linux-kernel - [PATCH v2 07/10] media: tda1004x: switch to i2c_lock_bus(..., I2C_LOCK

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Date:   Wed, 20 Jun 2018 07:18:00 +0200
From:   Peter Rosin <peda@...ntia.se>
To:     linux-kernel@...r.kernel.org
Cc:     Peter Rosin <peda@...ntia.se>, Peter Huewe <peterhuewe@....de>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Jason Gunthorpe <jgg@...pe.ca>, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Brian Norris <computersforpeace@...il.com>,
        Gregory Fong <gregory.0xf0@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        bcm-kernel-feedback-list@...adcom.com,
        Sekhar Nori <nsekhar@...com>,
        Kevin Hilman <khilman@...nel.org>,
        Haavard Skinnemoen <hskinnemoen@...il.com>,
        Kukjin Kim <kgene@...nel.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Orson Zhai <orsonzhai@...il.com>,
        Baolin Wang <baolin.wang@...aro.org>,
        Chunyan Zhang <zhang.lyra@...il.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Guenter Roeck <linux@...ck-us.net>, Crt Mori <cmo@...exis.com>,
        Jonathan Cameron <jic23@...nel.org>,
        Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Antti Palosaari <crope@....fi>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Michael Krufky <mkrufky@...uxtv.org>,
        Lee Jones <lee.jones@...aro.org>,
        linux-integrity@...r.kernel.org, linux-i2c@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-iio@...r.kernel.org,
        linux-input@...r.kernel.org, linux-media@...r.kernel.org
Subject: [PATCH v2 07/10] media: tda1004x: switch to i2c_lock_bus(..., I2C_LOCK_SEGMENT)

Locking the root adapter for __i2c_transfer will deadlock if the
device sits behind a mux-locked I2C mux. Switch to the finer-grained
i2c_lock_bus with the I2C_LOCK_SEGMENT flag. If the device does not
sit behind a mux-locked mux, the two locking variants are equivalent.

Signed-off-by: Peter Rosin <peda@...ntia.se>
---
 drivers/media/dvb-frontends/tda1004x.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/media/dvb-frontends/tda1004x.c b/drivers/media/dvb-frontends/tda1004x.c
index 7dcfb4a4b2d0..9d3261bf5090 100644
--- a/drivers/media/dvb-frontends/tda1004x.c
+++ b/drivers/media/dvb-frontends/tda1004x.c
@@ -329,7 +329,7 @@ static int tda1004x_do_upload(struct tda1004x_state *state,
 	tda1004x_write_byteI(state, dspCodeCounterReg, 0);
 	fw_msg.addr = state->config->demod_address;
 
-	i2c_lock_adapter(state->i2c);
+	i2c_lock_bus(state->i2c, I2C_LOCK_SEGMENT);
 	buf[0] = dspCodeInReg;
 	while (pos != len) {
 		// work out how much to send this time
@@ -342,14 +342,14 @@ static int tda1004x_do_upload(struct tda1004x_state *state,
 		fw_msg.len = tx_size + 1;
 		if (__i2c_transfer(state->i2c, &fw_msg, 1) != 1) {
 			printk(KERN_ERR "tda1004x: Error during firmware upload\n");
-			i2c_unlock_adapter(state->i2c);
+			i2c_unlock_bus(state->i2c, I2C_LOCK_SEGMENT);
 			return -EIO;
 		}
 		pos += tx_size;
 
 		dprintk("%s: fw_pos=0x%x\n", __func__, pos);
 	}
-	i2c_unlock_adapter(state->i2c);
+	i2c_unlock_bus(state->i2c, I2C_LOCK_SEGMENT);
 
 	/* give the DSP a chance to settle 03/10/05 Hac */
 	msleep(100);
-- 
2.11.0