kernel bump to 4.19.23

See: https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=224931

boot/overlays/README

@@ -56,23 +56,29 @@ have its contents deleted (or commented out).
 Using Overlays
 ==============
 
-Overlays are loaded using the "dtoverlay" directive. As an example, consider
-the popular lirc-rpi module, the Linux Infrared Remote Control driver. In the
-pre-DT world this would be loaded from /etc/modules, with an explicit
-"modprobe lirc-rpi" command, or programmatically by lircd. With DT enabled,
-this becomes a line in config.txt:
+Overlays are loaded using the "dtoverlay" config.txt setting. As an example,
+consider I2C Real Time Clock drivers. In the pre-DT world these would be loaded
+by writing a magic string comprising a device identifier and an I2C address to
+a special file in /sys/class/i2c-adapter, having first loaded the driver for
+the I2C interface and the RTC device - something like this:
 
-    dtoverlay=lirc-rpi
+    modprobe i2c-bcm2835
+    modprobe rtc-ds1307
+    echo ds1307 0x68 > /sys/class/i2c-adapter/i2c-1/new_device
 
-This causes the file /boot/overlays/lirc-rpi.dtbo to be loaded. By
-default it will use GPIOs 17 (out) and 18 (in), but this can be modified using
-DT parameters:
+With DT enabled, this becomes a line in config.txt:
 
-    dtoverlay=lirc-rpi,gpio_out_pin=17,gpio_in_pin=13
+    dtoverlay=i2c-rtc,ds1307
 
-Parameters always have default values, although in some cases (e.g. "w1-gpio")
-it is necessary to provided multiple overlays in order to get the desired
-behaviour. See the list of overlays below for a description of the parameters
+This causes the file /boot/overlays/i2c-rtc.dtbo to be loaded and a "node"
+describing the DS1307 I2C device to be added to the Device Tree for the Pi. By
+default it usees address 0x68, but this can be modified with an additional DT
+parameter:
+
+    dtoverlay=i2c-rtc,ds1307,addr=0x68
+
+Parameters usually have default values, although certain parameters are
+mandatory. See the list of overlays below for a description of the parameters
 and their defaults.
 
 The Overlay and Parameter Reference
@@ -292,7 +298,9 @@ Info:   Analog Devices ADV7282M analogue video to CSI2 bridge.
         Uses Unicam1, which is the standard camera connector on most Pi
         variants.
 Load:   dtoverlay=adv7282m,<param>=<val>
-Params: i2c_pins_28_29          Use pins 28&29 for the I2C instead of 44&45.
+Params: i2c_pins_0_1            Use pins 0&1 for the I2C instead of 44&45.
+                                Useful on Compute Modules.
+        i2c_pins_28_29          Use pins 28&29 for the I2C instead of 44&45.
                                 This is required for Pi B+, 2, 0, and 0W.
         addr                    Overrides the I2C address (default 0x21)
 
@@ -301,7 +309,9 @@ Name:   adv728x-m
 Info:   Analog Devices ADV728[0|1|2]-M analogue video to CSI2 bridges.
         This is a wrapper for adv7282m, and defaults to ADV7282M.
 Load:   dtoverlay=adv728x-m,<param>=<val>
-Params: i2c_pins_28_29          Use pins 28&29 for the I2C instead of 44&45.
+Params: i2c_pins_0_1            Use pins 0&1 for the I2C instead of 44&45.
+                                Useful on Compute Modules.
+        i2c_pins_28_29          Use pins 28&29 for the I2C instead of 44&45.
                                 This is required for Pi B+, 2, 0, and 0W.
         addr                    Overrides the I2C address (default 0x21)
         adv7280m                Select ADV7280-M.
@@ -608,7 +618,7 @@ Load:   dtoverlay=gpio-ir,<param>=<val>
 Params: gpio_pin                Input pin number. Default is 18.
 
         gpio_pull               Desired pull-up/down state (off, down, up)
-                                Default is "down".
+                                Default is "up".
 
         rc-map-name             Default rc keymap (can also be changed by
                                 ir-keytable), defaults to "rc-rc6-mce"
@@ -769,6 +779,27 @@ Params: 24db_digital_gain       Allow gain to be applied via the PCM512x codec
                                 master for bit clock and frame clock.
 
 
+Name:   hifiberry-dacplusadc
+Info:   Configures the HifiBerry DAC+ADC audio card
+Load:   dtoverlay=hifiberry-dacplusadc,<param>=<val>
+Params: 24db_digital_gain       Allow gain to be applied via the PCM512x codec
+                                Digital volume control. Enable with
+                                "dtoverlay=hifiberry-dacplus,24db_digital_gain"
+                                (The default behaviour is that the Digital
+                                volume control is limited to a maximum of
+                                0dB. ie. it can attenuate but not provide
+                                gain. For most users, this will be desired
+                                as it will prevent clipping. By appending
+                                the 24dB_digital_gain parameter, the Digital
+                                volume control will allow up to 24dB of
+                                gain. If this parameter is enabled, it is the
+                                responsibility of the user to ensure that
+                                the Digital volume control is set to a value
+                                that does not result in clipping/distortion!)
+        slave                   Force DAC+ Pro into slave mode, using Pi as
+                                master for bit clock and frame clock.
+
+
 Name:   hifiberry-digi
 Info:   Configures the HifiBerry Digi and Digi+ audio card
 Load:   dtoverlay=hifiberry-digi
@@ -1138,29 +1169,8 @@ Params: <None>
 
 
 Name:   lirc-rpi
-Info:   Configures lirc-rpi (Linux Infrared Remote Control for Raspberry Pi)
-        Consult the module documentation for more details.
-Load:   dtoverlay=lirc-rpi,<param>=<val>
-Params: gpio_out_pin            GPIO for output (default "17")
-
-        gpio_in_pin             GPIO for input (default "18")
-
-        gpio_in_pull            Pull up/down/off on the input pin
-                                (default "down")
-
-        sense                   Override the IR receive auto-detection logic:
-                                 "0" = force active-high
-                                 "1" = force active-low
-                                 "-1" = use auto-detection
-                                (default "-1")
-
-        softcarrier             Turn the software carrier "on" or "off"
-                                (default "on")
-
-        invert                  "on" = invert the output pin (default "off")
-
-        debug                   "on" = enable additional debug messages
-                                (default "off")
+Info:   This overlay has been deprecated and removed - see gpio-ir
+Load:   <Deprecated>
 
 
 Name:   ltc294x
@@ -1356,7 +1366,10 @@ Info:   Omnivision OV5647 camera module.
         Uses Unicam 1, which is the standard camera connector on most Pi
         variants.
 Load:   dtoverlay=ov5647,<param>=<val>
-Params: i2c_pins_28_29          Use pins 28&29 for the I2C instead of 44&45.
+Params: i2c_pins_0_1            Use pins 0&1 for the I2C instead of 44&45.
+                                Useful on Compute Modules.
+
+        i2c_pins_28_29          Use pins 28&29 for the I2C instead of 44&45.
                                 This is required for Pi B+, 2, 0, and 0W.
 
 
@@ -2015,6 +2028,9 @@ Params: 4lane                   Use 4 lanes (only applicable to Compute Modules
                                 (574Mbit/s) and 486000000 (972Mbit/s - default)
                                 are supported by the driver.
 
+        i2c_pins_0_1            Use pins 0&1 for the I2C instead of 44&45.
+                                Useful on Compute Modules.
+
         i2c_pins_28_29          Use pins 28&29 for the I2C instead of 44&45.
                                 This is required for Pi B+, 2, 0, and 0W.