From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Lubomir Rintel <lkundrak@v3.sk>
Cc: Mark Brown <broonie@kernel.org>,
Geert Uytterhoeven <geert+renesas@glider.be>,
quozl@laptop.org, Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Eric Miao <eric.y.miao@gmail.com>,
Haojian Zhuang <haojian.zhuang@gmail.com>,
Daniel Mack <daniel@zonque.org>,
Robert Jarzmik <robert.jarzmik@free.fr>,
linux-spi <linux-spi@vger.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 10/11] spi: pxa2xx: Add ready signal
Date: Thu, 11 Oct 2018 09:28:39 +0200 [thread overview]
Message-ID: <CAMuHMdXmsw3jjp8wFuuK_Vz8kwCP4=L59sc4kZafXzrb=hKv7g@mail.gmail.com> (raw)
In-Reply-To: <20181010170936.316862-11-lkundrak@v3.sk>
Hi Lubomir,
On Wed, Oct 10, 2018 at 7:10 PM Lubomir Rintel <lkundrak@v3.sk> wrote:
> Strobe a GPIO line when the slave TX FIFO is filled. This is how the
> Embedded Controller on an OLPC XO-1.75 machine, that happens to be a SPI
> master, learns that it can initiate a transaction.
>
> Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Thanks for your patch!
I'm repeating my comments on the RFC below:
> --- a/drivers/spi/spi-pxa2xx.c
> +++ b/drivers/spi/spi-pxa2xx.c
> @@ -1079,6 +1079,9 @@ static int pxa2xx_spi_transfer_one(struct spi_controller *master,
> if (spi_controller_is_slave(master)) {
> while (drv_data->write(drv_data))
> ;
> + gpiod_set_value(drv_data->gpiod_ready, 1);
> + udelay(1);
> + gpiod_set_value(drv_data->gpiod_ready, 0);
While gpiod_set_value() handles the case of no GPIO fine, I think it's
better to explicitly check for that, so you can avoid spinning for 1 µs if
the GPIO is not present.
> }
>
> /*
> @@ -1784,6 +1787,15 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
> }
> }
>
> + if (platform_info->is_slave) {
> + drv_data->gpiod_ready = devm_gpiod_get_optional(dev,
> + "ready", GPIOD_OUT_LOW);
> + if (IS_ERR(drv_data->gpiod_ready)) {
> + status = (int)PTR_ERR(drv_data->gpiod_ready);
The cast to int is not needed.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2018-10-11 7:28 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-10 17:09 [PATCH 0/11] spi: pxa2xx: add DT and slave mode support Lubomir Rintel
2018-10-10 17:09 ` [PATCH v2 01/11] dt-bindings: spi/spi-pxa2xx: add PXA2xx SSP SPI Controller Lubomir Rintel
2018-10-11 14:27 ` Mark Brown
2018-10-11 17:59 ` Lubomir Rintel
2018-10-12 17:00 ` Mark Brown
2018-10-17 19:32 ` Rob Herring
2018-11-04 12:00 ` Pavel Machek
2018-10-10 17:09 ` [PATCH v2 02/11] PCI: Provide pci_match_id() with CONFIG_PCI=n Lubomir Rintel
2018-11-04 12:02 ` Pavel Machek
2018-10-10 17:09 ` [PATCH 03/11] spi: pxa2xx: Use an enum for type Lubomir Rintel
2018-11-04 12:03 ` Pavel Machek
2018-10-10 17:09 ` [PATCH 04/11] spi: pxa2xx: Add devicetree support Lubomir Rintel
2018-11-04 12:04 ` Pavel Machek
2018-10-10 17:09 ` [PATCH 05/11] DT: marvell,mmp2: Add SSP1 and SSP3 Lubomir Rintel
2018-10-29 5:35 ` James Cameron
2018-11-04 12:06 ` Pavel Machek
2018-10-10 17:09 ` [PATCH 06/11] dt-bindings: spi/spi-pxa2xx: Add spi-slave property Lubomir Rintel
2018-10-17 19:33 ` Rob Herring
2018-11-04 12:07 ` Pavel Machek
2018-10-10 17:09 ` [PATCH 07/11] spi: Deal with slaves that return from transfer_one() unfinished Lubomir Rintel
2018-10-11 7:23 ` Geert Uytterhoeven
2018-11-04 12:09 ` Pavel Machek
2018-10-10 17:09 ` [PATCH 08/11] spi: pxa2xx: Add slave mode support Lubomir Rintel
2018-11-04 12:12 ` Pavel Machek
2018-10-10 17:09 ` [PATCH 09/11] dt-bindings: spi/spi-pxa2xx: Add ready GPIO signal Lubomir Rintel
2018-10-11 7:26 ` Geert Uytterhoeven
2018-11-04 12:13 ` Pavel Machek
2018-10-10 17:09 ` [PATCH 10/11] spi: pxa2xx: Add ready signal Lubomir Rintel
2018-10-11 7:28 ` Geert Uytterhoeven [this message]
2018-10-11 16:13 ` Lubomir Rintel
2018-11-04 12:16 ` Pavel Machek
2018-10-10 17:09 ` [PATCH 11/11] spi: pxa2xx: Deal with the leftover garbage in TXFIFO Lubomir Rintel
2018-11-04 12:19 ` Pavel Machek
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