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Fix imx6 hdmi init after r323553, which used a config_intrhook to defer the

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attachment of i2c devices needed by hdmi.

The hdmi init also uses an intrhook callback to defer initialization, and if
the hdmi callback runs first, the i2c devices will not yet have registered
their device_t in association with their FDT phandle, which allows cross-
device references on FDT systems.

Now the hdmi deferred init checks for the i2c device registration, and if
it's not complete yet, it registers as an eventhandler watching for newbus
attach events.  When the i2c device eventually attaches, the hdmi driver
unregisters from watching further events, and continues with the hdmi init.
Because the function signatures for an intrhook callback and an event
handler callback are the same, a single function is used for both callbacks.

Reported by:	Russell Haley <russ.haley@gmail.com>
This commit is contained in:
Ian Lepore 2017-10-08 18:38:22 +00:00
parent 7f92689427
commit 7e7ef41632
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=324416
1 changed files with 47 additions and 1 deletions
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48
sys/arm/freescale/imx/imx6_hdmi.c
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@ -33,6 +33,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/bus.h>
@ -57,6 +58,7 @@ __FBSDID("$FreeBSD$");
struct imx_hdmi_softc {
struct dwc_hdmi_softc base;
phandle_t i2c_xref;
eventhandler_tag eh_tag;
};
static struct ofw_compat_data compat_data[] = {
@ -78,6 +80,48 @@ imx_hdmi_get_i2c_dev(device_t dev)
return (OF_device_from_xref(sc->i2c_xref));
}
/*
* Deferred HDMI init. dwc_hdmi_init() does i2c transfers for DDC/EDID. The imx
* i2c devices also use a config_intrhook function to finish their init, because
* they require interrupts to perform transfers. There is no way to control
* whether the i2c or our hdmi intrhook function runs first. If we go first we
* have to continue waiting until after the i2c driver is ready to do transfers
* and has registered its phandle.
*
* This function is used as both a config_intrhook function and after that as an
* eventhandler callback function (if necessary), to see if our i2c device is
* ready yet. When it is, continue with hdmi init. When first called as an
* intrhook function the i2c devices might be ready, in which case we never
* register as an eventhandler at all. Otherwise we register to see newbus
* attach events, and as each device attaches we check to see whether it was the
* i2c device we care about. Once we have our i2c device we unregister from
* seeing further attach events.
*/
static void
imx_hdmi_init(void *dev)
{
struct imx_hdmi_softc *sc;
sc = device_get_softc((device_t)dev);
if (OF_device_from_xref(sc->i2c_xref) != NULL) {
if (sc->eh_tag != NULL) {
EVENTHANDLER_DEREGISTER_NOWAIT(device_attach,
sc->eh_tag);
}
dwc_hdmi_init(dev);
return;
}
if (bootverbose)
device_printf((device_t)dev, "Waiting for DDC i2c device\n");
if (sc->eh_tag == NULL) {
sc->eh_tag = EVENTHANDLER_REGISTER(device_attach,
imx_hdmi_init, dev, EVENTHANDLER_PRI_ANY);
}
}
static int
imx_hdmi_detach(device_t dev)
{
@ -128,7 +172,9 @@ imx_hdmi_attach(device_t dev)
gpr3 |= IOMUXC_GPR3_HDMI_IPU1_DI0;
imx_iomux_gpr_set(IOMUXC_GPR3, gpr3);
return (dwc_hdmi_init(dev));
/* Further HDMI init requires interrupts for i2c transfers. */
config_intrhook_oneshot(imx_hdmi_init, dev);
return (0);
out:
imx_hdmi_detach(dev);