@@ -785,6 +785,25 @@ static int aspeed_i2c_unreg_slave(struct i2c_client *client)
return 0;
}
+
+static int aspeed_i2c_slave_enable(struct i2c_client *client, bool enable)
+{
+ struct aspeed_i2c_bus *bus = i2c_get_adapdata(client->adapter);
+ u32 func_ctrl_reg_val;
+
+ if (!bus->slave)
+ return -EINVAL;
+
+ /* Toggle slave mode. */
+ func_ctrl_reg_val = readl(bus->base + ASPEED_I2C_FUN_CTRL_REG);
+ if (enable)
+ func_ctrl_reg_val |= ASPEED_I2CD_SLAVE_EN;
+ else
+ func_ctrl_reg_val &= ~ASPEED_I2CD_SLAVE_EN;
+ writel(func_ctrl_reg_val, bus->base + ASPEED_I2C_FUN_CTRL_REG);
+
+ return 0;
+}
#endif /* CONFIG_I2C_SLAVE */
static const struct i2c_algorithm aspeed_i2c_algo = {
@@ -793,6 +812,7 @@ static const struct i2c_algorithm aspeed_i2c_algo = {
#if IS_ENABLED(CONFIG_I2C_SLAVE)
.reg_slave = aspeed_i2c_reg_slave,
.unreg_slave = aspeed_i2c_unreg_slave,
+ .slave_enable = aspeed_i2c_slave_enable,
#endif /* CONFIG_I2C_SLAVE */
};
@@ -520,6 +520,7 @@ i2c_register_board_info(int busnum, struct i2c_board_info const *info,
* from the ``I2C_FUNC_*`` flags.
* @reg_slave: Register given client to I2C slave mode of this adapter
* @unreg_slave: Unregister given client from I2C slave mode of this adapter
+ * @slave_enable: Toggle enable slave mode for given client of this adapter
*
* The following structs are for those who like to implement new bus drivers:
* i2c_algorithm is the interface to a class of hardware solutions which can
@@ -557,6 +558,7 @@ struct i2c_algorithm {
#if IS_ENABLED(CONFIG_I2C_SLAVE)
int (*reg_slave)(struct i2c_client *client);
int (*unreg_slave)(struct i2c_client *client);
+ int (*slave_enable)(struct i2c_client *client, bool enable);
#endif
};
Slave needs time to prepare the response data before Master could enquiry via read transaction. However, there is no mechanism for i2c-aspeed Slave to notify Master that it needs more time to process and this make Master side to time out when trying to get the response. This commit introduces the slave_enable() callback in struct i2c_algorithm for Slave to temporary stop the Slave mode while working on the response and re-enable the Slave when response data ready. Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com> --- v4: + First introduced follow Ryan's suggestion [Ryan] + Fix recursive spinlock issue in v3 (aspeed_set_slave_busy()) and apply in this patch [Graeme] drivers/i2c/busses/i2c-aspeed.c | 20 ++++++++++++++++++++ include/linux/i2c.h | 2 ++ 2 files changed, 22 insertions(+)