On Wednesday, December 20, 2017 12:58 PM, Felix Brack wrote:

quoted

This patch adds a LCD driver supporting the OTM3225A LCD SoC
from ORISE Technology. This device can drive TFT LC panels having a
resolution of 240x320 pixels. After initializing the OTM3225A using
it's SPI interface it switches to use 16-bib RGB as external
display interface.

Signed-off-by: Felix Brack <redacted>
---
 drivers/video/backlight/Kconfig    |   7 ++
 drivers/video/backlight/Makefile   |   1 +
 drivers/video/backlight/otm3225a.c | 210
+++++++++++++++++++++++++++++++++++++
 3 files changed, 218 insertions(+)
 create mode 100644 drivers/video/backlight/otm3225a.c

diff --git a/drivers/video/backlight/Kconfig

b/drivers/video/backlight/Kconfig
index 4e1d2ad..06e187b 100644

--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig

@@ -150,6 +150,13 @@ config LCD_HX8357
 	  If you have a HX-8357 LCD panel, say Y to enable its LCD control
 	  driver.

+  config LCD_OTM3225A
+  	tristate "ORISE Technology OTM3225A support"
+  	depends on SPI
+  	help
+  	  If you have a panel based on the OTM3225A controller
+  	  chip then say y to include a driver for it.
+
 endif # LCD_CLASS_DEVICE

 #

diff --git a/drivers/video/backlight/Makefile

b/drivers/video/backlight/Makefile
index 8905129..b177b91 100644

--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile

@@ -17,6 +17,7 @@ obj-$(CONFIG_LCD_S6E63M0)		+= s6e63m0.o
 obj-$(CONFIG_LCD_TDO24M)		+= tdo24m.o
 obj-$(CONFIG_LCD_TOSA)			+= tosa_lcd.o
 obj-$(CONFIG_LCD_VGG2432A4)		+= vgg2432a4.o
+obj-$(CONFIG_LCD_OTM3225A)		+= otm3225a.o

All entries of Kconfig was alphasorted 4 years ago for reducing
patch collisions. So please add it in alphabetical order as below.

@@ -13,6 +13,7 @@ obj-$(CONFIG_LCD_LD9040)              += ld9040.o
 obj-$(CONFIG_LCD_LMS283GF05)           += lms283gf05.o
 obj-$(CONFIG_LCD_LMS501KF03)           += lms501kf03.o
 obj-$(CONFIG_LCD_LTV350QV)             += ltv350qv.o
+obj-$(CONFIG_LCD_OTM3225A)             += otm3225a.o
 obj-$(CONFIG_LCD_PLATFORM)             += platform_lcd.o

quoted

 obj-$(CONFIG_BACKLIGHT_88PM860X)	+= 88pm860x_bl.o
 obj-$(CONFIG_BACKLIGHT_AAT2870)		+= aat2870_bl.o

diff --git a/drivers/video/backlight/otm3225a.c

b/drivers/video/backlight/otm3225a.c
new file mode 100644
index 0000000..0de75f8

--- /dev/null
+++ b/drivers/video/backlight/otm3225a.c

@@ -0,0 +1,210 @@
+/*
+ * Driver for ORISE Technology OTM3225A SOC for TFT LCD
+ *
+ * Copyright (C) 2014-2017, EETS GmbH, Felix Brack <fb@ltec.ch>

Please change the year of copyright as below.

+ * Copyright (C) 2017, EETS GmbH, Felix Brack [off-list ref]

quoted

+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * This driver implements a lcd device for the ORISE OTM3225A display
+ * controller. The control interface to the display is SPI and the
display's
+ * memory is updated over the 16-bit RGB interface.
+ * The main source of information for writing this driver was provided by
the
+ * OTM3225A datasheet from ORISE Technology. Some information arise from
the
+ * ILI9328 datasheet from ILITEK as well as from the datasheets and
sample code
+ * provided by Crystalfontz America Inc. who sells the CFAF240320A-032T,
a 3.2"
+ * TFT LC display using the OTM3225A controller.
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/lcd.h>
+#include <linux/spi/spi.h>

So please add these headers in alphabetical order
for readability.

quoted

+
+#define OTM3225A_INDEX_REG	0x70
+#define OTM3225A_DATA_REG	0x72
+
+struct otm3225a_data {
+	struct spi_device *spi;
+	struct lcd_device *ld;
+	int power;
+};
+
+struct otm3225a_spi_instruction {
+	unsigned char reg;	/* register to write */
+	unsigned short value;	/* data to write to 'reg' */
+	unsigned short delay;	/* delay in ms after write */
+};
+
+static struct otm3225a_spi_instruction display_init[] = {
+	{ 0x01, 0x0000, 0 }, { 0x02, 0x0700, 0 }, { 0x03, 0x50A0, 0 },
+	{ 0x04, 0x0000, 0 }, { 0x08, 0x0606, 0 }, { 0x09, 0x0000, 0 },
+	{ 0x0A, 0x0000, 0 }, { 0x0C, 0x0000, 0 }, { 0x0D, 0x0000, 0 },
+	{ 0x0F, 0x0002, 0 }, { 0x11, 0x0007, 0 }, { 0x12, 0x0000, 0 },
+	{ 0x13, 0x0000, 200 }, { 0x07, 0x0101, 0 }, { 0x10, 0x12B0, 0 },
+	{ 0x11, 0x0007, 0 }, { 0x12, 0x01BB, 50 }, { 0xB1, 0x0000, 0 },
+	{ 0xB3, 0x0000, 0 }, { 0xB5, 0x0000, 0 }, { 0xBE, 0x0000, 0 },
+	{ 0x13, 0x0013, 0 }, { 0x29, 0x0010, 50 }, { 0x30, 0x000A, 0 },
+	{ 0x31, 0x1326, 0 }, { 0x32, 0x0A29, 0 }, { 0x35, 0x0A0A, 0 },
+	{ 0x36, 0x1E03, 0 }, { 0x37, 0x031E, 0 }, { 0x38, 0x0706, 0 },
+	{ 0x39, 0x0303, 0 }, { 0x3C, 0x010E, 0 }, { 0x3D, 0x040E, 0 },
+	{ 0x50, 0x0000, 0 }, { 0x51, 0x00EF, 0 }, { 0x52, 0x0000, 0 },
+	{ 0x53, 0x013F, 0 }, { 0x60, 0x2700, 0 }, { 0x61, 0x0001, 0 },
+	{ 0x6A, 0x0000, 0 }, { 0x80, 0x0000, 0 }, { 0x81, 0x0000, 0 },
+	{ 0x82, 0x0000, 0 }, { 0x83, 0x0000, 0 }, { 0x84, 0x0000, 0 },
+	{ 0x85, 0x0000, 0 }, { 0x90, 0x0010, 0 }, { 0x92, 0x0000, 0 },
+	{ 0x93, 0x0103, 0 }, { 0x95, 0x0210, 0 }, { 0x97, 0x0000, 0 },
+	{ 0x98, 0x0000, 0 }, { 0x07, 0x0133, 0 },
+};
+
+static struct otm3225a_spi_instruction display_enable_rgb_interface[] = {
+	{ 0x03, 0x1080, 0 },
+	{ 0x20, 0x0000, 0 },
+	{ 0x21, 0x0000, 0 },
+	{ 0x0C, 0x0111, 500 },
+};
+
+static struct otm3225a_spi_instruction display_off[] = {
+	{ 0x07, 0x0131, 100 },
+	{ 0x07, 0x0130, 100 },
+	{ 0x07, 0x0100, 0 },
+	{ 0x10, 0x0280, 0 },
+	{ 0x12, 0x018B, 0 },
+};
+
+static struct otm3225a_spi_instruction display_on[] = {
+	{ 0x10, 0x1280, 0 },
+	{ 0x07, 0x0101, 100 },
+	{ 0x07, 0x0121, 0 },
+	{ 0x07, 0x0123, 100 },
+	{ 0x07, 0x0133, 10 },
+};

Please change these hardcoded values into register define.
I found the datasheet of OTM3225A. I think you can change
the hardcoding for readability.
(https://www.crystalfontz.com/controllers/OriseTech/OTM3225A/196/)

For example, you can add register define and change display_on[]
as below.

#define DISPLAY_CONTROL_1		0x07
#define POWER_CONTROL_1			0x10

+static struct otm3225a_spi_instruction display_on[] = {
+	{ POWER_CONTROL_1, 0x1280, 0 },
+	{ DISPLAY_CONTROL_1, 0x0101, 100 },
+	{ DISPLAY_CONTROL_1, 0x0121, 0 },
+	{ DISPLAY_CONTROL_1, 0x0123, 100 },
+	{ DISPLAY_CONTROL_1, 0x0133, 10 },
+};

quoted

+
+static void otm3225a_write(struct spi_device *spi,
+			   struct otm3225a_spi_instruction *instruction,
+			   unsigned int count)
+{
+	unsigned char buf[3];
+
+	while (count--) {
+		/* address register using index register */
+		buf[0] = OTM3225A_INDEX_REG;
+		buf[1] = 0x00;
+		buf[2] = instruction->reg;
+		spi_write(spi, buf, 3);
+
+		/* write data to addressed register */
+		buf[0] = OTM3225A_DATA_REG;
+		buf[1] = (instruction->value >> 8) & 0xff;
+		buf[2] = instruction->value & 0xff;
+		spi_write(spi, buf, 3);
+
+		/* execute delay if any */
+		mdelay(instruction->delay);

Please use msleep instead of mdelay.

quoted

+		instruction++;
+	}
+}
+
+static int otm3225a_set_power(struct lcd_device *ld, int power)
+{
+	struct otm3225a_data *dd = lcd_get_data(ld);
+
+	if (power = dd->power)
+		return 0;
+
+	if (power > FB_BLANK_UNBLANK)
+		otm3225a_write(dd->spi, display_off,
ARRAY_SIZE(display_off));
+	else
+		otm3225a_write(dd->spi, display_on, ARRAY_SIZE(display_on));
+	dd->power = power;
+
+	return 0;
+}
+
+static int otm3225a_get_power(struct lcd_device *ld)
+{
+	struct otm3225a_data *dd = lcd_get_data(ld);
+
+	return dd->power;
+}
+
+struct lcd_ops otm3225a_ops = {
+	.set_power = otm3225a_set_power,
+	.get_power = otm3225a_get_power,
+};
+
+static int otm3225a_probe(struct spi_device *spi)
+{
+	struct otm3225a_data *dd;
+	struct lcd_device *ld;
+	int ret = 0;
+
+	dd = kzalloc(sizeof(struct otm3225a_data), GFP_KERNEL);

Please use devm_kzalloc(), then you don't need to use kfree(dd)
in otm3225a_remove().

quoted

+	if (dd = NULL) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ld = lcd_device_register("otm3225a", &spi->dev, dd, &otm3225a_ops);

Please use devm_lcd_device_register(), then you don't need
to use lcd_device_unregister() in otm3225a_remove().

quoted

+	if (IS_ERR(ld)) {
+		ret = PTR_ERR(ld);
+		goto err;
+	}
+	dd->spi = spi;
+	dd->ld = ld;
+	dev_set_drvdata(&spi->dev, dd);
+
+	dev_info(&spi->dev, "Initializing and switching to RGB interface");
+	otm3225a_write(spi, display_init, ARRAY_SIZE(display_init));
+	otm3225a_write(spi, display_enable_rgb_interface,
+		       ARRAY_SIZE(display_enable_rgb_interface));
+
+err:
+	return ret;
+}
+
+static int otm3225a_remove(struct spi_device *spi)
+{
+	struct otm3225a_data *dd;
+
+	dd = dev_get_drvdata(&spi->dev);
+	lcd_device_unregister(dd->ld);
+	kfree(dd);

If you use devm_kzalloc() and devm_lcd_device_register()
in otm3225a_probe as I mentioned above, you can remove
lcd_device_unregister() and kfree() here.

If so, you don't need otm3225a_remove().
What I want to say is that you can add only probe() function
when you use devm_* functions in your otm3225a driver code.

quoted

+	return 0;
+}
+
+static struct spi_driver otm3225a_driver = {
+	.driver = {
+		.name = "otm3225a",
+		.owner = THIS_MODULE,
+	},
+	.probe = otm3225a_probe,
+	.remove = otm3225a_remove,

If you use devm_kzalloc() and devm_lcd_device_register(),
you can remove otm3225a_remove() as below.

+static struct spi_driver otm3225a_driver = {
+	.driver = {
+		.name = "otm3225a",
+		.owner = THIS_MODULE,
+	},
+	.probe = otm3225a_probe,
+};

Please refer to the following driver.
./drivers/video/backlight/tps65217_bl.c

quoted

+};
+
+static __init int otm3225a_init(void)
+{
+	return (&otm3225a_driver);
+}
+
+static __exit void otm3225a_exit(void)
+{
+	spi_unregister_driver(&otm3225a_driver);
+}
+
+module_init(otm3225a_init);
+module_exit(otm3225a_exit);

Instead of adding otm3225a_init(), otm3225a_exit(), 
please use module_spi_driver macro as below.
This macro can reduce source code lines.

module_spi_driver(otm3225a_driver);

Best regards,
Jingoo Han

quoted

+
+MODULE_AUTHOR("Felix Brack [off-list ref]");
+MODULE_DESCRIPTION("OTM3225A TFT LCD driver");
+MODULE_VERSION("1.0.0");
+MODULE_LICENSE("GPL v2");
--
2.7.4