Hi Mark,
Many thanks for your review, I'm so sorry for late reply because The
Chinese
new year holiday. See my replies below.
Best Regards
Jiang
在 2016/2/5 19:09, Mark Brown 写道:
On Fri, Feb 05, 2016 at 03:11:20PM +0800, qiujiang wrote:
This patch added ACPI support for DesignWare SPI mmio driver. It
was based the corresponding DT driver and compatible for this two
way. This patch has been tested on Hisilicon D02 board. It relies
on the GPIO patchset.
Intel are heavy users of this driver on their systems which also use
ACPI. Have you discussed this binding with them? I've copied Andy and
Jarkko who've worked on the driver recently.
I'm going to ask Andy to get some ideas that how to use this spi-dw-mmio
driver by ACPI binding.
Please use subject lines matching the style for the subsystem. This
makes it easier for people to identify relevant patches.
Thanks for the reminder, I will fix it in the next version.
+ char propname[32];
That's a magic number, where did it come from and why is it a magic
nummber?
I'm sorry for here without any comments. This number define is come from
gpiolib.c. It means the max size of gpio property name. The reference code
located in line 1815 of gpiolib.c.
+ if (ACPI_COMPANION(&pdev->dev)) {
+ for (i = 0; i < dws->num_cs; i++) {
+ snprintf(propname, sizeof(propname), "cs%d", i);
+ gpiod = devm_gpiod_get(&pdev->dev,
+ propname, GPIOD_ASIS);
+ if (IS_ERR(gpiod)) {
+ dev_err(&pdev->dev, "Get gpio desc failed!\n");
+ return PTR_ERR(gpiod);
+ }
+ }
+ }
I'm not seeing anywhere where we store the GPIO in this loop. It is
therefore unclear to me how the chip select is going to work?
In DT binding, of_get_named_gpio and devm_gpio_request were used to
parse gpio
pins defined in DTs and then request these pins. Similarly, for ACPI,
devm_gpiod_get
can do that two operation in a single function. It is a unified
interface to ACPI and DT
binding.
If the gpiod is valid, the corresponding gpio pins has been requested.
We do not need
to save this gpiod any more.
which gpio pin was used is defined in spi_device, named cs_gpio, the
configuration to the
gpio pins will be done in the setup callback routine of each device.
What the spi master
should do is just request these pins to the gpio subsystem.
+static const struct acpi_device_id dw_spi_mmio_acpi_match[] = {
+ {"HISI0171", 0},
+ { }
+};
+MODULE_DEVICE_TABLE(acpi, dw_spi_mmio_acpi_match);
I really do wish ACPI had some more sensible system for allocating
device IDs so the tables were a little more legible. :(
This is really a question, I will do this feedback to ACPI maintainers.
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