From: Serge Semin <Sergey.Semin@baikalelectronics.ru>
To: Mark Brown <broonie@kernel.org>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>,
Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Lars Povlsen <lars.povlsen@microchip.com>,
"wuxu . wu" <wuxu.wu@huawei.com>, Feng Tang <feng.tang@intel.com>,
Rob Herring <robh+dt@kernel.org>, <linux-spi@vger.kernel.org>,
<devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 02/30] spi: dw: Use ternary op to init set_cs callback
Date: Wed, 30 Sep 2020 00:55:53 +0300 [thread overview]
Message-ID: <20200929215553.xgst2v5ssweymlpw@mobilestation> (raw)
In-Reply-To: <20200929131153.GD4799@sirena.org.uk>
On Tue, Sep 29, 2020 at 02:11:53PM +0100, Mark Brown wrote:
> On Sun, Sep 20, 2020 at 02:28:46PM +0300, Serge Semin wrote:
> > Simplify the dw_spi_add_host() method a bit by replacing the set_cs
> > callback overwrite procedure with direct setting the callback if a custom
> > version of one is specified.
>
> > - master->set_cs = dw_spi_set_cs;
> > + master->set_cs = dws->set_cs ?: dw_spi_set_cs;
>
> > - if (dws->set_cs)
> > - master->set_cs = dws->set_cs;
>
> This doesn't look like a win for legibility or comprehensibility.
Assigning a default value and redefining it way later doesn't look legible
either, because in that case you'd need to keep in mind, that some callback has
already been set. Moreover it does one redundant assignment. That's why I
decided to implement the setting up by means of the ternary op.
If you don't like the ternary op, then we could use an explicit if-else
statement here. But I'd insist on implementing the assignment in a one
place of the function instead of having it partly perform here and partly there.
Like this:
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -477,7 +477,10 @@ int dw_spi_add_host(struct device *dev, struct dw_spi *dws)
master->num_chipselect = dws->num_cs;
master->setup = dw_spi_setup;
master->cleanup = dw_spi_cleanup;
- master->set_cs = dw_spi_set_cs;
+ if (dws->set_cs)
+ master->set_cs = dws->set_cs;
+ else
+ master->set_cs = dw_spi_set_cs;
master->transfer_one = dw_spi_transfer_one;
master->handle_err = dw_spi_handle_err;
master->max_speed_hz = dws->max_freq;
Personally I prefer the ternary op in such situations. The operator provides an
elegant small well known solution for the default-assignments. I don't see it
as non-legible or incomprehensible. (I don't really understand why you and
Andy don't like the operator that much =))
-Sergey
next prev parent reply other threads:[~2020-09-29 21:56 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-20 11:28 [PATCH 00/30] spi: dw: Add full Baikal-T1 SPI Controllers support Serge Semin
2020-09-20 11:28 ` [PATCH 01/30] spi: dw: Discard IRQ threshold macro Serge Semin
2020-09-20 11:28 ` [PATCH 02/30] spi: dw: Use ternary op to init set_cs callback Serge Semin
2020-09-29 13:11 ` Mark Brown
2020-09-29 21:55 ` Serge Semin [this message]
2020-09-30 14:57 ` Serge Semin
2020-09-30 15:01 ` Mark Brown
2020-09-30 15:07 ` Serge Semin
2020-09-20 11:28 ` [PATCH 03/30] spi: dw: Initialize n_bytes before the memory barrier Serge Semin
2020-09-29 13:12 ` Mark Brown
2020-09-29 22:05 ` Serge Semin
2020-09-20 11:28 ` [PATCH 04/30] Revert: spi: spi-dw: Add lock protect dw_spi rx/tx to prevent concurrent calls Serge Semin
2020-09-29 13:28 ` Mark Brown
2020-09-29 22:08 ` Serge Semin
2020-09-20 11:28 ` [PATCH 05/30] spi: dw: Clear IRQ status on DW SPI controller reset Serge Semin
2020-09-20 11:28 ` [PATCH 06/30] spi: dw: Disable all IRQs when controller is unused Serge Semin
2020-09-20 11:28 ` [PATCH 07/30] spi: dw: Use relaxed IO-methods to access FIFOs Serge Semin
2020-09-20 11:28 ` [PATCH 08/30] spi: dw: Discard DW SSI chip type storages Serge Semin
2020-09-20 11:28 ` [PATCH 09/30] spi: dw: Convert CS-override to DW SPI capabilities Serge Semin
2020-09-20 11:28 ` [PATCH 10/30] spi: dw: Add KeemBay Master capability Serge Semin
2020-09-20 11:28 ` [PATCH 11/30] spi: dw: Add DWC SSI capability Serge Semin
2020-09-29 13:52 ` Mark Brown
2020-09-29 22:17 ` Serge Semin
2020-09-30 15:03 ` Serge Semin
2020-09-30 15:41 ` Mark Brown
2020-09-30 15:53 ` Serge Semin
2020-09-20 11:28 ` [PATCH 12/30] spi: dw: Detach SPI device specific CR0 config method Serge Semin
2020-09-20 11:28 ` [PATCH 13/30] spi: dw: Update SPI bus speed in a config function Serge Semin
2020-09-20 11:28 ` [PATCH 14/30] spi: dw: Simplify the SPI bus speed config procedure Serge Semin
2020-09-20 11:28 ` [PATCH 15/30] spi: dw: Update Rx sample delay in the config function Serge Semin
2020-09-20 11:29 ` [PATCH 16/30] spi: dw: Add DW SPI controller config structure Serge Semin
2020-09-20 11:29 ` [PATCH 17/30] spi: dw: Refactor data IO procedure Serge Semin
2020-09-20 11:29 ` [PATCH 18/30] spi: dw: Refactor IRQ-based SPI transfer procedure Serge Semin
2020-09-20 11:29 ` [PATCH 19/30] spi: dw: Perform IRQ setup in a dedicated function Serge Semin
2020-09-20 11:29 ` [PATCH 20/30] spi: dw: Unmask IRQs after enabling the chip Serge Semin
2020-09-20 11:29 ` [PATCH 21/30] spi: dw: Discard chip enabling on DMA setup error Serge Semin
2020-09-20 11:29 ` [PATCH 22/30] spi: dw: De-assert chip-select on reset Serge Semin
2020-09-20 11:29 ` [PATCH 23/30] spi: dw: Explicitly de-assert CS on SPI transfer completion Serge Semin
2020-09-20 11:29 ` [PATCH 24/30] spi: dw: Move num-of retries parameter to the header file Serge Semin
2020-09-20 11:29 ` [PATCH 25/30] spi: dw: Add generic DW SSI status-check method Serge Semin
2020-09-20 11:29 ` [PATCH 26/30] spi: dw: Add memory operations support Serge Semin
2020-09-20 11:29 ` [PATCH 27/30] spi: dw: Introduce max mem-ops SPI bus frequency setting Serge Semin
2020-09-20 11:29 ` [PATCH 28/30] spi: dw: Add poll-based SPI transfers support Serge Semin
2020-09-20 11:29 ` [PATCH 29/30] dt-bindings: spi: dw: Add Baikal-T1 SPI Controllers Serge Semin
2020-09-29 16:58 ` Rob Herring
2020-09-20 11:41 ` [PATCH 30/30] spi: dw: Add Baikal-T1 SPI Controller glue driver Serge Semin
2020-09-29 14:43 ` [PATCH 00/30] spi: dw: Add full Baikal-T1 SPI Controllers support Mark Brown
2020-09-29 22:43 ` Serge Semin
2020-09-30 11:04 ` Mark Brown
2020-09-30 13:11 ` Serge Semin
2020-09-30 14:43 ` Mark Brown
2020-09-29 16:23 ` Mark Brown
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