[PATCH] video: stm32: ltdc: add .of_to_plat callback
Patrice CHOTARD
patrice.chotard at foss.st.com
Thu Jan 29 11:31:32 CET 2026
On 12/16/25 18:08, Patrice CHOTARD wrote:
>
>
> On 12/9/25 13:19, Raphael Gallais-Pou wrote:
>> Drivers should extract device-tree data before probing via the
>> .of_to_plat hook.
>>
>> Implement it for stm32_ltdc driver. No functional change.
>>
>> Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou at foss.st.com>
>> ---
>> This patch has been tested on stm32mp135f-dk and stm32mp257f-ev1.
>> ---
>> drivers/video/stm32/stm32_ltdc.c | 218 +++++++++++++++++++++------------------
>> 1 file changed, 117 insertions(+), 101 deletions(-)
>>
>> diff --git a/drivers/video/stm32/stm32_ltdc.c b/drivers/video/stm32/stm32_ltdc.c
>> index 834bfb625d2d34a44bd8edff1c92af6dec344c20..1c55fc94b3aa67dbcb822684c2c9a128b159e8a6 100644
>> --- a/drivers/video/stm32/stm32_ltdc.c
>> +++ b/drivers/video/stm32/stm32_ltdc.c
>> @@ -22,8 +22,17 @@
>> #include <linux/bitops.h>
>> #include <linux/printk.h>
>>
>> -struct stm32_ltdc_priv {
>> +struct stm32_ltdc_plat {
>> void __iomem *regs;
>> + struct udevice *bridge;
>> + struct udevice *panel;
>> + struct reset_ctl rst;
>> + struct clk pclk;
>> + struct clk bclk;
>> +};
>> +
>> +struct stm32_ltdc_priv {
>> + struct display_timing timings;
>> enum video_log2_bpp l2bpp;
>> u32 bg_col_argb;
>> const u32 *layer_regs;
>> @@ -364,18 +373,20 @@ static bool has_alpha(u32 fmt)
>> }
>> }
>>
>> -static void stm32_ltdc_enable(struct stm32_ltdc_priv *priv)
>> +static void stm32_ltdc_enable(void __iomem *regs)
>> {
>> /* Reload configuration immediately & enable LTDC */
>> - setbits_le32(priv->regs + LTDC_SRCR, SRCR_IMR);
>> - setbits_le32(priv->regs + LTDC_GCR, GCR_LTDCEN);
>> + setbits_le32(regs + LTDC_SRCR, SRCR_IMR);
>> + setbits_le32(regs + LTDC_GCR, GCR_LTDCEN);
>> }
>>
>> -static void stm32_ltdc_set_mode(struct stm32_ltdc_priv *priv,
>> - struct display_timing *timings)
>> +static void stm32_ltdc_set_mode(struct udevice *dev)
>> {
>> - void __iomem *regs = priv->regs;
>> + struct stm32_ltdc_plat *plat = dev_get_plat(dev);
>> + struct stm32_ltdc_priv *priv = dev_get_priv(dev);
>> + struct display_timing *timings = &priv->timings;
>> u32 hsync, vsync, acc_hbp, acc_vbp, acc_act_w, acc_act_h;
>> + void __iomem *regs = plat->regs;
>> u32 total_w, total_h;
>> u32 val;
>>
>> @@ -422,12 +433,14 @@ static void stm32_ltdc_set_mode(struct stm32_ltdc_priv *priv,
>> GCR_HSPOL | GCR_VSPOL | GCR_DEPOL | GCR_PCPOL, val);
>>
>> /* Overall background color */
>> - writel(priv->bg_col_argb, priv->regs + LTDC_BCCR);
>> + writel(priv->bg_col_argb, regs + LTDC_BCCR);
>> }
>>
>> -static void stm32_ltdc_set_layer1(struct stm32_ltdc_priv *priv, ulong fb_addr)
>> +static void stm32_ltdc_set_layer1(struct udevice *dev, ulong fb_addr)
>> {
>> - void __iomem *regs = priv->regs;
>> + struct stm32_ltdc_plat *plat = dev_get_plat(dev);
>> + struct stm32_ltdc_priv *priv = dev_get_priv(dev);
>> + void __iomem *regs = plat->regs;
>> u32 x0, x1, y0, y1;
>> u32 pitch_in_bytes;
>> u32 line_length;
>> @@ -493,7 +506,7 @@ static void stm32_ltdc_set_layer1(struct stm32_ltdc_priv *priv, ulong fb_addr)
>> writel(fb_addr, regs + LTDC_L1CFBAR);
>>
>> /* Enable layer 1 */
>> - setbits_le32(priv->regs + LTDC_L1CR, LXCR_LEN);
>> + setbits_le32(regs + LTDC_L1CR, LXCR_LEN);
>> }
>>
>> static int stm32_ltdc_get_remote_device(struct udevice *dev, ofnode ep_node,
>> @@ -618,53 +631,99 @@ static inline int stm32_ltdc_alloc_fb(struct udevice *dev)
>> }
>> #endif
>>
>> -static int stm32_ltdc_probe(struct udevice *dev)
>> +static int stm32_ltdc_of_to_plat(struct udevice *dev)
>> {
>> - struct video_uc_plat *uc_plat = dev_get_uclass_plat(dev);
>> - struct video_priv *uc_priv = dev_get_uclass_priv(dev);
>> + struct stm32_ltdc_plat *plat = dev_get_plat(dev);
>> struct stm32_ltdc_priv *priv = dev_get_priv(dev);
>> - struct udevice *bridge = NULL;
>> - struct udevice *panel = NULL;
>> - struct display_timing timings;
>> - struct clk pclk, bclk;
>> - struct reset_ctl rst;
>> ofnode node, port;
>> - ulong rate;
>> int ret;
>>
>> - priv->regs = dev_read_addr_ptr(dev);
>> - if (!priv->regs) {
>> + plat->regs = dev_read_addr_ptr(dev);
>> + if (!plat->regs) {
>> dev_err(dev, "ltdc dt register address error\n");
>> return -EINVAL;
>> }
>>
>> - ret = clk_get_by_name(dev, "bus", &bclk);
>> - if (ret) {
>> - if (ret != -ENODATA) {
>> - dev_err(dev, "bus clock get error %d\n", ret);
>> - return ret;
>> - }
>> - } else {
>> - ret = clk_enable(&bclk);
>> - if (ret) {
>> - dev_err(dev, "bus clock enable error %d\n", ret);
>> - return ret;
>> - }
>> + ret = clk_get_by_name(dev, "bus", &plat->bclk);
>> + if (ret && ret != -ENODATA) {
>> + dev_err(dev, "bus clock get error %d\n", ret);
>> + return ret;
>> }
>>
>> - ret = clk_get_by_name(dev, "lcd", &pclk);
>> + ret = clk_get_by_name(dev, "lcd", &plat->pclk);
>> if (ret) {
>> dev_err(dev, "peripheral clock get error %d\n", ret);
>> return ret;
>> }
>>
>> - ret = clk_enable(&pclk);
>> + /*
>> + * Try all the ports until one working.
>> + *
>> + * This is done in two times. First is checks for the
>> + * UCLASS_VIDEO_BRIDGE available, and then for this bridge
>> + * it scans for a UCLASS_PANEL.
>> + */
>> + port = dev_read_subnode(dev, "port");
>> + if (!ofnode_valid(port)) {
>> + dev_err(dev, "%s(%s): 'port' subnode not found\n",
>> + __func__, dev_read_name(dev));
>> + return -EINVAL;
>> + }
>> +
>> + for (node = ofnode_first_subnode(port);
>> + ofnode_valid(node);
>> + node = dev_read_next_subnode(node)) {
>> + ret = stm32_ltdc_display_init(dev, &node, &plat->panel, &plat->bridge);
>> + if (ret)
>> + dev_dbg(dev, "Device failed ret=%d\n", ret);
>> + else
>> + break;
>> + }
>> +
>> + /* Sanity check */
>> + if (ret)
>> + return ret;
>> +
>> + ret = panel_get_display_timing(plat->panel, &priv->timings);
>> + if (ret) {
>> + ret = ofnode_decode_display_timing(dev_ofnode(plat->panel),
>> + 0, &priv->timings);
>> + if (ret) {
>> + dev_err(dev, "decode display timing error %d\n", ret);
>> + return ret;
>> + }
>> + }
>> +
>> + ret = reset_get_by_index(dev, 0, &plat->rst);
>> + if (ret)
>> + dev_err(dev, "missing ltdc hardware reset\n");
>> +
>> + return ret;
>> +}
>> +
>> +static int stm32_ltdc_probe(struct udevice *dev)
>> +{
>> + struct video_uc_plat *uc_plat = dev_get_uclass_plat(dev);
>> + struct video_priv *uc_priv = dev_get_uclass_priv(dev);
>> + struct stm32_ltdc_plat *plat = dev_get_plat(dev);
>> + struct stm32_ltdc_priv *priv = dev_get_priv(dev);
>> + struct display_timing *timings = &priv->timings;
>> + ulong rate;
>> + int ret;
>> +
>> + ret = clk_enable(&plat->bclk);
>> + if (ret) {
>> + dev_err(dev, "bus clock enable error %d\n", ret);
>> + return ret;
>> + }
>> +
>> + ret = clk_enable(&plat->pclk);
>> if (ret) {
>> dev_err(dev, "peripheral clock enable error %d\n", ret);
>> return ret;
>> }
>>
>> - priv->hw_version = readl(priv->regs + LTDC_IDR);
>> + priv->hw_version = readl(plat->regs + LTDC_IDR);
>> dev_dbg(dev, "%s: LTDC hardware 0x%x\n", __func__, priv->hw_version);
>>
>> switch (priv->hw_version) {
>> @@ -686,67 +745,22 @@ static int stm32_ltdc_probe(struct udevice *dev)
>> return -ENODEV;
>> }
>>
>> - /*
>> - * Try all the ports until one working.
>> - *
>> - * This is done in two times. First is checks for the
>> - * UCLASS_VIDEO_BRIDGE available, and then for this bridge
>> - * it scans for a UCLASS_PANEL.
>> - */
>> -
>> - port = dev_read_subnode(dev, "port");
>> - if (!ofnode_valid(port)) {
>> - dev_err(dev, "%s(%s): 'port' subnode not found\n",
>> - __func__, dev_read_name(dev));
>> - return -EINVAL;
>> - }
>> -
>> - for (node = ofnode_first_subnode(port);
>> - ofnode_valid(node);
>> - node = dev_read_next_subnode(node)) {
>> - ret = stm32_ltdc_display_init(dev, &node, &panel, &bridge);
>> - if (ret)
>> - dev_dbg(dev, "Device failed ret=%d\n", ret);
>> - else
>> - break;
>> - }
>> -
>> - /* Sanity check */
>> - if (ret)
>> - return ret;
>> -
>> - ret = panel_get_display_timing(panel, &timings);
>> - if (ret) {
>> - ret = ofnode_decode_display_timing(dev_ofnode(panel),
>> - 0, &timings);
>> - if (ret) {
>> - dev_err(dev, "decode display timing error %d\n", ret);
>> - return ret;
>> - }
>> - }
>> -
>> - rate = clk_set_rate(&pclk, timings.pixelclock.typ);
>> + rate = clk_set_rate(&plat->pclk, timings->pixelclock.typ);
>> if (IS_ERR_VALUE(rate))
>> dev_warn(dev, "fail to set pixel clock %d hz, ret=%ld\n",
>> - timings.pixelclock.typ, rate);
>> + timings->pixelclock.typ, rate);
>>
>> dev_dbg(dev, "Set pixel clock req %d hz get %ld hz\n",
>> - timings.pixelclock.typ, rate);
>> -
>> - ret = reset_get_by_index(dev, 0, &rst);
>> - if (ret) {
>> - dev_err(dev, "missing ltdc hardware reset\n");
>> - return ret;
>> - }
>> + timings->pixelclock.typ, rate);
>>
>> /* Reset */
>> - reset_deassert(&rst);
>> + reset_deassert(&plat->rst);
>>
>> if (IS_ENABLED(CONFIG_VIDEO_BRIDGE)) {
>> - if (bridge) {
>> - ret = video_bridge_attach(bridge);
>> + if (plat->bridge) {
>> + ret = video_bridge_attach(plat->bridge);
>> if (ret) {
>> - dev_err(bridge, "fail to attach bridge\n");
>> + dev_err(plat->bridge, "fail to attach bridge\n");
>> return ret;
>> }
>> }
>> @@ -757,8 +771,8 @@ static int stm32_ltdc_probe(struct udevice *dev)
>> priv->bg_col_argb = 0xFFFFFFFF; /* white no transparency */
>> priv->crop_x = 0;
>> priv->crop_y = 0;
>> - priv->crop_w = timings.hactive.typ;
>> - priv->crop_h = timings.vactive.typ;
>> + priv->crop_w = timings->hactive.typ;
>> + priv->crop_h = timings->vactive.typ;
>> priv->alpha = 0xFF;
>>
>> ret = stm32_ltdc_alloc_fb(dev);
>> @@ -766,30 +780,30 @@ static int stm32_ltdc_probe(struct udevice *dev)
>> return ret;
>>
>> dev_dbg(dev, "%dx%d %dbpp frame buffer at 0x%lx\n",
>> - timings.hactive.typ, timings.vactive.typ,
>> + timings->hactive.typ, timings->vactive.typ,
>> VNBITS(priv->l2bpp), uc_plat->base);
>> dev_dbg(dev, "crop %d,%d %dx%d bg 0x%08x alpha %d\n",
>> priv->crop_x, priv->crop_y, priv->crop_w, priv->crop_h,
>> priv->bg_col_argb, priv->alpha);
>>
>> /* Configure & start LTDC */
>> - stm32_ltdc_set_mode(priv, &timings);
>> - stm32_ltdc_set_layer1(priv, uc_plat->base);
>> - stm32_ltdc_enable(priv);
>> + stm32_ltdc_set_mode(dev);
>> + stm32_ltdc_set_layer1(dev, uc_plat->base);
>> + stm32_ltdc_enable(plat->regs);
>>
>> - uc_priv->xsize = timings.hactive.typ;
>> - uc_priv->ysize = timings.vactive.typ;
>> + uc_priv->xsize = timings->hactive.typ;
>> + uc_priv->ysize = timings->vactive.typ;
>> uc_priv->bpix = priv->l2bpp;
>>
>> - if (!bridge) {
>> - ret = panel_enable_backlight(panel);
>> + if (!plat->bridge) {
>> + ret = panel_enable_backlight(plat->panel);
>> if (ret) {
>> dev_err(dev, "panel %s enable backlight error %d\n",
>> - panel->name, ret);
>> + plat->panel->name, ret);
>> return ret;
>> }
>> } else if (IS_ENABLED(CONFIG_VIDEO_BRIDGE)) {
>> - ret = video_bridge_set_backlight(bridge, 80);
>> + ret = video_bridge_set_backlight(plat->bridge, 80);
>> if (ret) {
>> dev_err(dev, "fail to set backlight\n");
>> return ret;
>> @@ -827,7 +841,9 @@ U_BOOT_DRIVER(stm32_ltdc) = {
>> .name = "stm32_display",
>> .id = UCLASS_VIDEO,
>> .of_match = stm32_ltdc_ids,
>> + .of_to_plat = stm32_ltdc_of_to_plat,
>> .probe = stm32_ltdc_probe,
>> .bind = stm32_ltdc_bind,
>> + .plat_auto = sizeof(struct stm32_ltdc_plat),
>> .priv_auto = sizeof(struct stm32_ltdc_priv),
>> };
>>
>> ---
>> base-commit: c98b6a6dcd1fc7bcba081fc2353954e33de5053c
>> change-id: 20251209-ltdc-48abd0de6852
>>
>> Best regards,
>
> Hi Raphael
>
> Reviewed-by: Patrice Chotard <patrice.chotard at foss.st.com>
>
> Thanks
> Patrice
>
Applied to u-boot-stm32/master
Thanks
Patrice
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