platform/chrome: Add a new interrupt path for cros_ec_lpc
authorEnrico Granata <egranata@chromium.org>
Tue, 9 Oct 2018 17:56:46 +0000 (10:56 -0700)
committerBenson Leung <bleung@chromium.org>
Wed, 10 Oct 2018 04:44:44 +0000 (21:44 -0700)
This commit allows cros_ec_lpc to register a direct IRQ instead of relying
on the ACPI notification chain to receive MKBP events.

This change is done in the interest of allowing reduced jitter in the
communication path between the CrOS EC and the host for receiving sensor
data.

Signed-off-by: Enrico Granata <egranata@chromium.org>
Signed-off-by: Benson Leung <bleung@chromium.org>
drivers/platform/chrome/cros_ec_lpc.c

index 7ec8789bf1618b248181dacd04645d51e4802a5a..e1b75775cd4a12867b1b3b4566140605564c7085 100644 (file)
@@ -25,6 +25,7 @@
 #include <linux/dmi.h>
 #include <linux/delay.h>
 #include <linux/io.h>
+#include <linux/interrupt.h>
 #include <linux/mfd/cros_ec.h>
 #include <linux/mfd/cros_ec_commands.h>
 #include <linux/module.h>
@@ -249,7 +250,7 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
        acpi_status status;
        struct cros_ec_device *ec_dev;
        u8 buf[2];
-       int ret;
+       int irq, ret;
 
        if (!devm_request_region(dev, EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE,
                                 dev_name(dev))) {
@@ -288,6 +289,18 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
                           sizeof(struct ec_response_get_protocol_info);
        ec_dev->dout_size = sizeof(struct ec_host_request);
 
+       /*
+        * Some boards do not have an IRQ allotted for cros_ec_lpc,
+        * which makes ENXIO an expected (and safe) scenario.
+        */
+       irq = platform_get_irq(pdev, 0);
+       if (irq > 0)
+               ec_dev->irq = irq;
+       else if (irq != -ENXIO) {
+               dev_err(dev, "couldn't retrieve IRQ number (%d)\n", irq);
+               return irq;
+       }
+
        ret = cros_ec_register(ec_dev);
        if (ret) {
                dev_err(dev, "couldn't register ec_dev (%d)\n", ret);