linux/drivers/gpu/drm/omapdrm/dss/core.c

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/*
* linux/drivers/video/omap2/dss/core.c
*
* Copyright (C) 2009 Nokia Corporation
* Author: Tomi Valkeinen <tomi.valkeinen@nokia.com>
*
* Some code and ideas taken from drivers/video/omap/ driver
* by Imre Deak.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#define DSS_SUBSYS_NAME "CORE"
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/regulator/consumer.h>
OMAPDSS: Use PM notifiers for system suspend The current way how omapdss handles system suspend and resume is that omapdss device (a platform device, which is not part of the device hierarchy of the DSS HW devices, like DISPC and DSI, or panels.) uses the suspend and resume callbacks from platform_driver to handle system suspend. It does this by disabling all enabled panels on suspend, and resuming the previously disabled panels on resume. This presents a few problems. One is that as omapdss device is not related to the panel devices or the DSS HW devices, there's no ordering in the suspend process. This means that suspend could be first ran for DSS HW devices and panels, and only then for omapdss device. Currently this is not a problem, as DSS HW devices and panels do not handle suspend. Another, more pressing problem, is that when suspending or resuming, the runtime PM functions return -EACCES as runtime PM is disabled during system suspend. This causes the driver to print warnings, and operations to fail as they think that they failed to bring up the HW. This patch changes the omapdss suspend handling to use PM notifiers, which are called before suspend and after resume. This way we have a normally functioning system when we are suspending and resuming the panels. This patch, I believe, creates a problem that somebody could enable or disable a panel between PM_SUSPEND_PREPARE and the system suspend, and similarly the other way around in resume. I choose to ignore the problem for now, as it sounds rather unlikely, and if it happens, it's not fatal. In the long run the system suspend handling of omapdss and panels should be thought out properly. The current approach feels rather hacky. Perhaps the panel drivers should handle system suspend, or the users of omapdss (omapfb, omapdrm) should handle system suspend. Note that after this patch we could probably revert 0eaf9f52e94f756147dbfe1faf1f77a02378dbf9 (OMAPDSS: use sync versions of pm_runtime_put). But as I said, this patch may be temporary, so let's leave the sync version still in place. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com> Reported-by: Jassi Brar <jaswinder.singh@linaro.org> Tested-by: Jassi Brar <jaswinder.singh@linaro.org> Tested-by: Joe Woodward <jw@terrafix.co.uk> Signed-off-by: Archit Taneja <archit@ti.com> [fts: fixed 2 brace coding style issues] Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
2012-07-04 12:43:48 +00:00
#include <linux/suspend.h>
#include <linux/slab.h>
#include "omapdss.h"
#include "dss.h"
static struct {
struct platform_device *pdev;
} core;
enum omapdss_version omapdss_get_version(void)
{
struct omap_dss_board_info *pdata = core.pdev->dev.platform_data;
return pdata->version;
}
EXPORT_SYMBOL(omapdss_get_version);
/* PLATFORM DEVICE */
OMAPDSS: Use PM notifiers for system suspend The current way how omapdss handles system suspend and resume is that omapdss device (a platform device, which is not part of the device hierarchy of the DSS HW devices, like DISPC and DSI, or panels.) uses the suspend and resume callbacks from platform_driver to handle system suspend. It does this by disabling all enabled panels on suspend, and resuming the previously disabled panels on resume. This presents a few problems. One is that as omapdss device is not related to the panel devices or the DSS HW devices, there's no ordering in the suspend process. This means that suspend could be first ran for DSS HW devices and panels, and only then for omapdss device. Currently this is not a problem, as DSS HW devices and panels do not handle suspend. Another, more pressing problem, is that when suspending or resuming, the runtime PM functions return -EACCES as runtime PM is disabled during system suspend. This causes the driver to print warnings, and operations to fail as they think that they failed to bring up the HW. This patch changes the omapdss suspend handling to use PM notifiers, which are called before suspend and after resume. This way we have a normally functioning system when we are suspending and resuming the panels. This patch, I believe, creates a problem that somebody could enable or disable a panel between PM_SUSPEND_PREPARE and the system suspend, and similarly the other way around in resume. I choose to ignore the problem for now, as it sounds rather unlikely, and if it happens, it's not fatal. In the long run the system suspend handling of omapdss and panels should be thought out properly. The current approach feels rather hacky. Perhaps the panel drivers should handle system suspend, or the users of omapdss (omapfb, omapdrm) should handle system suspend. Note that after this patch we could probably revert 0eaf9f52e94f756147dbfe1faf1f77a02378dbf9 (OMAPDSS: use sync versions of pm_runtime_put). But as I said, this patch may be temporary, so let's leave the sync version still in place. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com> Reported-by: Jassi Brar <jaswinder.singh@linaro.org> Tested-by: Jassi Brar <jaswinder.singh@linaro.org> Tested-by: Joe Woodward <jw@terrafix.co.uk> Signed-off-by: Archit Taneja <archit@ti.com> [fts: fixed 2 brace coding style issues] Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
2012-07-04 12:43:48 +00:00
static int __init omap_dss_probe(struct platform_device *pdev)
{
core.pdev = pdev;
return 0;
}
static int omap_dss_remove(struct platform_device *pdev)
{
return 0;
}
static struct platform_driver omap_dss_driver = {
.remove = omap_dss_remove,
.driver = {
.name = "omapdss",
},
};
/* INIT */
static int (*dss_output_drv_reg_funcs[])(void) __initdata = {
dss_init_platform_driver,
dispc_init_platform_driver,
#ifdef CONFIG_OMAP2_DSS_DSI
dsi_init_platform_driver,
#endif
#ifdef CONFIG_OMAP2_DSS_VENC
venc_init_platform_driver,
#endif
#ifdef CONFIG_OMAP4_DSS_HDMI
hdmi4_init_platform_driver,
#endif
#ifdef CONFIG_OMAP5_DSS_HDMI
hdmi5_init_platform_driver,
#endif
};
static void (*dss_output_drv_unreg_funcs[])(void) = {
#ifdef CONFIG_OMAP5_DSS_HDMI
hdmi5_uninit_platform_driver,
#endif
#ifdef CONFIG_OMAP4_DSS_HDMI
hdmi4_uninit_platform_driver,
#endif
#ifdef CONFIG_OMAP2_DSS_VENC
venc_uninit_platform_driver,
#endif
#ifdef CONFIG_OMAP2_DSS_DSI
dsi_uninit_platform_driver,
#endif
dispc_uninit_platform_driver,
dss_uninit_platform_driver,
};
static int __init omap_dss_init(void)
{
int r;
int i;
r = platform_driver_probe(&omap_dss_driver, omap_dss_probe);
if (r)
return r;
for (i = 0; i < ARRAY_SIZE(dss_output_drv_reg_funcs); ++i) {
r = dss_output_drv_reg_funcs[i]();
if (r)
goto err_reg;
}
return 0;
err_reg:
for (i = ARRAY_SIZE(dss_output_drv_reg_funcs) - i;
i < ARRAY_SIZE(dss_output_drv_reg_funcs);
++i)
dss_output_drv_unreg_funcs[i]();
platform_driver_unregister(&omap_dss_driver);
return r;
}
static void __exit omap_dss_exit(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(dss_output_drv_unreg_funcs); ++i)
dss_output_drv_unreg_funcs[i]();
platform_driver_unregister(&omap_dss_driver);
}
module_init(omap_dss_init);
module_exit(omap_dss_exit);
MODULE_AUTHOR("Tomi Valkeinen <tomi.valkeinen@nokia.com>");
MODULE_DESCRIPTION("OMAP2/3 Display Subsystem");
MODULE_LICENSE("GPL v2");