Re: [PATCH v8 1/4] drm/bridge: add support for sn65dsi86 bridge driver

spanda-sgV2jX0FEOL9JmXXK+q4OQ
2018-06-13T11:05:23Z

On 2018-06-06 04:29, Sean Paul wrote:
> On Tue, Jun 05, 2018 at 11:10:15AM +0530, 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).
>>
>> Changes in v7:
>> - Use static supply entries instead of dynamic allocation (Andrzej
>> Hajda).
>> - Defer bridge driver probe if panel is not probed (Andrzej Hajda).
>> - Update of_graph APIs for correct node reference management.
>> (Andrzej
>> Hajda).
>> - Remove local display_mode object (Andrzej Hajda).
>> - Remove version id check function from driver.
>>
>> Changes in v8:
>> - Move dsi register/attach function to bridge driver probe (Andrzej
>> Hajda).
>> - Introduce a new helper function to write 16bit words into
>> consecutive
>> registers (Andrzej Hajda).
>> - Remove unnecessary macros (Andrzej Hajda).
>>
>> Signed-off-by: Sandeep Panda <spanda@codeaurora.org>
>> ---
>> drivers/gpu/drm/bridge/Kconfig | 9 +
>> drivers/gpu/drm/bridge/Makefile | 1 +
>> drivers/gpu/drm/bridge/ti-sn65dsi86.c | 666
>> ++++++++++++++++++++++++++++++++++
>> 3 files changed, 676 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
>
> SN65DSI86 should be in front of TFP410 here and above.
>

Ok.

>> 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..add6e0f
>> --- /dev/null
>> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
>
> /snip
>
>> +
>> +#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++)
>
> Instead of REFCLK_LUT_SIZE, use a local variable, ie:
>
> size_t refclk_lut_size;
>
> ...
>
> if(pdata->refclk) {
> ...
> refclk_lut = ti_sn_bridge_refclk_lut;
> refclk_lut_size = ARRAY_SIZE(ti_sn_bridge_refclk_lut);
> ...
> } else {
> ...
> refclk_lut = ti_sn_bridge_dsiclk_lut;
> refclk_lut_size = ARRAY_SIZE(ti_sn_bridge_dsiclk_lut);
> }
>
> And remove REFCLK_LUT_SIZE.

Ok.

>
>> + 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->bridge.encoder->crtc->state->adjusted_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) - 1; i++)
>> + if (ti_sn_bridge_dp_rate_lut[i] > dp_rate_mhz)
>> + break;
>> +
>> + 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->bridge.encoder->crtc->state->adjusted_mode;
>> +
>> + ti_sn_bridge_write_u16(pdata, SN_CHA_ACTIVE_LINE_LENGTH_LOW_REG,
>> + mode->hdisplay);
>> + ti_sn_bridge_write_u16(pdata, SN_CHA_VERTICAL_DISPLAY_SIZE_LOW_REG,
>> + mode->vdisplay);
>> + ti_sn_bridge_write_u16(pdata, SN_CHA_HSYNC_PULSE_WIDTH_LOW_REG,
>> + mode->hsync_end - mode->hsync_start);
>> + ti_sn_bridge_write_u16(pdata, SN_CHA_VSYNC_PULSE_WIDTH_LOW_REG,
>> + mode->vsync_end - mode->vsync_start);
>> +
>> + 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);
>> + unsigned int val = 0;
>> +
>> + if (pdata->panel) {
>> + drm_panel_prepare(pdata->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, !0);
>
> What is !0?

There was a comment to make it like this, but i think SN_HPD_DISABLE_BIT
makes it more readable. I will change this as it was previously.
>
> Sean
>
> /snip