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hw/gpio/pca9552: add pca9535 support

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Extend the 16-bit PCA9552 model to support non-LED devices such as
the PCA9535[1].

[1]: https://www.ti.com/lit/ds/symlink/pca9535.pdf

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Reviewed-by: Glenn Miles <milesg@linux.ibm.com>
Link: https://lore.kernel.org/qemu-devel/20260121-pca9535-v1-1-164640e622ff@stwcx.xyz
Signed-off-by: Cédric Le Goater <clg@redhat.com>
This commit is contained in:
Patrick Williams
2026-01-21 13:17:05 -05:00
committed by Cédric Le Goater
parent 0a1d477067
commit f139033e58
3 changed files with 134 additions and 55 deletions
Download Patch File Download Diff File Expand all files Collapse all files

178
hw/gpio/pca9552.c
View File

@@ -31,6 +31,7 @@ struct PCA955xClass {
uint8_t pin_count;
uint8_t max_reg;
bool has_led_support;
};
typedef struct PCA955xClass PCA955xClass;
@@ -113,32 +114,59 @@ static void pca955x_update_pin_input(PCA955xState *s)
for (i = 0; i < k->pin_count; i++) {
uint8_t input_reg = PCA9552_INPUT0 + (i / 8);
uint8_t bit_mask = 1 << (i % 8);
uint8_t config = pca955x_pin_get_config(s, i);
uint8_t old_value = s->regs[input_reg] & bit_mask;
uint8_t new_value;
switch (config) {
case PCA9552_LED_ON:
/* Pin is set to 0V to turn on LED */
s->regs[input_reg] &= ~bit_mask;
break;
case PCA9552_LED_OFF:
/*
* Pin is set to Hi-Z to turn off LED and
* pullup sets it to a logical 1 unless
* external device drives it low.
*/
if (s->ext_state[i] == PCA9552_PIN_LOW) {
if (k->has_led_support) {
/* PCA9552: LED control behavior */
uint8_t config = pca955x_pin_get_config(s, i);
switch (config) {
case PCA9552_LED_ON:
/* Pin is set to 0V to turn on LED */
s->regs[input_reg] &= ~bit_mask;
} else {
s->regs[input_reg] |= bit_mask;
break;
case PCA9552_LED_OFF:
/*
* Pin is set to Hi-Z to turn off LED and
* pullup sets it to a logical 1 unless
* external device drives it low.
*/
if (s->ext_state[i] == PCA9552_PIN_LOW) {
s->regs[input_reg] &= ~bit_mask;
} else {
s->regs[input_reg] |= bit_mask;
}
break;
case PCA9552_LED_PWM0:
case PCA9552_LED_PWM1:
/* TODO */
default:
break;
}
} else {
/* PCA9535: Simple GPIO behavior */
uint8_t config_reg = PCA9535_CONFIG0 + (i / 8);
uint8_t output_reg = PCA9535_OUTPUT0 + (i / 8);
uint8_t polarity_reg = PCA9535_POLARITY0 + (i / 8);
/* Check if pin is configured as input */
if (s->regs[config_reg] & bit_mask) {
/* Input mode - reflect external state */
if (s->ext_state[i] == PCA9552_PIN_LOW) {
s->regs[input_reg] &= ~bit_mask;
} else {
s->regs[input_reg] |= bit_mask;
}
} else {
/* Output mode - reflect output register value */
uint8_t output_bit = s->regs[output_reg] & bit_mask;
uint8_t polarity_bit = s->regs[polarity_reg] & bit_mask;
/* Apply polarity inversion if set */
s->regs[input_reg] = (s->regs[input_reg] & ~bit_mask) |
((output_bit ^ polarity_bit) & bit_mask);
}
break;
case PCA9552_LED_PWM0:
case PCA9552_LED_PWM1:
/* TODO */
default:
break;
}
/* update irq state only if pin state changed */
@@ -151,52 +179,52 @@ static void pca955x_update_pin_input(PCA955xState *s)
static uint8_t pca955x_read(PCA955xState *s, uint8_t reg)
{
switch (reg) {
case PCA9552_INPUT0:
case PCA9552_INPUT1:
case PCA9552_PSC0:
case PCA9552_PWM0:
case PCA9552_PSC1:
case PCA9552_PWM1:
case PCA9552_LS0:
case PCA9552_LS1:
case PCA9552_LS2:
case PCA9552_LS3:
return s->regs[reg];
default:
PCA955xClass *k = PCA955X_GET_CLASS(s);
if (reg > k->max_reg) {
qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected read to register %d\n",
__func__, reg);
return 0xFF;
}
return s->regs[reg];
}
static void pca955x_write(PCA955xState *s, uint8_t reg, uint8_t data)
{
PCA955xClass *k = PCA955X_GET_CLASS(s);
uint16_t pins_status;
switch (reg) {
case PCA9552_PSC0:
case PCA9552_PWM0:
case PCA9552_PSC1:
case PCA9552_PWM1:
s->regs[reg] = data;
break;
case PCA9552_LS0:
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:
case PCA9552_INPUT1:
default:
if (reg > k->max_reg) {
qemu_log_mask(LOG_GUEST_ERROR, "%s: unexpected write to register %d\n",
__func__, reg);
return;
}
/* Handle read-only registers */
if (reg == PCA9552_INPUT0 || reg == PCA9552_INPUT1) {
qemu_log_mask(LOG_GUEST_ERROR,
"%s: unexpected write to read-only register %d\n",
__func__, reg);
return;
}
pins_status = pca955x_pins_get_status(s);
s->regs[reg] = data;
/* Update GPIO state if this register affects outputs */
if (k->has_led_support) {
/* PCA9552: Update on LED selector register writes */
if (reg >= PCA9552_LS0 && reg <= PCA9552_LS3) {
pca955x_update_pin_input(s);
pca955x_display_pins_status(s, pins_status);
}
} else {
/* PCA9535: Update on OUTPUT, POLARITY, or CONFIG register writes */
if (reg >= PCA9535_OUTPUT0 && reg <= PCA9535_CONFIG1) {
pca955x_update_pin_input(s);
pca955x_display_pins_status(s, pins_status);
}
}
}
@@ -379,6 +407,26 @@ static void pca9552_reset(DeviceState *dev)
s->len = 0;
}
static void pca9535_reset(DeviceState *dev)
{
PCA955xState *s = PCA955X(dev);
s->regs[PCA9535_INPUT0] = 0xFF; /* All inputs high (pull-ups) */
s->regs[PCA9535_INPUT1] = 0xFF; /* All inputs high (pull-ups) */
s->regs[PCA9535_OUTPUT0] = 0xFF; /* All outputs high */
s->regs[PCA9535_OUTPUT1] = 0xFF; /* All outputs high */
s->regs[PCA9535_POLARITY0] = 0x00; /* No polarity inversion */
s->regs[PCA9535_POLARITY1] = 0x00; /* No polarity inversion */
s->regs[PCA9535_CONFIG0] = 0xFF; /* All pins as inputs */
s->regs[PCA9535_CONFIG1] = 0xFF; /* All pins as inputs */
memset(s->ext_state, PCA9552_PIN_HIZ, PCA955X_PIN_COUNT_MAX);
pca955x_update_pin_input(s);
s->pointer = 0xFF;
s->len = 0;
}
static void pca955x_initfn(Object *obj)
{
PCA955xClass *k = PCA955X_GET_CLASS(obj);
@@ -463,6 +511,19 @@ static void pca9552_class_init(ObjectClass *oc, const void *data)
dc->vmsd = &pca9552_vmstate;
pc->max_reg = PCA9552_LS3;
pc->pin_count = 16;
pc->has_led_support = true;
}
static void pca9535_class_init(ObjectClass *oc, const void *data)
{
DeviceClass *dc = DEVICE_CLASS(oc);
PCA955xClass *pc = PCA955X_CLASS(oc);
device_class_set_legacy_reset(dc, pca9535_reset);
dc->vmsd = &pca9552_vmstate;
pc->max_reg = PCA9535_CONFIG1;
pc->pin_count = 16;
pc->has_led_support = false;
}
static const TypeInfo pca9552_info = {
@@ -471,10 +532,17 @@ static const TypeInfo pca9552_info = {
.class_init = pca9552_class_init,
};
static const TypeInfo pca9535_info = {
.name = TYPE_PCA9535,
.parent = TYPE_PCA955X,
.class_init = pca9535_class_init,
};
static void pca955x_register_types(void)
{
type_register_static(&pca955x_info);
type_register_static(&pca9552_info);
type_register_static(&pca9535_info);
}
type_init(pca955x_register_types)

1
include/hw/gpio/pca9552.h
View File

@@ -14,6 +14,7 @@
#define TYPE_PCA9552 "pca9552"
#define TYPE_PCA955X "pca955x"
#define TYPE_PCA9535 "pca9535"
typedef struct PCA955xState PCA955xState;
DECLARE_INSTANCE_CHECKER(PCA955xState, PCA955X,
TYPE_PCA955X)

10
include/hw/gpio/pca9552_regs.h
View File

@@ -29,4 +29,14 @@
*/
#define PCA9552_AUTOINC (1 << 4)
/* PCA9535 Registers (same addresses, different semantics) */
#define PCA9535_INPUT0 0 /* read only input register 0 */
#define PCA9535_INPUT1 1 /* read only input register 1 */
#define PCA9535_OUTPUT0 2 /* read/write output register 0 */
#define PCA9535_OUTPUT1 3 /* read/write output register 1 */
#define PCA9535_POLARITY0 4 /* read/write polarity inversion register 0 */
#define PCA9535_POLARITY1 5 /* read/write polarity inversion register 1 */
#define PCA9535_CONFIG0 6 /* read/write configuration register 0 */
#define PCA9535_CONFIG1 7 /* read/write configuration register 1 */
#endif