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SubjectRe: [PATCH] Backlight driver for Tabletkiosk Sahara TouchIT-213 Tablet PC
Hi,

> Poking at random ports isn't very nice. Is it possible to autodetect
> this tablet PC ? Has it specific PCI ids or usefull DMI table ?

I didn't find anthing with lspci but can detect through DMI - if you are
interested you find the dmidecode output at the end of
http://claudio.ch/Bin/viewcvs.cgi/Config/sysinfo_touchIt213?rev=294 - and do it
in a similar way as in mbp_nvidia_bl.c. Have done it in the included patch.

Looking at the macbook driver I see it is much simpler and shorter than mine
which I derived from corgi_bl.c. No platform driver, no probe, remove, suspend
and resume.

Why is one much simpler than the other? Is functionality missing in the MacBook
driver or is the corgi one just (historically) overblown? If I could safely
reduce my driver to be as simple as the macbook one I would be more than happy
to do it.

> static ?

Fixed.

> Why do you need this wrapper ?

When I studied the corgi_bl driver I noticed that some stuff is done in the
driver itself and then there is the "platform stuff". I didn't know how to
handle it and was given the suggestion to put the platform stuff also in the
driver which I did but tried to keep that textually separate. Thus the separate
sahara_init. Yet I had to call it in kb3886_init otherwise nothing else would
do. I surely didn't fully understand what I was doing when I wrote that. Have
simplified it as suggested.

If all this can be simplified even more, like is done in macbook driver, that
would be great.

> This function is unused. Looks like you copied it from corgi_bl.c where
> it is called from platform code.

Fixed, i.e. removed.

Below the fixed patch, correcting all mistakes reported by Andrey.


Signed-off-by: Claudio Nieder <private@claudio.ch>

---
drivers/video/backlight/Kconfig | 7 +
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/kb3886_bl.c | 214 +++++++++++++++++++++++++++++++++++
3 files changed, 222 insertions(+), 0 deletions(-)

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 452b770..bc65541 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -164,3 +164,10 @@ config BACKLIGHT_MBP_NVIDIA
If you have an Apple Macbook Pro with Nvidia graphics hardware say Y
to enable a driver for its backlight

+config BACKLIGHT_SAHARA
+ tristate "Tabletkiosk Sahara Touch-iT Backlight Driver"
+ depends on BACKLIGHT_CLASS_DEVICE && X86
+ default y
+ help
+ If you have a Tabletkiosk Sahara Touch-iT, say y to enable the
+ backlight driver.
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index b405aac..f4a1183 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -16,4 +16,5 @@ obj-$(CONFIG_BACKLIGHT_PROGEAR) += progear_bl.o
obj-$(CONFIG_BACKLIGHT_CARILLO_RANCH) += cr_bllcd.o
obj-$(CONFIG_BACKLIGHT_PWM) += pwm_bl.o
obj-$(CONFIG_BACKLIGHT_MBP_NVIDIA) += mbp_nvidia_bl.o
+obj-$(CONFIG_BACKLIGHT_SAHARA) += kb3886_bl.o

diff --git a/drivers/video/backlight/kb3886_bl.c
b/drivers/video/backlight/kb3886_bl.c
new file mode 100644
index 0000000..1a1d8aa
--- /dev/null
+++ b/drivers/video/backlight/kb3886_bl.c
@@ -0,0 +1,214 @@
+/*
+ * Backlight Driver for the KB3886 Backlight
+ *
+ * Copyright (c) 2007-2008 Claudio Nieder
+ *
+ * Based on corgi_bl.c by Richard Purdie and kb3886 driver by Robert Woerle
+ *
+ * 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.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/mutex.h>
+#include <linux/fb.h>
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/dmi.h>
+
+/*
+ * The following is what corgi has in arch/arm/mach-pxa/corgi.c and
+ * corgi_lcd.c. On kernelnebwies it was suggested I put the platform_device
+ * code in my driver.
+ */
+
+#define KB3886_PARENT 0x64
+#define KB3886_IO 0x60
+#define KB3886_ADC_DAC_PWM 0xC4
+#define KB3886_PWM0_WRITE 0x81
+#define KB3886_PWM0_READ 0x41
+
+static DEFINE_MUTEX(bl_mutex);
+
+static void kb3886_bl_set_intensity(int intensity)
+{
+ mutex_lock(&bl_mutex);
+ intensity = intensity&0xff;
+ outb(KB3886_ADC_DAC_PWM, KB3886_PARENT);
+ msleep(10);
+ outb(KB3886_PWM0_WRITE, KB3886_IO);
+ msleep(10);
+ outb(intensity, KB3886_IO);
+ mutex_unlock(&bl_mutex);
+}
+
+struct kb3886bl_machinfo {
+ int max_intensity;
+ int default_intensity;
+ int limit_mask;
+ void (*set_bl_intensity)(int intensity);
+};
+
+static struct kb3886bl_machinfo kb3886_bl_machinfo = {
+ .max_intensity = 0xff,
+ .default_intensity = 0xa0,
+ .limit_mask = 0x7f,
+ .set_bl_intensity = kb3886_bl_set_intensity,
+};
+
+static struct platform_device kb3886bl_device = {
+ .name = "kb3886-bl",
+ .dev = {
+ .platform_data = &kb3886_bl_machinfo,
+ },
+ .id = -1,
+};
+
+static struct platform_device *devices[] __initdata = {
+ &kb3886bl_device,
+};
+
+/*
+ * Back to driver
+ */
+
+static int kb3886bl_intensity;
+static struct backlight_device *kb3886_backlight_device;
+static struct kb3886bl_machinfo *bl_machinfo;
+
+static unsigned long kb3886bl_flags;
+#define KB3886BL_SUSPENDED 0x01
+#define KB3886BL_BATTLOW 0x02
+
+static struct dmi_system_id __initdata kb3886bl_device_table[] = {
+ {
+ .ident = "Sahara Touch-iT",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "SDV"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "iTouch T201"),
+ },
+ },
+ { },
+ { },
+ { }
+};
+
+static int kb3886bl_send_intensity(struct backlight_device *bd)
+{
+ int intensity = bd->props.brightness;
+
+ if (bd->props.power != FB_BLANK_UNBLANK)
+ intensity = 0;
+ if (bd->props.fb_blank != FB_BLANK_UNBLANK)
+ intensity = 0;
+ if (kb3886bl_flags & KB3886BL_SUSPENDED)
+ intensity = 0;
+ if (kb3886bl_flags & KB3886BL_BATTLOW)
+ intensity &= bl_machinfo->limit_mask;
+
+ bl_machinfo->set_bl_intensity(intensity);
+
+ kb3886bl_intensity = intensity;
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int kb3886bl_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ struct backlight_device *bd = platform_get_drvdata(pdev);
+
+ kb3886bl_flags |= KB3886BL_SUSPENDED;
+ backlight_update_status(bd);
+ return 0;
+}
+
+static int kb3886bl_resume(struct platform_device *pdev)
+{
+ struct backlight_device *bd = platform_get_drvdata(pdev);
+
+ kb3886bl_flags &= ~KB3886BL_SUSPENDED;
+ backlight_update_status(bd);
+ return 0;
+}
+#else
+#define kb3886bl_suspend NULL
+#define kb3886bl_resume NULL
+#endif
+
+static int kb3886bl_get_intensity(struct backlight_device *bd)
+{
+ return kb3886bl_intensity;
+}
+
+static struct backlight_ops kb3886bl_ops = {
+ .get_brightness = kb3886bl_get_intensity,
+ .update_status = kb3886bl_send_intensity,
+};
+
+static int kb3886bl_probe(struct platform_device *pdev)
+{
+ struct kb3886bl_machinfo *machinfo = pdev->dev.platform_data;
+
+ bl_machinfo = machinfo;
+ if (!machinfo->limit_mask)
+ machinfo->limit_mask = -1;
+
+ kb3886_backlight_device = backlight_device_register("kb3886-bl",
+ &pdev->dev, NULL, &kb3886bl_ops);
+ if (IS_ERR (kb3886_backlight_device))
+ return PTR_ERR(kb3886_backlight_device);
+
+ platform_set_drvdata(pdev, kb3886_backlight_device);
+
+ kb3886_backlight_device->props.max_brightness = machinfo->max_intensity;
+ kb3886_backlight_device->props.power = FB_BLANK_UNBLANK;
+ kb3886_backlight_device->props.brightness = machinfo->default_intensity;
+ backlight_update_status(kb3886_backlight_device);
+
+ return 0;
+}
+
+static int kb3886bl_remove(struct platform_device *pdev)
+{
+ struct backlight_device *bd = platform_get_drvdata(pdev);
+
+ backlight_device_unregister(bd);
+
+ return 0;
+}
+
+static struct platform_driver kb3886bl_driver = {
+ .probe = kb3886bl_probe,
+ .remove = kb3886bl_remove,
+ .suspend = kb3886bl_suspend,
+ .resume = kb3886bl_resume,
+ .driver = {
+ .name = "kb3886-bl",
+ },
+};
+
+static int __init kb3886_init(void)
+{
+ if (!dmi_check_system(kb3886bl_device_table))
+ return -ENODEV;
+
+ platform_add_devices(devices, ARRAY_SIZE(devices));
+ return platform_driver_register(&kb3886bl_driver);
+}
+
+static void __exit kb3886_exit(void)
+{
+ platform_driver_unregister(&kb3886bl_driver);
+}
+
+module_init(kb3886_init);
+module_exit(kb3886_exit);
+
+MODULE_AUTHOR("Claudio Nieder <private@claudio.ch>");
+MODULE_DESCRIPTION("Tabletkiosk Sahara Touch-iT Backlight Driver");
+MODULE_LICENSE("GPL");
--
1.4.4.4
claudio
--
Claudio Nieder, Talweg 6, CH-8610 Uster, Tel +4179 357 6743, www.claudio.ch


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