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Subject[PATCH v2] backlight: otm3225a: add support for ORISE OTM3225A LCD SoC
Date
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 <fb@ltec.ch>

Changes in v2:
- use descriptive names for registers instead of hard coding them
- remove unnecessary registers in initialization sequence
- make use of resource-managed functions like devm_kzalloc()
instead of kzalloc() which simplifies and shortens the code
- replace mdelay() by msleep()
- use module_spi_init() since we do not do anything special
in init/exit
- use dev_name() instead of hard coding driver name multiple times
- use static storage class for structure otm3225a_ops
- sort include files alphabetically
- use standardized licensing header
- modify Makefile respecting alphabetical sort order
---
drivers/video/backlight/Kconfig | 7 ++
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/otm3225a.c | 251 +++++++++++++++++++++++++++++++++++++
3 files changed, 259 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..2473377 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -12,6 +12,7 @@ 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
obj-$(CONFIG_LCD_S6E63M0) += s6e63m0.o
obj-$(CONFIG_LCD_TDO24M) += tdo24m.o
diff --git a/drivers/video/backlight/otm3225a.c b/drivers/video/backlight/otm3225a.c
new file mode 100644
index 0000000..cb1df6c
--- /dev/null
+++ b/drivers/video/backlight/otm3225a.c
@@ -0,0 +1,251 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Driver for ORISE Technology OTM3225A SOC for TFT LCD
+ * Copyright (C) 2017, EETS GmbH, Felix Brack <fb@ltec.ch>
+ *
+ * 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/delay.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/lcd.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+
+#define OTM3225A_INDEX_REG 0x70
+#define OTM3225A_DATA_REG 0x72
+
+/* instruncton register list */
+#define DRIVER_OUTPUT_CTRL_1 0x01
+#define DRIVER_WAVEFORM_CTRL 0x02
+#define ENTRY_MODE 0x03
+#define SCALING_CTRL 0x04
+#define DISPLAY_CTRL_1 0x07
+#define DISPLAY_CTRL_2 0x08
+#define DISPLAY_CTRL_3 0x09
+#define FRAME_CYCLE_CTRL 0x0A
+#define EXT_DISP_IFACE_CTRL_1 0x0C
+#define FRAME_MAKER_POS 0x0D
+#define EXT_DISP_IFACE_CTRL_2 0x0F
+#define POWER_CTRL_1 0x10
+#define POWER_CTRL_2 0x11
+#define POWER_CTRL_3 0x12
+#define POWER_CTRL_4 0x13
+#define GRAM_ADDR_HORIZ_SET 0x20
+#define GRAM_ADDR_VERT_SET 0x21
+#define GRAM_READ_WRITE 0x22
+#define POWER_CTRL_7 0x29
+#define FRAME_RATE_CTRL 0x2B
+#define GAMMA_CTRL_1 0x30
+#define GAMMA_CTRL_2 0x31
+#define GAMMA_CTRL_3 0x32
+#define GAMMA_CTRL_4 0x35
+#define GAMMA_CTRL_5 0x36
+#define GAMMA_CTRL_6 0x37
+#define GAMMA_CTRL_7 0x38
+#define GAMMA_CTRL_8 0x39
+#define GAMMA_CTRL_9 0x3C
+#define GAMMA_CTRL_10 0x3D
+#define WINDOW_HORIZ_RAM_START 0x50
+#define WINDOW_HORIZ_RAM_END 0x51
+#define WINDOW_VERT_RAM_START 0x52
+#define WINDOW_VERT_RAM_END 0x53
+#define DRIVER_OUTPUT_CTRL_2 0x60
+#define BASE_IMG_DISPLAY_CTRL 0x61
+#define VERT_SCROLL_CTRL 0x6A
+#define PD1_DISPLAY_POS 0x80
+#define PD1_RAM_START 0x81
+#define PD1_RAM_END 0x82
+#define PD2_DISPLAY_POS 0x83
+#define PD2_RAM_START 0x84
+#define PD2_RAM_END 0x85
+#define PANEL_IFACE_CTRL_1 0x90
+#define PANEL_IFACE_CTRL_2 0x92
+#define PANEL_IFACE_CTRL_4 0x95
+#define PANEL_IFACE_CTRL_5 0x97
+
+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[] = {
+ { DRIVER_OUTPUT_CTRL_1, 0x0000, 0 },
+ { DRIVER_WAVEFORM_CTRL, 0x0700, 0 },
+ { ENTRY_MODE, 0x50A0, 0 },
+ { SCALING_CTRL, 0x0000, 0 },
+ { DISPLAY_CTRL_2, 0x0606, 0 },
+ { DISPLAY_CTRL_3, 0x0000, 0 },
+ { FRAME_CYCLE_CTRL, 0x0000, 0 },
+ { EXT_DISP_IFACE_CTRL_1, 0x0000, 0 },
+ { FRAME_MAKER_POS, 0x0000, 0 },
+ { EXT_DISP_IFACE_CTRL_2, 0x0002, 0 },
+ { POWER_CTRL_2, 0x0007, 0 },
+ { POWER_CTRL_3, 0x0000, 0 },
+ { POWER_CTRL_4, 0x0000, 200 },
+ { DISPLAY_CTRL_1, 0x0101, 0 },
+ { POWER_CTRL_1, 0x12B0, 0 },
+ { POWER_CTRL_2, 0x0007, 0 },
+ { POWER_CTRL_3, 0x01BB, 50 },
+ { POWER_CTRL_4, 0x0013, 0 },
+ { POWER_CTRL_7, 0x0010, 50 },
+ { GAMMA_CTRL_1, 0x000A, 0 },
+ { GAMMA_CTRL_2, 0x1326, 0 },
+ { GAMMA_CTRL_3, 0x0A29, 0 },
+ { GAMMA_CTRL_4, 0x0A0A, 0 },
+ { GAMMA_CTRL_5, 0x1E03, 0 },
+ { GAMMA_CTRL_6, 0x031E, 0 },
+ { GAMMA_CTRL_7, 0x0706, 0 },
+ { GAMMA_CTRL_8, 0x0303, 0 },
+ { GAMMA_CTRL_9, 0x010E, 0 },
+ { GAMMA_CTRL_10, 0x040E, 0 },
+ { WINDOW_HORIZ_RAM_START, 0x0000, 0 },
+ { WINDOW_HORIZ_RAM_END, 0x00EF, 0 },
+ { WINDOW_VERT_RAM_START, 0x0000, 0 },
+ { WINDOW_VERT_RAM_END, 0x013F, 0 },
+ { DRIVER_OUTPUT_CTRL_2, 0x2700, 0 },
+ { BASE_IMG_DISPLAY_CTRL, 0x0001, 0 },
+ { VERT_SCROLL_CTRL, 0x0000, 0 },
+ { PD1_DISPLAY_POS, 0x0000, 0 },
+ { PD1_RAM_START, 0x0000, 0 },
+ { PD1_RAM_END, 0x0000, 0 },
+ { PD2_DISPLAY_POS, 0x0000, 0 },
+ { PD2_RAM_START, 0x0000, 0 },
+ { PD2_RAM_END, 0x0000, 0 },
+ { PANEL_IFACE_CTRL_1, 0x0010, 0 },
+ { PANEL_IFACE_CTRL_2, 0x0000, 0 },
+ { PANEL_IFACE_CTRL_4, 0x0210, 0 },
+ { PANEL_IFACE_CTRL_5, 0x0000, 0 },
+ { DISPLAY_CTRL_1, 0x0133, 0 },
+};
+
+static struct otm3225a_spi_instruction display_enable_rgb_interface[] = {
+ { ENTRY_MODE, 0x1080, 0 },
+ { GRAM_ADDR_HORIZ_SET, 0x0000, 0 },
+ { GRAM_ADDR_VERT_SET, 0x0000, 0 },
+ { EXT_DISP_IFACE_CTRL_1, 0x0111, 500 },
+};
+
+static struct otm3225a_spi_instruction display_off[] = {
+ { DISPLAY_CTRL_1, 0x0131, 100 },
+ { DISPLAY_CTRL_1, 0x0130, 100 },
+ { DISPLAY_CTRL_1, 0x0100, 0 },
+ { POWER_CTRL_1, 0x0280, 0 },
+ { POWER_CTRL_3, 0x018B, 0 },
+};
+
+static struct otm3225a_spi_instruction display_on[] = {
+ { POWER_CTRL_1, 0x1280, 0 },
+ { DISPLAY_CTRL_1, 0x0101, 100 },
+ { DISPLAY_CTRL_1, 0x0121, 0 },
+ { DISPLAY_CTRL_1, 0x0123, 100 },
+ { DISPLAY_CTRL_1, 0x0133, 10 },
+};
+
+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 */
+ msleep(instruction->delay);
+ 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;
+}
+
+static 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;
+ struct device *dev = &spi->dev;
+
+ dd = devm_kzalloc(dev, sizeof(struct otm3225a_data), GFP_KERNEL);
+ if (dd == NULL)
+ return -ENOMEM;
+
+ ld = devm_lcd_device_register(dev, dev_name(dev), dev, dd,
+ &otm3225a_ops);
+ if (IS_ERR(ld))
+ return PTR_ERR(ld);
+
+ dd->spi = spi;
+ dd->ld = ld;
+ dev_set_drvdata(dev, dd);
+
+ dev_info(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));
+ return 0;
+}
+
+static struct spi_driver otm3225a_driver = {
+ .driver = {
+ .name = "otm3225a",
+ .owner = THIS_MODULE,
+ },
+ .probe = otm3225a_probe,
+};
+
+module_spi_driver(otm3225a_driver);
+
+MODULE_AUTHOR("Felix Brack <fb@ltec.ch>");
+MODULE_DESCRIPTION("OTM3225A TFT LCD driver");
+MODULE_VERSION("1.0.0");
+MODULE_LICENSE("GPL v2");
--
2.7.4
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