On Fri, Oct 4, 2013 at 11:01 AM, Inki Dae <inki.dae@xxxxxxxxxxx> wrote: > > >> -----Original Message----- >> From: Sean Paul [mailto:seanpaul@xxxxxxxxxxxx] >> Sent: Friday, October 04, 2013 11:17 PM >> To: Inki Dae >> Cc: Kukjin Kim; DRI mailing list; linux-samsung-soc@xxxxxxxxxxxxxxx; >> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux- >> doc@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; Dave Airlie >> Subject: Re: [PATCH v2 4/5] drm/exynos: Initialize ptn3460 if present >> >> On Fri, Oct 4, 2013 at 12:18 AM, Inki Dae <inki.dae@xxxxxxxxxxx> wrote: >> > 2013/10/4 Sean Paul <seanpaul@xxxxxxxxxxxx>: >> >> On Thu, Oct 3, 2013 at 10:29 PM, Inki Dae <inki.dae@xxxxxxxxxxx> wrote: >> >>> 2013/10/4 Sean Paul <seanpaul@xxxxxxxxxxxx>: >> >>>> This patch adds code to look for the ptn3460 in the device tree file >> on >> >>>> exynos initialization. If ptn node is found, the driver will >> initialize >> >>>> the ptn3460 driver and skip creating a DP connector (since the bridge >> >>>> driver will register its own connector). >> >>>> >> >>>> Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx> >> >>>> --- >> >>>> >> >>>> v2: >> >>>> - Changed include from of_i2c.h to i2c.h >> >>>> - Changed of_find_by_name to of_find_compatible >> >>>> >> >>>> drivers/gpu/drm/exynos/exynos_drm_core.c | 44 >> +++++++++++++++++++++++++++++++- >> >>>> 1 file changed, 43 insertions(+), 1 deletion(-) >> >>>> >> >>>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_core.c >> b/drivers/gpu/drm/exynos/exynos_drm_core.c >> >>>> index 1bef6dc..08ca4f9 100644 >> >>>> --- a/drivers/gpu/drm/exynos/exynos_drm_core.c >> >>>> +++ b/drivers/gpu/drm/exynos/exynos_drm_core.c >> >>>> @@ -12,7 +12,9 @@ >> >>>> * option) any later version. >> >>>> */ >> >>>> >> >>>> +#include <linux/i2c.h> >> >>>> #include <drm/drmP.h> >> >>>> +#include <drm/bridge/ptn3460.h> >> >>>> #include "exynos_drm_drv.h" >> >>>> #include "exynos_drm_encoder.h" >> >>>> #include "exynos_drm_connector.h" >> >>>> @@ -20,6 +22,40 @@ >> >>>> >> >>>> static LIST_HEAD(exynos_drm_subdrv_list); >> >>>> >> >>>> +struct bridge_init { >> >>>> + struct i2c_client *client; >> >>>> + struct device_node *node; >> >>>> +}; >> >>>> + >> >>>> +static bool find_bridge(const char *compat, struct bridge_init >> *bridge) >> >>>> +{ >> >>>> + bridge->client = NULL; >> >>>> + bridge->node = of_find_compatible_node(NULL, NULL, compat); >> >>> >> >>> Then, shouldn't the lvds-bridge driver be implemented as i2c driver so >> >>> that such tricky isn't needed? Is there any reason you use such tricky >> >>> codes? >> >>> >> >> >> >> This is what I was explaining earlier today. If the bridge driver is >> >> just an i2c driver, it won't get a pointer to drm_device, and can't >> >> register itself as a drm_bridge or drm_connector. To solve this, you >> >> need the ptn3460_init callback. >> >> >> > >> > No, I think you can use sub driver. how about registering to exynos >> > drm core that driver using exynos_drm_subdrv_register function after >> > probed? Is there something I am missing? >> > >> >> The ptn driver isn't exynos-specific, so I don't think making it an >> exynos_drm_subdrv is appropriate. >> > > I _really know_ that the ptn driver isn't exynos-specific. I mean that you > can use exynos_drm_subdrv somehow. ie. you can add a new bridge module > specific to exynos, and this module can register its own sub driver at end > of probe. Why do you try to use such tricky codes? > So I create a new exynos_lvds_driver which is an i2c driver. When that probes, all it does is register that driver as an exynos_drm_subdrv. Then in the subdrv probe I call into ptn3460_init? That seems a lot more tricky than just calling ptn3460_init directly... Sean > Thanks, > Inki Dae > >> Sean >> >> > >> >> If it's an i2c driver with the ptn3460_init callback, where it parses >> >> the dt in probe, then you have a race between the ptn probe and the >> >> ptn init/drm hooks. ie: it's possible drm will initialize and call >> >> disable/post_disable/pre_enable/enable before things have been probed. >> > >> > And also, exynos drm core will call a probe callback of the sub driver >> > after _drm is initialized_. Is there something I am missing? >> > >> >> To solve this, you need to use some global state and/or locking. >> >> >> >> So, to summarize. We can have this of_find_compatible with a init >> >> callback, or we can have an i2c driver + global state/locking + init >> >> callback. I chose the former, since it seemed easier. >> >> >> >> If you have a better way to achieve this, I'm definitely interested, >> >> but I saw this as the lesser of two evils. >> >> >> >> Sean >> >> >> >>> I think you need to implement the lvds-bridge driver as i2c driver, >> >>> and then consider how to take care of this. I mean let's find a better >> >>> way how we could take care of the i2c based driver in exynos drm >> >>> framework or driver. In all cases, such tricky codes are not good. >> >>> >> >>>> + if (!bridge->node) >> >>>> + return false; >> >>>> + >> >>>> + bridge->client = of_find_i2c_device_by_node(bridge->node); >> >>>> + if (!bridge->client) >> >>>> + return false; >> >>>> + >> >>>> + return true; >> >>>> +} >> >>>> + >> >>>> +/* returns the number of bridges attached */ >> >>>> +static int exynos_drm_attach_lcd_bridge(struct drm_device *dev, >> >>>> + struct drm_encoder *encoder) >> >>>> +{ >> >>>> + struct bridge_init bridge; >> >>>> + int ret; >> >>>> + >> >>>> + if (find_bridge("nxp,ptn3460", &bridge)) { >> >>>> + ret = ptn3460_init(dev, encoder, bridge.client, >> bridge.node); >> >>>> + if (!ret) >> >>>> + return 1; >> >>>> + } >> >>>> + return 0; >> >>>> +} >> >>>> + >> >>>> static int exynos_drm_create_enc_conn(struct drm_device *dev, >> >>>> struct exynos_drm_subdrv > *subdrv) >> >>>> { >> >>>> @@ -36,6 +72,13 @@ static int exynos_drm_create_enc_conn(struct >> drm_device *dev, >> >>>> DRM_ERROR("failed to create encoder\n"); >> >>>> return -EFAULT; >> >>>> } >> >>>> + subdrv->encoder = encoder; >> >>>> + >> >>>> + if (subdrv->manager->display_ops->type == >> EXYNOS_DISPLAY_TYPE_LCD) { >> >>>> + ret = exynos_drm_attach_lcd_bridge(dev, encoder); >> >>>> + if (ret) >> >>>> + return 0; >> >>>> + } >> >>>> >> >>>> /* >> >>>> * create and initialize a connector for this sub driver and >> >>>> @@ -48,7 +91,6 @@ static int exynos_drm_create_enc_conn(struct >> drm_device *dev, >> >>>> goto err_destroy_encoder; >> >>>> } >> >>>> >> >>>> - subdrv->encoder = encoder; >> >>>> subdrv->connector = connector; >> >>>> >> >>>> return 0; >> >>>> -- >> >>>> 1.8.4 >> >>>> >> >>>> -- >> >>>> To unsubscribe from this list: send the line "unsubscribe linux- >> samsung-soc" in >> >>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >> >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> -- >> >> To unsubscribe from this list: send the line "unsubscribe linux- >> samsung-soc" in >> >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
