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Subject[PATCH] video: mxsfb: fix broken video mode selection
Date
currently the driver re-implements the code found in
of_get_videomode() except for the fact that the latter honors the
'native-mode' property to select a spcific video timing from the list
of possible timings. The driver builds up a list of all video timings,
but uses only the last mode from the list anyway. While building the
list it incorrectly OR's the 'pixelclk-active' and 'de-active' flags
of all modes into single flags, possibly leading to a wrong pixelclock
or data-enable polarity setting.

Fix this by using the of_get_videomode() directly with the
OF_USE_NATIVE_MODE flag.

Since all current dts files only have one entry in their
display-timings node, this bug was not apparent and the fix does not
change the driver's behaviour for the current users.

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
---
drivers/video/mxsfb.c | 126 ++++++++++++++++++++----------------------------
1 files changed, 53 insertions(+), 73 deletions(-)

diff --git a/drivers/video/mxsfb.c b/drivers/video/mxsfb.c
index 27197a8..accf48a2 100644
--- a/drivers/video/mxsfb.c
+++ b/drivers/video/mxsfb.c
@@ -49,6 +49,7 @@
#include <linux/fb.h>
#include <linux/regulator/consumer.h>
#include <video/of_display_timing.h>
+#include <video/of_videomode.h>
#include <video/videomode.h>

#define REG_SET 4
@@ -297,7 +298,7 @@ static int mxsfb_check_var(struct fb_var_screeninfo *var,
}
break;
default:
- pr_debug("Unsupported colour depth: %u\n", var->bits_per_pixel);
+ pr_err("Unsupported colour depth: %u\n", var->bits_per_pixel);
return -EINVAL;
}

@@ -426,7 +427,7 @@ static int mxsfb_set_par(struct fb_info *fb_info)
ctrl |= CTRL_SET_WORD_LENGTH(3);
switch (host->ld_intf_width) {
case STMLCDIF_8BIT:
- dev_dbg(&host->pdev->dev,
+ dev_err(&host->pdev->dev,
"Unsupported LCD bus width mapping\n");
return -EINVAL;
case STMLCDIF_16BIT:
@@ -439,7 +440,7 @@ static int mxsfb_set_par(struct fb_info *fb_info)
writel(CTRL1_SET_BYTE_PACKAGING(0x7), host->base + LCDC_CTRL1);
break;
default:
- dev_dbg(&host->pdev->dev, "Unhandled color depth of %u\n",
+ dev_err(&host->pdev->dev, "Unhandled color depth of %u\n",
fb_info->var.bits_per_pixel);
return -EINVAL;
}
@@ -589,7 +590,8 @@ static struct fb_ops mxsfb_ops = {
.fb_imageblit = cfb_imageblit,
};

-static int mxsfb_restore_mode(struct mxsfb_info *host)
+static int mxsfb_restore_mode(struct mxsfb_info *host,
+ struct fb_videomode *vmode)
{
struct fb_info *fb_info = &host->fb_info;
unsigned line_count;
@@ -597,7 +599,6 @@ static int mxsfb_restore_mode(struct mxsfb_info *host)
unsigned long pa, fbsize;
int bits_per_pixel, ofs;
u32 transfer_count, vdctrl0, vdctrl2, vdctrl3, vdctrl4, ctrl;
- struct fb_videomode vmode;

/* Only restore the mode when the controller is running */
ctrl = readl(host->base + LCDC_CTRL);
@@ -611,8 +612,8 @@ static int mxsfb_restore_mode(struct mxsfb_info *host)

transfer_count = readl(host->base + host->devdata->transfer_count);

- vmode.xres = TRANSFER_COUNT_GET_HCOUNT(transfer_count);
- vmode.yres = TRANSFER_COUNT_GET_VCOUNT(transfer_count);
+ vmode->xres = TRANSFER_COUNT_GET_HCOUNT(transfer_count);
+ vmode->yres = TRANSFER_COUNT_GET_VCOUNT(transfer_count);

switch (CTRL_GET_WORD_LENGTH(ctrl)) {
case 0:
@@ -628,40 +629,39 @@ static int mxsfb_restore_mode(struct mxsfb_info *host)

fb_info->var.bits_per_pixel = bits_per_pixel;

- vmode.pixclock = KHZ2PICOS(clk_get_rate(host->clk) / 1000U);
- vmode.hsync_len = get_hsync_pulse_width(host, vdctrl2);
- vmode.left_margin = GET_HOR_WAIT_CNT(vdctrl3) - vmode.hsync_len;
- vmode.right_margin = VDCTRL2_GET_HSYNC_PERIOD(vdctrl2) - vmode.hsync_len -
- vmode.left_margin - vmode.xres;
- vmode.vsync_len = VDCTRL0_GET_VSYNC_PULSE_WIDTH(vdctrl0);
+ vmode->pixclock = KHZ2PICOS(clk_get_rate(host->clk) / 1000U);
+ vmode->hsync_len = get_hsync_pulse_width(host, vdctrl2);
+ vmode->left_margin = GET_HOR_WAIT_CNT(vdctrl3) - vmode->hsync_len;
+ vmode->right_margin = VDCTRL2_GET_HSYNC_PERIOD(vdctrl2) -
+ vmode->hsync_len - vmode->left_margin - vmode->xres;
+ vmode->vsync_len = VDCTRL0_GET_VSYNC_PULSE_WIDTH(vdctrl0);
period = readl(host->base + LCDC_VDCTRL1);
- vmode.upper_margin = GET_VERT_WAIT_CNT(vdctrl3) - vmode.vsync_len;
- vmode.lower_margin = period - vmode.vsync_len - vmode.upper_margin - vmode.yres;
+ vmode->upper_margin = GET_VERT_WAIT_CNT(vdctrl3) - vmode->vsync_len;
+ vmode->lower_margin = period - vmode->vsync_len -
+ vmode->upper_margin - vmode->yres;

- vmode.vmode = FB_VMODE_NONINTERLACED;
+ vmode->vmode = FB_VMODE_NONINTERLACED;

- vmode.sync = 0;
+ vmode->sync = 0;
if (vdctrl0 & VDCTRL0_HSYNC_ACT_HIGH)
- vmode.sync |= FB_SYNC_HOR_HIGH_ACT;
+ vmode->sync |= FB_SYNC_HOR_HIGH_ACT;
if (vdctrl0 & VDCTRL0_VSYNC_ACT_HIGH)
- vmode.sync |= FB_SYNC_VERT_HIGH_ACT;
+ vmode->sync |= FB_SYNC_VERT_HIGH_ACT;

pr_debug("Reconstructed video mode:\n");
pr_debug("%dx%d, hsync: %u left: %u, right: %u, vsync: %u, upper: %u, lower: %u\n",
- vmode.xres, vmode.yres,
- vmode.hsync_len, vmode.left_margin, vmode.right_margin,
- vmode.vsync_len, vmode.upper_margin, vmode.lower_margin);
- pr_debug("pixclk: %ldkHz\n", PICOS2KHZ(vmode.pixclock));
-
- fb_add_videomode(&vmode, &fb_info->modelist);
+ vmode->xres, vmode->yres, vmode->hsync_len, vmode->left_margin,
+ vmode->right_margin, vmode->vsync_len, vmode->upper_margin,
+ vmode->lower_margin);
+ pr_debug("pixclk: %ldkHz\n", PICOS2KHZ(vmode->pixclock));

host->ld_intf_width = CTRL_GET_BUS_WIDTH(ctrl);
host->dotclk_delay = VDCTRL4_GET_DOTCLK_DLY(vdctrl4);

- fb_info->fix.line_length = vmode.xres * (bits_per_pixel >> 3);
+ fb_info->fix.line_length = vmode->xres * (bits_per_pixel >> 3);

pa = readl(host->base + host->devdata->cur_buf);
- fbsize = fb_info->fix.line_length * vmode.yres;
+ fbsize = fb_info->fix.line_length * vmode->yres;
if (pa < fb_info->fix.smem_start)
return -EINVAL;
if (pa + fbsize > fb_info->fix.smem_start + fb_info->fix.smem_len)
@@ -681,18 +681,17 @@ static int mxsfb_restore_mode(struct mxsfb_info *host)
return 0;
}

-static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host)
+static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host,
+ struct fb_videomode *vmode)
{
struct fb_info *fb_info = &host->fb_info;
struct fb_var_screeninfo *var = &fb_info->var;
struct device *dev = &host->pdev->dev;
struct device_node *np = host->pdev->dev.of_node;
struct device_node *display_np;
- struct device_node *timings_np;
- struct display_timings *timings;
+ struct videomode vm;
u32 width;
- int i;
- int ret = 0;
+ int ret;

display_np = of_parse_phandle(np, "display", 0);
if (!display_np) {
@@ -732,54 +731,35 @@ static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host)
goto put_display_node;
}

- timings = of_get_display_timings(display_np);
- if (!timings) {
- dev_err(dev, "failed to get display timings\n");
- ret = -ENOENT;
+ ret = of_get_videomode(display_np, &vm, OF_USE_NATIVE_MODE);
+ if (ret) {
+ dev_err(dev, "failed to get videomode from DT\n");
goto put_display_node;
}

- timings_np = of_find_node_by_name(display_np,
- "display-timings");
- if (!timings_np) {
- dev_err(dev, "failed to find display-timings node\n");
- ret = -ENOENT;
+ ret = fb_videomode_from_videomode(&vm, vmode);
+ if (ret < 0)
goto put_display_node;
- }

- for (i = 0; i < of_get_child_count(timings_np); i++) {
- struct videomode vm;
- struct fb_videomode fb_vm;
-
- ret = videomode_from_timings(timings, &vm, i);
- if (ret < 0)
- goto put_timings_node;
- ret = fb_videomode_from_videomode(&vm, &fb_vm);
- if (ret < 0)
- goto put_timings_node;
-
- if (vm.flags & DISPLAY_FLAGS_DE_HIGH)
- host->sync |= MXSFB_SYNC_DATA_ENABLE_HIGH_ACT;
- if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE)
- host->sync |= MXSFB_SYNC_DOTCLK_FALLING_ACT;
- fb_add_videomode(&fb_vm, &fb_info->modelist);
- }
+ if (vm.flags & DISPLAY_FLAGS_DE_HIGH)
+ host->sync |= MXSFB_SYNC_DATA_ENABLE_HIGH_ACT;
+ if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE)
+ host->sync |= MXSFB_SYNC_DOTCLK_FALLING_ACT;

-put_timings_node:
- of_node_put(timings_np);
put_display_node:
of_node_put(display_np);
return ret;
}

-static int mxsfb_init_fbinfo(struct mxsfb_info *host)
+static int mxsfb_init_fbinfo(struct mxsfb_info *host,
+ struct fb_videomode *vmode)
{
+ int ret;
struct fb_info *fb_info = &host->fb_info;
struct fb_var_screeninfo *var = &fb_info->var;
dma_addr_t fb_phys;
void *fb_virt;
unsigned fb_size;
- int ret;

fb_info->fbops = &mxsfb_ops;
fb_info->flags = FBINFO_FLAG_DEFAULT | FBINFO_READS_FAST;
@@ -789,7 +769,7 @@ static int mxsfb_init_fbinfo(struct mxsfb_info *host)
fb_info->fix.visual = FB_VISUAL_TRUECOLOR,
fb_info->fix.accel = FB_ACCEL_NONE;

- ret = mxsfb_init_fbinfo_dt(host);
+ ret = mxsfb_init_fbinfo_dt(host, vmode);
if (ret)
return ret;

@@ -810,7 +790,7 @@ static int mxsfb_init_fbinfo(struct mxsfb_info *host)
fb_info->screen_base = fb_virt;
fb_info->screen_size = fb_info->fix.smem_len = fb_size;

- if (mxsfb_restore_mode(host))
+ if (mxsfb_restore_mode(host, vmode))
memset(fb_virt, 0, fb_size);

return 0;
@@ -850,7 +830,7 @@ static int mxsfb_probe(struct platform_device *pdev)
struct resource *res;
struct mxsfb_info *host;
struct fb_info *fb_info;
- struct fb_modelist *modelist;
+ struct fb_videomode *mode;
int ret;

if (of_id)
@@ -862,6 +842,11 @@ static int mxsfb_probe(struct platform_device *pdev)
return -ENOMEM;
}

+ mode = devm_kzalloc(&pdev->dev, sizeof(struct fb_videomode),
+ GFP_KERNEL);
+ if (mode == NULL)
+ return -ENOMEM;
+
host = to_imxfb_host(fb_info);

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -893,15 +878,11 @@ static int mxsfb_probe(struct platform_device *pdev)
goto fb_release;
}

- INIT_LIST_HEAD(&fb_info->modelist);
-
- ret = mxsfb_init_fbinfo(host);
+ ret = mxsfb_init_fbinfo(host, mode);
if (ret != 0)
goto fb_release;

- modelist = list_first_entry(&fb_info->modelist,
- struct fb_modelist, list);
- fb_videomode_to_var(&fb_info->var, &modelist->mode);
+ fb_videomode_to_var(&fb_info->var, mode);

/* init the color fields */
mxsfb_check_var(&fb_info->var, fb_info);
@@ -927,7 +908,6 @@ static int mxsfb_probe(struct platform_device *pdev)
fb_destroy:
if (host->enabled)
clk_disable_unprepare(host->clk);
- fb_destroy_modelist(&fb_info->modelist);
fb_release:
framebuffer_release(fb_info);

--
1.7.2.5
--
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