Commit 899383f9 authored by Chris Packham's avatar Chris Packham Committed by Andy Shevchenko
Browse files

auxdisplay: Add 7-segment LED display driver 



Add a driver for a 7-segment LED display. At the moment only one
character is supported but it should be possible to expand this to
support more characters and/or 14-segment displays in the future.

Signed-off-by: default avatarChris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
parent a9bcd02f

drivers/auxdisplay/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -211,6 +211,17 @@ config ARM_CHARLCD 
	  line and the Linux version on the second line, but that's

	  still useful.



config SEG_LED_GPIO

	tristate "Generic 7-segment LED display"

	depends on GPIOLIB || COMPILE_TEST

	select LINEDISP

	help

	  This driver supports a generic 7-segment LED display made up

	  of GPIO pins connected to the individual segments.



	  This driver can also be built as a module. If so, the module

	  will be called seg-led-gpio.



menuconfig PARPORT_PANEL

	tristate "Parallel port LCD/Keypad Panel support"

	depends on PARPORT

drivers/auxdisplay/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -15,3 +15,4 @@ obj-$(CONFIG_PARPORT_PANEL) += panel.o 
obj-$(CONFIG_LCD2S)		+= lcd2s.o

obj-$(CONFIG_LINEDISP)		+= line-display.o

obj-$(CONFIG_MAX6959)		+= max6959.o

obj-$(CONFIG_SEG_LED_GPIO)	+= seg-led-gpio.o

drivers/auxdisplay/seg-led-gpio.c

0 → 100644
+112 −0
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// SPDX-License-Identifier: GPL-2.0

/*

 * Driver for a 7-segment LED display

 *

 * The decimal point LED present on some devices is currently not

 * supported.

 *

 * Copyright (C) Allied Telesis Labs

 */



#include <linux/bitmap.h>

#include <linux/container_of.h>

#include <linux/errno.h>

#include <linux/gpio/consumer.h>

#include <linux/map_to_7segment.h>

#include <linux/mod_devicetable.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/types.h>

#include <linux/workqueue.h>



#include "line-display.h"



struct seg_led_priv {

	struct linedisp linedisp;

	struct delayed_work work;

	struct gpio_descs *segment_gpios;

};



static void seg_led_update(struct work_struct *work)

{

	struct seg_led_priv *priv = container_of(work, struct seg_led_priv, work.work);

	struct linedisp *linedisp = &priv->linedisp;

	struct linedisp_map *map = linedisp->map;

	DECLARE_BITMAP(values, 8) = { };



	bitmap_set_value8(values, map_to_seg7(&map->map.seg7, linedisp->buf[0]), 0);



	gpiod_set_array_value_cansleep(priv->segment_gpios->ndescs, priv->segment_gpios->desc,

				       priv->segment_gpios->info, values);

}



static int seg_led_linedisp_get_map_type(struct linedisp *linedisp)

{

	struct seg_led_priv *priv = container_of(linedisp, struct seg_led_priv, linedisp);



	INIT_DELAYED_WORK(&priv->work, seg_led_update);

	return LINEDISP_MAP_SEG7;

}



static void seg_led_linedisp_update(struct linedisp *linedisp)

{

	struct seg_led_priv *priv = container_of(linedisp, struct seg_led_priv, linedisp);



	schedule_delayed_work(&priv->work, 0);

}



static const struct linedisp_ops seg_led_linedisp_ops = {

	.get_map_type = seg_led_linedisp_get_map_type,

	.update = seg_led_linedisp_update,

};



static int seg_led_probe(struct platform_device *pdev)

{

	struct seg_led_priv *priv;

	struct device *dev = &pdev->dev;



	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);

	if (!priv)

		return -ENOMEM;



	platform_set_drvdata(pdev, priv);



	priv->segment_gpios = devm_gpiod_get_array(dev, "segment", GPIOD_OUT_LOW);

	if (IS_ERR(priv->segment_gpios))

		return PTR_ERR(priv->segment_gpios);



	if (priv->segment_gpios->ndescs < 7 || priv->segment_gpios->ndescs > 8)

		return -EINVAL;



	return linedisp_register(&priv->linedisp, dev, 1, &seg_led_linedisp_ops);

}



static int seg_led_remove(struct platform_device *pdev)

{

	struct seg_led_priv *priv = platform_get_drvdata(pdev);



	cancel_delayed_work_sync(&priv->work);

	linedisp_unregister(&priv->linedisp);



	return 0;

}



static const struct of_device_id seg_led_of_match[] = {

	{ .compatible = "gpio-7-segment"},

	{}

};

MODULE_DEVICE_TABLE(of, seg_led_of_match);



static struct platform_driver seg_led_driver = {

	.probe = seg_led_probe,

	.remove = seg_led_remove,

	.driver = {

		.name = "seg-led-gpio",

		.of_match_table = seg_led_of_match,

	},

};

module_platform_driver(seg_led_driver);



MODULE_AUTHOR("Chris Packham <chris.packham@alliedtelesis.co.nz>");

MODULE_DESCRIPTION("7 segment LED driver");

MODULE_LICENSE("GPL");