PCF857x and 16-bit GPIO expanders
Hi,
has anyone ever successfully using gpio-pcf857x.c driver with 16-bit gpio expanders ? We're having some issues here where toggling the last gpio pin (gpio 15) on a PCF8575 device causes platform to hang and I can't come up with any explanation of why would it hang...
Any hints ?
cheers
Signature · 1 line
balbi
Quoted 4 lines · Felipe Balbi
has anyone ever successfully using
gpio-pcf857x.cdriver with 16-bit gpio expanders ? We're having some issues here where toggling the last gpio pin (gpio 15) on a PCF8575 device causes platform to hang and I can't come up with any explanation of why would it hang...
Bouncing the question to George, Laurent and Kuninori...
Yours,
Linus Walleij
Quoted 7 lines · On Wednesday 18 September 2013 13:16:27 Linus Walleij wrote:
Quoted 4 lines · Felipe Balbi
has anyone ever successfully using
gpio-pcf857x.cdriver with 16-bit gpio expanders ? We're having some issues here where toggling the last gpio pin (gpio 15) on a PCF8575 device causes platform to hang and I can't come up with any explanation of why would it hang...Bouncing the question to George, Laurent and Kuninori...
I've got a board with a PCF8575 chip, but it uses I/Os 8 to 14 only as far as I know.
I can try toggling I/O 15, but that will need to wait until next week as I'm currently travelling without access to the hardware.
Signature · 3 lines
Regards, Laurent Pinchart
Hi,
Quoted 7 lines · Laurent Pinchart
Quoted 6 lines · On Wednesday 18 September 2013 13:16:27 Linus Walleij wrote:
Quoted 4 lines · Felipe Balbi
has anyone ever successfully using
gpio-pcf857x.cdriver with 16-bit gpio expanders ? We're having some issues here where toggling the last gpio pin (gpio 15) on a PCF8575 device causes platform to hang and I can't come up with any explanation of why would it hang...
Quoted 7 lines
Quoted 1 line
Bouncing the question to George, Laurent and Kuninori...
I've got a board with a PCF8575 chip, but it uses I/Os 8 to 14 only as far as I know.
I can try toggling I/O 15, but that will need to wait until next week as I'm currently travelling without access to the hardware.
alright, that'd help me a lot :-) Just want to make sure if we're having a board issue, or PCF8575 is a bit screwy ;-)
Thanks
Signature · 1 line
balbi
Quoted 9 lines · Felipe Balbi
Hi,
Quoted 6 lines · Laurent Pinchart
Quoted 5 lines · On Wednesday 18 September 2013 13:16:27 Linus Walleij wrote:
Quoted 4 lines · Felipe Balbi
has anyone ever successfully using
gpio-pcf857x.cdriver with 16-bit gpio expanders ? We're having some issues here where toggling the last gpio pin (gpio 15) on a PCF8575 device causes platform to hang and I can't come up with any explanation of why would it hang...
Quoted 8 lines
Quoted 6 lines
Quoted 1 line
Bouncing the question to George, Laurent and Kuninori...
I've got a board with a PCF8575 chip, but it uses I/Os 8 to 14 only as far as I know.
I can try toggling I/O 15, but that will need to wait until next week as I'm currently travelling without access to the hardware.
alright, that'd help me a lot :-) Just want to make sure if we're having a board issue, or PCF8575 is a bit screwy ;-)
Is it on dra7x-evm if so which pcf device (i2c address)? The pins i were interested were only 1 and 2 I never tried pin 15.
Just tried toggling through sysfs and it works for me.
Quoted 3 lines
Thanks
Signature · 1 line
-George
Quoted 14 lines · George Cherian
Quoted 13 lines · Felipe Balbi
Hi,
Quoted 10 lines · Laurent Pinchart
Quoted 6 lines · On Wednesday 18 September 2013 13:16:27 Linus Walleij wrote:
Quoted 4 lines · Felipe Balbi
has anyone ever successfully using
gpio-pcf857x.cdriver with 16-bit gpio expanders ? We're having some issues here where toggling the last gpio pin (gpio 15) on a PCF8575 device causes platform to hang and I can't come up with any explanation of why would it hang...Bouncing the question to George, Laurent and Kuninori...
I've got a board with a PCF8575 chip, but it uses I/Os 8 to 14 only as far as I know.
Quoted 8 lines
Quoted 4 lines
Quoted 2 lines
I can try toggling I/O 15, but that will need to wait until next week as I'm currently travelling without access to the hardware.
alright, that'd help me a lot :-) Just want to make sure if we're having a board issue, or PCF8575 is a bit screwy ;-)
Is it on dra7x-evm if so which pcf device (i2c address)? The pins i were interested were only 1 and 2 I never tried pin 15.
Just tried toggling through sysfs and it works for me.
When I look at the data sheet for PCF8575[1] Page 7, Figure 4 Write mode (output)
I see the data writes are of the order:
I2c 1's byte: address
I2c 2'nd byte:P[7-0]
I2c 3rd byte:P[17-10]
Note: bits 8,9 are missing not supported.
Now [2] claims that it does support PCF8575, however when I look at line 143[3]
unsigned bit = 1 << offset; [snip] if (value) gpio->out |= bit; else gpio->out &= ~bit;
There is no handling for the skip needed for bits 8 and 9.. Seems to me like a driver bug.
[1] http://www.ti.com/lit/ds/symlink/pcf8575.pdf
[2]
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/gpio/gpio-pcf857x.c
[3]
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/gpio/gpio-pcf857x.c#n143
Signature · 2 lines
Regards, Nishanth Menon
Quoted 22 lines · Nishanth Menon
Quoted 21 lines · George Cherian
Quoted 9 lines · Felipe Balbi
Hi,
Quoted 6 lines · Laurent Pinchart
Quoted 5 lines · On Wednesday 18 September 2013 13:16:27 Linus Walleij wrote:
Quoted 4 lines · Felipe Balbi
has anyone ever successfully using
gpio-pcf857x.cdriver with 16-bit gpio expanders ? We're having some issues here where toggling the last gpio pin (gpio 15) on a PCF8575 device causes platform to hang and I can't come up with any explanation of why would it hang...Quoted 8 lines
Quoted 6 lines
Quoted 1 line
Bouncing the question to George, Laurent and Kuninori...
I've got a board with a PCF8575 chip, but it uses I/Os 8 to 14 only as far as I know.
I can try toggling I/O 15, but that will need to wait until next week as I'm currently travelling without access to the hardware.
alright, that'd help me a lot :-) Just want to make sure if we're having a board issue, or PCF8575 is a bit screwy ;-)
Is it on dra7x-evm if so which pcf device (i2c address)? The pins i were interested were only 1 and 2 I never tried pin 15.
Quoted 7 lines
Quoted 1 line
Just tried toggling through sysfs and it works for me.
When I look at the data sheet for PCF8575[1] Page 7, Figure 4 Write mode (output)
I see the data writes are of the order:
I2c 1's byte: address
I2c 2'nd byte:P[7-0]
I2c 3rd byte:P[17-10]
I read it as an octal numbering.
Quoted 1 line
Note: bits 8,9 are missing not supported.
In octal there is no 8 and 9
Quoted 10 lines
Now [2] claims that it does support PCF8575, however when I look at line 143[3]
unsigned bit = 1 << offset; [snip] if (value) gpio->out |= bit; else gpio->out &= ~bit;
Quoted 2 lines
There is no handling for the skip needed for bits 8 and 9.. Seems to me like a driver bug.
In which case there is no driver bug
Quoted 5 lines
[1] http://www.ti.com/lit/ds/symlink/pcf8575.pdf
[2]
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/gpio/gpio-pcf857x.c
[3]
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/gpio/gpio-pcf857x.c#n143
Signature · 1 line
-George
Quoted 31 lines · George Cherian
Quoted 22 lines · Nishanth Menon
Quoted 21 lines · George Cherian
Quoted 9 lines · Felipe Balbi
Hi,
Quoted 6 lines · Laurent Pinchart
Quoted 5 lines · On Wednesday 18 September 2013 13:16:27 Linus Walleij wrote:
Quoted 4 lines · Felipe Balbi
has anyone ever successfully using
gpio-pcf857x.cdriver with 16-bit gpio expanders ? We're having some issues here where toggling the last gpio pin (gpio 15) on a PCF8575 device causes platform to hang and I can't come up with any explanation of why would it hang...Quoted 8 lines
Quoted 6 lines
Quoted 1 line
Bouncing the question to George, Laurent and Kuninori...
I've got a board with a PCF8575 chip, but it uses I/Os 8 to 14 only as far as I know.
I can try toggling I/O 15, but that will need to wait until next week as I'm currently travelling without access to the hardware.
alright, that'd help me a lot :-) Just want to make sure if we're having a board issue, or PCF8575 is a bit screwy ;-)
Is it on dra7x-evm if so which pcf device (i2c address)? The pins i were interested were only 1 and 2 I never tried pin 15.
Quoted 7 lines
Quoted 1 line
Just tried toggling through sysfs and it works for me.
When I look at the data sheet for PCF8575[1] Page 7, Figure 4 Write mode (output)
I see the data writes are of the order:
I2c 1's byte: address
I2c 2'nd byte:P[7-0]
I2c 3rd byte:P[17-10]
Quoted 4 lines
I read it as an octal numbering.
Quoted 1 line
Note: bits 8,9 are missing not supported.
In octal there is no 8 and 9
Where is octal coming into play here? P8 and 9 does not exist as per the data sheet -> look at the pinout on page 1[1] ->P00-P17 this is exactly what is described on page 2[1]:
"The number of data bytes that can be sent successively is not limited After every two bytes, the previous data is overwritten. When the PCF8575 receives the pairs of data bytes, the first byte is referred to as P07 – P00 and the second byte as P17 – P10. The third byte is referred to as P07 – P00, the fourth byte as P17 – P10, and so on"
For someone reading schematics and setting up the P15, if the person uses gpios = <&PCF8575 15 OF_GPIO_HIGH>; this will result in offset = 15, and as a result 0x80 will be send in byte 3, which from h/w point of view is P13 which could be controlling something weird!
Quoted 10 lines
Quoted 10 lines
Now [2] claims that it does support PCF8575, however when I look at line 143[3]
unsigned bit = 1 << offset; [snip] if (value) gpio->out |= bit; else gpio->out &= ~bit;
Quoted 4 lines
Quoted 2 lines
There is no handling for the skip needed for bits 8 and 9.. Seems to me like a driver bug.
In which case there is no driver bug
It probably needs clarification:
Depends on how the definition is done - to hit exact P15 in definition and to set P15, should I provide 17 as gpio number? That does not match what the h/w description is in the data sheet!
Quoted 7 lines
Signature · 6 lines
Regards, Nishanth Menon -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi,
Quoted 47 lines · Nishanth Menon
Quoted 31 lines · George Cherian
Quoted 22 lines · Nishanth Menon
Quoted 21 lines · George Cherian
Quoted 9 lines · Felipe Balbi
Hi,
Quoted 6 lines · Laurent Pinchart
Quoted 5 lines · On Wednesday 18 September 2013 13:16:27 Linus Walleij wrote:
Quoted 4 lines · Felipe Balbi
has anyone ever successfully using
gpio-pcf857x.cdriver with 16-bit gpio expanders ? We're having some issues here where toggling the last gpio pin (gpio 15) on a PCF8575 device causes platform to hang and I can't come up with any explanation of why would it hang...Quoted 8 lines
Quoted 6 lines
Quoted 1 line
Bouncing the question to George, Laurent and Kuninori...
I've got a board with a PCF8575 chip, but it uses I/Os 8 to 14 only as far as I know.
I can try toggling I/O 15, but that will need to wait until next week as I'm currently travelling without access to the hardware.
alright, that'd help me a lot :-) Just want to make sure if we're having a board issue, or PCF8575 is a bit screwy ;-)
Is it on dra7x-evm if so which pcf device (i2c address)? The pins i were interested were only 1 and 2 I never tried pin 15.
Quoted 7 lines
Quoted 1 line
Just tried toggling through sysfs and it works for me.
When I look at the data sheet for PCF8575[1] Page 7, Figure 4 Write mode (output)
I see the data writes are of the order:
I2c 1's byte: address
I2c 2'nd byte:P[7-0]
I2c 3rd byte:P[17-10]Quoted 4 lines
I read it as an octal numbering.
Quoted 1 line
Note: bits 8,9 are missing not supported.
In octal there is no 8 and 9
Where is octal coming into play here? P8 and 9 does not exist as per the data sheet -> look at the pinout on page 1[1] ->P00-P17 this is exactly what is described on page 2[1]:
"The number of data bytes that can be sent successively is not limited After every two bytes, the previous data is overwritten. When the PCF8575 receives the pairs of data bytes, the first byte is referred to as P07 – P00 and the second byte as P17 – P10. The third byte is referred to as P07 – P00, the fourth byte as P17 – P10, and so on"
Quoted 4 lines
For someone reading schematics and setting up the P15, if the person uses gpios = <&PCF8575 15
OF_GPIO_HIGH>; this will result in offset = 15, and as a result0x80will be send in byte 3, which from h/w point of view is P13 which could be controlling something weird!
you missed one detail only. I said GPIO15, not P15 :-) GPIO15 on that device is P17 ;-)
Signature · 1 line
balbi
Quoted 24 lines · George Cherian
Quoted 23 lines · Nishanth Menon
Quoted 22 lines · George Cherian
Quoted 9 lines · Felipe Balbi
Hi,
Quoted 6 lines · Laurent Pinchart
Quoted 5 lines · On Wednesday 18 September 2013 13:16:27 Linus Walleij wrote:
Quoted 4 lines · Felipe Balbi
has anyone ever successfully using
gpio-pcf857x.cdriver with 16-bit gpio expanders ? We're having some issues here where toggling the last gpio pin (gpio 15) on a PCF8575 device causes platform to hang and I can't come up with any explanation of why would it hang...Quoted 8 lines
Quoted 6 lines
Quoted 1 line
Bouncing the question to George, Laurent and Kuninori...
I've got a board with a PCF8575 chip, but it uses I/Os 8 to 14 only as far as I know.
I can try toggling I/O 15, but that will need to wait until next week as I'm currently travelling without access to the hardware.
alright, that'd help me a lot :-) Just want to make sure if we're having a board issue, or PCF8575 is a bit screwy ;-)
Is it on dra7x-evm if so which pcf device (i2c address)? The pins i were interested were only 1 and 2 I never tried pin 15.
Just tried toggling through sysfs and it works for me.
Quoted 8 lines
Quoted 6 lines
When I look at the data sheet for PCF8575[1] Page 7, Figure 4 Write mode (output)
I see the data writes are of the order:
I2c 1's byte: address
I2c 2'nd byte:P[7-0]
I2c 3rd byte:P[17-10]I read it as an octal numbering.
Kind of ... looking at the pinout, you have pins:-
P00...P07
P10...P17
So that's Port 0, bits 0..7, and Port 1, bits 0..7.
Mark J.
Hi,
Quoted 11 lines · George Cherian
Quoted 10 lines · Felipe Balbi
Hi,
Quoted 7 lines · Laurent Pinchart
Quoted 6 lines · On Wednesday 18 September 2013 13:16:27 Linus Walleij wrote:
Quoted 4 lines · Felipe Balbi
has anyone ever successfully using
gpio-pcf857x.cdriver with 16-bit gpio expanders ? We're having some issues here where toggling the last gpio pin (gpio 15) on a PCF8575 device causes platform to hang and I can't come up with any explanation of why would it hang...Bouncing the question to George, Laurent and Kuninori...
Quoted 8 lines
Quoted 7 lines
Quoted 5 lines
I've got a board with a PCF8575 chip, but it uses I/Os 8 to 14 only as far as I know.
I can try toggling I/O 15, but that will need to wait until next week as I'm currently travelling without access to the hardware.
alright, that'd help me a lot :-) Just want to make sure if we're having a board issue, or PCF8575 is a bit screwy ;-)
Is it on dra7x-evm if so which pcf device (i2c address)?
0x21 IIRC, it's pin 15 on that goes to a discrete mux. I want to toggle the mux ;-)
Signature · 1 line
balbi
A message that is not in the archive (sent off-list or not yet received): [email protected]
Hi,
Quoted 31 lines · George Cherian
Quoted 17 lines · Felipe Balbi
Hi,
Quoted 14 lines · George Cherian
Quoted 13 lines · Felipe Balbi
Hi,
Quoted 10 lines · Laurent Pinchart
Quoted 6 lines · On Wednesday 18 September 2013 13:16:27 Linus Walleij wrote:
Quoted 4 lines · Felipe Balbi
has anyone ever successfully using
gpio-pcf857x.cdriver with 16-bit gpio expanders ? We're having some issues here where toggling the last gpio pin (gpio 15) on a PCF8575 device causes platform to hang and I can't come up with any explanation of why would it hang...Bouncing the question to George, Laurent and Kuninori...
I've got a board with a PCF8575 chip, but it uses I/Os 8 to 14 only as far as I know.
Quoted 8 lines
Quoted 5 lines
Quoted 4 lines
Quoted 2 lines
I can try toggling I/O 15, but that will need to wait until next week as I'm currently travelling without access to the hardware.
alright, that'd help me a lot :-) Just want to make sure if we're having a board issue, or PCF8575 is a bit screwy ;-)
Is it on dra7x-evm if so which pcf device (i2c address)?
0x21IIRC, it's pin 15 on that goes to a discrete mux. I want to toggle the mux ;-)I am able to toggle the same via sysfs(pcf8575 @ 0x21gpio15(p17)) and it does not hang the board.
I am using Rev D1 board.Log :-
Quoted 15 lines
# cat /sys/kernel/debug/gpio . ... GPIOs 480-495, i2c/0-0021, pcf8575, can sleep: gpio-481 (id_gpio ) in hi gpio-482 (id_gpio ) in hi gpio-495 (sysfs ) out hi # echo 0 > /sys/class/gpio/gpio495/value # cat /sys/kernel/debug/gpio . ... GPIOs 480-495, i2c/0-0021, pcf8575, can sleep: gpio-481 (id_gpio ) in hi gpio-482 (id_gpio ) in hi gpio-495 (sysfs ) out lo
weird... I'll debug here and see if I can still reproduce with v3.12-rc1. Thanks anyway :-)
cheers
Signature · 1 line
balbi