Re: [PATCH 2/2] drm: bridge: Add SN65DSI84 DSI to LVDS bridge

From: Michael Nazzareno Trimarchi
Date: Wed Jan 20 2021 - 07:21:08 EST

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In reply to: Jagan Teki: "Re: [PATCH 2/2] drm: bridge: Add SN65DSI84 DSI to LVDS bridge"
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On Wed, Jan 20, 2021 at 12:29 PM Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> On Wed, Jan 20, 2021 at 4:55 PM Michael Nazzareno Trimarchi
> <michael@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Hi Jagan
> >
> > On Wed, Jan 20, 2021 at 12:22 PM Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > SN65DSI84 is a Single Channel DSI to Dual-link LVDS bridge from
> > > Texas Instruments.
> > >
> > > SN65DSI83, SN65DSI85 are variants of the same family of bridge
> > > controllers.
> > >
> > > Right now the bridge driver is supporting a single link, dual-link
> > > support requires to initiate I2C Channel B registers.
> > >
> > > Tested with STM32MP1 MIPI DSI host design configuration.
> > >
> > > Signed-off-by: Matteo Lisi <matteo.lisi@xxxxxxxxxxx>
> > > Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
> > > ---
> > > MAINTAINERS | 6 +
> > > drivers/gpu/drm/bridge/Kconfig | 19 +
> > > drivers/gpu/drm/bridge/Makefile | 1 +
> > > drivers/gpu/drm/bridge/ti-sn65dsi84.c | 488 ++++++++++++++++++++++++++
> > > 4 files changed, 514 insertions(+)
> > > create mode 100644 drivers/gpu/drm/bridge/ti-sn65dsi84.c
> > >
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index 12dd1fff2a39..44750ff7640c 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -5984,6 +5984,12 @@ S: Maintained
> > > F: Documentation/devicetree/bindings/display/ti/
> > > F: drivers/gpu/drm/omapdrm/
> > >
> > > +DRM DRIVERS FOR TI SN65DSI84 DSI TO LVDS BRIDGE
> > > +M: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
> > > +S: Maintained
> > > +F: Documentation/devicetree/bindings/display/bridge/ti,sn65dsi84.yaml
> > > +F: drivers/gpu/drm/bridge/ti-sn65dsi84.c
> > > +
> > > DRM DRIVERS FOR V3D
> > > M: Eric Anholt <eric@xxxxxxxxxx>
> > > S: Supported
> > > diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> > > index e4110d6ca7b3..6494881bffb3 100644
> > > --- a/drivers/gpu/drm/bridge/Kconfig
> > > +++ b/drivers/gpu/drm/bridge/Kconfig
> > > @@ -232,6 +232,25 @@ config DRM_TI_TFP410
> > > help
> > > Texas Instruments TFP410 DVI/HDMI Transmitter driver
> > >
> > > +config DRM_TI_SN65DSI84
> > > + tristate "TI SN65DSI84 DSI to LVDS bridge"
> > > + depends on OF
> > > + select DRM_KMS_HELPER
> > > + select REGMAP_I2C
> > > + select DRM_PANEL
> > > + select DRM_MIPI_DSI
> > > + help
> > > + Texas Instruments SN65DSI84 Single Channel DSI to Dual-link LVDS
> > > + bridge driver.
> > > +
> > > + Bridge decodes MIPI DSI 18bpp RGB666 and 240bpp RG888 packets and
> > > + converts the formatted video data stream to a FlatLink compatible
> > > + LVDS output operating at pixel clocks operating from 25 MHx to
> > > + 154 MHz.
> > > +
> > > + SN65DSI84 offers a Dual-Link LVDS, Single-Link LVDS interface with
> > > + four data lanes per link.
> > > +
> > > config DRM_TI_SN65DSI86
> > > tristate "TI SN65DSI86 DSI to eDP bridge"
> > > depends on OF
> > > diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> > > index 86e7acc76f8d..3906052ef639 100644
> > > --- a/drivers/gpu/drm/bridge/Makefile
> > > +++ b/drivers/gpu/drm/bridge/Makefile
> > > @@ -20,6 +20,7 @@ obj-$(CONFIG_DRM_TOSHIBA_TC358767) += tc358767.o
> > > obj-$(CONFIG_DRM_TOSHIBA_TC358768) += tc358768.o
> > > obj-$(CONFIG_DRM_TOSHIBA_TC358775) += tc358775.o
> > > obj-$(CONFIG_DRM_I2C_ADV7511) += adv7511/
> > > +obj-$(CONFIG_DRM_TI_SN65DSI84) += ti-sn65dsi84.o
> > > obj-$(CONFIG_DRM_TI_SN65DSI86) += ti-sn65dsi86.o
> > > obj-$(CONFIG_DRM_TI_TFP410) += ti-tfp410.o
> > > obj-$(CONFIG_DRM_TI_TPD12S015) += ti-tpd12s015.o
> > > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi84.c b/drivers/gpu/drm/bridge/ti-sn65dsi84.c
> > > new file mode 100644
> > > index 000000000000..3ed1f9a7d898
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi84.c
> > > @@ -0,0 +1,488 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Copyright (c) 2021 Engicam srl
> > > + * Copyright (C) 2021 Amarula Solutions(India)
> > > + * Author: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
> > > + */
> > > +
> > > +#include <drm/drm_of.h>
> > > +#include <drm/drm_panel.h>
> > > +#include <drm/drm_print.h>
> > > +#include <drm/drm_mipi_dsi.h>
> > > +
> > > +#include <linux/delay.h>
> > > +#include <linux/gpio/consumer.h>
> > > +#include <linux/i2c.h>
> > > +#include <linux/module.h>
> > > +#include <linux/regmap.h>
> > > +
> > > +/* sn65dsi84 registers */
> > > +#define SN65DSI_SOFT_RESET 0x09
> > > +#define SN65DSI_LVDS_CLK 0x0a
> > > +#define SN65DSI_CLK_DIV 0x0b
> > > +#define SN65DSI_CLK_PLL 0x0d
> > > +#define SN65DSI_DSI_CFG 0x10
> > > +#define SN65DSI_DSI_CLK_EQ 0x11
> > > +#define SN65DSI_DSI_CLK_RANGE 0x12
> > > +#define SN65DSI_LVDS_MODE 0x18
> > > +#define SN65DSI_CHA_LINE_LO 0x20
> > > +#define SN65DSI_CHA_LINE_HI 0x21
> > > +#define SN65DSI_CHA_VIRT_LO 0x24
> > > +#define SN65DSI_CHA_VIRT_HI 0x25
> > > +#define SN65DSI_CHA_SYNC_DELAY_LO 0x28
> > > +#define SN65DSI_CHA_SYNC_DELAY_HI 0x29
> > > +#define SN65DSI_CHA_HSYNC_WIDTH_LO 0x2c
> > > +#define SN65DSI_CHA_HSYNC_WIDTH_HI 0x2d
> > > +#define SN65DSI_CHA_VSYNC_WIDTH_LO 0x30
> > > +#define SN65DSI_CHA_VSYNC_WIDTH_HI 0x31
> > > +#define SN65DSI_CHA_HBACK_PORCH 0x34
> > > +#define SN65DSI_CHA_VBACK_PORCH 0x36
> > > +#define SN65DSI_CHA_HFRONT_PORCH 0x38
> > > +#define SN65DSI_CHA_VFRONT_PORCH 0x3a
> > > +#define SN65DSI_CHA_ERR 0xe5
> > > +
> > > +/* sn65dsi register bits */
> > > +#define SN65DSI_RESET_EN BIT(0)
> > > +#define SN65DSI_PLL_EN BIT(0)
> > > +#define SN65DSI_LVDS_CLK_MASK GENMASK(3, 1)
> > > +#define SN65DSI_LVDS_CLK_SHIFT 1
> > > +#define SN65DSI_LVDS_CLK_SRC_DSI BIT(0)
> > > +#define SN65DSI_CLK_DIV_MASK GENMASK(7, 3)
> > > +#define SN65DSI_CLK_DIV_SHIFT 3
> > > +#define SN65DSI_DSI_LANE_MASK GENMASK(4, 3)
> > > +#define SN65DSI_DSI_LANE_SHIFT 3
> > > +#define SN65DSI_LVDS_LINK_CFG BIT(4)
> > > +#define SN65DSI_LVDS_CHA_24BPP BIT(3)
> > > +#define SN65DSI_CHA_LOW_SYNC_DELAY 0x20
> > > +#define SN65DSI_CHA_HIGH_SYNC_DELAY 0x00
> > > +
> > > +struct sn65dsi {
> > > + struct device *dev;
> > > + struct drm_bridge bridge;
> > > + struct drm_bridge *panel_bridge;
> > > +
> > > + struct device_node *host_node;
> > > + struct mipi_dsi_device *dsi;
> > > + u8 dsi_lanes;
> > > +
> > > + struct regmap *regmap;
> > > + struct gpio_desc *enable;
> > > +};
> > > +
> > > +static const struct regmap_config sn65dsi_regmap_config = {
> > > + .reg_bits = 8,
> > > + .val_bits = 8,
> > > + .max_register = SN65DSI_CHA_ERR,
> > > + .name = "sn65dsi",
> > > + .cache_type = REGCACHE_RBTREE,
> > > +};
> > > +
> > > +static inline struct sn65dsi *bridge_to_sn65dsi(struct drm_bridge *bridge)
> > > +{
> > > + return container_of(bridge, struct sn65dsi, bridge);
> > > +}
> > > +
> > > +static struct drm_display_mode *bridge_to_mode(struct drm_bridge *bridge)
> > > +{
> > > + return &bridge->encoder->crtc->state->mode;
> > > +}
> > > +
> > > +static void sn65dsi_setup_channels(struct sn65dsi *sn,
> > > + struct drm_display_mode *mode)
> > > +{
> > > + u32 hsync_len, hfront_porch, hback_porch;
> > > + u32 vsync_len, vfront_porch, vback_porch;
> > > +
> > > + hfront_porch = mode->hsync_start - mode->hdisplay;
> > > + hsync_len = mode->hsync_end - mode->hsync_start;
> > > + hback_porch = mode->htotal - mode->hsync_end;
> > > +
> > > + vfront_porch = mode->vsync_start - mode->vdisplay;
> > > + vsync_len = mode->vsync_end - mode->vsync_start;
> > > + vback_porch = mode->vtotal - mode->vsync_end;
> > > +
> > > + /* cha, lower 8-bits of hdisplay */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_LINE_LO, mode->hdisplay & 0xff);
> > > +
> > > + msleep(10);
> > > +
> >
> > I don't find any reason for those msleep. I don't have on my setup
> > with the same bridge
>
> As recommended by 8.2.2.1 Example Script from the datasheet.
>
> https://www.ti.com/product/SN65DSI84
>

Jurat wrap in one function and avoid, multiple msleep. Invesitgate
even if delay_us in regamp can be
used

Michael

> >
> > > + /* cha, upper 4-bits of hdisplay */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_LINE_HI, (mode->hdisplay >> 8) & 0xff);
> > > +
> > > + msleep(10);
> > > +
> > > + /* cha, lower 8-bits of vdisplay */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_VIRT_LO, mode->vdisplay & 0xff);
> > > +
> > > + msleep(10);
> > > +
> > > + /* cha, upper 4-bits of vdisplay */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_VIRT_HI, (mode->vdisplay >> 8) & 0xff);
> > > +
> > > + msleep(10);
> > > +
> > > + /*cha, lower sync delay */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_SYNC_DELAY_LO, SN65DSI_CHA_LOW_SYNC_DELAY);
> > > +
> > > + msleep(10);
> > > +
> > > + /*cha, upper sync delay */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_SYNC_DELAY_HI, SN65DSI_CHA_HIGH_SYNC_DELAY);
> > > +
> > > + msleep(10);
> > > +
> > > + /* cha, lower 8-bits of hsync_len */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_HSYNC_WIDTH_LO, hsync_len & 0xff);
> > > +
> > > + msleep(10);
> > > +
> > > + /* cha, upper 2-bits of hsync_len */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_HSYNC_WIDTH_HI, (hsync_len >> 8) & 0xff);
> > > +
> > > + msleep(10);
> > > +
> > > + /* cha, lower 8-bits of vsync_len */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_VSYNC_WIDTH_LO, vsync_len & 0xff);
> > > +
> > > + msleep(10);
> > > +
> > > + /* cha, upper 2-bits of vsync_len */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_VSYNC_WIDTH_HI, (vsync_len >> 8) & 0xff);
> > > +
> > > + msleep(10);
> > > +
> > > + /* cha, hback_porch */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_HBACK_PORCH, hback_porch & 0xff);
> > > +
> > > + msleep(10);
> > > +
> > > + /* cha, vback_porch */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_VBACK_PORCH, vback_porch & 0xff);
> > > +
> > > + msleep(10);
> > > +
> > > + /* cha, hfront_porch */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_HFRONT_PORCH, hfront_porch & 0xff);
> > > +
> > > + msleep(10);
> > > +
> > > + /* cha, vfront_porch */
> > > + regmap_write(sn->regmap, SN65DSI_CHA_VFRONT_PORCH, vfront_porch & 0xff);
> > > +
> > > + msleep(10);
> > > +}
> > > +
> > > +static int sn65dsi_get_clk_range(int min, int max, unsigned long clock,
> > > + unsigned long start, unsigned long diff)
> > > +{
> > > + unsigned long next;
> > > + int i;
> > > +
> > > + for (i = min; i <= max; i++) {
> > > + next = start + diff;
> > > + if (start <= clock && clock < next)
> > > + return i;
> > > +
> > > + start += diff;
> > > + }
> > > +
> > > + return -EINVAL;
> > > +}
> > > +
> > > +static void sn65dsi_enable(struct drm_bridge *bridge)
> > > +{
> > > + struct sn65dsi *sn = bridge_to_sn65dsi(bridge);
> > > + struct drm_display_mode *mode = bridge_to_mode(bridge);
> > > + int bpp = mipi_dsi_pixel_format_to_bpp(sn->dsi->format);
> > > + unsigned int lanes = sn->dsi->lanes;
> > > + unsigned int pixel_clk = mode->clock * 1000;
> > > + unsigned int dsi_clk = pixel_clk * bpp / (lanes * 2);
> > > + unsigned int val;
> > > +
> > > + /* set SOFT_RESET bit */
> > > + regmap_write(sn->regmap, SN65DSI_SOFT_RESET, SN65DSI_RESET_EN);
> > > +
> > > + msleep(10);
> > > +
> > > + /* set PLL_EN bit */
> > > + regmap_write(sn->regmap, SN65DSI_CLK_PLL, 0x0);
> > > +
> > > + msleep(10);
> > > +
> > > + /* setup lvds clock */
> > > + val = sn65dsi_get_clk_range(0, 5, pixel_clk, 25000000, 25000000);
> > > + if (val < 0) {
> > > + DRM_DEV_ERROR(sn->dev, "invalid LVDS clock range %d\n", val);
> > > + return;
> > > + }
> > > +
> > > + regmap_update_bits(sn->regmap, SN65DSI_LVDS_CLK,
> > > + SN65DSI_LVDS_CLK_MASK,
> > > + val << SN65DSI_LVDS_CLK_SHIFT);
> > > +
> > > + regmap_update_bits(sn->regmap, SN65DSI_LVDS_CLK,
> > > + SN65DSI_LVDS_CLK_SRC_DSI,
> > > + SN65DSI_LVDS_CLK_SRC_DSI);
> > > +
> > > + msleep(10);
> > > +
> > > + /* setup bridge clock divider */
> > > + val = (dsi_clk / pixel_clk) - 1;
> > > + regmap_update_bits(sn->regmap, SN65DSI_CLK_DIV,
> > > + SN65DSI_CLK_DIV_MASK,
> > > + val << SN65DSI_CLK_DIV_SHIFT);
> > > + msleep(10);
> > > +
> > > + /* configure dsi */
> > > + regmap_update_bits(sn->regmap, SN65DSI_DSI_CFG,
> > > + SN65DSI_DSI_LANE_MASK,
> > > + lanes << SN65DSI_DSI_LANE_SHIFT);
> > > + msleep(10);
> > > +
> >
> > Most of those, look like. I don't know why it does not work without.
> > Where is mention in datasheet?
> >
> > > + /* dsi clock range */
> > > + val = sn65dsi_get_clk_range(8, 100, dsi_clk, 40000000, 5000000);
> > > + if (val < 0) {
> > > + DRM_DEV_ERROR(sn->dev, "invalid DSI clock range %d\n", val);
> > > + return;
> > > + }
> > > +
> > > + regmap_write(sn->regmap, SN65DSI_DSI_CLK_RANGE, val);
> > > +
> > > + msleep(10);
> > > +
> > > + /* setup lvds channels */
> > > + regmap_read(sn->regmap, SN65DSI_LVDS_MODE, &val);
> > > + if (bpp == 24)
> > > + val |= SN65DSI_LVDS_CHA_24BPP;
> > > + regmap_write(sn->regmap, SN65DSI_LVDS_MODE, val);
> > > +
> > > + msleep(10);
> > > +
> > > + /* TODO Channel B required to set up for dual-link LVDS */
> > > + sn65dsi_setup_channels(sn, mode);
> > > +
> >
> > If you are supporting 84 this code can be drop.
>
> Right now the above function is setting up channel A for single-link
> LVDS. 84 support Single and Dual link LVDS.
>
> Jagan.

--
Michael Nazzareno Trimarchi
Amarula Solutions BV
COO Co-Founder
Cruquiuskade 47 Amsterdam 1018 AM NL
T. +31(0)851119172
M. +39(0)3479132170
[`as] https://www.amarulasolutions.com

Next message: Borislav Petkov: "Re: [PATCH v4] x86/mce: Avoid infinite loop for copy from user recovery"
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In reply to: Jagan Teki: "Re: [PATCH 2/2] drm: bridge: Add SN65DSI84 DSI to LVDS bridge"
Next in thread: Laurent Pinchart: "Re: [PATCH 2/2] drm: bridge: Add SN65DSI84 DSI to LVDS bridge"
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