Most I2C controllers do not have a dedicated pin for SMBus Alerts. Allow them to define a GPIO as a side-channel. Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> --- The binding addition for dt-schema is here: https://lore.kernel.org/r/20240909105835.28531-1-wsa+renesas@xxxxxxxxxxxxxxxxxxxx Tested with a Renesas Lager board (R-Car H2). drivers/i2c/i2c-core-smbus.c | 9 ++++++--- drivers/i2c/i2c-smbus.c | 22 ++++++++++++++++------ 2 files changed, 22 insertions(+), 9 deletions(-) diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c index 967bd712c638..fb3d4674be0c 100644 --- a/drivers/i2c/i2c-core-smbus.c +++ b/drivers/i2c/i2c-core-smbus.c @@ -712,12 +712,15 @@ int i2c_setup_smbus_alert(struct i2c_adapter *adapter) if (!parent || i2c_verify_adapter(parent)) return 0; + /* Report serious errors */ irq = device_property_match_string(parent, "interrupt-names", "smbus_alert"); - if (irq == -EINVAL || irq == -ENODATA) - return 0; - else if (irq < 0) + if (irq < 0 && irq != -EINVAL && irq != -ENODATA) return irq; + /* Skip setup when no irq was found */ + if (irq < 0 && !device_property_present(parent, "smbalert-gpios")) + return 0; + return PTR_ERR_OR_ZERO(i2c_new_smbus_alert_device(adapter, NULL)); } #endif diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c index bf23e3446123..10198e5efb50 100644 --- a/drivers/i2c/i2c-smbus.c +++ b/drivers/i2c/i2c-smbus.c @@ -9,6 +9,7 @@ #define DEBUG #include <linux/device.h> #include <linux/dmi.h> +#include <linux/gpio/consumer.h> #include <linux/i2c.h> #include <linux/i2c-smbus.h> #include <linux/interrupt.h> @@ -168,6 +169,8 @@ static int smbalert_probe(struct i2c_client *ara) struct i2c_smbus_alert_setup *setup = dev_get_platdata(&ara->dev); struct i2c_smbus_alert *alert; struct i2c_adapter *adapter = ara->adapter; + unsigned long irqflags = IRQF_SHARED | IRQF_ONESHOT; + struct gpio_desc *gpiod; int res, irq; alert = devm_kzalloc(&ara->dev, sizeof(struct i2c_smbus_alert), @@ -180,18 +183,25 @@ static int smbalert_probe(struct i2c_client *ara) } else { irq = fwnode_irq_get_byname(dev_fwnode(adapter->dev.parent), "smbus_alert"); - if (irq <= 0) - return irq; + if (irq <= 0) { + gpiod = devm_gpiod_get(adapter->dev.parent, "smbalert", GPIOD_IN); + if (IS_ERR(gpiod)) + return PTR_ERR(gpiod); + + irq = gpiod_to_irq(gpiod); + if (irq <= 0) + return irq; + + irqflags |= IRQF_TRIGGER_FALLING; + } } INIT_WORK(&alert->alert, smbalert_work); alert->ara = ara; if (irq > 0) { - res = devm_request_threaded_irq(&ara->dev, irq, - NULL, smbus_alert, - IRQF_SHARED | IRQF_ONESHOT, - "smbus_alert", alert); + res = devm_request_threaded_irq(&ara->dev, irq, NULL, smbus_alert, + irqflags, "smbus_alert", alert); if (res) return res; } -- 2.43.0
