linux-kernel - Re: [PATCH v3 3/3] serial: 8250_dw: add ACPI support for uart on Hisilicon Hip05 soc

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Message-ID: <5cf24dd0-92ca-fe25-d9a0-39c4a6c52868@huawei.com>
Date:   Wed, 24 Aug 2016 16:22:58 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
CC:     <gregkh@...uxfoundation.org>, <jslaby@...e.com>,
        <linux-serial@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        <linux-acpi@...r.kernel.org>, <guohanjun@...wei.com>,
        <z.liuxinliang@...ilicon.com>, <xuwei5@...ilicon.com>,
        <graeme.gregory@...aro.org>
Subject: Re: [PATCH v3 3/3] serial: 8250_dw: add ACPI support for uart on
 Hisilicon Hip05 soc



On 2016/8/22 22:05, Heikki Krogerus wrote:
> Hi,
> 
> On Mon, Aug 22, 2016 at 02:24:14PM +0300, Andy Shevchenko wrote:
>> On Fri, 2016-07-15 at 19:01 +0800, Kefeng Wang wrote:
>>> Use built-in device properties to set device parameters for the
>>> existing device probed by acpi.
>>
>> acpi -> ACPI
>>
>>>
>>> Add ACPI identifier for UART on Hisilicon Hip05 soc, be careful
>>
>> soc -> SoC
>>
>>> that it is not 16550 compatibal, so we need set "reg-io-width"
>>
>> compatibal -> compatible

Will fix.

>>
>>> and "reg-shift" by _DSD method in DSDT.
>>>
>>> Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
>>> ---
>>>  drivers/tty/serial/8250/8250_dw.c | 23 +++++++++++++++++------
>>>  1 file changed, 17 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/tty/serial/8250/8250_dw.c
>>> b/drivers/tty/serial/8250/8250_dw.c
>>> index d6934310..5ab9cfe 100644
>>> --- a/drivers/tty/serial/8250/8250_dw.c
>>> +++ b/drivers/tty/serial/8250/8250_dw.c
>>> @@ -297,12 +297,6 @@ static void dw8250_quirks(struct uart_port *p,
>>> struct dw8250_data *data)
>>>  			p->serial_in = dw8250_serial_in32be;
>>>  			p->serial_out = dw8250_serial_out32be;
>>>  		}
>>> -	} else if (has_acpi_companion(p->dev)) {
>>> -		p->iotype = UPIO_MEM32;
>>> -		p->regshift = 2;
>>> -		p->serial_in = dw8250_serial_in32;
>>> -		/* So far none of there implement the Busy
>>> Functionality */
>>> -		data->uart_16550_compatible = true;
>>>  	}
>>>  
>>>  	/* Platforms with iDMA */
>>> @@ -352,6 +346,19 @@ static void dw8250_setup_port(struct uart_port
>>> *p)
>>>  		up->capabilities |= UART_CAP_AFE;
>>>  }
>>>  
>>> +static struct property_entry dw8250_properties[] = {
>>> +	PROPERTY_ENTRY_U32("reg-io-width", 4),
>>> +	PROPERTY_ENTRY_U32("reg-shift", 2),
>>> +	PROPERTY_ENTRY_BOOL("snps,uart-16550-compatible"),
>>> +	{ },
>>> +};
>>> +
>>> +/* non 16550 compatible id list*/
>>
>> non 16550 -> Non-16550
>> Space before */
>>
>>> +static const struct acpi_device_id non_16550_ids[] = {
>>> +	{ "HISI0031", 0 },
>>> +	{ },
>>> +};
>>> +
>>>  static int dw8250_probe(struct platform_device *pdev)
>>>  {
>>>  	struct uart_8250_port uart = {};
>>> @@ -395,6 +402,9 @@ static int dw8250_probe(struct platform_device
>>> *pdev)
>>>  	if (!data)
>>>  		return -ENOMEM;
>>>  
>>> +	if (has_acpi_companion(dev) &&
>>> !acpi_match_device(non_16550_ids, dev))
>>
>>
>>> +		platform_device_add_properties(pdev,
>>> dw8250_properties);
>>
>> What if we probe device which has already properties assigned?
>>
>> Heikki, are you good with such trick?
> 
> No this is not the way to do this. As we talked, we need to add the
> properties in the mfd drivers when they exist and not in the driver
> itself. Only if there is no mfd driver that creates the actual
> platform device for dw8250 and when also the ACPI tables don't provide
> the properties, we identify the board in dw8250_quirks and handle it
> separately. Right now there is only one such board.
> 
> I'll prepare the patches for that right now. This series can then be
> made on top of those.
> 

OK, will base on your patchset.

Thanks Andy and Heikki for your comments.

Kefeng


> 
> Thanks,
>