CC linux-leds (which I intended, but forgot to add) cover letter at https://lore.kernel.org/linux-devicetree/20210322144848.1065067-1-geert@xxxxxxxxxxxxxx/ On Tue, Mar 23, 2021 at 11:08 AM Robin van der Gracht <robin@xxxxxxxxxxx> wrote: > > On 2021-03-22 15:48, Geert Uytterhoeven wrote: > > Instantiate a single LED for a segment display. This allows the user > > to > > control display brightness and blinking through the LED class API and > > triggers, and exposes the display color. > > > > Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > > --- > > For setting display brightness, this could use the existing backlight > > support for frame buffer devices instantiated for dot-matrix displays. > > However, using the leds subsystem instead has the advantage that the > > driver can make use of the HT16K33's hardware blinking support, and can > > expose the display color. > > --- > > drivers/auxdisplay/ht16k33.c | 81 ++++++++++++++++++++++++++++++++++-- > > 1 file changed, 77 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/auxdisplay/ht16k33.c > > b/drivers/auxdisplay/ht16k33.c > > index 0b502a6039f89c6b..5821addd9aec5633 100644 > > --- a/drivers/auxdisplay/ht16k33.c > > +++ b/drivers/auxdisplay/ht16k33.c > > @@ -29,6 +29,7 @@ > > #include <asm/unaligned.h> > > > > #include "line-display.h" > > +#include "../leds/leds.h" /* for led_colors[] */ > > > > /* Registers */ > > #define REG_SYSTEM_SETUP 0x20 > > @@ -36,6 +37,10 @@ > > > > #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) > > @@ -57,6 +62,8 @@ > > #define BYTES_PER_ROW (HT16K33_MATRIX_LED_MAX_ROWS / 8) > > #define HT16K33_FB_SIZE (HT16K33_MATRIX_LED_MAX_COLS * BYTES_PER_ROW) > > > > +#define COLOR_DEFAULT LED_COLOR_ID_RED > > + > > enum display_type { > > DISP_MATRIX = 0, > > DISP_QUAD_7SEG, > > @@ -85,6 +92,7 @@ struct ht16k33_fbdev { > > > > struct ht16k33_seg { > > struct linedisp linedisp; > > + struct led_classdev led; > > union { > > struct seg7_conversion_map seg7; > > struct seg14_conversion_map seg14; > > @@ -102,6 +110,7 @@ struct ht16k33_priv { > > struct ht16k33_seg seg; > > }; > > enum display_type type; > > + uint8_t blink; > > }; > > > > static const struct fb_fix_screeninfo ht16k33_fb_fix = { > > @@ -160,7 +169,7 @@ 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); > > } > > @@ -175,8 +184,11 @@ static int ht16k33_brightness_set(struct > > ht16k33_priv *priv, > > { > > int error; > > > > - if (brightness == 0) > > + if (brightness == 0) { > > + // Disable blink mode > > + priv->blink = REG_DISPLAY_SETUP_BLINK_OFF; > > return ht16k33_display_off(priv); > > + } > > > > error = ht16k33_display_on(priv); > > if (error) > > @@ -186,6 +198,49 @@ 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, > > + seg.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, > > + seg.led); > > + unsigned int delay; > > + uint8_t blink; > > + int error; > > + > > + 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; > > + } > > + > > + error = i2c_smbus_write_byte(priv->client, > > + REG_DISPLAY_SETUP | REG_DISPLAY_SETUP_ON | > > + blink); > > + if (error) > > + return error; > > + > > + 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; > > @@ -578,11 +633,29 @@ static int ht16k33_fbdev_probe(struct i2c_client > > *client, > > static int ht16k33_seg_probe(struct i2c_client *client, > > struct ht16k33_priv *priv, uint32_t brightness) > > { > > - struct ht16k33_seg *seg = &priv->seg; > > struct device *dev = &client->dev; > > + struct device_node *node = dev->of_node; > > + struct ht16k33_seg *seg = &priv->seg; > > + u32 color = COLOR_DEFAULT; > > int err; > > > > - err = ht16k33_brightness_set(priv, MAX_BRIGHTNESS); > > + of_property_read_u32(node, "color", &color); > > + seg->led.name = devm_kasprintf(dev, GFP_KERNEL, > > + DRIVER_NAME ":%s:" LED_FUNCTION_BACKLIGHT, > > + color < LED_COLOR_ID_MAX ? led_colors[color] : ""); > > + seg->led.brightness_set_blocking = ht16k33_brightness_set_blocking; > > + seg->led.blink_set = ht16k33_blink_set; > > + seg->led.flags = LED_CORE_SUSPENDRESUME; > > + seg->led.brightness = brightness; > > + seg->led.max_brightness = MAX_BRIGHTNESS; > > + > > + err = devm_led_classdev_register(dev, &seg->led); > > + if (err) { > > + dev_err(dev, "Failed to register LED\n"); > > + return err; > > + } > > + > > + err = ht16k33_brightness_set(priv, seg->led.brightness); > > if (err) > > return err; > > The LED class can pretty much do what the backlight class can and more. > > Maybe we can stop registering a backlight device in the fbdev case and > register a led device for both. This makes the code cleaner and drops > a dependency but will break backwards compatibility. > > I'd prefer a single solution that covers both use cases, but I'm not > sure about the 'breaking backwards compatibility' consequence... > > Groetjes / Kind regards, > Robin van der Gracht
