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[v4,19/19] auxdisplay: ht16k33: Add LED support

Message ID 20210727140459.3767788-20-geert@linux-m68k.org (mailing list archive)
State Superseded
Headers show
Series auxdisplay: ht16k33: Add character display support | expand

Commit Message

Geert Uytterhoeven July 27, 2021, 2:04 p.m. UTC
Instantiate a single LED based on the "led" subnode in DT.
This allows the user to control display brightness and blinking (backed
by hardware support) through the LED class API and triggers, and exposes
the display color.  The LED will be named
"auxdisplay:<color>:<function>".

When running in dot-matrix mode and if no "led" subnode is found, the
driver falls back to the traditional backlight mode, to preserve
backwards compatibility.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
v4:
  - Add missing select LEDS_CLASS,

v3:
  - Remove unneeded C++ comment,
  - Use "err" instead of "error" to be consistent with existing driver
    naming style,
  - Make the creation of the LED device dependent on the presence of the
    "led" subnode in DT, so it can be used in dot-matrix mode too.
  - Use led_init_data() and devm_led_classdev_register_ext() to retrieve
    all LED properties from DT, instead of manual LED name construction
    based on just the "color" property,

v2:
  - Use "auxdisplay" instead of DRIVER_NAME in LED name.
---
 drivers/auxdisplay/Kconfig   |   1 +
 drivers/auxdisplay/ht16k33.c | 124 ++++++++++++++++++++++++++++++-----
 2 files changed, 108 insertions(+), 17 deletions(-)

Comments

Randy Dunlap July 27, 2021, 9:05 p.m. UTC | #1
On 7/27/21 7:04 AM, Geert Uytterhoeven wrote:
> Instantiate a single LED based on the "led" subnode in DT.
> This allows the user to control display brightness and blinking (backed
> by hardware support) through the LED class API and triggers, and exposes
> the display color.  The LED will be named
> "auxdisplay:<color>:<function>".
> 
> When running in dot-matrix mode and if no "led" subnode is found, the
> driver falls back to the traditional backlight mode, to preserve
> backwards compatibility.
> 
> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
> ---
> v4:
>   - Add missing select LEDS_CLASS,
> 
> v3:
>   - Remove unneeded C++ comment,
>   - Use "err" instead of "error" to be consistent with existing driver
>     naming style,
>   - Make the creation of the LED device dependent on the presence of the
>     "led" subnode in DT, so it can be used in dot-matrix mode too.
>   - Use led_init_data() and devm_led_classdev_register_ext() to retrieve
>     all LED properties from DT, instead of manual LED name construction
>     based on just the "color" property,
> 
> v2:
>   - Use "auxdisplay" instead of DRIVER_NAME in LED name.

Hi Geert,

Since LEDS_CLASS depends on NEW_LEDS, does this also need to
select NEW_LEDS?

and similar for INPUT_MATRIXKMAP: it depends on INPUT.

However, selecting (enabling) an entire subsystem is not a
preferable thing to do.

> ---
>  drivers/auxdisplay/Kconfig   |   1 +
>  drivers/auxdisplay/ht16k33.c | 124 ++++++++++++++++++++++++++++++-----
>  2 files changed, 108 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig
> index 42fc7b155de09dbc..7436b9a4edbe5450 100644
> --- a/drivers/auxdisplay/Kconfig
> +++ b/drivers/auxdisplay/Kconfig
> @@ -176,6 +176,7 @@ config HT16K33
>  	select FB_SYS_IMAGEBLIT
>  	select INPUT_MATRIXKMAP
>  	select FB_BACKLIGHT
> +	select LEDS_CLASS
>  	select LINEDISP
>  	help
>  	  Say yes here to add support for Holtek HT16K33, RAM mapping 16*8

thanks.
Geert Uytterhoeven July 28, 2021, 7:39 a.m. UTC | #2
Hi Randy,

On Tue, Jul 27, 2021 at 11:05 PM Randy Dunlap <rdunlap@infradead.org> wrote:
> On 7/27/21 7:04 AM, Geert Uytterhoeven wrote:
> > Instantiate a single LED based on the "led" subnode in DT.
> > This allows the user to control display brightness and blinking (backed
> > by hardware support) through the LED class API and triggers, and exposes
> > the display color.  The LED will be named
> > "auxdisplay:<color>:<function>".
> >
> > When running in dot-matrix mode and if no "led" subnode is found, the
> > driver falls back to the traditional backlight mode, to preserve
> > backwards compatibility.
> >
> > Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
> > ---
> > v4:
> >   - Add missing select LEDS_CLASS,

> Since LEDS_CLASS depends on NEW_LEDS, does this also need to
> select NEW_LEDS?

Right, I missed that.  It needs to select both NEW_LEDS and LED_CLASS.
Do I need to resend the whole series, or can this be fixed while
applying?

> and similar for INPUT_MATRIXKMAP: it depends on INPUT.

HT16K33 already depends on INPUT.

> However, selecting (enabling) an entire subsystem is not a
> preferable thing to do.

Unfortunately we have no choice, unless we untangle the depends/select
web first:

HT16K33 depends on NEW_LEDS, select LEDS_CLASS:

    drivers/leds/Kconfig:9:error: recursive dependency detected!
    drivers/leds/Kconfig:9:     symbol NEW_LEDS is selected by SENSORS_APPLESMC
    drivers/hwmon/Kconfig:324:  symbol SENSORS_APPLESMC depends on HWMON
    drivers/hwmon/Kconfig:6:    symbol HWMON is selected by EEEPC_LAPTOP
    drivers/platform/x86/Kconfig:305:   symbol EEEPC_LAPTOP depends on
ACPI_VIDEO

HT16K33 depends on LEDS_CLASS:

    drivers/leds/Kconfig:17:error: recursive dependency detected!
    drivers/leds/Kconfig:17:    symbol LEDS_CLASS depends on NEW_LEDS
    drivers/leds/Kconfig:9:     symbol NEW_LEDS is selected by SENSORS_APPLESMC
    drivers/hwmon/Kconfig:324:  symbol SENSORS_APPLESMC depends on HWMON
    drivers/hwmon/Kconfig:6:    symbol HWMON is selected by EEEPC_LAPTOP
    drivers/platform/x86/Kconfig:305:   symbol EEEPC_LAPTOP depends on
ACPI_VIDEO

> > --- a/drivers/auxdisplay/Kconfig
> > +++ b/drivers/auxdisplay/Kconfig
> > @@ -176,6 +176,7 @@ config HT16K33
> >       select FB_SYS_IMAGEBLIT
> >       select INPUT_MATRIXKMAP
> >       select FB_BACKLIGHT
> > +     select LEDS_CLASS
> >       select LINEDISP
> >       help
> >         Say yes here to add support for Holtek HT16K33, RAM mapping 16*8

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
diff mbox series

Patch

diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig
index 42fc7b155de09dbc..7436b9a4edbe5450 100644
--- a/drivers/auxdisplay/Kconfig
+++ b/drivers/auxdisplay/Kconfig
@@ -176,6 +176,7 @@  config HT16K33
 	select FB_SYS_IMAGEBLIT
 	select INPUT_MATRIXKMAP
 	select FB_BACKLIGHT
+	select LEDS_CLASS
 	select LINEDISP
 	help
 	  Say yes here to add support for Holtek HT16K33, RAM mapping 16*8
diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c
index 3b555e119e326cec..8c9a4a554a680ff2 100644
--- a/drivers/auxdisplay/ht16k33.c
+++ b/drivers/auxdisplay/ht16k33.c
@@ -18,6 +18,7 @@ 
 #include <linux/backlight.h>
 #include <linux/input.h>
 #include <linux/input/matrix_keypad.h>
+#include <linux/leds.h>
 #include <linux/workqueue.h>
 #include <linux/mm.h>
 
@@ -34,6 +35,10 @@ 
 
 #define REG_DISPLAY_SETUP		0x80
 #define REG_DISPLAY_SETUP_ON		BIT(0)
+#define REG_DISPLAY_SETUP_BLINK_OFF	(0 << 1)
+#define REG_DISPLAY_SETUP_BLINK_2HZ	(1 << 1)
+#define REG_DISPLAY_SETUP_BLINK_1HZ	(2 << 1)
+#define REG_DISPLAY_SETUP_BLINK_0HZ5	(3 << 1)
 
 #define REG_ROWINT_SET			0xA0
 #define REG_ROWINT_SET_INT_EN		BIT(0)
@@ -94,12 +99,14 @@  struct ht16k33_seg {
 struct ht16k33_priv {
 	struct i2c_client *client;
 	struct delayed_work work;
+	struct led_classdev led;
 	struct ht16k33_keypad keypad;
 	union {
 		struct ht16k33_fbdev fbdev;
 		struct ht16k33_seg seg;
 	};
 	enum display_type type;
+	uint8_t blink;
 };
 
 static const struct fb_fix_screeninfo ht16k33_fb_fix = {
@@ -158,7 +165,7 @@  static DEVICE_ATTR(map_seg14, 0644, map_seg_show, map_seg_store);
 
 static int ht16k33_display_on(struct ht16k33_priv *priv)
 {
-	uint8_t data = REG_DISPLAY_SETUP | REG_DISPLAY_SETUP_ON;
+	uint8_t data = REG_DISPLAY_SETUP | REG_DISPLAY_SETUP_ON | priv->blink;
 
 	return i2c_smbus_write_byte(priv->client, data);
 }
@@ -173,8 +180,10 @@  static int ht16k33_brightness_set(struct ht16k33_priv *priv,
 {
 	int err;
 
-	if (brightness == 0)
+	if (brightness == 0) {
+		priv->blink = REG_DISPLAY_SETUP_BLINK_OFF;
 		return ht16k33_display_off(priv);
+	}
 
 	err = ht16k33_display_on(priv);
 	if (err)
@@ -184,6 +193,49 @@  static int ht16k33_brightness_set(struct ht16k33_priv *priv,
 				    REG_BRIGHTNESS | (brightness - 1));
 }
 
+static int ht16k33_brightness_set_blocking(struct led_classdev *led_cdev,
+					   enum led_brightness brightness)
+{
+	struct ht16k33_priv *priv = container_of(led_cdev, struct ht16k33_priv,
+						 led);
+
+	return ht16k33_brightness_set(priv, brightness);
+}
+
+static int ht16k33_blink_set(struct led_classdev *led_cdev,
+			     unsigned long *delay_on, unsigned long *delay_off)
+{
+	struct ht16k33_priv *priv = container_of(led_cdev, struct ht16k33_priv,
+						 led);
+	unsigned int delay;
+	uint8_t blink;
+	int err;
+
+	if (!*delay_on && !*delay_off) {
+		blink = REG_DISPLAY_SETUP_BLINK_1HZ;
+		delay = 1000;
+	} else if (*delay_on <= 750) {
+		blink = REG_DISPLAY_SETUP_BLINK_2HZ;
+		delay = 500;
+	} else if (*delay_on <= 1500) {
+		blink = REG_DISPLAY_SETUP_BLINK_1HZ;
+		delay = 1000;
+	} else {
+		blink = REG_DISPLAY_SETUP_BLINK_0HZ5;
+		delay = 2000;
+	}
+
+	err = i2c_smbus_write_byte(priv->client,
+				   REG_DISPLAY_SETUP | REG_DISPLAY_SETUP_ON |
+				   blink);
+	if (err)
+		return err;
+
+	priv->blink = blink;
+	*delay_on = *delay_off = delay;
+	return 0;
+}
+
 static void ht16k33_fb_queue(struct ht16k33_priv *priv)
 {
 	struct ht16k33_fbdev *fbdev = &priv->fbdev;
@@ -425,6 +477,35 @@  static void ht16k33_seg14_update(struct work_struct *work)
 	i2c_smbus_write_i2c_block_data(priv->client, 0, ARRAY_SIZE(buf), buf);
 }
 
+static int ht16k33_led_probe(struct device *dev, struct led_classdev *led,
+			     unsigned int brightness)
+{
+	struct led_init_data init_data = {};
+	struct device_node *node;
+	int err;
+
+	/* The LED is optional */
+	node = of_get_child_by_name(dev->of_node, "led");
+	if (!node)
+		return 0;
+
+	led->brightness_set_blocking = ht16k33_brightness_set_blocking;
+	led->blink_set = ht16k33_blink_set;
+	led->flags = LED_CORE_SUSPENDRESUME;
+	led->brightness = brightness;
+	led->max_brightness = MAX_BRIGHTNESS;
+
+	init_data.fwnode = of_fwnode_handle(node);
+	init_data.devicename = "auxdisplay";
+	init_data.devname_mandatory = true;
+
+	err = devm_led_classdev_register_ext(dev, led, &init_data);
+	if (err)
+		dev_err(dev, "Failed to register LED\n");
+
+	return err;
+}
+
 static int ht16k33_keypad_probe(struct i2c_client *client,
 				struct ht16k33_keypad *keypad)
 {
@@ -498,24 +579,28 @@  static int ht16k33_fbdev_probe(struct device *dev, struct ht16k33_priv *priv,
 			       uint32_t brightness)
 {
 	struct ht16k33_fbdev *fbdev = &priv->fbdev;
-	struct backlight_properties bl_props;
-	struct backlight_device *bl;
+	struct backlight_device *bl = NULL;
 	int err;
 
-	/* Backlight */
-	memset(&bl_props, 0, sizeof(struct backlight_properties));
-	bl_props.type = BACKLIGHT_RAW;
-	bl_props.max_brightness = MAX_BRIGHTNESS;
+	if (!priv->led.dev) {
+		/* backwards compatibility with DT lacking an led subnode */
+		struct backlight_properties bl_props;
 
-	bl = devm_backlight_device_register(dev, DRIVER_NAME"-bl", dev, priv,
-					    &ht16k33_bl_ops, &bl_props);
-	if (IS_ERR(bl)) {
-		dev_err(dev, "failed to register backlight\n");
-		return PTR_ERR(bl);
-	}
+		memset(&bl_props, 0, sizeof(struct backlight_properties));
+		bl_props.type = BACKLIGHT_RAW;
+		bl_props.max_brightness = MAX_BRIGHTNESS;
+
+		bl = devm_backlight_device_register(dev, DRIVER_NAME"-bl", dev,
+						    priv, &ht16k33_bl_ops,
+						    &bl_props);
+		if (IS_ERR(bl)) {
+			dev_err(dev, "failed to register backlight\n");
+			return PTR_ERR(bl);
+		}
 
-	bl->props.brightness = brightness;
-	ht16k33_bl_update_status(bl);
+		bl->props.brightness = brightness;
+		ht16k33_bl_update_status(bl);
+	}
 
 	/* Framebuffer (2 bytes per column) */
 	BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
@@ -575,7 +660,7 @@  static int ht16k33_seg_probe(struct device *dev, struct ht16k33_priv *priv,
 	struct ht16k33_seg *seg = &priv->seg;
 	int err;
 
-	err = ht16k33_brightness_set(priv, MAX_BRIGHTNESS);
+	err = ht16k33_brightness_set(priv, brightness);
 	if (err)
 		return err;
 
@@ -653,6 +738,11 @@  static int ht16k33_probe(struct i2c_client *client)
 		dft_brightness = MAX_BRIGHTNESS;
 	}
 
+	/* LED */
+	err = ht16k33_led_probe(dev, &priv->led, dft_brightness);
+	if (err)
+		return err;
+
 	/* Keypad */
 	if (client->irq > 0) {
 		err = ht16k33_keypad_probe(client, &priv->keypad);