linux-kernel - [PATCH AUTOSEL 4.19 005/106] media: si2157: Better check for running tuner in init

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Message-Id: <20200608232238.3368589-5-sashal@kernel.org>
Date:   Mon,  8 Jun 2020 19:20:57 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Brad Love <brad@...tdimension.cc>, Sean Young <sean@...s.org>,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        Sasha Levin <sashal@...nel.org>, linux-media@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 005/106] media: si2157: Better check for running tuner in init

From: Brad Love <brad@...tdimension.cc>

[ Upstream commit e955f959ac52e145f27ff2be9078b646d0352af0 ]

Getting the Xtal trim property to check if running is less error prone.
Reset if_frequency if state is unknown.

Replaces the previous "garbage check".

Signed-off-by: Brad Love <brad@...tdimension.cc>
Signed-off-by: Sean Young <sean@...s.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/media/tuners/si2157.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/media/tuners/si2157.c b/drivers/media/tuners/si2157.c
index a08d8fe2bb1b..13770b038048 100644
--- a/drivers/media/tuners/si2157.c
+++ b/drivers/media/tuners/si2157.c
@@ -84,24 +84,23 @@ static int si2157_init(struct dvb_frontend *fe)
 	struct si2157_cmd cmd;
 	const struct firmware *fw;
 	const char *fw_name;
-	unsigned int uitmp, chip_id;
+	unsigned int chip_id, xtal_trim;
 
 	dev_dbg(&client->dev, "\n");
 
-	/* Returned IF frequency is garbage when firmware is not running */
-	memcpy(cmd.args, "\x15\x00\x06\x07", 4);
+	/* Try to get Xtal trim property, to verify tuner still running */
+	memcpy(cmd.args, "\x15\x00\x04\x02", 4);
 	cmd.wlen = 4;
 	cmd.rlen = 4;
 	ret = si2157_cmd_execute(client, &cmd);
-	if (ret)
-		goto err;
 
-	uitmp = cmd.args[2] << 0 | cmd.args[3] << 8;
-	dev_dbg(&client->dev, "if_frequency kHz=%u\n", uitmp);
+	xtal_trim = cmd.args[2] | (cmd.args[3] << 8);
 
-	if (uitmp == dev->if_frequency / 1000)
+	if (ret == 0 && xtal_trim < 16)
 		goto warm;
 
+	dev->if_frequency = 0; /* we no longer know current tuner state */
+
 	/* power up */
 	if (dev->chiptype == SI2157_CHIPTYPE_SI2146) {
 		memcpy(cmd.args, "\xc0\x05\x01\x00\x00\x0b\x00\x00\x01", 9);
-- 
2.25.1