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hw/i2c: add asynchronous send

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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 <k.jensen@samsung.com>
Message-Id: <20220601210831.67259-5-its@irrelevant.dk>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20220630045133.32251-6-me@pjd.dev>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
This commit is contained in:
Klaus Jensen 2022-06-30 09:21:14 +02:00 • committed by Cédric Le Goater
parent 37fa5ca426
commit a78e9839ae
9 changed files with 67 additions and 1 deletions
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16
include/hw/i2c/i2c.h
View file

@ -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);