[PATCH 2/3] backlight: aat2870: Add AAT2870 backlight driver

Jin Park
2011-06-29T14:07:03Z

Add backlight driver for AnalogicTech AAT2870.

Signed-off-by: Jin Park <jinyoungp@nvidia.com>
---
drivers/video/backlight/Kconfig | 7 +
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/aat2870_bl.c | 246 ++++++++++++++++++++++++++++++++++
3 files changed, 254 insertions(+), 0 deletions(-)
create mode 100644 drivers/video/backlight/aat2870_bl.c

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 2d93c8d..07ce8f0 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -327,6 +327,13 @@ config BACKLIGHT_PCF50633
If you have a backlight driven by a NXP PCF50633 MFD, say Y here to
enable its driver.

+config BACKLIGHT_AAT2870
+ bool "AnalogicTech AAT2870 Backlight"
+ depends on BACKLIGHT_CLASS_DEVICE && MFD_AAT2870_CORE
+ help
+ If you have a AnalogicTech AAT2870 say Y to enable the
+ backlight driver.
+
endif # BACKLIGHT_CLASS_DEVICE

endif # BACKLIGHT_LCD_SUPPORT
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index ee72adb..27f99d1 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -37,4 +37,5 @@ obj-$(CONFIG_BACKLIGHT_ADP8860) += adp8860_bl.o
obj-$(CONFIG_BACKLIGHT_ADP8870) += adp8870_bl.o
obj-$(CONFIG_BACKLIGHT_88PM860X) += 88pm860x_bl.o
obj-$(CONFIG_BACKLIGHT_PCF50633) += pcf50633-backlight.o
+obj-$(CONFIG_BACKLIGHT_AAT2870) += aat2870_bl.o

diff --git a/drivers/video/backlight/aat2870_bl.c b/drivers/video/backlight/aat2870_bl.c
new file mode 100644
index 0000000..4952a61
--- /dev/null
+++ b/drivers/video/backlight/aat2870_bl.c
@@ -0,0 +1,246 @@
+/*
+ * linux/drivers/video/backlight/aat2870_bl.c
+ *
+ * Copyright (c) 2011, NVIDIA Corporation.
+ * Author: Jin Park <jinyoungp@nvidia.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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/fb.h>
+#include <linux/backlight.h>
+#include <linux/mfd/aat2870.h>
+
+struct aat2870_bl_driver_data {
+ struct platform_device *pdev;
+ struct backlight_device *bd;
+
+ int channels;
+ int max_current;
+ int brightness; /* current brightness */
+};
+
+static inline int aat2870_brightness(struct aat2870_bl_driver_data *aat2870_bl,
+ int brightness)
+{
+ struct backlight_device *bd = aat2870_bl->bd;
+ int val;
+
+ val = brightness * aat2870_bl->max_current;
+ val /= bd->props.max_brightness;
+
+ return val;
+}
+
+static inline int aat2870_bl_enable(struct aat2870_bl_driver_data *aat2870_bl)
+{
+ struct aat2870_data *aat2870
+ = dev_get_drvdata(aat2870_bl->pdev->dev.parent);
+
+ return aat2870->write(aat2870, AAT2870_BL_CH_EN,
+ (u8)aat2870_bl->channels);
+}
+
+static inline int aat2870_bl_disable(struct aat2870_bl_driver_data *aat2870_bl)
+{
+ struct aat2870_data *aat2870
+ = dev_get_drvdata(aat2870_bl->pdev->dev.parent);
+
+ return aat2870->write(aat2870, AAT2870_BL_CH_EN, 0x0);
+}
+
+static int aat2870_bl_get_brightness(struct backlight_device *bd)
+{
+ return bd->props.brightness;
+}
+
+static int aat2870_bl_update_status(struct backlight_device *bd)
+{
+ struct aat2870_bl_driver_data *aat2870_bl = dev_get_drvdata(&bd->dev);
+ struct aat2870_data *aat2870 =
+ dev_get_drvdata(aat2870_bl->pdev->dev.parent);
+ int brightness = bd->props.brightness;
+ int ret;
+
+ if ((brightness < 0) || (bd->props.max_brightness < brightness)) {
+ dev_err(&bd->dev, "invalid brightness, %d\n", brightness);
+ return -EINVAL;
+ }
+
+ dev_dbg(&bd->dev, "brightness=%d, power=%d, state=%d\n",
+ bd->props.brightness, bd->props.power, bd->props.state);
+
+ if ((bd->props.power != FB_BLANK_UNBLANK) ||
+ (bd->props.state & BL_CORE_FBBLANK) ||
+ (bd->props.state & BL_CORE_SUSPENDED))
+ brightness = 0;
+
+ ret = aat2870->write(aat2870, AAT2870_BLM,
+ (u8)aat2870_brightness(aat2870_bl, brightness));
+ if (ret < 0)
+ return ret;
+
+ if (brightness == 0) {
+ ret = aat2870_bl_disable(aat2870_bl);
+ if (ret < 0)
+ return ret;
+ } else if (aat2870_bl->brightness == 0) {
+ ret = aat2870_bl_enable(aat2870_bl);
+ if (ret < 0)
+ return ret;
+ }
+
+ aat2870_bl->brightness = brightness;
+
+ return 0;
+}
+
+static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
+{
+ return 1;
+}
+
+static const struct backlight_ops aat2870_bl_ops = {
+ .options = BL_CORE_SUSPENDRESUME,
+ .get_brightness = aat2870_bl_get_brightness,
+ .update_status = aat2870_bl_update_status,
+ .check_fb = aat2870_bl_check_fb,
+};
+
+static int aat2870_bl_probe(struct platform_device *pdev)
+{
+ struct aat2870_bl_platform_data *pdata = pdev->dev.platform_data;
+ struct aat2870_bl_driver_data *aat2870_bl;
+ struct backlight_device *bd;
+ struct backlight_properties props;
+ int ret = 0;
+
+ if (!pdata) {
+ dev_err(&pdev->dev, "No platform data\n");
+ ret = -ENXIO;
+ goto out;
+ }
+
+ if (pdev->id != AAT2870_ID_BL) {
+ dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ aat2870_bl = kzalloc(sizeof(struct aat2870_bl_driver_data), GFP_KERNEL);
+ if (!aat2870_bl) {
+ dev_err(&pdev->dev,
+ "Failed to allocate memory for aat2870 backlight\n");
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ memset(&props, 0, sizeof(struct backlight_properties));
+
+ props.type = BACKLIGHT_RAW;
+ bd = backlight_device_register("aat2870-backlight", &pdev->dev,
+ aat2870_bl, &aat2870_bl_ops, &props);
+ if (!bd) {
+ dev_err(&pdev->dev,
+ "Failed allocate memory for backlight device\n");
+ ret = -ENOMEM;
+ goto out_kfree;
+ }
+
+ aat2870_bl->pdev = pdev;
+ platform_set_drvdata(pdev, aat2870_bl);
+
+ aat2870_bl->bd = bd;
+
+ if (pdata->channels > 0)
+ aat2870_bl->channels = pdata->channels;
+ else
+ aat2870_bl->channels = AAT2870_BL_CH_ALL;
+
+ if (pdata->max_brightness > 0)
+ aat2870_bl->max_current = pdata->max_current;
+ else
+ aat2870_bl->max_current = AAT2870_CURRENT_27_9;
+
+ if (pdata->max_brightness > 0)
+ bd->props.max_brightness = pdata->max_brightness;
+ else
+ bd->props.max_brightness = 255;
+
+ aat2870_bl->brightness = 0;
+ bd->props.power = FB_BLANK_UNBLANK;
+ bd->props.brightness = bd->props.max_brightness;
+
+ ret = aat2870_bl_update_status(bd);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to initialize\n");
+ goto out_bl_dev_unregister;
+ }
+
+ return 0;
+
+out_bl_dev_unregister:
+ backlight_device_unregister(bd);
+out_kfree:
+ kfree(aat2870_bl);
+out:
+ return ret;
+}
+
+static int aat2870_bl_remove(struct platform_device *pdev)
+{
+ struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev);
+ struct backlight_device *bd = aat2870_bl->bd;
+
+ bd->props.power = FB_BLANK_POWERDOWN;
+ bd->props.brightness = 0;
+ backlight_update_status(bd);
+
+ backlight_device_unregister(bd);
+ kfree(aat2870_bl);
+
+ return 0;
+}
+
+static struct platform_driver aat2870_bl_driver = {
+ .driver = {
+ .name = "aat2870-backlight",
+ .owner = THIS_MODULE,
+ },
+ .probe = aat2870_bl_probe,
+ .remove = aat2870_bl_remove,
+};
+
+static int __init aat2870_bl_init(void)
+{
+ return platform_driver_register(&aat2870_bl_driver);
+}
+subsys_initcall(aat2870_bl_init);
+
+static void __exit aat2870_bl_exit(void)
+{
+ platform_driver_unregister(&aat2870_bl_driver);
+}
+module_exit(aat2870_bl_exit);
+
+MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");
--
1.7.1