Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20220703170039.2058202-1-LinoSanfilippo@gmx.de> <20220703170039.2058202-6-LinoSanfilippo@gmx.de>
In-Reply-To: <20220703170039.2058202-6-LinoSanfilippo@gmx.de>
From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Sun, 3 Jul 2022 20:36:20 +0200
Message-ID: <CAHp75VfTQmzfVbxbVKWyWnJZERfPs5v=SmjexY0d+CPYXT7xgg@mail.gmail.com>
Subject: Re: [PATCH v2 5/9] dt_bindings: rs485: Correct delay values
To:     Lino Sanfilippo <LinoSanfilippo@gmx.de>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jirislaby@kernel.org>,
        =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Vladimir Zapolskiy <vz@mleia.com>,
        linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
        devicetree <devicetree@vger.kernel.org>,
        "open list:SERIAL DRIVERS" <linux-serial@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Lukas Wunner <lukas@wunner.de>, p.rosenberger@kunbus.com,
        Lino Sanfilippo <l.sanfilippo@kunbus.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Sun, Jul 3, 2022 at 7:02 PM Lino Sanfilippo <LinoSanfilippo@gmx.de> wrote:
>
> From: Lino Sanfilippo <l.sanfilippo@kunbus.com>
>
> Currently the documentation claims that a maximum of 1000 msecs is allowed
> for RTS delays. However nothing actually checks the values read from device
> tree/ACPI and so it is possible to set much higher values.
>
> There is already a maximum of 100 ms enforced for RTS delays that are set
> via the uart TIOCSRS485 ioctl. To be consistent with that use the same
> limit for DT/ACPI values.
>
> Although this change is visible to userspace the risk of breaking anything
> when reducing the max delays from 1000 to 100 ms should be very low, since
> 100 ms is already a very high maximum for delays that are usually rather in
> the usecs range.

Yeah, something similar is what you need to add to the previous patch IIUC.

-- 
With Best Regards,
Andy Shevchenko