linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v6 0/3] drm: Prepare to use a GPIO on ti-sn65dsi86 for Hot Plug Detect
@ 2020-05-13 21:58 Douglas Anderson
  2020-05-13 21:59 ` [PATCH v6 1/3] drm/bridge: ti-sn65dsi86: Export bridge GPIOs to Linux Douglas Anderson
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Douglas Anderson @ 2020-05-13 21:58 UTC (permalink / raw)
  To: linus.walleij, bgolaszewski, airlied, daniel, robh+dt,
	narmstrong, a.hajda, Laurent.pinchart, spanda
  Cc: bjorn.andersson, dri-devel, swboyd, devicetree, jeffrey.l.hugo,
	jernej.skrabec, linux-arm-msm, robdclark, jonas, linux-gpio,
	Douglas Anderson, Krzysztof Kozlowski, Laurent Pinchart,
	Paul Walmsley, linux-kernel


As talked about in commit c2bfc223882d ("drm/bridge: ti-sn65dsi86:
Remove the mystery delay"), the normal HPD pin on ti-sn65dsi86 is
kinda useless, at least for embedded DisplayPort (eDP).  However,
despite the fact that the actual HPD pin on the bridge is mostly
useless for eDP, the concept of HPD for eDP still makes sense.  It
allows us to optimize out a hardcoded delay that many panels need if
HPD isn't hooked up.  Panel timing diagrams show HPD as one of the
events to measure timing from and we have to assume the worst case if
we can't actually read HPD.

One way to use HPD for eDP without using the mostly useless HPD pin on
ti-sn65dsi86 is to route the panel's HPD somewhere else in the system,
like to a GPIO.  This works great because eDP panels aren't physically
hotplugged.  That means the debouncing logic that caused us problems
wasn't really needed and a raw GPIO works great.

As per the above, a smart board designer would realize the value of
HPD and choose to route it to a GPIO somewhere on the board to avoid
the silly sn65dsi86 debouncing.  While said "smart designer" could
theoretically route HPD anywhere on the board, a really smart designer
would realize that there are several GPIOs on the bridge itself that
are nearly useless for anything but this purpose and route HPD to one
of those.

This series of patches is intended to allow the scenario described
above.

This patch has been tested on a board that is not yet mainline.  On
the hardware I have:
- Panel spec says HPD could take up to 200 ms to come up, so without
  HPD hooked up we need to delay 200 ms.
- On my board the panel is powered by the same rail as the
  touchscreen.  By chance of probe order the touchscreen comes up
  first.  This means by the time we check HPD in ti_sn_bridge_enable()
  it's already up.  Thus we can use the panel on 200 ms earlier.
- If I measure HPD on this pane it comes up ~56 ms after the panel is
  powered.  This means I can save 144 ms of delay.

Side effects (though not main goals) of this series are:
- ti-sn65dsi86 GPIOs are now exported in Linux.
- ti-sn65dsi86 bindings are converted to yaml.
- Common panel bindings now have "hpd-gpios" listed.
- The simple-panel driver in Linux can delay in prepare based on
  "hpd-gpios"
- ti-sn65dsi86 bindings (and current user) now specifies "no-hpd"
  if HPD isn't hooked up.

Patch v6 collects tags that were sent for v5 and does the one
fix that Linus W. requested.  It also drops patches that have
already landed.

Changes in v6:
- pdata->gchip.base = -1

Changes in v5:
- Use of_xlate so that numbers in dts start at 1, not 0.
- Squash https://lore.kernel.org/r/20200506140208.v2.2.I0a2bca02b09c1fcb6b09479b489736d600b3e57f@changeid/

Changes in v4:
- Don't include gpio.h
- Use gpiochip_get_data() instead of container_of() to get data.
- GPIOF_DIR_XXX => GPIO_LINE_DIRECTION_XXX
- Use Linus W's favorite syntax to read a bit from a bitfield.
- Define and use SN_GPIO_MUX_MASK.
- Add a comment about why we use a bitmap for gchip_output.
- Tacked on "or is otherwise unusable." to description.

Changes in v3:
- Becaue => Because
- Add a kernel-doc to our pdata to clarify double-duty of gchip_output.
- More comments about how powering off affects us (get_dir, dir_input).
- Cleanup tail of ti_sn_setup_gpio_controller() to avoid one "return".
- Use a bitmap rather than rolling my own.
- useful implement => useful to implement

Changes in v2:
- ("Export...GPIOs") is 1/2 of replacement for ("Allow...bridge GPIOs")
- specification => specifier.
- power up => power.
- Added back missing suspend-gpios.
- data-lanes and lane-polarities are are the right place now.
- endpoints don't need to be patternProperties.
- Specified more details for data-lanes and lane-polarities.
- Added old example back in, fixing bugs in it.
- Example i2c bus is just called "i2c", not "i2c1" now.
- ("dt-bindings: drm/bridge: ti-sn65dsi86: Document no-hpd") new for v2.

Douglas Anderson (3):
  drm/bridge: ti-sn65dsi86: Export bridge GPIOs to Linux
  dt-bindings: drm/bridge: ti-sn65dsi86: Convert to yaml
  dt-bindings: drm/bridge: ti-sn65dsi86: Document no-hpd

 .../bindings/display/bridge/ti,sn65dsi86.txt  |  87 ------
 .../bindings/display/bridge/ti,sn65dsi86.yaml | 293 ++++++++++++++++++
 drivers/gpu/drm/bridge/ti-sn65dsi86.c         | 215 +++++++++++++
 3 files changed, 508 insertions(+), 87 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.txt
 create mode 100644 Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml

-- 
2.26.2.645.ge9eca65c58-goog


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH v6 1/3] drm/bridge: ti-sn65dsi86: Export bridge GPIOs to Linux
  2020-05-13 21:58 [PATCH v6 0/3] drm: Prepare to use a GPIO on ti-sn65dsi86 for Hot Plug Detect Douglas Anderson
@ 2020-05-13 21:59 ` Douglas Anderson
  2020-05-13 21:59 ` [PATCH v6 2/3] dt-bindings: drm/bridge: ti-sn65dsi86: Convert to yaml Douglas Anderson
  2020-05-13 21:59 ` [PATCH v6 3/3] dt-bindings: drm/bridge: ti-sn65dsi86: Document no-hpd Douglas Anderson
  2 siblings, 0 replies; 6+ messages in thread
From: Douglas Anderson @ 2020-05-13 21:59 UTC (permalink / raw)
  To: linus.walleij, bgolaszewski, airlied, daniel, robh+dt,
	narmstrong, a.hajda, Laurent.pinchart, spanda
  Cc: bjorn.andersson, dri-devel, swboyd, devicetree, jeffrey.l.hugo,
	jernej.skrabec, linux-arm-msm, robdclark, jonas, linux-gpio,
	Douglas Anderson, linux-kernel

The ti-sn65dsi86 MIPI DSI to eDP bridge chip has 4 pins on it that can
be used as GPIOs in a system.  Each pin can be configured as input,
output, or a special function for the bridge chip.  These are:
- GPIO1: SUSPEND Input
- GPIO2: DSIA VSYNC
- GPIO3: DSIA HSYNC or VSYNC
- GPIO4: PWM

Let's expose these pins as GPIOs.  A few notes:
- Access to ti-sn65dsi86 is via i2c so we set "can_sleep".
- These pins can't be configured for IRQ.
- There are no programmable pulls or other fancy features.
- Keeping the bridge chip powered might be expensive.  The driver is
  setup such that if all used GPIOs are only inputs we'll power the
  bridge chip on just long enough to read the GPIO and then power it
  off again.  Setting a GPIO as output will keep the bridge powered.
- If someone releases a GPIO we'll implicitly switch it to an input so
  we no longer need to keep the bridge powered for it.

Because of all of the above limitations we just need to implement a
bare-bones GPIO driver.  The device tree bindings already account for
this device being a GPIO controller so we only need the driver changes
for it.

NOTE: Despite the fact that these pins are nominally muxable I don't
believe it makes sense to expose them through the pinctrl interface as
well as the GPIO interface.  The special functions are things that the
bridge chip driver itself would care about and it can just configure
the pins as needed.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---

Changes in v6:
- pdata->gchip.base = -1

Changes in v5:
- Use of_xlate so that numbers in dts start at 1, not 0.

Changes in v4:
- Don't include gpio.h
- Use gpiochip_get_data() instead of container_of() to get data.
- GPIOF_DIR_XXX => GPIO_LINE_DIRECTION_XXX
- Use Linus W's favorite syntax to read a bit from a bitfield.
- Define and use SN_GPIO_MUX_MASK.
- Add a comment about why we use a bitmap for gchip_output.

Changes in v3:
- Becaue => Because
- Add a kernel-doc to our pdata to clarify double-duty of gchip_output.
- More comments about how powering off affects us (get_dir, dir_input).
- Cleanup tail of ti_sn_setup_gpio_controller() to avoid one "return".
- Use a bitmap rather than rolling my own.

Changes in v2:
- ("Export...GPIOs") is 1/2 of replacement for ("Allow...bridge GPIOs")

 drivers/gpu/drm/bridge/ti-sn65dsi86.c | 215 ++++++++++++++++++++++++++
 1 file changed, 215 insertions(+)

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index 6ad688b320ae..3b91fa0ebdf9 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -4,9 +4,11 @@
  * datasheet: http://www.ti.com/lit/ds/symlink/sn65dsi86.pdf
  */
 
+#include <linux/bits.h>
 #include <linux/clk.h>
 #include <linux/debugfs.h>
 #include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
 #include <linux/i2c.h>
 #include <linux/iopoll.h>
 #include <linux/module.h>
@@ -54,6 +56,14 @@
 #define  BPP_18_RGB				BIT(0)
 #define SN_HPD_DISABLE_REG			0x5C
 #define  HPD_DISABLE				BIT(0)
+#define SN_GPIO_IO_REG				0x5E
+#define  SN_GPIO_INPUT_SHIFT			4
+#define  SN_GPIO_OUTPUT_SHIFT			0
+#define SN_GPIO_CTRL_REG			0x5F
+#define  SN_GPIO_MUX_INPUT			0
+#define  SN_GPIO_MUX_OUTPUT			1
+#define  SN_GPIO_MUX_SPECIAL			2
+#define  SN_GPIO_MUX_MASK			0x3
 #define SN_AUX_WDATA_REG(x)			(0x64 + (x))
 #define SN_AUX_ADDR_19_16_REG			0x74
 #define SN_AUX_ADDR_15_8_REG			0x75
@@ -88,6 +98,35 @@
 
 #define SN_REGULATOR_SUPPLY_NUM		4
 
+#define SN_NUM_GPIOS			4
+#define SN_GPIO_PHYSICAL_OFFSET		1
+
+/**
+ * struct ti_sn_bridge - Platform data for ti-sn65dsi86 driver.
+ * @dev:          Pointer to our device.
+ * @regmap:       Regmap for accessing i2c.
+ * @aux:          Our aux channel.
+ * @bridge:       Our bridge.
+ * @connector:    Our connector.
+ * @debugfs:      Used for managing our debugfs.
+ * @host_node:    Remote DSI node.
+ * @dsi:          Our MIPI DSI source.
+ * @refclk:       Our reference clock.
+ * @panel:        Our panel.
+ * @enable_gpio:  The GPIO we toggle to enable the bridge.
+ * @supplies:     Data for bulk enabling/disabling our regulators.
+ * @dp_lanes:     Count of dp_lanes we're using.
+ *
+ * @gchip:        If we expose our GPIOs, this is used.
+ * @gchip_output: A cache of whether we've set GPIOs to output.  This
+ *                serves double-duty of keeping track of the direction and
+ *                also keeping track of whether we've incremented the
+ *                pm_runtime reference count for this pin, which we do
+ *                whenever a pin is configured as an output.  This is a
+ *                bitmap so we can do atomic ops on it without an extra
+ *                lock so concurrent users of our 4 GPIOs don't stomp on
+ *                each other's read-modify-write.
+ */
 struct ti_sn_bridge {
 	struct device			*dev;
 	struct regmap			*regmap;
@@ -102,6 +141,9 @@ struct ti_sn_bridge {
 	struct gpio_desc		*enable_gpio;
 	struct regulator_bulk_data	supplies[SN_REGULATOR_SUPPLY_NUM];
 	int				dp_lanes;
+
+	struct gpio_chip		gchip;
+	DECLARE_BITMAP(gchip_output, SN_NUM_GPIOS);
 };
 
 static const struct regmap_range ti_sn_bridge_volatile_ranges[] = {
@@ -874,6 +916,173 @@ static int ti_sn_bridge_parse_dsi_host(struct ti_sn_bridge *pdata)
 	return 0;
 }
 
+static int tn_sn_bridge_of_xlate(struct gpio_chip *chip,
+				 const struct of_phandle_args *gpiospec,
+				 u32 *flags)
+{
+	if (WARN_ON(gpiospec->args_count < chip->of_gpio_n_cells))
+		return -EINVAL;
+
+	if (gpiospec->args[0] > chip->ngpio || gpiospec->args[0] < 1)
+		return -EINVAL;
+
+	if (flags)
+		*flags = gpiospec->args[1];
+
+	return gpiospec->args[0] - SN_GPIO_PHYSICAL_OFFSET;
+}
+
+static int ti_sn_bridge_gpio_get_direction(struct gpio_chip *chip,
+					   unsigned int offset)
+{
+	struct ti_sn_bridge *pdata = gpiochip_get_data(chip);
+
+	/*
+	 * We already have to keep track of the direction because we use
+	 * that to figure out whether we've powered the device.  We can
+	 * just return that rather than (maybe) powering up the device
+	 * to ask its direction.
+	 */
+	return test_bit(offset, pdata->gchip_output) ?
+		GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN;
+}
+
+static int ti_sn_bridge_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	struct ti_sn_bridge *pdata = gpiochip_get_data(chip);
+	unsigned int val;
+	int ret;
+
+	/*
+	 * When the pin is an input we don't forcibly keep the bridge
+	 * powered--we just power it on to read the pin.  NOTE: part of
+	 * the reason this works is that the bridge defaults (when
+	 * powered back on) to all 4 GPIOs being configured as GPIO input.
+	 * Also note that if something else is keeping the chip powered the
+	 * pm_runtime functions are lightweight increments of a refcount.
+	 */
+	pm_runtime_get_sync(pdata->dev);
+	ret = regmap_read(pdata->regmap, SN_GPIO_IO_REG, &val);
+	pm_runtime_put(pdata->dev);
+
+	if (ret)
+		return ret;
+
+	return !!(val & BIT(SN_GPIO_INPUT_SHIFT + offset));
+}
+
+static void ti_sn_bridge_gpio_set(struct gpio_chip *chip, unsigned int offset,
+				  int val)
+{
+	struct ti_sn_bridge *pdata = gpiochip_get_data(chip);
+	int ret;
+
+	if (!test_bit(offset, pdata->gchip_output)) {
+		dev_err(pdata->dev, "Ignoring GPIO set while input\n");
+		return;
+	}
+
+	val &= 1;
+	ret = regmap_update_bits(pdata->regmap, SN_GPIO_IO_REG,
+				 BIT(SN_GPIO_OUTPUT_SHIFT + offset),
+				 val << (SN_GPIO_OUTPUT_SHIFT + offset));
+}
+
+static int ti_sn_bridge_gpio_direction_input(struct gpio_chip *chip,
+					     unsigned int offset)
+{
+	struct ti_sn_bridge *pdata = gpiochip_get_data(chip);
+	int shift = offset * 2;
+	int ret;
+
+	if (!test_and_clear_bit(offset, pdata->gchip_output))
+		return 0;
+
+	ret = regmap_update_bits(pdata->regmap, SN_GPIO_CTRL_REG,
+				 SN_GPIO_MUX_MASK << shift,
+				 SN_GPIO_MUX_INPUT << shift);
+	if (ret) {
+		set_bit(offset, pdata->gchip_output);
+		return ret;
+	}
+
+	/*
+	 * NOTE: if nobody else is powering the device this may fully power
+	 * it off and when it comes back it will have lost all state, but
+	 * that's OK because the default is input and we're now an input.
+	 */
+	pm_runtime_put(pdata->dev);
+
+	return 0;
+}
+
+static int ti_sn_bridge_gpio_direction_output(struct gpio_chip *chip,
+					      unsigned int offset, int val)
+{
+	struct ti_sn_bridge *pdata = gpiochip_get_data(chip);
+	int shift = offset * 2;
+	int ret;
+
+	if (test_and_set_bit(offset, pdata->gchip_output))
+		return 0;
+
+	pm_runtime_get_sync(pdata->dev);
+
+	/* Set value first to avoid glitching */
+	ti_sn_bridge_gpio_set(chip, offset, val);
+
+	/* Set direction */
+	ret = regmap_update_bits(pdata->regmap, SN_GPIO_CTRL_REG,
+				 SN_GPIO_MUX_MASK << shift,
+				 SN_GPIO_MUX_OUTPUT << shift);
+	if (ret) {
+		clear_bit(offset, pdata->gchip_output);
+		pm_runtime_put(pdata->dev);
+	}
+
+	return ret;
+}
+
+static void ti_sn_bridge_gpio_free(struct gpio_chip *chip, unsigned int offset)
+{
+	/* We won't keep pm_runtime if we're input, so switch there on free */
+	ti_sn_bridge_gpio_direction_input(chip, offset);
+}
+
+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_sn_bridge *pdata)
+{
+	int ret;
+
+	/* Only init if someone is going to use us as a GPIO controller */
+	if (!of_property_read_bool(pdata->dev->of_node, "gpio-controller"))
+		return 0;
+
+	pdata->gchip.label = dev_name(pdata->dev);
+	pdata->gchip.parent = pdata->dev;
+	pdata->gchip.owner = THIS_MODULE;
+	pdata->gchip.of_xlate = tn_sn_bridge_of_xlate;
+	pdata->gchip.of_gpio_n_cells = 2;
+	pdata->gchip.free = ti_sn_bridge_gpio_free;
+	pdata->gchip.get_direction = ti_sn_bridge_gpio_get_direction;
+	pdata->gchip.direction_input = ti_sn_bridge_gpio_direction_input;
+	pdata->gchip.direction_output = ti_sn_bridge_gpio_direction_output;
+	pdata->gchip.get = ti_sn_bridge_gpio_get;
+	pdata->gchip.set = ti_sn_bridge_gpio_set;
+	pdata->gchip.can_sleep = true;
+	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);
+	if (ret)
+		dev_err(pdata->dev, "can't add gpio chip\n");
+
+	return ret;
+}
+
 static int ti_sn_bridge_probe(struct i2c_client *client,
 			      const struct i2c_device_id *id)
 {
@@ -937,6 +1146,12 @@ static int ti_sn_bridge_probe(struct i2c_client *client,
 
 	pm_runtime_enable(pdata->dev);
 
+	ret = ti_sn_setup_gpio_controller(pdata);
+	if (ret) {
+		pm_runtime_disable(pdata->dev);
+		return ret;
+	}
+
 	i2c_set_clientdata(client, pdata);
 
 	pdata->aux.name = "ti-sn65dsi86-aux";
-- 
2.26.2.645.ge9eca65c58-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v6 2/3] dt-bindings: drm/bridge: ti-sn65dsi86: Convert to yaml
  2020-05-13 21:58 [PATCH v6 0/3] drm: Prepare to use a GPIO on ti-sn65dsi86 for Hot Plug Detect Douglas Anderson
  2020-05-13 21:59 ` [PATCH v6 1/3] drm/bridge: ti-sn65dsi86: Export bridge GPIOs to Linux Douglas Anderson
@ 2020-05-13 21:59 ` Douglas Anderson
  2020-05-26 22:08   ` Rob Herring
  2020-05-13 21:59 ` [PATCH v6 3/3] dt-bindings: drm/bridge: ti-sn65dsi86: Document no-hpd Douglas Anderson
  2 siblings, 1 reply; 6+ messages in thread
From: Douglas Anderson @ 2020-05-13 21:59 UTC (permalink / raw)
  To: linus.walleij, bgolaszewski, airlied, daniel, robh+dt,
	narmstrong, a.hajda, Laurent.pinchart, spanda
  Cc: bjorn.andersson, dri-devel, swboyd, devicetree, jeffrey.l.hugo,
	jernej.skrabec, linux-arm-msm, robdclark, jonas, linux-gpio,
	Douglas Anderson, Krzysztof Kozlowski, Laurent Pinchart,
	Paul Walmsley, linux-kernel

This moves the bindings over, based a lot on toshiba,tc358768.yaml.
Unless there's someone known to be better, I've set the maintainer in
the yaml as the first person to submit bindings.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
---
I removed Stephen's review tag on v5 since I squashed in a bunch of
other stuff.

Changes in v6: None
Changes in v5:
- Squash https://lore.kernel.org/r/20200506140208.v2.2.I0a2bca02b09c1fcb6b09479b489736d600b3e57f@changeid/

Changes in v4: None
Changes in v3: None
Changes in v2:
- specification => specifier.
- power up => power.
- Added back missing suspend-gpios.
- data-lanes and lane-polarities are are the right place now.
- endpoints don't need to be patternProperties.
- Specified more details for data-lanes and lane-polarities.
- Added old example back in, fixing bugs in it.
- Example i2c bus is just called "i2c", not "i2c1" now.

 .../bindings/display/bridge/ti,sn65dsi86.txt  |  87 ------
 .../bindings/display/bridge/ti,sn65dsi86.yaml | 285 ++++++++++++++++++
 2 files changed, 285 insertions(+), 87 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.txt
 create mode 100644 Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml

diff --git a/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.txt b/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.txt
deleted file mode 100644
index 8ec4a7f2623a..000000000000
--- a/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.txt
+++ /dev/null
@@ -1,87 +0,0 @@
-SN65DSI86 DSI to eDP bridge chip
---------------------------------
-
-This is the binding for Texas Instruments SN65DSI86 bridge.
-http://www.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=sn65dsi86&fileType=pdf
-
-Required properties:
-- compatible: Must be "ti,sn65dsi86"
-- reg: i2c address of the chip, 0x2d as per datasheet
-- enable-gpios: gpio specification for bridge_en pin (active high)
-
-- vccio-supply: A 1.8V supply that powers up the digital IOs.
-- vpll-supply: A 1.8V supply that powers up the displayport PLL.
-- vcca-supply: A 1.2V supply that powers up the analog circuits.
-- vcc-supply: A 1.2V supply that powers up the digital core.
-
-Optional properties:
-- interrupts-extended: Specifier for the SN65DSI86 interrupt line.
-
-- gpio-controller: Marks the device has a GPIO controller.
-- #gpio-cells    : Should be two. The first cell is the pin number and
-                   the second cell is used to specify flags.
-                   See ../../gpio/gpio.txt for more information.
-- #pwm-cells : Should be one. See ../../pwm/pwm.yaml for description of
-               the cell formats.
-
-- clock-names: should be "refclk"
-- clocks: Specification for input reference clock. The reference
-	  clock rate must be 12 MHz, 19.2 MHz, 26 MHz, 27 MHz or 38.4 MHz.
-
-- data-lanes: See ../../media/video-interface.txt
-- lane-polarities: See ../../media/video-interface.txt
-
-- suspend-gpios: specification for GPIO1 pin on bridge (active low)
-
-Required nodes:
-This device has two video ports. Their connections are modelled using the
-OF graph bindings specified in Documentation/devicetree/bindings/graph.txt.
-
-- Video port 0 for DSI input
-- Video port 1 for eDP output
-
-Example
--------
-
-edp-bridge@2d {
-	compatible = "ti,sn65dsi86";
-	#address-cells = <1>;
-	#size-cells = <0>;
-	reg = <0x2d>;
-
-	enable-gpios = <&msmgpio 33 GPIO_ACTIVE_HIGH>;
-	suspend-gpios = <&msmgpio 34 GPIO_ACTIVE_LOW>;
-
-	interrupts-extended = <&gpio3 4 IRQ_TYPE_EDGE_FALLING>;
-
-	vccio-supply = <&pm8916_l17>;
-	vcca-supply = <&pm8916_l6>;
-	vpll-supply = <&pm8916_l17>;
-	vcc-supply = <&pm8916_l6>;
-
-	clock-names = "refclk";
-	clocks = <&input_refclk>;
-
-	ports {
-		#address-cells = <1>;
-		#size-cells = <0>;
-
-		port@0 {
-			reg = <0>;
-
-			edp_bridge_in: endpoint {
-				remote-endpoint = <&dsi_out>;
-			};
-		};
-
-		port@1 {
-			reg = <1>;
-
-			edp_bridge_out: endpoint {
-				data-lanes = <2 1 3 0>;
-				lane-polarities = <0 1 0 1>;
-				remote-endpoint = <&edp_panel_in>;
-			};
-		};
-	};
-}
diff --git a/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml b/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml
new file mode 100644
index 000000000000..07d26121afca
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml
@@ -0,0 +1,285 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/bridge/ti,sn65dsi86.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SN65DSI86 DSI to eDP bridge chip
+
+maintainers:
+  - Sandeep Panda <spanda@codeaurora.org>
+
+description: |
+  The Texas Instruments SN65DSI86 bridge takes MIPI DSI in and outputs eDP.
+  http://www.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=sn65dsi86&fileType=pdf
+
+properties:
+  compatible:
+    const: ti,sn65dsi86
+
+  reg:
+    const: 0x2d
+
+  enable-gpios:
+    maxItems: 1
+    description: GPIO specifier for bridge_en pin (active high).
+
+  suspend-gpios:
+    maxItems: 1
+    description: GPIO specifier for GPIO1 pin on bridge (active low).
+
+  vccio-supply:
+    description: A 1.8V supply that powers the digital IOs.
+
+  vpll-supply:
+    description: A 1.8V supply that powers the DisplayPort PLL.
+
+  vcca-supply:
+    description: A 1.2V supply that powers the analog circuits.
+
+  vcc-supply:
+    description: A 1.2V supply that powers the digital core.
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+    description:
+      Clock specifier for input reference clock. The reference clock rate must
+      be 12 MHz, 19.2 MHz, 26 MHz, 27 MHz or 38.4 MHz.
+
+  clock-names:
+    const: refclk
+
+  gpio-controller: true
+  '#gpio-cells':
+    const: 2
+    description:
+      First cell is pin number, second cell is flags.  GPIO pin numbers are
+      1-based to match the datasheet.  See ../../gpio/gpio.txt for more
+      information.
+
+  '#pwm-cells':
+    const: 1
+    description: See ../../pwm/pwm.yaml for description of the cell formats.
+
+  ports:
+    type: object
+    additionalProperties: false
+
+    properties:
+      "#address-cells":
+        const: 1
+
+      "#size-cells":
+        const: 0
+
+      port@0:
+        type: object
+        additionalProperties: false
+
+        description:
+          Video port for MIPI DSI input
+
+        properties:
+          reg:
+            const: 0
+
+          endpoint:
+            type: object
+            additionalProperties: false
+            properties:
+              remote-endpoint: true
+
+        required:
+          - reg
+
+      port@1:
+        type: object
+        additionalProperties: false
+
+        description:
+          Video port for eDP output (panel or connector).
+
+        properties:
+          reg:
+            const: 1
+
+          endpoint:
+            type: object
+            additionalProperties: false
+
+            properties:
+              remote-endpoint: true
+
+              data-lanes:
+                oneOf:
+                  - minItems: 1
+                    maxItems: 1
+                    uniqueItems: true
+                    items:
+                      enum:
+                        - 0
+                        - 1
+                    description:
+                      If you have 1 logical lane the bridge supports routing
+                      to either port 0 or port 1.  Port 0 is suggested.
+                      See ../../media/video-interface.txt for details.
+
+                  - minItems: 2
+                    maxItems: 2
+                    uniqueItems: true
+                    items:
+                      enum:
+                        - 0
+                        - 1
+                    description:
+                      If you have 2 logical lanes the bridge supports
+                      reordering but only on physical ports 0 and 1.
+                      See ../../media/video-interface.txt for details.
+
+                  - minItems: 4
+                    maxItems: 4
+                    uniqueItems: true
+                    items:
+                      enum:
+                        - 0
+                        - 1
+                        - 2
+                        - 3
+                    description:
+                      If you have 4 logical lanes the bridge supports
+                      reordering in any way.
+                      See ../../media/video-interface.txt for details.
+
+              lane-polarities:
+                minItems: 1
+                maxItems: 4
+                items:
+                  enum:
+                    - 0
+                    - 1
+                description: See ../../media/video-interface.txt
+
+            dependencies:
+              lane-polarities: [data-lanes]
+
+        required:
+          - reg
+
+    required:
+      - "#address-cells"
+      - "#size-cells"
+      - port@0
+      - port@1
+
+required:
+  - compatible
+  - reg
+  - enable-gpios
+  - vccio-supply
+  - vpll-supply
+  - vcca-supply
+  - vcc-supply
+  - ports
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/qcom,rpmh.h>
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      bridge@2d {
+        compatible = "ti,sn65dsi86";
+        reg = <0x2d>;
+
+        interrupt-parent = <&tlmm>;
+        interrupts = <10 IRQ_TYPE_LEVEL_HIGH>;
+
+        enable-gpios = <&tlmm 102 GPIO_ACTIVE_HIGH>;
+
+        vpll-supply = <&src_pp1800_s4a>;
+        vccio-supply = <&src_pp1800_s4a>;
+        vcca-supply = <&src_pp1200_l2a>;
+        vcc-supply = <&src_pp1200_l2a>;
+
+        clocks = <&rpmhcc RPMH_LN_BB_CLK2>;
+        clock-names = "refclk";
+
+        ports {
+          #address-cells = <1>;
+          #size-cells = <0>;
+
+          port@0 {
+            reg = <0>;
+            endpoint {
+              remote-endpoint = <&dsi0_out>;
+            };
+          };
+
+          port@1 {
+            reg = <1>;
+            endpoint {
+              remote-endpoint = <&panel_in_edp>;
+            };
+          };
+        };
+      };
+    };
+  - |
+    #include <dt-bindings/clock/qcom,rpmh.h>
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      bridge@2d {
+        compatible = "ti,sn65dsi86";
+        reg = <0x2d>;
+
+        enable-gpios = <&msmgpio 33 GPIO_ACTIVE_HIGH>;
+        suspend-gpios = <&msmgpio 34 GPIO_ACTIVE_LOW>;
+
+        interrupts-extended = <&gpio3 4 IRQ_TYPE_EDGE_FALLING>;
+
+        vccio-supply = <&pm8916_l17>;
+        vcca-supply = <&pm8916_l6>;
+        vpll-supply = <&pm8916_l17>;
+        vcc-supply = <&pm8916_l6>;
+
+        clock-names = "refclk";
+        clocks = <&input_refclk>;
+
+        ports {
+          #address-cells = <1>;
+          #size-cells = <0>;
+
+          port@0 {
+            reg = <0>;
+
+            edp_bridge_in: endpoint {
+              remote-endpoint = <&dsi_out>;
+            };
+          };
+
+          port@1 {
+            reg = <1>;
+
+            edp_bridge_out: endpoint {
+              data-lanes = <2 1 3 0>;
+              lane-polarities = <0 1 0 1>;
+              remote-endpoint = <&edp_panel_in>;
+            };
+          };
+        };
+      };
+    };
-- 
2.26.2.645.ge9eca65c58-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v6 3/3] dt-bindings: drm/bridge: ti-sn65dsi86: Document no-hpd
  2020-05-13 21:58 [PATCH v6 0/3] drm: Prepare to use a GPIO on ti-sn65dsi86 for Hot Plug Detect Douglas Anderson
  2020-05-13 21:59 ` [PATCH v6 1/3] drm/bridge: ti-sn65dsi86: Export bridge GPIOs to Linux Douglas Anderson
  2020-05-13 21:59 ` [PATCH v6 2/3] dt-bindings: drm/bridge: ti-sn65dsi86: Convert to yaml Douglas Anderson
@ 2020-05-13 21:59 ` Douglas Anderson
  2020-05-26 22:22   ` Rob Herring
  2 siblings, 1 reply; 6+ messages in thread
From: Douglas Anderson @ 2020-05-13 21:59 UTC (permalink / raw)
  To: linus.walleij, bgolaszewski, airlied, daniel, robh+dt,
	narmstrong, a.hajda, Laurent.pinchart, spanda
  Cc: bjorn.andersson, dri-devel, swboyd, devicetree, jeffrey.l.hugo,
	jernej.skrabec, linux-arm-msm, robdclark, jonas, linux-gpio,
	Douglas Anderson, Laurent Pinchart, linux-kernel

The ti-sn65dsi86 MIPI DSI to eDP bridge chip has a dedicated hardware
HPD (Hot Plug Detect) pin on it, but it's mostly useless for eDP
because of excessive debouncing in hardware.  Specifically there is no
way to disable the debouncing and for eDP debouncing hurts you because
HPD is just used for knowing when the panel is ready, not for
detecting physical plug events.

Currently the driver in Linux just assumes that nobody has HPD hooked
up.  It relies on folks setting the "no-hpd" property in the panel
node to specify that HPD isn't hooked up and then the panel driver
using this to add some worst case delays when turning on the panel.

Apparently it's also useful to specify "no-hpd" in the bridge node so
that the bridge driver can make sure it's doing the right thing
without peeking into the panel [1].  This would be used if anyone ever
found it useful to implement support for the HW HPD pin on the bridge.
Let's add this property to the bindings.

NOTES:
- This is somewhat of a backward-incompatible change.  All current
  known users of ti-sn65dsi86 didn't have "no-hpd" specified in the
  bridge node yet none of them had HPD hooked up.  This worked because
  the current Linux driver just assumed that HPD was never hooked up.
  We could make it less incompatible by saying that for this bridge
  it's assumed HPD isn't hooked up _unless_ a property is defined, but
  "no-hpd" is much more standard and it's unlikely to matter unless
  someone quickly goes and implements HPD in the driver.
- It is sensible to specify "no-hpd" at the bridge chip level and
  specify "hpd-gpios" at the panel level.  That would mean HPD is
  hooked up to some other GPIO in the system, just not the hardware
  HPD pin on the bridge chip.

[1] https://lore.kernel.org/r/20200417180819.GE5861@pendragon.ideasonboard.com

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---

Changes in v6: None
Changes in v5: None
Changes in v4:
- Tacked on "or is otherwise unusable." to description.

Changes in v3:
- useful implement => useful to implement

Changes in v2:
- ("dt-bindings: drm/bridge: ti-sn65dsi86: Document no-hpd") new for v2.

 .../devicetree/bindings/display/bridge/ti,sn65dsi86.yaml  | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml b/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml
index 07d26121afca..be10e8cf31e1 100644
--- a/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml
+++ b/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml
@@ -28,6 +28,12 @@ properties:
     maxItems: 1
     description: GPIO specifier for GPIO1 pin on bridge (active low).
 
+  no-hpd:
+    type: boolean
+    description:
+      Set if the HPD line on the bridge isn't hooked up to anything or is
+      otherwise unusable.
+
   vccio-supply:
     description: A 1.8V supply that powers the digital IOs.
 
@@ -213,6 +219,8 @@ examples:
         clocks = <&rpmhcc RPMH_LN_BB_CLK2>;
         clock-names = "refclk";
 
+        no-hpd;
+
         ports {
           #address-cells = <1>;
           #size-cells = <0>;
-- 
2.26.2.645.ge9eca65c58-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH v6 2/3] dt-bindings: drm/bridge: ti-sn65dsi86: Convert to yaml
  2020-05-13 21:59 ` [PATCH v6 2/3] dt-bindings: drm/bridge: ti-sn65dsi86: Convert to yaml Douglas Anderson
@ 2020-05-26 22:08   ` Rob Herring
  0 siblings, 0 replies; 6+ messages in thread
From: Rob Herring @ 2020-05-26 22:08 UTC (permalink / raw)
  To: Douglas Anderson
  Cc: daniel, linux-arm-msm, jonas, linus.walleij, devicetree,
	dri-devel, robh+dt, Paul Walmsley, a.hajda, narmstrong,
	Laurent Pinchart, linux-gpio, Krzysztof Kozlowski, robdclark,
	jeffrey.l.hugo, jernej.skrabec, airlied, spanda,
	Laurent.pinchart, swboyd, bgolaszewski, bjorn.andersson,
	linux-kernel

On Wed, 13 May 2020 14:59:01 -0700, Douglas Anderson wrote:
> This moves the bindings over, based a lot on toshiba,tc358768.yaml.
> Unless there's someone known to be better, I've set the maintainer in
> the yaml as the first person to submit bindings.
> 
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> ---
> I removed Stephen's review tag on v5 since I squashed in a bunch of
> other stuff.
> 
> Changes in v6: None
> Changes in v5:
> - Squash https://lore.kernel.org/r/20200506140208.v2.2.I0a2bca02b09c1fcb6b09479b489736d600b3e57f@changeid/
> 
> Changes in v4: None
> Changes in v3: None
> Changes in v2:
> - specification => specifier.
> - power up => power.
> - Added back missing suspend-gpios.
> - data-lanes and lane-polarities are are the right place now.
> - endpoints don't need to be patternProperties.
> - Specified more details for data-lanes and lane-polarities.
> - Added old example back in, fixing bugs in it.
> - Example i2c bus is just called "i2c", not "i2c1" now.
> 
>  .../bindings/display/bridge/ti,sn65dsi86.txt  |  87 ------
>  .../bindings/display/bridge/ti,sn65dsi86.yaml | 285 ++++++++++++++++++
>  2 files changed, 285 insertions(+), 87 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.txt
>  create mode 100644 Documentation/devicetree/bindings/display/bridge/ti,sn65dsi86.yaml
> 

Reviewed-by: Rob Herring <robh@kernel.org>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v6 3/3] dt-bindings: drm/bridge: ti-sn65dsi86: Document no-hpd
  2020-05-13 21:59 ` [PATCH v6 3/3] dt-bindings: drm/bridge: ti-sn65dsi86: Document no-hpd Douglas Anderson
@ 2020-05-26 22:22   ` Rob Herring
  0 siblings, 0 replies; 6+ messages in thread
From: Rob Herring @ 2020-05-26 22:22 UTC (permalink / raw)
  To: Douglas Anderson
  Cc: linus.walleij, bgolaszewski, airlied, daniel, narmstrong,
	a.hajda, Laurent.pinchart, spanda, bjorn.andersson, dri-devel,
	swboyd, devicetree, jeffrey.l.hugo, jernej.skrabec,
	linux-arm-msm, robdclark, jonas, linux-gpio, linux-kernel

On Wed, May 13, 2020 at 02:59:02PM -0700, Douglas Anderson wrote:
> The ti-sn65dsi86 MIPI DSI to eDP bridge chip has a dedicated hardware
> HPD (Hot Plug Detect) pin on it, but it's mostly useless for eDP
> because of excessive debouncing in hardware.  Specifically there is no
> way to disable the debouncing and for eDP debouncing hurts you because
> HPD is just used for knowing when the panel is ready, not for
> detecting physical plug events.
> 
> Currently the driver in Linux just assumes that nobody has HPD hooked
> up.  It relies on folks setting the "no-hpd" property in the panel
> node to specify that HPD isn't hooked up and then the panel driver
> using this to add some worst case delays when turning on the panel.
> 
> Apparently it's also useful to specify "no-hpd" in the bridge node so
> that the bridge driver can make sure it's doing the right thing
> without peeking into the panel [1].  This would be used if anyone ever
> found it useful to implement support for the HW HPD pin on the bridge.
> Let's add this property to the bindings.
> 
> NOTES:
> - This is somewhat of a backward-incompatible change.  All current
>   known users of ti-sn65dsi86 didn't have "no-hpd" specified in the
>   bridge node yet none of them had HPD hooked up.  This worked because
>   the current Linux driver just assumed that HPD was never hooked up.
>   We could make it less incompatible by saying that for this bridge
>   it's assumed HPD isn't hooked up _unless_ a property is defined, but
>   "no-hpd" is much more standard and it's unlikely to matter unless
>   someone quickly goes and implements HPD in the driver.
> - It is sensible to specify "no-hpd" at the bridge chip level and
>   specify "hpd-gpios" at the panel level.  That would mean HPD is
>   hooked up to some other GPIO in the system, just not the hardware
>   HPD pin on the bridge chip.

I would say 'no-hpd' belongs wherever HPD is broken. So it may still 
make sense in the panel. (Otherwise, it needs to be removed from 
panel-common.yaml and some panel bindings, right?)
 
> [1] https://lore.kernel.org/r/20200417180819.GE5861@pendragon.ideasonboard.com
> 
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---

In any case,

Reviewed-by: Rob Herring <robh@kernel.org>

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2020-05-26 22:22 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-13 21:58 [PATCH v6 0/3] drm: Prepare to use a GPIO on ti-sn65dsi86 for Hot Plug Detect Douglas Anderson
2020-05-13 21:59 ` [PATCH v6 1/3] drm/bridge: ti-sn65dsi86: Export bridge GPIOs to Linux Douglas Anderson
2020-05-13 21:59 ` [PATCH v6 2/3] dt-bindings: drm/bridge: ti-sn65dsi86: Convert to yaml Douglas Anderson
2020-05-26 22:08   ` Rob Herring
2020-05-13 21:59 ` [PATCH v6 3/3] dt-bindings: drm/bridge: ti-sn65dsi86: Document no-hpd Douglas Anderson
2020-05-26 22:22   ` Rob Herring

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).