On 1/26/2016 7:38 AM, Andy Shevchenko wrote:

On Mon, Jan 25, 2016 at 11:29 PM, Sinan Kaya [off-list ref] wrote:

Few comments below.

quoted

Generic Event Device described in ACPI 6.1 allows platforms to handle
platform interrupts in ACPI ASL statements. It borrows constructs like
_EVT from GPIO events.

Can it share code with gpiolib-acpi.c ? I see some duplication.

The interrupt registration mechanism could be made common but they have their own
data structure types. 

Can Rafael think of any higher level API like acpi_dev_resource_interrupt below?

quoted

All interrupts are listed in _CRS and the handler
is written in _EVT method. Here is an example.

quoted

Device (GED0)
{

        Name (_HID, "ACPI0013")
        Name (_UID, 0)
        Name(_CRS, ResourceTemplate ()
        {
                Interrupt(ResourceConsumer, Edge, ActiveHigh, Shared, , , )
                 {123}
        })

        Method (_EVT, 1) {
                if (Lequal(123, Arg0))
                {
                }
        }
}

Wake capability has not been implemented yet.

Signed-off-by: Sinan Kaya <redacted>
---
 drivers/acpi/Makefile |   1 +
 drivers/acpi/evged.c  | 162 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 163 insertions(+)
 create mode 100644 drivers/acpi/evged.c

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index b5e7cd8..4dbb732 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile

@@ -46,6 +46,7 @@ acpi-y                                += acpi_pnp.o
 acpi-y                         += int340x_thermal.o
 acpi-y                         += power.o
 acpi-y                         += event.o
+acpi-$(CONFIG_ACPI_REDUCED_HARDWARE_ONLY) += evged.o
 acpi-y                         += sysfs.o
 acpi-y                         += property.o
 acpi-$(CONFIG_X86)             += acpi_cmos_rtc.o

diff --git a/drivers/acpi/evged.c b/drivers/acpi/evged.c
new file mode 100644
index 0000000..a904676
--- /dev/null
+++ b/drivers/acpi/evged.c

@@ -0,0 +1,162 @@
+/*
+ * Generic Event Device for ACPI.
+ *
+ * Copyright (c) 2016, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Generic Event Device allows platforms to handle
+ * interrupts in ACPI ASL statements. It follows very similar
+ * _EVT method approach from GPIO events.
+ * All interrupts are listed in _CRS and the handler
+ * is written in _EVT method. Here is an example.

Can it be wider on screen?

sure

quoted

+
+       event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL);
+       if (!event)
+               return AE_ERROR;
+
+       event->gsi = gsi;
+       event->dev = dev;
+       event->irq = irq;
+       event->handle = evt_handle;
+
+       if (r.flags & IORESOURCE_IRQ_SHAREABLE)
+               irqflags |= IRQF_SHARED;
+
+       if (devm_request_threaded_irq(dev, irq, NULL, acpi_ged_irq_handler,
+                                     irqflags, "ACPI:Ged", event)) {
+               dev_err(dev, "failed to setup event handler for irq %u\n", irq);
+               return AE_ERROR;
+       }

The above part is clearly belongs to ged_probe().

It depends. The implementation needs to find all the interrupt entries in _CRS. That's why, 
the interrupt registration is done inside the ACPI callback.

I originally tried using the platform_get_irq() method rather than walking the ACPI resources. 
Any resource listed in _CRS is accessible via standard platform API. However, I couldn't obtain 
the shareability and other edge/level attributes through the standard APIs. Most drivers I have 
seen hardcode this information when calling devm_request_threaded_irq function.

Here, the type of interrupt is declared in the ACPI and the registration is done based on passed
attributes.

quoted

+
+       return AE_OK;
+}
+
+static int ged_probe(struct platform_device *pdev)
+{
+       acpi_status acpi_ret;
+
+       acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
+                                      acpi_ged_request_interrupt, &pdev->dev);
+       if (ACPI_FAILURE(acpi_ret)) {
+               dev_err(&pdev->dev, "unable to parse the _CRS record\n");
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+static const struct acpi_device_id ged_acpi_ids[] = {
+       {"ACPI0013"},
+       {},
+};
+
+static struct platform_driver ged_driver = {
+       .probe = ged_probe,
+       .driver = {
+               .name = MODULE_NAME,

quoted

+               .owner = THIS_MODULE,

Do you need this one?

I'll get rid of it.

quoted

+               .acpi_match_table = ACPI_PTR(ged_acpi_ids),
+       },
+};
+
+static int __init ged_init(void)
+{
+       return platform_driver_register(&ged_driver);
+}
+

quoted

+subsys_initcall(ged_init);

Any specific reason to have on that level?

changed to module_platform_driver(ged_driver); 

-- 
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project