[U-Boot] [U-Boot PATCH 1/3] gpio: pcf8575: Add pcf8575 driver to control gpio lines

[Vignesh R <vigneshr@ti.com>]

On Tuesday 10 March 2015 09:33 PM, Tom Rini wrote:
> On Tue, Mar 10, 2015 at 08:41:21PM +0530, Vignesh R wrote:
> 
>> TI's pcf8575 is a 16-bit I2C based GPIO expander.The device features a
>> 16-bit quasi-bidirectional I/O ports. Each quasi-bidirectional I/O can
>> be used as an input or output without the use of a data-direction
>> control signal. The I/Os should be high before being used as inputs.
>>
>> This driver is based on pcf857x driver available in Linux 4.0 kernel.
>> It supports basic reading and writing of gpio pins.
> 
> For attribution of stuff ported from the kernel please see
> http://www.denx.de/wiki/view/U-Boot/Patches#Attributing_Code_Copyrights_Sign
> 
> [snip]
>> diff --git a/drivers/gpio/pcf8575.c b/drivers/gpio/pcf8575.c
>> new file mode 100644
>> index 000000000000..1ee92a29760a
>> --- /dev/null
>> +++ b/drivers/gpio/pcf8575.c
>> @@ -0,0 +1,248 @@
>> +/*
>> + * PCF8575 I2C GPIO EXPANDER DRIVER
>> + *
>> + * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
>> + *
>> + * This program is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU General Public License as
>> + * published by the Free Software Foundation version 2.
>> + *
>> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
>> + * kind, whether express or implied; without even the implied warranty
>> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + */
> 
> Please use SPDX tags for new files, thanks.
> 
> And right up front, this driver isn't using device model, please re-work
> and update to use that framework, thanks!

Thanks for reviewing.

I can switch to device model, but DRA72 does not support device tree and
hence I will not be able use device model based pcf driver in my use-case.

One approach is that, I will re-write driver to support both deprecated
gpio APIs (like gpio_get_value) and gpio device model APIs
(dm_gpio_ops). Is this approach okay? But, somebody will have to test
the dm_gpio_ops implementations as DRA72 does not support DT.

Regards
Vignesh