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Subject[PATCH v3 2/2] drm/bridge: tc358767: Expose test mode functionality via debugfs
Date
Presently, the driver code artificially limits test pattern mode to a
single pattern with fixed color selection. It being a kernel module
parameter makes switching "test pattern" <-> "proper output" modes
on-the-fly clunky and outright impossible if the driver is built into
the kernel.

To improve the situation a bit, convert current test pattern code to
use debugfs instead by exposing "TestCtl" register. This way old
"tc_test_pattern=1" functionality can be emulated via:

echo -n 0x78146302 > tstctl

and switch back to regular mode can be done with:

echo -n 0x78146300 > tstctl

Note that switching to any of the test patterns, will NOT trigger link
re-establishment whereas switching to normal operation WILL. This is
done so:

a) we can isolate and verify (e)DP link functionality by switching to
one of the test patters

b) trigger a link re-establishment by switching back to normal mode

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
---
drivers/gpu/drm/bridge/tc358767.c | 152 ++++++++++++++++++++++++------
1 file changed, 125 insertions(+), 27 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index 3c252ae0ee6f..12a8829e0ed1 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -17,6 +17,7 @@

#include <linux/bitfield.h>
#include <linux/clk.h>
+#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
@@ -221,11 +222,10 @@
#define COLOR_B GENMASK(15, 8)
#define ENI2CFILTER BIT(4)
#define COLOR_BAR_MODE GENMASK(1, 0)
+#define COLOR_BAR_MODE_NORMAL 0
#define COLOR_BAR_MODE_BARS 2
-#define PLL_DBG 0x0a04

-static bool tc_test_pattern;
-module_param_named(test, tc_test_pattern, bool, 0644);
+#define PLL_DBG 0x0a04

struct tc_edp_link {
struct drm_dp_link base;
@@ -263,6 +263,9 @@ struct tc_data {

/* HPD pin number (0 or 1) or -ENODEV */
int hpd_pin;
+
+ struct mutex tstctl_lock;
+ bool enabled;
};

static inline struct tc_data *aux_to_tc(struct drm_dp_aux *a)
@@ -791,16 +794,6 @@ static int tc_set_video_mode(struct tc_data *tc,
if (ret)
return ret;

- /* Test pattern settings */
- ret = regmap_write(tc->regmap, TSTCTL,
- FIELD_PREP(COLOR_R, 120) |
- FIELD_PREP(COLOR_G, 20) |
- FIELD_PREP(COLOR_B, 99) |
- ENI2CFILTER |
- FIELD_PREP(COLOR_BAR_MODE, COLOR_BAR_MODE_BARS));
- if (ret)
- return ret;
-
/* DP Main Stream Attributes */
vid_sync_dly = hsync_len + left_margin + mode->hdisplay;
ret = regmap_write(tc->regmap, DP0_VIDSYNCDELAY,
@@ -1152,14 +1145,6 @@ static int tc_stream_enable(struct tc_data *tc)

dev_dbg(tc->dev, "enable video stream\n");

- /* PXL PLL setup */
- if (tc_test_pattern) {
- ret = tc_pxl_pll_en(tc, clk_get_rate(tc->refclk),
- 1000 * tc->mode.clock);
- if (ret)
- return ret;
- }
-
ret = tc_set_video_mode(tc, &tc->mode);
if (ret)
return ret;
@@ -1188,12 +1173,8 @@ static int tc_stream_enable(struct tc_data *tc)
if (ret)
return ret;
/* Set input interface */
- value = DP0_AUDSRC_NO_INPUT;
- if (tc_test_pattern)
- value |= DP0_VIDSRC_COLOR_BAR;
- else
- value |= DP0_VIDSRC_DPI_RX;
- ret = regmap_write(tc->regmap, SYSCTRL, value);
+ ret = regmap_write(tc->regmap, SYSCTRL,
+ DP0_AUDSRC_NO_INPUT | DP0_VIDSRC_DPI_RX);
if (ret)
return ret;

@@ -1252,8 +1233,13 @@ static void tc_bridge_enable(struct drm_bridge *bridge)
{
struct tc_data *tc = bridge_to_tc(bridge);

+ mutex_lock(&tc->tstctl_lock);
+
if (!__tc_bridge_enable(tc))
drm_panel_enable(tc->panel);
+
+ tc->enabled = true;
+ mutex_unlock(&tc->tstctl_lock);
}

static int __tc_bridge_disable(struct tc_data *tc)
@@ -1275,8 +1261,13 @@ static void tc_bridge_disable(struct drm_bridge *bridge)
{
struct tc_data *tc = bridge_to_tc(bridge);

+ mutex_lock(&tc->tstctl_lock);
+
drm_panel_disable(tc->panel);
__tc_bridge_disable(tc);
+
+ tc->enabled = false;
+ mutex_unlock(&tc->tstctl_lock);
}

static void tc_bridge_post_disable(struct drm_bridge *bridge)
@@ -1388,6 +1379,99 @@ static enum drm_connector_status tc_connector_detect(struct drm_connector *conne
return connector_status_disconnected;
}

+static int tc_tstctl_set(void *data, u64 val)
+{
+ struct tc_data *tc = data;
+ int ret;
+
+ mutex_lock(&tc->tstctl_lock);
+
+ if (!tc->enabled) {
+ dev_err(tc->dev, "bridge needs to be enabled first\n");
+ ret = -EBUSY;
+ goto unlock;
+ }
+
+ if (FIELD_GET(COLOR_BAR_MODE, val) == COLOR_BAR_MODE_NORMAL) {
+ ret = regmap_write(tc->regmap, SYSCTRL, DP0_VIDSRC_DPI_RX);
+ if (ret) {
+ dev_err(tc->dev,
+ "failed to select dpi video stream\n");
+ goto unlock;
+ }
+
+ ret = regmap_write(tc->regmap, TSTCTL, val | ENI2CFILTER);
+ if (ret) {
+ dev_err(tc->dev, "failed to set TSTCTL\n");
+ goto unlock;
+ }
+
+ ret = tc_pxl_pll_dis(tc);
+ if (ret) {
+ dev_err(tc->dev, "failed to disable PLL\n");
+ goto unlock;
+ }
+
+ /*
+ * Re-establish DP link
+ */
+ ret = __tc_bridge_disable(tc);
+ if (ret)
+ goto unlock;
+
+ ret = __tc_bridge_enable(tc);
+ if (ret)
+ goto unlock;
+ } else {
+ ret = tc_pxl_pll_en(tc, clk_get_rate(tc->refclk),
+ 1000 * tc->mode.clock);
+ if (ret) {
+ dev_err(tc->dev, "failed to enable PLL\n");
+ goto unlock;
+ }
+
+ ret = regmap_write(tc->regmap, TSTCTL, val | ENI2CFILTER);
+ if (ret) {
+ dev_err(tc->dev, "failed to set TSTCTL\n");
+ goto unlock;
+ }
+
+ ret = regmap_write(tc->regmap, SYSCTRL, DP0_VIDSRC_COLOR_BAR);
+ if (ret) {
+ dev_err(tc->dev, "failed to set SYSCTRL\n");
+ goto unlock;
+ }
+ }
+
+unlock:
+ mutex_unlock(&tc->tstctl_lock);
+ return ret;
+}
+/*
+ * "tstctl" attribute has the following format:
+ *
+ * RR_GG_BB_0_P
+ *
+ * "RR" is red, "GG" is green and "BB" is blue color components (byte
+ * each) used for various test patterns controlled by this register.
+ *
+ * "P" represents test pattern of the bridge. Valid values are:
+ *
+ * "0" - normal operation
+ * "1" - solid color test pattern
+ * "2" - color bar test pattern
+ * "3" - "checkers" test pattern
+ *
+ * This way old "tc_test_pattern=1" functionality can be emulated via:
+ *
+ * echo -n 0x78146302 > tstctl
+ *
+ * and switch back to regular mode can be done with:
+ *
+ * echo -n 0 > tstctl
+ */
+DEFINE_SIMPLE_ATTRIBUTE(tc_tstctl_fops, NULL, tc_tstctl_set, "%llu\n");
+
static const struct drm_connector_funcs tc_connector_funcs = {
.detect = tc_connector_detect,
.fill_modes = drm_helper_probe_single_connector_modes,
@@ -1530,9 +1614,15 @@ static irqreturn_t tc_irq_handler(int irq, void *arg)
return IRQ_HANDLED;
}

+static void tc_remove_debugfs(void *data)
+{
+ debugfs_remove_recursive(data);
+}
+
static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
+ struct dentry *debugfs;
struct tc_data *tc;
int ret;

@@ -1541,6 +1631,7 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
return -ENOMEM;

tc->dev = dev;
+ mutex_init(&tc->tstctl_lock);

/* port@2 is the output port */
ret = drm_of_find_panel_or_bridge(dev->of_node, 2, 0, &tc->panel, NULL);
@@ -1671,6 +1762,13 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)

i2c_set_clientdata(client, tc);

+ debugfs = debugfs_create_dir(dev_name(dev), NULL);
+ if (!IS_ERR(debugfs)) {
+ debugfs_create_file_unsafe("tstctl", 0200, debugfs, tc,
+ &tc_tstctl_fops);
+ devm_add_action_or_reset(dev, tc_remove_debugfs, debugfs);
+ }
+
return 0;
}

--
2.21.0
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