The pwm-fan driver is extended to support multiple fan tachometer
signals connected to GPIO inputs. This is intended to support the case
where a single PWM output signal is routed to multiple fans, each of
which have a tachometer output connected back to a GPIO pin.
The number of fan tachometer inputs is determined by the number of
interrupt sources configured for the pwm-fan device. The number of
pulses-per-revolution entries should match the number of interrupt
sources so that each input has a value assigned.
The fan tachometer measurements are exposed as sysfs files fan1_input,
fan2_input, etc up to the number of configured inputs.
Signed-off-by: Paul Barker <pbarker@xxxxxxxxxxxx>
---
drivers/hwmon/pwm-fan.c | 72 ++++++++++++++++++++++++-----------------
1 file changed, 43 insertions(+), 29 deletions(-)
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 7c75ce78b36a..03a3b57e2d99 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -36,7 +36,8 @@ struct pwm_fan_ctx {
struct pwm_device *pwm;
struct regulator *reg_en;
- struct pwm_fan_tach *tach;
+ int tach_count;
+ struct pwm_fan_tach *tachs;
ktime_t sample_start;
struct timer_list rpm_timer;
@@ -63,15 +64,19 @@ static irqreturn_t pulse_handler(int irq, void *dev_id)
static void sample_timer(struct timer_list *t)
{
struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer);
- struct pwm_fan_tach *tach = ctx->tach;
unsigned int delta = ktime_ms_delta(ktime_get(), ctx->sample_start);
- int pulses;
+ int i;
if (delta) {
- pulses = atomic_read(&tach->pulses);
- atomic_sub(pulses, &tach->pulses);
- tach->rpm = (unsigned int)(pulses * 1000 * 60) /
- (tach->pulses_per_revolution * delta);
+ for (i = 0; i < ctx->tach_count; i++) {
+ struct pwm_fan_tach *tach = &ctx->tachs[i];
+ int pulses;
+
+ pulses = atomic_read(&tach->pulses);
+ atomic_sub(pulses, &tach->pulses);
+ tach->rpm = (unsigned int)(pulses * 1000 * 60) /
+ (tach->pulses_per_revolution * delta);
+ }
ctx->sample_start = ktime_get();
}
@@ -143,7 +148,8 @@ static ssize_t rpm_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
- struct pwm_fan_tach *tach = ctx->tach;
+ struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
+ struct pwm_fan_tach *tach = &ctx->tachs[sensor_attr->index];
return sprintf(buf, "%u\n", tach->rpm);
}
@@ -267,8 +273,8 @@ static int pwm_fan_probe(struct platform_device *pdev)
struct device *hwmon;
int ret;
struct pwm_state state = { };
- int tach_count;
size_t sz;
+ int i;
ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
if (!ctx)
@@ -317,30 +323,32 @@ static int pwm_fan_probe(struct platform_device *pdev)
if (ret)
return ret;
- tach_count = platform_irq_count(pdev);
- if (tach_count < 0)
- return dev_err_probe(dev, tach_count,
+ ctx->tach_count = platform_irq_count(pdev);
+ if (ctx->tach_count < 0)
+ return dev_err_probe(dev, ctx->tach_count,
"Could not get number of fan tachometer inputs\n");
+ dev_dbg(dev, "%d fan tachometer inputs\n", ctx->tach_count);
- sz = (2 + tach_count) * sizeof(struct attribute *);
+ sz = (2 + ctx->tach_count) * sizeof(struct attribute *);
ctx->fan_group.attrs = devm_kzalloc(dev, sz, GFP_KERNEL);
if (!ctx->fan_group.attrs)
return -ENOMEM;
ctx->fan_group.attrs[0] = &sensor_dev_attr_pwm1.dev_attr.attr;
- if (tach_count > 0) {
- struct pwm_fan_tach *tach;
- u32 ppr = 2;
-
- ctx->tach = devm_kzalloc(dev, sizeof(struct pwm_fan_tach),
- GFP_KERNEL);
- if (!ctx->tach)
+ if (ctx->tach_count > 0) {
+ sz = ctx->tach_count * sizeof(struct pwm_fan_tach);
+ ctx->tachs = devm_kzalloc(dev, sz, GFP_KERNEL);
+ if (!ctx->tachs)
return -ENOMEM;
+ }
- tach = ctx->tach;
+ for (i = 0; i < ctx->tach_count; i++) {
+ struct pwm_fan_tach *tach = &ctx->tachs[i];
+ u32 ppr = 2;
+ char *name;
- tach->irq = platform_get_irq(pdev, 0);
+ tach->irq = platform_get_irq(pdev, i);
if (tach->irq == -EPROBE_DEFER)
return tach->irq;
if (tach->irq > 0) {
@@ -354,9 +362,10 @@ static int pwm_fan_probe(struct platform_device *pdev)
}
}
- of_property_read_u32(dev->of_node,
- "pulses-per-revolution",
- &ppr);
+ of_property_read_u32_index(dev->of_node,
+ "pulses-per-revolution",
+ i,
+ &ppr);
tach->pulses_per_revolution = ppr;
if (!tach->pulses_per_revolution) {
dev_err(dev, "pulses-per-revolution can't be zero.\n");
@@ -365,14 +374,19 @@ static int pwm_fan_probe(struct platform_device *pdev)
sysfs_attr_init(&tach->sensor_attr.dev_attr.attr);
- tach->sensor_attr.dev_attr.attr.name = "fan1_input";
+ name = devm_kzalloc(dev, 16, GFP_KERNEL);
+ snprintf(name, 16, "fan%d_input", i + 1);
+ tach->sensor_attr.dev_attr.attr.name = name;
tach->sensor_attr.dev_attr.attr.mode = 0444;
tach->sensor_attr.dev_attr.show = rpm_show;
- ctx->fan_group.attrs[1] = &tach->sensor_attr.dev_attr.attr;
+ tach->sensor_attr.index = i;
+ ctx->fan_group.attrs[i + 1] = &tach->sensor_attr.dev_attr.attr;
- dev_dbg(dev, "tach: irq=%d, pulses_per_revolution=%d\n",
- tach->irq, tach->pulses_per_revolution);
+ dev_dbg(dev, "%s: irq=%d, pulses_per_revolution=%d\n",
+ name, tach->irq, tach->pulses_per_revolution);
+ }
+ if (ctx->tach_count > 0) {
ctx->sample_start = ktime_get();
mod_timer(&ctx->rpm_timer, jiffies + HZ);
}
--
2.29.2
