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[78.94.0.50]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43d82dede2csm10331495e9.5.2025.03.26.11.29.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Mar 2025 11:29:41 -0700 (PDT) From: Your Name X-Google-Original-From: Your Name To: Jean Delvare , Guenter Roeck , linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Naresh Solanki Subject: [PATCH v2] hwmon: (max6639) : Allow setting target RPM Date: Wed, 26 Mar 2025 23:59:37 +0530 Message-ID: <20250326182937.513062-1-you@example.com> X-Mailer: git-send-email 2.42.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Naresh Solanki Currently, during startup, the fan is set to its maximum RPM by default, which may not be suitable for all use cases. This patch introduces support for specifying a target RPM via the Device Tree property "target-rpm". Changes: - Added `target_rpm` field to `max6639_data` structure to store the target RPM for each fan channel. - Modified `max6639_probe_child_from_dt()` to read the `"target-rpm"` property from the Device Tree and set `target_rpm` accordingly. - Updated `max6639_init_client()` to use `target_rpm` to compute the initial PWM duty cycle instead of defaulting to full speed (120/120). Behavior: - If `"target-rpm"` is specified, the fan speed is set accordingly. - If `"target-rpm"` is not specified, the previous behavior (full speed at startup) is retained. This allows better control over fan speed during system initialization. Signed-off-by: Naresh Solanki --- Changes in v2: - Pre-init target_rpm[] to 4000 RPM - Validate if target_rpm[] is within configured range. --- drivers/hwmon/max6639.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/hwmon/max6639.c b/drivers/hwmon/max6639.c index 32b4d54b2076..a06346496e1d 100644 --- a/drivers/hwmon/max6639.c +++ b/drivers/hwmon/max6639.c @@ -80,6 +80,7 @@ struct max6639_data { /* Register values initialized only once */ u8 ppr[MAX6639_NUM_CHANNELS]; /* Pulses per rotation 0..3 for 1..4 ppr */ u8 rpm_range[MAX6639_NUM_CHANNELS]; /* Index in above rpm_ranges table */ + u32 target_rpm[MAX6639_NUM_CHANNELS]; =20 /* Optional regulator for FAN supply */ struct regulator *reg; @@ -563,6 +564,10 @@ static int max6639_probe_child_from_dt(struct i2c_clie= nt *client, if (!err) data->rpm_range[i] =3D rpm_range_to_reg(val); =20 + err =3D of_property_read_u32(child, "target-rpm", &val); + if (!err) + data->target_rpm[i] =3D val; + return 0; } =20 @@ -573,6 +578,7 @@ static int max6639_init_client(struct i2c_client *clien= t, const struct device_node *np =3D dev->of_node; struct device_node *child; int i, err; + u8 target_duty; =20 /* Reset chip to default values, see below for GCONFIG setup */ err =3D regmap_write(data->regmap, MAX6639_REG_GCONFIG, MAX6639_GCONFIG_P= OR); @@ -586,6 +592,8 @@ static int max6639_init_client(struct i2c_client *clien= t, /* default: 4000 RPM */ data->rpm_range[0] =3D 1; data->rpm_range[1] =3D 1; + data->target_rpm[0] =3D 4000; + data->target_rpm[1] =3D 4000; =20 for_each_child_of_node(np, child) { if (strcmp(child->name, "fan")) @@ -639,8 +647,12 @@ static int max6639_init_client(struct i2c_client *clie= nt, if (err) return err; =20 - /* PWM 120/120 (i.e. 100%) */ - err =3D regmap_write(data->regmap, MAX6639_REG_TARGTDUTY(i), 120); + /* Set PWM based on target RPM if specified */ + if (data->target_rpm[i] > rpm_ranges[data->rpm_range[i]]) + data->target_rpm[i] =3D rpm_ranges[data->rpm_range[i]]; + + target_duty =3D 120 * data->target_rpm[i] / rpm_ranges[data->rpm_range[i= ]]; + err =3D regmap_write(data->regmap, MAX6639_REG_TARGTDUTY(i), target_duty= ); if (err) return err; } base-commit: 2115cbeec8a3ccc69e3b7ecdf97b4472b0829cfc --=20 2.42.0