
#include "hw/misc/pca9552_regs.h"
#include "migration/vmstate.h"
#include "qapi/error.h"
#include "qapi/visitor.h"
#include "trace.h"
typedef struct PCA955xClass {
/*< private >*/
@ -49,6 +51,39 @@ static uint8_t pca955x_pin_get_config(PCA955xState *s, int pin)
return extract32(s->regs[reg], shift, 2);
}
/* Return INPUT status (bit #N belongs to GPIO #N) */
static uint16_t pca955x_pins_get_status(PCA955xState *s)
{
return (s->regs[PCA9552_INPUT1] << 8) | s->regs[PCA9552_INPUT0];
}
static void pca955x_display_pins_status(PCA955xState *s,
uint16_t previous_pins_status)
{
PCA955xClass *k = PCA955X_GET_CLASS(s);
uint16_t pins_status, pins_changed;
int i;
pins_status = pca955x_pins_get_status(s);
pins_changed = previous_pins_status ^ pins_status;
if (!pins_changed) {
return;
}
if (trace_event_get_state_backends(TRACE_PCA955X_GPIO_STATUS)) {
char *buf = g_newa(char, k->pin_count + 1);
for (i = 0; i < k->pin_count; i++) {
if (extract32(pins_status, i, 1)) {
buf[i] = '*';
} else {
buf[i] = '.';
}
}
buf[i] = '\0';
trace_pca955x_gpio_status(s->description, buf);
}
}
static void pca955x_update_pin_input(PCA955xState *s)
{
PCA955xClass *k = PCA955X_GET_CLASS(s);
@ -98,6 +133,8 @@ static uint8_t pca955x_read(PCA955xState *s, uint8_t reg)
static void pca955x_write(PCA955xState *s, uint8_t reg, uint8_t data)
{
uint16_t pins_status;
switch (reg) {
case PCA9552_PSC0:
case PCA9552_PWM0:
@ -110,8 +147,10 @@ static void pca955x_write(PCA955xState *s, uint8_t reg, uint8_t data)
case PCA9552_LS1:
case PCA9552_LS2:
case PCA9552_LS3:
pins_status = pca955x_pins_get_status(s);
s->regs[reg] = data;
pca955x_update_pin_input(s);
pca955x_display_pins_status(s, pins_status);
break;
case PCA9552_INPUT0:

3
hw/misc/trace-events
View file

@ -209,3 +209,6 @@ via1_adb_poll(uint8_t data, const char *vadbint, int status, int index, int size
# grlib_ahb_apb_pnp.c
grlib_ahb_pnp_read(uint64_t addr, uint32_t value) "AHB PnP read addr:0x%03"PRIx64" data:0x%08x"
grlib_apb_pnp_read(uint64_t addr, uint32_t value) "APB PnP read addr:0x%03"PRIx64" data:0x%08x"
# pca9552.c
pca955x_gpio_status(const char *description, const char *buf) "%s GPIOs 0-15 [%s]"