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Subject[PATCH v3 1/9] leds: add TI LMU backlight driver
Date
From: Pavel Machek <pavel@ucw.cz>

This adds backlight support for the following TI LMU
chips: LM3532, LM3631, LM3632, LM3633, LM3695 and LM3697.

It controls LEDs on Droid 4
smartphone, including keyboard and screen backlights.

Signed-off-by: Milo Kim <milo.kim@ti.com>
[add LED subsystem support for keyboard backlight and rework DT
binding according to Rob Herrings feedback]
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
[remove backlight subsystem support for now]
Signed-off-by: Pavel Machek <pavel@ucw.cz>
---
drivers/leds/Kconfig | 8 ++
drivers/leds/Makefile | 1 +
drivers/leds/ti-lmu-led-common.c | 138 ++++++++++++++++++++++++++++++
include/linux/ti-lmu-led-common.h | 59 +++++++++++++
4 files changed, 206 insertions(+)
create mode 100644 drivers/leds/ti-lmu-led-common.c
create mode 100644 include/linux/ti-lmu-led-common.h

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 44097a3e0fcc..dc717b30d9d3 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -756,6 +756,14 @@ config LEDS_NIC78BX
To compile this driver as a module, choose M here: the module
will be called leds-nic78bx.

+config LEDS_TI_LMU_COMMON
+ tristate "LED driver for TI LMU"
+ depends on REGMAP
+ help
+ Say Y to enable the LED driver for TI LMU devices.
+ This supports common features between the TI LM3532, LM3631, LM3632,
+ LM3633, LM3695 and LM3697.
+
comment "LED Triggers"
source "drivers/leds/trigger/Kconfig"

diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 420b5d2cfa62..e09bb27bc7ea 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -78,6 +78,7 @@ obj-$(CONFIG_LEDS_MT6323) += leds-mt6323.o
obj-$(CONFIG_LEDS_LM3692X) += leds-lm3692x.o
obj-$(CONFIG_LEDS_SC27XX_BLTC) += leds-sc27xx-bltc.o
obj-$(CONFIG_LEDS_LM3601X) += leds-lm3601x.o
+obj-$(CONFIG_LEDS_TI_LMU_COMMON) += ti-lmu-led-common.o

# LED SPI Drivers
obj-$(CONFIG_LEDS_CR0014114) += leds-cr0014114.o
diff --git a/drivers/leds/ti-lmu-led-common.c b/drivers/leds/ti-lmu-led-common.c
new file mode 100644
index 000000000000..a4435bd1d248
--- /dev/null
+++ b/drivers/leds/ti-lmu-led-common.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2015 Texas Instruments
+ * Copyright 2018 Sebastian Reichel
+ * Copyright 2018 Pavel Machek <pavel@ucw.cz>
+ *
+ * TI LMU Led driver, based on previous work from
+ * Milo Kim <milo.kim@ti.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/notifier.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+#include <linux/ti-lmu-led-common.h>
+
+const static int ramp_table[16] = { 2, 262, 524, 1049, 2090, 4194, 8389,
+ 16780, 33550, 41940, 50330, 58720,
+ 67110, 83880, 100660, 117440};
+
+static int ti_lmu_common_update_brightness_register(struct ti_lmu_bank *lmu_bank,
+ int brightness)
+{
+ struct regmap *regmap = lmu_bank->regmap;
+ u8 reg, val;
+ int ret;
+
+ /*
+ * Brightness register update
+ *
+ * 11 bit dimming: update LSB bits and write MSB byte.
+ * MSB brightness should be shifted.
+ * 8 bit dimming: write MSB byte.
+ */
+ if (lmu_bank->max_brightness == MAX_BRIGHTNESS_11BIT) {
+ reg = lmu_bank->lsb_brightness_reg;
+ ret = regmap_update_bits(regmap, reg,
+ LMU_11BIT_LSB_MASK,
+ brightness);
+ if (ret)
+ return ret;
+
+ val = brightness >> LMU_11BIT_MSB_SHIFT;
+ } else {
+ val = brightness;
+ }
+
+ reg = lmu_bank->msb_brightness_reg;
+
+ return regmap_write(regmap, reg, val);
+}
+
+int ti_lmu_common_set_brightness(struct ti_lmu_bank *lmu_bank,
+ int brightness)
+{
+ lmu_bank->current_brightness = brightness;
+
+ return ti_lmu_common_update_brightness_register(lmu_bank, brightness);
+}
+EXPORT_SYMBOL(ti_lmu_common_set_brightness);
+
+static int ti_lmu_common_convert_ramp_to_index(unsigned int msec)
+{
+ int size = ARRAY_SIZE(ramp_table);
+ int i;
+
+ if (msec <= ramp_table[0])
+ return 0;
+
+ if (msec > ramp_table[size - 1])
+ return size - 1;
+
+ for (i = 1; i < size; i++) {
+ if (msec == ramp_table[i])
+ return i;
+
+ /* Find an approximate index by looking up the table */
+ if (msec > ramp_table[i - 1] && msec < ramp_table[i]) {
+ if (msec - ramp_table[i - 1] < ramp_table[i] - msec)
+ return i - 1;
+ else
+ return i;
+ }
+ }
+
+ return -EINVAL;
+}
+
+int ti_lmu_common_set_ramp(struct ti_lmu_bank *lmu_bank)
+{
+ struct regmap *regmap = lmu_bank->regmap;
+ u8 ramp, ramp_up, ramp_down;
+
+ if (lmu_bank->ramp_up_msec == 0 && lmu_bank->ramp_down_msec == 0) {
+ ramp_up = 0;
+ ramp_down = 0;
+ } else {
+ ramp_up = ti_lmu_common_convert_ramp_to_index(lmu_bank->ramp_up_msec);
+ ramp_down = ti_lmu_common_convert_ramp_to_index(lmu_bank->ramp_down_msec);
+ }
+
+ if (ramp_up < 0 || ramp_down < 0)
+ return -EINVAL;
+
+ ramp = (ramp_up << 4) | ramp_down;
+
+ return regmap_write(regmap, lmu_bank->runtime_ramp_reg, ramp);
+
+}
+EXPORT_SYMBOL(ti_lmu_common_set_ramp);
+
+int ti_lmu_common_get_ramp_params(struct device *dev,
+ struct fwnode_handle *child,
+ struct ti_lmu_bank *lmu_data)
+{
+ int ret;
+
+ ret = fwnode_property_read_u32(child, "ramp-up-ms",
+ &lmu_data->ramp_up_msec);
+ if (ret)
+ dev_warn(dev, "ramp-up-ms property missing\n");
+
+
+ ret = fwnode_property_read_u32(child, "ramp-down-ms",
+ &lmu_data->ramp_down_msec);
+ if (ret)
+ dev_warn(dev, "ramp-down-ms property missing\n");
+
+ return 0;
+}
+EXPORT_SYMBOL(ti_lmu_common_get_ramp_params);
+
+MODULE_DESCRIPTION("TI LMU LED Driver");
+MODULE_AUTHOR("Sebastian Reichel");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:ti-lmu-led");
diff --git a/include/linux/ti-lmu-led-common.h b/include/linux/ti-lmu-led-common.h
new file mode 100644
index 000000000000..b0fe08f05be2
--- /dev/null
+++ b/include/linux/ti-lmu-led-common.h
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0
+// TI LMU Common Core
+// Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
+
+#ifndef _TI_LMU_COMMON_H_
+#define _TI_LMU_COMMON_H_
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <uapi/linux/uleds.h>
+
+#define LMU_DUAL_CHANNEL_USED (BIT(0) | BIT(1))
+#define LMU_11BIT_LSB_MASK (BIT(0) | BIT(1) | BIT(2))
+#define LMU_11BIT_MSB_SHIFT 3
+
+#define MAX_BRIGHTNESS_8BIT 255
+#define MAX_BRIGHTNESS_11BIT 2047
+
+#define NUM_DUAL_CHANNEL 2
+
+struct ti_lmu_bank {
+ struct regmap *regmap;
+
+ int bank_id;
+ int fault_monitor_used;
+
+ u8 enable_reg;
+ unsigned long enable_usec;
+
+ int current_brightness;
+ u32 default_brightness;
+ int max_brightness;
+
+ u8 lsb_brightness_reg;
+ u8 msb_brightness_reg;
+
+ u8 runtime_ramp_reg;
+ u32 ramp_up_msec;
+ u32 ramp_down_msec;
+};
+
+
+int ti_lmu_common_set_brightness(struct ti_lmu_bank *lmu_bank,
+ int brightness);
+
+int ti_lmu_common_set_ramp(struct ti_lmu_bank *lmu_bank);
+
+int ti_lmu_common_get_ramp_params(struct device *dev,
+ struct fwnode_handle *child,
+ struct ti_lmu_bank *lmu_data);
+
+#endif /* _TI_LMU_COMMON_H_ */
--
2.19.0
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