Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit c7b0a7c1 authored by Sifan Naeem's avatar Sifan Naeem Committed by Wolfram Sang
Browse files

i2c: img-scb: add handle for Master halt interrupt 



Master halt is issued after each byte of a transaction is processed in
IP version 3.3.
Master halt will stall the bus by holding the SCK line low until the
halt bit in the scb_general_control is cleared.

After the last byte of a transfer is processed we can use the Master
Halt interrupt to facilitate a repeated start transfer without
issuing a stop bit.

Signed-off-by: default avatarSifan Naeem <sifan.naeem@imgtec.com>
Reviewed-by: default avatarJames Hartley <james.hartley@imgtec.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent dd29207e

drivers/i2c/busses/i2c-img-scb.c

+14 −3
Original line number Diff line number Diff line
@@ -151,6 +151,7 @@ 
#define INT_FIFO_EMPTYING		BIT(12)

#define INT_TRANSACTION_DONE		BIT(15)

#define INT_SLAVE_EVENT			BIT(16)

#define INT_MASTER_HALTED		BIT(17)

#define INT_TIMING			BIT(18)

#define INT_STOP_DETECTED		BIT(19)
@@ -177,6 +178,7 @@ 
					 INT_FIFO_FULL        | \

					 INT_FIFO_FILLING     | \

					 INT_FIFO_EMPTY       | \

					 INT_MASTER_HALTED    | \

					 INT_STOP_DETECTED)



#define INT_ENABLE_MASK_WAITSTOP	(INT_SLAVE_EVENT      | \
@@ -875,18 +877,27 @@ static unsigned int img_i2c_auto(struct img_i2c *i2c, 
	}



	if (i2c->msg.flags & I2C_M_RD) {

		if (int_status & INT_FIFO_FULL_FILLING) {

		if (int_status & (INT_FIFO_FULL_FILLING | INT_MASTER_HALTED)) {

			img_i2c_read_fifo(i2c);

			if (i2c->msg.len == 0)

				return ISR_WAITSTOP;

		}

	} else {

		if (int_status & INT_FIFO_EMPTY) {

			if (i2c->msg.len == 0)

		if (int_status & (INT_FIFO_EMPTY | INT_MASTER_HALTED)) {

			if ((int_status & INT_FIFO_EMPTY) &&

			    i2c->msg.len == 0)

				return ISR_WAITSTOP;

			img_i2c_write_fifo(i2c);

		}

	}

	if (int_status & INT_MASTER_HALTED) {

		/*

		 * Release and then enable transaction halt, to

		 * allow only a single byte to proceed.

		 */

		img_i2c_transaction_halt(i2c, false);

		img_i2c_transaction_halt(i2c, !i2c->last_msg);

	}



	return 0;

}