Re: [PATCH 2/3] Phy: Exynos: Add Exynos5250 sata phy driver

[Kishon Vijay Abraham I <kishon@ti.com>]

On Tuesday 19 November 2013 03:42 PM, Yuvaraj Kumar wrote:
> On Tue, Nov 19, 2013 at 3:22 PM, Kishon Vijay Abraham I <kishon@ti.com> wrote:
>> On Friday 15 November 2013 11:17 AM, Yuvaraj Kumar wrote:
>>> On Thu, Nov 14, 2013 at 11:18 AM, Kishon Vijay Abraham I <kishon@ti.com> wrote:
>>>> Hi,
>>>>
>>>> On Monday 07 October 2013 07:35 PM, Yuvaraj Cd wrote:
>>>>> On Tue, Oct 1, 2013 at 6:21 PM, Kishon Vijay Abraham I <kishon@ti.com> wrote:
>>>>>> On Tuesday 01 October 2013 12:03 PM, Yuvaraj Kumar C D wrote:
>>>>>>> This patch adds the sata phy driver for Exynos5250.Exynos5250 sata
>>>>>>> phy comprises of CMU and TRSV blocks which are of I2C register Map.
>>>>>>> So this patch also adds a i2c client driver, which is used configure
>>>>>>> the CMU and TRSV block of exynos5250 SATA PHY.
>>>>>>
>>>>>> Why not make the Exynos5250 sata phy as a i2c client driver instead?
>>>>>>>
>>>>>>> This patch incorporates the generic phy framework to deal with sata
>>>>>>> phy.
>>>>>>>
>>>>>>> This patch depends on the below patch
>>>>>>>       [1].drivers: phy: add generic PHY framework
>>>>>>>               by Kishon Vijay Abraham I<kishon@ti.com>
>>>>>>>
>>>>>>> Signed-off-by: Yuvaraj Kumar C D <yuvaraj.cd@samsung.com>
>>>>>>> Signed-off-by: Girish K S <ks.giri@samsung.com>
>>>>>>> Signed-off-by: Vasanth Ananthan <vasanth.a@samsung.com>
>>>>>>> ---
>>>>>>>  drivers/phy/Kconfig                      |    6 +
>>>>>>>  drivers/phy/Makefile                     |    1 +
>>>>>>>  drivers/phy/exynos/Kconfig               |    5 +
>>>>>>>  drivers/phy/exynos/Makefile              |    5 +
>>>>>>>  drivers/phy/exynos/exynos5250_phy_i2c.c  |   53 +++++++
>>>>>>>  drivers/phy/exynos/sata_phy_exynos5250.c |  248 ++++++++++++++++++++++++++++++
>>>>>>>  drivers/phy/exynos/sata_phy_exynos5250.h |   33 ++++
>>>>>>>  7 files changed, 351 insertions(+)
>>>>>>>  create mode 100644 drivers/phy/exynos/Kconfig
>>>>>>>  create mode 100644 drivers/phy/exynos/Makefile
>>>>>>>  create mode 100644 drivers/phy/exynos/exynos5250_phy_i2c.c
>>>>>>>  create mode 100644 drivers/phy/exynos/sata_phy_exynos5250.c
>>>>>>>  create mode 100644 drivers/phy/exynos/sata_phy_exynos5250.h
>>>>>>>
>>>>>>> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
>>>>>>> index 5f85909..ab3d1c6 100644
>>>>>>> --- a/drivers/phy/Kconfig
>>>>>>> +++ b/drivers/phy/Kconfig
>>>>>>> @@ -11,3 +11,9 @@ menuconfig GENERIC_PHY
>>>>>>>         devices present in the kernel. This layer will have the generic
>>>>>>>         API by which phy drivers can create PHY using the phy framework and
>>>>>>>         phy users can obtain reference to the PHY.
>>>>>>> +
>>>>>>> +if GENERIC_PHY
>>>>>>
>>>>>> NAK. Just select GENERIC_PHY from your driver Kconfig.
>>>>>>> +
>>>>>>> +source "drivers/phy/exynos/Kconfig"
>>>>>>> +
>>>>>>> +endif
>>>>>>> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
>>>>>>> index 9e9560f..e0223d7 100644
>>>>>>> --- a/drivers/phy/Makefile
>>>>>>> +++ b/drivers/phy/Makefile
>>>>>>> @@ -3,3 +3,4 @@
>>>>>>>  #
>>>>>>>
>>>>>>>  obj-$(CONFIG_GENERIC_PHY)    += phy-core.o
>>>>>>> +obj-$(CONFIG_PHY_SAMSUNG_SATA)       += exynos/
>>>>>>
>>>>>> simply have phy-exynos5250 in drivers/phy.
>>>>> ok.
>>>>>>> diff --git a/drivers/phy/exynos/Kconfig b/drivers/phy/exynos/Kconfig
>>>>>>> new file mode 100644
>>>>>>> index 0000000..fa125fb
>>>>>>> --- /dev/null
>>>>>>> +++ b/drivers/phy/exynos/Kconfig
>>>>>>> @@ -0,0 +1,5 @@
>>>>>>> +config PHY_SAMSUNG_SATA
>>>>>>> +     tristate "Samsung Sata SerDes/PHY driver"
>>>>>>> +     help
>>>>>>> +       Support for Samsung sata SerDes/Phy found on Samsung
>>>>>>> +       SoCs.
>>>>>>> diff --git a/drivers/phy/exynos/Makefile b/drivers/phy/exynos/Makefile
>>>>>>> new file mode 100644
>>>>>>> index 0000000..50dc7eb
>>>>>>> --- /dev/null
>>>>>>> +++ b/drivers/phy/exynos/Makefile
>>>>>>> @@ -0,0 +1,5 @@
>>>>>>> +#
>>>>>>> +# Makefile for the exynos phy drivers.
>>>>>>> +#
>>>>>>> +ccflags-y := -Idrivers/phy/exynos
>>>>>>> +obj-$(CONFIG_PHY_SAMSUNG_SATA)       += sata_phy_exynos5250.o exynos5250_phy_i2c.o
>>>>>>> diff --git a/drivers/phy/exynos/exynos5250_phy_i2c.c b/drivers/phy/exynos/exynos5250_phy_i2c.c
>>>>>>> new file mode 100644
>>>>>>> index 0000000..9c75d3b
>>>>>>> --- /dev/null
>>>>>>> +++ b/drivers/phy/exynos/exynos5250_phy_i2c.c
>>>>>>> @@ -0,0 +1,53 @@
>>>>>>> +/*
>>>>>>> + * Copyright (C) 2013 Samsung Electronics Co.Ltd
>>>>>>> + * Author:
>>>>>>> + *   Yuvaraj C D <yuvaraj.cd@samsung.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;  either version 2 of the  License, or (at your
>>>>>>> + * option) any later version.
>>>>>>> + *
>>>>>>> + */
>>>>>>> +
>>>>>>> +#include <linux/kernel.h>
>>>>>>> +#include <linux/i2c.h>
>>>>>>> +#include <linux/module.h>
>>>>>>> +#include "sata_phy_exynos5250.h"
>>>>>>> +
>>>>>>> +static int exynos_sata_i2c_probe(struct i2c_client *client,
>>>>>>> +             const struct i2c_device_id *i2c_id)
>>>>>>> +{
>>>>>>> +     sataphy_attach_i2c_client(client);
>>>>>>> +
>>>>>>> +     dev_info(&client->adapter->dev,
>>>>>>> +             "attached %s into i2c adapter successfully\n",
>>>>>>> +             client->name);
>>>>>>> +
>>>>>>> +     return 0;
>>>>>>> +}
>>>>>>> +
>>>>>>> +static int exynos_sata_i2c_remove(struct i2c_client *client)
>>>>>>> +{
>>>>>>> +     dev_info(&client->adapter->dev,
>>>>>>> +             "detached %s from i2c adapter successfully\n",
>>>>>>> +             client->name);
>>>>>>> +
>>>>>>> +     return 0;
>>>>>>> +}
>>>>>>> +
>>>>>>> +static const struct i2c_device_id phy_i2c_device_match[] = {
>>>>>>> +     { "sata-phy-i2c", 0 },
>>>>>>> +};
>>>>>>> +MODULE_DEVICE_TABLE(of, phy_i2c_device_match);
>>>>>>> +
>>>>>>> +struct i2c_driver sataphy_i2c_driver = {
>>>>>>> +     .probe    = exynos_sata_i2c_probe,
>>>>>>> +     .id_table = phy_i2c_device_match,
>>>>>>> +     .remove         = exynos_sata_i2c_remove,
>>>>>>> +     .driver   = {
>>>>>>> +             .name = "sata-phy-i2c",
>>>>>>> +             .owner = THIS_MODULE,
>>>>>>> +             .of_match_table = (void *)phy_i2c_device_match,
>>>>>>> +             },
>>>>>>> +};
>>>>>>
>>>>>> As I just mentioned above, we can merge this driver with the below one.
>>>>> True, Initially it was merged.But already existing drivers of which
>>>>> are of similar to this kind were done in this way.
>>>>> Please refer  /drivers/gpu/drm//exynos/exynos_hdmiphy.c
>>>>
>>>> Can you point to any discussions where it was decided to go with this approach?
>>> Sorry,what I meant is exynos_hdmiphy.c is already exist in the
>>> mainline with this approach.
>>>
>>> Initially it was merged on my local patches(Not upstreamed).But after
>>> referring to the
>>> exynos_hdmiphy.c driver and with lot of internal discussions ,it was
>>> decided to go with
>>
>> I don't have any idea about the internal discussions whatever you had. IMO
>> Exynos5250 sata phy driver should be modelled as an i2c client driver if you
>> don't have a good reason to do otherwise.
> In Exynos5250,some of the registers of SATA PHY controller are I/O
> mapped and some are accessible
> only through I2C controller.
> As the whole registers of SATA PHY controller cannot be accessible
> through I2C bus, it cannot be made as an i2c client driver.

Ah ok.. Makes sense. Thanks for clarifying.

Cheers
Kishon

>>
>> Thanks
>> Kishon
>>
>>> the already existing approach.
>>>
>>>>
>>>> Thanks
>>>> Kishon
>>