Messages in this thread | | | From | Måns Rullgård <> | Subject | Re: Grafting old platform drivers onto a new DT kernel | Date | Mon, 09 Nov 2015 15:40:10 +0000 |
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Mason <slash.tmp@free.fr> writes:
> On 05/11/2015 16:42, Javier Martinez Canillas wrote: >> Hello, >> >> On Thu, Nov 5, 2015 at 12:15 PM, Andrew Lunn <andrew@lunn.ch> wrote: >>>> Since I don't have time to rewrite the drivers at the moment, I'm wondering >>>> if it's possible to "graft" old drivers (they're using the platform API, no >>>> trace of DT support) onto my small base? >>> >>> Platform drivers are still usable with DT systems. We used that fact >>> when converting platform based machines over to DT, one driver at a >>> time. Look in the git history for kirkwood devices. e.g. somewhere >>> around v3.7, arch/arm/mach-kirkwood. board-dt.c, and the various >>> board-*.c files, and the DT files in the usual place. >>> >> >> OMAP did the same and still some boards use platform data and manually >> register platform devices from board code. Take a look to >> arch/arm/mach-omap2/pdata-quirks.c to see how that is being done. > > Hello, > > I tried compiling an ancient SDHCI driver on a v4.2 system. It crashes > all over init because several host->ops functions are required, but the > old driver does not define them: > .reset > .set_clock > .set_bus_width > .set_uhs_signaling > > So I downgraded to an older v3.14 kernel, and that problem vanished. > But I am having a problem with the IRQ setup. > > # cat /proc/interrupts > CPU0 CPU1 > 18: 93 0 irq0 1 Level serial > 55: 2832 0 irq0 38 Level 26000.ethernet > 60: 0 0 irq0 43 Edge mmc0 > 211: 319 2603 GIC 29 Edge twd > > Ethernet is using IRQ 38, as specified in the DT. > mmc0 is supposed to use IRQ 60. > > I see that the mmc0 has the index 60, so I must have messed up between > the real irq (hwirq?) and the index Linux uses internally (virq?) > > static struct resource sdhci_resources[] = { > { > .start = TANGOX_SDIO0_BASE_ADDR, > .end = TANGOX_SDIO0_BASE_ADDR + 0x1ff, > .flags = IORESOURCE_MEM, > }, > { > .start = 60, /* SDHCI0 IRQ */ > .flags = IORESOURCE_IRQ, > }, > }; > > Both ethernet and sdhci driver call platform_get_irq(pdev, 0); > but the eth driver is DT, so calls of_irq_get() while sdhci is > legacy, so calls platform_get_resource() -- IIUC. > > How do I specify a "hwirq" instead of a "Linux index"? and where?
The simplest solution for you is probably to add a quick and dirty DT binding to the old driver. If it doesn't use any driver-specific platform data struct, you only need to set .of_match_table in the struct platform_driver. If there is a platform data struct, you'll also need to write some code to populate it from DT properties. It shouldn't take more than a few minutes per driver in most cases.
To get those drivers accepted upstream will obviously take a bit more work.
-- Måns Rullgård mans@mansr.com
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