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SubjectRe: [PATCH v2 2/2] drm: bridge: Add SN65DSI84 DSI to LVDS bridge
On Wed, Feb 3, 2021 at 2:51 PM Michael Nazzareno Trimarchi
<michael@amarulasolutions.com> wrote:
>
> Hi
>
> On Wed, Feb 3, 2021 at 8:13 AM Jagan Teki <jagan@amarulasolutions.com> 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: Jagan Teki <jagan@amarulasolutions.com>
> > ---
> > Changes for v2:
> > - dropped the mdelays between commands as delays in init script in
> > datasheet is based Aardvark I2C host adaptor.
> > https://e2e.ti.com/support/interface/f/138/t/974276
> >
> > MAINTAINERS | 6 +
> > drivers/gpu/drm/bridge/Kconfig | 19 ++
> > drivers/gpu/drm/bridge/Makefile | 1 +
> > drivers/gpu/drm/bridge/ti-sn65dsi84.c | 457 ++++++++++++++++++++++++++
> > 4 files changed, 483 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@amarulasolutions.com>
> > +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@anholt.net>
> > 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..27a9074db17e
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi84.c
> > @@ -0,0 +1,457 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2021 Engicam srl
> > + * Copyright (C) 2021 Amarula Solutions(India)
> > + * Author: Jagan Teki <jagan@amarulasolutions.com>
> > + */
> > +
> > +#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;
> > +};
>
> I suggest a better name. 3 different families are compatible here

sn65dsi83/84/85 are similar chips. Do you mean ti-sn65dsi8x.c it can
confuse with exiting ti-sn65dsi86.c, doesn't it?

> > +
> > +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);
> > +
> > + /* cha, upper 4-bits of hdisplay */
> > + regmap_write(sn->regmap, SN65DSI_CHA_LINE_HI, (mode->hdisplay >> 8) & 0xff);
> > +
> > + /* cha, lower 8-bits of vdisplay */
> > + regmap_write(sn->regmap, SN65DSI_CHA_VIRT_LO, mode->vdisplay & 0xff);
> > +
> > + /* cha, upper 4-bits of vdisplay */
> > + regmap_write(sn->regmap, SN65DSI_CHA_VIRT_HI, (mode->vdisplay >> 8) & 0xff);
> > +
> > + /*cha, lower sync delay */
> > + regmap_write(sn->regmap, SN65DSI_CHA_SYNC_DELAY_LO, SN65DSI_CHA_LOW_SYNC_DELAY);
> > +
> > + /*cha, upper sync delay */
> > + regmap_write(sn->regmap, SN65DSI_CHA_SYNC_DELAY_HI, SN65DSI_CHA_HIGH_SYNC_DELAY);
> > +
> > + /* cha, lower 8-bits of hsync_len */
> > + regmap_write(sn->regmap, SN65DSI_CHA_HSYNC_WIDTH_LO, hsync_len & 0xff);
> > +
> > + /* cha, upper 2-bits of hsync_len */
> > + regmap_write(sn->regmap, SN65DSI_CHA_HSYNC_WIDTH_HI, (hsync_len >> 8) & 0xff);
> > +
> > + /* cha, lower 8-bits of vsync_len */
> > + regmap_write(sn->regmap, SN65DSI_CHA_VSYNC_WIDTH_LO, vsync_len & 0xff);
> > +
> > + /* cha, upper 2-bits of vsync_len */
> > + regmap_write(sn->regmap, SN65DSI_CHA_VSYNC_WIDTH_HI, (vsync_len >> 8) & 0xff);
> > +
> > + /* cha, hback_porch */
> > + regmap_write(sn->regmap, SN65DSI_CHA_HBACK_PORCH, hback_porch & 0xff);
> > +
> > + /* cha, vback_porch */
> > + regmap_write(sn->regmap, SN65DSI_CHA_VBACK_PORCH, vback_porch & 0xff);
> > +
> > + /* cha, hfront_porch */
> > + regmap_write(sn->regmap, SN65DSI_CHA_HFRONT_PORCH, hfront_porch & 0xff);
> > +
> > + /* cha, vfront_porch */
> > + regmap_write(sn->regmap, SN65DSI_CHA_VFRONT_PORCH, vfront_porch & 0xff);
> > +}
> > +
> > +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;
> > +
> > + /* reset SOFT_RESET bit */
> > + regmap_write(sn->regmap, SN65DSI_SOFT_RESET, 0x0);
> > +
> > + msleep(10);
> > +
> > + /* reset 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);
> > +
> > + /* 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);
> > +
> > + /* configure dsi */
> > + regmap_update_bits(sn->regmap, SN65DSI_DSI_CFG,
> > + SN65DSI_DSI_LANE_MASK,
> > + lanes << SN65DSI_DSI_LANE_SHIFT);
> > +
> > + /* 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);
> > +
> > + /* 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);
>
> This register should have even how data are packed by dsi. There are two mode
> mode 1 and mode 2.

You mean BIT:3, 2 CHA_24BPP_MODE, CHB_24BPP_MODE?

The above SN64DSI_LVDS_CHA_24BPP is the same and it is updating CHA
for now as CHB is not supported yet.

>
> > +
> > + /* TODO Channel B required to set up for dual-link LVDS */
> > + sn65dsi_setup_channels(sn, mode);
> > +
> > + /* 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, SN65DSI_PLL_EN);
> > +
> > + msleep(10);
> > +}
> > +
> > +static void sn65dsi_disable(struct drm_bridge *bridge)
> > +{
> > + struct sn65dsi *sn = bridge_to_sn65dsi(bridge);
> > +
> > + /* set PLL_EN bit */
> > + regmap_write(sn->regmap, SN65DSI_CLK_PLL, 0x0);
> > +
> > + msleep(10);
> > +
> > + /* set SOFT_RESET bit */
> > + regmap_write(sn->regmap, SN65DSI_SOFT_RESET, 0x0);
> > +
> > + msleep(10);
>
> Can you point me out the documenation where is written

I can see the sequence pointed in 7.4.3 Initialization Sequence

>
> > +}
> > +
> > +static void sn65dsi_post_disable(struct drm_bridge *bridge)
> > +{
> > + struct sn65dsi *sn = bridge_to_sn65dsi(bridge);
> > +
> > + gpiod_set_value_cansleep(sn->enable, 1);
> > +
> > + msleep(10);
> > +
> > + gpiod_set_value_cansleep(sn->enable, 0);
> > +
> > + msleep(10);
>
> Again is there any description about the reset time in datasheet. If
> so, please point to the section
>
> > +}
> > +
> > +static void sn65dsi_pre_enable(struct drm_bridge *bridge)
> > +{
> > + struct sn65dsi *sn = bridge_to_sn65dsi(bridge);
> > +
> > + gpiod_set_value_cansleep(sn->enable, 0);
> > +
> > + msleep(10);
> > +
> > + gpiod_set_value_cansleep(sn->enable, 1);
> > +
> > + msleep(10);
>
> Ditto
>
> > +}
> > +
> > +static int sn65dsi_attach(struct drm_bridge *bridge, enum drm_bridge_attach_flags flags)
> > +{
> > + struct sn65dsi *sn = bridge_to_sn65dsi(bridge);
> > + struct mipi_dsi_host *host;
> > + struct mipi_dsi_device *dsi;
> > + const struct mipi_dsi_device_info info = { .type = "sn65dsi",
> > + .channel = 0,
> > + .node = NULL,
> > + };
> > + int ret;
> > +
> > + host = of_find_mipi_dsi_host_by_node(sn->host_node);
> > + if (!host) {
> > + DRM_DEV_ERROR(sn->dev, "failed to find dsi host\n");
> > + return -EPROBE_DEFER;
> > + }
> > +
> > + dsi = mipi_dsi_device_register_full(host, &info);
> > + if (IS_ERR(dsi)) {
> > + DRM_DEV_ERROR(sn->dev, "failed to create dsi device\n");
> > + return PTR_ERR(sn->dsi);
> > + }
> > +
> > + sn->dsi = dsi;
> > + dsi->lanes = sn->dsi_lanes;
> > + dsi->format = MIPI_DSI_FMT_RGB888;
> > + dsi->mode_flags = MIPI_DSI_MODE_VIDEO;
> > +
> > + ret = mipi_dsi_attach(dsi);
> > + if (ret) {
> > + DRM_DEV_ERROR(sn->dev, "failed to attach dsi host\n");
> > + goto err_dsi_attach;
> > + }
> > +
> > + return drm_bridge_attach(bridge->encoder, sn->panel_bridge,
> > + &sn->bridge, flags);
> > +
> > +err_dsi_attach:
> > + mipi_dsi_device_unregister(dsi);
> > + return ret;
> > +}
> > +
> > +static const struct drm_bridge_funcs sn65dsi_bridge_funcs = {
> > + .attach = sn65dsi_attach,
> > + .pre_enable = sn65dsi_pre_enable,
> > + .enable = sn65dsi_enable,
> > + .disable = sn65dsi_disable,
> > + .post_disable = sn65dsi_post_disable,
> > +};
> > +
> > +static int sn65dsi_parse_dt(struct sn65dsi *sn)
> > +{
> > + struct device *dev = sn->dev;
> > + struct device_node *endpoint, *parent;
> > + struct property *prop;
> > + struct drm_panel *panel;
> > + int len = 0;
> > + int ret;
> > +
> > + sn->enable = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
> > + if (IS_ERR(sn->enable)) {
> > + DRM_DEV_ERROR(dev, "failed to get enable gpio\n");
> > + return PTR_ERR(sn->enable);
> > + }
> > +
> > + ret = drm_of_find_panel_or_bridge(dev->of_node, 1, 0, &panel, NULL);
> > + if (ret < 0)
> > + return ret;
> > + if (!panel)
> > + return -ENODEV;
> > +
> > + sn->panel_bridge = devm_drm_panel_bridge_add(dev, panel);
> > + if (IS_ERR(sn->panel_bridge))
> > + return PTR_ERR(sn->panel_bridge);
> > +
> > + /*
> > + * To get the data-lanes of dsi, we need to access the port1 of dsi_out
> > + * from the port0 of bridge.
> > + */
> > + endpoint = of_graph_get_endpoint_by_regs(dev->of_node, 0, -1);
> > + if (endpoint) {
>
> What is happen if you have no endpoint should not already fail?

You mean for !endpoint case? it would return -EINVAL. the next lanes
cases would return for no endpoint cases.

Jagan.
--
Jagan Teki,
Amarula Solutions India Pvt. Ltd.
Co-Founder & Embedded Linux Architect
405/E-Block, Sri Lakshmi Shubham Arcade, Chandanagar, Hyderabad - 500050, India
M. (+91) 910 009 0959
[`as] http://www.amarulasolutions.com

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