Re: [RFC PATCH] SDHCI: S3C: Add support for retrieving memory and irq resource information from device tree.
From: Grant Likely <hidden>
Date: 2011-01-31 16:41:21
On Mon, Jan 31, 2011 at 9:28 AM, [off-list ref] wrote:
quoted hunk
From: Thomas Abraham <redacted> Add support for retrieving memory and irq resource information from device tree for Samsung's SDHCI controller driver. Signed-off-by: Thomas Abraham <redacted> --- The modification will be made more generic to support both DT and non-DT versions of the driver without the #ifdef's. For now, this patch is for review and to understand if the approach adopted to obtain resource information from the device tree is appropriate. drivers/mmc/host/sdhci-s3c.c | 32 ++++++++++++++++++++++++++++++++ 1 files changed, 32 insertions(+), 0 deletions(-)diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c index 1720358..f536061 100644 --- a/drivers/mmc/host/sdhci-s3c.c +++ b/drivers/mmc/host/sdhci-s3c.c@@ -19,6 +19,9 @@#include <linux/clk.h> #include <linux/io.h> #include <linux/gpio.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/of_address.h> #include <linux/mmc/host.h>@@ -348,23 +351,52 @@ static int __devinit sdhci_s3c_probe(struct platform_device *pdev)struct sdhci_s3c *sc; struct resource *res; int ret, irq, ptr, clks; + struct device_node *np = NULL; +#ifdef CONFIG_OF + struct resource iores; +#endif if (!pdata) { dev_err(dev, "no device data specified\n"); return -ENOENT; } +#ifdef CONFIG_OF + for_each_compatible_node(np, NULL, "samsung,sdhci-s3c") { + const u32 *id = of_get_property(np, "cell-index", NULL); + if (be32_to_cpu(*id) == pdev->id) + break; + } + + if (!np) { + dev_err(dev, "no matching device node specified in device tree\n"); + return -ENOENT; + }
I think I've got a better solution to this which I'll be posting today. I've got code that allows the dt support code to 'snoop' platform bus registrations and set the of_node pointer for matching nodes. Then all the normal platform_bus support will work just fine. Doing it this way prevents building a kernel that supports both dt and non-dt booting. Also, relying on cell-index is generally considered a bad idea. When using the dt, let the kernel do the device enumeration instead of specifying it explicitly with cell-index.
+#endif + +#ifndef CONFIG_OF irq = platform_get_irq(pdev, 0); +#else + irq = of_irq_to_resource(np, 0, NULL); +#endif
When using the dt, platform_get_irq() should still work correctly. This shouldn't be necessary.
if (irq < 0) {
dev_err(dev, "no irq specified\n");
return irq;
}
+#ifndef CONFIG_OF
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(dev, "no memory specified\n");
return -ENOENT;
}
+#else
+ if (of_address_to_resource(np, 0, &iores)) {
+ dev_err(dev, "no memory specified in device tree\n");
+ return -ENOENT;
+ }
+ res = &iores;
+#endifDitto
host = sdhci_alloc_host(dev, sizeof(struct sdhci_s3c));
if (IS_ERR(host)) {
--
1.6.6.rc2
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