diff options
Diffstat (limited to 'drivers/video/ssd2828.c')
| -rw-r--r-- | drivers/video/ssd2828.c | 422 |
1 files changed, 422 insertions, 0 deletions
diff --git a/drivers/video/ssd2828.c b/drivers/video/ssd2828.c new file mode 100644 index 0000000..be68d38 --- /dev/null +++ b/drivers/video/ssd2828.c @@ -0,0 +1,422 @@ +/* + * (C) 2015 Siarhei Siamashka <siarhei.siamashka@gmail.com> + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +/* + * Support for the SSD2828 bridge chip, which can take pixel data coming + * from a parallel LCD interface and translate it on the flight into MIPI DSI + * interface for driving a MIPI compatible TFT display. + */ + +#include <common.h> +#include <mipi_display.h> +#include <asm/arch/gpio.h> +#include <asm/gpio.h> + +#include "videomodes.h" +#include "ssd2828.h" + +#define SSD2828_DIR 0xB0 +#define SSD2828_VICR1 0xB1 +#define SSD2828_VICR2 0xB2 +#define SSD2828_VICR3 0xB3 +#define SSD2828_VICR4 0xB4 +#define SSD2828_VICR5 0xB5 +#define SSD2828_VICR6 0xB6 +#define SSD2828_CFGR 0xB7 +#define SSD2828_VCR 0xB8 +#define SSD2828_PCR 0xB9 +#define SSD2828_PLCR 0xBA +#define SSD2828_CCR 0xBB +#define SSD2828_PSCR1 0xBC +#define SSD2828_PSCR2 0xBD +#define SSD2828_PSCR3 0xBE +#define SSD2828_PDR 0xBF +#define SSD2828_OCR 0xC0 +#define SSD2828_MRSR 0xC1 +#define SSD2828_RDCR 0xC2 +#define SSD2828_ARSR 0xC3 +#define SSD2828_LCR 0xC4 +#define SSD2828_ICR 0xC5 +#define SSD2828_ISR 0xC6 +#define SSD2828_ESR 0xC7 +#define SSD2828_DAR1 0xC9 +#define SSD2828_DAR2 0xCA +#define SSD2828_DAR3 0xCB +#define SSD2828_DAR4 0xCC +#define SSD2828_DAR5 0xCD +#define SSD2828_DAR6 0xCE +#define SSD2828_HTTR1 0xCF +#define SSD2828_HTTR2 0xD0 +#define SSD2828_LRTR1 0xD1 +#define SSD2828_LRTR2 0xD2 +#define SSD2828_TSR 0xD3 +#define SSD2828_LRR 0xD4 +#define SSD2828_PLLR 0xD5 +#define SSD2828_TR 0xD6 +#define SSD2828_TECR 0xD7 +#define SSD2828_ACR1 0xD8 +#define SSD2828_ACR2 0xD9 +#define SSD2828_ACR3 0xDA +#define SSD2828_ACR4 0xDB +#define SSD2828_IOCR 0xDC +#define SSD2828_VICR7 0xDD +#define SSD2828_LCFR 0xDE +#define SSD2828_DAR7 0xDF +#define SSD2828_PUCR1 0xE0 +#define SSD2828_PUCR2 0xE1 +#define SSD2828_PUCR3 0xE2 +#define SSD2828_CBCR1 0xE9 +#define SSD2828_CBCR2 0xEA +#define SSD2828_CBSR 0xEB +#define SSD2828_ECR 0xEC +#define SSD2828_VSDR 0xED +#define SSD2828_TMR 0xEE +#define SSD2828_GPIO1 0xEF +#define SSD2828_GPIO2 0xF0 +#define SSD2828_DLYA01 0xF1 +#define SSD2828_DLYA23 0xF2 +#define SSD2828_DLYB01 0xF3 +#define SSD2828_DLYB23 0xF4 +#define SSD2828_DLYC01 0xF5 +#define SSD2828_DLYC23 0xF6 +#define SSD2828_ACR5 0xF7 +#define SSD2828_RR 0xFF + +#define SSD2828_CFGR_HS (1 << 0) +#define SSD2828_CFGR_CKE (1 << 1) +#define SSD2828_CFGR_SLP (1 << 2) +#define SSD2828_CFGR_VEN (1 << 3) +#define SSD2828_CFGR_HCLK (1 << 4) +#define SSD2828_CFGR_CSS (1 << 5) +#define SSD2828_CFGR_DCS (1 << 6) +#define SSD2828_CFGR_REN (1 << 7) +#define SSD2828_CFGR_ECD (1 << 8) +#define SSD2828_CFGR_EOT (1 << 9) +#define SSD2828_CFGR_LPE (1 << 10) +#define SSD2828_CFGR_TXD (1 << 11) + +#define SSD2828_VIDEO_MODE_NON_BURST_WITH_SYNC_PULSES (0 << 2) +#define SSD2828_VIDEO_MODE_NON_BURST_WITH_SYNC_EVENTS (1 << 2) +#define SSD2828_VIDEO_MODE_BURST (2 << 2) + +#define SSD2828_VIDEO_PIXEL_FORMAT_16BPP 0 +#define SSD2828_VIDEO_PIXEL_FORMAT_18BPP_PACKED 1 +#define SSD2828_VIDEO_PIXEL_FORMAT_18BPP_LOOSELY_PACKED 2 +#define SSD2828_VIDEO_PIXEL_FORMAT_24BPP 3 + +#define SSD2828_LP_CLOCK_DIVIDER(n) (((n) - 1) & 0x3F) + +/* + * SPI transfer, using the "24-bit 3 wire" mode (that's how it is called in + * the SSD2828 documentation). The 'dout' input parameter specifies 24-bits + * of data to be written to SSD2828. Returns the lowest 16-bits of data, + * that is received back. + */ +static u32 soft_spi_xfer_24bit_3wire(const struct ssd2828_config *drv, u32 dout) +{ + int j, bitlen = 24; + u32 tmpdin = 0; + /* + * According to the "24 Bit 3 Wire SPI Interface Timing Characteristics" + * and "TX_CLK Timing Characteristics" tables in the SSD2828 datasheet, + * the lowest possible 'tx_clk' clock frequency is 8MHz, and SPI runs + * at 1/8 of that after reset. So using 1 microsecond delays is safe in + * the main loop. But the delays around chip select pin manipulations + * need to be longer (up to 16 'tx_clk' cycles, or 2 microseconds in + * the worst case). + */ + const int spi_delay_us = 1; + const int spi_cs_delay_us = 2; + + gpio_set_value(drv->csx_pin, 0); + udelay(spi_cs_delay_us); + for (j = bitlen - 1; j >= 0; j--) { + gpio_set_value(drv->sck_pin, 0); + gpio_set_value(drv->sdi_pin, (dout & (1 << j)) != 0); + udelay(spi_delay_us); + if (drv->sdo_pin != -1) + tmpdin = (tmpdin << 1) | gpio_get_value(drv->sdo_pin); + gpio_set_value(drv->sck_pin, 1); + udelay(spi_delay_us); + } + udelay(spi_cs_delay_us); + gpio_set_value(drv->csx_pin, 1); + udelay(spi_cs_delay_us); + return tmpdin & 0xFFFF; +} + +/* + * Read from a SSD2828 hardware register (regnum >= 0xB0) + */ +static u32 read_hw_register(const struct ssd2828_config *cfg, u8 regnum) +{ + soft_spi_xfer_24bit_3wire(cfg, 0x700000 | regnum); + return soft_spi_xfer_24bit_3wire(cfg, 0x730000); +} + +/* + * Write to a SSD2828 hardware register (regnum >= 0xB0) + */ +static void write_hw_register(const struct ssd2828_config *cfg, u8 regnum, + u16 val) +{ + soft_spi_xfer_24bit_3wire(cfg, 0x700000 | regnum); + soft_spi_xfer_24bit_3wire(cfg, 0x720000 | val); +} + +/* + * Send MIPI command to the LCD panel (cmdnum < 0xB0) + */ +static void send_mipi_dcs_command(const struct ssd2828_config *cfg, u8 cmdnum) +{ + /* Set packet size to 1 (a single command with no parameters) */ + write_hw_register(cfg, SSD2828_PSCR1, 1); + /* Send the command */ + write_hw_register(cfg, SSD2828_PDR, cmdnum); +} + +/* + * Reset SSD2828 + */ +static void ssd2828_reset(const struct ssd2828_config *cfg) +{ + /* RESET needs 10 milliseconds according to the datasheet */ + gpio_set_value(cfg->reset_pin, 0); + mdelay(10); + gpio_set_value(cfg->reset_pin, 1); + mdelay(10); +} + +static int ssd2828_enable_gpio(const struct ssd2828_config *cfg) +{ + if (gpio_request(cfg->csx_pin, "ssd2828_csx")) { + printf("SSD2828: request for 'ssd2828_csx' pin failed\n"); + return 1; + } + if (gpio_request(cfg->sck_pin, "ssd2828_sck")) { + gpio_free(cfg->csx_pin); + printf("SSD2828: request for 'ssd2828_sck' pin failed\n"); + return 1; + } + if (gpio_request(cfg->sdi_pin, "ssd2828_sdi")) { + gpio_free(cfg->csx_pin); + gpio_free(cfg->sck_pin); + printf("SSD2828: request for 'ssd2828_sdi' pin failed\n"); + return 1; + } + if (gpio_request(cfg->reset_pin, "ssd2828_reset")) { + gpio_free(cfg->csx_pin); + gpio_free(cfg->sck_pin); + gpio_free(cfg->sdi_pin); + printf("SSD2828: request for 'ssd2828_reset' pin failed\n"); + return 1; + } + if (cfg->sdo_pin != -1 && gpio_request(cfg->sdo_pin, "ssd2828_sdo")) { + gpio_free(cfg->csx_pin); + gpio_free(cfg->sck_pin); + gpio_free(cfg->sdi_pin); + gpio_free(cfg->reset_pin); + printf("SSD2828: request for 'ssd2828_sdo' pin failed\n"); + return 1; + } + gpio_direction_output(cfg->reset_pin, 0); + gpio_direction_output(cfg->csx_pin, 1); + gpio_direction_output(cfg->sck_pin, 1); + gpio_direction_output(cfg->sdi_pin, 1); + if (cfg->sdo_pin != -1) + gpio_direction_input(cfg->sdo_pin); + + return 0; +} + +static int ssd2828_free_gpio(const struct ssd2828_config *cfg) +{ + gpio_free(cfg->csx_pin); + gpio_free(cfg->sck_pin); + gpio_free(cfg->sdi_pin); + gpio_free(cfg->reset_pin); + if (cfg->sdo_pin != -1) + gpio_free(cfg->sdo_pin); + return 1; +} + +/* + * PLL configuration register settings. + * + * See the "PLL Configuration Register Description" in the SSD2828 datasheet. + */ +static u32 construct_pll_config(u32 desired_pll_freq_kbps, + u32 reference_freq_khz) +{ + u32 div_factor = 1, mul_factor, fr = 0; + u32 output_freq_kbps; + + /* The intermediate clock after division can't be less than 5MHz */ + while (reference_freq_khz / (div_factor + 1) >= 5000) + div_factor++; + if (div_factor > 31) + div_factor = 31; + + mul_factor = DIV_ROUND_UP(desired_pll_freq_kbps * div_factor, + reference_freq_khz); + + output_freq_kbps = reference_freq_khz * mul_factor / div_factor; + + if (output_freq_kbps >= 501000) + fr = 3; + else if (output_freq_kbps >= 251000) + fr = 2; + else if (output_freq_kbps >= 126000) + fr = 1; + + return (fr << 14) | (div_factor << 8) | mul_factor; +} + +static u32 decode_pll_config(u32 pll_config, u32 reference_freq_khz) +{ + u32 mul_factor = pll_config & 0xFF; + u32 div_factor = (pll_config >> 8) & 0x1F; + if (mul_factor == 0) + mul_factor = 1; + if (div_factor == 0) + div_factor = 1; + return reference_freq_khz * mul_factor / div_factor; +} + +static int ssd2828_configure_video_interface(const struct ssd2828_config *cfg, + const struct ctfb_res_modes *mode) +{ + u32 val; + + /* RGB Interface Control Register 1 */ + write_hw_register(cfg, SSD2828_VICR1, (mode->vsync_len << 8) | + (mode->hsync_len)); + + /* RGB Interface Control Register 2 */ + u32 vbp = mode->vsync_len + mode->upper_margin; + u32 hbp = mode->hsync_len + mode->left_margin; + write_hw_register(cfg, SSD2828_VICR2, (vbp << 8) | hbp); + + /* RGB Interface Control Register 3 */ + write_hw_register(cfg, SSD2828_VICR3, (mode->lower_margin << 8) | + (mode->right_margin)); + + /* RGB Interface Control Register 4 */ + write_hw_register(cfg, SSD2828_VICR4, mode->xres); + + /* RGB Interface Control Register 5 */ + write_hw_register(cfg, SSD2828_VICR5, mode->yres); + + /* RGB Interface Control Register 6 */ + val = SSD2828_VIDEO_MODE_BURST; + switch (cfg->ssd2828_color_depth) { + case 16: + val |= SSD2828_VIDEO_PIXEL_FORMAT_16BPP; + break; + case 18: + val |= cfg->mipi_dsi_loosely_packed_pixel_format ? + SSD2828_VIDEO_PIXEL_FORMAT_18BPP_LOOSELY_PACKED : + SSD2828_VIDEO_PIXEL_FORMAT_18BPP_PACKED; + break; + case 24: + val |= SSD2828_VIDEO_PIXEL_FORMAT_24BPP; + break; + default: + printf("SSD2828: unsupported color depth\n"); + return 1; + } + write_hw_register(cfg, SSD2828_VICR6, val); + + /* Lane Configuration Register */ + write_hw_register(cfg, SSD2828_LCFR, + cfg->mipi_dsi_number_of_data_lanes - 1); + + return 0; +} + +int ssd2828_init(const struct ssd2828_config *cfg, + const struct ctfb_res_modes *mode) +{ + u32 lp_div, pll_freq_kbps, pll_config; + /* The LP clock speed is limited by 10MHz */ + const u32 mipi_dsi_low_power_clk_khz = 10000; + /* + * This is just the reset default value of CFGR register (0x301). + * Because we are not always able to read back from SPI, have + * it initialized here. + */ + u32 cfgr_reg = SSD2828_CFGR_EOT | /* EOT Packet Enable */ + SSD2828_CFGR_ECD | /* Disable ECC and CRC */ + SSD2828_CFGR_HS; /* Data lanes are in HS mode */ + + /* Initialize the pins */ + if (ssd2828_enable_gpio(cfg) != 0) + return 1; + + /* Reset the chip */ + ssd2828_reset(cfg); + + /* + * If there is a pin to read data back from SPI, then we are lucky. Try + * to check if SPI is configured correctly and SSD2828 is actually able + * to talk back. + */ + if (cfg->sdo_pin != -1) { + if (read_hw_register(cfg, SSD2828_DIR) != 0x2828 || + read_hw_register(cfg, SSD2828_CFGR) != cfgr_reg) { + printf("SSD2828: SPI communication failed.\n"); + ssd2828_free_gpio(cfg); + return 1; + } + } + + /* + * Setup the parallel LCD timings in the appropriate registers. + */ + if (ssd2828_configure_video_interface(cfg, mode) != 0) { + ssd2828_free_gpio(cfg); + return 1; + } + + /* Configuration Register */ + cfgr_reg &= ~SSD2828_CFGR_HS; /* Data lanes are in LP mode */ + cfgr_reg |= SSD2828_CFGR_CKE; /* Clock lane is in HS mode */ + cfgr_reg |= SSD2828_CFGR_DCS; /* Only use DCS packets */ + write_hw_register(cfg, SSD2828_CFGR, cfgr_reg); + + /* PLL Configuration Register */ + pll_config = construct_pll_config( + cfg->mipi_dsi_bitrate_per_data_lane_mbps * 1000, + cfg->ssd2828_tx_clk_khz); + write_hw_register(cfg, SSD2828_PLCR, pll_config); + + pll_freq_kbps = decode_pll_config(pll_config, cfg->ssd2828_tx_clk_khz); + lp_div = DIV_ROUND_UP(pll_freq_kbps, mipi_dsi_low_power_clk_khz * 8); + + /* VC Control Register */ + write_hw_register(cfg, SSD2828_VCR, 0); + + /* Clock Control Register */ + write_hw_register(cfg, SSD2828_CCR, SSD2828_LP_CLOCK_DIVIDER(lp_div)); + + /* PLL Control Register */ + write_hw_register(cfg, SSD2828_PCR, 1); /* Enable PLL */ + + /* Wait for PLL lock */ + udelay(500); + + send_mipi_dcs_command(cfg, MIPI_DCS_EXIT_SLEEP_MODE); + mdelay(cfg->mipi_dsi_delay_after_exit_sleep_mode_ms); + + send_mipi_dcs_command(cfg, MIPI_DCS_SET_DISPLAY_ON); + mdelay(cfg->mipi_dsi_delay_after_set_display_on_ms); + + cfgr_reg |= SSD2828_CFGR_HS; /* Enable HS mode for data lanes */ + cfgr_reg |= SSD2828_CFGR_VEN; /* Enable video pipeline */ + write_hw_register(cfg, SSD2828_CFGR, cfgr_reg); + + return 0; +} |