root/drivers/video/fbdev/wm8505fb.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  WonderMedia WM8505 Frame Buffer device driver
 *
 *  Copyright (C) 2010 Ed Spiridonov <edo.rus@gmail.com>
 *    Based on vt8500lcdfb.c
 */

#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/fb.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/wait.h>
#include <video/of_display_timing.h>

#include "wm8505fb_regs.h"
#include "wmt_ge_rops.h"

#define DRIVER_NAME "wm8505-fb"

#define to_wm8505fb_info(__info) container_of(__info, \
                                                struct wm8505fb_info, fb)
struct wm8505fb_info {
        struct fb_info          fb;
        void __iomem            *regbase;
        unsigned int            contrast;
};


static int wm8505fb_init_hw(struct fb_info *info)
{
        struct wm8505fb_info *fbi = to_wm8505fb_info(info);

        int i;

        /* I know the purpose only of few registers, so clear unknown */
        for (i = 0; i < 0x200; i += 4)
                writel(0, fbi->regbase + i);

        /* Set frame buffer address */
        writel(fbi->fb.fix.smem_start, fbi->regbase + WMT_GOVR_FBADDR);
        writel(fbi->fb.fix.smem_start, fbi->regbase + WMT_GOVR_FBADDR1);

        /*
         * Set in-memory picture format to RGB
         * 0x31C sets the correct color mode (RGB565) for WM8650
         * Bit 8+9 (0x300) are ignored on WM8505 as reserved
         */
        writel(0x31c,                  fbi->regbase + WMT_GOVR_COLORSPACE);
        writel(1,                      fbi->regbase + WMT_GOVR_COLORSPACE1);

        /* Virtual buffer size */
        writel(info->var.xres,         fbi->regbase + WMT_GOVR_XRES);
        writel(info->var.xres_virtual, fbi->regbase + WMT_GOVR_XRES_VIRTUAL);

        /* black magic ;) */
        writel(0xf,                    fbi->regbase + WMT_GOVR_FHI);
        writel(4,                      fbi->regbase + WMT_GOVR_DVO_SET);
        writel(1,                      fbi->regbase + WMT_GOVR_MIF_ENABLE);
        writel(1,                      fbi->regbase + WMT_GOVR_REG_UPDATE);

        return 0;
}

static int wm8505fb_set_timing(struct fb_info *info)
{
        struct wm8505fb_info *fbi = to_wm8505fb_info(info);

        int h_start = info->var.left_margin;
        int h_end = h_start + info->var.xres;
        int h_all = h_end + info->var.right_margin;
        int h_sync = info->var.hsync_len;

        int v_start = info->var.upper_margin;
        int v_end = v_start + info->var.yres;
        int v_all = v_end + info->var.lower_margin;
        int v_sync = info->var.vsync_len;

        writel(0, fbi->regbase + WMT_GOVR_TG);

        writel(h_start, fbi->regbase + WMT_GOVR_TIMING_H_START);
        writel(h_end,   fbi->regbase + WMT_GOVR_TIMING_H_END);
        writel(h_all,   fbi->regbase + WMT_GOVR_TIMING_H_ALL);
        writel(h_sync,  fbi->regbase + WMT_GOVR_TIMING_H_SYNC);

        writel(v_start, fbi->regbase + WMT_GOVR_TIMING_V_START);
        writel(v_end,   fbi->regbase + WMT_GOVR_TIMING_V_END);
        writel(v_all,   fbi->regbase + WMT_GOVR_TIMING_V_ALL);
        writel(v_sync,  fbi->regbase + WMT_GOVR_TIMING_V_SYNC);

        writel(1, fbi->regbase + WMT_GOVR_TG);

        return 0;
}


static int wm8505fb_set_par(struct fb_info *info)
{
        struct wm8505fb_info *fbi = to_wm8505fb_info(info);

        if (!fbi)
                return -EINVAL;

        if (info->var.bits_per_pixel == 32) {
                info->var.red.offset = 16;
                info->var.red.length = 8;
                info->var.red.msb_right = 0;
                info->var.green.offset = 8;
                info->var.green.length = 8;
                info->var.green.msb_right = 0;
                info->var.blue.offset = 0;
                info->var.blue.length = 8;
                info->var.blue.msb_right = 0;
                info->fix.visual = FB_VISUAL_TRUECOLOR;
                info->fix.line_length = info->var.xres_virtual << 2;
        } else if (info->var.bits_per_pixel == 16) {
                info->var.red.offset = 11;
                info->var.red.length = 5;
                info->var.red.msb_right = 0;
                info->var.green.offset = 5;
                info->var.green.length = 6;
                info->var.green.msb_right = 0;
                info->var.blue.offset = 0;
                info->var.blue.length = 5;
                info->var.blue.msb_right = 0;
                info->fix.visual = FB_VISUAL_TRUECOLOR;
                info->fix.line_length = info->var.xres_virtual << 1;
        }

        wm8505fb_set_timing(info);

        writel(fbi->contrast<<16 | fbi->contrast<<8 | fbi->contrast,
                fbi->regbase + WMT_GOVR_CONTRAST);

        return 0;
}

static ssize_t contrast_show(struct device *dev,
                             struct device_attribute *attr, char *buf)
{
        struct fb_info *info = dev_get_drvdata(dev);
        struct wm8505fb_info *fbi = to_wm8505fb_info(info);

        return sprintf(buf, "%u\n", fbi->contrast);
}

static ssize_t contrast_store(struct device *dev,
                              struct device_attribute *attr,
                              const char *buf, size_t count)
{
        struct fb_info *info = dev_get_drvdata(dev);
        struct wm8505fb_info *fbi = to_wm8505fb_info(info);
        unsigned long tmp;

        if (kstrtoul(buf, 10, &tmp) || (tmp > 0xff))
                return -EINVAL;
        fbi->contrast = tmp;

        wm8505fb_set_par(info);

        return count;
}

static DEVICE_ATTR_RW(contrast);

static struct attribute *wm8505fb_attrs[] = {
        &dev_attr_contrast.attr,
        NULL,
};
ATTRIBUTE_GROUPS(wm8505fb);

static inline u_int chan_to_field(u_int chan, struct fb_bitfield *bf)
{
        chan &= 0xffff;
        chan >>= 16 - bf->length;
        return chan << bf->offset;
}

static int wm8505fb_setcolreg(unsigned regno, unsigned red, unsigned green,
                           unsigned blue, unsigned transp,
                           struct fb_info *info) {
        struct wm8505fb_info *fbi = to_wm8505fb_info(info);
        int ret = 1;
        unsigned int val;
        if (regno >= 256)
                return -EINVAL;

        if (info->var.grayscale)
                red = green = blue =
                        (19595 * red + 38470 * green + 7471 * blue) >> 16;

        switch (fbi->fb.fix.visual) {
        case FB_VISUAL_TRUECOLOR:
                if (regno < 16) {
                        u32 *pal = info->pseudo_palette;

                        val  = chan_to_field(red, &fbi->fb.var.red);
                        val |= chan_to_field(green, &fbi->fb.var.green);
                        val |= chan_to_field(blue, &fbi->fb.var.blue);

                        pal[regno] = val;
                        ret = 0;
                }
                break;
        }

        return ret;
}

static int wm8505fb_pan_display(struct fb_var_screeninfo *var,
                                struct fb_info *info)
{
        struct wm8505fb_info *fbi = to_wm8505fb_info(info);

        writel(var->xoffset, fbi->regbase + WMT_GOVR_XPAN);
        writel(var->yoffset, fbi->regbase + WMT_GOVR_YPAN);
        return 0;
}

static int wm8505fb_blank(int blank, struct fb_info *info)
{
        struct wm8505fb_info *fbi = to_wm8505fb_info(info);

        switch (blank) {
        case FB_BLANK_UNBLANK:
                wm8505fb_set_timing(info);
                break;
        default:
                writel(0,  fbi->regbase + WMT_GOVR_TIMING_V_SYNC);
                break;
        }

        return 0;
}

static const struct fb_ops wm8505fb_ops = {
        .owner          = THIS_MODULE,
        __FB_DEFAULT_DMAMEM_OPS_RDWR,
        .fb_set_par     = wm8505fb_set_par,
        .fb_setcolreg   = wm8505fb_setcolreg,
        .fb_fillrect    = wmt_ge_fillrect,
        .fb_copyarea    = wmt_ge_copyarea,
        .fb_imageblit   = sys_imageblit,
        .fb_sync        = wmt_ge_sync,
        .fb_pan_display = wm8505fb_pan_display,
        .fb_blank       = wm8505fb_blank,
        __FB_DEFAULT_IOMEM_OPS_MMAP,
};

static int wm8505fb_probe(struct platform_device *pdev)
{
        struct wm8505fb_info    *fbi;
        struct display_timings *disp_timing;
        void                    *addr;
        int ret;

        struct fb_videomode     mode;
        u32                     bpp;
        dma_addr_t fb_mem_phys;
        unsigned long fb_mem_len;
        void *fb_mem_virt;

        fbi = devm_kzalloc(&pdev->dev, sizeof(struct wm8505fb_info) +
                        sizeof(u32) * 16, GFP_KERNEL);
        if (!fbi)
                return -ENOMEM;

        strcpy(fbi->fb.fix.id, DRIVER_NAME);

        fbi->fb.fix.type        = FB_TYPE_PACKED_PIXELS;
        fbi->fb.fix.xpanstep    = 1;
        fbi->fb.fix.ypanstep    = 1;
        fbi->fb.fix.ywrapstep   = 0;
        fbi->fb.fix.accel       = FB_ACCEL_NONE;

        fbi->fb.fbops           = &wm8505fb_ops;
        fbi->fb.flags           = FBINFO_HWACCEL_COPYAREA
                                | FBINFO_HWACCEL_FILLRECT
                                | FBINFO_HWACCEL_XPAN
                                | FBINFO_HWACCEL_YPAN
                                | FBINFO_VIRTFB
                                | FBINFO_PARTIAL_PAN_OK;
        fbi->fb.node            = -1;

        addr = fbi;
        addr = addr + sizeof(struct wm8505fb_info);
        fbi->fb.pseudo_palette  = addr;

        fbi->regbase = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(fbi->regbase))
                return PTR_ERR(fbi->regbase);

        disp_timing = of_get_display_timings(pdev->dev.of_node);
        if (!disp_timing)
                return -EINVAL;

        ret = of_get_fb_videomode(pdev->dev.of_node, &mode, OF_USE_NATIVE_MODE);
        if (ret)
                return ret;

        ret = of_property_read_u32(pdev->dev.of_node, "bits-per-pixel", &bpp);
        if (ret)
                return ret;

        fb_videomode_to_var(&fbi->fb.var, &mode);

        fbi->fb.var.nonstd              = 0;
        fbi->fb.var.activate            = FB_ACTIVATE_NOW;

        fbi->fb.var.height              = -1;
        fbi->fb.var.width               = -1;

        /* try allocating the framebuffer */
        fb_mem_len = mode.xres * mode.yres * 2 * (bpp / 8);
        fb_mem_virt = dmam_alloc_coherent(&pdev->dev, fb_mem_len, &fb_mem_phys,
                                GFP_KERNEL);
        if (!fb_mem_virt) {
                pr_err("%s: Failed to allocate framebuffer\n", __func__);
                return -ENOMEM;
        }

        fbi->fb.var.xres_virtual        = mode.xres;
        fbi->fb.var.yres_virtual        = mode.yres * 2;
        fbi->fb.var.bits_per_pixel      = bpp;

        fbi->fb.fix.smem_start          = fb_mem_phys;
        fbi->fb.fix.smem_len            = fb_mem_len;
        fbi->fb.screen_buffer           = fb_mem_virt;
        fbi->fb.screen_size             = fb_mem_len;

        fbi->contrast = 0x10;
        ret = wm8505fb_set_par(&fbi->fb);
        if (ret) {
                dev_err(&pdev->dev, "Failed to set parameters\n");
                return ret;
        }

        if (fb_alloc_cmap(&fbi->fb.cmap, 256, 0) < 0) {
                dev_err(&pdev->dev, "Failed to allocate color map\n");
                return -ENOMEM;
        }

        wm8505fb_init_hw(&fbi->fb);

        platform_set_drvdata(pdev, fbi);

        ret = register_framebuffer(&fbi->fb);
        if (ret < 0) {
                dev_err(&pdev->dev,
                        "Failed to register framebuffer device: %d\n", ret);
                if (fbi->fb.cmap.len)
                        fb_dealloc_cmap(&fbi->fb.cmap);
                return ret;
        }

        fb_info(&fbi->fb, "%s frame buffer at 0x%lx-0x%lx\n",
                fbi->fb.fix.id, fbi->fb.fix.smem_start,
                fbi->fb.fix.smem_start + fbi->fb.fix.smem_len - 1);

        return 0;
}

static void wm8505fb_remove(struct platform_device *pdev)
{
        struct wm8505fb_info *fbi = platform_get_drvdata(pdev);

        unregister_framebuffer(&fbi->fb);

        writel(0, fbi->regbase);

        if (fbi->fb.cmap.len)
                fb_dealloc_cmap(&fbi->fb.cmap);
}

static const struct of_device_id wmt_dt_ids[] = {
        { .compatible = "wm,wm8505-fb", },
        {}
};

static struct platform_driver wm8505fb_driver = {
        .probe          = wm8505fb_probe,
        .remove         = wm8505fb_remove,
        .driver         = {
                .name   = DRIVER_NAME,
                .of_match_table = wmt_dt_ids,
                .dev_groups     = wm8505fb_groups,
        },
};

module_platform_driver(wm8505fb_driver);

MODULE_AUTHOR("Ed Spiridonov <edo.rus@gmail.com>");
MODULE_DESCRIPTION("Framebuffer driver for WMT WM8505");
MODULE_DEVICE_TABLE(of, wmt_dt_ids);