Re: [PATCH 1/8] serial: core: only get RS485 termination gpio if supported
From: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Date: 2022-06-23 02:00:08
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linux-devicetree, linux-serial, lkml
Hi, On 22.06.22 at 19:04, Andy Shevchenko wrote:
On Wed, Jun 22, 2022 at 05:46:52PM +0200, Lino Sanfilippo wrote:quoted
From: Lino Sanfilippo <redacted> In uart_get_rs485_mode() only try to get a termination GPIO if RS485 bus termination is supported by the driver.I'm not sure I got the usefulness of this change. We request GPIO line as optional, so if one is defined it in the DT/ACPI, then they probably want to (opportunistically) have it> With your change it's possible to have a DTS where GPIO line defined in a broken way and user won't ever know about it, if they are using platforms without termination support.
This behavior is not introduced with this patch, also in the current code the driver wont inform the user if it does not make use erroneous defined termination GPIO. This patch at least prevents the driver from allocating and holding a GPIO descriptor across the drivers lifetime that will never be used. Furthermore it simplifies the code in patch 2 when we want to set the GPIO, since we can skip the check whether or not the termination GPIO is supported by the driver. Regards, Lino _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel