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Message-ID: <CAPVz0n0dZqbLknNqf3g0T0Wc2HiQMR2zwius=XWe-wL+znwKbA@mail.gmail.com>
Date: Wed, 19 Feb 2025 21:06:53 +0200
From: Svyatoslav Ryhel <clamor95@...il.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: Andrzej Hajda <andrzej.hajda@...el.com>, Neil Armstrong <neil.armstrong@...aro.org>,
Robert Foss <rfoss@...nel.org>, Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard <mripard@...nel.org>,
Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>,
dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] drm: bridge: Add support for Solomon SSD2825
RGB/DSI bridge
вт, 18 лют. 2025 р. о 14:31 Dmitry Baryshkov <dmitry.baryshkov@...aro.org> пише:
>
> On Mon, Feb 17, 2025 at 04:09:10PM +0200, Svyatoslav Ryhel wrote:
> > SSD2825 is a cost-effective MIPI Bridge Chip solution targeting mainly
> > smartphones. It can convert 24bit RGB interface into 4-lane MIPI-DSI
> > interface to drive display modules of up to 800 x 1366, while supporting
> > AMOLED, a-si LCD or LTPS panel technologies for smartphone applications.
> >
> > Signed-off-by: Svyatoslav Ryhel <clamor95@...il.com>
> > ---
> > drivers/gpu/drm/bridge/Kconfig | 14 +
> > drivers/gpu/drm/bridge/Makefile | 1 +
> > drivers/gpu/drm/bridge/ssd2825.c | 824 +++++++++++++++++++++++++++++++
> > 3 files changed, 839 insertions(+)
> > create mode 100644 drivers/gpu/drm/bridge/ssd2825.c
> >
> > diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> > index 6b4664d91faa..a6eca3aef258 100644
> > --- a/drivers/gpu/drm/bridge/Kconfig
> > +++ b/drivers/gpu/drm/bridge/Kconfig
> > @@ -306,6 +306,20 @@ config DRM_SIMPLE_BRIDGE
> > Support for non-programmable DRM bridges, such as ADI ADV7123, TI
> > THS8134 and THS8135 or passive resistor ladder DACs.
> >
> > +config DRM_SOLOMON_SSD2825
> > + tristate "SSD2825 RGB/DSI bridge"
> > + depends on SPI_MASTER && OF
> > + select DRM_MIPI_DSI
> > + select DRM_KMS_HELPER
> > + select DRM_PANEL
> > + select VIDEOMODE_HELPERS
> > + help
> > + Say Y here if you want support for the Solomon SSD2825 RGB/DSI
> > + SPI bridge driver.
> > +
> > + Say M here if you want to support this hardware as a module.
> > + The module will be named "solomon-ssd2825".
> > +
> > config DRM_THINE_THC63LVD1024
> > tristate "Thine THC63LVD1024 LVDS decoder bridge"
> > depends on OF
> > diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> > index 97304b429a53..c621ab3fa3a9 100644
> > --- a/drivers/gpu/drm/bridge/Makefile
> > +++ b/drivers/gpu/drm/bridge/Makefile
> > @@ -23,6 +23,7 @@ obj-$(CONFIG_DRM_SIL_SII8620) += sil-sii8620.o
> > obj-$(CONFIG_DRM_SII902X) += sii902x.o
> > obj-$(CONFIG_DRM_SII9234) += sii9234.o
> > obj-$(CONFIG_DRM_SIMPLE_BRIDGE) += simple-bridge.o
> > +obj-$(CONFIG_DRM_SOLOMON_SSD2825) += ssd2825.o
> > obj-$(CONFIG_DRM_THINE_THC63LVD1024) += thc63lvd1024.o
> > obj-$(CONFIG_DRM_TOSHIBA_TC358762) += tc358762.o
> > obj-$(CONFIG_DRM_TOSHIBA_TC358764) += tc358764.o
> > diff --git a/drivers/gpu/drm/bridge/ssd2825.c b/drivers/gpu/drm/bridge/ssd2825.c
> > new file mode 100644
> > index 000000000000..cc6f5d480812
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/ssd2825.c
> > @@ -0,0 +1,824 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +#include <linux/clk.h>
> > +#include <linux/delay.h>
> > +#include <linux/device.h>
> > +#include <linux/err.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/mod_devicetable.h>
> > +#include <linux/mutex.h>
> > +#include <linux/of.h>
> > +#include <linux/regulator/consumer.h>
> > +#include <linux/spi/spi.h>
> > +
> > +#include <drm/drm_atomic_helper.h>
> > +#include <drm/drm_bridge.h>
> > +#include <drm/drm_drv.h>
> > +#include <drm/drm_mipi_dsi.h>
> > +#include <drm/drm_of.h>
> > +#include <drm/drm_panel.h>
> > +#include <video/mipi_display.h>
> > +#include <video/videomode.h>
> > +
> > +#define SSD2825_DEVICE_ID_REG 0xb0
> > +#define SSD2825_RGB_INTERFACE_CTRL_REG_1 0xb1
> > +#define SSD2825_RGB_INTERFACE_CTRL_REG_2 0xb2
> > +#define SSD2825_RGB_INTERFACE_CTRL_REG_3 0xb3
> > +#define SSD2825_RGB_INTERFACE_CTRL_REG_4 0xb4
> > +#define SSD2825_RGB_INTERFACE_CTRL_REG_5 0xb5
> > +#define SSD2825_RGB_INTERFACE_CTRL_REG_6 0xb6
> > +#define SSD2825_NON_BURST_EV BIT(2)
> > +#define SSD2825_BURST BIT(3)
> > +#define SSD2825_PCKL_HIGH BIT(13)
> > +#define SSD2825_HSYNC_HIGH BIT(14)
> > +#define SSD2825_VSYNC_HIGH BIT(15)
> > +#define SSD2825_CONFIGURATION_REG 0xb7
> > +#define SSD2825_CONF_REG_HS BIT(0)
> > +#define SSD2825_CONF_REG_CKE BIT(1)
> > +#define SSD2825_CONF_REG_SLP BIT(2)
> > +#define SSD2825_CONF_REG_VEN BIT(3)
> > +#define SSD2825_CONF_REG_HCLK BIT(4)
> > +#define SSD2825_CONF_REG_CSS BIT(5)
> > +#define SSD2825_CONF_REG_DCS BIT(6)
> > +#define SSD2825_CONF_REG_REN BIT(7)
> > +#define SSD2825_CONF_REG_ECD BIT(8)
> > +#define SSD2825_CONF_REG_EOT BIT(9)
> > +#define SSD2825_CONF_REG_LPE BIT(10)
> > +#define SSD2825_VC_CTRL_REG 0xb8
> > +#define SSD2825_PLL_CTRL_REG 0xb9
> > +#define SSD2825_PLL_CONFIGURATION_REG 0xba
> > +#define SSD2825_CLOCK_CTRL_REG 0xbb
> > +#define SSD2825_PACKET_SIZE_CTRL_REG_1 0xbc
> > +#define SSD2825_PACKET_SIZE_CTRL_REG_2 0xbd
> > +#define SSD2825_PACKET_SIZE_CTRL_REG_3 0xbe
> > +#define SSD2825_PACKET_DROP_REG 0xbf
> > +#define SSD2825_OPERATION_CTRL_REG 0xc0
> > +#define SSD2825_MAX_RETURN_SIZE_REG 0xc1
> > +#define SSD2825_RETURN_DATA_COUNT_REG 0xc2
> > +#define SSD2825_ACK_RESPONSE_REG 0xc3
> > +#define SSD2825_LINE_CTRL_REG 0xc4
> > +#define SSD2825_INTERRUPT_CTRL_REG 0xc5
> > +#define SSD2825_INTERRUPT_STATUS_REG 0xc6
> > +#define SSD2825_ERROR_STATUS_REG 0xc7
> > +#define SSD2825_DATA_FORMAT_REG 0xc8
> > +#define SSD2825_DELAY_ADJ_REG_1 0xc9
> > +#define SSD2825_DELAY_ADJ_REG_2 0xca
> > +#define SSD2825_DELAY_ADJ_REG_3 0xcb
> > +#define SSD2825_DELAY_ADJ_REG_4 0xcc
> > +#define SSD2825_DELAY_ADJ_REG_5 0xcd
> > +#define SSD2825_DELAY_ADJ_REG_6 0xce
> > +#define SSD2825_HS_TX_TIMER_REG_1 0xcf
> > +#define SSD2825_HS_TX_TIMER_REG_2 0xd0
> > +#define SSD2825_LP_RX_TIMER_REG_1 0xd1
> > +#define SSD2825_LP_RX_TIMER_REG_2 0xd2
> > +#define SSD2825_TE_STATUS_REG 0xd3
> > +#define SSD2825_SPI_READ_REG 0xd4
> > +#define SSD2825_SPI_READ_REG_RESET 0xfa
> > +#define SSD2825_PLL_LOCK_REG 0xd5
> > +#define SSD2825_TEST_REG 0xd6
> > +#define SSD2825_TE_COUNT_REG 0xd7
> > +#define SSD2825_ANALOG_CTRL_REG_1 0xd8
> > +#define SSD2825_ANALOG_CTRL_REG_2 0xd9
> > +#define SSD2825_ANALOG_CTRL_REG_3 0xda
> > +#define SSD2825_ANALOG_CTRL_REG_4 0xdb
> > +#define SSD2825_INTERRUPT_OUT_CTRL_REG 0xdc
> > +#define SSD2825_RGB_INTERFACE_CTRL_REG_7 0xdd
> > +#define SSD2825_LANE_CONFIGURATION_REG 0xde
> > +#define SSD2825_DELAY_ADJ_REG_7 0xdf
> > +#define SSD2825_INPUT_PIN_CTRL_REG_1 0xe0
> > +#define SSD2825_INPUT_PIN_CTRL_REG_2 0xe1
> > +#define SSD2825_BIDIR_PIN_CTRL_REG_1 0xe2
> > +#define SSD2825_BIDIR_PIN_CTRL_REG_2 0xe3
> > +#define SSD2825_BIDIR_PIN_CTRL_REG_3 0xe4
> > +#define SSD2825_BIDIR_PIN_CTRL_REG_4 0xe5
> > +#define SSD2825_BIDIR_PIN_CTRL_REG_5 0xe6
> > +#define SSD2825_BIDIR_PIN_CTRL_REG_6 0xe7
> > +#define SSD2825_BIDIR_PIN_CTRL_REG_7 0xe8
> > +#define SSD2825_CABC_BRIGHTNESS_CTRL_REG_1 0xe9
> > +#define SSD2825_CABC_BRIGHTNESS_CTRL_REG_2 0xea
> > +#define SSD2825_CABC_BRIGHTNESS_STATUS_REG 0xeb
> > +#define SSD2825_READ_REG 0xff
> > +
> > +#define SSD2825_COM_BYTE 0x00
> > +#define SSD2825_DAT_BYTE 0x01
> > +
> > +#define SSD2828_LP_CLOCK_DIVIDER(n) (((n) - 1) & 0x3f)
> > +#define SSD2825_LP_MIN_CLK 5000 /* KHz */
> > +#define SSD2825_REF_MIN_CLK 2000 /* KHz */
> > +
> > +static const struct regulator_bulk_data ssd2825_supplies[] = {
> > + { .supply = "dvdd" },
> > + { .supply = "avdd" },
> > + { .supply = "vddio" },
> > +};
> > +
> > +struct ssd2825_dsi_output {
> > + struct mipi_dsi_device *dev;
> > + struct drm_panel *panel;
> > + struct drm_bridge *bridge;
> > +};
> > +
> > +struct ssd2825_priv {
> > + struct spi_device *spi;
> > + struct device *dev;
> > +
> > + struct gpio_desc *reset_gpio;
> > + struct regulator_bulk_data *supplies;
> > +
> > + struct clk *tx_clk;
> > +
> > + int enabled;
> > +
> > + struct mipi_dsi_host dsi_host;
> > + struct drm_bridge bridge;
> > + struct ssd2825_dsi_output output;
> > +
> > + struct mutex mlock; /* for host transfer operations */
> > +
> > + u32 pd_lines; /* number of Parallel Port Input Data Lines */
> > + u32 dsi_lanes; /* number of DSI Lanes */
> > +
> > + /* Parameters for PLL programming */
> > + u32 pll_freq_kbps; /* PLL in kbps */
> > + u32 nibble_freq_khz; /* PLL div by 4 */
> > +
> > + u32 hzd; /* HS Zero Delay in ns*/
> > + u32 hpd; /* HS Prepare Delay is ns */
> > +};
> > +
> > +static inline struct ssd2825_priv *dsi_host_to_ssd2825(struct mipi_dsi_host
> > + *host)
> > +{
> > + return container_of(host, struct ssd2825_priv, dsi_host);
> > +}
> > +
> > +static inline struct ssd2825_priv *bridge_to_ssd2825(struct drm_bridge
> > + *bridge)
> > +{
> > + return container_of(bridge, struct ssd2825_priv, bridge);
> > +}
> > +
> > +static int ssd2825_write_raw(struct ssd2825_priv *priv, u8 high_byte, u8 low_byte)
> > +{
> > + struct spi_device *spi = priv->spi;
> > + u8 tx_buf[2];
> > +
> > + /*
> > + * Low byte is the value, high byte defines type of
> > + * write cycle, 0 for command and 1 for data.
> > + */
> > + tx_buf[0] = low_byte;
> > + tx_buf[1] = high_byte;
> > +
> > + return spi_write(spi, tx_buf, 2);
> > +}
> > +
> > +static int ssd2825_write_reg(struct ssd2825_priv *priv, u8 reg, u16 command)
> > +{
> > + u8 datal = (command & 0x00FF);
> > + u8 datah = (command & 0xFF00) >> 8;
> > + int ret;
> > +
> > + /* Command write cycle */
> > + ret = ssd2825_write_raw(priv, SSD2825_COM_BYTE, reg);
> > + if (ret)
> > + return ret;
> > +
> > + /* Data write cycle bits 7-0 */
> > + ret = ssd2825_write_raw(priv, SSD2825_DAT_BYTE, datal);
> > + if (ret)
> > + return ret;
> > +
> > + /* Data write cycle bits 15-8 */
> > + ret = ssd2825_write_raw(priv, SSD2825_DAT_BYTE, datah);
> > + if (ret)
> > + return ret;
> > +
> > + return 0;
> > +}
> > +
> > +static int ssd2825_write_dsi(struct ssd2825_priv *priv, const u8 *command, int len)
> > +{
> > + int ret, i;
> > +
> > + ret = ssd2825_write_reg(priv, SSD2825_PACKET_SIZE_CTRL_REG_1, len);
> > + if (ret)
> > + return ret;
> > +
> > + ret = ssd2825_write_raw(priv, SSD2825_COM_BYTE, SSD2825_PACKET_DROP_REG);
> > + if (ret)
> > + return ret;
> > +
> > + for (i = 0; i < len; i++) {
> > + ret = ssd2825_write_raw(priv, SSD2825_DAT_BYTE, command[i]);
> > + if (ret)
> > + return ret;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int ssd2825_read_raw(struct ssd2825_priv *priv, u8 cmd, u16 *data)
> > +{
> > + struct spi_device *spi = priv->spi;
> > + struct spi_message msg;
> > + struct spi_transfer xfer[2];
> > + u8 tx_buf[2];
> > + u8 rx_buf[2];
> > + int ret;
> > +
> > + memset(&xfer, 0, sizeof(xfer));
> > +
> > + tx_buf[1] = (cmd & 0xFF00) >> 8;
> > + tx_buf[0] = (cmd & 0x00FF);
> > +
> > + xfer[0].tx_buf = tx_buf;
> > + xfer[0].bits_per_word = 9;
> > + xfer[0].len = 2;
> > +
> > + xfer[1].rx_buf = rx_buf;
> > + xfer[1].bits_per_word = 16;
> > + xfer[1].len = 2;
> > +
> > + spi_message_init(&msg);
> > + spi_message_add_tail(&xfer[0], &msg);
> > + spi_message_add_tail(&xfer[1], &msg);
> > +
> > + ret = spi_sync(spi, &msg);
> > + if (ret)
> > + dev_err(&spi->dev, "spi_sync_read failed %d\n", ret);
> > +
> > + *data = rx_buf[1] | (rx_buf[0] << 8);
> > +
> > + return 0;
> > +}
> > +
> > +static int ssd2825_read_reg(struct ssd2825_priv *priv, u8 reg, u16 *data)
> > +{
> > + int ret;
> > +
> > + /* Reset the read register */
> > + ret = ssd2825_write_reg(priv, SSD2825_SPI_READ_REG, SSD2825_SPI_READ_REG_RESET);
> > + if (ret)
> > + return ret;
> > +
> > + /* Push the address to read */
> > + ret = ssd2825_write_raw(priv, SSD2825_COM_BYTE, reg);
> > + if (ret)
> > + return ret;
> > +
> > + /* Perform a reading cycle */
> > + ret = ssd2825_read_raw(priv, SSD2825_SPI_READ_REG_RESET, data);
> > + if (ret)
> > + return ret;
> > +
> > + return 0;
> > +}
> > +
> > +static int ssd2825_dsi_host_attach(struct mipi_dsi_host *host,
> > + struct mipi_dsi_device *dev)
> > +{
> > + struct ssd2825_priv *priv = dsi_host_to_ssd2825(host);
> > + struct drm_bridge *bridge;
> > + struct drm_panel *panel;
> > + struct device_node *ep;
> > + int ret;
> > +
> > + if (dev->lanes > 4) {
> > + dev_err(priv->dev, "unsupported number of data lanes(%u)\n",
> > + dev->lanes);
> > + return -EINVAL;
> > + }
> > +
> > + /*
> > + * ssd2825 supports both Video and Pulse mode, but the driver only
> > + * implements Video (event) mode currently
> > + */
> > + if (!(dev->mode_flags & MIPI_DSI_MODE_VIDEO)) {
> > + dev_err(priv->dev, "Only MIPI_DSI_MODE_VIDEO is supported\n");
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0, &panel,
> > + &bridge);
> > + if (ret)
> > + return ret;
> > +
> > + if (panel) {
> > + bridge = drm_panel_bridge_add_typed(panel,
> > + DRM_MODE_CONNECTOR_DSI);
> > + if (IS_ERR(bridge))
> > + return PTR_ERR(bridge);
> > + }
> > +
> > + priv->output.dev = dev;
> > + priv->output.bridge = bridge;
> > + priv->output.panel = panel;
> > +
> > + priv->dsi_lanes = dev->lanes;
> > +
> > + /* get input ep (port0/endpoint0) */
> > + ret = -EINVAL;
> > + ep = of_graph_get_endpoint_by_regs(host->dev->of_node, 0, 0);
> > + if (ep) {
> > + ret = of_property_read_u32(ep, "bus-width", &priv->pd_lines);
> > +
> > + of_node_put(ep);
> > + }
> > +
> > + if (ret)
> > + priv->pd_lines = mipi_dsi_pixel_format_to_bpp(dev->format);
> > +
> > + drm_bridge_add(&priv->bridge);
> > +
> > + return 0;
> > +}
> > +
> > +static int ssd2825_dsi_host_detach(struct mipi_dsi_host *host,
> > + struct mipi_dsi_device *dev)
> > +{
> > + struct ssd2825_priv *priv = dsi_host_to_ssd2825(host);
> > +
> > + drm_bridge_remove(&priv->bridge);
> > + if (priv->output.panel)
> > + drm_panel_bridge_remove(priv->output.bridge);
> > +
> > + return 0;
> > +}
> > +
> > +static ssize_t ssd2825_dsi_host_transfer(struct mipi_dsi_host *host,
> > + const struct mipi_dsi_msg *msg)
> > +{
> > + struct ssd2825_priv *priv = dsi_host_to_ssd2825(host);
> > + u8 buf = *(u8 *)msg->tx_buf;
> > + u16 config;
> > + int ret;
> > +
> > + if (!priv->enabled) {
> > + dev_err(priv->dev, "Bridge is not enabled\n");
> > + return -ENODEV;
> > + }
>
> Same comment as v1:
>
> No. See include/drm/drm_mipi_dsi.h:
>
> * Also note that those callbacks can be called no matter the state the
> * host is in. Drivers that need the underlying device to be powered to
> * perform these operations will first need to make sure it's been
> * properly enabled.
>
> > +
> > + if (msg->rx_len) {
> > + dev_warn(priv->dev, "MIPI rx is not supported\n");
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + mutex_lock(&priv->mlock);
>
> guard(mutex)(&priv->mlock); would simplify the code here.
>
> > +
> > + ret = ssd2825_read_reg(priv, SSD2825_CONFIGURATION_REG, &config);
> > + if (ret)
> > + goto out_unlock;
> > +
> > + switch (msg->type) {
> > + case MIPI_DSI_DCS_SHORT_WRITE:
> > + case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
> > + case MIPI_DSI_DCS_LONG_WRITE:
> > + config |= SSD2825_CONF_REG_DCS;
> > + break;
> > + case MIPI_DSI_GENERIC_SHORT_WRITE_0_PARAM:
> > + case MIPI_DSI_GENERIC_SHORT_WRITE_1_PARAM:
> > + case MIPI_DSI_GENERIC_SHORT_WRITE_2_PARAM:
> > + case MIPI_DSI_GENERIC_LONG_WRITE:
> > + config &= ~SSD2825_CONF_REG_DCS;
> > + break;
> > + case MIPI_DSI_DCS_READ:
> > + case MIPI_DSI_GENERIC_READ_REQUEST_0_PARAM:
> > + case MIPI_DSI_GENERIC_READ_REQUEST_1_PARAM:
> > + case MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM:
> > + default:
> > + goto out_unlock;
> > + }
> > +
> > + ret = ssd2825_write_reg(priv, SSD2825_CONFIGURATION_REG, config);
> > + if (ret)
> > + goto out_unlock;
> > +
> > + ret = ssd2825_write_reg(priv, SSD2825_VC_CTRL_REG, 0x0000);
> > + if (ret)
> > + goto out_unlock;
> > +
> > + ret = ssd2825_write_dsi(priv, msg->tx_buf, msg->tx_len);
> > + if (ret)
> > + goto out_unlock;
> > +
> > + if (buf == MIPI_DCS_SET_DISPLAY_ON) {
> > + ssd2825_write_reg(priv, SSD2825_CONFIGURATION_REG,
> > + SSD2825_CONF_REG_HS | SSD2825_CONF_REG_VEN |
> > + SSD2825_CONF_REG_DCS | SSD2825_CONF_REG_ECD |
> > + SSD2825_CONF_REG_EOT);
>
> From v1:
>
> Most of these flags should be set depending on the
> mipi_dsi_device.mode_flags.
>
> > + ssd2825_write_reg(priv, SSD2825_PLL_CTRL_REG, 0x0001);
> > + ssd2825_write_reg(priv, SSD2825_VC_CTRL_REG, 0x0000);
>
> Why? Why do you need this special handling for the
> MIPI_DCS_SET_DISPLAY_ON? Why can't it just go to .atomic_enable()?
>
> > + }
> > +
> > +out_unlock:
> > + mutex_unlock(&priv->mlock);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct mipi_dsi_host_ops ssd2825_dsi_host_ops = {
> > + .attach = ssd2825_dsi_host_attach,
> > + .detach = ssd2825_dsi_host_detach,
> > + .transfer = ssd2825_dsi_host_transfer,
> > +};
> > +
> > +static void ssd2825_hw_reset(struct ssd2825_priv *priv)
> > +{
> > + gpiod_set_value_cansleep(priv->reset_gpio, 1);
> > + usleep_range(5000, 6000);
> > + gpiod_set_value_cansleep(priv->reset_gpio, 0);
> > + usleep_range(5000, 6000);
> > +}
> > +
> > +/*
> > + * PLL configuration register settings.
> > + *
> > + * See the "PLL Configuration Register Description" in the SSD2825 datasheet.
> > + */
> > +static u16 construct_pll_config(struct ssd2825_priv *priv,
> > + u32 desired_pll_freq_kbps, u32 reference_freq_khz)
> > +{
> > + u32 div_factor = 1, mul_factor, fr = 0;
> > +
> > + while (reference_freq_khz / (div_factor + 1) >= SSD2825_REF_MIN_CLK)
> > + div_factor++;
> > + if (div_factor > 31)
> > + div_factor = 31;
> > +
> > + mul_factor = DIV_ROUND_UP(desired_pll_freq_kbps * div_factor,
> > + reference_freq_khz);
> > +
> > + priv->pll_freq_kbps = reference_freq_khz * mul_factor / div_factor;
> > + priv->nibble_freq_khz = priv->pll_freq_kbps / 4;
> > +
> > + if (priv->pll_freq_kbps >= 501000)
> > + fr = 3;
> > + else if (priv->pll_freq_kbps >= 251000)
> > + fr = 2;
> > + else if (priv->pll_freq_kbps >= 126000)
> > + fr = 1;
> > +
> > + return (fr << 14) | (div_factor << 8) | mul_factor;
> > +}
> > +
> > +static u32 ssd2825_to_ns(u32 khz)
> > +{
> > + return (1000 * 1000 / khz);
> > +}
> > +
> > +static int ssd2825_setup_pll(struct ssd2825_priv *priv,
> > + const struct drm_display_mode *mode)
> > +{
> > + u16 pll_config, lp_div;
> > + u32 nibble_delay, pclk_mult, tx_freq_khz;
> > + u8 hzd, hpd;
> > +
> > + tx_freq_khz = clk_get_rate(priv->tx_clk) / 1000;
> > + if (!tx_freq_khz)
> > + tx_freq_khz = SSD2825_REF_MIN_CLK;
> > +
> > + pclk_mult = priv->pd_lines / priv->dsi_lanes + 1;
> > + pll_config = construct_pll_config(priv, pclk_mult * mode->clock,
> > + tx_freq_khz);
> > +
> > + lp_div = priv->pll_freq_kbps / (SSD2825_LP_MIN_CLK * 8);
> > +
> > + nibble_delay = ssd2825_to_ns(priv->nibble_freq_khz);
> > +
> > + hzd = priv->hzd / nibble_delay;
> > + hpd = (priv->hpd - 4 * nibble_delay) / nibble_delay;
> > +
> > + /* Disable PLL */
> > + ssd2825_write_reg(priv, SSD2825_PLL_CTRL_REG, 0x0000);
> > + ssd2825_write_reg(priv, SSD2825_LINE_CTRL_REG, 0x0001);
> > +
> > + /* Set delays */
> > + dev_dbg(priv->dev, "SSD2825_DELAY_ADJ_REG_1 0x%x\n", (hzd << 8) | hpd);
>
> From v1:
>
> drm_dbg_driver() ?
>
>
> > + ssd2825_write_reg(priv, SSD2825_DELAY_ADJ_REG_1, (hzd << 8) | hpd);
> > +
> > + /* Set PLL coeficients */
> > + dev_dbg(priv->dev, "SSD2825_PLL_CONFIGURATION_REG 0x%x\n", pll_config);
> > + ssd2825_write_reg(priv, SSD2825_PLL_CONFIGURATION_REG, pll_config);
> > +
> > + /* Clock Control Register */
> > + dev_dbg(priv->dev, "SSD2825_CLOCK_CTRL_REG 0x%x\n",
> > + SSD2828_LP_CLOCK_DIVIDER(lp_div));
> > + ssd2825_write_reg(priv, SSD2825_CLOCK_CTRL_REG,
> > + SSD2828_LP_CLOCK_DIVIDER(lp_div));
> > +
> > + /* Enable PLL */
> > + ssd2825_write_reg(priv, SSD2825_PLL_CTRL_REG, 0x0001);
> > + ssd2825_write_reg(priv, SSD2825_VC_CTRL_REG, 0);
> > +
> > + return 0;
> > +}
> > +
> > +static void ssd2825_bridge_atomic_pre_enable(struct drm_bridge *bridge,
> > + struct drm_bridge_state *old_bridge_state)
> > +{
> > + struct ssd2825_priv *priv = bridge_to_ssd2825(bridge);
> > + int ret;
> > +
> > + if (priv->enabled)
> > + return;
> > +
> > + /* Power Sequence */
> > + ret = clk_prepare_enable(priv->tx_clk);
> > + if (ret < 0)
> > + dev_err(priv->dev, "error enabling tx_clk (%d)\n", ret);
> > +
> > + ret = regulator_bulk_enable(ARRAY_SIZE(ssd2825_supplies), priv->supplies);
> > + if (ret < 0)
> > + dev_err(priv->dev, "error enabling regulators (%d)\n", ret);
> > +
> > + usleep_range(1000, 2000);
> > +
> > + ssd2825_hw_reset(priv);
> > +
> > + priv->enabled = true;
> > +}
> > +
> > +static void ssd2825_bridge_atomic_enable(struct drm_bridge *bridge,
> > + struct drm_bridge_state *old_bridge_state)
> > +{
> > + struct ssd2825_priv *priv = bridge_to_ssd2825(bridge);
> > + struct device *dev = priv->dev;
> > + struct mipi_dsi_device *dsi_dev = priv->output.dev;
> > + struct drm_atomic_state *state = old_bridge_state->base.state;
> > + const struct drm_crtc_state *crtc_state;
> > + const struct drm_display_mode *mode;
> > + struct drm_connector *connector;
> > + struct drm_crtc *crtc;
> > + u32 input_bus_flags = bridge->timings->input_bus_flags;
> > + u16 flags = 0;
> > + u8 pixel_format;
> > +
> > + /* Filter unimplemeted modes before RGB control registers configuration */
> > + if (dsi_dev->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) {
> > + dev_warn_once(dev,
> > + "Non-continuous mode unimplemented, falling back to continuous\n");
> > + dsi_dev->mode_flags &= ~MIPI_DSI_CLOCK_NON_CONTINUOUS;
> > + }
> > +
> > + if (dsi_dev->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
> > + dev_warn_once(dev,
> > + "Burst mode unimplemented, falling back to simple\n");
> > + dsi_dev->mode_flags &= ~MIPI_DSI_MODE_VIDEO_BURST;
> > + }
>
>
> But you have implemented it already, several lines below.
>
> Also such checks should really go to .atomic_check() or
> ssd2825_dsi_host_attach().
>
All those checks do have sense, here me out:
1. atomic_check cannot be used together with mode_fixup, and they both
should contain checks and fixups related to bridge work, not the panel
it drives.
2. ssd2825_bridge_atomic_enable checks knock out modes which are
supported by the device but are not implemented in the driver yet.
They are there since register configuration requites those checks
early
3. ssd2825_dsi_host_attach checks for MIPI_DSI_MODE_VIDEO cause there
might be panels which do not support this mode and each mode is set by
its own bit, hence knocking out unsupported mode does not mean that
supported mode is added.
> > +
> > + /* Perform SW reset */
> > + ssd2825_write_reg(priv, SSD2825_OPERATION_CTRL_REG, 0x0100);
> > +
> > + /* Set pixel format */
> > + switch (dsi_dev->format) {
> > + case MIPI_DSI_FMT_RGB565:
> > + pixel_format = 0x00;
> > + break;
> > + case MIPI_DSI_FMT_RGB666_PACKED:
> > + pixel_format = 0x01;
> > + break;
> > + case MIPI_DSI_FMT_RGB666:
> > + pixel_format = 0x02;
> > + break;
> > + case MIPI_DSI_FMT_RGB888:
> > + default:
> > + pixel_format = 0x03;
> > + break;
> > + }
> > +
> > + connector = drm_atomic_get_new_connector_for_encoder(state,
> > + bridge->encoder);
> > + crtc = drm_atomic_get_new_connector_state(state, connector)->crtc;
> > + crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
> > + mode = &crtc_state->adjusted_mode;
> > +
> > + /* Set panel timings */
> > + ssd2825_write_reg(priv, SSD2825_RGB_INTERFACE_CTRL_REG_1,
> > + ((mode->vtotal - mode->vsync_end) << 8) |
> > + (mode->htotal - mode->hsync_end));
> > + ssd2825_write_reg(priv, SSD2825_RGB_INTERFACE_CTRL_REG_2,
> > + ((mode->vtotal - mode->vsync_start) << 8) |
> > + (mode->htotal - mode->hsync_start));
> > + ssd2825_write_reg(priv, SSD2825_RGB_INTERFACE_CTRL_REG_3,
> > + ((mode->vsync_start - mode->vdisplay) << 8) |
> > + (mode->hsync_start - mode->hdisplay));
> > + ssd2825_write_reg(priv, SSD2825_RGB_INTERFACE_CTRL_REG_4, mode->hdisplay);
> > + ssd2825_write_reg(priv, SSD2825_RGB_INTERFACE_CTRL_REG_5, mode->vdisplay);
> > +
> > + if (mode->flags & DRM_MODE_FLAG_PHSYNC)
> > + flags |= SSD2825_HSYNC_HIGH;
> > +
> > + if (mode->flags & DRM_MODE_FLAG_PVSYNC)
> > + flags |= SSD2825_VSYNC_HIGH;
> > +
> > + if (dsi_dev->mode_flags & MIPI_DSI_MODE_VIDEO)
> > + flags |= SSD2825_NON_BURST_EV;
> > +
> > + if (dsi_dev->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
> > + flags |= SSD2825_BURST;
> > +
> > + if (input_bus_flags & DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE)
> > + flags |= SSD2825_PCKL_HIGH;
> > +
> > + ssd2825_write_reg(priv, SSD2825_RGB_INTERFACE_CTRL_REG_6, flags | pixel_format);
> > + ssd2825_write_reg(priv, SSD2825_LANE_CONFIGURATION_REG, dsi_dev->lanes - 1);
> > + ssd2825_write_reg(priv, SSD2825_TEST_REG, 0x0004);
> > +
> > + /* Call PLL configuration */
> > + ssd2825_setup_pll(priv, mode);
> > +
> > + usleep_range(10000, 11000);
> > +
> > + /* Initial DSI configuration register set */
> > + ssd2825_write_reg(priv, SSD2825_CONFIGURATION_REG,
> > + SSD2825_CONF_REG_CKE | SSD2825_CONF_REG_DCS |
> > + SSD2825_CONF_REG_ECD | SSD2825_CONF_REG_EOT);
> > + ssd2825_write_reg(priv, SSD2825_VC_CTRL_REG, 0);
> > +}
> > +
> > +static void ssd2825_bridge_atomic_disable(struct drm_bridge *bridge,
> > + struct drm_bridge_state *old_bridge_state)
> > +{
> > + struct ssd2825_priv *priv = bridge_to_ssd2825(bridge);
> > + int ret;
> > +
> > + if (!priv->enabled)
> > + return;
> > +
> > + msleep(100);
> > +
> > + /* Exit DSI configuration register set */
> > + ssd2825_write_reg(priv, SSD2825_CONFIGURATION_REG,
> > + SSD2825_CONF_REG_ECD | SSD2825_CONF_REG_EOT);
> > + ssd2825_write_reg(priv, SSD2825_VC_CTRL_REG, 0);
> > +
> > + /* HW disable */
> > + gpiod_set_value_cansleep(priv->reset_gpio, 1);
> > + usleep_range(5000, 6000);
> > +
> > + ret = regulator_bulk_disable(ARRAY_SIZE(ssd2825_supplies),
> > + priv->supplies);
> > + if (ret < 0)
> > + dev_err(priv->dev, "error disabling regulators (%d)\n", ret);
> > +
> > + clk_disable_unprepare(priv->tx_clk);
> > +
> > + priv->enabled = false;
> > +}
> > +
> > +static int ssd2825_bridge_attach(struct drm_bridge *bridge,
> > + enum drm_bridge_attach_flags flags)
> > +{
> > + struct ssd2825_priv *priv = bridge_to_ssd2825(bridge);
> > +
> > + return drm_bridge_attach(bridge->encoder, priv->output.bridge, bridge,
> > + flags);
> > +}
> > +
> > +static enum drm_mode_status
> > +ssd2825_bridge_mode_valid(struct drm_bridge *bridge,
> > + const struct drm_display_info *info,
> > + const struct drm_display_mode *mode)
> > +{
> > + struct videomode vm;
> > +
> > + drm_display_mode_to_videomode(mode, &vm);
> > +
> > + /* maximum bit field size is 0xff apart active area which is 0xffff */
> > + if (vm.hsync_len > 0xff || vm.hback_porch > 0xff ||
> > + vm.hfront_porch > 0xff || vm.hactive > 0xffff)
>
> Some of these limitations are artificial or don't match the specs:
>
> Maximum pixels per display row 1366 2560
>
> etc.
>
> > + return MODE_H_ILLEGAL;
> > +
> > + if (vm.vsync_len > 0xff || vm.vback_porch > 0xff ||
> > + vm.vfront_porch > 0xff || vm.vactive > 0xffff)
> > + return MODE_V_ILLEGAL;
> > +
> > + return MODE_OK;
> > +}
> > +
> > +static bool ssd2825_mode_fixup(struct drm_bridge *bridge,
> > + const struct drm_display_mode *mode,
> > + struct drm_display_mode *adjusted_mode)
> > +{
> > + /* Default to positive sync */
> > +
> > + if (!(adjusted_mode->flags &
> > + (DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_NHSYNC)))
> > + adjusted_mode->flags |= DRM_MODE_FLAG_PHSYNC;
> > +
> > + if (!(adjusted_mode->flags &
> > + (DRM_MODE_FLAG_PVSYNC | DRM_MODE_FLAG_NVSYNC)))
> > + adjusted_mode->flags |= DRM_MODE_FLAG_PVSYNC;
>
> Why? I think that it is an error for the mode not to have one of those
> flags. Do you have an actual usecase?
>
> > +
> > + return true;
> > +}
> > +
> > +static const struct drm_bridge_funcs ssd2825_bridge_funcs = {
> > + .attach = ssd2825_bridge_attach,
> > + .mode_valid = ssd2825_bridge_mode_valid,
> > + .mode_fixup = ssd2825_mode_fixup,
> > +
> > + .atomic_pre_enable = ssd2825_bridge_atomic_pre_enable,
> > + .atomic_enable = ssd2825_bridge_atomic_enable,
> > + .atomic_disable = ssd2825_bridge_atomic_disable,
> > +
> > + .atomic_reset = drm_atomic_helper_bridge_reset,
> > + .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
> > + .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
> > +};
> > +
> > +static const struct drm_bridge_timings default_ssd2825_timings = {
> > + .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE
> > + | DRM_BUS_FLAG_SYNC_SAMPLE_NEGEDGE
> > + | DRM_BUS_FLAG_DE_HIGH,
> > +};
> > +
> > +static int ssd2825_probe(struct spi_device *spi)
> > +{
> > + struct ssd2825_priv *priv;
> > + struct device *dev = &spi->dev;
> > + struct device_node *np = dev->of_node;
> > + int ret;
> > +
> > + /* Driver supports only 8 bit 3 Wire mode */
> > + spi->bits_per_word = 9;
> > +
> > + ret = spi_setup(spi);
> > + if (ret)
> > + return ret;
> > +
> > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > + if (!priv)
> > + return -ENOMEM;
> > +
> > + spi_set_drvdata(spi, priv);
> > + priv->spi = spi;
> > +
> > + dev_set_drvdata(dev, priv);
> > + priv->dev = dev;
> > +
> > + mutex_init(&priv->mlock);
> > +
> > + priv->tx_clk = devm_clk_get_optional(dev, NULL);
> > + if (IS_ERR(priv->tx_clk))
> > + return dev_err_probe(dev, PTR_ERR(priv->tx_clk),
> > + "can't retrieve bridge tx_clk\n");
> > +
> > + priv->reset_gpio = devm_gpiod_get_optional(dev, "reset",
> > + GPIOD_OUT_HIGH);
> > + if (IS_ERR(priv->reset_gpio))
> > + return dev_err_probe(dev, PTR_ERR(priv->reset_gpio),
> > + "failed to get reset GPIO\n");
> > +
> > + ret = devm_regulator_bulk_get_const(dev, ARRAY_SIZE(ssd2825_supplies),
> > + ssd2825_supplies, &priv->supplies);
> > + if (ret)
> > + return dev_err_probe(dev, ret, "failed to get regulators\n");
> > +
> > + ret = device_property_read_u32(dev, "solomon,hs-zero-delay-ns", &priv->hzd);
> > + if (ret)
> > + /* If no hs-zero-delay is set by device tree, use the default 133 ns */
> > + priv->hzd = 133;
> > +
> > + ret = device_property_read_u32(dev, "solomon,hs-prep-delay-ns", &priv->hpd);
> > + if (ret)
> > + /* If no hs-prep-delay is set by device tree, use the default 40 ns */
> > + priv->hzd = 40;
> > +
> > + priv->dsi_host.dev = dev;
> > + priv->dsi_host.ops = &ssd2825_dsi_host_ops;
> > +
> > + priv->bridge.funcs = &ssd2825_bridge_funcs;
> > + priv->bridge.timings = &default_ssd2825_timings;
> > + priv->bridge.of_node = np;
> > +
> > + return mipi_dsi_host_register(&priv->dsi_host);
> > +}
> > +
> > +static void ssd2825_remove(struct spi_device *spi)
> > +{
> > + struct ssd2825_priv *priv = spi_get_drvdata(spi);
> > +
> > + mipi_dsi_host_unregister(&priv->dsi_host);
> > +}
> > +
> > +static const struct of_device_id ssd2825_of_match[] = {
> > + { .compatible = "solomon,ssd2825" },
> > + { /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, ssd2825_of_match);
> > +
> > +static struct spi_driver ssd2825_driver = {
> > + .driver = {
> > + .name = "ssd2825",
> > + .of_match_table = ssd2825_of_match,
> > + },
> > + .probe = ssd2825_probe,
> > + .remove = ssd2825_remove,
> > +};
> > +module_spi_driver(ssd2825_driver);
> > +
> > +MODULE_AUTHOR("Svyatoslav Ryhel <clamor95@...il.com>");
> > +MODULE_DESCRIPTION("Solomon SSD2825 RGB to MIPI-DSI bridge driver SPI");
> > +MODULE_LICENSE("GPL");
> > --
> > 2.43.0
> >
>
> --
> With best wishes
> Dmitry
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