Subject: Re: [RFC 19/25] leds: tm1628: Add 7-segment display support

From: Pavel Machek <[email-masked]>
Date: Sat, 21 Dec 2019 21:23:33 +0100

Hi!

> Detect DT child nodes covering more than one LED component and implement
> a text to 7-segment display mapping.

Up to here, I seen nothing totally crazy.

But I'd prefer not to have this in the LED subsystem.

Best regards,
									Pavel

> Signed-off-by: Andreas Färber <[email-masked]>
> ---
>  drivers/leds/leds-tm1628.c | 230 ++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 229 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/leds/leds-tm1628.c b/drivers/leds/leds-tm1628.c
> index 8a8fd1562853..e2c2a5d91596 100644
> --- a/drivers/leds/leds-tm1628.c
> +++ b/drivers/leds/leds-tm1628.c
> @@ -47,6 +47,15 @@ struct tm1628_info {
>  	int				default_pwm;
>  };
>  
> +struct tm1628_segment {
> +	u32 grid;
> +	u32 seg;
> +};
> +
> +struct tm1628_display {
> +	struct tm1628_segment segments[8];
> +};
> +
>  struct tm1628_led {
>  	struct led_classdev	leddev;
>  	struct tm1628		*ctrl;
> @@ -62,6 +71,8 @@ struct tm1628 {
>  	int				mode_index;
>  	int				pwm_index;
>  	u8				data[14];
> +	unsigned int			num_displays;
> +	struct tm1628_display		*displays;
>  	unsigned int			num_leds;
>  	struct tm1628_led		leds[];
>  };
> @@ -253,6 +264,215 @@ static int tm1628_register_led(struct tm1628 *s,
>  	return devm_led_classdev_register_ext(dev, &led->leddev, &init_data);
>  }
>  
> +#define SSD_TOP			BIT(0)
> +#define SSD_TOP_RIGHT		BIT(1)
> +#define SSD_BOTTOM_RIGHT	BIT(2)
> +#define SSD_BOTTOM		BIT(3)
> +#define SSD_BOTTOM_LEFT		BIT(4)
> +#define SSD_TOP_LEFT		BIT(5)
> +#define SSD_MIDDLE		BIT(6)
> +#define SSD_DOT			BIT(7)
> +
> +struct tm1628_ssd_char {
> +	char ch;
> +	u8 segs;
> +};
> +
> +static const struct tm1628_ssd_char tm1628_char_ssd_map[] = {
> +	{ '0', SSD_TOP | SSD_TOP_LEFT | SSD_TOP_RIGHT |
> +	       SSD_BOTTOM_LEFT | SSD_BOTTOM_RIGHT | SSD_BOTTOM },
> +	{ '1', SSD_TOP_RIGHT | SSD_BOTTOM_RIGHT },
> +	{ '2', SSD_TOP | SSD_TOP_RIGHT | SSD_MIDDLE | SSD_BOTTOM_LEFT | SSD_BOTTOM },
> +	{ '3', SSD_TOP | SSD_TOP_RIGHT | SSD_MIDDLE | SSD_BOTTOM_RIGHT | SSD_BOTTOM },
> +	{ '4', SSD_TOP_LEFT | SSD_TOP_RIGHT | SSD_MIDDLE | SSD_BOTTOM_RIGHT },
> +	{ '5', SSD_TOP | SSD_TOP_LEFT | SSD_MIDDLE | SSD_BOTTOM_RIGHT | SSD_BOTTOM },
> +	{ '6', SSD_TOP | SSD_TOP_LEFT | SSD_MIDDLE | SSD_BOTTOM_LEFT | SSD_BOTTOM_RIGHT | SSD_BOTTOM },
> +	{ '7', SSD_TOP | SSD_TOP_RIGHT | SSD_BOTTOM_RIGHT },
> +	{ '8', SSD_TOP | SSD_TOP_LEFT | SSD_TOP_RIGHT | SSD_MIDDLE |
> +	       SSD_BOTTOM_LEFT | SSD_BOTTOM_RIGHT | SSD_BOTTOM },
> +	{ '9', SSD_TOP | SSD_TOP_LEFT | SSD_TOP_RIGHT | SSD_MIDDLE |
> +	       SSD_BOTTOM_RIGHT | SSD_BOTTOM },
> +	{ 'A', SSD_TOP | SSD_TOP_LEFT | SSD_TOP_RIGHT | SSD_MIDDLE |
> +	       SSD_BOTTOM_LEFT | SSD_BOTTOM_RIGHT },
> +	{ 'B', SSD_TOP | SSD_TOP_LEFT | SSD_TOP_RIGHT | SSD_MIDDLE |
> +	       SSD_BOTTOM_LEFT | SSD_BOTTOM_RIGHT | SSD_BOTTOM },
> +	{ 'C', SSD_TOP | SSD_TOP_LEFT | SSD_BOTTOM_LEFT | SSD_BOTTOM },
> +	{ 'D', SSD_TOP | SSD_TOP_LEFT | SSD_TOP_RIGHT |
> +	       SSD_BOTTOM_LEFT | SSD_BOTTOM_RIGHT | SSD_BOTTOM },
> +	{ 'E', SSD_TOP | SSD_TOP_LEFT | SSD_MIDDLE | SSD_BOTTOM_LEFT | SSD_BOTTOM },
> +	{ 'F', SSD_TOP | SSD_TOP_LEFT | SSD_MIDDLE | SSD_BOTTOM_LEFT },
> +	{ 'G', SSD_TOP | SSD_TOP_LEFT | SSD_BOTTOM_LEFT | SSD_BOTTOM | SSD_BOTTOM_RIGHT },
> +	{ 'H', SSD_TOP_LEFT | SSD_TOP_RIGHT | SSD_MIDDLE |
> +	       SSD_BOTTOM_LEFT | SSD_BOTTOM_RIGHT },
> +	{ 'I', SSD_TOP_LEFT | SSD_BOTTOM_LEFT },
> +	{ 'J', SSD_TOP | SSD_TOP_RIGHT | SSD_BOTTOM_RIGHT | SSD_BOTTOM },
> +	{ 'K', SSD_TOP_LEFT | SSD_TOP_RIGHT | SSD_MIDDLE |
> +	       SSD_BOTTOM_LEFT | SSD_BOTTOM_RIGHT },
> +	{ 'L', SSD_TOP_LEFT | SSD_BOTTOM_LEFT | SSD_BOTTOM },
> +	{ 'O', SSD_TOP | SSD_TOP_LEFT | SSD_TOP_RIGHT |
> +	       SSD_BOTTOM_LEFT | SSD_BOTTOM_RIGHT | SSD_BOTTOM },
> +	{ 'P', SSD_TOP | SSD_TOP_LEFT | SSD_TOP_RIGHT | SSD_MIDDLE |
> +	       SSD_BOTTOM_LEFT },
> +	{ 'Q', SSD_TOP | SSD_TOP_LEFT | SSD_TOP_RIGHT |
> +	       SSD_BOTTOM_LEFT | SSD_BOTTOM_RIGHT | SSD_BOTTOM },
> +	{ 'R', SSD_TOP | SSD_TOP_LEFT | SSD_TOP_RIGHT | SSD_MIDDLE |
> +	       SSD_BOTTOM_LEFT | SSD_BOTTOM_RIGHT },
> +	{ 'S', SSD_TOP | SSD_TOP_LEFT | SSD_MIDDLE | SSD_BOTTOM_RIGHT | SSD_BOTTOM },
> +	{ 'T', SSD_TOP | SSD_TOP_LEFT | SSD_BOTTOM_LEFT },
> +	{ 'U', SSD_TOP_LEFT | SSD_BOTTOM_LEFT | SSD_BOTTOM | SSD_BOTTOM_RIGHT | SSD_TOP_RIGHT },
> +	{ 'V', SSD_TOP_LEFT | SSD_BOTTOM_LEFT | SSD_BOTTOM | SSD_BOTTOM_RIGHT | SSD_TOP_RIGHT },
> +	{ 'W', SSD_TOP_LEFT | SSD_BOTTOM_LEFT | SSD_BOTTOM | SSD_BOTTOM_RIGHT | SSD_TOP_RIGHT },
> +	{ 'Z', SSD_TOP | SSD_TOP_RIGHT | SSD_MIDDLE | SSD_BOTTOM_LEFT | SSD_BOTTOM },
> +	{ 'b', SSD_TOP_LEFT | SSD_MIDDLE | SSD_BOTTOM_LEFT | SSD_BOTTOM | SSD_BOTTOM_RIGHT },
> +	{ 'l', SSD_TOP_LEFT | SSD_BOTTOM_LEFT },
> +	{ 'o', SSD_MIDDLE | SSD_BOTTOM_LEFT | SSD_BOTTOM | SSD_BOTTOM_RIGHT },
> +	{ 't', SSD_TOP_LEFT | SSD_MIDDLE | SSD_BOTTOM_LEFT | SSD_BOTTOM },
> +	{ 'u', SSD_BOTTOM_LEFT | SSD_BOTTOM | SSD_BOTTOM_RIGHT },
> +	{ 'v', SSD_BOTTOM_LEFT | SSD_BOTTOM | SSD_BOTTOM_RIGHT },
> +	{ 'w', SSD_BOTTOM_LEFT | SSD_BOTTOM | SSD_BOTTOM_RIGHT },
> +	{ '-', SSD_MIDDLE },
> +	{ '_', SSD_BOTTOM },
> +	{ '.', SSD_DOT },
> +};
> +
> +static u8 tm1628_get_char_ssd_map(char ch)
> +{
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(tm1628_char_ssd_map); i++) {
> +		if (tm1628_char_ssd_map[i].ch == ch)
> +			return tm1628_char_ssd_map[i].segs;
> +	}
> +
> +	return 0x0;
> +}
> +
> +static int tm1628_display_apply_map(struct tm1628 *s,
> +	struct tm1628_display *display, u8 map)
> +{
> +	struct tm1628_segment *segment;
> +	int i;
> +
> +	for (i = 0; i < 8; i++) {
> +		segment = &display->segments[i];
> +		tm1628_set_led(s, segment->grid, segment->seg, map & BIT(i));
> +	}
> +
> +	return 0;
> +}
> +
> +static ssize_t text_store(struct device *dev,
> +	struct device_attribute *attr, const char *buf, size_t count)
> +{
> +	struct tm1628 *s = dev_get_drvdata(dev);
> +	size_t offset, len = count;
> +	u8 map;
> +	int i, ret;
> +
> +	if (len > 0 && buf[len - 1] == '\n')
> +		len--;
> +
> +	for (i = 0, offset = 0; i < s->num_displays; i++) {
> +		if (offset < len) {
> +			map = tm1628_get_char_ssd_map(buf[offset]);
> +			offset++;
> +		} else
> +			map = 0x0;
> +
> +		tm1628_display_apply_map(s, &s->displays[i], map);
> +	}
> +
> +	ret = tm1628_set_address(s->spi, 0x0);
> +	if (ret)
> +		return ret;
> +
> +	ret = tm1628_write_data(s->spi, s->data, 14);
> +	if (ret)
> +		return ret;
> +
> +	return count;
> +}
> +
> +static struct device_attribute tm1628_attr =
> +	__ATTR_WO(text);
> +
> +static int tm1628_register_display(struct tm1628 *s,
> +	struct fwnode_handle *node)
> +{
> +	struct device *dev = &s->spi->dev;
> +	struct tm1628_display *display;
> +	u32 *reg;
> +	u32 grid, seg;
> +	int i, j, ret, reg_count;
> +
> +	reg_count = fwnode_property_count_u32(node, "reg");
> +	if (reg_count < 0)
> +		return reg_count;
> +
> +	if (reg_count % 2) {
> +		dev_warn(dev, "Ignoring extra cell in %s reg property\n",
> +			 fwnode_get_name(node));
> +		reg_count--;
> +	}
> +
> +	if (s->displays) {
> +		dev_warn(dev, "Only one display supported\n");
> +		return -EINVAL;
> +	}
> +
> +	s->num_displays = reg_count >> 1;
> +
> +	reg = devm_kzalloc(dev, reg_count * sizeof(*reg), GFP_KERNEL);
> +	if (!reg)
> +		return -ENOMEM;
> +
> +	ret = fwnode_property_read_u32_array(node, "reg", reg, reg_count);
> +	if (ret) {
> +		dev_err(dev, "Reading %s reg property failed (%d)\n",
> +			fwnode_get_name(node), ret);
> +		return ret;
> +	}
> +
> +	s->displays = devm_kzalloc(dev, s->num_displays * sizeof(*s->displays), GFP_KERNEL);
> +	if (!s->displays)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < s->num_displays; i++) {
> +		display = &s->displays[i];
> +		grid = reg[i * 2];
> +		seg  = reg[i * 2 + 1];
> +		if (grid == 0 && seg != 0) {
> +			if (!tm1628_is_valid_seg(s, seg)) {
> +				dev_warn(dev, "%s reg out of range\n", fwnode_get_name(node));
> +				return -EINVAL;
> +			}
> +			grid = s->info->modes[s->mode_index].grid_mask;
> +			for (j = 0; grid && j < 7; j++) {
> +				display->segments[j].seg = seg;
> +				display->segments[j].grid = __ffs(grid);
> +				grid &= ~BIT(display->segments[j].grid);
> +			}
> +		} else if (grid != 0 && seg == 0) {
> +			if (!tm1628_is_valid_grid(s, grid)) {
> +				dev_warn(dev, "%s reg out of range\n", fwnode_get_name(node));
> +				return -EINVAL;
> +			}
> +			seg = s->info->modes[s->mode_index].seg_mask;
> +			for (j = 0; seg && j < 8; j++) {
> +				display->segments[j].grid = grid;
> +				display->segments[j].seg = __ffs(seg);
> +				seg &= ~BIT(display->segments[j].seg);
> +			}
> +		}
> +	}
> +
> +	devm_kfree(dev, reg);
> +
> +	device_create_file(dev, &tm1628_attr);
> +
> +	return 0;
> +}
> +
>  /* Work around __builtin_popcount() */
>  static u32 tm1628_grid_popcount(u8 grid_mask)
>  {
> @@ -325,7 +545,7 @@ static int tm1628_spi_probe(struct spi_device *spi)
>  			return ret;
>  		}
>  
> -		if (fwnode_property_count_u32(child, "reg") == 2) {
> +		if (reg[0] != 0 && reg[1] != 0 && fwnode_property_count_u32(child, "reg") == 2) {
>  			ret = tm1628_register_led(s, child, reg[0], reg[1], &s->leds[i++]);
>  			if (ret && ret != -EINVAL) {
>  				dev_err(&spi->dev, "Failed to register LED %s (%d)\n",
> @@ -334,6 +554,14 @@ static int tm1628_spi_probe(struct spi_device *spi)
>  				return ret;
>  			}
>  			s->num_leds++;
> +		} else {
> +			ret = tm1628_register_display(s, child);
> +			if (ret) {
> +				dev_err(&spi->dev, "Failed to register display %s (%d)\n",
> +					fwnode_get_name(child), ret);
> +				fwnode_handle_put(child);
> +				return ret;
> +			}
>  		}
>  	}
>  

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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