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linux/drivers/gpu/drm/tiny/pixpaper.c
Nathan Chancellor 0265d0ebb4 drm/pixpaper: Fix return type of pixpaper_mode_valid() 
When building with -Wincompatible-function-pointer-types-strict, a
warning designed to catch kernel control flow integrity (kCFI) issues at
build time, there is an instance in the new tiny DRM pixpaper driver:

  drivers/gpu/drm/tiny/pixpaper.c:982:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_crtc *, const struct drm_display_mode *)' with an expression of type 'int (struct drm_crtc *, const struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict]
    982 |         .mode_valid = pixpaper_mode_valid,
        |                       ^~~~~~~~~~~~~~~~~~~

While 'int' and 'enum drm_mode_status' are ABI compatible, hence no
regular warning from -Wincompatible-function-pointer-types, the mismatch
will trigger a kCFI violation when pixpaper_mode_valid() is called
indirectly.

Update the return type of pixpaper_mode_valid() to be
'enum drm_mode_status' to clear up the warning and kCFI violation.

Fixes: c9e70639f5 ("drm: tiny: Add support for Mayqueen Pixpaper e-ink panel")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://lore.kernel.org/r/20250908-drm-pixpaper-fix-mode_valid-return-type-v1-1-705ceaf03757@kernel.org
2025-09-15 12:29:37 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* DRM driver for PIXPAPER e-ink panel
*
* Author: LiangCheng Wang <zaq14760@gmail.com>,
*/
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/spi/spi.h>
#include <drm/clients/drm_client_setup.h>
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_drv.h>
#include <drm/drm_fbdev_shmem.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_gem_atomic_helper.h>
#include <drm/drm_gem_shmem_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_probe_helper.h>
/*
* Note on Undocumented Commands/Registers:
*
* Several commands and register parameters defined in this header are not
* documented in the datasheet. Their values and usage have been derived
* through analysis of existing userspace example programs.
*
* These 'unknown' definitions are crucial for the proper initialization
* and stable operation of the panel. Modifying these values without
* thorough understanding may lead to display anomalies, panel damage,
* or unexpected behavior.
*/
/* Command definitions */
#define PIXPAPER_CMD_PANEL_SETTING 0x00 /* R00H: Panel settings */
#define PIXPAPER_CMD_POWER_SETTING 0x01 /* R01H: Power settings */
#define PIXPAPER_CMD_POWER_OFF 0x02 /* R02H: Power off */
#define PIXPAPER_CMD_POWER_OFF_SEQUENCE 0x03 /* R03H: Power off sequence */
#define PIXPAPER_CMD_POWER_ON 0x04 /* R04H: Power on */
#define PIXPAPER_CMD_BOOSTER_SOFT_START 0x06 /* R06H: Booster soft start */
#define PIXPAPER_CMD_DEEP_SLEEP 0x07 /* R07H: Deep sleep */
#define PIXPAPER_CMD_DATA_START_TRANSMISSION 0x10
/* R10H: Data transmission start */
#define PIXPAPER_CMD_DISPLAY_REFRESH 0x12 /* R12H: Display refresh */
#define PIXPAPER_CMD_PLL_CONTROL 0x30 /* R30H: PLL control */
#define PIXPAPER_CMD_TEMP_SENSOR_CALIB 0x41
/* R41H: Temperature sensor calibration */
#define PIXPAPER_CMD_UNKNOWN_4D 0x4D /* R4DH: Unknown command */
#define PIXPAPER_CMD_VCOM_INTERVAL 0x50 /* R50H: VCOM interval */
#define PIXPAPER_CMD_UNKNOWN_60 0x60 /* R60H: Unknown command */
#define PIXPAPER_CMD_RESOLUTION_SETTING 0x61 /* R61H: Resolution settings */
#define PIXPAPER_CMD_GATE_SOURCE_START 0x65 /* R65H: Gate/source start */
#define PIXPAPER_CMD_UNKNOWN_B4 0xB4 /* RB4H: Unknown command */
#define PIXPAPER_CMD_UNKNOWN_B5 0xB5 /* RB5H: Unknown command */
#define PIXPAPER_CMD_UNKNOWN_E0 0xE0 /* RE0H: Unknown command */
#define PIXPAPER_CMD_POWER_SAVING 0xE3 /* RE3H: Power saving */
#define PIXPAPER_CMD_UNKNOWN_E7 0xE7 /* RE7H: Unknown command */
#define PIXPAPER_CMD_UNKNOWN_E9 0xE9 /* RE9H: Unknown command */
/* R00H PSR - First Parameter */
#define PIXPAPER_PSR_RST_N BIT(0)
/* Bit 0: RST_N, 1=no effect (default), 0=reset with booster OFF */
#define PIXPAPER_PSR_SHD_N BIT(1)
/* Bit 1: SHD_N, 1=booster ON (default), 0=booster OFF */
#define PIXPAPER_PSR_SHL BIT(2)
/* Bit 2: SHL, 1=shift right (default), 0=shift left */
#define PIXPAPER_PSR_UD BIT(3)
/* Bit 3: UD, 1=scan up (default), 0=scan down */
#define PIXPAPER_PSR_PST_MODE BIT(5)
/* Bit 5: PST_MODE, 0=frame scanning (default), 1=external */
#define PIXPAPER_PSR_RES_MASK (3 << 6)
/* Bits 7-6: RES[1:0], resolution setting */
#define PIXPAPER_PSR_RES_176x296 (0x0 << 6) /* 00: 176x296 */
#define PIXPAPER_PSR_RES_128x296 (0x1 << 6) /* 01: 128x296 */
#define PIXPAPER_PSR_RES_128x250 (0x2 << 6) /* 10: 128x250 */
#define PIXPAPER_PSR_RES_112x204 (0x3 << 6) /* 11: 112x204 */
#define PIXPAPER_PSR_CONFIG \
(PIXPAPER_PSR_RST_N | PIXPAPER_PSR_SHD_N | PIXPAPER_PSR_SHL | \
PIXPAPER_PSR_UD)
/* 0x0F: Default settings, resolution set by R61H */
/* R00H PSR - Second Parameter */
#define PIXPAPER_PSR2_VC_LUTZ \
(1 << 0) /* Bit 0: VC_LUTZ, 1=VCOM float after refresh (default), 0=no effect */
#define PIXPAPER_PSR2_NORG \
(1 << 1) /* Bit 1: NORG, 1=VCOM to GND before power off, 0=no effect (default) */
#define PIXPAPER_PSR2_TIEG \
(1 << 2) /* Bit 2: TIEG, 1=VGN to GND on power off, 0=no effect (default) */
#define PIXPAPER_PSR2_TS_AUTO \
(1 << 3) /* Bit 3: TS_AUTO, 1=sensor on RST_N low to high (default), 0=on booster */
#define PIXPAPER_PSR2_VCMZ \
(1 << 4) /* Bit 4: VCMZ, 1=VCOM always floating, 0=no effect (default) */
#define PIXPAPER_PSR2_FOPT \
(1 << 5) /* Bit 5: FOPT, 0=scan 1 frame (default), 1=no scan, HiZ */
#define PIXPAPER_PSR_CONFIG2 \
(PIXPAPER_PSR2_VC_LUTZ | \
PIXPAPER_PSR2_TS_AUTO) /* 0x09: Default VCOM and temp sensor settings */
/* R01H PWR - Power Setting Register */
/* First Parameter */
#define PIXPAPER_PWR_VDG_EN \
(1 << 0) /* Bit 0: VDG_EN, 1=internal DCDC for VGP/VGN (default), 0=external */
#define PIXPAPER_PWR_VDS_EN \
(1 << 1) /* Bit 1: VDS_EN, 1=internal regulator for VSP/VSN (default), 0=external */
#define PIXPAPER_PWR_VSC_EN \
(1 << 2) /* Bit 2: VSC_EN, 1=internal regulator for VSPL (default), 0=external */
#define PIXPAPER_PWR_V_MODE \
(1 << 3) /* Bit 3: V_MODE, 0=Mode0 (default), 1=Mode1 */
#define PIXPAPER_PWR_CONFIG1 \
(PIXPAPER_PWR_VDG_EN | PIXPAPER_PWR_VDS_EN | \
PIXPAPER_PWR_VSC_EN) /* 0x07: Internal power for VGP/VGN, VSP/VSN, VSPL */
/* Second Parameter */
#define PIXPAPER_PWR_VGPN_MASK \
(3 << 0) /* Bits 1-0: VGPN, VGP/VGN voltage levels */
#define PIXPAPER_PWR_VGPN_20V (0x0 << 0) /* 00: VGP=20V, VGN=-20V (default) */
#define PIXPAPER_PWR_VGPN_17V (0x1 << 0) /* 01: VGP=17V, VGN=-17V */
#define PIXPAPER_PWR_VGPN_15V (0x2 << 0) /* 10: VGP=15V, VGN=-15V */
#define PIXPAPER_PWR_VGPN_10V (0x3 << 0) /* 11: VGP=10V, VGN=-10V */
#define PIXPAPER_PWR_CONFIG2 PIXPAPER_PWR_VGPN_20V /* 0x00: VGP=20V, VGN=-20V */
/* Third, Fourth, Sixth Parameters (VSP_1, VSPL_0, VSPL_1) */
#define PIXPAPER_PWR_VSP_8_2V 0x22 /* VSP_1/VSPL_1: 8.2V (34 decimal) */
#define PIXPAPER_PWR_VSPL_15V 0x78 /* VSPL_0: 15V (120 decimal) */
/* Fifth Parameter (VSN_1) */
#define PIXPAPER_PWR_VSN_4V 0x0A /* VSN_1: -4V (10 decimal) */
/* R03H PFS - Power Off Sequence Setting Register */
/* First Parameter */
#define PIXPAPER_PFS_T_VDS_OFF_MASK \
(3 << 0) /* Bits 1-0: T_VDS_OFF, VSP/VSN power-off sequence */
#define PIXPAPER_PFS_T_VDS_OFF_20MS (0x0 << 0) /* 00: 20 ms (default) */
#define PIXPAPER_PFS_T_VDS_OFF_40MS (0x1 << 0) /* 01: 40 ms */
#define PIXPAPER_PFS_T_VDS_OFF_60MS (0x2 << 0) /* 10: 60 ms */
#define PIXPAPER_PFS_T_VDS_OFF_80MS (0x3 << 0) /* 11: 80 ms */
#define PIXPAPER_PFS_T_VDPG_OFF_MASK \
(3 << 4) /* Bits 5-4: T_VDPG_OFF, VGP/VGN power-off sequence */
#define PIXPAPER_PFS_T_VDPG_OFF_20MS (0x0 << 4) /* 00: 20 ms (default) */
#define PIXPAPER_PFS_T_VDPG_OFF_40MS (0x1 << 4) /* 01: 40 ms */
#define PIXPAPER_PFS_T_VDPG_OFF_60MS (0x2 << 4) /* 10: 60 ms */
#define PIXPAPER_PFS_T_VDPG_OFF_80MS (0x3 << 4) /* 11: 80 ms */
#define PIXPAPER_PFS_CONFIG1 \
(PIXPAPER_PFS_T_VDS_OFF_20MS | \
PIXPAPER_PFS_T_VDPG_OFF_20MS) /* 0x10: Default 20 ms for VSP/VSN and VGP/VGN */
/* Second Parameter */
#define PIXPAPER_PFS_VGP_EXT_MASK \
(0xF << 0) /* Bits 3-0: VGP_EXT, VGP extension time */
#define PIXPAPER_PFS_VGP_EXT_0MS (0x0 << 0) /* 0000: 0 ms */
#define PIXPAPER_PFS_VGP_EXT_500MS (0x1 << 0) /* 0001: 500 ms */
#define PIXPAPER_PFS_VGP_EXT_1000MS (0x2 << 0) /* 0010: 1000 ms */
#define PIXPAPER_PFS_VGP_EXT_1500MS (0x3 << 0) /* 0011: 1500 ms */
#define PIXPAPER_PFS_VGP_EXT_2000MS (0x4 << 0) /* 0100: 2000 ms (default) */
#define PIXPAPER_PFS_VGP_EXT_2500MS (0x5 << 0) /* 0101: 2500 ms */
#define PIXPAPER_PFS_VGP_EXT_3000MS (0x6 << 0) /* 0110: 3000 ms */
#define PIXPAPER_PFS_VGP_EXT_3500MS (0x7 << 0) /* 0111: 3500 ms */
#define PIXPAPER_PFS_VGP_EXT_4000MS (0x8 << 0) /* 1000: 4000 ms */
#define PIXPAPER_PFS_VGP_EXT_4500MS (0x9 << 0) /* 1001: 4500 ms */
#define PIXPAPER_PFS_VGP_EXT_5000MS (0xA << 0) /* 1010: 5000 ms */
#define PIXPAPER_PFS_VGP_EXT_5500MS (0xB << 0) /* 1011: 5500 ms */
#define PIXPAPER_PFS_VGP_EXT_6000MS (0xC << 0) /* 1100: 6000 ms */
#define PIXPAPER_PFS_VGP_EXT_6500MS (0xD << 0) /* 1101: 6500 ms */
#define PIXPAPER_PFS_VGP_LEN_MASK \
(0xF << 4) /* Bits 7-4: VGP_LEN, VGP at 10V during power-off */
#define PIXPAPER_PFS_VGP_LEN_0MS (0x0 << 4) /* 0000: 0 ms */
#define PIXPAPER_PFS_VGP_LEN_500MS (0x1 << 4) /* 0001: 500 ms */
#define PIXPAPER_PFS_VGP_LEN_1000MS (0x2 << 4) /* 0010: 1000 ms */
#define PIXPAPER_PFS_VGP_LEN_1500MS (0x3 << 4) /* 0011: 1500 ms */
#define PIXPAPER_PFS_VGP_LEN_2000MS (0x4 << 4) /* 0100: 2000 ms */
#define PIXPAPER_PFS_VGP_LEN_2500MS (0x5 << 4) /* 0101: 2500 ms (default) */
#define PIXPAPER_PFS_VGP_LEN_3000MS (0x6 << 4) /* 0110: 3000 ms */
#define PIXPAPER_PFS_VGP_LEN_3500MS (0x7 << 4) /* 0111: 3500 ms */
#define PIXPAPER_PFS_VGP_LEN_4000MS (0x8 << 4) /* 1000: 4000 ms */
#define PIXPAPER_PFS_VGP_LEN_4500MS (0x9 << 4) /* 1001: 4500 ms */
#define PIXPAPER_PFS_VGP_LEN_5000MS (0xA << 4) /* 1010: 5000 ms */
#define PIXPAPER_PFS_VGP_LEN_5500MS (0xB << 4) /* 1011: 5500 ms */
#define PIXPAPER_PFS_VGP_LEN_6000MS (0xC << 4) /* 1100: 6000 ms */
#define PIXPAPER_PFS_VGP_LEN_6500MS (0xD << 4) /* 1101: 6500 ms */
#define PIXPAPER_PFS_CONFIG2 \
(PIXPAPER_PFS_VGP_EXT_1000MS | \
PIXPAPER_PFS_VGP_LEN_2500MS) /* 0x54: VGP extension 1000 ms, VGP at 10V for 2500 ms */
/* Third Parameter */
#define PIXPAPER_PFS_XON_LEN_MASK \
(0xF << 0) /* Bits 3-0: XON_LEN, XON enable time */
#define PIXPAPER_PFS_XON_LEN_0MS (0x0 << 0) /* 0000: 0 ms */
#define PIXPAPER_PFS_XON_LEN_500MS (0x1 << 0) /* 0001: 500 ms */
#define PIXPAPER_PFS_XON_LEN_1000MS (0x2 << 0) /* 0010: 1000 ms */
#define PIXPAPER_PFS_XON_LEN_1500MS (0x3 << 0) /* 0011: 1500 ms */
#define PIXPAPER_PFS_XON_LEN_2000MS (0x4 << 0) /* 0100: 2000 ms (default) */
#define PIXPAPER_PFS_XON_LEN_2500MS (0x5 << 0) /* 0101: 2500 ms */
#define PIXPAPER_PFS_XON_LEN_3000MS (0x6 << 0) /* 0110: 3000 ms */
#define PIXPAPER_PFS_XON_LEN_3500MS (0x7 << 0) /* 0111: 3500 ms */
#define PIXPAPER_PFS_XON_LEN_4000MS (0x8 << 0) /* 1000: 4000 ms */
#define PIXPAPER_PFS_XON_LEN_4500MS (0x9 << 0) /* 1001: 4500 ms */
#define PIXPAPER_PFS_XON_LEN_5000MS (0xA << 0) /* 1010: 5000 ms */
#define PIXPAPER_PFS_XON_LEN_5500MS (0xB << 0) /* 1011: 5500 ms */
#define PIXPAPER_PFS_XON_LEN_6000MS (0xC << 0) /* 1100: 6000 ms */
#define PIXPAPER_PFS_XON_DLY_MASK \
(0xF << 4) /* Bits 7-4: XON_DLY, XON delay time */
#define PIXPAPER_PFS_XON_DLY_0MS (0x0 << 4) /* 0000: 0 ms */
#define PIXPAPER_PFS_XON_DLY_500MS (0x1 << 4) /* 0001: 500 ms */
#define PIXPAPER_PFS_XON_DLY_1000MS (0x2 << 4) /* 0010: 1000 ms */
#define PIXPAPER_PFS_XON_DLY_1500MS (0x3 << 4) /* 0011: 1500 ms */
#define PIXPAPER_PFS_XON_DLY_2000MS (0x4 << 4) /* 0100: 2000 ms (default) */
#define PIXPAPER_PFS_XON_DLY_2500MS (0x5 << 4) /* 0101: 2500 ms */
#define PIXPAPER_PFS_XON_DLY_3000MS (0x6 << 4) /* 0110: 3000 ms */
#define PIXPAPER_PFS_XON_DLY_3500MS (0x7 << 4) /* 0111: 3500 ms */
#define PIXPAPER_PFS_XON_DLY_4000MS (0x8 << 4) /* 1000: 4000 ms */
#define PIXPAPER_PFS_XON_DLY_4500MS (0x9 << 4) /* 1001: 4500 ms */
#define PIXPAPER_PFS_XON_DLY_5000MS (0xA << 4) /* 1010: 5000 ms */
#define PIXPAPER_PFS_XON_DLY_5500MS (0xB << 4) /* 1011: 5500 ms */
#define PIXPAPER_PFS_XON_DLY_6000MS (0xC << 4) /* 1100: 6000 ms */
#define PIXPAPER_PFS_CONFIG3 \
(PIXPAPER_PFS_XON_LEN_2000MS | \
PIXPAPER_PFS_XON_DLY_2000MS) /* 0x44: XON enable and delay at 2000 ms */
/* R06H BTST - Booster Soft Start Command */
/* First Parameter */
#define PIXPAPER_BTST_PHA_SFT_MASK \
(3 << 0) /* Bits 1-0: PHA_SFT, soft start period for phase A */
#define PIXPAPER_BTST_PHA_SFT_10MS (0x0 << 0) /* 00: 10 ms (default) */
#define PIXPAPER_BTST_PHA_SFT_20MS (0x1 << 0) /* 01: 20 ms */
#define PIXPAPER_BTST_PHA_SFT_30MS (0x2 << 0) /* 10: 30 ms */
#define PIXPAPER_BTST_PHA_SFT_40MS (0x3 << 0) /* 11: 40 ms */
#define PIXPAPER_BTST_PHB_SFT_MASK \
(3 << 2) /* Bits 3-2: PHB_SFT, soft start period for phase B */
#define PIXPAPER_BTST_PHB_SFT_10MS (0x0 << 2) /* 00: 10 ms (default) */
#define PIXPAPER_BTST_PHB_SFT_20MS (0x1 << 2) /* 01: 20 ms */
#define PIXPAPER_BTST_PHB_SFT_30MS (0x2 << 2) /* 10: 30 ms */
#define PIXPAPER_BTST_PHB_SFT_40MS (0x3 << 2) /* 11: 40 ms */
#define PIXPAPER_BTST_CONFIG1 \
(PIXPAPER_BTST_PHA_SFT_40MS | \
PIXPAPER_BTST_PHB_SFT_40MS) /* 0x0F: 40 ms for phase A and B */
/* Second to Seventh Parameters (Driving Strength or Minimum OFF Time) */
#define PIXPAPER_BTST_CONFIG2 0x0A /* Strength11 */
#define PIXPAPER_BTST_CONFIG3 0x2F /* Period48 */
#define PIXPAPER_BTST_CONFIG4 0x25 /* Strength38 */
#define PIXPAPER_BTST_CONFIG5 0x22 /* Period35 */
#define PIXPAPER_BTST_CONFIG6 0x2E /* Strength47 */
#define PIXPAPER_BTST_CONFIG7 0x21 /* Period34 */
/* R12H: DRF (Display Refresh) */
#define PIXPAPER_DRF_VCOM_AC 0x00 /* AC VCOM: VCOM follows LUTC (default) */
#define PIXPAPER_DRF_VCOM_DC 0x01 /* DC VCOM: VCOM fixed to VCOMDC */
/* R30H PLL - PLL Control Register */
/* First Parameter */
#define PIXPAPER_PLL_FR_MASK (0x7 << 0) /* Bits 2-0: FR, frame rate */
#define PIXPAPER_PLL_FR_12_5HZ (0x0 << 0) /* 000: 12.5 Hz */
#define PIXPAPER_PLL_FR_25HZ (0x1 << 0) /* 001: 25 Hz */
#define PIXPAPER_PLL_FR_50HZ (0x2 << 0) /* 010: 50 Hz (default) */
#define PIXPAPER_PLL_FR_65HZ (0x3 << 0) /* 011: 65 Hz */
#define PIXPAPER_PLL_FR_75HZ (0x4 << 0) /* 100: 75 Hz */
#define PIXPAPER_PLL_FR_85HZ (0x5 << 0) /* 101: 85 Hz */
#define PIXPAPER_PLL_FR_100HZ (0x6 << 0) /* 110: 100 Hz */
#define PIXPAPER_PLL_FR_120HZ (0x7 << 0) /* 111: 120 Hz */
#define PIXPAPER_PLL_DFR \
(1 << 3) /* Bit 3: Dynamic frame rate, 0=disabled (default), 1=enabled */
#define PIXPAPER_PLL_CONFIG \
(PIXPAPER_PLL_FR_50HZ) /* 0x02: 50 Hz, dynamic frame rate disabled */
/* R41H TSE - Temperature Sensor Calibration Register */
/* First Parameter */
#define PIXPAPER_TSE_TO_MASK \
(0xF << 0) /* Bits 3-0: TO[3:0], temperature offset */
#define PIXPAPER_TSE_TO_POS_0C (0x0 << 0) /* 0000: +0°C (default) */
#define PIXPAPER_TSE_TO_POS_0_5C (0x1 << 0) /* 0001: +0.5°C */
#define PIXPAPER_TSE_TO_POS_1C (0x2 << 0) /* 0010: +1°C */
#define PIXPAPER_TSE_TO_POS_1_5C (0x3 << 0) /* 0011: +1.5°C */
#define PIXPAPER_TSE_TO_POS_2C (0x4 << 0) /* 0100: +2°C */
#define PIXPAPER_TSE_TO_POS_2_5C (0x5 << 0) /* 0101: +2.5°C */
#define PIXPAPER_TSE_TO_POS_3C (0x6 << 0) /* 0110: +3°C */
#define PIXPAPER_TSE_TO_POS_3_5C (0x7 << 0) /* 0111: +3.5°C */
#define PIXPAPER_TSE_TO_NEG_4C (0x8 << 0) /* 1000: -4°C */
#define PIXPAPER_TSE_TO_NEG_3_5C (0x9 << 0) /* 1001: -3.5°C */
#define PIXPAPER_TSE_TO_NEG_3C (0xA << 0) /* 1010: -3°C */
#define PIXPAPER_TSE_TO_NEG_2_5C (0xB << 0) /* 1011: -2.5°C */
#define PIXPAPER_TSE_TO_NEG_2C (0xC << 0) /* 1100: -2°C */
#define PIXPAPER_TSE_TO_NEG_1_5C (0xD << 0) /* 1101: -1.5°C */
#define PIXPAPER_TSE_TO_NEG_1C (0xE << 0) /* 1110: -1°C */
#define PIXPAPER_TSE_TO_NEG_0_5C (0xF << 0) /* 1111: -0.5°C */
#define PIXPAPER_TSE_TO_FINE_MASK \
(0x3 << 4) /* Bits 5-4: TO[5:4], fine adjustment for positive offsets */
#define PIXPAPER_TSE_TO_FINE_0C (0x0 << 4) /* 00: +0.0°C (default) */
#define PIXPAPER_TSE_TO_FINE_0_25C (0x1 << 4) /* 01: +0.25°C */
#define PIXPAPER_TSE_ENABLE \
(0 << 7) /* Bit 7: TSE, 0=internal sensor enabled (default), 1=disabled (external) */
#define PIXPAPER_TSE_DISABLE \
(1 << 7) /* Bit 7: TSE, 1=internal sensor disabled, use external */
#define PIXPAPER_TSE_CONFIG \
(PIXPAPER_TSE_TO_POS_0C | PIXPAPER_TSE_TO_FINE_0C | \
PIXPAPER_TSE_ENABLE) /* 0x00: Internal sensor enabled, +0°C offset */
/* R4DH */
#define PIXPAPER_UNKNOWN_4D_CONFIG \
0x78 /* This value is essential for initialization, derived from userspace examples. */
/* R50H CDI - VCOM and DATA Interval Setting Register */
/* First Parameter */
#define PIXPAPER_CDI_INTERVAL_MASK \
(0xF << 0) /* Bits 3-0: CDI[3:0], VCOM and data interval (hsync) */
#define PIXPAPER_CDI_17_HSYNC (0x0 << 0) /* 0000: 17 hsync */
#define PIXPAPER_CDI_16_HSYNC (0x1 << 0) /* 0001: 16 hsync */
#define PIXPAPER_CDI_15_HSYNC (0x2 << 0) /* 0010: 15 hsync */
#define PIXPAPER_CDI_14_HSYNC (0x3 << 0) /* 0011: 14 hsync */
#define PIXPAPER_CDI_13_HSYNC (0x4 << 0) /* 0100: 13 hsync */
#define PIXPAPER_CDI_12_HSYNC (0x5 << 0) /* 0101: 12 hsync */
#define PIXPAPER_CDI_11_HSYNC (0x6 << 0) /* 0110: 11 hsync */
#define PIXPAPER_CDI_10_HSYNC (0x7 << 0) /* 0111: 10 hsync (default) */
#define PIXPAPER_CDI_9_HSYNC (0x8 << 0) /* 1000: 9 hsync */
#define PIXPAPER_CDI_8_HSYNC (0x9 << 0) /* 1001: 8 hsync */
#define PIXPAPER_CDI_7_HSYNC (0xA << 0) /* 1010: 7 hsync */
#define PIXPAPER_CDI_6_HSYNC (0xB << 0) /* 1011: 6 hsync */
#define PIXPAPER_CDI_5_HSYNC (0xC << 0) /* 1100: 5 hsync */
#define PIXPAPER_CDI_4_HSYNC (0xD << 0) /* 1101: 4 hsync */
#define PIXPAPER_CDI_3_HSYNC (0xE << 0) /* 1110: 3 hsync */
#define PIXPAPER_CDI_2_HSYNC (0xF << 0) /* 1111: 2 hsync */
#define PIXPAPER_CDI_DDX \
(1 << 4) /* Bit 4: DDX, 0=grayscale mapping 0, 1=grayscale mapping 1 (default) */
#define PIXPAPER_CDI_VBD_MASK \
(0x7 << 5) /* Bits 7-5: VBD[2:0], border data selection */
#define PIXPAPER_CDI_VBD_FLOAT (0x0 << 5) /* 000: Floating (DDX=0 or 1) */
#define PIXPAPER_CDI_VBD_GRAY3_DDX0 \
(0x1 << 5) /* 001: Gray3 (border_buf=011) when DDX=0 */
#define PIXPAPER_CDI_VBD_GRAY2_DDX0 \
(0x2 << 5) /* 010: Gray2 (border_buf=010) when DDX=0 */
#define PIXPAPER_CDI_VBD_GRAY1_DDX0 \
(0x3 << 5) /* 011: Gray1 (border_buf=001) when DDX=0 */
#define PIXPAPER_CDI_VBD_GRAY0_DDX0 \
(0x4 << 5) /* 100: Gray0 (border_buf=000) when DDX=0 */
#define PIXPAPER_CDI_VBD_GRAY0_DDX1 \
(0x0 << 5) /* 000: Gray0 (border_buf=000) when DDX=1 */
#define PIXPAPER_CDI_VBD_GRAY1_DDX1 \
(0x1 << 5) /* 001: Gray1 (border_buf=001) when DDX=1 */
#define PIXPAPER_CDI_VBD_GRAY2_DDX1 \
(0x2 << 5) /* 010: Gray2 (border_buf=010) when DDX=1 */
#define PIXPAPER_CDI_VBD_GRAY3_DDX1 \
(0x3 << 5) /* 011: Gray3 (border_buf=011) when DDX=1 */
#define PIXPAPER_CDI_VBD_FLOAT_DDX1 (0x4 << 5) /* 100: Floating when DDX=1 */
#define PIXPAPER_CDI_CONFIG \
(PIXPAPER_CDI_10_HSYNC | PIXPAPER_CDI_DDX | \
PIXPAPER_CDI_VBD_GRAY1_DDX1) /* 0x37: 10 hsync, DDX=1, border Gray1 */
/* R60H */
#define PIXPAPER_UNKNOWN_60_CONFIG1 \
0x02 /* This value is essential for initialization, derived from userspace examples. */
#define PIXPAPER_UNKNOWN_60_CONFIG2 \
0x02 /* This value is essential for initialization, derived from userspace examples. */
/* R61H TRES - Resolution Setting Register */
#define PIXPAPER_TRES_HRES_H \
((PIXPAPER_PANEL_BUFFER_WIDTH >> 8) & \
0xFF) /* HRES[9:8]: High byte of horizontal resolution (128) */
#define PIXPAPER_TRES_HRES_L \
(PIXPAPER_PANEL_BUFFER_WIDTH & \
0xFF) /* HRES[7:0]: Low byte of horizontal resolution (128 = 0x80) */
#define PIXPAPER_TRES_VRES_H \
((PIXPAPER_HEIGHT >> 8) & \
0xFF) /* VRES[9:8]: High byte of vertical resolution (250) */
#define PIXPAPER_TRES_VRES_L \
(PIXPAPER_HEIGHT & \
0xFF) /* VRES[7:0]: Low byte of vertical resolution (250 = 0xFA) */
/* R65H GSST - Gate/Source Start Setting Register */
#define PIXPAPER_GSST_S_START 0x00 /* S_Start[7:0]: First source line (S0) */
#define PIXPAPER_GSST_RESERVED 0x00 /* Reserved byte */
#define PIXPAPER_GSST_G_START_H \
0x00 /* G_Start[8]: High bit of first gate line (G0) */
#define PIXPAPER_GSST_G_START_L \
0x00 /* G_Start[7:0]: Low byte of first gate line (G0) */
/* RB4H */
#define PIXPAPER_UNKNOWN_B4_CONFIG \
0xD0 /* This value is essential for initialization, derived from userspace examples. */
/* RB5H */
#define PIXPAPER_UNKNOWN_B5_CONFIG \
0x03 /* This value is essential for initialization, derived from userspace examples. */
/* RE0H */
#define PIXPAPER_UNKNOWN_E0_CONFIG \
0x00 /* This value is essential for initialization, derived from userspace examples. */
/* RE3H PWS - Power Saving Register */
/* First Parameter */
#define PIXPAPER_PWS_VCOM_W_MASK \
(0xF \
<< 4) /* Bits 7-4: VCOM_W[3:0], VCOM power-saving width (line periods) */
#define PIXPAPER_PWS_VCOM_W_0 (0x0 << 4) /* 0000: 0 line periods */
#define PIXPAPER_PWS_VCOM_W_1 (0x1 << 4) /* 0001: 1 line period */
#define PIXPAPER_PWS_VCOM_W_2 (0x2 << 4) /* 0010: 2 line periods */
#define PIXPAPER_PWS_VCOM_W_3 (0x3 << 4) /* 0011: 3 line periods */
#define PIXPAPER_PWS_VCOM_W_4 (0x4 << 4) /* 0100: 4 line periods */
#define PIXPAPER_PWS_VCOM_W_5 (0x5 << 4) /* 0101: 5 line periods */
#define PIXPAPER_PWS_VCOM_W_6 (0x6 << 4) /* 0110: 6 line periods */
#define PIXPAPER_PWS_VCOM_W_7 (0x7 << 4) /* 0111: 7 line periods */
#define PIXPAPER_PWS_VCOM_W_8 (0x8 << 4) /* 1000: 8 line periods */
#define PIXPAPER_PWS_VCOM_W_9 (0x9 << 4) /* 1001: 9 line periods */
#define PIXPAPER_PWS_VCOM_W_10 (0xA << 4) /* 1010: 10 line periods */
#define PIXPAPER_PWS_VCOM_W_11 (0xB << 4) /* 1011: 11 line periods */
#define PIXPAPER_PWS_VCOM_W_12 (0xC << 4) /* 1100: 12 line periods */
#define PIXPAPER_PWS_VCOM_W_13 (0xD << 4) /* 1101: 13 line periods */
#define PIXPAPER_PWS_VCOM_W_14 (0xE << 4) /* 1110: 14 line periods */
#define PIXPAPER_PWS_VCOM_W_15 (0xF << 4) /* 1111: 15 line periods */
#define PIXPAPER_PWS_SD_W_MASK \
(0xF << 0) /* Bits 3-0: SD_W[3:0], source power-saving width (660 ns units) */
#define PIXPAPER_PWS_SD_W_0 (0x0 << 0) /* 0000: 0 ns */
#define PIXPAPER_PWS_SD_W_1 (0x1 << 0) /* 0001: 660 ns */
#define PIXPAPER_PWS_SD_W_2 (0x2 << 0) /* 0010: 1320 ns */
#define PIXPAPER_PWS_SD_W_3 (0x3 << 0) /* 0011: 1980 ns */
#define PIXPAPER_PWS_SD_W_4 (0x4 << 0) /* 0100: 2640 ns */
#define PIXPAPER_PWS_SD_W_5 (0x5 << 0) /* 0101: 3300 ns */
#define PIXPAPER_PWS_SD_W_6 (0x6 << 0) /* 0110: 3960 ns */
#define PIXPAPER_PWS_SD_W_7 (0x7 << 0) /* 0111: 4620 ns */
#define PIXPAPER_PWS_SD_W_8 (0x8 << 0) /* 1000: 5280 ns */
#define PIXPAPER_PWS_SD_W_9 (0x9 << 0) /* 1001: 5940 ns */
#define PIXPAPER_PWS_SD_W_10 (0xA << 0) /* 1010: 6600 ns */
#define PIXPAPER_PWS_SD_W_11 (0xB << 0) /* 1011: 7260 ns */
#define PIXPAPER_PWS_SD_W_12 (0xC << 0) /* 1100: 7920 ns */
#define PIXPAPER_PWS_SD_W_13 (0xD << 0) /* 1101: 8580 ns */
#define PIXPAPER_PWS_SD_W_14 (0xE << 0) /* 1110: 9240 ns */
#define PIXPAPER_PWS_SD_W_15 (0xF << 0) /* 1111: 9900 ns */
#define PIXPAPER_PWS_CONFIG \
(PIXPAPER_PWS_VCOM_W_2 | \
PIXPAPER_PWS_SD_W_2) /* 0x22: VCOM 2 line periods (160 µs), source 1320 ns */
/* RE7H */
#define PIXPAPER_UNKNOWN_E7_CONFIG \
0x1C /* This value is essential for initialization, derived from userspace examples. */
/* RE9H */
#define PIXPAPER_UNKNOWN_E9_CONFIG \
0x01 /* This value is essential for initialization, derived from userspace examples. */
MODULE_IMPORT_NS("DMA_BUF");
/*
* The panel has a visible resolution of 122x250.
* However, the controller requires the horizontal resolution to be aligned to 128 pixels.
* No porch or sync timing values are provided in the datasheet, so we define minimal
* placeholder values to satisfy the DRM framework.
*/
/* Panel visible resolution */
#define PIXPAPER_WIDTH 122
#define PIXPAPER_HEIGHT 250
/* Controller requires 128 horizontal pixels total (for memory alignment) */
#define PIXPAPER_HTOTAL 128
#define PIXPAPER_HFP 2
#define PIXPAPER_HSYNC 2
#define PIXPAPER_HBP (PIXPAPER_HTOTAL - PIXPAPER_WIDTH - PIXPAPER_HFP - PIXPAPER_HSYNC)
/*
* According to the datasheet, the total vertical blanking must be 55 lines,
* regardless of how the vertical back porch is set.
* Here we allocate VFP=2, VSYNC=2, and VBP=51 to sum up to 55 lines.
* Total vertical lines = 250 (visible) + 55 (blanking) = 305.
*/
#define PIXPAPER_VTOTAL (250 + 55)
#define PIXPAPER_VFP 2
#define PIXPAPER_VSYNC 2
#define PIXPAPER_VBP (55 - PIXPAPER_VFP - PIXPAPER_VSYNC)
/*
* Pixel clock calculation:
* pixel_clock = htotal * vtotal * refresh_rate
* = 128 * 305 * 50
* = 1,952,000 Hz = 1952 kHz
*/
#define PIXPAPER_PIXEL_CLOCK 1952
#define PIXPAPER_WIDTH_MM 24 /* approximate from 23.7046mm */
#define PIXPAPER_HEIGHT_MM 49 /* approximate from 48.55mm */
#define PIXPAPER_SPI_BITS_PER_WORD 8
#define PIXPAPER_SPI_SPEED_DEFAULT 1000000
#define PIXPAPER_PANEL_BUFFER_WIDTH 128
#define PIXPAPER_PANEL_BUFFER_TWO_BYTES_PER_ROW (PIXPAPER_PANEL_BUFFER_WIDTH / 4)
#define PIXPAPER_COLOR_THRESHOLD_LOW_CHANNEL 60
#define PIXPAPER_COLOR_THRESHOLD_HIGH_CHANNEL 200
#define PIXPAPER_COLOR_THRESHOLD_YELLOW_MIN_GREEN 180
struct pixpaper_error_ctx {
int errno_code;
};
struct pixpaper_panel {
struct drm_device drm;
struct drm_plane plane;
struct drm_crtc crtc;
struct drm_encoder encoder;
struct drm_connector connector;
struct spi_device *spi;
struct gpio_desc *reset;
struct gpio_desc *busy;
struct gpio_desc *dc;
};
static inline struct pixpaper_panel *to_pixpaper_panel(struct drm_device *drm)
{
return container_of(drm, struct pixpaper_panel, drm);
}
static void pixpaper_wait_for_panel(struct pixpaper_panel *panel)
{
unsigned int timeout_ms = 10000;
unsigned long timeout_jiffies = jiffies + msecs_to_jiffies(timeout_ms);
usleep_range(1000, 1500);
while (gpiod_get_value_cansleep(panel->busy) != 1) {
if (time_after(jiffies, timeout_jiffies)) {
drm_warn(&panel->drm, "Busy wait timed out\n");
return;
}
usleep_range(100, 200);
}
}
static void pixpaper_spi_sync(struct spi_device *spi, struct spi_message *msg,
struct pixpaper_error_ctx *err)
{
if (err->errno_code)
return;
int ret = spi_sync(spi, msg);
if (ret < 0)
err->errno_code = ret;
}
static void pixpaper_send_cmd(struct pixpaper_panel *panel, u8 cmd,
struct pixpaper_error_ctx *err)
{
if (err->errno_code)
return;
struct spi_transfer xfer = {
.tx_buf = &cmd,
.len = 1,
};
struct spi_message msg;
spi_message_init(&msg);
spi_message_add_tail(&xfer, &msg);
gpiod_set_value_cansleep(panel->dc, 0);
usleep_range(1, 5);
pixpaper_spi_sync(panel->spi, &msg, err);
}
static void pixpaper_send_data(struct pixpaper_panel *panel, u8 data,
struct pixpaper_error_ctx *err)
{
if (err->errno_code)
return;
struct spi_transfer xfer = {
.tx_buf = &data,
.len = 1,
};
struct spi_message msg;
spi_message_init(&msg);
spi_message_add_tail(&xfer, &msg);
gpiod_set_value_cansleep(panel->dc, 1);
usleep_range(1, 5);
pixpaper_spi_sync(panel->spi, &msg, err);
}
static int pixpaper_panel_hw_init(struct pixpaper_panel *panel)
{
struct pixpaper_error_ctx err = { .errno_code = 0 };
gpiod_set_value_cansleep(panel->reset, 0);
msleep(50);
gpiod_set_value_cansleep(panel->reset, 1);
msleep(50);
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_UNKNOWN_4D, &err);
pixpaper_send_data(panel, PIXPAPER_UNKNOWN_4D_CONFIG, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_PANEL_SETTING, &err);
pixpaper_send_data(panel, PIXPAPER_PSR_CONFIG, &err);
pixpaper_send_data(panel, PIXPAPER_PSR_CONFIG2, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_POWER_SETTING, &err);
pixpaper_send_data(panel, PIXPAPER_PWR_CONFIG1, &err);
pixpaper_send_data(panel, PIXPAPER_PWR_CONFIG2, &err);
pixpaper_send_data(panel, PIXPAPER_PWR_VSP_8_2V, &err);
pixpaper_send_data(panel, PIXPAPER_PWR_VSPL_15V, &err);
pixpaper_send_data(panel, PIXPAPER_PWR_VSN_4V, &err);
pixpaper_send_data(panel, PIXPAPER_PWR_VSP_8_2V, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_POWER_OFF_SEQUENCE, &err);
pixpaper_send_data(panel, PIXPAPER_PFS_CONFIG1, &err);
pixpaper_send_data(panel, PIXPAPER_PFS_CONFIG2, &err);
pixpaper_send_data(panel, PIXPAPER_PFS_CONFIG3, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_BOOSTER_SOFT_START, &err);
pixpaper_send_data(panel, PIXPAPER_BTST_CONFIG1, &err);
pixpaper_send_data(panel, PIXPAPER_BTST_CONFIG2, &err);
pixpaper_send_data(panel, PIXPAPER_BTST_CONFIG3, &err);
pixpaper_send_data(panel, PIXPAPER_BTST_CONFIG4, &err);
pixpaper_send_data(panel, PIXPAPER_BTST_CONFIG5, &err);
pixpaper_send_data(panel, PIXPAPER_BTST_CONFIG6, &err);
pixpaper_send_data(panel, PIXPAPER_BTST_CONFIG7, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_PLL_CONTROL, &err);
pixpaper_send_data(panel, PIXPAPER_PLL_CONFIG, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_TEMP_SENSOR_CALIB, &err);
pixpaper_send_data(panel, PIXPAPER_TSE_CONFIG, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_VCOM_INTERVAL, &err);
pixpaper_send_data(panel, PIXPAPER_CDI_CONFIG, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_UNKNOWN_60, &err);
pixpaper_send_data(panel, PIXPAPER_UNKNOWN_60_CONFIG1, &err);
pixpaper_send_data(panel, PIXPAPER_UNKNOWN_60_CONFIG2, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_RESOLUTION_SETTING, &err);
pixpaper_send_data(panel, PIXPAPER_TRES_HRES_H, &err);
pixpaper_send_data(panel, PIXPAPER_TRES_HRES_L, &err);
pixpaper_send_data(panel, PIXPAPER_TRES_VRES_H, &err);
pixpaper_send_data(panel, PIXPAPER_TRES_VRES_L, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_GATE_SOURCE_START, &err);
pixpaper_send_data(panel, PIXPAPER_GSST_S_START, &err);
pixpaper_send_data(panel, PIXPAPER_GSST_RESERVED, &err);
pixpaper_send_data(panel, PIXPAPER_GSST_G_START_H, &err);
pixpaper_send_data(panel, PIXPAPER_GSST_G_START_L, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_UNKNOWN_E7, &err);
pixpaper_send_data(panel, PIXPAPER_UNKNOWN_E7_CONFIG, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_POWER_SAVING, &err);
pixpaper_send_data(panel, PIXPAPER_PWS_CONFIG, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_UNKNOWN_E0, &err);
pixpaper_send_data(panel, PIXPAPER_UNKNOWN_E0_CONFIG, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_UNKNOWN_B4, &err);
pixpaper_send_data(panel, PIXPAPER_UNKNOWN_B4_CONFIG, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_UNKNOWN_B5, &err);
pixpaper_send_data(panel, PIXPAPER_UNKNOWN_B5_CONFIG, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_UNKNOWN_E9, &err);
pixpaper_send_data(panel, PIXPAPER_UNKNOWN_E9_CONFIG, &err);
if (err.errno_code)
goto init_fail;
pixpaper_wait_for_panel(panel);
return 0;
init_fail:
drm_err(&panel->drm, "Hardware initialization failed (err=%d)\n",
err.errno_code);
return err.errno_code;
}
/*
* Convert framebuffer pixels to 2-bit e-paper format:
* 00 - White
* 01 - Black
* 10 - Yellow
* 11 - Red
*/
static u8 pack_pixels_to_byte(__le32 *src_pixels, int i, int j,
struct drm_framebuffer *fb)
{
u8 packed_byte = 0;
int k;
for (k = 0; k < 4; k++) {
int current_pixel_x = j * 4 + k;
u8 two_bit_val;
if (current_pixel_x < PIXPAPER_WIDTH) {
u32 pixel_offset =
(i * (fb->pitches[0] / 4)) + current_pixel_x;
u32 pixel = le32_to_cpu(src_pixels[pixel_offset]);
u32 r = (pixel >> 16) & 0xFF;
u32 g = (pixel >> 8) & 0xFF;
u32 b = pixel & 0xFF;
if (r < PIXPAPER_COLOR_THRESHOLD_LOW_CHANNEL &&
g < PIXPAPER_COLOR_THRESHOLD_LOW_CHANNEL &&
b < PIXPAPER_COLOR_THRESHOLD_LOW_CHANNEL) {
two_bit_val = 0b00;
} else if (r > PIXPAPER_COLOR_THRESHOLD_HIGH_CHANNEL &&
g > PIXPAPER_COLOR_THRESHOLD_HIGH_CHANNEL &&
b > PIXPAPER_COLOR_THRESHOLD_HIGH_CHANNEL) {
two_bit_val = 0b01;
} else if (r > PIXPAPER_COLOR_THRESHOLD_HIGH_CHANNEL &&
g < PIXPAPER_COLOR_THRESHOLD_LOW_CHANNEL &&
b < PIXPAPER_COLOR_THRESHOLD_LOW_CHANNEL) {
two_bit_val = 0b11;
} else if (r > PIXPAPER_COLOR_THRESHOLD_HIGH_CHANNEL &&
g > PIXPAPER_COLOR_THRESHOLD_YELLOW_MIN_GREEN &&
b < PIXPAPER_COLOR_THRESHOLD_LOW_CHANNEL) {
two_bit_val = 0b10;
} else {
two_bit_val = 0b01;
}
} else {
two_bit_val = 0b01;
}
packed_byte |= two_bit_val << ((3 - k) * 2);
}
return packed_byte;
}
static int pixpaper_plane_helper_atomic_check(struct drm_plane *plane,
struct drm_atomic_state *state)
{
struct drm_plane_state *new_plane_state =
drm_atomic_get_new_plane_state(state, plane);
struct drm_crtc *new_crtc = new_plane_state->crtc;
struct drm_crtc_state *new_crtc_state = NULL;
int ret;
if (new_crtc)
new_crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc);
ret = drm_atomic_helper_check_plane_state(new_plane_state,
new_crtc_state, DRM_PLANE_NO_SCALING,
DRM_PLANE_NO_SCALING, false, false);
if (ret)
return ret;
else if (!new_plane_state->visible)
return 0;
return 0;
}
static int pixpaper_crtc_helper_atomic_check(struct drm_crtc *crtc,
struct drm_atomic_state *state)
{
struct drm_crtc_state *crtc_state =
drm_atomic_get_new_crtc_state(state, crtc);
if (!crtc_state->enable)
return 0;
return drm_atomic_helper_check_crtc_primary_plane(crtc_state);
}
static void pixpaper_crtc_atomic_enable(struct drm_crtc *crtc,
struct drm_atomic_state *state)
{
struct pixpaper_panel *panel = to_pixpaper_panel(crtc->dev);
struct drm_device *drm = &panel->drm;
int idx;
struct pixpaper_error_ctx err = { .errno_code = 0 };
if (!drm_dev_enter(drm, &idx))
return;
pixpaper_send_cmd(panel, PIXPAPER_CMD_POWER_ON, &err);
if (err.errno_code) {
drm_err_once(drm, "Failed to send PON command: %d\n", err.errno_code);
goto exit_drm_dev;
}
pixpaper_wait_for_panel(panel);
drm_dbg(drm, "Panel enabled and powered on\n");
exit_drm_dev:
drm_dev_exit(idx);
}
static void pixpaper_crtc_atomic_disable(struct drm_crtc *crtc,
struct drm_atomic_state *state)
{
struct pixpaper_panel *panel = to_pixpaper_panel(crtc->dev);
struct drm_device *drm = &panel->drm;
struct pixpaper_error_ctx err = { .errno_code = 0 };
int idx;
if (!drm_dev_enter(drm, &idx))
return;
pixpaper_send_cmd(panel, PIXPAPER_CMD_POWER_OFF, &err);
if (err.errno_code) {
drm_err_once(drm, "Failed to send POF command: %d\n", err.errno_code);
goto exit_drm_dev;
}
pixpaper_wait_for_panel(panel);
drm_dbg(drm, "Panel disabled\n");
exit_drm_dev:
drm_dev_exit(idx);
}
static void pixpaper_plane_atomic_update(struct drm_plane *plane,
struct drm_atomic_state *state)
{
struct drm_plane_state *plane_state =
drm_atomic_get_new_plane_state(state, plane);
struct drm_shadow_plane_state *shadow_plane_state =
to_drm_shadow_plane_state(plane_state);
struct drm_crtc *crtc = plane_state->crtc;
struct pixpaper_panel *panel = to_pixpaper_panel(crtc->dev);
struct drm_device *drm = &panel->drm;
struct drm_framebuffer *fb = plane_state->fb;
struct iosys_map map = shadow_plane_state->data[0];
void *vaddr = map.vaddr;
int i, j, idx;
__le32 *src_pixels = NULL;
struct pixpaper_error_ctx err = { .errno_code = 0 };
if (!drm_dev_enter(drm, &idx))
return;
drm_dbg(drm, "Starting frame update (phys=%dx%d, buf_w=%d)\n",
PIXPAPER_WIDTH, PIXPAPER_HEIGHT, PIXPAPER_PANEL_BUFFER_WIDTH);
if (!fb || !plane_state->visible) {
drm_err_once(drm, "No framebuffer or plane not visible, skipping update\n");
goto update_cleanup;
}
src_pixels = (__le32 *)vaddr;
pixpaper_send_cmd(panel, PIXPAPER_CMD_DATA_START_TRANSMISSION, &err);
if (err.errno_code)
goto update_cleanup;
pixpaper_wait_for_panel(panel);
for (i = 0; i < PIXPAPER_HEIGHT; i++) {
for (j = 0; j < PIXPAPER_PANEL_BUFFER_TWO_BYTES_PER_ROW; j++) {
u8 packed_byte =
pack_pixels_to_byte(src_pixels, i, j, fb);
pixpaper_wait_for_panel(panel);
pixpaper_send_data(panel, packed_byte, &err);
}
}
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_POWER_ON, &err);
if (err.errno_code) {
drm_err_once(drm, "Failed to send PON command: %d\n", err.errno_code);
goto update_cleanup;
}
pixpaper_wait_for_panel(panel);
pixpaper_send_cmd(panel, PIXPAPER_CMD_DISPLAY_REFRESH, &err);
pixpaper_send_data(panel, PIXPAPER_DRF_VCOM_AC, &err);
if (err.errno_code) {
drm_err_once(drm, "Failed sending data after DRF: %d\n", err.errno_code);
goto update_cleanup;
}
pixpaper_wait_for_panel(panel);
update_cleanup:
if (err.errno_code && err.errno_code != -ETIMEDOUT)
drm_err_once(drm, "Frame update function failed with error %d\n", err.errno_code);
drm_dev_exit(idx);
}
static const struct drm_display_mode pixpaper_mode = {
.clock = PIXPAPER_PIXEL_CLOCK,
.hdisplay = PIXPAPER_WIDTH,
.hsync_start = PIXPAPER_WIDTH + PIXPAPER_HFP,
.hsync_end = PIXPAPER_WIDTH + PIXPAPER_HFP + PIXPAPER_HSYNC,
.htotal = PIXPAPER_HTOTAL,
.vdisplay = PIXPAPER_HEIGHT,
.vsync_start = PIXPAPER_HEIGHT + PIXPAPER_VFP,
.vsync_end = PIXPAPER_HEIGHT + PIXPAPER_VFP + PIXPAPER_VSYNC,
.vtotal = PIXPAPER_VTOTAL,
.width_mm = PIXPAPER_WIDTH_MM,
.height_mm = PIXPAPER_HEIGHT_MM,
.type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
};
static int pixpaper_connector_get_modes(struct drm_connector *connector)
{
return drm_connector_helper_get_modes_fixed(connector, &pixpaper_mode);
}
static const struct drm_plane_funcs pixpaper_plane_funcs = {
.update_plane = drm_atomic_helper_update_plane,
.disable_plane = drm_atomic_helper_disable_plane,
.destroy = drm_plane_cleanup,
DRM_GEM_SHADOW_PLANE_FUNCS,
};
static const struct drm_plane_helper_funcs pixpaper_plane_helper_funcs = {
DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
.atomic_check = pixpaper_plane_helper_atomic_check,
.atomic_update = pixpaper_plane_atomic_update,
};
static const struct drm_crtc_funcs pixpaper_crtc_funcs = {
.set_config = drm_atomic_helper_set_config,
.page_flip = drm_atomic_helper_page_flip,
.reset = drm_atomic_helper_crtc_reset,
.destroy = drm_crtc_cleanup,
.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
};
static enum drm_mode_status
pixpaper_mode_valid(struct drm_crtc *crtc, const struct drm_display_mode *mode)
{
if (mode->hdisplay == PIXPAPER_WIDTH &&
mode->vdisplay == PIXPAPER_HEIGHT) {
return MODE_OK;
}
return MODE_BAD;
}
static const struct drm_crtc_helper_funcs pixpaper_crtc_helper_funcs = {
.mode_valid = pixpaper_mode_valid,
.atomic_check = pixpaper_crtc_helper_atomic_check,
.atomic_enable = pixpaper_crtc_atomic_enable,
.atomic_disable = pixpaper_crtc_atomic_disable,
};
static const struct drm_encoder_funcs pixpaper_encoder_funcs = {
.destroy = drm_encoder_cleanup,
};
static const struct drm_connector_funcs pixpaper_connector_funcs = {
.reset = drm_atomic_helper_connector_reset,
.fill_modes = drm_helper_probe_single_connector_modes,
.destroy = drm_connector_cleanup,
.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
};
static const struct drm_connector_helper_funcs pixpaper_connector_helper_funcs = {
.get_modes = pixpaper_connector_get_modes,
};
DEFINE_DRM_GEM_FOPS(pixpaper_fops);
static struct drm_driver pixpaper_drm_driver = {
.driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
.fops = &pixpaper_fops,
.name = "pixpaper",
.desc = "DRM driver for PIXPAPER e-ink",
.major = 1,
.minor = 0,
DRM_GEM_SHMEM_DRIVER_OPS,
DRM_FBDEV_SHMEM_DRIVER_OPS,
};
static const struct drm_mode_config_funcs pixpaper_mode_config_funcs = {
.fb_create = drm_gem_fb_create_with_dirty,
.atomic_check = drm_atomic_helper_check,
.atomic_commit = drm_atomic_helper_commit,
};
static int pixpaper_probe(struct spi_device *spi)
{
struct device *dev = &spi->dev;
struct pixpaper_panel *panel;
struct drm_device *drm;
int ret;
panel = devm_drm_dev_alloc(dev, &pixpaper_drm_driver,
struct pixpaper_panel, drm);
if (IS_ERR(panel))
return PTR_ERR(panel);
drm = &panel->drm;
panel->spi = spi;
spi_set_drvdata(spi, panel);
spi->mode = SPI_MODE_0;
spi->bits_per_word = PIXPAPER_SPI_BITS_PER_WORD;
if (!spi->max_speed_hz) {
drm_warn(drm,
"spi-max-frequency not specified in DT, using default %u Hz\n",
PIXPAPER_SPI_SPEED_DEFAULT);
spi->max_speed_hz = PIXPAPER_SPI_SPEED_DEFAULT;
}
ret = spi_setup(spi);
if (ret < 0) {
drm_err(drm, "SPI setup failed: %d\n", ret);
return ret;
}
if (!dev->dma_mask)
dev->dma_mask = &dev->coherent_dma_mask;
ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
if (ret) {
drm_err(drm, "Failed to set DMA mask: %d\n", ret);
return ret;
}
panel->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(panel->reset))
return PTR_ERR(panel->reset);
panel->busy = devm_gpiod_get(dev, "busy", GPIOD_IN);
if (IS_ERR(panel->busy))
return PTR_ERR(panel->busy);
panel->dc = devm_gpiod_get(dev, "dc", GPIOD_OUT_HIGH);
if (IS_ERR(panel->dc))
return PTR_ERR(panel->dc);
ret = pixpaper_panel_hw_init(panel);
if (ret) {
drm_err(drm, "Panel hardware initialization failed: %d\n", ret);
return ret;
}
ret = drmm_mode_config_init(drm);
if (ret)
return ret;
drm->mode_config.funcs = &pixpaper_mode_config_funcs;
drm->mode_config.min_width = PIXPAPER_WIDTH;
drm->mode_config.max_width = PIXPAPER_WIDTH;
drm->mode_config.min_height = PIXPAPER_HEIGHT;
drm->mode_config.max_height = PIXPAPER_HEIGHT;
ret = drm_universal_plane_init(drm, &panel->plane, 1,
&pixpaper_plane_funcs,
(const uint32_t[]){ DRM_FORMAT_XRGB8888 },
1, NULL, DRM_PLANE_TYPE_PRIMARY, NULL);
if (ret)
return ret;
drm_plane_helper_add(&panel->plane, &pixpaper_plane_helper_funcs);
ret = drm_crtc_init_with_planes(drm, &panel->crtc, &panel->plane, NULL,
&pixpaper_crtc_funcs, NULL);
if (ret)
return ret;
drm_crtc_helper_add(&panel->crtc, &pixpaper_crtc_helper_funcs);
ret = drm_encoder_init(drm, &panel->encoder, &pixpaper_encoder_funcs,
DRM_MODE_ENCODER_NONE, NULL);
if (ret)
return ret;
panel->encoder.possible_crtcs = drm_crtc_mask(&panel->crtc);
ret = drm_connector_init(drm, &panel->connector,
&pixpaper_connector_funcs,
DRM_MODE_CONNECTOR_SPI);
if (ret)
return ret;
drm_connector_helper_add(&panel->connector,
&pixpaper_connector_helper_funcs);
drm_connector_attach_encoder(&panel->connector, &panel->encoder);
drm_mode_config_reset(drm);
ret = drm_dev_register(drm, 0);
if (ret)
return ret;
drm_client_setup(drm, NULL);
return 0;
}
static void pixpaper_remove(struct spi_device *spi)
{
struct pixpaper_panel *panel = spi_get_drvdata(spi);
if (!panel)
return;
drm_dev_unplug(&panel->drm);
drm_atomic_helper_shutdown(&panel->drm);
}
static const struct spi_device_id pixpaper_ids[] = { { "pixpaper", 0 }, {} };
MODULE_DEVICE_TABLE(spi, pixpaper_ids);
static const struct of_device_id pixpaper_dt_ids[] = {
{ .compatible = "mayqueen,pixpaper" },
{}
};
MODULE_DEVICE_TABLE(of, pixpaper_dt_ids);
static struct spi_driver pixpaper_spi_driver = {
.driver = {
.name = "pixpaper",
.of_match_table = pixpaper_dt_ids,
},
.id_table = pixpaper_ids,
.probe = pixpaper_probe,
.remove = pixpaper_remove,
};
module_spi_driver(pixpaper_spi_driver);
MODULE_AUTHOR("LiangCheng Wang");
MODULE_DESCRIPTION("DRM SPI driver for PIXPAPER e-ink panel");
MODULE_LICENSE("GPL");
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