From: Andrew Jeffery <andrew@codeconstruct.com.au>
To: Billy Tsai <billy_tsai@aspeedtech.com>,
linus.walleij@linaro.org, brgl@bgdev.pl, robh@kernel.org,
krzk+dt@kernel.org, conor+dt@kernel.org, joel@jms.id.au,
linux-gpio@vger.kernel.org, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org,
BMC-SW@aspeedtech.com, Peter.Yin@quantatw.com
Subject: Re: [PATCH v3 6/6] gpio: aspeed: Add the flush write to ensure the write complete.
Date: Mon, 16 Sep 2024 12:33:10 +0930 [thread overview]
Message-ID: <7433f7d95a0a51eb54ea0b1c9db102adb029f946.camel@codeconstruct.com.au> (raw)
In-Reply-To: <20240913074325.239390-7-billy_tsai@aspeedtech.com>
On Fri, 2024-09-13 at 15:43 +0800, Billy Tsai wrote:
> Performing a dummy read ensures that the register write operation is fully
> completed, mitigating any potential bus delays that could otherwise impact
> the frequency of bitbang usage. E.g., if the JTAG application uses GPIO to
> control the JTAG pins (TCK, TMS, TDI, TDO, and TRST), and the application
> sets the TCK clock to 1 MHz, the GPIO’s high/low transitions will rely on
> a delay function to ensure the clock frequency does not exceed 1 MHz.
> However, this can lead to rapid toggling of the GPIO because the write
> operation is POSTed and does not wait for a bus acknowledgment.
>
> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
... are you aware of any other driver concerns of a similar nature wrt
the architecture of the SoCs?
next prev parent reply other threads:[~2024-09-16 3:03 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-13 7:43 [PATCH v3 0/6] Add Aspeed G7 gpio support Billy Tsai
2024-09-13 7:43 ` [PATCH v3 1/6] dt-bindings: gpio: aspeed,ast2400-gpio: Support ast2700 Billy Tsai
2024-09-13 18:22 ` Conor Dooley
2024-09-13 7:43 ` [PATCH v3 2/6] gpio: aspeed: Remove the name for bank array Billy Tsai
2024-09-16 1:51 ` Andrew Jeffery
2024-09-13 7:43 ` [PATCH v3 3/6] gpio: aspeed: Create llops to handle hardware access Billy Tsai
2024-09-16 2:43 ` Andrew Jeffery
2024-09-16 3:00 ` Andrew Jeffery
2024-09-19 6:12 ` Billy Tsai
2024-09-13 7:43 ` [PATCH v3 4/6] gpio: aspeed: Support G7 Aspeed gpio controller Billy Tsai
2024-09-13 7:43 ` [PATCH v3 5/6] gpio: aspeed: Change the macro to support deferred probe Billy Tsai
2024-09-14 8:44 ` kernel test robot
2024-09-14 15:33 ` kernel test robot
2024-09-13 7:43 ` [PATCH v3 6/6] gpio: aspeed: Add the flush write to ensure the write complete Billy Tsai
2024-09-16 3:03 ` Andrew Jeffery [this message]
2024-09-19 6:07 ` Billy Tsai
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