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mfd: MAX96745: add support line fault monitor status report

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GMSL2 serializers include a novel line-fault detection circuit that
detects and reports open-circuit, short-to-battery, short-to-ground,
and line-to-line short. The line-fault monitor is disabled by default,
and configuration options are available through registers. Its status
can be read by register.

Signed-off-by: Guochun Huang <hero.huang@rock-chips.com>
Change-Id: Ie548d25a8492f0ff883cc777c3a14049d25dda9a
This commit is contained in:
Guochun Huang 2022-08-12 14:12:55 +08:00 • committed by Tao Huang
commit 9218ea9567
2 changed files with 95 additions and 0 deletions
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81
drivers/mfd/max96745.c
View file

@ -119,6 +119,83 @@ static void max96745_power_on(struct max96745 *max96745)
FIELD_PREP(DIS_REM_CC, 1));
}
static ssize_t line_fault_monitor_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct max96745 *max96745 = dev_get_drvdata(device);
u32 pu_lf, lf, status;
regmap_read(max96745->regmap, 0x0005, &pu_lf);
/*
* Line-fault status of wire connected to LMN0/1/2/3 pin
*
* 0b000: Short to battery
* 0b001: Short to GND
* 0b010: Normal operation
* 0b011: Line open
* 0b1XX: Line-to-line short
*/
regmap_read(max96745->regmap, 0x0026, &lf);
if (FIELD_GET(PU_LF0, pu_lf)) {
status = (lf & LF_0);
return sprintf(buf, "%d\n", status);
}
if (FIELD_GET(PU_LF1, pu_lf)) {
status = (lf & LF_1) >> 4;
return sprintf(buf, "%d\n", status);
}
regmap_read(max96745->regmap, 0x0027, &lf);
if (FIELD_GET(PU_LF2, pu_lf)) {
status = (lf & LF_2);
return sprintf(buf, "%d\n", status);
}
if (FIELD_GET(PU_LF3, pu_lf)) {
status = (lf & LF_3) >> 4;
return sprintf(buf, "%d\n", status);
}
return sprintf(buf, "%d\n", -EINVAL);
}
static DEVICE_ATTR_RO(line_fault_monitor);
static struct attribute *max96745_attrs[] = {
&dev_attr_line_fault_monitor.attr,
NULL
};
static const struct attribute_group max96745_attr_group = {
.attrs = max96745_attrs,
};
static int max96745_sysfs_add(struct max96745 *max96745)
{
struct device *dev = max96745->dev;
int ret;
u32 ch;
ret = of_property_read_u32(dev->of_node, "line-fault-monitor", &ch);
if (!ret)
regmap_update_bits(max96745->regmap, 0x0005,
PU_LF0 << ch, PU_LF0 << ch);
ret = devm_device_add_group(dev, &max96745_attr_group);
if (ret) {
dev_err(dev, "failed to register sysfs. err: %d\n", ret);
return ret;
};
return 0;
}
static int max96745_i2c_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
@ -185,6 +262,10 @@ static int max96745_i2c_probe(struct i2c_client *client)
}
}
ret = max96745_sysfs_add(max96745);
if (ret)
return dev_err_probe(dev, ret, "failed to registers sysfs\n");
return 0;
}

14
include/linux/mfd/max96745.h
View file

@ -15,6 +15,12 @@
#define GPIO_C_REG(gpio) (0x0202 + ((gpio) * 8))
#define GPIO_D_REG(gpio) (0x0203 + ((gpio) * 8))
/* 0005h */
#define PU_LF3 BIT(3)
#define PU_LF2 BIT(2)
#define PU_LF1 BIT(1)
#define PU_LF0 BIT(0)
/* 0010h */
#define RESET_ALL BIT(7)
#define SLEEP BIT(3)
@ -23,6 +29,14 @@
#define LOCKED BIT(3)
#define ERROR BIT(2)
/* 0026h */
#define LF_0 GENMASK(2, 0)
#define LF_1 GENMASK(6, 4)
/* 0027h */
#define LF_2 GENMASK(2, 0)
#define LF_3 GENMASK(6, 4)
/* 0028h, 0032h */
#define LINK_EN BIT(7)