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

[Pawel Moll]

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@xxxxxxx>
---
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@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@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

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