Commit bf73537f authored by Douglas Anderson's avatar Douglas Anderson
Browse files

drm/bridge: ti-sn65dsi86: Break GPIO and MIPI-to-eDP bridge into sub-drivers 



Let's use the newly minted aux bus to break up the driver into sub
drivers. We're not doing a full breakup here: all the code is still in
the same file and remains largely untouched. The big goal here of
using sub-drivers is to allow part of our code to finish probing even
if some other code needs to defer. This can solve some chicken-and-egg
problems. Specifically:
- In commit 48834e60 ("drm/panel-simple: Support hpd-gpios for
  delaying prepare()") we had to add a bit of a hack to simpel-panel
  to support HPD showing up late. We can get rid of that hack now
  since the GPIO part of our driver can finish probing early.
- We have a desire to expose our DDC bus to simple-panel (and perhaps
  to a backlight driver?). That will end up with the same
  chicken-and-egg problem. A future patch to move this to a sub-driver
  will fix it.
- If/when we support the PWM functionality present in the bridge chip
  for a backlight we'll end up with another chicken-and-egg
  problem. If we allow the PWM to be a sub-driver too then it solves
  this problem.

Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210423095743.v5.9.I3e68fa38c4ccbdbdf145cad2b01e83a1e5eac302@changeid
parent bef236a5

drivers/gpu/drm/bridge/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -278,6 +278,7 @@ config DRM_TI_SN65DSI86 
	select REGMAP_I2C

	select DRM_PANEL

	select DRM_MIPI_DSI

	select AUXILIARY_BUS

	help

	  Texas Instruments SN65DSI86 DSI to eDP Bridge driver

drivers/gpu/drm/bridge/ti-sn65dsi86.c

+199 −53
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
 * datasheet: https://www.ti.com/lit/ds/symlink/sn65dsi86.pdf

 */



#include <linux/auxiliary_bus.h>

#include <linux/bits.h>

#include <linux/clk.h>

#include <linux/debugfs.h>
@@ -113,7 +114,10 @@ 


/**

 * struct ti_sn65dsi86 - Platform data for ti-sn65dsi86 driver.

 * @dev:          Pointer to our device.

 * @bridge_aux:   AUX-bus sub device for MIPI-to-eDP bridge functionality.

 * @gpio_aux:     AUX-bus sub device for GPIO controller functionality.

 *

 * @dev:          Pointer to the top level (i2c) device.

 * @regmap:       Regmap for accessing i2c.

 * @aux:          Our aux channel.

 * @bridge:       Our bridge.
@@ -140,6 +144,9 @@ 
 *                each other's read-modify-write.

 */

struct ti_sn65dsi86 {

	struct auxiliary_device		bridge_aux;

	struct auxiliary_device		gpio_aux;



	struct device			*dev;

	struct regmap			*regmap;

	struct drm_dp_aux		aux;
@@ -1137,8 +1144,10 @@ static const char * const ti_sn_bridge_gpio_names[SN_NUM_GPIOS] = { 
	"GPIO1", "GPIO2", "GPIO3", "GPIO4"

};



static int ti_sn_setup_gpio_controller(struct ti_sn65dsi86 *pdata)

static int ti_sn_gpio_probe(struct auxiliary_device *adev,

			    const struct auxiliary_device_id *id)

{

	struct ti_sn65dsi86 *pdata = dev_get_drvdata(adev->dev.parent);

	int ret;



	/* Only init if someone is going to use us as a GPIO controller */
@@ -1160,20 +1169,41 @@ static int ti_sn_setup_gpio_controller(struct ti_sn65dsi86 *pdata) 
	pdata->gchip.names = ti_sn_bridge_gpio_names;

	pdata->gchip.ngpio = SN_NUM_GPIOS;

	pdata->gchip.base = -1;

	ret = devm_gpiochip_add_data(pdata->dev, &pdata->gchip, pdata);

	ret = devm_gpiochip_add_data(&adev->dev, &pdata->gchip, pdata);

	if (ret)

		dev_err(pdata->dev, "can't add gpio chip\n");



	return ret;

}



#else

static const struct auxiliary_device_id ti_sn_gpio_id_table[] = {

	{ .name = "ti_sn65dsi86.gpio", },

	{},

};



static inline int ti_sn_setup_gpio_controller(struct ti_sn65dsi86 *pdata)

MODULE_DEVICE_TABLE(auxiliary, ti_sn_gpio_id_table);



static struct auxiliary_driver ti_sn_gpio_driver = {

	.name = "gpio",

	.probe = ti_sn_gpio_probe,

	.id_table = ti_sn_gpio_id_table,

};



static int __init ti_sn_gpio_register(void)

{

	return 0;

	return auxiliary_driver_register(&ti_sn_gpio_driver);

}



static void __exit ti_sn_gpio_unregister(void)

{

	auxiliary_driver_unregister(&ti_sn_gpio_driver);

}



#else



static inline int ti_sn_gpio_register(void) { return 0; }

static inline void ti_sn_gpio_unregister(void) {}



#endif



static void ti_sn_bridge_parse_lanes(struct ti_sn65dsi86 *pdata,
@@ -1225,11 +1255,124 @@ static void ti_sn_bridge_parse_lanes(struct ti_sn65dsi86 *pdata, 
	pdata->ln_polrs = ln_polrs;

}



static int ti_sn_bridge_probe(struct auxiliary_device *adev,

			      const struct auxiliary_device_id *id)

{

	struct ti_sn65dsi86 *pdata = dev_get_drvdata(adev->dev.parent);

	struct device_node *np = pdata->dev->of_node;

	int ret;



	ret = drm_of_find_panel_or_bridge(np, 1, 0, &pdata->panel, NULL);

	if (ret) {

		DRM_ERROR("could not find any panel node\n");

		return ret;

	}



	ti_sn_bridge_parse_lanes(pdata, np);



	ret = ti_sn_bridge_parse_dsi_host(pdata);

	if (ret)

		return ret;



	pdata->aux.name = "ti-sn65dsi86-aux";

	pdata->aux.dev = pdata->dev;

	pdata->aux.transfer = ti_sn_aux_transfer;

	drm_dp_aux_init(&pdata->aux);



	pdata->bridge.funcs = &ti_sn_bridge_funcs;

	pdata->bridge.of_node = np;



	drm_bridge_add(&pdata->bridge);



	return 0;

}



static void ti_sn_bridge_remove(struct auxiliary_device *adev)

{

	struct ti_sn65dsi86 *pdata = dev_get_drvdata(adev->dev.parent);



	if (!pdata)

		return;



	if (pdata->dsi) {

		mipi_dsi_detach(pdata->dsi);

		mipi_dsi_device_unregister(pdata->dsi);

	}



	kfree(pdata->edid);



	drm_bridge_remove(&pdata->bridge);



	of_node_put(pdata->host_node);

}



static const struct auxiliary_device_id ti_sn_bridge_id_table[] = {

	{ .name = "ti_sn65dsi86.bridge", },

	{},

};



static struct auxiliary_driver ti_sn_bridge_driver = {

	.name = "bridge",

	.probe = ti_sn_bridge_probe,

	.remove = ti_sn_bridge_remove,

	.id_table = ti_sn_bridge_id_table,

};



static void ti_sn65dsi86_runtime_disable(void *data)

{

	pm_runtime_disable(data);

}



static void ti_sn65dsi86_uninit_aux(void *data)

{

	auxiliary_device_uninit(data);

}



static void ti_sn65dsi86_delete_aux(void *data)

{

	auxiliary_device_delete(data);

}



/*

 * AUX bus docs say that a non-NULL release is mandatory, but it makes no

 * sense for the model used here where all of the aux devices are allocated

 * in the single shared structure. We'll use this noop as a workaround.

 */

static void ti_sn65dsi86_noop(struct device *dev) {}



static int ti_sn65dsi86_add_aux_device(struct ti_sn65dsi86 *pdata,

				       struct auxiliary_device *aux,

				       const char *name)

{

	struct device *dev = pdata->dev;

	int ret;



	/*

	 * NOTE: It would be nice to set the "of_node" of our children to be

	 * the same "of_node"" that the top-level component has. That doesn't

	 * work, though, since pinctrl will try (and fail) to reserve the

	 * pins again. Until that gets sorted out the children will just need

	 * to look at the of_node of the main device.

	 */



	aux->name = name;

	aux->dev.parent = dev;

	aux->dev.release = ti_sn65dsi86_noop;

	ret = auxiliary_device_init(aux);

	if (ret)

		return ret;

	ret = devm_add_action_or_reset(dev, ti_sn65dsi86_uninit_aux, aux);

	if (ret)

		return ret;



	ret = auxiliary_device_add(aux);

	if (ret)

		return ret;

	ret = devm_add_action_or_reset(dev, ti_sn65dsi86_delete_aux, aux);



	return ret;

}



static int ti_sn65dsi86_probe(struct i2c_client *client,

			      const struct i2c_device_id *id)

{
@@ -1279,54 +1422,24 @@ static int ti_sn65dsi86_probe(struct i2c_client *client, 


	ti_sn65dsi86_debugfs_init(pdata);



	ret = drm_of_find_panel_or_bridge(dev->of_node, 1, 0, &pdata->panel, NULL);

	if (ret) {

		DRM_ERROR("could not find any panel node\n");

		return ret;

	}



	ti_sn_bridge_parse_lanes(pdata, dev->of_node);



	ret = ti_sn_bridge_parse_dsi_host(pdata);

	if (ret)

		return ret;

	/*

	 * Break ourselves up into a collection of aux devices. The only real

	 * motiviation here is to solve the chicken-and-egg problem of probe

	 * ordering. The bridge wants the panel to be there when it probes.

	 * The panel wants its HPD GPIO (provided by sn65dsi86 on some boards)

	 * when it probes. There will soon be other devices (DDC I2C bus, PWM)

	 * that have the same problem. Having sub-devices allows the some sub

	 * devices to finish probing even if others return -EPROBE_DEFER and

	 * gets us around the problems.

	 */



	ret = ti_sn_setup_gpio_controller(pdata);

	if (IS_ENABLED(CONFIG_OF_GPIO)) {

		ret = ti_sn65dsi86_add_aux_device(pdata, &pdata->gpio_aux, "gpio");

		if (ret)

			return ret;



	pdata->aux.name = "ti-sn65dsi86-aux";

	pdata->aux.dev = dev;

	pdata->aux.transfer = ti_sn_aux_transfer;

	drm_dp_aux_init(&pdata->aux);



	pdata->bridge.funcs = &ti_sn_bridge_funcs;

	pdata->bridge.of_node = dev->of_node;



	drm_bridge_add(&pdata->bridge);



	return 0;

	}



static int ti_sn65dsi86_remove(struct i2c_client *client)

{

	struct ti_sn65dsi86 *pdata = i2c_get_clientdata(client);



	if (!pdata)

		return -EINVAL;



	if (pdata->dsi) {

		mipi_dsi_detach(pdata->dsi);

		mipi_dsi_device_unregister(pdata->dsi);

	}



	kfree(pdata->edid);



	drm_bridge_remove(&pdata->bridge);



	of_node_put(pdata->host_node);



	return 0;

	return ti_sn65dsi86_add_aux_device(pdata, &pdata->bridge_aux, "bridge");

}



static struct i2c_device_id ti_sn65dsi86_id[] = {
@@ -1348,10 +1461,43 @@ static struct i2c_driver ti_sn65dsi86_driver = { 
		.pm = &ti_sn65dsi86_pm_ops,

	},

	.probe = ti_sn65dsi86_probe,

	.remove = ti_sn65dsi86_remove,

	.id_table = ti_sn65dsi86_id,

};

module_i2c_driver(ti_sn65dsi86_driver);



static int __init ti_sn65dsi86_init(void)

{

	int ret;



	ret = i2c_add_driver(&ti_sn65dsi86_driver);

	if (ret)

		return ret;



	ret = ti_sn_gpio_register();

	if (ret)

		goto err_main_was_registered;



	ret = auxiliary_driver_register(&ti_sn_bridge_driver);

	if (ret)

		goto err_gpio_was_registered;



	return 0;



err_gpio_was_registered:

	ti_sn_gpio_unregister();

err_main_was_registered:

	i2c_del_driver(&ti_sn65dsi86_driver);



	return ret;

}

module_init(ti_sn65dsi86_init);



static void __exit ti_sn65dsi86_exit(void)

{

	auxiliary_driver_unregister(&ti_sn_bridge_driver);

	ti_sn_gpio_unregister();

	i2c_del_driver(&ti_sn65dsi86_driver);

}

module_exit(ti_sn65dsi86_exit);



MODULE_AUTHOR("Sandeep Panda <spanda@codeaurora.org>");

MODULE_DESCRIPTION("sn65dsi86 DSI to eDP bridge driver");