On 2018-05-16 12:56, Andrzej Hajda wrote:
I suppose you wanted to respond on the list, so I have added back all
recipients.

On 16.05.2018 06:39, spa...@codeaurora.org wrote:
On 2018-05-15 19:23, Andrzej Hajda wrote:
On 15.05.2018 07:52, Sandeep Panda wrote:
Add support for TI's sn65dsi86 dsi2edp bridge chip.
The chip converts DSI transmitted signal to eDP signal,
which is fed to the connected eDP panel.

This chip can be controlled via either i2c interface or
dsi interface. Currently in driver all the control registers
are being accessed through i2c interface only.
Also as of now HPD support has not been added to bridge
chip driver.

Changes in v1:
- Split the dt-bindings and the driver support into separate patches
   (Andrzej Hajda).
- Use of gpiod APIs to parse and configure gpios instead of obsolete
ones
   (Andrzej Hajda).
 - Use macros to define the register offsets (Andrzej Hajda).

Changes in v2:
 - Separate out edp panel specific HW resource handling from bridge
   driver and create a separate edp panel drivers to handle panel
   specific mode information and HW resources (Sean Paul).
 - Replace pr_* APIs to DRM_* APIs to log error or debug information
   (Sean Paul).
- Remove some of the unnecessary structure/variable from driver (Sean
   Paul).
 - Rename the function and structure prefix "sn65dsi86" to
"ti_sn_bridge"
   (Sean Paul / Rob Herring).
 - Remove most of the hard-coding and modified the bridge init
sequence
   based on current mode (Sean Paul).
 - Remove the existing function to retrieve the EDID data and
   implemented this as an i2c_adapter and use drm_get_edid() (Sean
Paul).
 - Remove the dummy irq handler implementation, will add back the
   proper irq handling later (Sean Paul).
 - Capture the required enable gpios in a single array based on dt
entry
instead of having individual descriptor for each gpio (Sean Paul).

Changes in v3:
 - Remove usage of irq_gpio and replace it as "interrupts" property
(Rob
   Herring).
 - Remove the unnecessary header file inclusions (Sean Paul).
 - Rearrange the header files in alphabetical order (Sean Paul).
 - Use regmap interface to perform i2c transactions.
 - Update Copyright/License field and address other review comments
   (Jordan Crouse).

Changes in v4:
 - Update License/Copyright (Sean Paul).
 - Add Kconfig and Makefile changes (Sean Paul).
 - Drop i2c gpio handling from this bridge driver, since i2c sda/scl
gpios
   will be handled by i2c master.
 - Update required supplies names.
 - Remove unnecessary goto statements (Sean Paul).
 - Add mutex lock to power_ctrl API to avoid race conditions (Sean
   Paul).
 - Add support to parse reference clk frequency from dt(optional).
 - Update the bridge chip enable/disable sequence.

Changes in v5:
 - Fixed Kbuild test service reported warnings.

Changes in v6:
 - Use PM runtime based ref-counting instead of local ref_count
mechanism
   (Stephen Boyd).
 - Clean up some debug logs and indentations (Sean Paul).
 - Simplify dp rate calculation (Sean Paul).
- Add support to configure refclk based on input REFCLK pin or DACP/N
   pin (Stephen Boyd).

Signed-off-by: Sandeep Panda <spa...@codeaurora.org>
---
 drivers/gpu/drm/bridge/Kconfig        |   9 +
 drivers/gpu/drm/bridge/Makefile       |   1 +
 drivers/gpu/drm/bridge/ti-sn65dsi86.c | 766
++++++++++++++++++++++++++++++++++
 3 files changed, 776 insertions(+)
 create mode 100644 drivers/gpu/drm/bridge/ti-sn65dsi86.c

diff --git a/drivers/gpu/drm/bridge/Kconfig
b/drivers/gpu/drm/bridge/Kconfig
index 3b99d5a..8153150 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -108,6 +108,15 @@ config DRM_TI_TFP410
        ---help---
          Texas Instruments TFP410 DVI/HDMI Transmitter driver

+config DRM_TI_SN65DSI86
+       tristate "TI SN65DSI86 DSI to eDP bridge"
+       depends on OF
+       select DRM_KMS_HELPER
+       select REGMAP_I2C
+       select DRM_PANEL
+       ---help---
+         Texas Instruments SN65DSI86 DSI to eDP Bridge driver
+
 source "drivers/gpu/drm/bridge/analogix/Kconfig"

 source "drivers/gpu/drm/bridge/adv7511/Kconfig"
diff --git a/drivers/gpu/drm/bridge/Makefile
b/drivers/gpu/drm/bridge/Makefile
index 373eb28..3711be8 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -12,4 +12,5 @@ obj-$(CONFIG_DRM_TOSHIBA_TC358767) += tc358767.o
 obj-$(CONFIG_DRM_ANALOGIX_DP) += analogix/
 obj-$(CONFIG_DRM_I2C_ADV7511) += adv7511/
 obj-$(CONFIG_DRM_TI_TFP410) += ti-tfp410.o
+obj-$(CONFIG_DRM_TI_SN65DSI86) += ti-sn65dsi86.o
 obj-y += synopsys/
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
new file mode 100644
index 0000000..1d3e549
--- /dev/null
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -0,0 +1,766 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018, The Linux Foundation. All rights reserved.
+ */
+
+#include <drm/drmP.h>
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_panel.h>
+#include <linux/clk.h>
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/of_gpio.h>
+#include <linux/of_graph.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+#define SN_BRIDGE_REVISION_ID 0x2
+
+/* Link Training specific registers */
+#define SN_DEVICE_REV_REG                      0x08
+#define SN_HPD_DISABLE_REG                     0x5C
+#define SN_REFCLK_FREQ_REG                     0x0A
+#define SN_DSI_LANES_REG                       0x10
+#define SN_DSIA_CLK_FREQ_REG                   0x12
+#define SN_ENH_FRAME_REG                       0x5A
+#define SN_SSC_CONFIG_REG                      0x93
+#define SN_DATARATE_CONFIG_REG                 0x94
+#define SN_PLL_ENABLE_REG                      0x0D
+#define SN_SCRAMBLE_CONFIG_REG                 0x95
+#define SN_AUX_WDATA0_REG                      0x64
+#define SN_AUX_ADDR_19_16_REG                  0x74
+#define SN_AUX_ADDR_15_8_REG                   0x75
+#define SN_AUX_ADDR_7_0_REG                    0x76
+#define SN_AUX_LENGTH_REG                      0x77
+#define SN_AUX_CMD_REG                         0x78
+#define SN_ML_TX_MODE_REG                      0x96
+/* video config specific registers */
+#define SN_CHA_ACTIVE_LINE_LENGTH_LOW_REG      0x20
+#define SN_CHA_ACTIVE_LINE_LENGTH_HIGH_REG     0x21
+#define SN_CHA_VERTICAL_DISPLAY_SIZE_LOW_REG   0x24
+#define SN_CHA_VERTICAL_DISPLAY_SIZE_HIGH_REG  0x25
+#define SN_CHA_HSYNC_PULSE_WIDTH_LOW_REG       0x2C
+#define SN_CHA_HSYNC_PULSE_WIDTH_HIGH_REG      0x2D
+#define SN_CHA_VSYNC_PULSE_WIDTH_LOW_REG       0x30
+#define SN_CHA_VSYNC_PULSE_WIDTH_HIGH_REG      0x31
+#define SN_CHA_HORIZONTAL_BACK_PORCH_REG       0x34
+#define SN_CHA_VERTICAL_BACK_PORCH_REG         0x36
+#define SN_CHA_HORIZONTAL_FRONT_PORCH_REG      0x38
+#define SN_CHA_VERTICAL_FRONT_PORCH_REG                0x3A
+#define SN_DATA_FORMAT_REG                     0x5B
+
+#define MIN_DSI_CLK_FREQ_MHZ   40
+
+/* fudge factor required to account for 8b/10b encoding */
+#define DP_CLK_FUDGE_NUM       10
+#define DP_CLK_FUDGE_DEN       8
+
+#define DPPLL_CLK_SRC_REFCLK   0
+#define DPPLL_CLK_SRC_DSICLK   1
+
+#define SN_DSIA_REFCLK_OFFSET  1
+#define SN_DSIA_LANE_OFFSET    3
+#define SN_DP_LANE_OFFSET      4
+#define SN_DP_DATA_RATE_OFFSET 5
+#define SN_TIMING_HIGH_OFFSET  8
+
+#define SN_ENABLE_VID_STREAM_BIT       BIT(3)
+#define SN_DSIA_NUM_LANES_BITS         (BIT(4) | BIT(3))
+#define SN_DP_NUM_LANES_BITS           (BIT(5) | BIT(4))
+#define SN_DP_DATA_RATE_BITS           (BIT(7) | BIT(6) | BIT(5))
+#define SN_HPD_DISABLE_BIT             BIT(0)
+
+struct ti_sn_bridge {
+       struct device                   *dev;
+       struct regmap                   *regmap;
I have not spotted who advised you to use regmap, I think unless you
share hardware between multiple drivers it is an overkill.
Are there any features of this interface to use it over i2c?

Since we are using the i2c mechanism to update the control registers
of the bridge, thought that regmap gives a proper interface for handling all the register control operations like read/write/update_bit/mask etc. Also most of the bridge driver present in drm are using this mechanism.

Yes, I know many ppl advertises it but also many are against using it in
such simple cases. Anyway I do not want to force you to remove it, do
what you prefer.


+       struct drm_bridge               bridge;
+       struct drm_connector            connector;
+       struct device_node              *host_node;
+       struct mipi_dsi_device          *dsi;
+       struct clk                      *refclk;
+       struct drm_panel                *panel;
+       struct gpio_desc                *enable_gpio;
+       unsigned int                    num_supplies;
+       struct regulator_bulk_data      *supplies;
+       struct i2c_adapter              *ddc;
+       struct drm_display_mode         curr_mode;
I think you can drop this field, current mode is always available via:

pdata->bridge.encoder.crtc->state->adjusted_mode;


Ok. i will remove this curr_mode.

+};
+
+static const struct regmap_range ti_sn_bridge_volatile_ranges[] = {
+       { .range_min = 0, .range_max = 0xff },
+};
+
+static const struct regmap_access_table ti_sn_bridge_volatile_table =
{
+       .yes_ranges = ti_sn_bridge_volatile_ranges,
+       .n_yes_ranges = ARRAY_SIZE(ti_sn_bridge_volatile_ranges),
+};
+
+static const struct regmap_config ti_sn_bridge_regmap_config = {
+       .reg_bits = 8,
+       .val_bits = 8,
+       .volatile_table = &ti_sn_bridge_volatile_table,
+       .cache_type = REGCACHE_NONE,
+};
+
+#ifdef CONFIG_PM
Please mark PM callbacks with __maybe_unused instead if conditional
macros.

Ok.

+static int ti_sn_bridge_resume(struct device *dev)
+{
+       struct ti_sn_bridge *pdata = dev_get_drvdata(dev);
+       int ret = 0;
+
+       ret = regulator_bulk_enable(pdata->num_supplies, pdata->supplies);
+       if (ret) {
+               DRM_ERROR("failed to enable supplies %d\n", ret);
+               return ret;
+       }
+
+       gpiod_set_value(pdata->enable_gpio, 1);
+
+       return ret;
+}
+
+static int ti_sn_bridge_suspend(struct device *dev)
+{
+       struct ti_sn_bridge *pdata = dev_get_drvdata(dev);
+       int ret = 0;
+
+       gpiod_set_value(pdata->enable_gpio, 0);
+
+ ret = regulator_bulk_disable(pdata->num_supplies, pdata->supplies);
+       if (ret)
+               DRM_ERROR("failed to disable supplies %d\n", ret);
+
+       return ret;
+}
+#endif
+
+static const struct dev_pm_ops ti_sn_bridge_pm_ops = {
+ SET_RUNTIME_PM_OPS(ti_sn_bridge_suspend, ti_sn_bridge_resume, NULL)
+};
+
+/* Connector funcs */
+static struct ti_sn_bridge *
+connector_to_ti_sn_bridge(struct drm_connector *connector)
+{
+       return container_of(connector, struct ti_sn_bridge, connector);
+}
+
+static int ti_sn_bridge_connector_get_modes(struct drm_connector
*connector)
+{
+       struct ti_sn_bridge *pdata = connector_to_ti_sn_bridge(connector);
+       struct drm_panel *panel = pdata->panel;
+       struct edid *edid;
+       u32 num_modes;
+
+       if (panel) {
+               DRM_DEBUG_KMS("get mode from connected drm_panel\n");
+               return drm_panel_get_modes(panel);
+       }
+
+       if (!pdata->ddc)
+               return 0;
+
+       pm_runtime_get_sync(pdata->dev);
+       edid = drm_get_edid(connector, pdata->ddc);
+       pm_runtime_put_sync(pdata->dev);
+       if (!edid)
+               return 0;
+
+       drm_mode_connector_update_edid_property(connector, edid);
+       num_modes = drm_add_edid_modes(connector, edid);
+       kfree(edid);
+
+       return num_modes;
+}
+
+static enum drm_mode_status
+ti_sn_bridge_connector_mode_valid(struct drm_connector *connector,
+                            struct drm_display_mode *mode)
+{
+       /* maximum supported resolution is 4K at 60 fps */
+       if (mode->clock > 594000)
+               return MODE_CLOCK_HIGH;
+
+       return MODE_OK;
+}
+
+static struct drm_connector_helper_funcs
ti_sn_bridge_connector_helper_funcs = {
+       .get_modes = ti_sn_bridge_connector_get_modes,
+       .mode_valid = ti_sn_bridge_connector_mode_valid,
+};
+
+static enum drm_connector_status
+ti_sn_bridge_connector_detect(struct drm_connector *connector, bool
force)
+{
+       struct ti_sn_bridge *pdata = connector_to_ti_sn_bridge(connector);
+
+       /**
+        * TODO: Currently if drm_panel is present, then always
+        * return the status as connected. Need to add support to detect
+        * device state for no panel(hot pluggable) scenarios.
+        */
+       if (pdata->panel)
+               return connector_status_connected;
+       else
+               return connector_status_unknown;
+}
+
+static const struct drm_connector_funcs ti_sn_bridge_connector_funcs
= {
+       .fill_modes = drm_helper_probe_single_connector_modes,
+       .detect = ti_sn_bridge_connector_detect,
+       .destroy = drm_connector_cleanup,
+       .reset = drm_atomic_helper_connector_reset,
+       .atomic_duplicate_state =
drm_atomic_helper_connector_duplicate_state,
+       .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static struct ti_sn_bridge *bridge_to_ti_sn_bridge(struct drm_bridge
*bridge)
+{
+       return container_of(bridge, struct ti_sn_bridge, bridge);
+}
+
+static int ti_sn_bridge_read_device_rev(struct ti_sn_bridge *pdata)
+{
+       unsigned int rev = 0;
+       int ret = 0;
+
+       ret = regmap_read(pdata->regmap, SN_DEVICE_REV_REG, &rev);
+       if (ret) {
+               DRM_ERROR("Revision read failed %d\n", ret);
+               return ret;
+       }
+
+       if (rev != SN_BRIDGE_REVISION_ID) {
+               DRM_ERROR("ti_sn_bridge revision id: 0x%x mismatch\n", rev);
+               ret = -EINVAL;
+       }
Are you sure it won't work with other revisions?

The datasheet which i have, mentions the revision to be 0x2. I am not
sure whether this driver works with other revisions, that's why i have
put this check.
Also this check helps to confirm if the gpio and supplies of the bridge
chip has been successfully enabled not depending on the value read.

So maybe better convert DRM_ERROR to warning and continue.

Ok. I will remove the failure return in case of id mismatch and just print a warning.

+
+       return ret;
+}
+
+static const char * const ti_sn_bridge_supply_names[] = {
+       "vcca",
+       "vcc",
+       "vccio",
+       "vpll",
+};
+
+static int ti_sn_bridge_parse_regulators(struct ti_sn_bridge *pdata)
+{
+       unsigned int i;
+
+       pdata->num_supplies = ARRAY_SIZE(ti_sn_bridge_supply_names);
+
+       pdata->supplies = devm_kcalloc(pdata->dev, pdata->num_supplies,
+                                      sizeof(*pdata->supplies), GFP_KERNEL);
It seems there is constant number of supplies. You can convert supplies
to array and avoid dynamic allocation.

Just want to understand here what is the issue with dynamic allocation
here?
We are using device managed allocation, so the resource management will
be properly
done by kernel.

Just less code, no extra allocations, no extra resource management.
Dynamic allocations in such case makes sense only if array size is
computed in runtime.

Ok.

+       if (!pdata->supplies)
+               return -ENOMEM;
+
+       for (i = 0; i < pdata->num_supplies; i++)
+               pdata->supplies[i].supply = ti_sn_bridge_supply_names[i];
+
+       return devm_regulator_bulk_get(pdata->dev,
+                                      pdata->num_supplies, pdata->supplies);
+}
+
+static int ti_sn_bridge_attach_panel(struct ti_sn_bridge *pdata)
+{
+       struct device_node *panel_node, *port, *endpoint;
+
+       pdata->panel = NULL;
+       port = of_graph_get_port_by_id(pdata->dev->of_node, 1);
+       if (!port)
+               return 0;
+
+       endpoint = of_get_child_by_name(port, "endpoint");
+       of_node_put(port);
+       if (!endpoint) {
+               DRM_ERROR("no output endpoint found\n");
+               return -EINVAL;
+       }
Why not of_graph_get_endpoint_by_regs ?

+
+       panel_node = of_graph_get_remote_port_parent(endpoint);
+       of_node_put(endpoint);
+       if (!panel_node) {
+               DRM_ERROR("no output node found\n");
+               return -EINVAL;
+       }
Or even of_graph_get_remote_node?

+
+       pdata->panel = of_drm_find_panel(panel_node);
+       of_node_put(panel_node);
Or even, even drm_of_find_panel_or_bridge ? :)
Ok. i will use drm_of_find_panel_or_bridge() here.

+       if (!pdata->panel) {
+               DRM_ERROR("no panel node found\n");
+               return -EINVAL;
You should probably return -EPROBE_DEFER here.

This API may not be called from probe(), is it ok if we return
-EPROBE_DEFER here?

Ahh, OK, but in such case this is incorrect, see below.


+       }
+       drm_panel_attach(pdata->panel, &pdata->connector);
+       DRM_DEBUG_KMS("drm panel attached to ti_sn_bridge\n");
+
+       return 0;
+}
+
+static int ti_sn_bridge_attach(struct drm_bridge *bridge)
+{
+       struct mipi_dsi_host *host;
+       struct mipi_dsi_device *dsi;
+       struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
+       int ret;
+       const struct mipi_dsi_device_info info = { .type = "ti_sn_bridge",
+                                                  .channel = 0,
+                                                  .node = NULL,
+                                                };
+
+       if (!bridge->encoder) {
+               DRM_ERROR("Parent encoder object not found\n");
+               return -ENODEV;
+       }
+
+       /* HPD not supported */
+       pdata->connector.polled = 0;
You can skip this line.

OK.

+
+       ret = drm_connector_init(bridge->dev, &pdata->connector,
+                                &ti_sn_bridge_connector_funcs,
+                                DRM_MODE_CONNECTOR_eDP);
+       if (ret) {
+               DRM_ERROR("Failed to initialize connector with drm\n");
+               return ret;
+       }
+
+       drm_connector_helper_add(&pdata->connector,
+                                &ti_sn_bridge_connector_helper_funcs);
+       drm_mode_connector_attach_encoder(&pdata->connector,
bridge->encoder);
+
+       host = of_find_mipi_dsi_host_by_node(pdata->host_node);
+       if (!host) {
+               DRM_ERROR("failed to find dsi host\n");
+               return -ENODEV;
Again -EPROBE_DEFER.

This API may not be called from probe(), is it ok if we return
-EPROBE_DEFER here?

ditto


+       }
+
+       dsi = mipi_dsi_device_register_full(host, &info);
+       if (IS_ERR(dsi)) {
+               DRM_ERROR("failed to create dsi device\n");
+               ret = PTR_ERR(dsi);
+               return ret;
+       }
+
+       /* TODO: setting to 4 lanes always for now */
+       dsi->lanes = 4;
+       dsi->format = MIPI_DSI_FMT_RGB888;
+       dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
+                         MIPI_DSI_MODE_EOT_PACKET | MIPI_DSI_MODE_VIDEO_HSE;
+
+       ret = mipi_dsi_attach(dsi);
+       if (ret < 0) {
+               DRM_ERROR("failed to attach dsi to host\n");
+               mipi_dsi_device_unregister(dsi);
+               return ret;
+       }
+
+       pdata->dsi = dsi;
+
+       DRM_DEBUG_KMS("ti_sn_bridge attached to dsi\n");
+       /* attach panel to bridge */
+       ti_sn_bridge_attach_panel(pdata);
 
Function can fail, you should handle it.

This is not fatal, if this function fails then we assume there is no edp
panel attached to this bridge.

So it seems wrong to me. You do not have guarantee that panel driver is
bound at this moment. So in case of different driver binding order you
will end up with incorrect setup: bridge will work with assumption there is no panel behind it, but the panel is there, it will be just probed later.

I think the proper solution here is to do not advertise bridge (ie call
drm_bridge_add), until all required resources are present, including DSI
host and panel. And to make it clear, if the panel is defined in
bindings it means it is required.


Ok. So i will move this attach code to ti_sn_bridge_probe() and if i dont get the panel there i will return -EPROBE_DEFER. Currently HPD is not supported in the driver, so we will rely on the panel to successfully finish bridge driver's probe.

+
+       return 0;
+}
+
+static void ti_sn_bridge_mode_set(struct drm_bridge *bridge,
+                                   struct drm_display_mode *mode,
+                                   struct drm_display_mode *adj_mode)
+{
+       struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
+
+       DRM_DEBUG("mode_set: hdisplay=%d, vdisplay=%d, vrefresh=%d,
clock=%d\n",
+               adj_mode->hdisplay, adj_mode->vdisplay,
+               adj_mode->vrefresh, adj_mode->clock);
+
+       drm_mode_copy(&pdata->curr_mode, adj_mode);
+}
This callback can be dropped, see comment for curr_mode.

+
+static void ti_sn_bridge_disable(struct drm_bridge *bridge)
+{
+       struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
+       struct drm_panel *panel = pdata->panel;
+
+       if (panel) {
+               drm_panel_disable(panel);
+               drm_panel_unprepare(panel);
+       }
+
+       /* disable video stream */
+       regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG,
+                          SN_ENABLE_VID_STREAM_BIT, 0);
+       /* semi auto link training mode OFF */
+       regmap_write(pdata->regmap, SN_ML_TX_MODE_REG, 0);
+       /* disable DP PLL */
+       regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 0);
+}
+
+static u32 ti_sn_bridge_get_dsi_freq(struct ti_sn_bridge *pdata)
+{
+       u32 bit_rate_khz, clk_freq_khz;
+       struct drm_display_mode *mode = &pdata->curr_mode;
+
+       bit_rate_khz = mode->clock *
+                       mipi_dsi_pixel_format_to_bpp(pdata->dsi->format);
+       clk_freq_khz = bit_rate_khz / (pdata->dsi->lanes * 2);
+
+       return clk_freq_khz;
+}
+
+#define REFCLK_LUT_SIZE        5
+
+/* clk frequencies supported by bridge in Hz in case derived from
REFCLK pin */
+static const u32 ti_sn_bridge_refclk_lut[] = {
+       12000000,
+       19200000,
+       26000000,
+       27000000,
+       38400000,
+};
+
+/* clk frequencies supported by bridge in Hz in case derived from
DACP/N pin */
+static const u32 ti_sn_bridge_dsiclk_lut[] = {
+       468000000,
+       384000000,
+       416000000,
+       486000000,
+       460800000,
+};
+
+static void ti_sn_bridge_set_refclk(struct ti_sn_bridge *pdata)
+{
+       int i = 0;
+       u8 refclk_src;
+       u32 refclk_rate;
+       const u32 *refclk_lut;
+
+       if (pdata->refclk) {
+               refclk_src = DPPLL_CLK_SRC_REFCLK;
+               refclk_rate = clk_get_rate(pdata->refclk);
+               refclk_lut = ti_sn_bridge_refclk_lut;
+               clk_prepare_enable(pdata->refclk);
+       } else {
+               refclk_src = DPPLL_CLK_SRC_DSICLK;
+               refclk_rate = ti_sn_bridge_get_dsi_freq(pdata) * 1000;
+               refclk_lut = ti_sn_bridge_dsiclk_lut;
+       }
+
+       /* for i equals to REFCLK_LUT_SIZE means default frequency */
+       for (i = 0; i < REFCLK_LUT_SIZE; i++)
+               if (refclk_lut[i] == refclk_rate)
+                       break;
+
+       regmap_write(pdata->regmap, SN_REFCLK_FREQ_REG,
+                    (refclk_src | (i << SN_DSIA_REFCLK_OFFSET)));
+}
+
+/**
+ * LUT index corresponds to register value and
+ * LUT values corresponds to dp data rate supported
+ * by the bridge in Mbps unit.
+ */
+static const unsigned int ti_sn_bridge_dp_rate_lut[] = {
+       0, 1620, 2160, 2430, 2700, 3240, 4320, 5400
+};
+
+static void ti_sn_bridge_set_dsi_dp_rate(struct ti_sn_bridge *pdata)
+{
+       unsigned int bit_rate_mhz, clk_freq_mhz, dp_rate_mhz;
+       unsigned int val = 0, i = 0;
+       struct drm_display_mode *mode = &pdata->curr_mode;
+
+       /* set DSIA clk frequency */
+       bit_rate_mhz = (mode->clock / 1000) *
+                       mipi_dsi_pixel_format_to_bpp(pdata->dsi->format);
+       clk_freq_mhz = bit_rate_mhz / (pdata->dsi->lanes * 2);
+
+       /* for each increment in val, frequency increases by 5MHz */
+       val = (MIN_DSI_CLK_FREQ_MHZ / 5) +
+               (((clk_freq_mhz - MIN_DSI_CLK_FREQ_MHZ) / 5) & 0xFF);
+       regmap_write(pdata->regmap, SN_DSIA_CLK_FREQ_REG, val);
+
+       /* set DP data rate */
+       dp_rate_mhz = ((bit_rate_mhz / pdata->dsi->lanes) *
DP_CLK_FUDGE_NUM) /
+                                                       DP_CLK_FUDGE_DEN;
+       for (i = 0; i < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut); i++)
+               if (ti_sn_bridge_dp_rate_lut[i] > dp_rate_mhz)
+                       break;
+       if (i == ARRAY_SIZE(ti_sn_bridge_dp_rate_lut))
+               i--; /* set to maximum possible */
Just use: for (i = 0; i < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1;
i++)

Ok.

+
+       regmap_update_bits(pdata->regmap, SN_DATARATE_CONFIG_REG,
+                          SN_DP_DATA_RATE_BITS, i << SN_DP_DATA_RATE_OFFSET);
+}
+
+static void ti_sn_bridge_set_video_timings(struct ti_sn_bridge
*pdata)
+{
+       struct drm_display_mode *mode = &pdata->curr_mode;
+
+       regmap_write(pdata->regmap, SN_CHA_ACTIVE_LINE_LENGTH_LOW_REG,
+                    mode->hdisplay & 0xFF);
+       regmap_write(pdata->regmap, SN_CHA_ACTIVE_LINE_LENGTH_HIGH_REG,
+                    (mode->hdisplay >> SN_TIMING_HIGH_OFFSET) & 0xFF);
+       regmap_write(pdata->regmap, SN_CHA_VERTICAL_DISPLAY_SIZE_LOW_REG,
+                    mode->vdisplay & 0xFF);
+       regmap_write(pdata->regmap, SN_CHA_VERTICAL_DISPLAY_SIZE_HIGH_REG,
+                    (mode->vdisplay >> SN_TIMING_HIGH_OFFSET) & 0xFF);
+       regmap_write(pdata->regmap, SN_CHA_HSYNC_PULSE_WIDTH_LOW_REG,
+                    (mode->hsync_end - mode->hsync_start) & 0xFF);
+       regmap_write(pdata->regmap, SN_CHA_HSYNC_PULSE_WIDTH_HIGH_REG,
+                    ((mode->hsync_end - mode->hsync_start) >>
+                     SN_TIMING_HIGH_OFFSET) & 0xFF);
+       regmap_write(pdata->regmap, SN_CHA_VSYNC_PULSE_WIDTH_LOW_REG,
+                    (mode->vsync_end - mode->vsync_start) & 0xFF);
+       regmap_write(pdata->regmap, SN_CHA_VSYNC_PULSE_WIDTH_HIGH_REG,
+                    ((mode->vsync_end - mode->vsync_start) >>
+                     SN_TIMING_HIGH_OFFSET) & 0xFF);
+       regmap_write(pdata->regmap, SN_CHA_HORIZONTAL_BACK_PORCH_REG,
+                    (mode->htotal - mode->hsync_end) & 0xFF);
+       regmap_write(pdata->regmap, SN_CHA_VERTICAL_BACK_PORCH_REG,
+                    (mode->vtotal - mode->vsync_end) & 0xFF);
+       regmap_write(pdata->regmap, SN_CHA_HORIZONTAL_FRONT_PORCH_REG,
+                    (mode->hsync_start - mode->hdisplay) & 0xFF);
+       regmap_write(pdata->regmap, SN_CHA_VERTICAL_FRONT_PORCH_REG,
+                    (mode->vsync_start - mode->vdisplay) & 0xFF);
+       usleep_range(10000, 10500); /* 10ms delay recommended by spec */
+}
+
+static void ti_sn_bridge_enable(struct drm_bridge *bridge)
+{
+       struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
+       struct drm_panel *panel = pdata->panel;
+       unsigned int val = 0;
+
+       if (panel) {
+               drm_panel_prepare(panel);
+               /* in case drm_panel is connected then HPD is not supported */
+               regmap_update_bits(pdata->regmap, SN_HPD_DISABLE_REG,
+                                  SN_HPD_DISABLE_BIT, SN_HPD_DISABLE_BIT);
+       }
+
+       /* DSI_A lane config */
+       val = (4 - pdata->dsi->lanes) << SN_DSIA_LANE_OFFSET;
+       regmap_update_bits(pdata->regmap, SN_DSI_LANES_REG,
+                          SN_DSIA_NUM_LANES_BITS, val);
+
+       /* DP lane config */
+       val = (pdata->dsi->lanes - 1) << SN_DP_LANE_OFFSET;
+       regmap_update_bits(pdata->regmap, SN_SSC_CONFIG_REG,
+                          SN_DP_NUM_LANES_BITS, val);
+
+       /* set dsi/dp clk frequency value */
+       ti_sn_bridge_set_dsi_dp_rate(pdata);
+
+       /* enable DP PLL */
+       regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 1);
+       usleep_range(10000, 10500); /* 10ms delay recommended by spec */
+
+       /**
+        * The SN65DSI86 only supports ASSR Display Authentication method
and
+ * this method is enabled by default. An eDP panel must support this
+        * authentication method. We need to enable this method in the eDP
panel
+        * at DisplayPort address 0x0010A prior to link training.
+        */
+       regmap_write(pdata->regmap, SN_AUX_WDATA0_REG, 0x01);
+       regmap_write(pdata->regmap, SN_AUX_ADDR_19_16_REG, 0x00);
+       regmap_write(pdata->regmap, SN_AUX_ADDR_15_8_REG, 0x01);
+       regmap_write(pdata->regmap, SN_AUX_ADDR_7_0_REG, 0x0A);
+       regmap_write(pdata->regmap, SN_AUX_LENGTH_REG, 0x01);
+       regmap_write(pdata->regmap, SN_AUX_CMD_REG, 0x81);
+       usleep_range(10000, 10500); /* 10ms delay recommended by spec */
+
+       /* Semi auto link training mode */
+       regmap_write(pdata->regmap, SN_ML_TX_MODE_REG, 0x0A);
+       msleep(20); /* 20ms delay recommended by spec */
+
+       /* config video parameters */
+       ti_sn_bridge_set_video_timings(pdata);
+
+       /* enable video stream */
+       regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG,
+                          SN_ENABLE_VID_STREAM_BIT, SN_ENABLE_VID_STREAM_BIT);
+
+       if (panel)
+               drm_panel_enable(panel);
+}
+
+static void ti_sn_bridge_pre_enable(struct drm_bridge *bridge)
+{
+       struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
+
+       pm_runtime_get_sync(pdata->dev);
+
+       /* configure bridge CLK_SRC and ref_clk */
+       ti_sn_bridge_set_refclk(pdata);
+}
+
+static void ti_sn_bridge_post_disable(struct drm_bridge *bridge)
+{
+       struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
+
+       if (pdata->refclk)
+               clk_disable_unprepare(pdata->refclk);
+
+       pm_runtime_put_sync(pdata->dev);
+}
+
+static const struct drm_bridge_funcs ti_sn_bridge_funcs = {
+       .attach = ti_sn_bridge_attach,
+       .pre_enable = ti_sn_bridge_pre_enable,
+       .enable = ti_sn_bridge_enable,
+       .disable = ti_sn_bridge_disable,
+       .post_disable = ti_sn_bridge_post_disable,
+       .mode_set = ti_sn_bridge_mode_set,
+};
+
+static int ti_sn_bridge_parse_dsi_host(struct ti_sn_bridge *pdata)
+{
+       struct device_node *np = pdata->dev->of_node;
+       struct device_node *end_node;
+
+       end_node = of_graph_get_endpoint_by_regs(np, 0, 0);
+       if (!end_node) {
+               DRM_ERROR("remote endpoint not found\n");
+               return -ENODEV;
+       }
+
+       pdata->host_node = of_graph_get_remote_port_parent(end_node);
+       of_node_put(end_node);
+       if (!pdata->host_node) {
+               DRM_ERROR("remote node not found\n");
+               return -ENODEV;
+       }
+       of_node_put(pdata->host_node);
Why not of_graph_get_remote_node ?

Just for my understanding, is of_graph_get_remote_port_parent not
recommended? what is the benefit of using of_graph_get_remote_node()?


Because it encapsulates both of_graph_get_endpoint_by_regs and
of_graph_get_remote_port_parent with correct node reference management.

Ok.

+
+       return 0;
+}
+
+static int ti_sn_bridge_probe(struct i2c_client *client,
+        const struct i2c_device_id *id)
+{
+       struct ti_sn_bridge *pdata;
+       struct device_node *ddc_node;
+       int ret = 0;
+
+       if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+               DRM_ERROR("device doesn't support I2C\n");
+               return -ENODEV;
+       }
+
+       pdata = devm_kzalloc(&client->dev, sizeof(struct ti_sn_bridge),
+                            GFP_KERNEL);
+       if (!pdata)
+               return -ENOMEM;
+
+       pdata->dev = &client->dev;
+       dev_set_drvdata(&client->dev, pdata);
+
+       pdata->regmap = devm_regmap_init_i2c(client,
+                                            &ti_sn_bridge_regmap_config);
+       if (IS_ERR(pdata->regmap)) {
+               DRM_ERROR("regmap i2c init failed\n");
+               return PTR_ERR(pdata->regmap);
+       }
+
+       pdata->enable_gpio = devm_gpiod_get(pdata->dev,
+                                           "enable", GPIOD_OUT_LOW);
+       if (IS_ERR(pdata->enable_gpio)) {
+               DRM_ERROR("failed to get enable gpio from DT\n");
+               ret = PTR_ERR(pdata->enable_gpio);
+               return ret;
+       }
+
+       ret = ti_sn_bridge_parse_regulators(pdata);
+       if (ret) {
+               DRM_ERROR("failed to parse regulators\n");
+               return ret;
+       }
+
+       ret = ti_sn_bridge_parse_dsi_host(pdata);
+       if (ret)
+               return ret;
+
+       pm_runtime_enable(pdata->dev);
+       pm_runtime_get_sync(pdata->dev);
+       ret = ti_sn_bridge_read_device_rev(pdata);
+       pm_runtime_put_sync(pdata->dev);
I would put it into (pre) enable callbacks, maybe with marking it to
run
only once.

do you mean we should put the ti_sn_bridge_read_device_rev() in pre
enable callback?

Yes, to avoid unnecessary switching on/off device.

Ok. in that case i have add a rev field in the private data and check for this be non-zero every time pre_enable is called else read the rev.
Regards
Andrzej


Regards
Andrzej

+       if (ret)
+               goto err_rev_read;
+
+       pdata->refclk = devm_clk_get(pdata->dev, "refclk");
+
+ ddc_node = of_parse_phandle(pdata->dev->of_node, "ddc-i2c-bus", 0);
+       if (ddc_node) {
+               pdata->ddc = of_find_i2c_adapter_by_node(ddc_node);
+               of_node_put(ddc_node);
+               if (!pdata->ddc) {
+                       DRM_DEBUG_KMS("failed to read ddc node\n");
+                       ret = -EPROBE_DEFER;
+                       goto err_rev_read;
+               }
+       } else {
+               DRM_DEBUG_KMS("no ddc property found\n");
+       }
+
+       i2c_set_clientdata(client, pdata);
+
+       pdata->bridge.funcs = &ti_sn_bridge_funcs;
+       pdata->bridge.of_node = client->dev.of_node;
+
+       drm_bridge_add(&pdata->bridge);
+
+       return 0;
+
+err_rev_read:
+       pm_runtime_disable(pdata->dev);
+       return ret;
+}
+
+static int ti_sn_bridge_remove(struct i2c_client *client)
+{
+       struct ti_sn_bridge *pdata = i2c_get_clientdata(client);
+
+       if (!pdata)
+               return -EINVAL;
+
+       mipi_dsi_detach(pdata->dsi);
+       mipi_dsi_device_unregister(pdata->dsi);
+
+       drm_bridge_remove(&pdata->bridge);
+       pm_runtime_disable(pdata->dev);
+       i2c_put_adapter(pdata->ddc);
+
+       return 0;
+}
+
+static struct i2c_device_id ti_sn_bridge_id[] = {
+       { "ti,sn65dsi86", 0},
+       {},
+};
+MODULE_DEVICE_TABLE(i2c, ti_sn_bridge_id);
+
+static const struct of_device_id ti_sn_bridge_match_table[] = {
+       {.compatible = "ti,sn65dsi86"},
+       {},
+};
+MODULE_DEVICE_TABLE(of, ti_sn_bridge_match_table);
+
+static struct i2c_driver ti_sn_bridge_driver = {
+       .driver = {
+               .name = "ti_sn65dsi86",
+               .of_match_table = ti_sn_bridge_match_table,
+               .pm = &ti_sn_bridge_pm_ops,
+       },
+       .probe = ti_sn_bridge_probe,
+       .remove = ti_sn_bridge_remove,
+       .id_table = ti_sn_bridge_id,
+};
+
+module_i2c_driver(ti_sn_bridge_driver);
+MODULE_DESCRIPTION("sn65dsi86 DSI to eDP bridge driver");
+MODULE_LICENSE("GPL v2");


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