Re: [PATCH v4 32/32] auxdisplay: add a driver for lcd2s character display

[Miguel Ojeda]

On Mon, Oct 5, 2020 at 3:01 PM  wrote:
>
> +   while (*esc && i < LCD2S_CHARACTER_SIZE + 2) {
> +   shift ^= 4;
> +   if (*esc >= '0' && *esc <= '9') {
> +   value |= (*esc - '0') << shift;
> +   } else if (*esc >= 'A' && *esc <= 'Z') {
> +   value |= (*esc - 'A' + 10) << shift;
> +   } else if (*esc >= 'a' && *esc <= 'z') {
> +   value |= (*esc - 'a' + 10) << shift;

This should also probably use hex_to_bin() or similar (see my other
comment on patch 24) and/or share the implementation as much as
possible.

Cheers,
Miguel

[PATCH v4 32/32] auxdisplay: add a driver for lcd2s character display

[poeschel]

From: Lars Poeschel 

This driver allows to use a lcd2s 20x4 character display from Modtronix
engineering as an auxdisplay charlcd device.

Signed-off-by: Lars Poeschel 
---
Changes in v4:
- modtronix -> Modtronix
- Kconfig: remove "default n"

---
 drivers/auxdisplay/Kconfig  |  10 +
 drivers/auxdisplay/Makefile |   1 +
 drivers/auxdisplay/lcd2s.c  | 409 
 3 files changed, 420 insertions(+)
 create mode 100644 drivers/auxdisplay/lcd2s.c

diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig
index a56171d1a1ba..96c8cdfce48d 100644
--- a/drivers/auxdisplay/Kconfig
+++ b/drivers/auxdisplay/Kconfig
@@ -173,6 +173,16 @@ config HT16K33
  Say yes here to add support for Holtek HT16K33, RAM mapping 16*8
  LED controller driver with keyscan.
 
+config LCD2S
+   tristate "lcd2s 20x4 character display over I2C console"
+   depends on I2C
+   select CHARLCD
+   help
+ This is a driver that lets you use the lcd2s 20x4 character display
+ from Modtronix engineering as a console output device. The display
+ is a simple single color character display. You have to connect it
+ to an I2C bus.
+
 config ARM_CHARLCD
bool "ARM Ltd. Character LCD Driver"
depends on PLAT_VERSATILE
diff --git a/drivers/auxdisplay/Makefile b/drivers/auxdisplay/Makefile
index 7e8a8c3eb3c3..307771027c89 100644
--- a/drivers/auxdisplay/Makefile
+++ b/drivers/auxdisplay/Makefile
@@ -12,3 +12,4 @@ obj-$(CONFIG_IMG_ASCII_LCD)   += img-ascii-lcd.o
 obj-$(CONFIG_HD44780)  += hd44780.o
 obj-$(CONFIG_HT16K33)  += ht16k33.o
 obj-$(CONFIG_PARPORT_PANEL)+= panel.o
+obj-$(CONFIG_LCD2S)+= lcd2s.o
diff --git a/drivers/auxdisplay/lcd2s.c b/drivers/auxdisplay/lcd2s.c
new file mode 100644
index ..4b8c597a26fa
--- /dev/null
+++ b/drivers/auxdisplay/lcd2s.c
@@ -0,0 +1,409 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  console driver for LCD2S 4x20 character displays connected through i2c.
+ *  The display also has a spi interface, but the driver does not support
+ *  this yet.
+ *
+ *  This is a driver allowing you to use a LCD2S 4x20 from modtronix
+ *  engineering as auxdisplay character device.
+ *
+ *  (C) 2019 by Lemonage Software GmbH
+ *  Author: Lars Pöschel 
+ *  All rights reserved.
+ */
+#include 
+#include 
+#include 
+#include 
+#include 
+
+#include "charlcd.h"
+
+#define LCD2S_CMD_CUR_MOVES_FWD0x09
+#define LCD2S_CMD_CUR_BLINK_OFF0x10
+#define LCD2S_CMD_CUR_UL_OFF   0x11
+#define LCD2S_CMD_DISPLAY_OFF  0x12
+#define LCD2S_CMD_CUR_BLINK_ON 0x18
+#define LCD2S_CMD_CUR_UL_ON0x19
+#define LCD2S_CMD_DISPLAY_ON   0x1a
+#define LCD2S_CMD_BACKLIGHT_OFF0x20
+#define LCD2S_CMD_BACKLIGHT_ON 0x28
+#define LCD2S_CMD_WRITE0x80
+#define LCD2S_CMD_MOV_CUR_RIGHT0x83
+#define LCD2S_CMD_MOV_CUR_LEFT 0x84
+#define LCD2S_CMD_SHIFT_RIGHT  0x85
+#define LCD2S_CMD_SHIFT_LEFT   0x86
+#define LCD2S_CMD_SHIFT_UP 0x87
+#define LCD2S_CMD_SHIFT_DOWN   0x88
+#define LCD2S_CMD_CUR_ADDR 0x89
+#define LCD2S_CMD_CUR_POS  0x8a
+#define LCD2S_CMD_CUR_RESET0x8b
+#define LCD2S_CMD_CLEAR0x8c
+#define LCD2S_CMD_DEF_CUSTOM_CHAR  0x92
+#define LCD2S_CMD_READ_STATUS  0xd0
+
+#define LCD2S_CHARACTER_SIZE   8
+
+#define LCD2S_STATUS_BUF_MASK  0x7f
+
+struct lcd2s_data {
+   struct i2c_client *i2c;
+   struct charlcd *charlcd;
+};
+
+static s32 lcd2s_wait_buf_free(const struct i2c_client *client, int count)
+{
+   s32 status;
+
+   status = i2c_smbus_read_byte_data(client, LCD2S_CMD_READ_STATUS);
+   if (status < 0)
+   return status;
+
+   while ((status & LCD2S_STATUS_BUF_MASK) < count) {
+   mdelay(1);
+   status = i2c_smbus_read_byte_data(client,
+ LCD2S_CMD_READ_STATUS);
+   if (status < 0)
+   return status;
+   }
+   return 0;
+}
+
+static int lcd2s_i2c_master_send(const struct i2c_client *client,
+const char *buf, int count)
+{
+   s32 status;
+
+   status = lcd2s_wait_buf_free(client, count);
+   if (status < 0)
+   return status;
+
+   return i2c_master_send(client, buf, count);
+}
+
+static int lcd2s_i2c_smbus_write_byte(const struct i2c_client *client, u8 
value)
+{
+   s32 status;
+
+   status = lcd2s_wait_buf_free(client, 1);
+   if (status < 0)
+   return status;
+
+   return i2c_smbus_write_byte(client, value);
+}
+
+static int lcd2s_print(struct charlcd *lcd, int c)
+{
+   struct lcd2s_data *lcd2s = lcd->drvdata;
+   u8 buf[2] = { LCD2S_CMD_WRITE, c };
+
+   lcd2s_i2c_master_send(lcd2s->i2c, buf, s