diff options
Diffstat (limited to 'drivers/media/platform/rcar-fcp.c')
| -rw-r--r-- | drivers/media/platform/rcar-fcp.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/drivers/media/platform/rcar-fcp.c b/drivers/media/platform/rcar-fcp.c new file mode 100644 index 000000000000..6a7bcc3028b1 --- /dev/null +++ b/drivers/media/platform/rcar-fcp.c @@ -0,0 +1,181 @@ +/* + * rcar-fcp.c -- R-Car Frame Compression Processor Driver + * + * Copyright (C) 2016 Renesas Electronics Corporation + * + * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <linux/device.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/slab.h> + +#include <media/rcar-fcp.h> + +struct rcar_fcp_device { + struct list_head list; + struct device *dev; +}; + +static LIST_HEAD(fcp_devices); +static DEFINE_MUTEX(fcp_lock); + +/* ----------------------------------------------------------------------------- + * Public API + */ + +/** + * rcar_fcp_get - Find and acquire a reference to an FCP instance + * @np: Device node of the FCP instance + * + * Search the list of registered FCP instances for the instance corresponding to + * the given device node. + * + * Return a pointer to the FCP instance, or an ERR_PTR if the instance can't be + * found. + */ +struct rcar_fcp_device *rcar_fcp_get(const struct device_node *np) +{ + struct rcar_fcp_device *fcp; + + mutex_lock(&fcp_lock); + + list_for_each_entry(fcp, &fcp_devices, list) { + if (fcp->dev->of_node != np) + continue; + + /* + * Make sure the module won't be unloaded behind our back. This + * is a poor man's safety net, the module should really not be + * unloaded while FCP users can be active. + */ + if (!try_module_get(fcp->dev->driver->owner)) + fcp = NULL; + + goto done; + } + + fcp = ERR_PTR(-EPROBE_DEFER); + +done: + mutex_unlock(&fcp_lock); + return fcp; +} +EXPORT_SYMBOL_GPL(rcar_fcp_get); + +/** + * rcar_fcp_put - Release a reference to an FCP instance + * @fcp: The FCP instance + * + * Release the FCP instance acquired by a call to rcar_fcp_get(). + */ +void rcar_fcp_put(struct rcar_fcp_device *fcp) +{ + if (fcp) + module_put(fcp->dev->driver->owner); +} +EXPORT_SYMBOL_GPL(rcar_fcp_put); + +/** + * rcar_fcp_enable - Enable an FCP + * @fcp: The FCP instance + * + * Before any memory access through an FCP is performed by a module, the FCP + * must be enabled by a call to this function. The enable calls are reference + * counted, each successful call must be followed by one rcar_fcp_disable() + * call when no more memory transfer can occur through the FCP. + * + * Return 0 on success or a negative error code if an error occurs. The enable + * reference count isn't increased when this function returns an error. + */ +int rcar_fcp_enable(struct rcar_fcp_device *fcp) +{ + if (!fcp) + return 0; + + return pm_runtime_get_sync(fcp->dev); +} +EXPORT_SYMBOL_GPL(rcar_fcp_enable); + +/** + * rcar_fcp_disable - Disable an FCP + * @fcp: The FCP instance + * + * This function is the counterpart of rcar_fcp_enable(). As enable calls are + * reference counted a disable call may not disable the FCP synchronously. + */ +void rcar_fcp_disable(struct rcar_fcp_device *fcp) +{ + if (fcp) + pm_runtime_put(fcp->dev); +} +EXPORT_SYMBOL_GPL(rcar_fcp_disable); + +/* ----------------------------------------------------------------------------- + * Platform Driver + */ + +static int rcar_fcp_probe(struct platform_device *pdev) +{ + struct rcar_fcp_device *fcp; + + fcp = devm_kzalloc(&pdev->dev, sizeof(*fcp), GFP_KERNEL); + if (fcp == NULL) + return -ENOMEM; + + fcp->dev = &pdev->dev; + + pm_runtime_enable(&pdev->dev); + + mutex_lock(&fcp_lock); + list_add_tail(&fcp->list, &fcp_devices); + mutex_unlock(&fcp_lock); + + platform_set_drvdata(pdev, fcp); + + return 0; +} + +static int rcar_fcp_remove(struct platform_device *pdev) +{ + struct rcar_fcp_device *fcp = platform_get_drvdata(pdev); + + mutex_lock(&fcp_lock); + list_del(&fcp->list); + mutex_unlock(&fcp_lock); + + pm_runtime_disable(&pdev->dev); + + return 0; +} + +static const struct of_device_id rcar_fcp_of_match[] = { + { .compatible = "renesas,fcpv" }, + { }, +}; + +static struct platform_driver rcar_fcp_platform_driver = { + .probe = rcar_fcp_probe, + .remove = rcar_fcp_remove, + .driver = { + .name = "rcar-fcp", + .of_match_table = rcar_fcp_of_match, + .suppress_bind_attrs = true, + }, +}; + +module_platform_driver(rcar_fcp_platform_driver); + +MODULE_ALIAS("rcar-fcp"); +MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>"); +MODULE_DESCRIPTION("Renesas FCP Driver"); +MODULE_LICENSE("GPL"); |