ENGR00298052-1 video: mxc: add Hannstar CABC driver

This patch adds Hannstar CABC driver support.  The CABC
function turns the backlight density of a display panel
automatically according to the content shown on the panel.
It is controlled(enabled/disabled) by a GPIO.

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>

3 files changed, 98 insertions, 0 deletions

diff --git a/drivers/video/mxc/Kconfig b/drivers/video/mxc/Kconfig
index 759ff096826c..2269de1e02cb 100644
--- a/drivers/video/mxc/Kconfig
+++ b/drivers/video/mxc/Kconfig
@@ -61,3 +61,11 @@ config FB_MXC_EINK_AUTO_UPDATE_MODE
 config FB_MXS_SII902X
         tristate "Si Image SII9022 DVI/HDMI Interface Chip"
         depends on FB_MXS && I2C
+
+config HANNSTAR_CABC
+        tristate "Hannstar CABC function"
+        help
+          Say yes here to support switching on/off Hannstar CABC
+          function.  This function turns backlight density of a
+          display panel automatically according to the content
+          shown on the panel.
diff --git a/drivers/video/mxc/Makefile b/drivers/video/mxc/Makefile
index 6a5b855dbafa..c0fec9e79727 100644
--- a/drivers/video/mxc/Makefile
+++ b/drivers/video/mxc/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_FB_MXC_EDID)			+= mxc_edid.o
 obj-$(CONFIG_FB_MXC_SYNC_PANEL) += mxc_dispdrv.o mxc_lcdif.o mxc_ipuv3_fb.o
 obj-$(CONFIG_FB_MXC_EINK_PANEL)             += mxc_epdc_fb.o
 obj-$(CONFIG_FB_MXS_SII902X) += mxsfb_sii902x.o
+obj-$(CONFIG_HANNSTAR_CABC) += hannstar_cabc.o
diff --git a/drivers/video/mxc/hannstar_cabc.c b/drivers/video/mxc/hannstar_cabc.c
new file mode 100644
index 000000000000..c1d8442948be
--- /dev/null
+++ b/drivers/video/mxc/hannstar_cabc.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2014 Freescale Semiconductor, Inc. All Rights Reserved.
+ *
+ * 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.
+
+ * 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.h>
+
+#define DRIVER_NAME "hannstar-cabc"
+
+static const struct of_device_id cabc_dt_ids[] = {
+        { .compatible = "hannstar,cabc", },
+        { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, cabc_dt_ids);
+
+static int cabc_probe(struct platform_device *pdev)
+{
+        struct device_node *np = pdev->dev.of_node, *pp;
+        int cabc_gpio, ret = 0;
+        bool cabc_enable;
+        unsigned long gpio_flag;
+        enum of_gpio_flags flags;
+
+        for_each_child_of_node(np, pp) {
+                if (!of_find_property(pp, "gpios", NULL)) {
+                        dev_warn(&pdev->dev, "Found interface without "
+                                 "gpios\n");
+                        continue;
+                }
+
+                cabc_gpio = of_get_gpio_flags(pp, 0, &flags);
+                if (!gpio_is_valid(cabc_gpio)) {
+                        ret = cabc_gpio;
+                        if (ret != -EPROBE_DEFER)
+                                dev_err(&pdev->dev,
+                                        "Failed to get gpio flags, "
+                                        "error: %d\n", ret);
+                        return ret;
+                }
+
+                cabc_enable = of_property_read_bool(pp, "cabc-enable");
+
+                if (flags & OF_GPIO_ACTIVE_LOW)
+                        gpio_flag = cabc_enable ?
+                                GPIOF_OUT_INIT_LOW : GPIOF_OUT_INIT_HIGH;
+                else
+                        gpio_flag = cabc_enable ?
+                                GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
+
+                devm_gpio_request_one(&pdev->dev, cabc_gpio,
+                                        gpio_flag, "hannstar-cabc");
+        }
+
+        return ret;
+}
+
+static struct platform_driver cabc_driver = {
+        .probe  = cabc_probe,
+        .driver = {
+                .of_match_table = cabc_dt_ids,
+                .name   = DRIVER_NAME,
+                .owner  = THIS_MODULE,
+        },
+};
+module_platform_driver(cabc_driver);
+
+MODULE_AUTHOR("Freescale Semiconductor, Inc.");
+MODULE_DESCRIPTION("Hannstar CABC driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);