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From:   =?UTF-8?q?V=C3=A1clav=20Kubern=C3=A1t?= <kubernat@cesnet.cz>
To:     Jean Delvare <jdelvare@suse.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Jonathan Corbet <corbet@lwn.net>, linux-hwmon@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     =?UTF-8?q?V=C3=A1clav=20Kubern=C3=A1t?= <kubernat@cesnet.cz>
Subject: [PATCH v5 4/5] hwmon: (max31790) Allow setting fan*_div
Date:   Wed, 12 May 2021 03:30:50 +0200
Message-Id: <20210512013052.903297-4-kubernat@cesnet.cz>
In-Reply-To: <20210512013052.903297-1-kubernat@cesnet.cz>
References: <20210512013052.903297-1-kubernat@cesnet.cz>
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Precedence: bulk

Right now, the divisor (which determines the speed range) is only set
when in RPM mode. However, the speed range also affects the input RPM,
which means, to get more accurate readings, this speed range needs to be
set.

Signed-off-by: Václav Kubernát <kubernat@cesnet.cz>
---
 Documentation/hwmon/max31790.rst |  1 +
 drivers/hwmon/max31790.c         | 66 ++++++++++++++++++++++++++------
 2 files changed, 55 insertions(+), 12 deletions(-)

diff --git a/Documentation/hwmon/max31790.rst b/Documentation/hwmon/max31790.rst
index d2ac4e926905..35afa5f0395a 100644
--- a/Documentation/hwmon/max31790.rst
+++ b/Documentation/hwmon/max31790.rst
@@ -38,6 +38,7 @@ Sysfs entries
 fan[1-12]_enable   RW  enable fan speed monitoring
 fan[1-12]_input    RO  fan tachometer speed in RPM
 fan[1-12]_fault    RO  fan experienced fault
+fan[1-12]_div      RW  set the measurable speed range, not available in RPM mode
 fan[1-6]_target    RW  desired fan speed in RPM
 pwm[1-6]_enable    RW  regulator mode, 0=no control, sets 0% PWM,
 				       1=manual (pwm) mode,
diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c
index 6e0ffbcf0d28..8b04f4c01752 100644
--- a/drivers/hwmon/max31790.c
+++ b/drivers/hwmon/max31790.c
@@ -156,6 +156,26 @@ static int write_reg_word(struct regmap *regmap, u8 reg, u16 val)
 	return regmap_bulk_write(regmap, reg, bulk_val, 2);
 }
 
+static int bits_for_speed_range(long speed_range)
+{
+	switch (speed_range) {
+	case 1:
+		return 0x0;
+	case 2:
+		return 0x1;
+	case 4:
+		return 0x2;
+	case 8:
+		return 0x3;
+	case 16:
+		return 0x4;
+	case 32:
+		return 0x5;
+	default:
+		return -1;
+	}
+}
+
 static int max31790_read_fan(struct device *dev, u32 attr, int channel,
 			     long *val)
 {
@@ -203,6 +223,9 @@ static int max31790_read_fan(struct device *dev, u32 attr, int channel,
 	case hwmon_fan_enable:
 		*val = !!(data->fan_config[channel] & MAX31790_FAN_CFG_TACH_INPUT_EN);
 		return 0;
+	case hwmon_fan_div:
+		*val = get_tach_period(data->fan_config[channel]);
+		return 0;
 	default:
 		return -EOPNOTSUPP;
 	}
@@ -254,6 +277,24 @@ static int max31790_write_fan(struct device *dev, u32 attr, int channel,
 				   MAX31790_REG_FAN_CONFIG(channel),
 				   data->fan_config[channel]);
 		break;
+	case hwmon_fan_div:
+		if (data->fan_config[channel] & MAX31790_FAN_CFG_RPM_MODE) {
+			err = -EINVAL;
+			break;
+		}
+		sr = bits_for_speed_range(val);
+		if (sr < 0) {
+			err = -EINVAL;
+			break;
+		}
+
+		data->fan_dynamics[channel] = ((data->fan_dynamics[channel] &
+						~MAX31790_FAN_DYN_SR_MASK) |
+					       (sr << MAX31790_FAN_DYN_SR_SHIFT));
+		err = regmap_write(regmap,
+				   MAX31790_REG_FAN_DYNAMICS(channel),
+				   data->fan_dynamics[channel]);
+		break;
 	default:
 		err = -EOPNOTSUPP;
 		break;
@@ -282,6 +323,7 @@ static umode_t max31790_fan_is_visible(const void *_data, u32 attr, int channel)
 			return 0644;
 		return 0;
 	case hwmon_fan_enable:
+	case hwmon_fan_div:
 		if (channel < NR_CHANNEL ||
 		    (fan_config & MAX31790_FAN_CFG_TACH_INPUT))
 			return 0644;
@@ -432,18 +474,18 @@ static umode_t max31790_is_visible(const void *data,
 
 static const struct hwmon_channel_info *max31790_info[] = {
 	HWMON_CHANNEL_INFO(fan,
-			   HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
-			   HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
-			   HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
-			   HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
-			   HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
-			   HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
-			   HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
-			   HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
-			   HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
-			   HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
-			   HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
-			   HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT),
+			   HWMON_F_DIV | HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
+			   HWMON_F_DIV | HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
+			   HWMON_F_DIV | HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
+			   HWMON_F_DIV | HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
+			   HWMON_F_DIV | HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
+			   HWMON_F_DIV | HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,
+			   HWMON_F_DIV | HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
+			   HWMON_F_DIV | HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
+			   HWMON_F_DIV | HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
+			   HWMON_F_DIV | HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
+			   HWMON_F_DIV | HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
+			   HWMON_F_DIV | HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT),
 	HWMON_CHANNEL_INFO(pwm,
 			   HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
 			   HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
-- 
2.31.1