[PATCH v2 0/6] auxdisplay: Add support for the Titanmec TM1628 7 segment display controller

[PATCH v2 0/6] auxdisplay: Add support for the Titanmec TM1628 7 segment display controller

[Heiner Kallweit]

This series adds support for the Titanmec TM1628 7 segment display
controller. It's based on previous RFC work from Andreas Färber.
The RFC version placed the driver in the LED subsystem, but this was
NAK'ed by the LED maintainer. Therefore I moved the driver to
/drivers/auxdisplay what seems most reasonable to me.

To be decided is through which tree this series should go.
I'd think SPI would be most suited, but that's a decision I
leave up to the respective maintainers.

Further changes to the RFC version:
- Driver can be built also w/o LED class support, for displays that
  don't have any symbols to be exposed as LED's.
- Simplified the code and rewrote a lot of it.
- Driver is now kind of a MVP, but functionality should be sufficient
  for most use cases.
- Use the existing 7 segment support in uapi/linux/map_to_7segment.h
  as suggested by Geert Uytterhoeven.

Note: There's a number of chips from other manufacturers that are
      almost identical, e.g. FD628, SM1628. Only difference I saw so
      far is that they partially support other display modes.
      TM1628: 6x12, 7x11
      SM1628C: 4x13, 5x12, 6x11, 7x10
      For typical displays on devices using these chips this
      difference shouldn't matter.

Successfully tested on a TX3 Mini TV box that has an SM1628C and a
display with 4 digits and 7 symbols.

v2:
- (re-)add Andreas' SoB to two patches
- fix YAML issues
- include ctype.h explicitly
- add info message in probe()

Andreas Färber (2):
  spi: gpio: Implement LSB First bitbang support
  dt-bindings: vendor-prefixes: Add Titan Micro Electronics

Heiner Kallweit (4):
  dt-bindings: auxdisplay: Add Titan Micro Electronics TM1628
  docs: ABI: document tm1628 attribute display-text
  auxdisplay: add support for Titanmec TM1628 7 segment display
    controller
  arm64: dts: meson-gxl-s905w-tx3-mini: add support for the 7 segment
    display

 .../testing/sysfs-devices-auxdisplay-tm1628   |   7 +
 .../bindings/auxdisplay/titanmec,tm1628.yaml  |  88 ++++
 .../devicetree/bindings/vendor-prefixes.yaml  |   2 +
 .../dts/amlogic/meson-gxl-s905w-tx3-mini.dts  |  59 +++
 drivers/auxdisplay/Kconfig                    |  10 +
 drivers/auxdisplay/Makefile                   |   1 +
 drivers/auxdisplay/tm1628.c                   | 376 ++++++++++++++++++
 drivers/spi/spi-bitbang-txrx.h                |  66 +++
 drivers/spi/spi-gpio.c                        |  42 +-
 9 files changed, 642 insertions(+), 9 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-devices-auxdisplay-tm1628
 create mode 100644 Documentation/devicetree/bindings/auxdisplay/titanmec,tm1628.yaml
 create mode 100644 drivers/auxdisplay/tm1628.c

-- 
2.35.1

[PATCH v2 1/6] spi: gpio: Implement LSB First bitbang support

[Heiner Kallweit]

From: Andreas Färber <afaerber@suse.de>

Add support for slave DT property spi-lsb-first, i.e., SPI_LSB_FIRST mode.
Duplicate the inline helpers bitbang_txrx_be_cpha{0,1} as LE versions.
Conditionally call them from all the spi-gpio txrx_word callbacks.

Some alternatives to this implementation approach were discussed back
then [0], but eventually it was considered reasonable.

[0] https://lore.kernel.org/linux-arm-kernel/20191212033952.5967-8-afaerber@suse.de/

Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/spi/spi-bitbang-txrx.h | 66 ++++++++++++++++++++++++++++++++++
 drivers/spi/spi-gpio.c         | 42 +++++++++++++++++-----
 2 files changed, 99 insertions(+), 9 deletions(-)

diff --git a/drivers/spi/spi-bitbang-txrx.h b/drivers/spi/spi-bitbang-txrx.h
index ae61d72c7..267342dfa 100644
--- a/drivers/spi/spi-bitbang-txrx.h
+++ b/drivers/spi/spi-bitbang-txrx.h
@@ -41,6 +41,8 @@
  * chips need ... there may be several reasons you'd need to tweak timings
  * in these routines, not just to make it faster or slower to match a
  * particular CPU clock rate.
+ *
+ * ToDo: Maybe the bitrev macros can be used to improve the code?
  */
 
 static inline u32
@@ -106,3 +108,67 @@ bitbang_txrx_be_cpha1(struct spi_device *spi,
 	}
 	return word;
 }
+
+static inline u32
+bitbang_txrx_le_cpha0(struct spi_device *spi,
+		unsigned int nsecs, unsigned int cpol, unsigned int flags,
+		u32 word, u8 bits)
+{
+	/* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */
+
+	u32 oldbit = !(word & 1);
+	/* clock starts at inactive polarity */
+	for (; likely(bits); bits--) {
+
+		/* setup LSB (to slave) on trailing edge */
+		if ((flags & SPI_MASTER_NO_TX) == 0) {
+			if ((word & 1) != oldbit) {
+				setmosi(spi, word & 1);
+				oldbit = word & 1;
+			}
+		}
+		spidelay(nsecs);	/* T(setup) */
+
+		setsck(spi, !cpol);
+		spidelay(nsecs);
+
+		/* sample LSB (from slave) on leading edge */
+		word >>= 1;
+		if ((flags & SPI_MASTER_NO_RX) == 0)
+			word |= getmiso(spi) << (bits - 1);
+		setsck(spi, cpol);
+	}
+	return word;
+}
+
+static inline u32
+bitbang_txrx_le_cpha1(struct spi_device *spi,
+		unsigned int nsecs, unsigned int cpol, unsigned int flags,
+		u32 word, u8 bits)
+{
+	/* if (cpol == 0) this is SPI_MODE_1; else this is SPI_MODE_3 */
+
+	u32 oldbit = !(word & 1);
+	/* clock starts at inactive polarity */
+	for (; likely(bits); bits--) {
+
+		/* setup LSB (to slave) on leading edge */
+		setsck(spi, !cpol);
+		if ((flags & SPI_MASTER_NO_TX) == 0) {
+			if ((word & 1) != oldbit) {
+				setmosi(spi, word & 1);
+				oldbit = word & 1;
+			}
+		}
+		spidelay(nsecs); /* T(setup) */
+
+		setsck(spi, cpol);
+		spidelay(nsecs);
+
+		/* sample LSB (from slave) on trailing edge */
+		word >>= 1;
+		if ((flags & SPI_MASTER_NO_RX) == 0)
+			word |= getmiso(spi) << (bits - 1);
+	}
+	return word;
+}
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index 0584f4d2f..4b12c4964 100644
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -135,25 +135,37 @@ static inline int getmiso(const struct spi_device *spi)
 static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
-	return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha0(spi, nsecs, 0, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
 }
 
 static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
-	return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha1(spi, nsecs, 0, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);
 }
 
 static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
-	return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha0(spi, nsecs, 1, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);
 }
 
 static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
-	return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha1(spi, nsecs, 1, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);
 }
 
 /*
@@ -170,28 +182,40 @@ static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
 	flags = spi->master->flags;
-	return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha0(spi, nsecs, 0, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
 }
 
 static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
 	flags = spi->master->flags;
-	return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha1(spi, nsecs, 0, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);
 }
 
 static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
 	flags = spi->master->flags;
-	return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha0(spi, nsecs, 1, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);
 }
 
 static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
 	flags = spi->master->flags;
-	return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha1(spi, nsecs, 1, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);
 }
 
 /*----------------------------------------------------------------------*/
@@ -378,7 +402,7 @@ static int spi_gpio_probe(struct platform_device *pdev)
 
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
 	master->mode_bits = SPI_3WIRE | SPI_3WIRE_HIZ | SPI_CPHA | SPI_CPOL |
-			    SPI_CS_HIGH;
+			    SPI_CS_HIGH | SPI_LSB_FIRST;
 	if (!spi_gpio->mosi) {
 		/* HW configuration without MOSI pin
 		 *
-- 
2.35.1

[PATCH v2 2/6] dt-bindings: vendor-prefixes: Add Titan Micro Electronics

[Heiner Kallweit]

From: Andreas Färber <afaerber@suse.de>

Assign vendor prefix "titanmec", matching their domain name.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 Documentation/devicetree/bindings/vendor-prefixes.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/vendor-prefixes.yaml b/Documentation/devicetree/bindings/vendor-prefixes.yaml
index ebe294516..38bfb462c 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.yaml
+++ b/Documentation/devicetree/bindings/vendor-prefixes.yaml
@@ -1229,6 +1229,8 @@ patternProperties:
     description: Texas Instruments
   "^tianma,.*":
     description: Tianma Micro-electronics Co., Ltd.
+  "^titanmec,.*":
+    description: Shenzhen Titan Micro Electronics Co., Ltd.
   "^tlm,.*":
     description: Trusted Logic Mobility
   "^tmt,.*":
-- 
2.35.1

[PATCH v2 3/6] dt-bindings: auxdisplay: Add Titan Micro Electronics TM1628

[Heiner Kallweit]

Add a YAML schema binding for TM1628 auxdisplay
(7/11-segment LED) controller.

This patch is partially based on previous RFC work from
Andreas Färber <afaerber@suse.de>.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- (re-)add Andreas' SoB
- fix YAML errors reported by Rob
---
 .../bindings/auxdisplay/titanmec,tm1628.yaml  | 88 +++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/auxdisplay/titanmec,tm1628.yaml

diff --git a/Documentation/devicetree/bindings/auxdisplay/titanmec,tm1628.yaml b/Documentation/devicetree/bindings/auxdisplay/titanmec,tm1628.yaml
new file mode 100644
index 000000000..da7cc16e7
--- /dev/null
+++ b/Documentation/devicetree/bindings/auxdisplay/titanmec,tm1628.yaml
@@ -0,0 +1,88 @@
+# SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/auxdisplay/titanmec,tm1628.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Titan Micro Electronics TM1628 LED controller
+
+maintainers:
+  - Andreas Färber <afaerber@suse.de>
+  - Heiner Kallweit <hkallweit1@gmail.com>
+
+properties:
+  compatible:
+    enum:
+      - titanmec,tm1628
+
+  reg:
+    maxItems: 1
+
+  grid:
+    description:
+      Mapping of display digit position to grid number.
+      This implicitly defines the display size.
+    $ref: /schemas/types.yaml#/definitions/uint8-array
+    minItems: 1
+    maxItems: 7
+
+  segment-mapping:
+    description:
+      Mapping of 7 segment display segments A-G to bit numbers 1-12.
+    $ref: /schemas/types.yaml#/definitions/uint8-array
+    minItems: 7
+    maxItems: 7
+
+  "#address-cells":
+    const: 2
+
+  "#size-cells":
+    const: 0
+
+required:
+  - compatible
+  - reg
+
+patternProperties:
+  "^.*@[1-7],([1-9]|1[0-6])$":
+    type: object
+    description: |
+      Properties for a single LED.
+
+    properties:
+      reg:
+        description: |
+          1-based grid number, followed by 1-based segment bit number.
+        maxItems: 1
+
+    required:
+      - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/leds/common.h>
+
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        led-controller@0 {
+            compatible = "titanmec,tm1628";
+            reg = <0>;
+            spi-3-wire;
+            spi-lsb-first;
+            spi-max-frequency = <500000>;
+            grid = /bits/ 8 <4 3 2 1>;
+            segment-mapping = /bits/ 8 <4 5 6 1 2 3 7>;
+            #address-cells = <2>;
+            #size-cells = <0>;
+
+            alarmn@5,4 {
+                reg = <5 4>;
+                function = LED_FUNCTION_ALARM;
+            };
+        };
+    };
+...
-- 
2.35.1

[PATCH v2 4/6] docs: ABI: document tm1628 attribute display-text

[Heiner Kallweit]

Document the attribute for reading / writing the text to be displayed on
the 7 segment display.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 Documentation/ABI/testing/sysfs-devices-auxdisplay-tm1628 | 7 +++++++
 1 file changed, 7 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-devices-auxdisplay-tm1628

diff --git a/Documentation/ABI/testing/sysfs-devices-auxdisplay-tm1628 b/Documentation/ABI/testing/sysfs-devices-auxdisplay-tm1628
new file mode 100644
index 000000000..382757e72
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-auxdisplay-tm1628
@@ -0,0 +1,7 @@
+What:		/sys/devices/.../display-text
+Date:		February 2022
+Contact:	Heiner Kallweit <hkallweit1@gmail.com>
+Description:
+		The text to be displayed on the 7 segment display.
+		Any printable character is allowed as input, but some
+		can not be displayed in a readable way with 7 segments.
-- 
2.35.1

[PATCH v2 5/6] auxdisplay: add support for Titanmec TM1628 7 segment display controller

[Heiner Kallweit]

This patch adds support for the Titanmec TM1628 7 segment display
controller. It's based on previous RFC work from Andreas Färber.
The RFC version placed the driver in the LED subsystem, but this was
NAK'ed by the LED maintainer. Therefore I moved the driver to
/drivers/auxdisplay what seems most reasonable to me.

Further changes to the RFC version:
- Driver can be built also w/o LED class support, for displays that
  don't have any symbols to be exposed as LED's.
- Simplified the code and rewrote a lot of it.
- Driver is now kind of a MVP, but functionality should be sufficient
  for most use cases.
- Use the existing 7 segment support in uapi/linux/map_to_7segment.h
  as suggested by Geert Uytterhoeven.

Note: There's a number of chips from other manufacturers that are
      almost identical, e.g. FD628, SM1628. Only difference I saw so
      far is that they partially support other display modes.
      TM1628: 6x12, 7x11
      SM1628C: 4x13, 5x12, 6x11, 7x10
      For typical displays on devices using these chips this
      difference shouldn't matter.

Successfully tested on a TX3 Mini TV box that has an SM1628C and a
display with 4 digits and 7 symbols.

Tested-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- include ctype.h explicitly
- add info message in probe()
- (re-)add Andreas' SoB
---
 drivers/auxdisplay/Kconfig  |  10 +
 drivers/auxdisplay/Makefile |   1 +
 drivers/auxdisplay/tm1628.c | 376 ++++++++++++++++++++++++++++++++++++
 3 files changed, 387 insertions(+)
 create mode 100644 drivers/auxdisplay/tm1628.c

diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig
index 64012cda4..25ef2e452 100644
--- a/drivers/auxdisplay/Kconfig
+++ b/drivers/auxdisplay/Kconfig
@@ -203,6 +203,16 @@ config ARM_CHARLCD
 	  line and the Linux version on the second line, but that's
 	  still useful.
 
+config TM1628
+	tristate "TM1628 driver for LED 7/11 segment displays"
+	depends on SPI
+	depends on OF || COMPILE_TEST
+	help
+	  Say Y to enable support for Titan Micro Electronics TM1628
+	  LED controller.
+	  It's a 3-wire SPI device controlling a two-dimensional grid of
+	  LEDs. Dimming is applied to all outputs through an internal PWM.
+
 menuconfig PARPORT_PANEL
 	tristate "Parallel port LCD/Keypad Panel support"
 	depends on PARPORT
diff --git a/drivers/auxdisplay/Makefile b/drivers/auxdisplay/Makefile
index 6968ed4d3..7728e17e1 100644
--- a/drivers/auxdisplay/Makefile
+++ b/drivers/auxdisplay/Makefile
@@ -14,3 +14,4 @@ obj-$(CONFIG_HT16K33)		+= ht16k33.o
 obj-$(CONFIG_PARPORT_PANEL)	+= panel.o
 obj-$(CONFIG_LCD2S)		+= lcd2s.o
 obj-$(CONFIG_LINEDISP)		+= line-display.o
+obj-$(CONFIG_TM1628)		+= tm1628.o
diff --git a/drivers/auxdisplay/tm1628.c b/drivers/auxdisplay/tm1628.c
new file mode 100644
index 000000000..b802b5c30
--- /dev/null
+++ b/drivers/auxdisplay/tm1628.c
@@ -0,0 +1,376 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Titan Micro Electronics TM1628 LED controller
+ *
+ * Copyright (c) 2019 Andreas Färber
+ */
+
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/spi/spi.h>
+#include <uapi/linux/map_to_7segment.h>
+
+#define TM1628_CMD_DISPLAY_MODE		(0 << 6)
+#define TM1628_DISPLAY_MODE_6_12	0x02
+#define TM1628_DISPLAY_MODE_7_11	0x03
+
+#define TM1628_CMD_DATA			(1 << 6)
+#define TM1628_DATA_TEST_MODE		BIT(3)
+#define TM1628_DATA_FIXED_ADDR		BIT(2)
+#define TM1628_DATA_WRITE_DATA		0x00
+#define TM1628_DATA_READ_DATA		0x02
+
+#define TM1628_CMD_DISPLAY_CTRL		(2 << 6)
+#define TM1628_DISPLAY_CTRL_DISPLAY_ON	BIT(3)
+
+#define TM1628_CMD_SET_ADDRESS		(3 << 6)
+
+#define TM1628_BRIGHTNESS_MAX		7
+
+/* Physical limits, depending on the mode the chip may support less */
+#define MAX_GRID_SIZE			7
+#define MAX_SEGMENT_NUM			16
+
+struct tm1628_led {
+	struct led_classdev	leddev;
+	struct tm1628		*ctrl;
+	u32			grid;
+	u32			seg;
+};
+
+struct tm1628 {
+	struct spi_device		*spi;
+	__le16				data[MAX_GRID_SIZE];
+	struct mutex			disp_lock;
+	char				text[MAX_GRID_SIZE + 1];
+	u8				segment_mapping[7];
+	u8				grid[MAX_GRID_SIZE];
+	int				grid_size;
+	struct tm1628_led		leds[];
+};
+
+/* Command 1: Display Mode Setting */
+static int tm1628_set_display_mode(struct spi_device *spi, u8 grid_mode)
+{
+	u8 cmd = TM1628_CMD_DISPLAY_MODE | grid_mode;
+
+	return spi_write(spi, &cmd, 1);
+}
+
+/* Command 3: Address Setting */
+static int tm1628_set_address(struct spi_device *spi, u8 offset)
+{
+	u8 cmd = TM1628_CMD_SET_ADDRESS | (offset * sizeof(__le16));
+
+	return spi_write(spi, &cmd, 1);
+}
+
+/* Command 2: Data Setting */
+static int tm1628_write_data(struct spi_device *spi, unsigned int offset,
+			     unsigned int len)
+{
+	struct tm1628 *s = spi_get_drvdata(spi);
+	u8 cmd = TM1628_CMD_DATA | TM1628_DATA_WRITE_DATA;
+	struct spi_transfer xfers[] = {
+		{
+			.tx_buf = &cmd,
+			.len = 1,
+		},
+		{
+			.tx_buf = (__force void *)(s->data + offset),
+			.len = len * sizeof(__le16),
+		},
+	};
+
+	if (offset + len > MAX_GRID_SIZE) {
+		dev_err(&spi->dev, "Invalid data address offset %u len %u\n",
+			offset, len);
+		return -EINVAL;
+	}
+
+	tm1628_set_address(spi, offset);
+
+	return spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers));
+}
+
+/* Command 4: Display Control */
+static int tm1628_set_display_ctrl(struct spi_device *spi, bool on)
+{
+	u8 cmd = TM1628_CMD_DISPLAY_CTRL | TM1628_BRIGHTNESS_MAX;
+
+	if (on)
+		cmd |= TM1628_DISPLAY_CTRL_DISPLAY_ON;
+
+	return spi_write(spi, &cmd, 1);
+}
+
+static int tm1628_show_text(struct tm1628 *s)
+{
+	static SEG7_CONVERSION_MAP(map_seg7, MAP_ASCII7SEG_ALPHANUM);
+	int i, ret;
+
+	int msg_len = strlen(s->text);
+
+	mutex_lock(&s->disp_lock);
+
+	for (i = 0; i < s->grid_size; i++) {
+		int pos = s->grid[i] - 1;
+
+		if (i < msg_len) {
+			int char7_raw = map_to_seg7(&map_seg7, s->text[i]);
+			int j, char7;
+
+			for (j = 0, char7 = 0; j < 7; j++) {
+				if (char7_raw & BIT(j))
+					char7 |= BIT(s->segment_mapping[j] - 1);
+			}
+
+			s->data[pos] = cpu_to_le16(char7);
+		} else {
+			s->data[pos] = 0;
+		}
+	}
+
+	ret = tm1628_write_data(s->spi, 0, s->grid_size);
+
+	mutex_unlock(&s->disp_lock);
+
+	return ret;
+}
+
+static int tm1628_led_set_brightness(struct led_classdev *led_cdev,
+				     enum led_brightness brightness)
+{
+	struct tm1628_led *led = container_of(led_cdev, struct tm1628_led, leddev);
+	struct tm1628 *s = led->ctrl;
+	int offset, ret;
+	__le16 bit;
+
+	offset = led->grid - 1;
+	bit = cpu_to_le16(BIT(led->seg - 1));
+
+	mutex_lock(&s->disp_lock);
+
+	if (brightness == LED_OFF)
+		s->data[offset] &= ~bit;
+	else
+		s->data[offset] |= bit;
+
+	ret = tm1628_write_data(s->spi, offset, 1);
+
+	mutex_unlock(&s->disp_lock);
+
+	return ret;
+}
+
+static enum led_brightness tm1628_led_get_brightness(struct led_classdev *led_cdev)
+{
+	struct tm1628_led *led = container_of(led_cdev, struct tm1628_led, leddev);
+	struct tm1628 *s = led->ctrl;
+	int offset;
+	__le16 bit;
+	bool on;
+
+	offset = led->grid - 1;
+	bit = cpu_to_le16(BIT(led->seg - 1));
+
+	mutex_lock(&s->disp_lock);
+	on = s->data[offset] & bit;
+	mutex_unlock(&s->disp_lock);
+
+	return on ? LED_ON : LED_OFF;
+}
+
+static int tm1628_register_led(struct tm1628 *s, struct fwnode_handle *node,
+			       u32 grid, u32 seg, struct tm1628_led *led)
+{
+	struct device *dev = &s->spi->dev;
+	struct led_init_data init_data = { .fwnode = node };
+
+	led->ctrl = s;
+	led->grid = grid;
+	led->seg  = seg;
+	led->leddev.max_brightness = LED_ON;
+	led->leddev.brightness_set_blocking = tm1628_led_set_brightness;
+	led->leddev.brightness_get = tm1628_led_get_brightness;
+
+	return devm_led_classdev_register_ext(dev, &led->leddev, &init_data);
+}
+
+static ssize_t display_text_show(struct device *dev, struct device_attribute *attr,
+				 char *buf)
+{
+	struct tm1628 *s = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%s\n", s->text);
+}
+
+static ssize_t display_text_store(struct device *dev, struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	struct tm1628 *s = dev_get_drvdata(dev);
+	int ret, i;
+
+	if (count > s->grid_size + 1) /* consider trailing newline */
+		return -E2BIG;
+
+	for (i = 0; i < count && isprint(buf[i]); i++)
+		s->text[i] = buf[i];
+
+	s->text[i] = '\0';
+
+	ret = tm1628_show_text(s);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static const DEVICE_ATTR_RW(display_text);
+
+static int tm1628_spi_probe(struct spi_device *spi)
+{
+	struct fwnode_handle *child;
+	unsigned int num_leds;
+	struct tm1628 *s;
+	int ret, i;
+
+	num_leds = device_get_child_node_count(&spi->dev);
+
+	s = devm_kzalloc(&spi->dev, struct_size(s, leds, num_leds), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	s->spi = spi;
+	spi_set_drvdata(spi, s);
+
+	mutex_init(&s->disp_lock);
+
+	msleep(200); /* according to TM1628 datasheet */
+
+	/* clear screen */
+	ret = tm1628_write_data(spi, 0, MAX_GRID_SIZE);
+	if (ret)
+		return ret;
+	/* Assume that subsequent SPI transfers will be ok if first was ok */
+
+	/* For now we support 6x12 mode only. This should be sufficient for most use cases */
+	tm1628_set_display_mode(spi, TM1628_DISPLAY_MODE_6_12);
+
+	tm1628_set_display_ctrl(spi, true);
+
+	if (!IS_REACHABLE(CONFIG_LEDS_CLASS))
+		goto no_leds;
+
+	num_leds = 0;
+
+	device_for_each_child_node(&spi->dev, child) {
+		u32 reg[2];
+
+		ret = fwnode_property_read_u32_array(child, "reg", reg, 2);
+		if (ret) {
+			dev_err(&spi->dev, "Reading %s reg property failed (%d)\n",
+				fwnode_get_name(child), ret);
+			continue;
+		}
+
+		if (reg[0] == 0 || reg[0] > MAX_GRID_SIZE) {
+			dev_err(&spi->dev, "Invalid grid %u at %s\n",
+				reg[0], fwnode_get_name(child));
+			continue;
+		}
+
+		if (reg[1] == 0 || reg[1] > MAX_SEGMENT_NUM) {
+			dev_err(&spi->dev, "Invalid segment %u at %s\n",
+				reg[1], fwnode_get_name(child));
+			continue;
+		}
+
+		ret = tm1628_register_led(s, child, reg[0], reg[1], s->leds + num_leds);
+		if (ret) {
+			dev_err(&spi->dev, "Failed to register LED %s (%d)\n",
+				fwnode_get_name(child), ret);
+			continue;
+		}
+		num_leds++;
+	}
+
+no_leds:
+	ret = device_property_count_u8(&spi->dev, "grid");
+	if (ret < 1 || ret > MAX_GRID_SIZE) {
+		dev_err(&spi->dev, "Invalid display length (%d)\n", ret);
+		return -EINVAL;
+	}
+
+	s->grid_size = ret;
+
+	ret = device_property_read_u8_array(&spi->dev, "grid", s->grid, s->grid_size);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < s->grid_size; i++) {
+		if (s->grid[i] < 1 || s->grid[i] > s->grid_size)
+			return -EINVAL;
+	}
+
+	ret = device_property_read_u8_array(&spi->dev, "segment-mapping", s->segment_mapping, 7);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < 7; i++) {
+		if (s->segment_mapping[i] < 1 || s->segment_mapping[i] > MAX_SEGMENT_NUM)
+			return -EINVAL;
+	}
+
+	ret = device_create_file(&spi->dev, &dev_attr_display_text);
+	if (ret)
+		return ret;
+
+	dev_info(&spi->dev, "Configured display with %u digits and %u symbols\n",
+		 s->grid_size, num_leds);
+
+	return 0;
+}
+
+static void tm1628_spi_remove(struct spi_device *spi)
+{
+	device_remove_file(&spi->dev, &dev_attr_display_text);
+	tm1628_set_display_ctrl(spi, false);
+}
+
+static void tm1628_spi_shutdown(struct spi_device *spi)
+{
+	tm1628_set_display_ctrl(spi, false);
+}
+
+static const struct of_device_id tm1628_spi_of_matches[] = {
+	{ .compatible = "titanmec,tm1628" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, tm1628_spi_of_matches);
+
+static const struct spi_device_id tm1628_spi_id_table[] = {
+	{ "tm1628" },
+	{},
+};
+MODULE_DEVICE_TABLE(spi, tm1628_spi_id_table);
+
+static struct spi_driver tm1628_spi_driver = {
+	.probe = tm1628_spi_probe,
+	.remove = tm1628_spi_remove,
+	.shutdown = tm1628_spi_shutdown,
+	.id_table = tm1628_spi_id_table,
+
+	.driver = {
+		.name = "tm1628",
+		.of_match_table = tm1628_spi_of_matches,
+	},
+};
+module_spi_driver(tm1628_spi_driver);
+
+MODULE_DESCRIPTION("TM1628 LED controller driver");
+MODULE_AUTHOR("Andreas Färber");
+MODULE_LICENSE("GPL");
-- 
2.35.1

[PATCH v2 6/6] arm64: dts: meson-gxl-s905w-tx3-mini: add support for the 7 segment display

[Heiner Kallweit]

This patch adds support for the 7 segment display of the device.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 .../dts/amlogic/meson-gxl-s905w-tx3-mini.dts  | 59 +++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-gxl-s905w-tx3-mini.dts b/arch/arm64/boot/dts/amlogic/meson-gxl-s905w-tx3-mini.dts
index 6705c2082..20bbd931e 100644
--- a/arch/arm64/boot/dts/amlogic/meson-gxl-s905w-tx3-mini.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-gxl-s905w-tx3-mini.dts
@@ -10,6 +10,7 @@
 
 #include "meson-gxl-s905x.dtsi"
 #include "meson-gx-p23x-q20x.dtsi"
+#include <dt-bindings/leds/common.h>
 
 / {
 	compatible = "oranth,tx3-mini", "amlogic,s905w", "amlogic,meson-gxl";
@@ -19,6 +20,64 @@ memory@0 {
 		device_type = "memory";
 		reg = <0x0 0x0 0x0 0x40000000>; /* 1 GiB or 2 GiB */
 	};
+
+	spi {
+		compatible = "spi-gpio";
+		sck-gpios = <&gpio GPIODV_27  GPIO_ACTIVE_HIGH>;
+		mosi-gpios = <&gpio GPIODV_26 GPIO_ACTIVE_HIGH>;
+		cs-gpios = <&gpio_ao GPIOAO_4 GPIO_ACTIVE_LOW>;
+		num-chipselects = <1>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		tm1628: led-controller@0 {
+			compatible = "titanmec,tm1628";
+			reg = <0>;
+			spi-3wire;
+			spi-lsb-first;
+			spi-rx-delay-us = <1>;
+			spi-max-frequency = <500000>;
+			#address-cells = <2>;
+			#size-cells = <0>;
+
+			segment-mapping = /bits/ 8 <4 5 6 1 2 3 7>;
+			grid = /bits/ 8 <4 3 2 1>;
+
+			alarm@5,1 {
+				reg = <5 1>;
+				function = LED_FUNCTION_ALARM;
+			};
+
+			usb@5,2 {
+				reg = <5 2>;
+				function = LED_FUNCTION_USB;
+			};
+			play@5,3 {
+				reg = <5 3>;
+				function = "play";
+			};
+
+			pause@5,4 {
+				reg = <5 4>;
+				function = "pause";
+			};
+
+			colon@5,5 {
+				reg = <5 5>;
+				function = "colon";
+			};
+
+			lan@5,6 {
+				reg = <5 6>;
+				function = LED_FUNCTION_LAN;
+			};
+
+			wlan@5,7 {
+				reg = <5 7>;
+				function = LED_FUNCTION_WLAN;
+			};
+		};
+	};
 };
 
 &ir {
-- 
2.35.1

Re: [PATCH v2 0/6] auxdisplay: Add support for the Titanmec TM1628 7 segment display controller

[Miguel Ojeda]

On Mon, Feb 21, 2022 at 9:19 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
>
> v2:
> - (re-)add Andreas' SoB to two patches

But those were also developed by you too, right? i.e. it should have a
Co-developed-by too, otherwise it looks like you only handled the
patch:

```
Example of a patch submitted by the From: author::

        <changelog>

        Co-developed-by: First Co-Author <first@coauthor.example.org>
        Signed-off-by: First Co-Author <first@coauthor.example.org>
        Co-developed-by: Second Co-Author <second@coauthor.example.org>
        Signed-off-by: Second Co-Author <second@coauthor.example.org>
        Signed-off-by: From Author <from@author.example.org>
```

Cheers,
Miguel

Re: [PATCH v2 0/6] auxdisplay: Add support for the Titanmec TM1628 7 segment display controller

[Heiner Kallweit]

On 21.02.2022 23:10, Miguel Ojeda wrote:
> On Mon, Feb 21, 2022 at 9:19 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
>>
>> v2:
>> - (re-)add Andreas' SoB to two patches
> 
> But those were also developed by you too, right? i.e. it should have a
> Co-developed-by too, otherwise it looks like you only handled the
> patch:
> 

Right, about half of the original code was reworked. Let's see whether and
which feedback comes for v2. If a v3 should be needed, I'll follow your
suggestion.

> ```
> Example of a patch submitted by the From: author::
> 
>         <changelog>
> 
>         Co-developed-by: First Co-Author <first@coauthor.example.org>
>         Signed-off-by: First Co-Author <first@coauthor.example.org>
>         Co-developed-by: Second Co-Author <second@coauthor.example.org>
>         Signed-off-by: Second Co-Author <second@coauthor.example.org>
>         Signed-off-by: From Author <from@author.example.org>
> ```
> 
> Cheers,
> Miguel

Heiner

Re: [PATCH v2 5/6] auxdisplay: add support for Titanmec TM1628 7 segment display controller

[Geert Uytterhoeven]

Hi Heiner,

On Mon, Feb 21, 2022 at 9:26 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
> This patch adds support for the Titanmec TM1628 7 segment display
> controller. It's based on previous RFC work from Andreas Färber.
> The RFC version placed the driver in the LED subsystem, but this was
> NAK'ed by the LED maintainer. Therefore I moved the driver to
> /drivers/auxdisplay what seems most reasonable to me.
>
> Further changes to the RFC version:
> - Driver can be built also w/o LED class support, for displays that
>   don't have any symbols to be exposed as LED's.
> - Simplified the code and rewrote a lot of it.
> - Driver is now kind of a MVP, but functionality should be sufficient
>   for most use cases.
> - Use the existing 7 segment support in uapi/linux/map_to_7segment.h
>   as suggested by Geert Uytterhoeven.
>
> Note: There's a number of chips from other manufacturers that are
>       almost identical, e.g. FD628, SM1628. Only difference I saw so
>       far is that they partially support other display modes.
>       TM1628: 6x12, 7x11
>       SM1628C: 4x13, 5x12, 6x11, 7x10
>       For typical displays on devices using these chips this
>       difference shouldn't matter.
>
> Successfully tested on a TX3 Mini TV box that has an SM1628C and a
> display with 4 digits and 7 symbols.
>
> Tested-by: Christian Hewitt <christianshewitt@gmail.com>
> Signed-off-by: Andreas Färber <afaerber@suse.de>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>

Thanks for your patch!

> --- /dev/null
> +++ b/drivers/auxdisplay/tm1628.c

> +static int tm1628_show_text(struct tm1628 *s)
> +{
> +       static SEG7_CONVERSION_MAP(map_seg7, MAP_ASCII7SEG_ALPHANUM);

This mapping can not be overridden by the user.  Is there any
specific reason you didn't make the mapping configurable from sysfs,
cfr. map_seg7_{show,store}() in include/uapi/linux/map_to_7segment.h?

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

Re: [PATCH v2 4/6] docs: ABI: document tm1628 attribute display-text

[Geert Uytterhoeven]

Hi Heiner,

On Mon, Feb 21, 2022 at 9:26 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
> Document the attribute for reading / writing the text to be displayed on
> the 7 segment display.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>

Thanks for your patch!

> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-devices-auxdisplay-tm1628
> @@ -0,0 +1,7 @@
> +What:          /sys/devices/.../display-text
> +Date:          February 2022
> +Contact:       Heiner Kallweit <hkallweit1@gmail.com>
> +Description:
> +               The text to be displayed on the 7 segment display.
> +               Any printable character is allowed as input, but some
> +               can not be displayed in a readable way with 7 segments.

Hence you may want to make the mapping configurable, cfr.
MAP_TO_SEG7_SYSFS_FILE in include/uapi/linux/map_to_7segment.h?

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

Re: [PATCH v2 5/6] auxdisplay: add support for Titanmec TM1628 7 segment display controller

[Heiner Kallweit]

On 22.02.2022 09:19, Geert Uytterhoeven wrote:
> Hi Heiner,
> 
> On Mon, Feb 21, 2022 at 9:26 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
>> This patch adds support for the Titanmec TM1628 7 segment display
>> controller. It's based on previous RFC work from Andreas Färber.
>> The RFC version placed the driver in the LED subsystem, but this was
>> NAK'ed by the LED maintainer. Therefore I moved the driver to
>> /drivers/auxdisplay what seems most reasonable to me.
>>
>> Further changes to the RFC version:
>> - Driver can be built also w/o LED class support, for displays that
>>   don't have any symbols to be exposed as LED's.
>> - Simplified the code and rewrote a lot of it.
>> - Driver is now kind of a MVP, but functionality should be sufficient
>>   for most use cases.
>> - Use the existing 7 segment support in uapi/linux/map_to_7segment.h
>>   as suggested by Geert Uytterhoeven.
>>
>> Note: There's a number of chips from other manufacturers that are
>>       almost identical, e.g. FD628, SM1628. Only difference I saw so
>>       far is that they partially support other display modes.
>>       TM1628: 6x12, 7x11
>>       SM1628C: 4x13, 5x12, 6x11, 7x10
>>       For typical displays on devices using these chips this
>>       difference shouldn't matter.
>>
>> Successfully tested on a TX3 Mini TV box that has an SM1628C and a
>> display with 4 digits and 7 symbols.
>>
>> Tested-by: Christian Hewitt <christianshewitt@gmail.com>
>> Signed-off-by: Andreas Färber <afaerber@suse.de>
>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> 
> Thanks for your patch!
> 
>> --- /dev/null
>> +++ b/drivers/auxdisplay/tm1628.c
> 
>> +static int tm1628_show_text(struct tm1628 *s)
>> +{
>> +       static SEG7_CONVERSION_MAP(map_seg7, MAP_ASCII7SEG_ALPHANUM);
> 
> This mapping can not be overridden by the user.  Is there any
> specific reason you didn't make the mapping configurable from sysfs,
> cfr. map_seg7_{show,store}() in include/uapi/linux/map_to_7segment.h?
> 

The more features an initial driver version includes, the more discussion
topics pop up and make it less likely that we end up with at least something.
I think there's a reason why the driver was resting since the initial
attempt 2 yrs ago. Therefore I'd like to keep it as a MVP. 
If somebody should have the need for add-on features, then they can be
added later.

> Gr{oetje,eeting}s,
> 
>                         Geert
> 

Heiner

> --
> 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

Re: [PATCH v2 5/6] auxdisplay: add support for Titanmec TM1628 7 segment display controller

[Andreas Färber]

On 22.02.22 10:44, Heiner Kallweit wrote:
> On 22.02.2022 09:19, Geert Uytterhoeven wrote:
>> Hi Heiner,
>>
>> On Mon, Feb 21, 2022 at 9:26 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
>>> This patch adds support for the Titanmec TM1628 7 segment display
>>> controller. It's based on previous RFC work from Andreas Färber.
>>> The RFC version placed the driver in the LED subsystem, but this was
>>> NAK'ed by the LED maintainer. Therefore I moved the driver to
>>> /drivers/auxdisplay what seems most reasonable to me.
>>>
>>> Further changes to the RFC version:
>>> - Driver can be built also w/o LED class support, for displays that
>>>   don't have any symbols to be exposed as LED's.
>>> - Simplified the code and rewrote a lot of it.
>>> - Driver is now kind of a MVP, but functionality should be sufficient
>>>   for most use cases.
>>> - Use the existing 7 segment support in uapi/linux/map_to_7segment.h
>>>   as suggested by Geert Uytterhoeven.
>>>
>>> Note: There's a number of chips from other manufacturers that are
>>>       almost identical, e.g. FD628, SM1628. Only difference I saw so
>>>       far is that they partially support other display modes.
>>>       TM1628: 6x12, 7x11
>>>       SM1628C: 4x13, 5x12, 6x11, 7x10
>>>       For typical displays on devices using these chips this
>>>       difference shouldn't matter.
>>>
>>> Successfully tested on a TX3 Mini TV box that has an SM1628C and a
>>> display with 4 digits and 7 symbols.
>>>
>>> Tested-by: Christian Hewitt <christianshewitt@gmail.com>
>>> Signed-off-by: Andreas Färber <afaerber@suse.de>
>>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>>
>> Thanks for your patch!
>>
>>> --- /dev/null
>>> +++ b/drivers/auxdisplay/tm1628.c
>>
>>> +static int tm1628_show_text(struct tm1628 *s)
>>> +{
>>> +       static SEG7_CONVERSION_MAP(map_seg7, MAP_ASCII7SEG_ALPHANUM);
>>
>> This mapping can not be overridden by the user.  Is there any
>> specific reason you didn't make the mapping configurable from sysfs,
>> cfr. map_seg7_{show,store}() in include/uapi/linux/map_to_7segment.h?
>>
> 
> The more features an initial driver version includes, the more discussion
> topics pop up and make it less likely that we end up with at least something.
> I think there's a reason why the driver was resting since the initial
> attempt 2 yrs ago. Therefore I'd like to keep it as a MVP. 
> If somebody should have the need for add-on features, then they can be
> added later.

As I pointed out in your v1, I did implement all that already, as was
requested by Geert on my RFC:

https://github.com/afaerber/linux/commit/bbecf951348c7de8ba922c6c002a09369b717d82

Regards,
Andreas

-- 
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Ivo Totev
HRB 36809 (AG Nürnberg)

Re: [PATCH v2 0/6] auxdisplay: Add support for the Titanmec TM1628 7 segment display controller

[Andreas Färber]

On 21.02.22 23:57, Heiner Kallweit wrote:
> On 21.02.2022 23:10, Miguel Ojeda wrote:
>> On Mon, Feb 21, 2022 at 9:19 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
>>>
>>> v2:
>>> - (re-)add Andreas' SoB to two patches
>>
>> But those were also developed by you too, right? i.e. it should have a
>> Co-developed-by too, otherwise it looks like you only handled the
>> patch:
>>
> 
> Right, about half of the original code was reworked. Let's see whether and
> which feedback comes for v2. If a v3 should be needed, I'll follow your
> suggestion.

The dispute is that he apparently only looked at my RFC but didn't ask
me or check himself for newer code, which there was.

Regards,
Andreas

-- 
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Ivo Totev
HRB 36809 (AG Nürnberg)

Re: [PATCH v2 5/6] auxdisplay: add support for Titanmec TM1628 7 segment display controller

[Heiner Kallweit]

On 22.02.2022 13:16, Andreas Färber wrote:
> On 22.02.22 10:44, Heiner Kallweit wrote:
>> On 22.02.2022 09:19, Geert Uytterhoeven wrote:
>>> Hi Heiner,
>>>
>>> On Mon, Feb 21, 2022 at 9:26 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
>>>> This patch adds support for the Titanmec TM1628 7 segment display
>>>> controller. It's based on previous RFC work from Andreas Färber.
>>>> The RFC version placed the driver in the LED subsystem, but this was
>>>> NAK'ed by the LED maintainer. Therefore I moved the driver to
>>>> /drivers/auxdisplay what seems most reasonable to me.
>>>>
>>>> Further changes to the RFC version:
>>>> - Driver can be built also w/o LED class support, for displays that
>>>>   don't have any symbols to be exposed as LED's.
>>>> - Simplified the code and rewrote a lot of it.
>>>> - Driver is now kind of a MVP, but functionality should be sufficient
>>>>   for most use cases.
>>>> - Use the existing 7 segment support in uapi/linux/map_to_7segment.h
>>>>   as suggested by Geert Uytterhoeven.
>>>>
>>>> Note: There's a number of chips from other manufacturers that are
>>>>       almost identical, e.g. FD628, SM1628. Only difference I saw so
>>>>       far is that they partially support other display modes.
>>>>       TM1628: 6x12, 7x11
>>>>       SM1628C: 4x13, 5x12, 6x11, 7x10
>>>>       For typical displays on devices using these chips this
>>>>       difference shouldn't matter.
>>>>
>>>> Successfully tested on a TX3 Mini TV box that has an SM1628C and a
>>>> display with 4 digits and 7 symbols.
>>>>
>>>> Tested-by: Christian Hewitt <christianshewitt@gmail.com>
>>>> Signed-off-by: Andreas Färber <afaerber@suse.de>
>>>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>>>
>>> Thanks for your patch!
>>>
>>>> --- /dev/null
>>>> +++ b/drivers/auxdisplay/tm1628.c
>>>
>>>> +static int tm1628_show_text(struct tm1628 *s)
>>>> +{
>>>> +       static SEG7_CONVERSION_MAP(map_seg7, MAP_ASCII7SEG_ALPHANUM);
>>>
>>> This mapping can not be overridden by the user.  Is there any
>>> specific reason you didn't make the mapping configurable from sysfs,
>>> cfr. map_seg7_{show,store}() in include/uapi/linux/map_to_7segment.h?
>>>
>>
>> The more features an initial driver version includes, the more discussion
>> topics pop up and make it less likely that we end up with at least something.
>> I think there's a reason why the driver was resting since the initial
>> attempt 2 yrs ago. Therefore I'd like to keep it as a MVP. 
>> If somebody should have the need for add-on features, then they can be
>> added later.
> 
> As I pointed out in your v1, I did implement all that already, as was
> requested by Geert on my RFC:
> 
> https://github.com/afaerber/linux/commit/bbecf951348c7de8ba922c6c002a09369b717d82
> 
I don't want to prove how many API's I master, but give users what they need.
And that's simply:
- control symbols from kernel or user space -> LED class sysfs attributes / triggers
- write text (mainly numbers) to display -> sysfs attribute
And this with a minimum of code to facilitate maintenance.
As confirmed by Christian the proposed version gives him what he needs.

If there should be actually a demand for features like dimming control, then it
can be added later (e.g. you could add it based on the code you wrote already).

> Regards,
> Andreas
> 
Heiner

Re: [PATCH v2 3/6] dt-bindings: auxdisplay: Add Titan Micro Electronics TM1628

[Rob Herring]

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On Mon, 21 Feb 2022 21:23:18 +0100, Heiner Kallweit wrote:
> Add a YAML schema binding for TM1628 auxdisplay
> (7/11-segment LED) controller.
> 
> This patch is partially based on previous RFC work from
> Andreas Färber <afaerber@suse.de>.
> 
> Signed-off-by: Andreas Färber <afaerber@suse.de>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
> v2:
> - (re-)add Andreas' SoB
> - fix YAML errors reported by Rob
> ---
>  .../bindings/auxdisplay/titanmec,tm1628.yaml  | 88 +++++++++++++++++++
>  1 file changed, 88 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/auxdisplay/titanmec,tm1628.yaml
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/auxdisplay/titanmec,tm1628.example.dt.yaml: led-controller@0: 'spi-3-wire', 'spi-lsb-first', 'spi-max-frequency' do not match any of the regexes: '^.*@[1-7],([1-9]|1[0-6])$', 'pinctrl-[0-9]+'
	From schema: /builds/robherring/linux-dt-review/Documentation/devicetree/bindings/auxdisplay/titanmec,tm1628.yaml

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/patch/1595730

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit.