linux-kernel - Re: [PATCH v4 0/4] Simplify PCIe hotplug indicator control

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Date:   Fri, 6 Sep 2019 00:16:06 +0300
From:   Denis Efremov <efremov@...ux.com>
To:     Bjorn Helgaas <helgaas@...nel.org>
Cc:     Lukas Wunner <lukas@...ner.de>, linux-pci@...r.kernel.org,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        Oliver O'Halloran <oohall@...il.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 0/4] Simplify PCIe hotplug indicator control



On 06.09.2019 00:01, Bjorn Helgaas wrote:
> On Tue, Sep 03, 2019 at 02:10:17PM +0300, Denis Efremov wrote:
>> PCIe defines two optional hotplug indicators: a Power indicator and an
>> Attention indicator. Both are controlled by the same register, and each
>> can be on, off or blinking. The current interfaces
>> (pciehp_green_led_{on,off,blink}() and pciehp_set_attention_status()) are
>> non-uniform and require two register writes in many cases where we could
>> do one.
>>
>> This patchset introduces the new function pciehp_set_indicators(). It
>> allows one to set two indicators with a single register write. All
>> calls to previous interfaces (pciehp_green_led_* and
>> pciehp_set_attention_status()) are replaced with a new one. Thus,
>> the amount of duplicated code for setting indicators is reduced.
>>
>> Changes in v4:
>>   - Changed the inputs validation in pciehp_set_indicators()
>>   - Moved PCI_EXP_SLTCTL_ATTN_IND_NONE, PCI_EXP_SLTCTL_PWR_IND_NONE
>>     to drivers/pci/hotplug/pciehp.h and set to -1 for not interfering
>>     with reserved values in the PCIe Base spec
>>   - Added set_power_indicator define
>>
>> Changes in v3:
>>   - Changed pciehp_set_indicators() to work with existing
>>     PCI_EXP_SLTCTL_* macros
>>   - Reworked the inputs validation in pciehp_set_indicators()
>>   - Removed pciehp_set_attention_status() and pciehp_green_led_*()
>>     completely
>>
>> Denis Efremov (4):
>>   PCI: pciehp: Add pciehp_set_indicators() to jointly set LED indicators
>>   PCI: pciehp: Switch LED indicators with a single write
>>   PCI: pciehp: Remove pciehp_set_attention_status()
>>   PCI: pciehp: Remove pciehp_green_led_{on,off,blink}()
>>
>>  drivers/pci/hotplug/pciehp.h      | 12 ++++--
>>  drivers/pci/hotplug/pciehp_core.c |  7 ++-
>>  drivers/pci/hotplug/pciehp_ctrl.c | 26 +++++------
>>  drivers/pci/hotplug/pciehp_hpc.c  | 72 +++++++------------------------
>>  include/uapi/linux/pci_regs.h     |  1 +
>>  5 files changed, 45 insertions(+), 73 deletions(-)
> 
> Thanks, Denis, I applied these to pci/pciehp for v5.4.  I think this
> is a great improvement.
> 
> I tweaked a few things:
> 
>   - Updated comments to refer to "Power" intead of "green",
>     "Attention" instead of "amber", and "Indicator" instead of "LED".
> 
>   - Replaced PCI_EXP_SLTCTL_ATTN_IND_NONE and
>     PCI_EXP_SLTCTL_PWR_IND_NONE with INDICATOR_NOOP because I didn't
>     want them to look like definitions from the spec.
> 
>   - Dropped set_power_indicator().  It does make things locally easier
>     to read, but I think the overall benefit of having fewer
>     interfaces outweighs that.
> 
> The interdiff from your v4 is below.  Let me know if I broke anything.

Thank you for the improvements. Looks good to me.

Regards,
Denis