Commit 96cdf2fd authored Feb 23, 2022 by Lucas Denefle Committed by Greg Kroah-Hartman Apr 15, 2022

w1: w1_therm: fixes w1_seq for ds28ea00 sensors



[ Upstream commit 41a92a89eee819298f805c40187ad8b02bb53426 ]

w1_seq was failing due to several devices responding to the
CHAIN_DONE at the same time. Now properly selects the current
device in the chain with MATCH_ROM. Also acknowledgment was
read twice.

Signed-off-by: Lucas Denefle <lucas.denefle@converge.io>
Link: https://lore.kernel.org/r/20220223113558.232750-1-lucas.denefle@converge.io


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 823f0364

drivers/w1/slaves/w1_therm.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -679,16 +679,20 @@ static ssize_t w1_seq_show(struct device *device,
		if (sl->reg_num.id == reg_num->id)
		seq = i;

		if (w1_reset_bus(sl->master))
		goto error;

		/* Put the device into chain DONE state */
		w1_write_8(sl->master, W1_MATCH_ROM);
		w1_write_block(sl->master, (u8 *)&rn, 8);
		w1_write_8(sl->master, W1_42_CHAIN);
		w1_write_8(sl->master, W1_42_CHAIN_DONE);
		w1_write_8(sl->master, W1_42_CHAIN_DONE_INV);
		w1_read_block(sl->master, &ack, sizeof(ack));

		/* check for acknowledgment */
		ack = w1_read_8(sl->master);
		if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
		goto error;

		}

		/* Exit from CHAIN state */