[RFC PATCH 1/3] amba-clcd: Add Device Tree support to amba-clcd driver
Ryan Harkin
ryan.harkin at linaro.org
Fri Sep 21 06:35:30 EDT 2012
Hi Liviu,
Thanks for your feedback. All good stuff...
On 20 September 2012 11:24, Liviu Dudau <Liviu.Dudau at arm.com> wrote:
> On Wed, Sep 19, 2012 at 05:04:24PM +0100, Ryan Harkin wrote:
>> Add support to parse the display configuration from device tree.
>>
>> If the board does not provide platform specific functions in the struct
>> clcd_board contained with the amba device info, then defaults are provided
>> by the driver.
>>
>> The device tree configuration can either ask for a DMA setup or provide a
>> framebuffer address to be remapped into the driver.
>>
>> Signed-off-by: Ryan Harkin <ryan.harkin at linaro.org>
>> ---
>> drivers/video/amba-clcd.c | 253 +++++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 253 insertions(+)
>>
>> diff --git a/drivers/video/amba-clcd.c b/drivers/video/amba-clcd.c
>> index 0a2cce7..01dbad1 100644
>> --- a/drivers/video/amba-clcd.c
>> +++ b/drivers/video/amba-clcd.c
>> @@ -16,7 +16,10 @@
>> #include <linux/string.h>
>> #include <linux/slab.h>
>> #include <linux/delay.h>
>> +#include <linux/dma-mapping.h>
>> +#include <linux/memblock.h>
>> #include <linux/mm.h>
>> +#include <linux/of.h>
>> #include <linux/fb.h>
>> #include <linux/init.h>
>> #include <linux/ioport.h>
>> @@ -391,6 +394,19 @@ static int clcdfb_blank(int blank_mode, struct fb_info *info)
>> }
>> return 0;
>> }
>> +int clcdfb_mmap_dma(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);
>> +}
>> +
>> +void clcdfb_remove_dma(struct clcd_fb *fb)
>> +{
>> + dma_free_writecombine(&fb->dev->dev, fb->fb.fix.smem_len,
>> + fb->fb.screen_base, fb->fb.fix.smem_start);
>> +}
>>
>> static int clcdfb_mmap(struct fb_info *info,
>> struct vm_area_struct *vma)
>> @@ -542,12 +558,249 @@ static int clcdfb_register(struct clcd_fb *fb)
>> return ret;
>> }
>>
>> +struct string_lookup {
>> + const char *string;
>> + const u32 val;
>> +};
>> +
>> +static struct string_lookup vmode_lookups[] = {
>> + { "FB_VMODE_NONINTERLACED", FB_VMODE_NONINTERLACED},
>> + { "FB_VMODE_INTERLACED", FB_VMODE_INTERLACED},
>> + { "FB_VMODE_DOUBLE", FB_VMODE_DOUBLE},
>> + { "FB_VMODE_ODD_FLD_FIRST", FB_VMODE_ODD_FLD_FIRST},
>> + { NULL, 0 },
>> +};
>> +
>> +static struct string_lookup tim2_lookups[] = {
>> + { "TIM2_CLKSEL", TIM2_CLKSEL},
>> + { "TIM2_IVS", TIM2_IVS},
>> + { "TIM2_IHS", TIM2_IHS},
>> + { "TIM2_IPC", TIM2_IPC},
>> + { "TIM2_IOE", TIM2_IOE},
>> + { "TIM2_BCD", TIM2_BCD},
>> + { NULL, 0},
>> +};
>> +static struct string_lookup cntl_lookups[] = {
>> + {"CNTL_LCDEN", CNTL_LCDEN},
>> + {"CNTL_LCDBPP1", CNTL_LCDBPP1},
>> + {"CNTL_LCDBPP2", CNTL_LCDBPP2},
>> + {"CNTL_LCDBPP4", CNTL_LCDBPP4},
>> + {"CNTL_LCDBPP8", CNTL_LCDBPP8},
>> + {"CNTL_LCDBPP16", CNTL_LCDBPP16},
>> + {"CNTL_LCDBPP16_565", CNTL_LCDBPP16_565},
>> + {"CNTL_LCDBPP16_444", CNTL_LCDBPP16_444},
>> + {"CNTL_LCDBPP24", CNTL_LCDBPP24},
>> + {"CNTL_LCDBW", CNTL_LCDBW},
>> + {"CNTL_LCDTFT", CNTL_LCDTFT},
>> + {"CNTL_LCDMONO8", CNTL_LCDMONO8},
>> + {"CNTL_LCDDUAL", CNTL_LCDDUAL},
>> + {"CNTL_BGR", CNTL_BGR},
>> + {"CNTL_BEBO", CNTL_BEBO},
>> + {"CNTL_BEPO", CNTL_BEPO},
>> + {"CNTL_LCDPWR", CNTL_LCDPWR},
>> + {"CNTL_LCDVCOMP(1)", CNTL_LCDVCOMP(1)},
>> + {"CNTL_LCDVCOMP(2)", CNTL_LCDVCOMP(2)},
>> + {"CNTL_LCDVCOMP(3)", CNTL_LCDVCOMP(3)},
>> + {"CNTL_LCDVCOMP(4)", CNTL_LCDVCOMP(4)},
>> + {"CNTL_LCDVCOMP(5)", CNTL_LCDVCOMP(5)},
>> + {"CNTL_LCDVCOMP(6)", CNTL_LCDVCOMP(6)},
>> + {"CNTL_LCDVCOMP(7)", CNTL_LCDVCOMP(7)},
>> + {"CNTL_LDMAFIFOTIME", CNTL_LDMAFIFOTIME},
>> + {"CNTL_WATERMARK", CNTL_WATERMARK},
>> + { NULL, 0},
>> +};
>> +static struct string_lookup caps_lookups[] = {
>> + {"CLCD_CAP_RGB444", CLCD_CAP_RGB444},
>> + {"CLCD_CAP_RGB5551", CLCD_CAP_RGB5551},
>> + {"CLCD_CAP_RGB565", CLCD_CAP_RGB565},
>> + {"CLCD_CAP_RGB888", CLCD_CAP_RGB888},
>> + {"CLCD_CAP_BGR444", CLCD_CAP_BGR444},
>> + {"CLCD_CAP_BGR5551", CLCD_CAP_BGR5551},
>> + {"CLCD_CAP_BGR565", CLCD_CAP_BGR565},
>> + {"CLCD_CAP_BGR888", CLCD_CAP_BGR888},
>> + {"CLCD_CAP_444", CLCD_CAP_444},
>> + {"CLCD_CAP_5551", CLCD_CAP_5551},
>> + {"CLCD_CAP_565", CLCD_CAP_565},
>> + {"CLCD_CAP_888", CLCD_CAP_888},
>> + {"CLCD_CAP_RGB", CLCD_CAP_RGB},
>> + {"CLCD_CAP_BGR", CLCD_CAP_BGR},
>> + {"CLCD_CAP_ALL", CLCD_CAP_ALL},
>> + { NULL, 0},
>> +};
>> +
>> +u32 parse_setting(struct string_lookup *lookup, const char *name)
>> +{
>> + int i = 0;
>> + while (lookup[i].string != NULL) {
>> + if (strcmp(lookup[i].string, name) == 0)
>> + return lookup[i].val;
>> + ++i;
>> + }
>> + return -EINVAL;
>> +}
>> +
>> +u32 get_string_lookup(struct device_node *node, const char *name,
>> + struct string_lookup *lookup)
>> +{
>
> I have this feeling that swapping the names of the two functions above
> would reflect better their actual functionality.
I see what you mean. I'm happy to swap them if there are no objections.
>
>> + const char *string;
>> + int count, i, ret = 0;
>> +
>> + count = of_property_count_strings(node, name);
>> + if (count >= 0)
>> + for (i = 0; i < count; i++)
>> + if (of_property_read_string_index(node, name, i,
>> + &string) == 0)
>> + ret |= parse_setting(lookup, string);
>> + return ret;
>> +}
>> +
>> +int get_val(struct device_node *node, const char *string)
>> +{
>> + u32 ret = 0;
>> +
>> + if (of_property_read_u32(node, string, &ret))
>> + ret = -1;
>> + return ret;
>> +}
>> +
>> +struct clcd_panel *getPanel(struct device_node *node)
>> +{
>> + static struct clcd_panel panel;
>> +
>> + panel.mode.refresh = get_val(node, "refresh");
>> + panel.mode.xres = get_val(node, "xres");
>> + panel.mode.yres = get_val(node, "yres");
>> + panel.mode.pixclock = get_val(node, "pixclock");
>> + panel.mode.left_margin = get_val(node, "left_margin");
>> + panel.mode.right_margin = get_val(node, "right_margin");
>> + panel.mode.upper_margin = get_val(node, "upper_margin");
>> + panel.mode.lower_margin = get_val(node, "lower_margin");
>> + panel.mode.hsync_len = get_val(node, "hsync_len");
>> + panel.mode.vsync_len = get_val(node, "vsync_len");
>> + panel.mode.sync = get_val(node, "sync");
>> + panel.bpp = get_val(node, "bpp");
>> + panel.width = (signed short) get_val(node, "width");
>> + panel.height = (signed short) get_val(node, "height");
>> +
>> + panel.mode.vmode = get_string_lookup(node, "vmode", vmode_lookups);
>> + panel.tim2 = get_string_lookup(node, "tim2", tim2_lookups);
>> + panel.cntl = get_string_lookup(node, "cntl", cntl_lookups);
>> + panel.caps = get_string_lookup(node, "caps", caps_lookups);
>> +
>> + return &panel;
>> +}
>> +
>> +struct clcd_panel *clcdfb_get_panel(const char *name)
>> +{
>> + struct device_node *node = NULL;
>> + const char *mode;
>> + struct clcd_panel *panel = NULL;
>> +
>> + do {
>> + node = of_find_compatible_node(node, NULL, "panel");
>> + if (node)
>> + if (of_property_read_string(node, "mode", &mode) == 0)
>> + if (strcmp(mode, name) == 0) {
>> + panel = getPanel(node);
>> + panel->mode.name = name;
>> + }
>> + } while (node != NULL);
>> +
>> + return panel;
>> +}
>> +
>> +#ifdef CONFIG_OF
>
> shouldn't this #ifdef be earlier? you are calling of_property_read_string()
> and while there are empty definitions if CONFIG_OF is not defined, the code
> will do nothing in that case. Is that intended? The clcdfb_get_panel()
> function only gets called if CONFIG_OF *is* defined.
Agree.
>
>
>> +static int clcdfb_dt_init(struct clcd_fb *fb)
>> +{
>> + int err = 0;
>> + struct device_node *node;
>> + const char *mode;
>> + dma_addr_t dma;
>> + u32 use_dma;
>> + const __be32 *prop;
>> + int len, na, ns;
>> + phys_addr_t fb_base, fb_size;
>> +
>> + node = fb->dev->dev.of_node;
>> + if (!node)
>> + return -ENODEV;
>> +
>> + na = of_n_addr_cells(node);
>> + ns = of_n_size_cells(node);
>> +
>> + if (WARN_ON(of_property_read_string(node, "mode", &mode)))
>> + return -ENODEV;
>> +
>> + fb->panel = clcdfb_get_panel(mode);
>> + if (!fb->panel)
>> + return -EINVAL;
>> + fb->fb.fix.smem_len = fb->panel->mode.xres * fb->panel->mode.yres * 2;
>> +
>> + if (of_property_read_u32(node, "use_dma", &use_dma))
>
> I haven't seen any documentation for this property. What's the intended use?
Good point. Sorry for my ignorance, but is there a place I should put
such documentation?
When the A9 CoreTile uses the on-tile CLCD controller, it can use DMA
to handle the framebuffer. DMA is not available to the motherboard
CLCD controller.
I was trying to keep the properties simple, but they are more complex
than just the two settings: use_dma and framebuffer. If use_dma is
specified, the framebuffer property is not used; in this case, the
framebuffer is allocated by the DMA framework and the framebuffer
property is ignored. If use_dma is not present or is set to <0>, the
code uses the framebuffer property to specify the address.
>
>> + use_dma = 0;
>> + if (use_dma) {
>> + fb->fb.screen_base = dma_alloc_writecombine(&fb->dev->dev,
>> + fb->fb.fix.smem_len, &dma, GFP_KERNEL);
>> + if (!fb->fb.screen_base) {
>> + pr_err("CLCD: unable to map framebuffer\n");
>> + err = -ENOMEM;
>> + } else
>> + fb->fb.fix.smem_start = dma;
>> + } else {
>> + prop = of_get_property(node, "framebuffer", &len);
>> + if (WARN_ON(!prop || len < (na + ns) * sizeof(*prop)))
>> + return -EINVAL;
>> + fb_base = of_read_number(prop, na);
>> + fb_size = of_read_number(prop + na, ns);
>> +
>> + if (memblock_remove(fb_base, fb_size) != 0)
>> + return -EINVAL;
>> +
>> + fb->fb.fix.smem_start = fb_base;
>> + fb->fb.screen_base = ioremap_wc(fb->fb.fix.smem_start, fb_size);
>> + }
>> + return err;
>> +}
>> +#endif /* CONFIG_OF */
>> +
>> static int clcdfb_probe(struct amba_device *dev, const struct amba_id *id)
>> {
>> struct clcd_board *board = dev->dev.platform_data;
>> struct clcd_fb *fb;
>> int ret;
>>
>> +#ifdef CONFIG_OF
>> + if (dev->dev.of_node) {
>> + const __be32 *prop;
>> + int len, na, ns;
>> + phys_addr_t reg_base;
>> +
>> + na = of_n_addr_cells(dev->dev.of_node);
>> + ns = of_n_size_cells(dev->dev.of_node);
>> +
>> + prop = of_get_property(dev->dev.of_node, "reg", &len);
>> + if (WARN_ON(!prop || len < (na + ns) * sizeof(*prop)))
>> + return -EINVAL;
>> + reg_base = of_read_number(prop, na);
>> +
>> + if (dev->res.start != reg_base)
>> + return -EINVAL;
>> +
>> + if (!board) {
>> + board = kzalloc(sizeof(struct clcd_board), GFP_KERNEL);
>> + if (!board)
>> + return -EINVAL;
>> + board->name = "Device Tree CLCD PL111";
>> + board->caps = CLCD_CAP_5551 | CLCD_CAP_565;
>> + board->check = clcdfb_check;
>> + board->decode = clcdfb_decode;
>> + board->setup = clcdfb_dt_init;
>> + board->mmap = clcdfb_mmap_dma;
>> + board->remove = clcdfb_remove_dma;
>> + }
>> + }
>> +#endif /* CONFIG_OF */
>> +
>> if (!board)
>> return -EINVAL;
>>
>> --
>> 1.7.9.5
>>
>>
>
> --
> ====================
> | I would like to |
> | fix the world, |
> | but they're not |
> | giving me the |
> \ source code! /
> ---------------
> ¯\_(ツ)_/¯
>
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