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SubjectRe: [PATCH] backlight: otm3225a: add support for ORISE OTM3225A LCD SoC
Date
On Wednesday, December 20, 2017 12:58 PM, Felix Brack wrote:
>
> 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>
> ---
> 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


>
> 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 <fb@ltec.ch>

> + *
> + * 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.

> +
> +#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 },
+};

> +
> +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.

> + 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().

> + 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().

> + 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.

> + 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

> +};
> +
> +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

> +
> +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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