diff mbox series

[1/3] hw/gpio: Implement STM32L4x5 GPIO

Message ID 20240122092005.30556-2-ines.varhol@telecom-paris.fr (mailing list archive)
State New, archived
Headers show
Series Add device STM32L4x5 GPIO | expand

Commit Message

Inès Varhol Jan. 22, 2024, 9:18 a.m. UTC
Features supported :
- the 8 STM32L4x5 GPIOs are initialized with their reset values
    (except IDR, see below)
- input mode : setting a pin in input mode "externally" (using input
    irqs) results in an out irq (transmitted to SYSCFG)
- output mode : setting a bit in ODR sets the corresponding out irq
    (if this line is configured in output mode)
- pull-up, pull-down
- push-pull, open-drain

Difference with the real GPIOs :
- Alternate Function and Analog mode aren't implemented :
    pins in AF/Analog behave like pins in input mode
- floating pins stay at their last value
- register IDR reset values differ from the real one :
    values are coherent with the other registers reset values
    and the fact that AF/Analog modes aren't implemented
- setting I/O output speed isn't supported
- locking port bits isn't supported
- ADC function isn't supported
- GPIOH has 16 pins instead of 2 pins
- writing to registers LCKR, AFRL, AFRH and ASCR is ineffective

Signed-off-by: Arnaud Minier <arnaud.minier@telecom-paris.fr>
Signed-off-by: Inès Varhol <ines.varhol@telecom-paris.fr>
---
 MAINTAINERS                        |   1 +
 docs/system/arm/b-l475e-iot01a.rst |   2 +-
 hw/gpio/Kconfig                    |   3 +
 hw/gpio/meson.build                |   1 +
 hw/gpio/stm32l4x5_gpio.c           | 537 +++++++++++++++++++++++++++++
 hw/gpio/trace-events               |   6 +
 include/hw/gpio/stm32l4x5_gpio.h   |  80 +++++
 7 files changed, 629 insertions(+), 1 deletion(-)
 create mode 100644 hw/gpio/stm32l4x5_gpio.c
 create mode 100644 include/hw/gpio/stm32l4x5_gpio.h

Comments

Philippe Mathieu-Daudé Jan. 22, 2024, 11:32 a.m. UTC | #1
Hello Inès,

On 22/1/24 10:18, Inès Varhol wrote:
> Features supported :
> - the 8 STM32L4x5 GPIOs are initialized with their reset values
>      (except IDR, see below)
> - input mode : setting a pin in input mode "externally" (using input
>      irqs) results in an out irq (transmitted to SYSCFG)
> - output mode : setting a bit in ODR sets the corresponding out irq
>      (if this line is configured in output mode)
> - pull-up, pull-down
> - push-pull, open-drain
> 
> Difference with the real GPIOs :
> - Alternate Function and Analog mode aren't implemented :
>      pins in AF/Analog behave like pins in input mode
> - floating pins stay at their last value
> - register IDR reset values differ from the real one :
>      values are coherent with the other registers reset values
>      and the fact that AF/Analog modes aren't implemented
> - setting I/O output speed isn't supported
> - locking port bits isn't supported
> - ADC function isn't supported
> - GPIOH has 16 pins instead of 2 pins
> - writing to registers LCKR, AFRL, AFRH and ASCR is ineffective
> 
> Signed-off-by: Arnaud Minier <arnaud.minier@telecom-paris.fr>
> Signed-off-by: Inès Varhol <ines.varhol@telecom-paris.fr>
> ---
>   MAINTAINERS                        |   1 +
>   docs/system/arm/b-l475e-iot01a.rst |   2 +-
>   hw/gpio/Kconfig                    |   3 +
>   hw/gpio/meson.build                |   1 +
>   hw/gpio/stm32l4x5_gpio.c           | 537 +++++++++++++++++++++++++++++
>   hw/gpio/trace-events               |   6 +
>   include/hw/gpio/stm32l4x5_gpio.h   |  80 +++++
>   7 files changed, 629 insertions(+), 1 deletion(-)
>   create mode 100644 hw/gpio/stm32l4x5_gpio.c
>   create mode 100644 include/hw/gpio/stm32l4x5_gpio.h


> +static void stm32l4x5_gpio_a_class_init(ObjectClass *klass, void *data)
> +{
> +    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
> +
> +    sc->moder_reset = 0xABFFFFFF;
> +    sc->ospeedr_reset = 0x0C000000;
> +    sc->pupdr_reset = 0x64000000;
> +}
> +
> +static void stm32l4x5_gpio_b_class_init(ObjectClass *klass, void *data)
> +{
> +    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
> +
> +    sc->moder_reset = 0xFFFFFEBF;
> +    sc->ospeedr_reset = 0x00000000;
> +    sc->pupdr_reset = 0x00000100;
> +}
> +
> +static void stm32l4x5_gpio_c_class_init(ObjectClass *klass, void *data)
> +{
> +    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
> +
> +    sc->moder_reset = 0xFFFFFFFF;
> +    sc->ospeedr_reset = 0x00000000;
> +    sc->pupdr_reset = 0x00000000;
> +}
> +
> +static void stm32l4x5_gpio_d_class_init(ObjectClass *klass, void *data)
> +{
> +    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
> +
> +    sc->moder_reset = 0xFFFFFFFF;
> +    sc->ospeedr_reset = 0x00000000;
> +    sc->pupdr_reset = 0x00000000;
> +}
> +
> +static void stm32l4x5_gpio_e_class_init(ObjectClass *klass, void *data)
> +{
> +    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
> +
> +    sc->moder_reset = 0xFFFFFFFF;
> +    sc->ospeedr_reset = 0x00000000;
> +    sc->pupdr_reset = 0x00000000;
> +}
> +
> +static void stm32l4x5_gpio_f_class_init(ObjectClass *klass, void *data)
> +{
> +    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
> +
> +    sc->moder_reset = 0xFFFFFFFF;
> +    sc->ospeedr_reset = 0x00000000;
> +    sc->pupdr_reset = 0x00000000;
> +}
> +
> +static void stm32l4x5_gpio_g_class_init(ObjectClass *klass, void *data)
> +{
> +    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
> +
> +    sc->moder_reset = 0xFFFFFFFF;
> +    sc->ospeedr_reset = 0x00000000;
> +    sc->pupdr_reset = 0x00000000;
> +}
> +
> +static void stm32l4x5_gpio_h_class_init(ObjectClass *klass, void *data)
> +{
> +    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
> +
> +    sc->moder_reset = 0x0000000F;
> +    sc->ospeedr_reset = 0x00000000;
> +    sc->pupdr_reset = 0x00000000;
> +}
> +
> +static const TypeInfo stm32l4x5_gpio_types[] = {
> +    {
> +        .name = TYPE_STM32L4X5_GPIO,
> +        .parent = TYPE_SYS_BUS_DEVICE,
> +        .instance_size = sizeof(Stm32l4x5GpioState),
> +        .instance_init = stm32l4x5_gpio_init,
> +        .class_size     = sizeof(Stm32l4x5GpioClass),
> +        .class_init = stm32l4x5_gpio_class_init,
> +        .abstract = true,
> +    }, {
> +        .name = TYPE_STM32L4X5_GPIO_A,
> +        .parent = TYPE_STM32L4X5_GPIO,
> +        .class_init = stm32l4x5_gpio_a_class_init,
> +    }, {
> +        .name = TYPE_STM32L4X5_GPIO_B,
> +        .parent = TYPE_STM32L4X5_GPIO,
> +        .class_init = stm32l4x5_gpio_b_class_init,
> +    }, {
> +        .name = TYPE_STM32L4X5_GPIO_C,
> +        .parent = TYPE_STM32L4X5_GPIO,
> +        .class_init = stm32l4x5_gpio_c_class_init,
> +    }, {
> +        .name = TYPE_STM32L4X5_GPIO_D,
> +        .parent = TYPE_STM32L4X5_GPIO,
> +        .class_init = stm32l4x5_gpio_d_class_init,
> +    }, {

My understanding is the same GPIO block is used for the STM32L4*
family, and the reset values are specific to each SoC.

Therefore I'd keep a generic GPIO model in this file, and set the
reset values in stm32l4x5_soc.c, likely stm32l4x5_soc_realize().

Something like:

static const struct {
     uint32_t moder;
     uint32_t ospeedr;
     uint32_t pupdr;
} stm32l4x5_gpio_initval[NUM_GPIOS] = {
     { 0xABFFFFFF, 0x0C000000, 0x64000000 },
     { 0xFFFFFEBF, 0x00000000, 0x00000100 },
     { 0xFFFFFFFF, 0x00000000, 0x00000000 },
     ...
};

   for (unsigned i = 0; i < NUM_GPIOS; i++) {
       DeviceState *dev = DEVICE(&s->gpio[i]);
       g_autofree char *name = g_strdup_printf("%c", 'A' + i);

       qdev_prop_set_string(dev, "name", name);
       qdev_prop_set_uint32(dev, "mode-reset",
                            stm32l4x5_gpio_initval[i].moder);
       qdev_prop_set_uint32(dev, "ospeed-reset",
                            stm32l4x5_gpio_initval[i].ospeedr);
       qdev_prop_set_uint32(dev, "pupd-reset",
                            stm32l4x5_gpio_initval[i].pupdr);
       ...
   }

(Having "mode-reset", "ospeed-reset", "pupd-reset" exposed as
  DEFINE_PROP_UINT32() properties).

Regards,

Phil.
Philippe Mathieu-Daudé Jan. 22, 2024, 11:37 a.m. UTC | #2
Hi Inès,

On 22/1/24 10:18, Inès Varhol wrote:
> Features supported :
> - the 8 STM32L4x5 GPIOs are initialized with their reset values
>      (except IDR, see below)
> - input mode : setting a pin in input mode "externally" (using input
>      irqs) results in an out irq (transmitted to SYSCFG)
> - output mode : setting a bit in ODR sets the corresponding out irq
>      (if this line is configured in output mode)
> - pull-up, pull-down
> - push-pull, open-drain
> 
> Difference with the real GPIOs :
> - Alternate Function and Analog mode aren't implemented :
>      pins in AF/Analog behave like pins in input mode
> - floating pins stay at their last value
> - register IDR reset values differ from the real one :
>      values are coherent with the other registers reset values
>      and the fact that AF/Analog modes aren't implemented
> - setting I/O output speed isn't supported
> - locking port bits isn't supported
> - ADC function isn't supported
> - GPIOH has 16 pins instead of 2 pins
> - writing to registers LCKR, AFRL, AFRH and ASCR is ineffective
> 
> Signed-off-by: Arnaud Minier <arnaud.minier@telecom-paris.fr>
> Signed-off-by: Inès Varhol <ines.varhol@telecom-paris.fr>
> ---
>   MAINTAINERS                        |   1 +
>   docs/system/arm/b-l475e-iot01a.rst |   2 +-
>   hw/gpio/Kconfig                    |   3 +
>   hw/gpio/meson.build                |   1 +
>   hw/gpio/stm32l4x5_gpio.c           | 537 +++++++++++++++++++++++++++++
>   hw/gpio/trace-events               |   6 +
>   include/hw/gpio/stm32l4x5_gpio.h   |  80 +++++
>   7 files changed, 629 insertions(+), 1 deletion(-)
>   create mode 100644 hw/gpio/stm32l4x5_gpio.c
>   create mode 100644 include/hw/gpio/stm32l4x5_gpio.h


> +#define GPIO_MODER 0x00
> +#define GPIO_OTYPER 0x04
> +#define GPIO_OSPEEDR 0x08
> +#define GPIO_PUPDR 0x0C
> +#define GPIO_IDR 0x10
> +#define GPIO_ODR 0x14
> +#define GPIO_BSRR 0x18
> +#define GPIO_LCKR 0x1C
> +#define GPIO_AFRL 0x20
> +#define GPIO_AFRH 0x24
> +#define GPIO_BRR 0x28
> +#define GPIO_ASCR 0x2C
> +/*
> + * DISCONNECTED_PINS isn't actually a GPIO register.
> + * It exists to ensure that :
> + * - push-pull output pins can't be set externally
> + * - open-drain output pins can only be externally set to 0
> + *
> + * This field is accessed for test purposes.
> + */
> +#define GPIO_DISCONNECTED_PINS 0x30

[*]

> +static void stm32l4x5_gpio_write(void *opaque, hwaddr addr,
> +                                 uint64_t val64, unsigned int size)
> +{
> +    Stm32l4x5GpioState *s = opaque;
> +
> +    uint32_t value = val64;
> +    trace_stm32l4x5_gpio_write(addr, val64);
> +
> +    switch (addr) {


> +    /* a tweak to enable the qtest checking disconnected pins */
> +    case GPIO_DISCONNECTED_PINS:
> +        disconnect_gpio_pins(s, value);
> +        return;
> +    default:
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: Bad offset 0x%" HWADDR_PRIx "\n", __func__, addr);
> +    }
> +}
> +
> +static uint64_t stm32l4x5_gpio_read(void *opaque, hwaddr addr,
> +                                    unsigned int size)
> +{
> +    Stm32l4x5GpioState *s = opaque;
> +
> +    trace_stm32l4x5_gpio_read(addr);
> +
> +    switch (addr) {


> +    /* a tweak to enable the qtest checking disconnected pins */
> +    case GPIO_DISCONNECTED_PINS:
> +        return s->disconnected_pins;
> +    default:
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: Bad offset 0x%" HWADDR_PRIx "\n", __func__, addr);
> +        return 0;
> +    }
> +}


> +static void stm32l4x5_gpio_init(Object *obj)
> +{
> +    Stm32l4x5GpioState *s = STM32L4X5_GPIO(obj);
> +
> +    memory_region_init_io(&s->mmio, obj, &stm32l4x5_gpio_ops, s,
> +                          TYPE_STM32L4X5_GPIO, 0x400);

This "testing purpose" [*] register is accessible by the guest, so
this isn't a faithful emulation of the device, and could possibly
lead to unexpected guest behavior.
You can store testing fields in the device state, but don't expose
the as register. Expose them as QOM/QDev properties and access them
with the QOM QTest helpers.

Regards,

Phil.

> +    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
> +
> +    qdev_init_gpio_out(DEVICE(obj), s->pin, GPIO_NUM_PINS);
> +    qdev_init_gpio_in(DEVICE(obj), stm32l4x5_gpio_set, GPIO_NUM_PINS);
> +
> +    s->clk = qdev_init_clock_in(DEVICE(s), "clk", NULL, s, 0);
> +}
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index c4085c32a7..269ed96052 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1131,6 +1131,7 @@  F: hw/arm/stm32l4x5_soc.c
 F: hw/misc/stm32l4x5_exti.c
 F: hw/misc/stm32l4x5_syscfg.c
 F: hw/misc/stm32l4x5_rcc.c
+F: hw/gpio/stm32l4x5_gpio.c
 F: include/hw/*/stm32l4x5_*.h
 
 B-L475E-IOT01A IoT Node
diff --git a/docs/system/arm/b-l475e-iot01a.rst b/docs/system/arm/b-l475e-iot01a.rst
index b857a56ca4..0afef8e4f4 100644
--- a/docs/system/arm/b-l475e-iot01a.rst
+++ b/docs/system/arm/b-l475e-iot01a.rst
@@ -18,6 +18,7 @@  Currently B-L475E-IOT01A machine's only supports the following devices:
 - STM32L4x5 EXTI (Extended interrupts and events controller)
 - STM32L4x5 SYSCFG (System configuration controller)
 - STM32L4x5 RCC (Reset and clock control)
+- STM32L4x5 GPIOs (General-purpose I/Os)
 
 Missing devices
 """""""""""""""
@@ -25,7 +26,6 @@  Missing devices
 The B-L475E-IOT01A does *not* support the following devices:
 
 - Serial ports (UART)
-- General-purpose I/Os (GPIO)
 - Analog to Digital Converter (ADC)
 - SPI controller
 - Timer controller (TIMER)
diff --git a/hw/gpio/Kconfig b/hw/gpio/Kconfig
index d2cf3accc8..712940b8e0 100644
--- a/hw/gpio/Kconfig
+++ b/hw/gpio/Kconfig
@@ -16,3 +16,6 @@  config GPIO_PWR
 
 config SIFIVE_GPIO
     bool
+
+config STM32L4X5_GPIO
+    bool
diff --git a/hw/gpio/meson.build b/hw/gpio/meson.build
index 066ea96480..8470ca1639 100644
--- a/hw/gpio/meson.build
+++ b/hw/gpio/meson.build
@@ -9,6 +9,7 @@  system_ss.add(when: 'CONFIG_IMX', if_true: files('imx_gpio.c'))
 system_ss.add(when: 'CONFIG_NPCM7XX', if_true: files('npcm7xx_gpio.c'))
 system_ss.add(when: 'CONFIG_NRF51_SOC', if_true: files('nrf51_gpio.c'))
 system_ss.add(when: 'CONFIG_OMAP', if_true: files('omap_gpio.c'))
+system_ss.add(when: 'CONFIG_STM32L4X5_SOC', if_true: files('stm32l4x5_gpio.c'))
 system_ss.add(when: 'CONFIG_RASPI', if_true: files('bcm2835_gpio.c'))
 system_ss.add(when: 'CONFIG_ASPEED_SOC', if_true: files('aspeed_gpio.c'))
 system_ss.add(when: 'CONFIG_SIFIVE_GPIO', if_true: files('sifive_gpio.c'))
diff --git a/hw/gpio/stm32l4x5_gpio.c b/hw/gpio/stm32l4x5_gpio.c
new file mode 100644
index 0000000000..35df427363
--- /dev/null
+++ b/hw/gpio/stm32l4x5_gpio.c
@@ -0,0 +1,537 @@ 
+/*
+ * STM32L4x5 GPIO (General Purpose Input/Ouput)
+ *
+ * Copyright (c) 2023 Arnaud Minier <arnaud.minier@telecom-paris.fr>
+ * Copyright (c) 2023 Inès Varhol <ines.varhol@telecom-paris.fr>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+/*
+ * The reference used is the STMicroElectronics RM0351 Reference manual
+ * for STM32L4x5 and STM32L4x6 advanced Arm ® -based 32-bit MCUs.
+ * https://www.st.com/en/microcontrollers-microprocessors/stm32l4x5/documentation.html
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "hw/gpio/stm32l4x5_gpio.h"
+#include "hw/irq.h"
+#include "hw/qdev-clock.h"
+#include "qapi/error.h"
+#include "migration/vmstate.h"
+#include "trace.h"
+
+#define GPIO_MODER 0x00
+#define GPIO_OTYPER 0x04
+#define GPIO_OSPEEDR 0x08
+#define GPIO_PUPDR 0x0C
+#define GPIO_IDR 0x10
+#define GPIO_ODR 0x14
+#define GPIO_BSRR 0x18
+#define GPIO_LCKR 0x1C
+#define GPIO_AFRL 0x20
+#define GPIO_AFRH 0x24
+#define GPIO_BRR 0x28
+#define GPIO_ASCR 0x2C
+/*
+ * DISCONNECTED_PINS isn't actually a GPIO register.
+ * It exists to ensure that :
+ * - push-pull output pins can't be set externally
+ * - open-drain output pins can only be externally set to 0
+ *
+ * This field is accessed for test purposes.
+ */
+#define GPIO_DISCONNECTED_PINS 0x30
+
+/* 0b11111111_11111111_00000000_00000000 */
+#define RESERVED_BITS_MASK 0xFFFF0000
+
+static void update_gpio_idr(Stm32l4x5GpioState *s);
+
+static void stm32l4x5_gpio_reset_hold(Object *obj)
+{
+    Stm32l4x5GpioState *s = STM32L4X5_GPIO(obj);
+    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_GET_CLASS(obj);
+
+    s->moder = sc->moder_reset;
+    s->otyper = 0x00000000;
+    s->ospeedr = sc->ospeedr_reset;
+    s->pupdr = sc->pupdr_reset;
+    s->idr = 0x00000000;
+    s->odr = 0x00000000;
+    s->lckr = 0x00000000;
+    s->afrl = 0x00000000;
+    s->afrh = 0x00000000;
+    s->ascr = 0x00000000;
+
+    s->disconnected_pins = 0xFFFF;
+    s->pins_connected_high = 0x0000;
+    update_gpio_idr(s);
+}
+
+static void stm32l4x5_gpio_set(void *opaque, int line, int level)
+{
+    Stm32l4x5GpioState *s = opaque;
+    /*
+     * The pin isn't set if line is configured in output mode
+     * except if level is 0 and the output is open-drain.
+     * This way there will be no short-circuit prone situations.
+     */
+    if ((extract32(s->moder, 2 * line, 2) == 1) &&
+        !((extract32(s->otyper, line, 1) == 1) &&
+          (level == 0))) {
+        qemu_log_mask(LOG_GUEST_ERROR, "Line %d can't be driven externally\n",
+                      line);
+        return;
+    }
+
+    s->disconnected_pins &= ~(1 << line);
+    if (level) {
+        s->pins_connected_high |= (1 << line);
+    } else {
+        s->pins_connected_high &= ~(1 << line);
+    }
+    trace_stm32l4x5_gpio_pins(s->disconnected_pins,
+                              s->pins_connected_high);
+    update_gpio_idr(s);
+}
+
+
+static void update_gpio_idr(Stm32l4x5GpioState *s)
+{
+    uint32_t new_idr_mask = 0;
+    uint32_t new_idr = s->odr;
+
+    for (int i = 0; i < 16; i++) {
+        /* output mode */
+        if (extract32(s->moder, 2 * i, 2) == 1) {
+            if (extract32(s->otyper, i, 1) == 0) {
+                /* push-pull */
+                new_idr_mask |= (1 << i);
+            } else if (!(s->odr & (1 << i))) {
+                /* open-drain ODR 0 */
+                new_idr_mask |= (1 << i);
+            } else if ((s->disconnected_pins & (1 << i)) &&
+                       (extract32(s->pupdr, 2 * i, 2) == 1)) {
+                /* open-drain pull-up ODR 1 with disconnected pin */
+                new_idr_mask |= (1 << i);
+            } else if ((s->disconnected_pins & (1 << i)) &&
+                       (extract32(s->pupdr, 2 * i, 2) == 2)) {
+                /* open-drain pull-down ODR 1 with disconnected pin */
+                new_idr_mask |= (1 << i);
+                new_idr &= ~(1 << i);
+            } else if (!(s->pins_connected_high & (1 << i))) {
+                /* open-drain ODR 1 with pin connected low */
+                new_idr_mask |= (1 << i);
+                new_idr &= ~(1 << i);
+            }
+            /*
+             * The only case left is for open-drain ODR 1
+             * with disconnected pin without pull-up or pull-down :
+             * the value is floating.
+             */
+        /* input or analog mode with connected pin */
+        } else if (!(s->disconnected_pins & (1 << i))) {
+            if (s->pins_connected_high & (1 << i)) {
+                /* pin high */
+                new_idr_mask |= (1 << i);
+                new_idr |= (1 << i);
+            } else {
+                /* pin low */
+                new_idr_mask |= (1 << i);
+                new_idr &= ~(1 << i);
+            }
+        /* input or analog mode with disconnected pin */
+        } else {
+            if (extract32(s->pupdr, 2 * i, 2) == 1) {
+                /* pull-up */
+                new_idr_mask |= (1 << i);
+                new_idr |= (1 << i);
+            } else if (extract32(s->pupdr, 2 * i, 2) == 2) {
+                /* pull-down */
+                new_idr_mask |= (1 << i);
+                new_idr &= ~(1 << i);
+            }
+            /*
+             * The only case left is for a disconnected pin
+             * without pull-up or pull-down :
+             * the value is floating.
+             */
+        }
+    }
+
+    uint32_t old_idr = s->idr;
+    s->idr = (old_idr & ~new_idr_mask) | (new_idr & new_idr_mask);
+    trace_stm32l4x5_gpio_update_idr(old_idr, s->idr);
+
+    for (int i = 0; i < 16; i++) {
+        if (new_idr_mask & (1 << i)) {
+            if ((new_idr & (1 << i)) > (old_idr & (1 << i))) {
+                qemu_irq_raise(s->pin[i]);
+            } else if ((new_idr & (1 << i)) < (old_idr & (1 << i))) {
+                qemu_irq_lower(s->pin[i]);
+            }
+        }
+    }
+}
+
+/*
+ * Return pins both configured in output mode
+ * and externally driven (except pins in open-drain
+ * mode externally set to 0).
+ */
+static uint32_t get_gpio_pins_to_disconnect(Stm32l4x5GpioState *s)
+{
+    uint32_t pins_to_disconnect = 0;
+    for (int i = 0; i < 16; i++) {
+        /* for each connected pin in output mode */
+        if ((~s->disconnected_pins & (1 << i)) &&
+            (extract32(s->moder, 2 * i, 2) == 1)) {
+            /* if either push-pull or high level */
+            if ((extract32(s->otyper, i, 1) == 0) ||
+                (extract16(s->pins_connected_high, i, 1)) == 1) {
+                pins_to_disconnect |= (1 << i);
+                qemu_log_mask(LOG_GUEST_ERROR,
+                              "Line %d can't be driven externally\n",
+                              i);
+            }
+        }
+    }
+    return pins_to_disconnect;
+}
+
+/*
+ * Set field `disconnected_pins` and call `update_gpio_idr()`
+ */
+static void disconnect_gpio_pins(Stm32l4x5GpioState *s, uint16_t lines)
+{
+    s->disconnected_pins |= lines;
+    trace_stm32l4x5_gpio_pins(s->disconnected_pins,
+                              s->pins_connected_high);
+    update_gpio_idr(s);
+}
+
+static void stm32l4x5_gpio_write(void *opaque, hwaddr addr,
+                                 uint64_t val64, unsigned int size)
+{
+    Stm32l4x5GpioState *s = opaque;
+
+    uint32_t value = val64;
+    trace_stm32l4x5_gpio_write(addr, val64);
+
+    switch (addr) {
+    case GPIO_MODER:
+        s->moder = value;
+        disconnect_gpio_pins(s, get_gpio_pins_to_disconnect(s));
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: Analog and AF modes aren't supported\n\
+                       Analog and AF mode behave like input mode\n",
+                      __func__);
+        return;
+    case GPIO_OTYPER:
+        s->otyper = value & ~RESERVED_BITS_MASK;
+        disconnect_gpio_pins(s, get_gpio_pins_to_disconnect(s));
+        return;
+    case GPIO_OSPEEDR:
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: Changing I/O output speed isn't supported\n\
+                       I/O speed is already maximal\n",
+                      __func__);
+        s->ospeedr = value;
+        return;
+    case GPIO_PUPDR:
+        s->pupdr = value;
+        update_gpio_idr(s);
+        return;
+    case GPIO_IDR:
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: GPIO->IDR is read-only\n",
+                      __func__);
+        return;
+    case GPIO_ODR:
+        s->odr = value & ~RESERVED_BITS_MASK;
+        update_gpio_idr(s);
+        return;
+    case GPIO_BSRR: {
+        uint32_t bits_to_reset = (value & RESERVED_BITS_MASK) >> 16;
+        uint32_t bits_to_set = value & ~RESERVED_BITS_MASK;
+        /* If both BSx and BRx are set, BSx has priority.*/
+        s->odr &= ~bits_to_reset;
+        s->odr |= bits_to_set;
+        update_gpio_idr(s);
+        return;
+    }
+    case GPIO_LCKR:
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: Locking port bits configuration isn't supported\n",
+                      __func__);
+        s->lckr = value & ~RESERVED_BITS_MASK;
+        return;
+    case GPIO_AFRL:
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: Alternate functions aren't supported\n",
+                      __func__);
+        s->afrl = value;
+        return;
+    case GPIO_AFRH:
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: Alternate functions aren't supported\n",
+                      __func__);
+        s->afrh = value;
+        return;
+    case GPIO_BRR: {
+        uint32_t bits_to_reset = value & ~RESERVED_BITS_MASK;
+        s->odr &= ~bits_to_reset;
+        update_gpio_idr(s);
+        return;
+    }
+    case GPIO_ASCR:
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: ADC function isn't supported\n",
+                      __func__);
+        s->ascr = value & ~RESERVED_BITS_MASK;
+        return;
+    /* a tweak to enable the qtest checking disconnected pins */
+    case GPIO_DISCONNECTED_PINS:
+        disconnect_gpio_pins(s, value);
+        return;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Bad offset 0x%" HWADDR_PRIx "\n", __func__, addr);
+    }
+}
+
+static uint64_t stm32l4x5_gpio_read(void *opaque, hwaddr addr,
+                                    unsigned int size)
+{
+    Stm32l4x5GpioState *s = opaque;
+
+    trace_stm32l4x5_gpio_read(addr);
+
+    switch (addr) {
+    case GPIO_MODER:
+        return s->moder;
+    case GPIO_OTYPER:
+        return s->otyper;
+    case GPIO_OSPEEDR:
+        return s->ospeedr;
+    case GPIO_PUPDR:
+        return s->pupdr;
+    case GPIO_IDR:
+        return s->idr;
+    case GPIO_ODR:
+        return s->odr;
+    case GPIO_BSRR:
+        return 0;
+    case GPIO_LCKR:
+        return s->lckr;
+    case GPIO_AFRL:
+        return s->afrl;
+    case GPIO_AFRH:
+        return s->afrh;
+    case GPIO_BRR:
+        return 0;
+    case GPIO_ASCR:
+        return s->ascr;
+    /* a tweak to enable the qtest checking disconnected pins */
+    case GPIO_DISCONNECTED_PINS:
+        return s->disconnected_pins;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Bad offset 0x%" HWADDR_PRIx "\n", __func__, addr);
+        return 0;
+    }
+}
+
+static const MemoryRegionOps stm32l4x5_gpio_ops = {
+    .read = stm32l4x5_gpio_read,
+    .write = stm32l4x5_gpio_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .impl = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+        .unaligned = false,
+    },
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+        .unaligned = false,
+    },
+};
+
+static void stm32l4x5_gpio_init(Object *obj)
+{
+    Stm32l4x5GpioState *s = STM32L4X5_GPIO(obj);
+
+    memory_region_init_io(&s->mmio, obj, &stm32l4x5_gpio_ops, s,
+                          TYPE_STM32L4X5_GPIO, 0x400);
+
+    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
+
+    qdev_init_gpio_out(DEVICE(obj), s->pin, GPIO_NUM_PINS);
+    qdev_init_gpio_in(DEVICE(obj), stm32l4x5_gpio_set, GPIO_NUM_PINS);
+
+    s->clk = qdev_init_clock_in(DEVICE(s), "clk", NULL, s, 0);
+}
+
+static void stm32l4x5_gpio_realize(DeviceState *dev, Error **errp)
+{
+    Stm32l4x5GpioState *s = STM32L4X5_GPIO(dev);
+    if (!clock_has_source(s->clk)) {
+        error_setg(errp, "GPIO: clk input must be connected");
+        return;
+    }
+}
+
+static const VMStateDescription vmstate_stm32l4x5_gpio = {
+    .name = TYPE_STM32L4X5_GPIO,
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]){
+        VMSTATE_UINT32(moder, Stm32l4x5GpioState),
+        VMSTATE_UINT32(otyper, Stm32l4x5GpioState),
+        VMSTATE_UINT32(ospeedr, Stm32l4x5GpioState),
+        VMSTATE_UINT32(pupdr, Stm32l4x5GpioState),
+        VMSTATE_UINT32(idr, Stm32l4x5GpioState),
+        VMSTATE_UINT32(odr, Stm32l4x5GpioState),
+        VMSTATE_UINT32(lckr, Stm32l4x5GpioState),
+        VMSTATE_UINT32(afrl, Stm32l4x5GpioState),
+        VMSTATE_UINT32(afrh, Stm32l4x5GpioState),
+        VMSTATE_UINT32(ascr, Stm32l4x5GpioState),
+        VMSTATE_UINT16(disconnected_pins, Stm32l4x5GpioState),
+        VMSTATE_UINT16(pins_connected_high, Stm32l4x5GpioState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void stm32l4x5_gpio_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    ResettableClass *rc = RESETTABLE_CLASS(klass);
+
+    dc->vmsd = &vmstate_stm32l4x5_gpio;
+    dc->realize = stm32l4x5_gpio_realize;
+    rc->phases.hold = stm32l4x5_gpio_reset_hold;
+}
+
+static void stm32l4x5_gpio_a_class_init(ObjectClass *klass, void *data)
+{
+    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
+
+    sc->moder_reset = 0xABFFFFFF;
+    sc->ospeedr_reset = 0x0C000000;
+    sc->pupdr_reset = 0x64000000;
+}
+
+static void stm32l4x5_gpio_b_class_init(ObjectClass *klass, void *data)
+{
+    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
+
+    sc->moder_reset = 0xFFFFFEBF;
+    sc->ospeedr_reset = 0x00000000;
+    sc->pupdr_reset = 0x00000100;
+}
+
+static void stm32l4x5_gpio_c_class_init(ObjectClass *klass, void *data)
+{
+    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
+
+    sc->moder_reset = 0xFFFFFFFF;
+    sc->ospeedr_reset = 0x00000000;
+    sc->pupdr_reset = 0x00000000;
+}
+
+static void stm32l4x5_gpio_d_class_init(ObjectClass *klass, void *data)
+{
+    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
+
+    sc->moder_reset = 0xFFFFFFFF;
+    sc->ospeedr_reset = 0x00000000;
+    sc->pupdr_reset = 0x00000000;
+}
+
+static void stm32l4x5_gpio_e_class_init(ObjectClass *klass, void *data)
+{
+    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
+
+    sc->moder_reset = 0xFFFFFFFF;
+    sc->ospeedr_reset = 0x00000000;
+    sc->pupdr_reset = 0x00000000;
+}
+
+static void stm32l4x5_gpio_f_class_init(ObjectClass *klass, void *data)
+{
+    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
+
+    sc->moder_reset = 0xFFFFFFFF;
+    sc->ospeedr_reset = 0x00000000;
+    sc->pupdr_reset = 0x00000000;
+}
+
+static void stm32l4x5_gpio_g_class_init(ObjectClass *klass, void *data)
+{
+    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
+
+    sc->moder_reset = 0xFFFFFFFF;
+    sc->ospeedr_reset = 0x00000000;
+    sc->pupdr_reset = 0x00000000;
+}
+
+static void stm32l4x5_gpio_h_class_init(ObjectClass *klass, void *data)
+{
+    Stm32l4x5GpioClass *sc = STM32L4X5_GPIO_CLASS(klass);
+
+    sc->moder_reset = 0x0000000F;
+    sc->ospeedr_reset = 0x00000000;
+    sc->pupdr_reset = 0x00000000;
+}
+
+static const TypeInfo stm32l4x5_gpio_types[] = {
+    {
+        .name = TYPE_STM32L4X5_GPIO,
+        .parent = TYPE_SYS_BUS_DEVICE,
+        .instance_size = sizeof(Stm32l4x5GpioState),
+        .instance_init = stm32l4x5_gpio_init,
+        .class_size     = sizeof(Stm32l4x5GpioClass),
+        .class_init = stm32l4x5_gpio_class_init,
+        .abstract = true,
+    }, {
+        .name = TYPE_STM32L4X5_GPIO_A,
+        .parent = TYPE_STM32L4X5_GPIO,
+        .class_init = stm32l4x5_gpio_a_class_init,
+    }, {
+        .name = TYPE_STM32L4X5_GPIO_B,
+        .parent = TYPE_STM32L4X5_GPIO,
+        .class_init = stm32l4x5_gpio_b_class_init,
+    }, {
+        .name = TYPE_STM32L4X5_GPIO_C,
+        .parent = TYPE_STM32L4X5_GPIO,
+        .class_init = stm32l4x5_gpio_c_class_init,
+    }, {
+        .name = TYPE_STM32L4X5_GPIO_D,
+        .parent = TYPE_STM32L4X5_GPIO,
+        .class_init = stm32l4x5_gpio_d_class_init,
+    }, {
+        .name = TYPE_STM32L4X5_GPIO_E,
+        .parent = TYPE_STM32L4X5_GPIO,
+        .class_init = stm32l4x5_gpio_e_class_init,
+    }, {
+        .name = TYPE_STM32L4X5_GPIO_F,
+        .parent = TYPE_STM32L4X5_GPIO,
+        .class_init = stm32l4x5_gpio_f_class_init,
+    }, {
+        .name = TYPE_STM32L4X5_GPIO_G,
+        .parent = TYPE_STM32L4X5_GPIO,
+        .class_init = stm32l4x5_gpio_g_class_init,
+    }, {
+        .name = TYPE_STM32L4X5_GPIO_H,
+        .parent = TYPE_STM32L4X5_GPIO,
+        .class_init = stm32l4x5_gpio_h_class_init,
+    },
+};
+
+DEFINE_TYPES(stm32l4x5_gpio_types)
diff --git a/hw/gpio/trace-events b/hw/gpio/trace-events
index 9736b362ac..8cbf75a897 100644
--- a/hw/gpio/trace-events
+++ b/hw/gpio/trace-events
@@ -31,3 +31,9 @@  sifive_gpio_update_output_irq(int64_t line, int64_t value) "line %" PRIi64 " val
 # aspeed_gpio.c
 aspeed_gpio_read(uint64_t offset, uint64_t value) "offset: 0x%" PRIx64 " value 0x%" PRIx64
 aspeed_gpio_write(uint64_t offset, uint64_t value) "offset: 0x%" PRIx64 " value 0x%" PRIx64
+
+# stm32l4x5_gpio.c
+stm32l4x5_gpio_read(uint64_t addr) "reg read: addr: 0x%" PRIx64 " "
+stm32l4x5_gpio_write(uint64_t addr, uint64_t data) "reg write: addr: 0x%" PRIx64 " val: 0x%" PRIx64 ""
+stm32l4x5_gpio_update_idr(uint32_t old_idr, uint32_t new_idr) "previous idr: 0x%x new idr: 0x%x"
+stm32l4x5_gpio_pins(uint16_t disconnected, uint16_t high) "disconnected pins: 0x%x levels: 0x%x"
diff --git a/include/hw/gpio/stm32l4x5_gpio.h b/include/hw/gpio/stm32l4x5_gpio.h
new file mode 100644
index 0000000000..40aae52ffb
--- /dev/null
+++ b/include/hw/gpio/stm32l4x5_gpio.h
@@ -0,0 +1,80 @@ 
+/*
+ * STM32L4x5 GPIO (General Purpose Input/Ouput)
+ *
+ * Copyright (c) 2023 Arnaud Minier <arnaud.minier@telecom-paris.fr>
+ * Copyright (c) 2023 Inès Varhol <ines.varhol@telecom-paris.fr>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+/*
+ * The reference used is the STMicroElectronics RM0351 Reference manual
+ * for STM32L4x5 and STM32L4x6 advanced Arm ® -based 32-bit MCUs.
+ * https://www.st.com/en/microcontrollers-microprocessors/stm32l4x5/documentation.html
+ */
+
+#ifndef HW_STM32L4X5_GPIO_H
+#define HW_STM32L4X5_GPIO_H
+
+#include "hw/sysbus.h"
+#include "qom/object.h"
+
+#define TYPE_STM32L4X5_GPIO "stm32l4x5-gpio"
+#define TYPE_STM32L4X5_GPIO_A "stm32l4x5-gpio-a"
+#define TYPE_STM32L4X5_GPIO_B "stm32l4x5-gpio-b"
+#define TYPE_STM32L4X5_GPIO_C "stm32l4x5-gpio-c"
+#define TYPE_STM32L4X5_GPIO_D "stm32l4x5-gpio-d"
+#define TYPE_STM32L4X5_GPIO_E "stm32l4x5-gpio-e"
+#define TYPE_STM32L4X5_GPIO_F "stm32l4x5-gpio-f"
+#define TYPE_STM32L4X5_GPIO_G "stm32l4x5-gpio-g"
+#define TYPE_STM32L4X5_GPIO_H "stm32l4x5-gpio-h"
+OBJECT_DECLARE_TYPE(Stm32l4x5GpioState, Stm32l4x5GpioClass, STM32L4X5_GPIO)
+
+#define GPIO_NUM_PINS 16
+
+struct Stm32l4x5GpioState {
+    SysBusDevice parent_obj;
+
+    MemoryRegion mmio;
+
+    /* GPIO registers */
+    uint32_t moder;
+    uint32_t otyper;
+    uint32_t ospeedr;
+    uint32_t pupdr;
+    uint32_t idr;
+    uint32_t odr;
+    uint32_t lckr;
+    uint32_t afrl;
+    uint32_t afrh;
+    uint32_t ascr;
+
+    /*
+     * External driving of pins.
+     * The pins can be set externally through the device
+     * anonymous input GPIOs lines under certain conditions.
+     * The pin must not be in push-pull output mode,
+     * and can't be set high in open-drain mode.
+     * Pins driven externally and configured to
+     * output mode will in general be "disconnected"
+     * (see `get_gpio_pins_to_disconnect()`)
+     */
+    uint16_t disconnected_pins;
+    uint16_t pins_connected_high;
+
+    Clock *clk;
+    qemu_irq pin[GPIO_NUM_PINS];
+};
+
+struct Stm32l4x5GpioClass {
+    SysBusDeviceClass parent_class;
+
+    uint32_t moder_reset;
+    uint32_t ospeedr_reset;
+    uint32_t pupdr_reset;
+};
+
+#endif