[PATCH v9] video: ARM CLCD: Add DT support

Pawel Moll
2014-06-24T11:55:11Z

This patch adds basic DT bindings for the PL11x CLCD cells
and make their fbdev driver use them.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
---
Changes since v8:
- removed "arm,pl11x,framebuffer" property; a "memory-region"
phandle is to be used instead

Changes since v7:
- fixed typo in "clock-names" documentation
- renamed "arm,pl11x,framebuffer-base" into "arm,pl11x,framebuffer"
as it is describing both base and size
- added more explanation for "max-memory-bandwidth" property
- added more explanation for "arm,pl11x,tft-r0g0b0" property

Changes since v6:
- replaced in-node device-timing subnode with the standard
video interface bindings (as in: ports & endpoints); only
"panel-dpi" compatible panels are supported in the driver

Changes since v5:
- realised that dma_alloc_writecombine() is a arm-specific function;
replaced with generic dma_alloc_coherent()/dma_mmap_writecombine()

Changes since v4:
- simplified the pads description property and made it optional

Changes since v3:
- changed wording and order of interrupt-names and interrupts
properties documentation
- changed wording of arm,pl11x,framebuffer-base property
documentation
- cleaned up binding documentation indentation

Changes since v2:
- replaced video-ram phandle with arm,pl11x,framebuffer-base
- replaced panel-* properties with arm,pl11x,panel-data-pads
- replaced max-framebuffer-size with max-memory-bandwidth
- modified clcdfb_of_init_tft_panel() to use the pads
data and take differences between PL110 and PL110 into
account

Changes since v1:
- minor code cleanups as suggested by Sylwester Nawrocki

.../devicetree/bindings/video/arm,pl11x.txt | 109 +++++++++
drivers/video/fbdev/Kconfig | 1 +
drivers/video/fbdev/amba-clcd.c | 263 +++++++++++++++++++++
3 files changed, 373 insertions(+)
create mode 100644 Documentation/devicetree/bindings/video/arm,pl11x.txt

diff --git a/Documentation/devicetree/bindings/video/arm,pl11x.txt b/Documentation/devicetree/bindings/video/arm,pl11x.txt
new file mode 100644
index 0000000..3e3039a
--- /dev/null
+++ b/Documentation/devicetree/bindings/video/arm,pl11x.txt
@@ -0,0 +1,109 @@
+* ARM PrimeCell Color LCD Controller PL110/PL111
+
+See also Documentation/devicetree/bindings/arm/primecell.txt
+
+Required properties:
+
+- compatible: must be one of:
+ "arm,pl110", "arm,primecell"
+ "arm,pl111", "arm,primecell"
+
+- reg: base address and size of the control registers block
+
+- interrupt-names: either the single entry "combined" representing a
+ combined interrupt output (CLCDINTR), or the four entries
+ "mbe", "vcomp", "lnbu", "fuf" representing the individual
+ CLCDMBEINTR, CLCDVCOMPINTR, CLCDLNBUINTR, CLCDFUFINTR interrupts
+
+- interrupts: contains an interrupt specifier for each entry in
+ interrupt-names
+
+- clock-names: should contain "clcdclk" and "apb_pclk"
+
+- clocks: contains phandle and clock specifier pairs for the entries
+ in the clock-names property. See
+ Documentation/devicetree/binding/clock/clock-bindings.txt
+
+Optional properties:
+
+- memory-region: phandle to a node describing memory (see
+ Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt)
+ to be used for the framebuffer; if not present, the framebuffer
+ may be located anywhere in the memory
+
+- max-memory-bandwidth: maximum bandwidth in bytes per second that the
+ cell's memory interface can handle; if not present, the memory
+ interface is fast enough to handle all possible video modes
+
+Required sub-nodes:
+
+- port: describes LCD panel signals, following the common binding
+ for video transmitter interfaces; see
+ Documentation/devicetree/bindings/media/video-interfaces.txt;
+ when it is a TFT panel, the port's endpoint must define the
+ following property:
+
+ - arm,pl11x,tft-r0g0b0-pads: an array of three 32-bit values,
+ defining the way CLD pads are wired up; first value
+ contains index of the "CLD" external pin (pad) used
+ as R0 (first bit of the red component), second value
+ index of the pad used as G0, third value index of the
+ pad used as B0, see also "LCD panel signal multiplexing
+ details" paragraphs in the PL110/PL111 Technical
+ Reference Manuals; this implicitly defines available
+ color modes, for example:
+ - PL111 TFT 4:4:4 panel:
+ arm,pl11x,tft-r0g0b0-pads = <4 15 20>;
+ - PL110 TFT (1:)5:5:5 panel:
+ arm,pl11x,tft-r0g0b0-pads = <1 7 13>;
+ - PL111 TFT (1:)5:5:5 panel:
+ arm,pl11x,tft-r0g0b0-pads = <3 11 19>;
+ - PL111 TFT 5:6:5 panel:
+ arm,pl11x,tft-r0g0b0-pads = <3 10 19>;
+ - PL110 and PL111 TFT 8:8:8 panel:
+ arm,pl11x,tft-r0g0b0-pads = <0 8 16>;
+ - PL110 and PL111 TFT 8:8:8 panel, R & B components swapped:
+ arm,pl11x,tft-r0g0b0-pads = <16 8 0>;
+
+
+Example:
+
+ clcd at 10020000 {
+ compatible = "arm,pl111", "arm,primecell";
+ reg = <0x10020000 0x1000>;
+ interrupt-names = "combined";
+ interrupts = <0 44 4>;
+ clocks = <&oscclk1>, <&oscclk2>;
+ clock-names = "clcdclk", "apb_pclk";
+ max-memory-bandwidth = <94371840>; /* Bps, 1024x768 at 60 16bpp */
+
+ port {
+ clcd_pads: endpoint {
+ remote-endpoint = <&clcd_panel>;
+ arm,pl11x,tft-r0g0b0-pads = <0 8 16>;
+ };
+ };
+
+ };
+
+ panel {
+ compatible = "panel-dpi";
+
+ port {
+ clcd_panel: endpoint {
+ remote-endpoint = <&clcd_pads>;
+ };
+ };
+
+ panel-timing {
+ clock-frequency = <25175000>;
+ hactive = <640>;
+ hback-porch = <40>;
+ hfront-porch = <24>;
+ hsync-len = <96>;
+ vactive = <480>;
+ vback-porch = <32>;
+ vfront-porch = <11>;
+ vsync-len = <2>;
+ };
+ };
diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig
index 59c98bfd..a518fe5 100644
--- a/drivers/video/fbdev/Kconfig
+++ b/drivers/video/fbdev/Kconfig
@@ -280,6 +280,7 @@ config FB_ARMCLCD
select FB_CFB_FILLRECT
select FB_CFB_COPYAREA
select FB_CFB_IMAGEBLIT
+ select VIDEOMODE_HELPERS if OF
help
This framebuffer device driver is for the ARM PrimeCell PL110
Colour LCD controller. ARM PrimeCells provide the building
diff --git a/drivers/video/fbdev/amba-clcd.c b/drivers/video/fbdev/amba-clcd.c
index 14d6b37..23b3519 100644
--- a/drivers/video/fbdev/amba-clcd.c
+++ b/drivers/video/fbdev/amba-clcd.c
@@ -26,6 +26,13 @@
#include <linux/amba/clcd.h>
#include <linux/clk.h>
#include <linux/hardirq.h>
+#include <linux/dma-mapping.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_graph.h>
+#include <video/display_timing.h>
+#include <video/of_display_timing.h>
+#include <video/videomode.h>

#include <asm/sizes.h>

@@ -543,6 +550,259 @@ static int clcdfb_register(struct clcd_fb *fb)
return ret;
}

+#ifdef CONFIG_OF
+static int clcdfb_of_get_dpi_panel_mode(struct device_node *node,
+ struct fb_videomode *mode)
+{
+ int err;
+ struct display_timing timing;
+ struct videomode video;
+
+ err = of_get_display_timing(node, "panel-timing", &timing);
+ if (err)
+ return err;
+
+ videomode_from_timing(&timing, &video);
+
+ err = fb_videomode_from_videomode(&video, mode);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+static int clcdfb_snprintf_mode(char *buf, int size, struct fb_videomode *mode)
+{
+ return snprintf(buf, size, "%ux%u@%u", mode->xres, mode->yres,
+ mode->refresh);
+}
+
+static int clcdfb_of_get_mode(struct device *dev, struct device_node *endpoint,
+ struct fb_videomode *mode)
+{
+ int err;
+ struct device_node *panel;
+ char *name;
+ int len;
+
+ panel = of_graph_get_remote_port_parent(endpoint);
+ if (!panel)
+ return -ENODEV;
+
+ /* Only directly connected DPI panels supported for now */
+ if (of_device_is_compatible(panel, "panel-dpi"))
+ err = clcdfb_of_get_dpi_panel_mode(panel, mode);
+ else
+ err = -ENOENT;
+ if (err)
+ return err;
+
+ len = clcdfb_snprintf_mode(NULL, 0, mode);
+ name = devm_kzalloc(dev, len + 1, GFP_KERNEL);
+ clcdfb_snprintf_mode(name, len + 1, mode);
+ mode->name = name;
+
+ return 0;
+}
+
+static int clcdfb_of_init_tft_panel(struct clcd_fb *fb, u32 r0, u32 g0, u32 b0)
+{
+ static struct {
+ unsigned int part;
+ u32 r0, g0, b0;
+ u32 caps;
+ } panels[] = {
+ { 0x110, 1, 7, 13, CLCD_CAP_5551 },
+ { 0x110, 0, 8, 16, CLCD_CAP_888 },
+ { 0x111, 4, 14, 20, CLCD_CAP_444 },
+ { 0x111, 3, 11, 19, CLCD_CAP_444 | CLCD_CAP_5551 },
+ { 0x111, 3, 10, 19, CLCD_CAP_444 | CLCD_CAP_5551 |
+ CLCD_CAP_565 },
+ { 0x111, 0, 8, 16, CLCD_CAP_444 | CLCD_CAP_5551 |
+ CLCD_CAP_565 | CLCD_CAP_888 },
+ };
+ int i;
+
+ /* Bypass pixel clock divider, data output on the falling edge */
+ fb->panel->tim2 = TIM2_BCD | TIM2_IPC;
+
+ /* TFT display, vert. comp. interrupt at the start of the back porch */
+ fb->panel->cntl |= CNTL_LCDTFT | CNTL_LCDVCOMP(1);
+
+ fb->panel->caps = 0;
+
+ /* Match the setup with known variants */
+ for (i = 0; i < ARRAY_SIZE(panels) && !fb->panel->caps; i++) {
+ if (amba_part(fb->dev) != panels[i].part)
+ continue;
+ if (g0 != panels[i].g0)
+ continue;
+ if (r0 == panels[i].r0 && b0 == panels[i].b0)
+ fb->panel->caps = panels[i].caps & CLCD_CAP_RGB;
+ if (r0 == panels[i].b0 && b0 == panels[i].r0)
+ fb->panel->caps = panels[i].caps & CLCD_CAP_BGR;
+ }
+
+ return fb->panel->caps ? 0 : -EINVAL;
+}
+
+static int clcdfb_of_init_display(struct clcd_fb *fb)
+{
+ struct device_node *endpoint;
+ int err;
+ u32 max_bandwidth;
+ u32 tft_r0b0g0[3];
+
+ fb->panel = devm_kzalloc(&fb->dev->dev, sizeof(*fb->panel), GFP_KERNEL);
+ if (!fb->panel)
+ return -ENOMEM;
+
+ endpoint = of_graph_get_next_endpoint(fb->dev->dev.of_node, NULL);
+ if (!endpoint)
+ return -ENODEV;
+
+ err = clcdfb_of_get_mode(&fb->dev->dev, endpoint, &fb->panel->mode);
+ if (err)
+ return err;
+
+ err = of_property_read_u32(fb->dev->dev.of_node, "max-memory-bandwidth",
+ &max_bandwidth);
+ if (!err)
+ fb->panel->bpp = 8 * max_bandwidth / (fb->panel->mode.xres *
+ fb->panel->mode.yres * fb->panel->mode.refresh);
+ else
+ fb->panel->bpp = 32;
+
+#ifdef CONFIG_CPU_BIG_ENDIAN
+ fb->panel->cntl |= CNTL_BEBO;
+#endif
+ fb->panel->width = -1;
+ fb->panel->height = -1;
+
+ if (of_property_read_u32_array(endpoint,
+ "arm,pl11x,tft-r0g0b0-pads",
+ tft_r0b0g0, ARRAY_SIZE(tft_r0b0g0)) == 0)
+ return clcdfb_of_init_tft_panel(fb, tft_r0b0g0[0],
+ tft_r0b0g0[1], tft_r0b0g0[2]);
+
+ return -ENOENT;
+}
+
+static int clcdfb_of_vram_setup(struct clcd_fb *fb)
+{
+ int err;
+ struct device_node *memory;
+ u64 size;
+
+ err = clcdfb_of_init_display(fb);
+ if (err)
+ return err;
+
+ memory = of_parse_phandle(fb->dev->dev.of_node, "memory-region", 0);
+ if (!memory)
+ return -ENODEV;
+
+ fb->fb.screen_base = of_iomap(memory, 0);
+ if (!fb->fb.screen_base)
+ return -ENOMEM;
+
+ fb->fb.fix.smem_start = of_translate_address(memory,
+ of_get_address(memory, 0, &size, NULL));
+ fb->fb.fix.smem_len = size;
+
+ return 0;
+}
+
+static int clcdfb_of_vram_mmap(struct clcd_fb *fb, struct vm_area_struct *vma)
+{
+ unsigned long off, user_size, kernel_size;
+
+
+ off = vma->vm_pgoff << PAGE_SHIFT;
+ user_size = vma->vm_end - vma->vm_start;
+ kernel_size = fb->fb.fix.smem_len;
+
+ if (off >= kernel_size || user_size > (kernel_size - off))
+ return -ENXIO;
+
+ return remap_pfn_range(vma, vma->vm_start,
+ __phys_to_pfn(fb->fb.fix.smem_start) + vma->vm_pgoff,
+ user_size,
+ pgprot_writecombine(vma->vm_page_prot));
+}
+
+static void clcdfb_of_vram_remove(struct clcd_fb *fb)
+{
+ iounmap(fb->fb.screen_base);
+}
+
+static int clcdfb_of_dma_setup(struct clcd_fb *fb)
+{
+ unsigned long framesize;
+ dma_addr_t dma;
+ int err;
+
+ err = clcdfb_of_init_display(fb);
+ if (err)
+ return err;
+
+ framesize = fb->panel->mode.xres * fb->panel->mode.yres *
+ fb->panel->bpp / 8;
+ fb->fb.screen_base = dma_alloc_coherent(&fb->dev->dev, framesize,
+ &dma, GFP_KERNEL);
+ if (!fb->fb.screen_base)
+ return -ENOMEM;
+
+ fb->fb.fix.smem_start = dma;
+ fb->fb.fix.smem_len = framesize;
+
+ return 0;
+}
+
+static int clcdfb_of_dma_mmap(struct clcd_fb *fb, struct vm_area_struct *vma)
+{
+ return dma_mmap_writecombine(&fb->dev->dev, vma, fb->fb.screen_base,
+ fb->fb.fix.smem_start, fb->fb.fix.smem_len);
+}
+
+static void clcdfb_of_dma_remove(struct clcd_fb *fb)
+{
+ dma_free_coherent(&fb->dev->dev, fb->fb.fix.smem_len,
+ fb->fb.screen_base, fb->fb.fix.smem_start);
+}
+
+static struct clcd_board *clcdfb_of_get_board(struct amba_device *dev)
+{
+ struct clcd_board *board = devm_kzalloc(&dev->dev, sizeof(*board),
+ GFP_KERNEL);
+ struct device_node *node = dev->dev.of_node;
+
+ if (!board)
+ return NULL;
+
+ board->name = of_node_full_name(node);
+ board->caps = CLCD_CAP_ALL;
+ board->check = clcdfb_check;
+ board->decode = clcdfb_decode;
+ if (of_find_property(node, "memory-region", NULL)) {
+ board->setup = clcdfb_of_vram_setup;
+ board->mmap = clcdfb_of_vram_mmap;
+ board->remove = clcdfb_of_vram_remove;
+ } else {
+ board->setup = clcdfb_of_dma_setup;
+ board->mmap = clcdfb_of_dma_mmap;
+ board->remove = clcdfb_of_dma_remove;
+ }
+
+ return board;
+}
+#else
+static struct clcd_board *clcdfb_of_get_board(struct amba_dev *dev)
+{
+ return NULL;
+}
+#endif
+
static int clcdfb_probe(struct amba_device *dev, const struct amba_id *id)
{
struct clcd_board *board = dev_get_platdata(&dev->dev);
@@ -550,6 +810,9 @@ static int clcdfb_probe(struct amba_device *dev, const struct amba_id *id)
int ret;

if (!board)
+ board = clcdfb_of_get_board(dev);
+
+ if (!board)
return -EINVAL;

ret = dma_set_mask_and_coherent(&dev->dev, DMA_BIT_MASK(32));
--
1.9.1