Re: [PATCH v1 2/2] drm: bridge: Add support for Solomon SSD2825 RGB/DSI bridge

From: Svyatoslav Ryhel
Date: Thu Feb 13 2025 - 11:10:23 EST

чт, 13 лют. 2025 р. о 18:05 Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> пише:
>
> On Thu, Feb 13, 2025 at 03:56:05PM +0200, Svyatoslav Ryhel wrote:
> > SSD2825 is an innovative and cost-effective MIPI Bridge Chip solution
> > targeting high resolution smartphones. It can convert 24bit RGB
> > interface into 4-lane MIPI-DSI interface to drive extremely high
> > resolution display modules of up to 800 x 1366, while supporting AMOLED,
> > a-si LCD or LTPS advanced panel technologies for smartphone applications.
>
> Nit: I don't think that 800x1366 is considered high-res nowadays. Please
> consider rewriting the text in a non-marketing way.
>
> >
> > Signed-off-by: Svyatoslav Ryhel <clamor95@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/bridge/Kconfig | 13 +
> > drivers/gpu/drm/bridge/Makefile | 1 +
> > drivers/gpu/drm/bridge/ssd2825.c | 741 +++++++++++++++++++++++++++++++
> > 3 files changed, 755 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..74aec32d0f3b 100644
> > --- a/drivers/gpu/drm/bridge/Kconfig
> > +++ b/drivers/gpu/drm/bridge/Kconfig
> > @@ -306,6 +306,19 @@ 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 OF
> > + select DRM_MIPI_DSI
> > + select DRM_KMS_HELPER
> > + select DRM_PANEL
> > + 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..823f6dc023a5
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/ssd2825.c
> > @@ -0,0 +1,741 @@
> > +// 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/of.h>
> > +#include <linux/regulator/consumer.h>
> > +#include <linux/spi/spi.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 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 char * const ssd2825_supplies[] = {
> > + "dvdd", "avdd", "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[ARRAY_SIZE(ssd2825_supplies)];
> > +
> > + struct clk *tx_clk;
> > +
> > + int enabled;
> > +
> > + struct mipi_dsi_host dsi_host;
> > + struct drm_bridge bridge;
> > + struct ssd2825_dsi_output output;
> > +
> > + 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;
> > + }
>
> 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;
> > + }
> > +
> > + ret = ssd2825_read_reg(priv, SSD2825_CONFIGURATION_REG, &config);
> > + if (ret)
> > + return ret;
> > +
> > + 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:
> > + return 0;
> > + }
> > +
> > + ret = ssd2825_write_reg(priv, SSD2825_CONFIGURATION_REG, config);
> > + if (ret)
> > + return ret;
> > +
> > + ret = ssd2825_write_reg(priv, SSD2825_VC_CTRL_REG, 0x0000);
> > + if (ret)
> > + return ret;
> > +
> > + ret = ssd2825_write_dsi(priv, msg->tx_buf, msg->tx_len);
> > + if (ret)
> > + return ret;
>
> Do you need any kind of locking in case there are two simultaneous
> transfer operations?
>
> > +
> > + 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);
>
> 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);
>
> It looks like this should be a part of the .atomic_enable() callback.
>
> > + }
> > +
> > + 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;
> > + 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);
>
> 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_pre_enable(struct drm_bridge *bridge)
>
> Is there a reason not to use the .atomic versions?
>
> > +{
> > + 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(priv->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_enable(struct drm_bridge *bridge)
> > +{
> > + struct ssd2825_priv *priv = bridge_to_ssd2825(bridge);
> > + struct mipi_dsi_device *dsi_dev = priv->output.dev;
> > + unsigned long mode_flags = dsi_dev->mode_flags;
> > + const struct drm_display_mode *mode =
> > + &bridge->encoder->crtc->state->adjusted_mode;
>
> If you'd used atomic callbacks, you could have gone through the state to
> get corresponding data. Your main driver can be atomic, in which case
> you should not be using encoder->crtc and crtc->state.
>
> > + struct device *dev = priv->dev;
> > + u8 pixel_format;
> > +
> > + if (mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) {
> > + dev_warn_once(dev,
> > + "Non-continuous mode unimplemented, falling back to continuous\n");
> > + mode_flags &= ~MIPI_DSI_CLOCK_NON_CONTINUOUS;
> > + }
> > +
> > + if (mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
> > + dev_warn_once(dev,
> > + "Burst mode unimplemented, falling back to simple\n");
> > + mode_flags &= ~MIPI_DSI_MODE_VIDEO_BURST;
>
> This should be declined earlier, e.g. in the dsi_attach.
>
> > + }
> > +
> > + /* Perform SW reset */
> > + ssd2825_write_reg(priv, SSD2825_OPERATION_CTRL_REG, 0x0100);
> > +
> > + 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;
> > + }
> > +
> > + /* 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);
>
> Please check that the mode fits into corresponding bit fields in
> .mode_valid().
>
> > + ssd2825_write_reg(priv, SSD2825_RGB_INTERFACE_CTRL_REG_6,
> > + SSD2825_HSYNC_HIGH | SSD2825_VSYNC_HIGH |
> > + SSD2825_PCKL_HIGH | SSD2825_NON_BURST |
>
> These flags should come from drm_display_mode
>
> > + 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_disable(struct drm_bridge *bridge)
> > +{
> > + 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(priv->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)
> > +{
>
> No resulution / clock limitations?
>
> > + return MODE_OK;
> > +}
> > +
> > +static const struct drm_bridge_funcs ssd2825_bridge_funcs = {
> > + .attach = ssd2825_bridge_attach,
> > + .mode_valid = ssd2825_bridge_mode_valid,
> > + .pre_enable = ssd2825_bridge_pre_enable,
> > + .enable = ssd2825_bridge_enable,
> > + .disable = ssd2825_bridge_disable,
> > +};
> > +
> > +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 i, ret;
> > +
> > + /* Driver supports only this mode for now */
> > + 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;
> > +
> > + priv->tx_clk = devm_clk_get_optional(dev, "tx_clk");
> > + 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");
> > +
> > + for (i = 0; i < ARRAY_SIZE(priv->supplies); ++i)
> > + priv->supplies[i].supply = ssd2825_supplies[i];
>
> You can use devm_regulator_bulk_get_const() instead.
>
> > +
> > + ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(priv->supplies),
> > + priv->supplies);
> > + if (ret < 0)
> > + 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.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_DESCRIPTION("Solomon SSD2825 RGB to MIPI-DSI bridge driver SPI");
> > +MODULE_AUTHOR("Svyatoslav Ryhel <clamor95@xxxxxxxxx>");
> > +MODULE_LICENSE("GPL");
> > --
> > 2.43.0
> >
>
> --
> With best wishes
> Dmitry

Acknowledged, thank you.