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Subject: Re: [PATCH 1/4] pmbus: associate PMBUS_SKIP_STATUS_CHECK with
 driver_data
To:     Xiaoting Liu <xiaoting.liu@hxt-semitech.com>, jdelvare@suse.com
Cc:     openbmc@lists.ozlabs.org, linux-hwmon@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Shunyong Yang <shunyong.yang@hxt-semitech.com>
References: <cover.1546591275.git.xiaoting.liu@hxt-semitech.com>
 <680b4d5659971cc4f6e1a6878837c2ce49962a7c.1546591275.git.xiaoting.liu@hxt-semitech.com>
From:   Guenter Roeck <linux@roeck-us.net>
Message-ID: <b9548ce0-97d2-a3d4-d578-015fc5419967@roeck-us.net>
Date:   Fri, 4 Jan 2019 06:54:07 -0800
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On 1/4/19 12:55 AM, Xiaoting Liu wrote:
> Current code compares device name with name in i2c_device_id to decide
> whether PMBUS_SKIP_STATUS_CHECK should be set in pmbus_platform_data,
> which makes adding new devices with PMBUS_SKIP_STATUS_CHECK should also
> modify code in pmbus_probe().
> 
> This patch adds pmbus_device_info to save pages and flags. Its pointer
> is put in driver_data of i2c_device_id, which makes adding new device
> more straightforward.
> 

Good idea, but I don't see at this time where the patch is needed.
Maybe in patch 3/4 which is missing from the series ?

> Signed-off-by: Shunyong Yang <shunyong.yang@hxt-semitech.com>
> Signed-off-by: Xiaoting Liu <xiaoting.liu@hxt-semitech.com>
> ---
>   drivers/hwmon/pmbus/pmbus.c | 54 +++++++++++++++++++++++++++------------------
>   include/linux/pmbus.h       |  5 +++++
>   2 files changed, 37 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus.c b/drivers/hwmon/pmbus/pmbus.c
> index 7688dab32f6e..aa4cf9636e99 100644
> --- a/drivers/hwmon/pmbus/pmbus.c
> +++ b/drivers/hwmon/pmbus/pmbus.c
> @@ -172,13 +172,15 @@ static int pmbus_probe(struct i2c_client *client,
>          struct pmbus_driver_info *info;
>          struct pmbus_platform_data *pdata = NULL;
>          struct device *dev = &client->dev;
> +       struct pmbus_device_info *device_info;
> 
>          info = devm_kzalloc(dev, sizeof(struct pmbus_driver_info), GFP_KERNEL);
>          if (!info)
>                  return -ENOMEM;
> 
> -       if (!strcmp(id->name, "dps460") || !strcmp(id->name, "dps800") ||
> -           !strcmp(id->name, "sgd009")) {
> +       device_info = (struct pmbus_device_info *)id->driver_data;
> +
> +       if (device_info->flags & PMBUS_SKIP_STATUS_CHECK) {
>                  pdata = devm_kzalloc(dev, sizeof(struct pmbus_platform_data),
>                                       GFP_KERNEL);
>                  if (!pdata)
> @@ -187,36 +189,44 @@ static int pmbus_probe(struct i2c_client *client,
>                  pdata->flags = PMBUS_SKIP_STATUS_CHECK;
>          }
> 
> -       info->pages = id->driver_data;
> +       info->pages = device_info->pages;
>          info->identify = pmbus_identify;
>          dev->platform_data = pdata;
> 
>          return pmbus_do_probe(client, id, info);
>   }
> 
> +static const struct pmbus_device_info default_pmbus_info = {1, 0};
> +static const struct pmbus_device_info dps460_pmbus_info = {
> +                               1, PMBUS_SKIP_STATUS_CHECK};
> +static const struct pmbus_device_info dps800_pmbus_info = {
> +                               1, PMBUS_SKIP_STATUS_CHECK};
> +static const struct pmbus_device_info sgd009_pmbus_info = {
> +                               1, PMBUS_SKIP_STATUS_CHECK};

Three structures with exactly the same content does not add value.
Please merge into one with a common name that reflects its use.

> +static const struct pmbus_device_info pmbus_info = {0, 0};

default_pmbus_info and pmbus_info are badly named and ordered.
The name should reflect that one sets one page and that the other
leaves the number of pages unset.

I would suggest three structures and names, such as

pmbus_info_one
pmbus_info_one_skip
pmbus_info_zero

though I am open to better names.

>   /*
>    * Use driver_data to set the number of pages supported by the chip.
>    */
>   static const struct i2c_device_id pmbus_id[] = {
> -       {"adp4000", 1},
> -       {"bmr453", 1},
> -       {"bmr454", 1},
> -       {"dps460", 1},
> -       {"dps800", 1},
> -       {"mdt040", 1},
> -       {"ncp4200", 1},
> -       {"ncp4208", 1},
> -       {"pdt003", 1},
> -       {"pdt006", 1},
> -       {"pdt012", 1},
> -       {"pmbus", 0},
> -       {"sgd009", 1},
> -       {"tps40400", 1},
> -       {"tps544b20", 1},
> -       {"tps544b25", 1},
> -       {"tps544c20", 1},
> -       {"tps544c25", 1},
> -       {"udt020", 1},
> +       {"adp4000", (kernel_ulong_t)&default_pmbus_info},
> +       {"bmr453", (kernel_ulong_t)&default_pmbus_info},
> +       {"bmr454", (kernel_ulong_t)&default_pmbus_info},
> +       {"dps460", (kernel_ulong_t)&dps460_pmbus_info},
> +       {"dps800", (kernel_ulong_t)&dps800_pmbus_info},
> +       {"mdt040", (kernel_ulong_t)&default_pmbus_info},
> +       {"ncp4200", (kernel_ulong_t)&default_pmbus_info},
> +       {"ncp4208", (kernel_ulong_t)&default_pmbus_info},
> +       {"pdt003", (kernel_ulong_t)&default_pmbus_info},
> +       {"pdt006", (kernel_ulong_t)&default_pmbus_info},
> +       {"pdt012", (kernel_ulong_t)&default_pmbus_info},
> +       {"pmbus", (kernel_ulong_t)&pmbus_info},
> +       {"sgd009", (kernel_ulong_t)&sgd009_pmbus_info},
> +       {"tps40400", (kernel_ulong_t)&default_pmbus_info},
> +       {"tps544b20", (kernel_ulong_t)&default_pmbus_info},
> +       {"tps544b25", (kernel_ulong_t)&default_pmbus_info},
> +       {"tps544c20", (kernel_ulong_t)&default_pmbus_info},
> +       {"tps544c25", (kernel_ulong_t)&default_pmbus_info},
> +       {"udt020", (kernel_ulong_t)&default_pmbus_info},
>          {}
>   };
> 
> diff --git a/include/linux/pmbus.h b/include/linux/pmbus.h
> index ee3c2aba2a8e..3c05edad7666 100644
> --- a/include/linux/pmbus.h
> +++ b/include/linux/pmbus.h
> @@ -46,4 +46,9 @@ struct pmbus_platform_data {
>          struct regulator_init_data *reg_init_data;
>   };
> 
> +struct pmbus_device_info {
> +       int pages;
> +       u32 flags;
> +};
> +

This should not be needed here. The structure can be declared locally
in pmbus.c (its use in patch 4/4 is wrong).

>   #endif /* _PMBUS_H_ */
> --
> 1.8.3.1
> 
> 
> 
> 
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