Thread (37 messages) 37 messages, 11 authors, 2014-09-15

[RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

From: arnd@arndb.de (Arnd Bergmann)
Date: 2014-09-01 17:12:35
Also in: linux-acpi, lkml

On Monday 01 September 2014 18:04:47 Catalin Marinas wrote:
On Mon, Sep 01, 2014 at 04:06:00PM +0100, Hanjun Guo wrote:
quoted
+#ifdef CONFIG_ACPI
+/* Configure some sensible defaults for ACPI mode */
+static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
+                                 acpi_handle *ahandle)
+{
+     if (!ahandle)
+             return -ENOSYS;
+
+     config->phy_interface = PHY_INTERFACE_MODE_MII;
+
+     config->flags |= SMSC911X_USE_32BIT;
+
+     config->irq_polarity = SMSC911X_IRQ_POLARITY_ACTIVE_HIGH;
+
+     config->irq_type = SMSC911X_IRQ_TYPE_PUSH_PULL;
+
+     return 0;
+}
+#else
I don't like this and it shows issues we have with ACPI on certain ARM
platforms. You hard-code these values to match the Juno platform. What
if we get another SoC which has different configuration here? For DT, we
have the smsc911x_probe_config_dt() which reads the relevant information
from DT. I think this kind of configuration would be more suitable as
_DSD properties and sharing the similar names with DT (but we go back to
the question about who's in charge of the _DSD properties).
Good point, I totally missed that.

There is of course the possibility to set those values based on the
acpi_device_id, but that is exactly the part that _DSD is trying to
avoid.
quoted
 static int smsc911x_drv_probe(struct platform_device *pdev)
 {
      struct device_node *np = pdev->dev.of_node;
+     acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);
      struct net_device *dev;
      struct smsc911x_data *pdata;
      struct smsc911x_platform_config *config = dev_get_platdata(&pdev->dev);
@@ -2436,6 +2464,9 @@ static int smsc911x_drv_probe(struct platform_device *pdev)
      }
 
      retval = smsc911x_probe_config_dt(&pdata->config, np);
+     if (retval)
+             retval = smsc911x_probe_config_acpi(&pdata->config, ahandle);
+
In most of the ACPI patches so far we check for ACPI first with DT as a
fall-back if ACPI is not enabled. This changes here.
Does this really make a difference?
I would prefer
something which probes only ACPI if the ACPI is enabled (run-time, not
config) otherwise DT only. E.g.
(example missing?)

I think we should have the equivalent of of_have_populated_dt(), to
check whether acpi is being used to boot, and have that new function
be hardcoded to zero in case of !IS_ENABLED(CONFIG_ACPI).

	Arnd
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