From a78e9839ae5eb0b95d9db8dd672e2977d2831605 Mon Sep 17 00:00:00 2001 From: Klaus Jensen Date: Thu, 30 Jun 2022 09:21:14 +0200 Subject: hw/i2c: add asynchronous send MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add an asynchronous version of i2c_send() that requires the slave to explicitly acknowledge on the bus with i2c_ack(). The current master must use the new i2c_start_send_async() to indicate that it wants to do an asynchronous transfer. This allows the i2c core to check if the target slave supports this or not. This approach relies on adding a new enum i2c_event member, which is why a bunch of other devices needs changes in their event handling switches. Signed-off-by: Klaus Jensen Message-Id: <20220601210831.67259-5-its@irrelevant.dk> Signed-off-by: Cédric Le Goater Message-Id: <20220630045133.32251-6-me@pjd.dev> Signed-off-by: Cédric Le Goater --- include/hw/i2c/i2c.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include/hw/i2c') diff --git a/include/hw/i2c/i2c.h b/include/hw/i2c/i2c.h index be8bb8b..9b9581d 100644 --- a/include/hw/i2c/i2c.h +++ b/include/hw/i2c/i2c.h @@ -12,6 +12,7 @@ enum i2c_event { I2C_START_RECV, I2C_START_SEND, + I2C_START_SEND_ASYNC, I2C_FINISH, I2C_NACK /* Masker NACKed a receive byte. */ }; @@ -28,6 +29,9 @@ struct I2CSlaveClass { /* Master to slave. Returns non-zero for a NAK, 0 for success. */ int (*send)(I2CSlave *s, uint8_t data); + /* Master to slave (asynchronous). Receiving slave must call i2c_ack(). */ + void (*send_async)(I2CSlave *s, uint8_t data); + /* * Slave to master. This cannot fail, the device should always * return something here. @@ -127,11 +131,23 @@ int i2c_start_recv(I2CBus *bus, uint8_t address); */ int i2c_start_send(I2CBus *bus, uint8_t address); +/** + * i2c_start_send_async: start an asynchronous 'send' transfer on an I2C bus. + * + * @bus: #I2CBus to be used + * @address: address of the slave + * + * Return: 0 on success, -1 on error + */ +int i2c_start_send_async(I2CBus *bus, uint8_t address); + void i2c_end_transfer(I2CBus *bus); void i2c_nack(I2CBus *bus); +void i2c_ack(I2CBus *bus); void i2c_bus_master(I2CBus *bus, QEMUBH *bh); void i2c_bus_release(I2CBus *bus); int i2c_send(I2CBus *bus, uint8_t data); +int i2c_send_async(I2CBus *bus, uint8_t data); uint8_t i2c_recv(I2CBus *bus); bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast, I2CNodeList *current_devs); -- cgit v1.1