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Groups > linux.kernel > #1264801 > unrolled thread

[PATCH v2 1/3] tty: Introduce UART_CAP_HW485

Started by"Matwey V. Kornilov" <matwey@sai.msu.ru>
First post2015-11-07 11:20 +0100
Last post2015-11-07 23:10 +0100
Articles 6 — 2 participants

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  [PATCH v2 1/3] tty: Introduce UART_CAP_HW485 "Matwey V. Kornilov" <matwey@sai.msu.ru> - 2015-11-07 11:20 +0100
    Re: [PATCH v2 1/3] tty: Introduce UART_CAP_HW485 Peter Hurley <peter@hurleysoftware.com> - 2015-11-07 13:30 +0100
      Re: [PATCH v2 1/3] tty: Introduce UART_CAP_HW485 "Matwey V. Kornilov" <matwey@sai.msu.ru> - 2015-11-07 13:50 +0100
        Re: [PATCH v2 1/3] tty: Introduce UART_CAP_HW485 Peter Hurley <peter@hurleysoftware.com> - 2015-11-07 16:40 +0100
          Re: [PATCH v2 1/3] tty: Introduce UART_CAP_HW485 "Matwey V. Kornilov" <matwey@sai.msu.ru> - 2015-11-07 22:20 +0100
            Re: [PATCH v2 1/3] tty: Introduce UART_CAP_HW485 Peter Hurley <peter@hurleysoftware.com> - 2015-11-07 23:10 +0100

#1264801 — [PATCH v2 1/3] tty: Introduce UART_CAP_HW485

From"Matwey V. Kornilov" <matwey@sai.msu.ru>
Date2015-11-07 11:20 +0100
Subject[PATCH v2 1/3] tty: Introduce UART_CAP_HW485
Message-ID<qs8Lf-XB-5@gated-at.bofh.it>
Introduce new capability UART_CAP_HW485 to mark 8250 UARTs which have
hardware support of line direction control.

Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
---
Changes since v1:
 - Commit message has been wrapped

 drivers/tty/serial/8250/8250.h         | 1 +
 drivers/tty/serial/8250/8250_fintek.c  | 1 +
 drivers/tty/serial/8250/8250_lpc18xx.c | 1 +
 drivers/tty/serial/8250/8250_pci.c     | 1 +
 4 files changed, 4 insertions(+)

diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index d54dcd8..92a4f47 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -69,6 +69,7 @@ struct serial8250_config {
 	unsigned int	flags;
 };
 
+#define UART_CAP_HW485	(1 << 7)	/* UART has hardware direction control for RS485 */
 #define UART_CAP_FIFO	(1 << 8)	/* UART has FIFO */
 #define UART_CAP_EFR	(1 << 9)	/* UART has EFR */
 #define UART_CAP_SLEEP	(1 << 10)	/* UART has IER sleep */
diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c
index 8947439..f2831a8 100644
--- a/drivers/tty/serial/8250/8250_fintek.c
+++ b/drivers/tty/serial/8250/8250_fintek.c
@@ -208,6 +208,7 @@ fintek_8250_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
 	uart.port.iobase = pnp_port_start(dev, 0);
 	uart.port.iotype = UPIO_PORT;
 	uart.port.rs485_config = fintek_8250_rs485_config;
+	uart.capabilities = UART_CAP_HW485;
 
 	uart.port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
 	if (pnp_irq_flags(dev, 0) & IORESOURCE_IRQ_SHAREABLE)
diff --git a/drivers/tty/serial/8250/8250_lpc18xx.c b/drivers/tty/serial/8250/8250_lpc18xx.c
index 99cd478..9d30276 100644
--- a/drivers/tty/serial/8250/8250_lpc18xx.c
+++ b/drivers/tty/serial/8250/8250_lpc18xx.c
@@ -175,6 +175,7 @@ static int lpc18xx_serial_probe(struct platform_device *pdev)
 	uart.port.private_data = data;
 	uart.port.rs485_config = lpc18xx_rs485_config;
 	uart.port.serial_out = lpc18xx_uart_serial_out;
+	uart.capabilities = UART_CAP_HW485;
 
 	uart.dma = &data->dma;
 	uart.dma->rxconf.src_maxburst = 1;
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 4097f3f..c7c0ae9 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1599,6 +1599,7 @@ static int pci_fintek_setup(struct serial_private *priv,
 	port->port.iotype = UPIO_PORT;
 	port->port.iobase = iobase;
 	port->port.rs485_config = pci_fintek_rs485_config;
+	port->capabilities = UART_CAP_HW485;
 
 	data = devm_kzalloc(&pdev->dev, sizeof(u8), GFP_KERNEL);
 	if (!data)
-- 
2.6.2

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#1264831

FromPeter Hurley <peter@hurleysoftware.com>
Date2015-11-07 13:30 +0100
Message-ID<qsaN4-2eE-15@gated-at.bofh.it>
In reply to#1264801
On 11/07/2015 05:09 AM, Matwey V. Kornilov wrote:
> Introduce new capability UART_CAP_HW485 to mark 8250 UARTs which have
> hardware support of line direction control.

Since capabilities are not exported to user-space, how will user-space
know if the port only provides emulated 485 (eg., where only HW485 is
acceptable)?

Regards,
Peter Hurley

> Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
> ---
> Changes since v1:
>  - Commit message has been wrapped
> 
>  drivers/tty/serial/8250/8250.h         | 1 +
>  drivers/tty/serial/8250/8250_fintek.c  | 1 +
>  drivers/tty/serial/8250/8250_lpc18xx.c | 1 +
>  drivers/tty/serial/8250/8250_pci.c     | 1 +
>  4 files changed, 4 insertions(+)
> 
> diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
> index d54dcd8..92a4f47 100644
> --- a/drivers/tty/serial/8250/8250.h
> +++ b/drivers/tty/serial/8250/8250.h
> @@ -69,6 +69,7 @@ struct serial8250_config {
>  	unsigned int	flags;
>  };
>  
> +#define UART_CAP_HW485	(1 << 7)	/* UART has hardware direction control for RS485 */
>  #define UART_CAP_FIFO	(1 << 8)	/* UART has FIFO */
>  #define UART_CAP_EFR	(1 << 9)	/* UART has EFR */
>  #define UART_CAP_SLEEP	(1 << 10)	/* UART has IER sleep */
> diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c
> index 8947439..f2831a8 100644
> --- a/drivers/tty/serial/8250/8250_fintek.c
> +++ b/drivers/tty/serial/8250/8250_fintek.c
> @@ -208,6 +208,7 @@ fintek_8250_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
>  	uart.port.iobase = pnp_port_start(dev, 0);
>  	uart.port.iotype = UPIO_PORT;
>  	uart.port.rs485_config = fintek_8250_rs485_config;
> +	uart.capabilities = UART_CAP_HW485;
>  
>  	uart.port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
>  	if (pnp_irq_flags(dev, 0) & IORESOURCE_IRQ_SHAREABLE)
> diff --git a/drivers/tty/serial/8250/8250_lpc18xx.c b/drivers/tty/serial/8250/8250_lpc18xx.c
> index 99cd478..9d30276 100644
> --- a/drivers/tty/serial/8250/8250_lpc18xx.c
> +++ b/drivers/tty/serial/8250/8250_lpc18xx.c
> @@ -175,6 +175,7 @@ static int lpc18xx_serial_probe(struct platform_device *pdev)
>  	uart.port.private_data = data;
>  	uart.port.rs485_config = lpc18xx_rs485_config;
>  	uart.port.serial_out = lpc18xx_uart_serial_out;
> +	uart.capabilities = UART_CAP_HW485;
>  
>  	uart.dma = &data->dma;
>  	uart.dma->rxconf.src_maxburst = 1;
> diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
> index 4097f3f..c7c0ae9 100644
> --- a/drivers/tty/serial/8250/8250_pci.c
> +++ b/drivers/tty/serial/8250/8250_pci.c
> @@ -1599,6 +1599,7 @@ static int pci_fintek_setup(struct serial_private *priv,
>  	port->port.iotype = UPIO_PORT;
>  	port->port.iobase = iobase;
>  	port->port.rs485_config = pci_fintek_rs485_config;
> +	port->capabilities = UART_CAP_HW485;
>  
>  	data = devm_kzalloc(&pdev->dev, sizeof(u8), GFP_KERNEL);
>  	if (!data)
> 

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#1264833

From"Matwey V. Kornilov" <matwey@sai.msu.ru>
Date2015-11-07 13:50 +0100
Message-ID<qsb6p-2m4-7@gated-at.bofh.it>
In reply to#1264831
2015-11-07 15:22 GMT+03:00 Peter Hurley <peter@hurleysoftware.com>:
> On 11/07/2015 05:09 AM, Matwey V. Kornilov wrote:
>> Introduce new capability UART_CAP_HW485 to mark 8250 UARTs which have
>> hardware support of line direction control.
>
> Since capabilities are not exported to user-space, how will user-space
> know if the port only provides emulated 485 (eg., where only HW485 is
> acceptable)?

I cannot imagine the case when user really has to care about
implementation details.
In both cases the user will be provided with the consistent API
(TIOCGRS485/TIOCSRS485 ioctls) resulting into the same behavior.
Could you please expand your question?

>
> Regards,
> Peter Hurley
>
>> Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
>> ---
>> Changes since v1:
>>  - Commit message has been wrapped
>>
>>  drivers/tty/serial/8250/8250.h         | 1 +
>>  drivers/tty/serial/8250/8250_fintek.c  | 1 +
>>  drivers/tty/serial/8250/8250_lpc18xx.c | 1 +
>>  drivers/tty/serial/8250/8250_pci.c     | 1 +
>>  4 files changed, 4 insertions(+)
>>
>> diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
>> index d54dcd8..92a4f47 100644
>> --- a/drivers/tty/serial/8250/8250.h
>> +++ b/drivers/tty/serial/8250/8250.h
>> @@ -69,6 +69,7 @@ struct serial8250_config {
>>       unsigned int    flags;
>>  };
>>
>> +#define UART_CAP_HW485       (1 << 7)        /* UART has hardware direction control for RS485 */
>>  #define UART_CAP_FIFO        (1 << 8)        /* UART has FIFO */
>>  #define UART_CAP_EFR (1 << 9)        /* UART has EFR */
>>  #define UART_CAP_SLEEP       (1 << 10)       /* UART has IER sleep */
>> diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c
>> index 8947439..f2831a8 100644
>> --- a/drivers/tty/serial/8250/8250_fintek.c
>> +++ b/drivers/tty/serial/8250/8250_fintek.c
>> @@ -208,6 +208,7 @@ fintek_8250_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
>>       uart.port.iobase = pnp_port_start(dev, 0);
>>       uart.port.iotype = UPIO_PORT;
>>       uart.port.rs485_config = fintek_8250_rs485_config;
>> +     uart.capabilities = UART_CAP_HW485;
>>
>>       uart.port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
>>       if (pnp_irq_flags(dev, 0) & IORESOURCE_IRQ_SHAREABLE)
>> diff --git a/drivers/tty/serial/8250/8250_lpc18xx.c b/drivers/tty/serial/8250/8250_lpc18xx.c
>> index 99cd478..9d30276 100644
>> --- a/drivers/tty/serial/8250/8250_lpc18xx.c
>> +++ b/drivers/tty/serial/8250/8250_lpc18xx.c
>> @@ -175,6 +175,7 @@ static int lpc18xx_serial_probe(struct platform_device *pdev)
>>       uart.port.private_data = data;
>>       uart.port.rs485_config = lpc18xx_rs485_config;
>>       uart.port.serial_out = lpc18xx_uart_serial_out;
>> +     uart.capabilities = UART_CAP_HW485;
>>
>>       uart.dma = &data->dma;
>>       uart.dma->rxconf.src_maxburst = 1;
>> diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
>> index 4097f3f..c7c0ae9 100644
>> --- a/drivers/tty/serial/8250/8250_pci.c
>> +++ b/drivers/tty/serial/8250/8250_pci.c
>> @@ -1599,6 +1599,7 @@ static int pci_fintek_setup(struct serial_private *priv,
>>       port->port.iotype = UPIO_PORT;
>>       port->port.iobase = iobase;
>>       port->port.rs485_config = pci_fintek_rs485_config;
>> +     port->capabilities = UART_CAP_HW485;
>>
>>       data = devm_kzalloc(&pdev->dev, sizeof(u8), GFP_KERNEL);
>>       if (!data)
>>
>



-- 
With best regards,
Matwey V. Kornilov.
Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia
119991, Moscow, Universitetsky pr-k 13, +7 (495) 9392382
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#1264866

FromPeter Hurley <peter@hurleysoftware.com>
Date2015-11-07 16:40 +0100
Message-ID<qsdKX-45U-43@gated-at.bofh.it>
In reply to#1264833
On 11/07/2015 07:39 AM, Matwey V. Kornilov wrote:
> 2015-11-07 15:22 GMT+03:00 Peter Hurley <peter@hurleysoftware.com>:
>> On 11/07/2015 05:09 AM, Matwey V. Kornilov wrote:
>>> Introduce new capability UART_CAP_HW485 to mark 8250 UARTs which have
>>> hardware support of line direction control.
>>
>> Since capabilities are not exported to user-space, how will user-space
>> know if the port only provides emulated 485 (eg., where only HW485 is
>> acceptable)?
> 
> I cannot imagine the case when user really has to care about
> implementation details.
> In both cases the user will be provided with the consistent API
> (TIOCGRS485/TIOCSRS485 ioctls) resulting into the same behavior.
> Could you please expand your question?

Well, the entire serial core is a 'consistent' API but yet we
still report to user-space what the port type is. Same with lspci
and lsusb.

Regards,
Peter Hurley


>>> Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
>>> ---
>>> Changes since v1:
>>>  - Commit message has been wrapped
>>>
>>>  drivers/tty/serial/8250/8250.h         | 1 +
>>>  drivers/tty/serial/8250/8250_fintek.c  | 1 +
>>>  drivers/tty/serial/8250/8250_lpc18xx.c | 1 +
>>>  drivers/tty/serial/8250/8250_pci.c     | 1 +
>>>  4 files changed, 4 insertions(+)
>>>
>>> diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
>>> index d54dcd8..92a4f47 100644
>>> --- a/drivers/tty/serial/8250/8250.h
>>> +++ b/drivers/tty/serial/8250/8250.h
>>> @@ -69,6 +69,7 @@ struct serial8250_config {
>>>       unsigned int    flags;
>>>  };
>>>
>>> +#define UART_CAP_HW485       (1 << 7)        /* UART has hardware direction control for RS485 */
>>>  #define UART_CAP_FIFO        (1 << 8)        /* UART has FIFO */
>>>  #define UART_CAP_EFR (1 << 9)        /* UART has EFR */
>>>  #define UART_CAP_SLEEP       (1 << 10)       /* UART has IER sleep */
>>> diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c
>>> index 8947439..f2831a8 100644
>>> --- a/drivers/tty/serial/8250/8250_fintek.c
>>> +++ b/drivers/tty/serial/8250/8250_fintek.c
>>> @@ -208,6 +208,7 @@ fintek_8250_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
>>>       uart.port.iobase = pnp_port_start(dev, 0);
>>>       uart.port.iotype = UPIO_PORT;
>>>       uart.port.rs485_config = fintek_8250_rs485_config;
>>> +     uart.capabilities = UART_CAP_HW485;
>>>
>>>       uart.port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
>>>       if (pnp_irq_flags(dev, 0) & IORESOURCE_IRQ_SHAREABLE)
>>> diff --git a/drivers/tty/serial/8250/8250_lpc18xx.c b/drivers/tty/serial/8250/8250_lpc18xx.c
>>> index 99cd478..9d30276 100644
>>> --- a/drivers/tty/serial/8250/8250_lpc18xx.c
>>> +++ b/drivers/tty/serial/8250/8250_lpc18xx.c
>>> @@ -175,6 +175,7 @@ static int lpc18xx_serial_probe(struct platform_device *pdev)
>>>       uart.port.private_data = data;
>>>       uart.port.rs485_config = lpc18xx_rs485_config;
>>>       uart.port.serial_out = lpc18xx_uart_serial_out;
>>> +     uart.capabilities = UART_CAP_HW485;
>>>
>>>       uart.dma = &data->dma;
>>>       uart.dma->rxconf.src_maxburst = 1;
>>> diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
>>> index 4097f3f..c7c0ae9 100644
>>> --- a/drivers/tty/serial/8250/8250_pci.c
>>> +++ b/drivers/tty/serial/8250/8250_pci.c
>>> @@ -1599,6 +1599,7 @@ static int pci_fintek_setup(struct serial_private *priv,
>>>       port->port.iotype = UPIO_PORT;
>>>       port->port.iobase = iobase;
>>>       port->port.rs485_config = pci_fintek_rs485_config;
>>> +     port->capabilities = UART_CAP_HW485;
>>>
>>>       data = devm_kzalloc(&pdev->dev, sizeof(u8), GFP_KERNEL);
>>>       if (!data)
>>>
>>
> 
> 
> 

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#1264936

From"Matwey V. Kornilov" <matwey@sai.msu.ru>
Date2015-11-07 22:20 +0100
Message-ID<qsj3X-7AY-9@gated-at.bofh.it>
In reply to#1264866
2015-11-07 18:32 GMT+03:00 Peter Hurley <peter@hurleysoftware.com>:
> On 11/07/2015 07:39 AM, Matwey V. Kornilov wrote:
>> 2015-11-07 15:22 GMT+03:00 Peter Hurley <peter@hurleysoftware.com>:
>>> On 11/07/2015 05:09 AM, Matwey V. Kornilov wrote:
>>>> Introduce new capability UART_CAP_HW485 to mark 8250 UARTs which have
>>>> hardware support of line direction control.
>>>
>>> Since capabilities are not exported to user-space, how will user-space
>>> know if the port only provides emulated 485 (eg., where only HW485 is
>>> acceptable)?
>>
>> I cannot imagine the case when user really has to care about
>> implementation details.
>> In both cases the user will be provided with the consistent API
>> (TIOCGRS485/TIOCSRS485 ioctls) resulting into the same behavior.
>> Could you please expand your question?
>
> Well, the entire serial core is a 'consistent' API but yet we
> still report to user-space what the port type is. Same with lspci
> and lsusb.

Yes, that is correct.
I mean if you want the knowledge about HW485 be provided to the
user-space via some ioctl, then I cannot understand what application
is going to do with it.
It has single one option: use provided RS485 if it needs RS485, it
cannot purchase and install other hardware in runtime.
But I think we could add new read-only flag to struct serial_rs485,
say SER_RS485_SOFTWARE then user will know that software emulation is
being used.
Would it be ok?

>
> Regards,
> Peter Hurley
>
>
>>>> Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
>>>> ---
>>>> Changes since v1:
>>>>  - Commit message has been wrapped
>>>>
>>>>  drivers/tty/serial/8250/8250.h         | 1 +
>>>>  drivers/tty/serial/8250/8250_fintek.c  | 1 +
>>>>  drivers/tty/serial/8250/8250_lpc18xx.c | 1 +
>>>>  drivers/tty/serial/8250/8250_pci.c     | 1 +
>>>>  4 files changed, 4 insertions(+)
>>>>
>>>> diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
>>>> index d54dcd8..92a4f47 100644
>>>> --- a/drivers/tty/serial/8250/8250.h
>>>> +++ b/drivers/tty/serial/8250/8250.h
>>>> @@ -69,6 +69,7 @@ struct serial8250_config {
>>>>       unsigned int    flags;
>>>>  };
>>>>
>>>> +#define UART_CAP_HW485       (1 << 7)        /* UART has hardware direction control for RS485 */
>>>>  #define UART_CAP_FIFO        (1 << 8)        /* UART has FIFO */
>>>>  #define UART_CAP_EFR (1 << 9)        /* UART has EFR */
>>>>  #define UART_CAP_SLEEP       (1 << 10)       /* UART has IER sleep */
>>>> diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c
>>>> index 8947439..f2831a8 100644
>>>> --- a/drivers/tty/serial/8250/8250_fintek.c
>>>> +++ b/drivers/tty/serial/8250/8250_fintek.c
>>>> @@ -208,6 +208,7 @@ fintek_8250_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
>>>>       uart.port.iobase = pnp_port_start(dev, 0);
>>>>       uart.port.iotype = UPIO_PORT;
>>>>       uart.port.rs485_config = fintek_8250_rs485_config;
>>>> +     uart.capabilities = UART_CAP_HW485;
>>>>
>>>>       uart.port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
>>>>       if (pnp_irq_flags(dev, 0) & IORESOURCE_IRQ_SHAREABLE)
>>>> diff --git a/drivers/tty/serial/8250/8250_lpc18xx.c b/drivers/tty/serial/8250/8250_lpc18xx.c
>>>> index 99cd478..9d30276 100644
>>>> --- a/drivers/tty/serial/8250/8250_lpc18xx.c
>>>> +++ b/drivers/tty/serial/8250/8250_lpc18xx.c
>>>> @@ -175,6 +175,7 @@ static int lpc18xx_serial_probe(struct platform_device *pdev)
>>>>       uart.port.private_data = data;
>>>>       uart.port.rs485_config = lpc18xx_rs485_config;
>>>>       uart.port.serial_out = lpc18xx_uart_serial_out;
>>>> +     uart.capabilities = UART_CAP_HW485;
>>>>
>>>>       uart.dma = &data->dma;
>>>>       uart.dma->rxconf.src_maxburst = 1;
>>>> diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
>>>> index 4097f3f..c7c0ae9 100644
>>>> --- a/drivers/tty/serial/8250/8250_pci.c
>>>> +++ b/drivers/tty/serial/8250/8250_pci.c
>>>> @@ -1599,6 +1599,7 @@ static int pci_fintek_setup(struct serial_private *priv,
>>>>       port->port.iotype = UPIO_PORT;
>>>>       port->port.iobase = iobase;
>>>>       port->port.rs485_config = pci_fintek_rs485_config;
>>>> +     port->capabilities = UART_CAP_HW485;
>>>>
>>>>       data = devm_kzalloc(&pdev->dev, sizeof(u8), GFP_KERNEL);
>>>>       if (!data)
>>>>
>>>
>>
>>
>>
>



-- 
With best regards,
Matwey V. Kornilov.
Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia
119991, Moscow, Universitetsky pr-k 13, +7 (495) 9392382
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#1264939

FromPeter Hurley <peter@hurleysoftware.com>
Date2015-11-07 23:10 +0100
Message-ID<qsjQm-874-9@gated-at.bofh.it>
In reply to#1264936
On 11/07/2015 04:10 PM, Matwey V. Kornilov wrote:
> 2015-11-07 18:32 GMT+03:00 Peter Hurley <peter@hurleysoftware.com>:
>> On 11/07/2015 07:39 AM, Matwey V. Kornilov wrote:
>>> 2015-11-07 15:22 GMT+03:00 Peter Hurley <peter@hurleysoftware.com>:
>>>> On 11/07/2015 05:09 AM, Matwey V. Kornilov wrote:
>>>>> Introduce new capability UART_CAP_HW485 to mark 8250 UARTs which have
>>>>> hardware support of line direction control.
>>>>
>>>> Since capabilities are not exported to user-space, how will user-space
>>>> know if the port only provides emulated 485 (eg., where only HW485 is
>>>> acceptable)?
>>>
>>> I cannot imagine the case when user really has to care about
>>> implementation details.
>>> In both cases the user will be provided with the consistent API
>>> (TIOCGRS485/TIOCSRS485 ioctls) resulting into the same behavior.
>>> Could you please expand your question?
>>
>> Well, the entire serial core is a 'consistent' API but yet we
>> still report to user-space what the port type is. Same with lspci
>> and lsusb.
> 
> Yes, that is correct.
> I mean if you want the knowledge about HW485 be provided to the
> user-space via some ioctl, then I cannot understand what application
> is going to do with it.
> It has single one option: use provided RS485 if it needs RS485, it
> cannot purchase and install other hardware in runtime.
> But I think we could add new read-only flag to struct serial_rs485,
> say SER_RS485_SOFTWARE then user will know that software emulation is
> being used.
> Would it be ok?

Yes, something like that would be fine.

Regards,
Peter Hurley


>>>>> Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
>>>>> ---
>>>>> Changes since v1:
>>>>>  - Commit message has been wrapped
>>>>>
>>>>>  drivers/tty/serial/8250/8250.h         | 1 +
>>>>>  drivers/tty/serial/8250/8250_fintek.c  | 1 +
>>>>>  drivers/tty/serial/8250/8250_lpc18xx.c | 1 +
>>>>>  drivers/tty/serial/8250/8250_pci.c     | 1 +
>>>>>  4 files changed, 4 insertions(+)
>>>>>
>>>>> diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
>>>>> index d54dcd8..92a4f47 100644
>>>>> --- a/drivers/tty/serial/8250/8250.h
>>>>> +++ b/drivers/tty/serial/8250/8250.h
>>>>> @@ -69,6 +69,7 @@ struct serial8250_config {
>>>>>       unsigned int    flags;
>>>>>  };
>>>>>
>>>>> +#define UART_CAP_HW485       (1 << 7)        /* UART has hardware direction control for RS485 */
>>>>>  #define UART_CAP_FIFO        (1 << 8)        /* UART has FIFO */
>>>>>  #define UART_CAP_EFR (1 << 9)        /* UART has EFR */
>>>>>  #define UART_CAP_SLEEP       (1 << 10)       /* UART has IER sleep */
>>>>> diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c
>>>>> index 8947439..f2831a8 100644
>>>>> --- a/drivers/tty/serial/8250/8250_fintek.c
>>>>> +++ b/drivers/tty/serial/8250/8250_fintek.c
>>>>> @@ -208,6 +208,7 @@ fintek_8250_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
>>>>>       uart.port.iobase = pnp_port_start(dev, 0);
>>>>>       uart.port.iotype = UPIO_PORT;
>>>>>       uart.port.rs485_config = fintek_8250_rs485_config;
>>>>> +     uart.capabilities = UART_CAP_HW485;
>>>>>
>>>>>       uart.port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
>>>>>       if (pnp_irq_flags(dev, 0) & IORESOURCE_IRQ_SHAREABLE)
>>>>> diff --git a/drivers/tty/serial/8250/8250_lpc18xx.c b/drivers/tty/serial/8250/8250_lpc18xx.c
>>>>> index 99cd478..9d30276 100644
>>>>> --- a/drivers/tty/serial/8250/8250_lpc18xx.c
>>>>> +++ b/drivers/tty/serial/8250/8250_lpc18xx.c
>>>>> @@ -175,6 +175,7 @@ static int lpc18xx_serial_probe(struct platform_device *pdev)
>>>>>       uart.port.private_data = data;
>>>>>       uart.port.rs485_config = lpc18xx_rs485_config;
>>>>>       uart.port.serial_out = lpc18xx_uart_serial_out;
>>>>> +     uart.capabilities = UART_CAP_HW485;
>>>>>
>>>>>       uart.dma = &data->dma;
>>>>>       uart.dma->rxconf.src_maxburst = 1;
>>>>> diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
>>>>> index 4097f3f..c7c0ae9 100644
>>>>> --- a/drivers/tty/serial/8250/8250_pci.c
>>>>> +++ b/drivers/tty/serial/8250/8250_pci.c
>>>>> @@ -1599,6 +1599,7 @@ static int pci_fintek_setup(struct serial_private *priv,
>>>>>       port->port.iotype = UPIO_PORT;
>>>>>       port->port.iobase = iobase;
>>>>>       port->port.rs485_config = pci_fintek_rs485_config;
>>>>> +     port->capabilities = UART_CAP_HW485;
>>>>>
>>>>>       data = devm_kzalloc(&pdev->dev, sizeof(u8), GFP_KERNEL);
>>>>>       if (!data)

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