[RFC/PATCH 2/2] backlight: mxs: Add backlight support for i.MX23
Gregory CLEMENT
gregory.clement at free-electrons.com
Thu Oct 6 04:05:16 EDT 2011
May work on i.MX28 but only tested on i.MX23 base board
Signed-off-by: Gregory CLEMENT <gregory.clement at free-electrons.com>
---
arch/arm/mach-mxs/include/mach/backlight.h | 19 ++++
drivers/video/backlight/Kconfig | 8 ++
drivers/video/backlight/Makefile | 4 +-
drivers/video/backlight/backlight-mxs.c | 136 ++++++++++++++++++++++++++++
4 files changed, 166 insertions(+), 1 deletions(-)
create mode 100644 arch/arm/mach-mxs/include/mach/backlight.h
create mode 100644 drivers/video/backlight/backlight-mxs.c
diff --git a/arch/arm/mach-mxs/include/mach/backlight.h b/arch/arm/mach-mxs/include/mach/backlight.h
new file mode 100644
index 0000000..7afc165
--- /dev/null
+++ b/arch/arm/mach-mxs/include/mach/backlight.h
@@ -0,0 +1,19 @@
+/*
+ * backlight.h - plateform definitions for the mxs backlight driver
+ *
+ * Copyright (C) 2011 Gregory Clement, Free Electrons
+ *
+ * This file is released under the GPLv2 or later
+ *
+ */
+
+#ifndef BACKLIGHT_MXS_H
+#define BACKLIGHT_MXS_H
+
+struct mxs_backlight_platformdata {
+ int channel;
+ int period;
+ int cdiv;
+};
+
+#endif /* BACKLIGHT__H */
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index b593a82..9a8d2e1 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -6,3 +6,11 @@ menuconfig BACKLIGHT
bool "Backlight support"
help
Add support for backlight
+
+if BACKLIGHT
+
+config BACKLIGHT_MXS
+ bool "i.MX23 Backlight driver"
+ depends on BACKLIGHT && ARCH_MXS
+
+endif
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 3c63230..fe97ac6 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -1 +1,3 @@
-obj-$(CONFIG_BACKLIGHT) += backlight.o
\ No newline at end of file
+obj-$(CONFIG_BACKLIGHT) += backlight.o
+
+obj-$(CONFIG_BACKLIGHT_MSX) += backlight-mxs.o
diff --git a/drivers/video/backlight/backlight-mxs.c b/drivers/video/backlight/backlight-mxs.c
new file mode 100644
index 0000000..e33f45f
--- /dev/null
+++ b/drivers/video/backlight/backlight-mxs.c
@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2011 Gregory Clement, Free Electrons
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+ * USA.
+ *
+ */
+#include <clock.h>
+#include <common.h>
+#include <driver.h>
+#include <init.h>
+#include <malloc.h>
+#include <types.h>
+#include <backlight.h>
+
+#include <asm/io.h>
+#include <mach/clock.h>
+#include <mach/backlight.h>
+
+/* This will be the driver name */
+#define DRIVER_NAME "mxs-backlight"
+
+#define HW_PWM_CTRL_SFTRST 0x80000000
+#define HW_PWM_CTRL_CLKGATE 0x40000000
+#define SET 0x4
+#define CLR 0x8
+#define HW_PWM_ACTIVEn(n) (0x00000010 + (n) * 0x20)
+#define BP_PWM_ACTIVEn_INACTIVE 16
+#define BM_PWM_ACTIVEn_INACTIVE 0xFFFF0000
+#define BF_PWM_ACTIVEn_INACTIVE(v) \
+ (((v) << 16) & BM_PWM_ACTIVEn_INACTIVE)
+#define BM_PWM_ACTIVEn_ACTIVE 0x0000FFFF
+#define BF_PWM_ACTIVEn_ACTIVE(v) \
+ (((v) << 0) & BM_PWM_ACTIVEn_ACTIVE)
+
+#define HW_PWM_PERIODn(n) (0x00000020 + (n) * 0x20)
+#define BM_PWM_PERIODn_CDIV 0x00700000
+#define BF_PWM_PERIODn_CDIV(v) \
+ (((v) << 20) & BM_PWM_PERIODn_CDIV)
+#define BM_PWM_PERIODn_INACTIVE_STATE 0x000C0000
+#define BF_PWM_PERIODn_INACTIVE_STATE(v) \
+ (((v) << 18) & BM_PWM_PERIODn_INACTIVE_STATE)
+#define BM_PWM_PERIODn_ACTIVE_STATE 0x00030000
+#define BF_PWM_PERIODn_ACTIVE_STATE(v) \
+ (((v) << 16) & BM_PWM_PERIODn_ACTIVE_STATE)
+#define BM_PWM_PERIODn_PERIOD 0x0000FFFF
+#define BF_PWM_PERIODn_PERIOD(v) \
+ (((v) << 0) & BM_PWM_PERIODn_PERIOD)
+#define BM_PWM_CTRL_PWM4_ENABLE 0x00000010
+#define BM_PWM_CTRL_PWM3_ENABLE 0x00000008
+#define BM_PWM_CTRL_PWM2_ENABLE 0x00000004
+#define BM_PWM_CTRL_PWM1_ENABLE 0x00000002
+#define BM_PWM_CTRL_PWM0_ENABLE 0x00000001
+
+struct backlight_mxs_struct {
+ void __iomem *base;
+ struct device_d *hw_dev; /* Pointer on hw backlight device */
+ struct backlight_dev backlight;
+ struct mxs_backlight_platformdata *pdata;
+};
+
+int backlight_mxs_set_brightness(struct backlight_dev *backlight, int percent)
+{
+ struct backlight_mxs_struct *backlight_mxs = backlight->priv;
+ struct mxs_backlight_platformdata *pdata = backlight_mxs->pdata;
+
+ if (percent > 100)
+ percent = 100;
+
+ writel(BF_PWM_ACTIVEn_INACTIVE((pdata->period * percent) / 200) |
+ /* backlight intensity */
+ BF_PWM_ACTIVEn_ACTIVE(0),
+ backlight_mxs->base + HW_PWM_ACTIVEn(pdata->channel));
+ writel(BF_PWM_PERIODn_CDIV(pdata->cdiv) | /* divide by 2^cdiv */
+ BF_PWM_PERIODn_INACTIVE_STATE(2) | /* low */
+ BF_PWM_PERIODn_ACTIVE_STATE(3) | /* high */
+ BF_PWM_PERIODn_PERIOD(pdata->period - 1),
+ backlight_mxs->base + HW_PWM_PERIODn(pdata->channel));
+ writel(1 << pdata->channel, backlight_mxs->base + SET);
+
+ return percent;
+}
+
+static int __init backlight_mxs_probe(struct device_d *pdev)
+{
+ struct backlight_mxs_struct *backlight_mxs;
+
+ backlight_mxs =
+ kzalloc(sizeof(struct backlight_mxs_struct), GFP_KERNEL);
+
+ /* Setup backlight_mxs driver structure */
+ backlight_mxs->hw_dev = pdev;
+ backlight_mxs->pdata = pdev->platform_data;
+ backlight_mxs->hw_dev->priv = backlight_mxs;
+ backlight_mxs->base = dev_request_mem_region(pdev, 0);
+ backlight_mxs->backlight.set_brightness = backlight_mxs_set_brightness;
+ backlight_mxs->backlight.priv = backlight_mxs;
+
+ imx_enable_pwnclk();
+ /* Reset PWM module */
+ writel(HW_PWM_CTRL_SFTRST, backlight_mxs->base + SET);
+ udelay(100);
+ /* Remove CLKGATE and SFTRST */
+ writel(HW_PWM_CTRL_SFTRST, backlight_mxs->base + CLR);
+ udelay(100);
+ writel(HW_PWM_CTRL_CLKGATE, backlight_mxs->base + CLR);
+ udelay(100);
+
+ register_backlight(&backlight_mxs->backlight);
+
+ return 0;
+}
+
+static struct driver_d backlight_mxs_driver = {
+ .probe = backlight_mxs_probe,
+ .name = DRIVER_NAME,
+};
+
+static int __init backlight_mxs_init(void)
+{
+ return register_driver(&backlight_mxs_driver);
+}
+
+device_initcall(backlight_mxs_init);
--
1.7.4.1
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