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 | 91 ++++++++++++++++++++++++-----------------
1 file changed, 53 insertions(+), 38 deletions(-)
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 4a7f0e87b08f..cc64bae0ffa8 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -33,7 +33,8 @@ 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;
@@ -44,6 +45,7 @@ struct pwm_fan_ctx {
struct thermal_cooling_device *cdev;
struct hwmon_chip_info info;
+ struct hwmon_channel_info fan_channel;
};
static const u32 pwm_fan_channel_config_pwm[] = {
@@ -56,16 +58,6 @@ static const struct hwmon_channel_info pwm_fan_channel_pwm = {
.config = pwm_fan_channel_config_pwm,
};
-static const u32 pwm_fan_channel_config_fan[] = {
- HWMON_F_INPUT,
- 0
-};
-
-static const struct hwmon_channel_info pwm_fan_channel_fan = {
- .type = hwmon_fan,
- .config = pwm_fan_channel_config_fan,
-};
-
/* This handler assumes self resetting edge triggered interrupt. */
static irqreturn_t pulse_handler(int irq, void *dev_id)
{
@@ -79,15 +71,19 @@ 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();
}
@@ -157,7 +153,7 @@ static int pwm_fan_read(struct device *dev, enum hwmon_sensor_types type,
return 0;
case hwmon_fan:
- *val = ctx->tach->rpm;
+ *val = ctx->tachs[channel].rpm;
return 0;
default:
@@ -304,8 +300,10 @@ static int pwm_fan_probe(struct platform_device *pdev)
struct device *hwmon;
int ret;
struct pwm_state state = { };
- int tach_count;
const struct hwmon_channel_info **channels;
+ u32 *fan_channel_config;
+ int channel_count = 1; /* We always have a PWM channel. */
+ int i;
ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
if (!ctx)
@@ -354,29 +352,41 @@ 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);
- channels = devm_kcalloc(dev, tach_count + 2,
+ if (ctx->tach_count) {
+ channel_count++; /* We also have a FAN channel. */
+
+ ctx->tachs = devm_kcalloc(dev, ctx->tach_count,
+ sizeof(struct pwm_fan_tach),
+ GFP_KERNEL);
+ if (!ctx->tachs)
+ return -ENOMEM;
+
+ ctx->fan_channel.type = hwmon_fan;
+ fan_channel_config = devm_kcalloc(dev, ctx->tach_count + 1,
+ sizeof(u32), GFP_KERNEL);
+ if (!fan_channel_config)
+ return -ENOMEM;
+ ctx->fan_channel.config = fan_channel_config;
+ }
+
+ channels = devm_kcalloc(dev, channel_count + 1,
sizeof(struct hwmon_channel_info *), GFP_KERNEL);
if (!channels)
return -ENOMEM;
channels[0] = &pwm_fan_channel_pwm;
- if (tach_count > 0) {
- struct pwm_fan_tach *tach;
+ for (i = 0; i < ctx->tach_count; i++) {
+ struct pwm_fan_tach *tach = &ctx->tachs[i];
u32 ppr = 2;
- tach = devm_kzalloc(dev, sizeof(struct pwm_fan_tach),
- GFP_KERNEL);
- if (!tach)
- return -ENOMEM;
- ctx->tach = tach;
-
- 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) {
@@ -390,22 +400,27 @@ 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");
return -EINVAL;
}
- dev_dbg(dev, "tach: irq=%d, pulses_per_revolution=%d\n",
- tach->irq, tach->pulses_per_revolution);
+ fan_channel_config[i] = HWMON_F_INPUT;
+
+ dev_dbg(dev, "tach%d: irq=%d, pulses_per_revolution=%d\n",
+ i, tach->irq, tach->pulses_per_revolution);
+ }
+ if (ctx->tach_count > 0) {
ctx->sample_start = ktime_get();
mod_timer(&ctx->rpm_timer, jiffies + HZ);
- channels[1] = &pwm_fan_channel_fan;
+ channels[1] = &ctx->fan_channel;
}
ctx->info.ops = &pwm_fan_hwmon_ops;
--
2.26.2
