Messages in this thread | | | Subject | Re: Grafting old platform drivers onto a new DT kernel | From | Mason <> | Date | Mon, 9 Nov 2015 18:03:47 +0100 |
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On 09/11/2015 17:12, Måns Rullgård wrote:
> Mason writes: > >> On 09/11/2015 16:40, Måns Rullgård wrote: >> >>> 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. >> >> I'll try that approach, although I fear that "a few minutes per driver" >> is an optimistic assessment. > > If the driver only needs an MMIO region and an IRQ, it is literally five > lines of code.
It took me 7 days to figure out there were 2 lines missing in the interrupt controller driver.
My problem is that I don't understand the platform API, nor the interaction with the DT API.
Let me see...
In arch/arm/mach-tangox/platform_dev.c
static struct platform_device tangox_sdhci0_device = { ... }; static struct platform_device tangox_sdhci1_device = { ... };
static void tangox_init_sdhci(void) { if (tangox_sdio_enabled(0)) platform_device_register(&tangox_sdhci0_device);
if (tangox_sdio_enabled(1)) platform_device_register(&tangox_sdhci1_device); }
called from tangox_init_devices() which is marked arch_initcall.
In the driver
static struct platform_driver tangox_platform_sdio0 = { .remove = sdhci_tangox_remove, .suspend = sdhci_tangox_suspend, .resume = sdhci_tangox_resume, .driver = { .name = "tangox-sdhci", .owner = THIS_MODULE, }, };
static struct platform_driver tangox_platform_sdio0 = { .remove = sdhci_tangox_remove, .driver = { .name = "tangox-sdhci", .owner = THIS_MODULE, }, };
static int __init tangox_sdhci_drv_init(void) { return platform_driver_probe(&tangox_platform_sdio0, sdhci_tangox_probe); }
static void __exit tangox_sdhci_drv_exit(void) { platform_driver_unregister(&tangox_platform_sdio0); }
module_init(tangox_sdhci_drv_init); module_exit(tangox_sdhci_drv_exit);
The old way:
1) call platform_device_register() with a "struct platform_device" 2) call platform_driver_probe with a "struct platform_driver"
The new way(?)
The mess in 2) is hidden behind module_platform_driver? The platform_device_register() is done by the DT core? The struct platform_driver requires a probe function?
Regards.
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