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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Robin van der Gracht <robin@protonic.nl>,
	Rob Herring <robh+dt@kernel.org>, Miguel Ojeda <ojeda@kernel.org>,
	Paul Burton <paulburton@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Pavel Machek <pavel@ucw.cz>, Marek Behun <marek.behun@nic.cz>
Cc: devicetree@vger.kernel.org, linux-leds@vger.kernel.org,
	linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
	Geert Uytterhoeven <geert@linux-m68k.org>
Subject: [PATCH v4 08/19] auxdisplay: linedisp: Add support for changing scroll rate
Date: Tue, 27 Jul 2021 16:04:48 +0200	[thread overview]
Message-ID: <20210727140459.3767788-9-geert@linux-m68k.org> (raw)
In-Reply-To: <20210727140459.3767788-1-geert@linux-m68k.org>

If the message to display is longer than the number of characters that
the display can show, the message will be scrolled.  Currently the
scroll rate is fixed, moving every 500 ms.

Add support for changing the scroll rate through a "scroll_step_ms"
device attribute in sysfs.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
v4:
  - No changes,

v3:
  - No changes,

v2:
  - No changes.
---
 drivers/auxdisplay/line-display.c | 37 +++++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/auxdisplay/line-display.c b/drivers/auxdisplay/line-display.c
index 3f35199bc39f511f..03e7f104aa1add32 100644
--- a/drivers/auxdisplay/line-display.c
+++ b/drivers/auxdisplay/line-display.c
@@ -19,6 +19,8 @@
 
 #include "line-display.h"
 
+#define DEFAULT_SCROLL_RATE	(HZ / 2)
+
 /**
  * linedisp_scroll() - scroll the display by a character
  * @t: really a pointer to the private data structure
@@ -50,7 +52,7 @@ static void linedisp_scroll(struct timer_list *t)
 	linedisp->scroll_pos %= linedisp->message_len;
 
 	/* rearm the timer */
-	if (linedisp->message_len > num_chars)
+	if (linedisp->message_len > num_chars && linedisp->scroll_rate)
 		mod_timer(&linedisp->timer, jiffies + linedisp->scroll_rate);
 }
 
@@ -149,8 +151,39 @@ static ssize_t message_store(struct device *dev, struct device_attribute *attr,
 
 static DEVICE_ATTR_RW(message);
 
+static ssize_t scroll_step_ms_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct linedisp *linedisp = container_of(dev, struct linedisp, dev);
+
+	return sysfs_emit(buf, "%u\n", jiffies_to_msecs(linedisp->scroll_rate));
+}
+
+static ssize_t scroll_step_ms_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t count)
+{
+	struct linedisp *linedisp = container_of(dev, struct linedisp, dev);
+	unsigned int ms;
+
+	if (kstrtouint(buf, 10, &ms) != 0)
+		return -EINVAL;
+
+	linedisp->scroll_rate = msecs_to_jiffies(ms);
+	if (linedisp->message && linedisp->message_len > linedisp->num_chars) {
+		del_timer_sync(&linedisp->timer);
+		if (linedisp->scroll_rate)
+			linedisp_scroll(&linedisp->timer);
+	}
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(scroll_step_ms);
+
 static struct attribute *linedisp_attrs[] = {
 	&dev_attr_message.attr,
+	&dev_attr_scroll_step_ms.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(linedisp);
@@ -182,7 +215,7 @@ int linedisp_register(struct linedisp *linedisp, struct device *parent,
 	linedisp->update = update;
 	linedisp->buf = buf;
 	linedisp->num_chars = num_chars;
-	linedisp->scroll_rate = HZ / 2;
+	linedisp->scroll_rate = DEFAULT_SCROLL_RATE;
 
 	device_initialize(&linedisp->dev);
 	dev_set_name(&linedisp->dev, "linedisp.%lu",
-- 
2.25.1


  parent reply	other threads:[~2021-07-27 14:05 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-27 14:04 [PATCH v4 00/19] auxdisplay: ht16k33: Add character display support Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 01/19] uapi: Add <linux/map_to_14segment.h> Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 02/19] dt-bindings: auxdisplay: ht16k33: Document Adafruit segment displays Geert Uytterhoeven
2021-08-02 20:40   ` Rob Herring
2021-07-27 14:04 ` [PATCH v4 03/19] auxdisplay: img-ascii-lcd: Fix lock-up when displaying empty string Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 04/19] auxdisplay: img-ascii-lcd: Add helper variable dev Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 05/19] auxdisplay: img-ascii-lcd: Convert device attribute to sysfs_emit() Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 06/19] auxdisplay: Extract character line display core support Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 07/19] auxdisplay: linedisp: Use kmemdup_nul() helper Geert Uytterhoeven
2021-07-27 14:04 ` Geert Uytterhoeven [this message]
2021-07-27 14:04 ` [PATCH v4 09/19] auxdisplay: ht16k33: Connect backlight to fbdev Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 10/19] auxdisplay: ht16k33: Use HT16K33_FB_SIZE in ht16k33_initialize() Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 11/19] auxdisplay: ht16k33: Remove unneeded error check in keypad probe() Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 12/19] auxdisplay: ht16k33: Convert to simple i2c probe function Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 13/19] auxdisplay: ht16k33: Add helper variable dev Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 14/19] auxdisplay: ht16k33: Move delayed work Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 15/19] auxdisplay: ht16k33: Extract ht16k33_brightness_set() Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 16/19] auxdisplay: ht16k33: Extract frame buffer probing Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 17/19] auxdisplay: ht16k33: Add support for segment displays Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 18/19] dt-bindings: auxdisplay: ht16k33: Document LED subnode Geert Uytterhoeven
2021-07-27 14:04 ` [PATCH v4 19/19] auxdisplay: ht16k33: Add LED support Geert Uytterhoeven
2021-07-27 21:05   ` Randy Dunlap
2021-07-28  7:39     ` Geert Uytterhoeven

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