diff mbox

[02/11] tpm/tpm_i2c_infineon: switch to i2c_lock_segment

Message ID 20180615101506.8012-3-peda@axentia.se (mailing list archive)
State New, archived
Headers show

Commit Message

Peter Rosin June 15, 2018, 10:14 a.m. UTC
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_segment. If the device does not sit behind a mux-locked mux,
the two locking variants are equivalent.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/char/tpm/tpm_i2c_infineon.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Jarkko Sakkinen June 19, 2018, 12:56 p.m. UTC | #1
On Fri, Jun 15, 2018 at 12:14:57PM +0200, Peter Rosin wrote:
> 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_segment. If the device does not sit behind a mux-locked mux,
> the two locking variants are equivalent.
> 
> Signed-off-by: Peter Rosin <peda@axentia.se>

Can you quickly explain (or give a reference) the difference with these
functions? Not an expert in this area. Thanks.

/Jarkko
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Peter Rosin June 19, 2018, 1:05 p.m. UTC | #2
On 2018-06-19 14:56, Jarkko Sakkinen wrote:
> On Fri, Jun 15, 2018 at 12:14:57PM +0200, Peter Rosin wrote:
>> 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_segment. If the device does not sit behind a mux-locked mux,
>> the two locking variants are equivalent.
>>
>> Signed-off-by: Peter Rosin <peda@axentia.se>
> 
> Can you quickly explain (or give a reference) the difference with these
> functions? Not an expert in this area. Thanks.

There are some words in the cover letter. If you need more, there's
always Documentation/i2c/i2c-topology. Hope that helps, otherwise I'll
try to explain better...

Cheers,
Peter
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diff mbox

Patch

diff --git a/drivers/char/tpm/tpm_i2c_infineon.c b/drivers/char/tpm/tpm_i2c_infineon.c
index 6116cd05e228..b2889405b4fa 100644
--- a/drivers/char/tpm/tpm_i2c_infineon.c
+++ b/drivers/char/tpm/tpm_i2c_infineon.c
@@ -117,7 +117,7 @@  static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
 	/* Lock the adapter for the duration of the whole sequence. */
 	if (!tpm_dev.client->adapter->algo->master_xfer)
 		return -EOPNOTSUPP;
-	i2c_lock_adapter(tpm_dev.client->adapter);
+	i2c_lock_segment(tpm_dev.client->adapter);
 
 	if (tpm_dev.chip_type == SLB9645) {
 		/* use a combined read for newer chips
@@ -192,7 +192,7 @@  static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
 	}
 
 out:
-	i2c_unlock_adapter(tpm_dev.client->adapter);
+	i2c_unlock_segment(tpm_dev.client->adapter);
 	/* take care of 'guard time' */
 	usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 
@@ -224,7 +224,7 @@  static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
 
 	if (!tpm_dev.client->adapter->algo->master_xfer)
 		return -EOPNOTSUPP;
-	i2c_lock_adapter(tpm_dev.client->adapter);
+	i2c_lock_segment(tpm_dev.client->adapter);
 
 	/* prepend the 'register address' to the buffer */
 	tpm_dev.buf[0] = addr;
@@ -243,7 +243,7 @@  static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
 		usleep_range(sleep_low, sleep_hi);
 	}
 
-	i2c_unlock_adapter(tpm_dev.client->adapter);
+	i2c_unlock_segment(tpm_dev.client->adapter);
 	/* take care of 'guard time' */
 	usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);