From: Luc Michel <luc.michel@greensocs.com>
To: "Philippe Mathieu-Daudé" <f4bug@amsat.org>, qemu-devel@nongnu.org
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
"Daniel P. Berrangé" <berrange@redhat.com>,
"Eduardo Habkost" <ehabkost@redhat.com>,
"Andrew Jeffery" <andrew@aj.id.au>,
qemu-arm@nongnu.org, "Joel Stanley" <joel@jms.id.au>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Cédric Le Goater" <clg@kaod.org>
Subject: Re: [PATCH v6 2/7] hw/misc/led: Allow connecting from GPIO output
Date: Mon, 14 Sep 2020 09:18:49 +0200 [thread overview]
Message-ID: <f092c9df-db98-41fc-4ba2-34d6eafc095c@greensocs.com> (raw)
In-Reply-To: <20200912134041.946260-3-f4bug@amsat.org>
On 9/12/20 3:40 PM, Philippe Mathieu-Daudé wrote:
> Some devices expose GPIO lines.
>
> Add a GPIO qdev input to our LED device, so we can
> connect a GPIO output using qdev_connect_gpio_out().
>
> When used with GPIOs, the intensity can only be either
> minium or maximum. This depends of the polarity of the
> GPIO (which can be inverted).
> Declare the GpioPolarity type to model the polarity.
>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Luc Michel <luc.michel@greensocs.com>
> ---
> include/hw/misc/led.h | 10 ++++++++++
> include/hw/qdev-core.h | 16 ++++++++++++++++
> hw/misc/led.c | 17 ++++++++++++++++-
> 3 files changed, 42 insertions(+), 1 deletion(-)
>
> diff --git a/include/hw/misc/led.h b/include/hw/misc/led.h
> index 286d37c75c1..aa359b87c20 100644
> --- a/include/hw/misc/led.h
> +++ b/include/hw/misc/led.h
> @@ -9,6 +9,7 @@
> #define HW_MISC_LED_H
>
> #include "qom/object.h"
> +#include "hw/qdev-core.h"
>
> #define TYPE_LED "led"
>
> @@ -37,10 +38,17 @@ struct LEDState {
> /* Public */
>
> uint8_t intensity_percent;
> + qemu_irq irq;
>
> /* Properties */
> char *description;
> char *color;
> + /*
> + * Determines whether a GPIO is using a positive (active-high)
> + * logic (when used with GPIO, the intensity at reset is related
> + * to the GPIO polarity).
> + */
> + bool gpio_active_high;
> };
> typedef struct LEDState LEDState;
> DECLARE_INSTANCE_CHECKER(LEDState, LED, TYPE_LED)
> @@ -72,6 +80,7 @@ void led_set_state(LEDState *s, bool is_emitting);
> /**
> * led_create_simple: Create and realize a LED device
> * @parentobj: the parent object
> + * @gpio_polarity: GPIO polarity
> * @color: color of the LED
> * @description: description of the LED (optional)
> *
> @@ -81,6 +90,7 @@ void led_set_state(LEDState *s, bool is_emitting);
> * Returns: The newly allocated and instantiated LED object.
> */
> LEDState *led_create_simple(Object *parentobj,
> + GpioPolarity gpio_polarity,
> LEDColor color,
> const char *description);
>
> diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
> index e025ba9653f..ec1f1efc37b 100644
> --- a/include/hw/qdev-core.h
> +++ b/include/hw/qdev-core.h
> @@ -423,6 +423,22 @@ void qdev_simple_device_unplug_cb(HotplugHandler *hotplug_dev,
> void qdev_machine_creation_done(void);
> bool qdev_machine_modified(void);
>
> +/**
> + * GpioPolarity: Polarity of a GPIO line
> + *
> + * GPIO lines use either positive (active-high) logic,
> + * or negative (active-low) logic.
> + *
> + * In active-high logic (%GPIO_POLARITY_ACTIVE_HIGH), a pin is
> + * active when the voltage on the pin is high (relative to ground);
> + * whereas in active-low logic (%GPIO_POLARITY_ACTIVE_LOW), a pin
> + * is active when the voltage on the pin is low (or grounded).
> + */
> +typedef enum {
> + GPIO_POLARITY_ACTIVE_LOW,
> + GPIO_POLARITY_ACTIVE_HIGH
> +} GpioPolarity;
> +
> /**
> * qdev_get_gpio_in: Get one of a device's anonymous input GPIO lines
> * @dev: Device whose GPIO we want
> diff --git a/hw/misc/led.c b/hw/misc/led.c
> index 1e2f49c5710..c5fa09a613a 100644
> --- a/hw/misc/led.c
> +++ b/hw/misc/led.c
> @@ -10,6 +10,7 @@
> #include "migration/vmstate.h"
> #include "hw/qdev-properties.h"
> #include "hw/misc/led.h"
> +#include "hw/irq.h"
> #include "trace.h"
>
> #define LED_INTENSITY_PERCENT_MAX 100
> @@ -53,11 +54,19 @@ void led_set_state(LEDState *s, bool is_emitting)
> led_set_intensity(s, is_emitting ? LED_INTENSITY_PERCENT_MAX : 0);
> }
>
> +static void led_set_state_gpio_handler(void *opaque, int line, int new_state)
> +{
> + LEDState *s = LED(opaque);
> +
> + assert(line == 0);
> + led_set_state(s, !!new_state != s->gpio_active_high);
> +}
> +
> static void led_reset(DeviceState *dev)
> {
> LEDState *s = LED(dev);
>
> - led_set_state(s, false);
> + led_set_state(s, s->gpio_active_high);
> }
>
> static const VMStateDescription vmstate_led = {
> @@ -84,11 +93,14 @@ static void led_realize(DeviceState *dev, Error **errp)
> if (s->description == NULL) {
> s->description = g_strdup("n/a");
> }
> +
> + qdev_init_gpio_in(DEVICE(s), led_set_state_gpio_handler, 1);
> }
>
> static Property led_properties[] = {
> DEFINE_PROP_STRING("color", LEDState, color),
> DEFINE_PROP_STRING("description", LEDState, description),
> + DEFINE_PROP_BOOL("gpio-active-high", LEDState, gpio_active_high, true),
> DEFINE_PROP_END_OF_LIST(),
> };
>
> @@ -119,6 +131,7 @@ static void led_register_types(void)
> type_init(led_register_types)
>
> LEDState *led_create_simple(Object *parentobj,
> + GpioPolarity gpio_polarity,
> LEDColor color,
> const char *description)
> {
> @@ -126,6 +139,8 @@ LEDState *led_create_simple(Object *parentobj,
> DeviceState *dev;
>
> dev = qdev_new(TYPE_LED);
> + qdev_prop_set_bit(dev, "gpio-active-high",
> + gpio_polarity == GPIO_POLARITY_ACTIVE_HIGH);
> qdev_prop_set_string(dev, "color", led_color_name[color]);
> if (!description) {
> static unsigned undescribed_led_id;
>
next prev parent reply other threads:[~2020-09-14 7:23 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-12 13:40 [PATCH v6 0/7] hw/misc: Add LED device Philippe Mathieu-Daudé
2020-09-12 13:40 ` [PATCH v6 1/7] hw/misc/led: Add a " Philippe Mathieu-Daudé
2020-09-12 13:40 ` [PATCH v6 2/7] hw/misc/led: Allow connecting from GPIO output Philippe Mathieu-Daudé
2020-09-14 1:45 ` Richard Henderson
2020-09-14 1:46 ` Richard Henderson
2020-09-14 7:18 ` Luc Michel [this message]
2020-09-12 13:40 ` [PATCH v6 3/7] hw/misc/led: Emit a trace event when LED intensity has changed Philippe Mathieu-Daudé
2020-09-12 13:40 ` [PATCH v6 4/7] hw/arm/aspeed: Add the 3 front LEDs drived by the PCA9552 #1 Philippe Mathieu-Daudé
2020-09-15 5:51 ` Cédric Le Goater
2020-09-12 13:40 ` [PATCH v6 5/7] hw/misc/mps2-fpgaio: Use the LED device Philippe Mathieu-Daudé
2020-09-14 7:19 ` Luc Michel
2020-09-12 13:40 ` [PATCH v6 6/7] hw/misc/mps2-scc: " Philippe Mathieu-Daudé
2020-09-14 7:19 ` Luc Michel
2020-09-12 13:40 ` [PATCH v6 7/7] hw/arm/tosa: Replace fprintf() calls by LED devices Philippe Mathieu-Daudé
2020-09-12 13:46 ` [PATCH v6 0/7] hw/misc: Add LED device no-reply
2020-09-19 12:30 ` Philippe Mathieu-Daudé
2020-10-16 15:29 ` Philippe Mathieu-Daudé
2020-10-26 22:00 ` Philippe Mathieu-Daudé
2020-11-02 9:55 ` Cédric Le Goater
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