Cc'ing Daniel Thompson, the new Maintainer. On Fri, 27 Jan 2017, Olimpiu Dejeu wrote:
> backlight: Add support for Arctic Sand LED backlight driver chips > This driver provides support for the Arctic Sand arc2c0608 chip, > and provides a framework to support future devices. > Signed-off-by: Olimpiu Dejeu <olim...@arcticsand.com> > --- > > v3 => v4: > - Code style changes per Joe Perches and Jingoo Han > v2 => v3: > - Renamed variables to comply with conventions on naming > - Corrected device name in arcxcnn.h > v1 => v2: > - Removed "magic numbers" to initialize registers > - Cleaned up device tree bindings > - Fixed code style to address comments and pass "checkpatch" > - Removed unneeded debug and testing code > > drivers/video/backlight/Kconfig | 7 + > drivers/video/backlight/Makefile | 1 + > drivers/video/backlight/arcxcnn_bl.c | 452 > +++++++++++++++++++++++++++++++++++ > include/linux/i2c/arcxcnn.h | 51 ++++ > 4 files changed, 511 insertions(+) > create mode 100644 drivers/video/backlight/arcxcnn_bl.c > create mode 100644 include/linux/i2c/arcxcnn.h > > diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig > index 5ffa4b4..4e1d2ad 100644 > --- a/drivers/video/backlight/Kconfig > +++ b/drivers/video/backlight/Kconfig > @@ -460,6 +460,13 @@ config BACKLIGHT_BD6107 > help > If you have a Rohm BD6107 say Y to enable the backlight driver. > > +config BACKLIGHT_ARCXCNN > + tristate "Backlight driver for the Arctic Sands ARCxCnnnn family" > + depends on I2C > + help > + If you have an ARCxCnnnn family backlight 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 16ec534..8905129 100644 > --- a/drivers/video/backlight/Makefile > +++ b/drivers/video/backlight/Makefile > @@ -55,3 +55,4 @@ obj-$(CONFIG_BACKLIGHT_SKY81452) += sky81452-backlight.o > obj-$(CONFIG_BACKLIGHT_TOSA) += tosa_bl.o > obj-$(CONFIG_BACKLIGHT_TPS65217) += tps65217_bl.o > obj-$(CONFIG_BACKLIGHT_WM831X) += wm831x_bl.o > +obj-$(CONFIG_BACKLIGHT_ARCXCNN) += arcxcnn_bl.o > diff --git a/drivers/video/backlight/arcxcnn_bl.c > b/drivers/video/backlight/arcxcnn_bl.c > new file mode 100644 > index 0000000..284df08 > --- /dev/null > +++ b/drivers/video/backlight/arcxcnn_bl.c > @@ -0,0 +1,452 @@ > +/* > + * Backlight driver for ArcticSand ARC_X_C_0N_0N Devices > + * > + * Copyright 2016 ArcticSand, Inc. > + * Author : Brian Dodge <bdo...@arcticsand.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, see <http://www.gnu.org/licenses/>. > + */ > + > +#include <linux/backlight.h> > +#include <linux/err.h> > +#include <linux/i2c.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/slab.h> > + > +#include "linux/i2c/arcxcnn.h" > + > +#define ARCXCNN_CMD 0x00 /* Command Register */ > +#define ARCXCNN_CMD_STDBY 0x80 /* I2C Standby */ > +#define ARCXCNN_CMD_RESET 0x40 /* Reset */ > +#define ARCXCNN_CMD_BOOST 0x10 /* Boost */ > +#define ARCXCNN_CMD_OVP_MASK 0x0C /* --- Over Voltage Threshold */ > +#define ARCXCNN_CMD_OVP_XXV 0x0C /* <rsvrd> Over Voltage Threshold */ > +#define ARCXCNN_CMD_OVP_20V 0x08 /* 20v Over Voltage Threshold */ > +#define ARCXCNN_CMD_OVP_24V 0x04 /* 24v Over Voltage Threshold */ > +#define ARCXCNN_CMD_OVP_31V 0x00 /* 31.4v Over Voltage Threshold */ > +#define ARCXCNN_CMD_EXT_COMP 0x01 /* part (0) or full (1) ext. comp */ > + > +#define ARCXCNN_CONFIG 0x01 /* Configuration */ > +#define ARCXCNN_STATUS1 0x02 /* Status 1 */ > +#define ARCXCNN_STATUS2 0x03 /* Status 2 */ > +#define ARCXCNN_FADECTRL 0x04 /* Fading Control */ > +#define ARCXCNN_ILED_CONFIG 0x05 /* ILED Configuration */ > +#define ARCXCNN_ILED_DIM_PWM 0x00 /* config dim mode pwm */ > +#define ARCXCNN_ILED_DIM_INT 0x04 /* config dim mode internal */ > +#define ARCXCNN_LEDEN 0x06 /* LED Enable Register */ > +#define ARCXCNN_LEDEN_ISETEXT 0x80 /* Full-scale current set > extern */ > +#define ARCXCNN_LEDEN_MASK 0x3F /* LED string enables mask */ > +#define ARCXCNN_LEDEN_BITS 0x06 /* Bits of LED string enables */ > +#define ARCXCNN_LEDEN_LED1 0x01 > +#define ARCXCNN_LEDEN_LED2 0x02 > +#define ARCXCNN_LEDEN_LED3 0x04 > +#define ARCXCNN_LEDEN_LED4 0x08 > +#define ARCXCNN_LEDEN_LED5 0x10 > +#define ARCXCNN_LEDEN_LED6 0x20 > + > +#define ARCXCNN_WLED_ISET_LSB 0x07 /* LED ISET LSB (in upper > nibble) */ > +#define ARCXCNN_WLED_ISET_LSB_SHIFT 0x04 /* ISET LSB Left Shift */ > +#define ARCXCNN_WLED_ISET_MSB 0x08 /* LED ISET MSB (8 bits) */ > + > +#define ARCXCNN_DIMFREQ 0x09 > +#define ARCXCNN_COMP_CONFIG 0x0A > +#define ARCXCNN_FILT_CONFIG 0x0B > +#define ARCXCNN_IMAXTUNE 0x0C > +#define ARCXCNN_ID_MSB 0x1E > +#define ARCXCNN_ID_LSB 0x1F > + > +#define MAX_BRIGHTNESS 4095 > + > +static int s_no_reset_on_remove; > +module_param_named(noreset, s_no_reset_on_remove, int, 0644); > +MODULE_PARM_DESC(noreset, "No reset on module removal"); > + > +static int s_ibright = 60; > +module_param_named(ibright, s_ibright, int, 0644); > +MODULE_PARM_DESC(ibright, "Initial brightness (when no plat data)"); > + > +static int s_ileden = ARCXCNN_LEDEN_MASK; > +module_param_named(ileden, s_ileden, int, 0644); > +MODULE_PARM_DESC(ileden, "Initial LED String Enables (when no plat data)"); > + > +struct arcxcnn { > + char chipname[64]; > + struct i2c_client *client; > + struct backlight_device *bl; > + struct device *dev; > + struct arcxcnn_platform_data *pdata; > +}; > + > +static int arcxcnn_update_bit(struct arcxcnn *lp, u8 reg, u8 mask, u8 data) > +{ > + int ret; > + u8 tmp; > + > + ret = i2c_smbus_read_byte_data(lp->client, reg); > + if (ret < 0) { > + dev_err(lp->dev, "failed to read 0x%.2x\n", reg); > + return ret; > + } > + > + tmp = (u8)ret; > + tmp &= ~mask; > + tmp |= data & mask; > + > + return i2c_smbus_write_byte_data(lp->client, reg, tmp); > +} > + > +static int arcxcnn_set_brightness(struct arcxcnn *lp, u32 brightness) > +{ > + int ret; > + u8 val; > + > + /* lower nibble of brightness goes in upper nibble of LSB register */ > + val = (brightness & 0xF) << ARCXCNN_WLED_ISET_LSB_SHIFT; > + ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_WLED_ISET_LSB, val); > + if (ret < 0) > + return ret; > + > + /* remaining 8 bits of brightness go in MSB register */ > + val = (brightness >> 4); > + ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_WLED_ISET_MSB, val); > + > + return ret; > +} > + > +static int arcxcnn_bl_update_status(struct backlight_device *bl) > +{ > + struct arcxcnn *lp = bl_get_data(bl); > + u32 brightness = bl->props.brightness; > + > + if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK)) > + brightness = 0; > + > + arcxcnn_set_brightness(lp, brightness); > + > + /* set power-on/off/save modes */ > + arcxcnn_update_bit(lp, ARCXCNN_CMD, ARCXCNN_CMD_STDBY, > + (bl->props.power == 0) ? 0 : ARCXCNN_CMD_STDBY); > + > + return 0; > +} > + > +static const struct backlight_ops arcxcnn_bl_ops = { > + .options = BL_CORE_SUSPENDRESUME, > + .update_status = arcxcnn_bl_update_status, > +}; > + > +static int arcxcnn_backlight_register(struct arcxcnn *lp) > +{ > + struct backlight_properties *props; > + const char *name = lp->pdata->name ? : "arctic_bl"; > + > + props = devm_kzalloc(lp->dev, sizeof(*props), GFP_KERNEL); > + if (!props) > + return -ENOMEM; > + > + props->type = BACKLIGHT_PLATFORM; > + props->max_brightness = MAX_BRIGHTNESS; > + > + if (lp->pdata->initial_brightness > props->max_brightness) > + lp->pdata->initial_brightness = props->max_brightness; > + > + props->brightness = lp->pdata->initial_brightness; > + > + lp->bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp, > + &arcxcnn_bl_ops, props); > + if (IS_ERR(lp->bl)) > + return PTR_ERR(lp->bl); > + > + return 0; > +} > + > +static ssize_t arcxcnn_chip_id_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct arcxcnn *lp = dev_get_drvdata(dev); > + > + return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname); > +} > + > +static ssize_t arcxcnn_leden_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct arcxcnn *lp = dev_get_drvdata(dev); > + > + return scnprintf(buf, PAGE_SIZE, "%02X\n", lp->pdata->leden); > +} > + > +static ssize_t arcxcnn_leden_store(struct device *dev, > + struct device_attribute *attr, const char *buf, size_t len) > +{ > + struct arcxcnn *lp = dev_get_drvdata(dev); > + unsigned long leden; > + > + if (kstrtoul(buf, 0, &leden)) > + return 0; > + > + if (leden != lp->pdata->leden) { > + /* don't allow 0 for leden, use power to turn all off */ > + if (leden == 0) > + return -EINVAL; > + lp->pdata->leden = leden & ARCXCNN_LEDEN_MASK; > + arcxcnn_update_bit(lp, ARCXCNN_LEDEN, > + ARCXCNN_LEDEN_MASK, lp->pdata->leden); > + } > + > + return len; > +} > + > +static DEVICE_ATTR(chip_id, 0444, arcxcnn_chip_id_show, NULL); > +static DEVICE_ATTR(leden, 0664, arcxcnn_leden_show, arcxcnn_leden_store); > + > +static struct attribute *arcxcnn_attributes[] = { > + &dev_attr_chip_id.attr, > + &dev_attr_leden.attr, > + NULL, > +}; > + > +static const struct attribute_group arcxcnn_attr_group = { > + .attrs = arcxcnn_attributes, > +}; > + > +static void arcxcnn_parse_dt(struct arcxcnn *lp) > +{ > + struct device *dev = lp->dev; > + struct device_node *node = dev->of_node; > + u32 prog_val, num_entry, entry, sources[ARCXCNN_LEDEN_BITS]; > + int ret; > + > + /* device tree entry isn't required, defaults are OK */ > + if (!node) > + return; > + > + ret = of_property_read_string(node, "label", &lp->pdata->name); > + if (ret < 0) > + lp->pdata->name = NULL; > + > + ret = of_property_read_u32(node, "default-brightness", &prog_val); > + if (ret == 0) > + lp->pdata->initial_brightness = prog_val; > + > + ret = of_property_read_u32(node, "arcticsand,led-config-0", &prog_val); > + if (ret == 0) > + lp->pdata->led_config_0 = (u8)prog_val; > + > + ret = of_property_read_u32(node, "arcticsand,led-config-1", &prog_val); > + if (ret == 0) > + lp->pdata->led_config_1 = (u8)prog_val; > + > + ret = of_property_read_u32(node, "arcticsand,dim-freq", &prog_val); > + if (ret == 0) > + lp->pdata->dim_freq = (u8)prog_val; > + > + ret = of_property_read_u32(node, "arcticsand,comp-config", &prog_val); > + if (ret == 0) > + lp->pdata->comp_config = (u8)prog_val; > + > + ret = of_property_read_u32(node, "arcticsand,filter-config", &prog_val); > + if (ret == 0) > + lp->pdata->filter_config = (u8)prog_val; > + > + ret = of_property_read_u32(node, "arcticsand,trim-config", &prog_val); > + if (ret == 0) > + lp->pdata->trim_config = (u8)prog_val; > + > + ret = of_property_count_u32_elems(node, "led-sources"); > + if (ret < 0) { > + lp->pdata->leden = ARCXCNN_LEDEN_MASK; /* all on is default */ > + } else { > + num_entry = ret; > + if (num_entry > ARCXCNN_LEDEN_BITS) > + num_entry = ARCXCNN_LEDEN_BITS; > + > + ret = of_property_read_u32_array(node, "led-sources", sources, > + num_entry); > + if (ret < 0) { > + dev_err(dev, "led-sources node is invalid.\n"); > + return; > + } > + > + lp->pdata->leden = 0; > + > + /* for each enable in source, set bit in led enable */ > + for (entry = 0; entry < num_entry; entry++) { > + u8 onbit = 1 << sources[entry]; > + > + lp->pdata->leden |= onbit; > + } > + } > +} > + > +static int arcxcnn_probe(struct i2c_client *cl, const struct i2c_device_id > *id) > +{ > + struct arcxcnn *lp; > + int ret; > + u8 regval; > + u16 chipid; > + > + if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) > + return -EIO; > + > + lp = devm_kzalloc(&cl->dev, sizeof(*lp), GFP_KERNEL); > + if (!lp) > + return -ENOMEM; > + > + lp->client = cl; > + lp->dev = &cl->dev; > + lp->pdata = dev_get_platdata(&cl->dev); > + > + /* reset the device */ > + i2c_smbus_write_byte_data(lp->client, > + ARCXCNN_CMD, ARCXCNN_CMD_RESET); > + > + /* read device ID */ > + regval = i2c_smbus_read_byte_data(lp->client, ARCXCNN_ID_MSB); > + chipid = regval; > + chipid <<= 8; > + > + regval = i2c_smbus_read_byte_data(lp->client, ARCXCNN_ID_LSB); > + chipid |= regval; > + > + snprintf(lp->chipname, sizeof(lp->chipname), > + "%s-%04X", id->name, chipid); > + > + if (!lp->pdata) { > + lp->pdata = devm_kzalloc(lp->dev, > + sizeof(*lp->pdata), GFP_KERNEL); > + if (!lp->pdata) > + return -ENOMEM; > + > + /* Setup defaults based on power-on defaults */ > + lp->pdata->name = NULL; > + lp->pdata->initial_brightness = s_ibright; > + lp->pdata->leden = s_ileden; > + > + lp->pdata->led_config_0 = i2c_smbus_read_byte_data( > + lp->client, ARCXCNN_FADECTRL); > + > + lp->pdata->led_config_1 = i2c_smbus_read_byte_data( > + lp->client, ARCXCNN_ILED_CONFIG); > + /* insure dim mode is not default pwm */ > + lp->pdata->led_config_1 |= ARCXCNN_ILED_DIM_INT; > + > + lp->pdata->dim_freq = i2c_smbus_read_byte_data( > + lp->client, ARCXCNN_DIMFREQ); > + > + lp->pdata->comp_config = i2c_smbus_read_byte_data( > + lp->client, ARCXCNN_COMP_CONFIG); > + > + lp->pdata->filter_config = i2c_smbus_read_byte_data( > + lp->client, ARCXCNN_FILT_CONFIG); > + > + lp->pdata->trim_config = i2c_smbus_read_byte_data( > + lp->client, ARCXCNN_IMAXTUNE); > + > + if (IS_ENABLED(CONFIG_OF)) > + arcxcnn_parse_dt(lp); > + } > + > + i2c_set_clientdata(cl, lp); > + > + /* constrain settings to what is possible */ > + if (lp->pdata->initial_brightness > MAX_BRIGHTNESS) > + lp->pdata->initial_brightness = MAX_BRIGHTNESS; > + > + /* set initial brightness */ > + arcxcnn_set_brightness(lp, lp->pdata->initial_brightness); > + > + /* set other register values directly */ > + i2c_smbus_write_byte_data(lp->client, ARCXCNN_FADECTRL, > + lp->pdata->led_config_0); > + i2c_smbus_write_byte_data(lp->client, ARCXCNN_ILED_CONFIG, > + lp->pdata->led_config_1); > + i2c_smbus_write_byte_data(lp->client, ARCXCNN_DIMFREQ, > + lp->pdata->dim_freq); > + i2c_smbus_write_byte_data(lp->client, ARCXCNN_COMP_CONFIG, > + lp->pdata->comp_config); > + i2c_smbus_write_byte_data(lp->client, ARCXCNN_FILT_CONFIG, > + lp->pdata->filter_config); > + i2c_smbus_write_byte_data(lp->client, ARCXCNN_IMAXTUNE, > + lp->pdata->trim_config); > + > + /* set initial LED Enables */ > + arcxcnn_update_bit(lp, ARCXCNN_LEDEN, > + ARCXCNN_LEDEN_MASK, lp->pdata->leden); > + > + ret = arcxcnn_backlight_register(lp); > + if (ret) { > + dev_err(lp->dev, > + "failed to register backlight. err: %d\n", ret); > + return ret; > + } > + > + ret = sysfs_create_group(&lp->dev->kobj, &arcxcnn_attr_group); > + if (ret) { > + dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); > + return ret; > + } > + > + backlight_update_status(lp->bl); > + > + return 0; > +} > + > +static int arcxcnn_remove(struct i2c_client *cl) > +{ > + struct arcxcnn *lp = i2c_get_clientdata(cl); > + > + if (!s_no_reset_on_remove) { > + /* disable all strings */ > + i2c_smbus_write_byte_data(lp->client, > + ARCXCNN_LEDEN, 0x00); > + /* reset the device */ > + i2c_smbus_write_byte_data(lp->client, > + ARCXCNN_CMD, ARCXCNN_CMD_RESET); > + } > + lp->bl->props.brightness = 0; > + > + backlight_update_status(lp->bl); > + > + sysfs_remove_group(&lp->dev->kobj, &arcxcnn_attr_group); > + > + return 0; > +} > + > +static const struct of_device_id arcxcnn_dt_ids[] = { > + { .compatible = "arc,arc2c0608" }, > + { } > +}; > +MODULE_DEVICE_TABLE(of, arcxcnn_dt_ids); > + > +static const struct i2c_device_id arcxcnn_ids[] = { > + {"arc2c0608", ARC2C0608}, > + { } > +}; > +MODULE_DEVICE_TABLE(i2c, arcxcnn_ids); > + > +static struct i2c_driver arcxcnn_driver = { > + .driver = { > + .name = "arcxcnn_bl", > + .of_match_table = of_match_ptr(arcxcnn_dt_ids), > + }, > + .probe = arcxcnn_probe, > + .remove = arcxcnn_remove, > + .id_table = arcxcnn_ids, > +}; > +module_i2c_driver(arcxcnn_driver); > + > +MODULE_LICENSE("GPL v2"); > +MODULE_AUTHOR("Brian Dodge <bdo...@arcticsand.com>"); > +MODULE_DESCRIPTION("ARCXCNN Backlight driver"); > diff --git a/include/linux/i2c/arcxcnn.h b/include/linux/i2c/arcxcnn.h > new file mode 100644 > index 0000000..e378d63 > --- /dev/null > +++ b/include/linux/i2c/arcxcnn.h > @@ -0,0 +1,51 @@ > +/* > + * Backlight driver for ArcticSand ARC_X_C_0N_0N Devices > + * > + * Copyright 2016 ArcticSand, Inc. > + * Author : Brian Dodge <bdo...@arcticsand.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, see <http://www.gnu.org/licenses/>. > + */ > + > +#ifndef _ARCXCNN_H > +#define _ARCXCNN_H > + > +enum arcxcnn_chip_id { > + ARC2C0608 > +}; > + > +/** > + * struct arcxcnn_platform_data > + * @name : Backlight driver name (NULL will use default) > + * @initial_brightness : initial value of backlight brightness > + * @leden : initial LED string enables, upper bit is global on/off > + * @led_config_0 : fading speed (period between intensity steps) > + * @led_config_1 : misc settings, see datasheet > + * @dim_freq : pwm dimming frequency if in pwm mode > + * @comp_config : misc config, see datasheet > + * @filter_config : RC/PWM filter config, see datasheet > + * @trim_config : full scale current trim, see datasheet > + */ > +struct arcxcnn_platform_data { > + const char *name; > + u16 initial_brightness; > + u8 leden; > + u8 led_config_0; > + u8 led_config_1; > + u8 dim_freq; > + u8 comp_config; > + u8 filter_config; > + u8 trim_config; > +}; > + > +#endif -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog
