From: Bartosz Golaszewski <[email protected]> Implement a very simple early platform driver. Its purpose is to show how such drivers can be registered and to emit a message when probed.
It can be then added to the device tree or machine code to verify that the early platform devices work as expected. Signed-off-by: Bartosz Golaszewski <[email protected]> --- drivers/misc/Kconfig | 8 ++++ drivers/misc/Makefile | 1 + drivers/misc/dummy-early.c | 82 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 91 insertions(+) create mode 100644 drivers/misc/dummy-early.c diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 5d713008749b..60fef04eb236 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -91,6 +91,14 @@ config DUMMY_IRQ The sole purpose of this module is to help with debugging of systems on which spurious IRQs would happen on disabled IRQ vector. +config DUMMY_EARLY + bool "Dummy early platform driver" + select EARLY_PLATFORM + default n + help + This module's only function is to register itself with the early + platform device framework and be probed early in the boot process. + config IBM_ASM tristate "Device driver for IBM RSA service processor" depends on X86 && PCI && INPUT diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index d0a8788d5151..6170855853a1 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -11,6 +11,7 @@ obj-$(CONFIG_INTEL_MID_PTI) += pti.o obj-$(CONFIG_ATMEL_SSC) += atmel-ssc.o obj-$(CONFIG_ATMEL_TCLIB) += atmel_tclib.o obj-$(CONFIG_DUMMY_IRQ) += dummy-irq.o +obj-$(CONFIG_DUMMY_EARLY) += dummy-early.o obj-$(CONFIG_ICS932S401) += ics932s401.o obj-$(CONFIG_LKDTM) += lkdtm/ obj-$(CONFIG_TIFM_CORE) += tifm_core.o diff --git a/drivers/misc/dummy-early.c b/drivers/misc/dummy-early.c new file mode 100644 index 000000000000..eb8f826aea64 --- /dev/null +++ b/drivers/misc/dummy-early.c @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018 Texas Instruments + * + * Author: + * Bartosz Golaszewski <[email protected]> + * + * Dummy testing driver whose only purpose is to be registered and probed + * using the early platform device mechanism. + */ + +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/early_platform.h> + +struct dummy_early_data { + int a; + int b; +}; + +static int dummy_early_probe_early(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct dummy_early_data *data; + struct resource *res; + + dev_notice(dev, "dummy-early driver probed early!\n"); + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->a = 123; + data->b = 321; + + dev_dbg(dev, "setting driver data early: a = %d, b = %d\n", + data->a, data->b); + dev_set_drvdata(dev, data); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (res) + dev_dbg(dev, "got early resource: start = 0x%08x, end = 0x%08x\n", + res->start, res->end); + + return 0; +} + +static int dummy_early_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct dummy_early_data *data; + + dev_notice(dev, "dummy-early driver probed late!\n"); + data = dev_get_drvdata(dev); + dev_dbg(dev, "retrieving driver data late: a = %d, b = %d\n", + data->a, data->b); + + return 0; +} + +static const struct of_device_id dummy_early_of_match[] = { + { .compatible = "dummy-early", }, + { }, +}; + +static struct early_platform_driver dummy_early_driver = { + .early_probe = dummy_early_probe_early, + .pdrv = { + .probe = dummy_early_probe, + .driver = { + .name = "dummy-early", + .of_match_table = dummy_early_of_match, + }, + } +}; +module_early_platform_driver(dummy_early_driver); + +MODULE_AUTHOR("Bartosz Golaszewski <[email protected]>"); +MODULE_DESCRIPTION("Dummy early platform device driver"); +MODULE_LICENSE("GPL v2"); -- 2.17.0
