Re: [PATCH 1/1] OMAP: DSS2: Add TI Boxer display panel driver

[Archit Taneja <archit@ti.com>]

Hi,

Some comments.

On Saturday 15 October 2011 08:15 PM, Javier Martinez Canillas wrote:
> Add panel driver for TI Boxer LCD.
>
> This panel is used on many embedded devices such as
> Barnes&  Nobles's Nook Color e-reader.
>
> Signed-off-by: Javier Martinez Canillas<martinez.javier@gmail.com>
> ---
>   drivers/video/omap2/displays/Kconfig       |    6 +
>   drivers/video/omap2/displays/Makefile      |    1 +
>   drivers/video/omap2/displays/panel-boxer.c |  333 ++++++++++++++++++++++++++++
>   3 files changed, 340 insertions(+), 0 deletions(-)
>   create mode 100644 drivers/video/omap2/displays/panel-boxer.c
>
> diff --git a/drivers/video/omap2/displays/Kconfig b/drivers/video/omap2/displays/Kconfig
> index 609a280..6c9fe26 100644
> --- a/drivers/video/omap2/displays/Kconfig
> +++ b/drivers/video/omap2/displays/Kconfig
> @@ -48,4 +48,10 @@ config PANEL_ACX565AKM
>   	select BACKLIGHT_CLASS_DEVICE
>   	help
>   	  This is the LCD panel used on Nokia N900
> +
> +config PANEL_BOXER
> +        tristate "TI Boxer Panel"
> +        help
> +          LCD Panel used in the TI Boxer
> +
>   endmenu
> diff --git a/drivers/video/omap2/displays/Makefile b/drivers/video/omap2/displays/Makefile
> index 0f601ab3a..26c662e 100644
> --- a/drivers/video/omap2/displays/Makefile
> +++ b/drivers/video/omap2/displays/Makefile
> @@ -6,3 +6,4 @@ obj-$(CONFIG_PANEL_NEC_NL8048HL11_01B) += panel-nec-nl8048hl11-01b.o
>   obj-$(CONFIG_PANEL_TAAL) += panel-taal.o
>   obj-$(CONFIG_PANEL_TPO_TD043MTEA1) += panel-tpo-td043mtea1.o
>   obj-$(CONFIG_PANEL_ACX565AKM) += panel-acx565akm.o
> +obj-$(CONFIG_PANEL_BOXER) += panel-boxer.o
> diff --git a/drivers/video/omap2/displays/panel-boxer.c b/drivers/video/omap2/displays/panel-boxer.c
> new file mode 100644
> index 0000000..6429960
> --- /dev/null
> +++ b/drivers/video/omap2/displays/panel-boxer.c
> @@ -0,0 +1,333 @@
> +/*
> + * Boxer panel support
> + *
> + * Copyright (C) 2008 Nokia Corporation
> + * Author: Tomi Valkeinen<tomi.valkeinen@nokia.com>
> + *
> + * Copyright (c) 2010 Barnes&  Noble
> + * David Bolcsfoldi<dbolcsfoldi@intrinsyc.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see<http://www.gnu.org/licenses/>.
> + */
> +
> +#include<linux/module.h>
> +#include<linux/kernel.h>
> +#include<linux/delay.h>
> +#include<linux/platform_device.h>
> +#include<linux/spi/spi.h>
> +#include<linux/regulator/consumer.h>
> +#include<linux/err.h>
> +#include<linux/workqueue.h>
> +
> +#include<plat/mcspi.h>
> +#include<mach/gpio.h>
> +#include<mach/gpio.h>
> +#include<plat/mux.h>
> +#include<asm/mach-types.h>
> +
> +#include<video/omapdss.h>
> +
> +/* Delay between Panel configuration and Panel enabling */
> +#define LCD_RST_DELAY		100
> +#define LCD_INIT_DELAY		200
> +
> +#define LCD_XRES		1024
> +#define LCD_YRES		600
> +
> +#define LCD_PIXCLOCK_MIN	39000 /* CPT MIN PIX Clock is 39MHz */
> +#define Lcd_Pixclock_Typ	45000 /* Typical PIX clock is 45MHz */
> +#define LCD_PIXCLOCK_MAX	52000 /* Maximum is 52MHz */

These don't seem to be used. We should remove these.

> +
> +/* Current Pixel clock */
> +#define LCD_PIXEL_CLOCK		68000
> +
> +static struct workqueue_struct *boxer_panel_wq;
> +static struct omap_dss_device *boxer_panel_dssdev;
> +static struct regulator *boxer_panel_regulator;
> +static struct spi_device *boxer_spi_device;
> +static atomic_t boxer_panel_is_enabled = ATOMIC_INIT(0);

It would be cleaner to group these together as one driver data struct. 
This struct can then be kzalloc'd at probe, and be linked to the dssdev 
struct through 'dev_set_drvdata', this will help the driver support more 
than one instances of boxer panel devices running in parallel. You could 
see panel-generic-dpi.c for reference.

> +
> +/*NEC NL8048HL11-01B  Manual
> + * defines HFB, HSW, HBP, VFP, VSW, VBP as shown below
> + */

Its not clear what the comment above is trying to say. Is panel boxer 
"NEC NL8048HL11-01B"?

> +
> +static struct omap_video_timings boxer_panel_timings = {
> +	/* 1024 x 600 @ 60 Hz  Reduced blanking VESA CVT 0.31M3-R */
> +	.x_res          = LCD_XRES,
> +	.y_res          = LCD_YRES,
> +	.pixel_clock    = LCD_PIXEL_CLOCK,
> +	.hfp            = 48,
> +	.hsw            = 40,
> +	.hbp            = 65,
> +	.vfp            = 3,
> +	.vsw            = 10,
> +	.vbp            = 25,
> +};
> +
> +static void boxer_get_resolution(struct omap_dss_device *dssdev,
> +				 u16 *xres, u16 *yres)
> +{
> +
> +	*xres = dssdev->panel.timings.x_res;
> +	*yres = dssdev->panel.timings.y_res;
> +}
> +
> +int boxer_get_recommended_bpp(struct omap_dss_device *dssdev)
> +{
> +	return 24;
> +}
> +
> +
> +static int boxer_panel_probe(struct omap_dss_device *dssdev)
> +{
> +	dssdev->panel.config = OMAP_DSS_LCD_TFT | OMAP_DSS_LCD_IVS |
> +		OMAP_DSS_LCD_IHS | OMAP_DSS_LCD_IPC;
> +	dssdev->panel.timings = boxer_panel_timings;
> +	return 0;
> +}
> +
> +static void boxer_panel_remove(struct omap_dss_device *dssdev)
> +{
> +}
> +
> +static int spi_send(struct spi_device *spi, unsigned char reg_addr,
> +		    unsigned char reg_data)
> +{
> +	int ret = 0;
> +	uint16_t msg;
> +	msg = (reg_addr<<  10) | reg_data;
> +
> +	if (spi_write(spi, (unsigned char *)&msg, 2))
> +		printk(KERN_ERR "error in spi_write %x\n", msg);
> +
> +	udelay(10);
> +
> +	return ret;
> +}
> +
> +static void boxer_init_panel(void)
> +{
> +	spi_send(boxer_spi_device, 0, 0x00);
> +
> +	spi_send(boxer_spi_device,   0, 0xad);
> +	spi_send(boxer_spi_device,   1, 0x30);
> +	spi_send(boxer_spi_device,   2, 0x40);

You might want to use hex representations above for consistency.

> +	spi_send(boxer_spi_device, 0xe, 0x5f);
> +	spi_send(boxer_spi_device, 0xf, 0xa4);
> +	spi_send(boxer_spi_device, 0xd, 0x00);
> +	spi_send(boxer_spi_device, 0x2, 0x43);
> +	spi_send(boxer_spi_device, 0xa, 0x28);
> +	spi_send(boxer_spi_device, 0x10, 0x41);
> +}
> +
> +static void boxer_panel_work_func(struct work_struct *work)
> +{
> +	if (!regulator_is_enabled(boxer_panel_regulator))
> +		regulator_enable(boxer_panel_regulator);
> +
> +	msleep(LCD_RST_DELAY);
> +
> +	boxer_spi_device->mode = SPI_MODE_0;
> +	boxer_spi_device->bits_per_word = 16;
> +	spi_setup(boxer_spi_device);
> +
> +	boxer_init_panel();
> +
> +	msleep(LCD_INIT_DELAY);
> +
> +	if (boxer_panel_dssdev->platform_enable)
> +		boxer_panel_dssdev->platform_enable(boxer_panel_dssdev);
> +}
> +
> +static DECLARE_WORK(boxer_panel_work, boxer_panel_work_func);
> +
> +static int boxer_panel_enable(struct omap_dss_device *dssdev)
> +{
> +	if (atomic_add_unless(&boxer_panel_is_enabled, 1, 1)) {
> +		boxer_panel_dssdev = dssdev;
> +		queue_work(boxer_panel_wq,&boxer_panel_work);
> +	}
> +

You need to set the dssdev->state values correctly in the 
enable/disable/suspend/resume functions, otherwise DSS2 won't have the 
correct knowledge of the panel state.

> +	return 0;
> +}
> +
> +static void boxer_panel_disable(struct omap_dss_device *dssdev)
> +{
> +	if (atomic_dec_and_test(&boxer_panel_is_enabled)) {
> +		cancel_work_sync(&boxer_panel_work);
> +
> +		if (dssdev->platform_disable)
> +			dssdev->platform_disable(dssdev);
> +
> +		if (regulator_is_enabled(boxer_panel_regulator))
> +			regulator_disable(boxer_panel_regulator);
> +	} else {
> +		printk(KERN_WARNING "%s: attempting to disable panel twice!\n",
> +		       __func__);

You should use dev_err, dev_warn and dev_info instead of printks using 
the dssdev->dev device.

Archit

> +		WARN_ON(1);
> +	}
> +}
> +
> +static int boxer_panel_suspend(struct omap_dss_device *dssdev)
> +{
> +	boxer_panel_disable(dssdev);
> +	return 0;
> +}
> +
> +static int boxer_panel_resume(struct omap_dss_device *dssdev)
> +{
> +	return boxer_panel_enable(dssdev);
> +}
> +
> +static struct omap_dss_driver boxer_driver = {
> +	.probe          = boxer_panel_probe,
> +	.remove         = boxer_panel_remove,
> +
> +	.enable         = boxer_panel_enable,
> +	.disable        = boxer_panel_disable,
> +	.suspend        = boxer_panel_suspend,
> +	.resume         = boxer_panel_resume,
> +	.get_resolution = boxer_get_resolution,
> +	.get_recommended_bpp = boxer_get_recommended_bpp,
> +	.driver		= {
> +		.name	= "boxer_panel",
> +		.owner	= THIS_MODULE,
> +	},
> +};
> +
> +static ssize_t lcd_reg_store(struct device *dev, struct device_attribute *attr,
> +			     const char *buf, size_t count)
> +{
> +	int argc;
> +	char **args;
> +	unsigned long r, val;
> +	int ret;
> +
> +	struct spi_device *spi = to_spi_device(dev);
> +
> +	args = argv_split(GFP_KERNEL, buf,&argc);
> +
> +	if (args == NULL) {
> +		dev_err(dev, "error getting arguments\n");
> +		return count;
> +	}
> +
> +	if (argc == 2) {
> +		ret = strict_strtoul(*args, 0, (unsigned long *)&r);
> +		if (ret)
> +			return ret;
> +		args++;
> +		ret = strict_strtoul(*args, 0, (unsigned long *)&val);
> +		if (ret)
> +			return ret;
> +		dev_info(dev, "set lcd panel spi reg %lu = %lu\n", r, val);
> +		spi_send(spi, r, val);
> +	}
> +	argv_free(args);
> +
> +	return count;
> +}
> +
> +
> +static DEVICE_ATTR(lcd_reg, S_IWUSR, NULL, lcd_reg_store);
> +
> +static struct attribute *boxer_lcd_spi_attributes[] = {
> +	&dev_attr_lcd_reg,
> +	NULL
> +};
> +
> +
> +static struct attribute_group boxer_lcd_spi_attributes_group = {
> +	.attrs = boxer_lcd_spi_attributes,
> +};
> +
> +
> +
> +static int boxer_spi_probe(struct spi_device *spi)
> +{
> +	spi->mode = SPI_MODE_0;
> +	spi->bits_per_word = 16;
> +	spi_setup(spi);
> +
> +	boxer_spi_device = spi;
> +
> +	boxer_init_panel();
> +
> +	if (sysfs_create_group(&spi->dev.kobj,&boxer_lcd_spi_attributes_group))
> +		printk(KERN_WARNING "error creating sysfs entries\n");
> +
> +	omap_dss_register_driver(&boxer_driver);
> +	return 0;
> +}
> +
> +static int boxer_spi_remove(struct spi_device *spi)
> +{
> +	sysfs_remove_group(&spi->dev.kobj,&boxer_lcd_spi_attributes_group);
> +	omap_dss_unregister_driver(&boxer_driver);
> +
> +	return 0;
> +}
> +
> +
> +static struct spi_driver boxer_spi_driver = {
> +	.probe           = boxer_spi_probe,
> +	.remove	= __devexit_p(boxer_spi_remove),
> +	.driver         = {
> +		.name   = "boxer_disp_spi",
> +		.bus    =&spi_bus_type,
> +		.owner  = THIS_MODULE,
> +	},
> +};
> +
> +static int __init boxer_lcd_init(void)
> +{
> +	int ret = 0;
> +
> +	boxer_panel_wq = create_singlethread_workqueue("boxer-panel-wq");
> +
> +	printk(KERN_WARNING "Enabling power for LCD\n");
> +	boxer_panel_regulator = regulator_get(NULL, "vlcd");
> +
> +	if (IS_ERR(boxer_panel_regulator)) {
> +		printk(KERN_ERR "Unable to get vlcd regulator, reason: %ld!\n",
> +		       IS_ERR(boxer_panel_regulator));
> +		ret = -ENODEV;
> +		goto out;
> +	}
> +
> +	ret = regulator_enable(boxer_panel_regulator);
> +
> +	if (ret) {
> +		printk(KERN_ERR "Failed to enable regulator vlcd!\n");
> +		regulator_put(boxer_panel_regulator);
> +		goto out;
> +	}
> +
> +	return spi_register_driver(&boxer_spi_driver);
> +out:
> +	return ret;
> +}
> +
> +static void __exit boxer_lcd_exit(void)
> +{
> +	spi_unregister_driver(&boxer_spi_driver);
> +	regulator_disable(boxer_panel_regulator);
> +	regulator_put(boxer_panel_regulator);
> +	destroy_workqueue(boxer_panel_wq);
> +}
> +
> +
> +module_init(boxer_lcd_init);
> +module_exit(boxer_lcd_exit);
> +MODULE_LICENSE("GPL");
> +