From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lf1-f49.google.com (mail-lf1-f49.google.com [209.85.167.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BC7F338DC53 for ; Mon, 24 Aug 2026 20:14:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.49 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787602458; cv=none; b=Vw2h7TuKsXeHlS9zUQ5YfR3nT3tp2muhHIlLzQDSIS4azbTjeM+LUw9VkfCs/RbQh4NjAhHpig08UmlAjSGG0odLeNejwhr9ecI8uZb0kJe413QVw68+DD8KyNg8l/vpMNiOojd64iv4KlmIaeiR5LJ7r5hrIRVb8iw0TIc5AB4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787602458; c=relaxed/simple; bh=Z8Q6Cje1VKDpJnaujnQksPmxZ0zKmJ2ZAE7GDaSwEZM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=A6Gw9nvSrFevkjlLxVBFhaSpJFCdyqy+UsN7SZ/hTfnm/W9Pn+IOfNE5e9ZiiX6GCglQCCK7hWu9O5UGopbed5c8q5DSgy3KbwWMuaajnGtjK5IMoLwSu96DHj02jM/DWTaCkoXDlc9tOaqlng6y271isCoYwPB+2EG1K1Rta9g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=S3zlh/r/; arc=none smtp.client-ip=209.85.167.49 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="S3zlh/r/" Received: by mail-lf1-f49.google.com with SMTP id 2adb3069b0e04-5aeba09900bso3104036e87.2 for ; Mon, 24 Aug 2026 13:14:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1787602455; x=1788207255; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=nQXWTdBiGOmg9WRHvHkejupB58j8w1lmLGZTr2gy6Vs=; b=S3zlh/r/sltgB85ewkIuFuOeyCGVIgROqCL0SNLvrJtUzSZhHv3dt/65psU5F70ceF dLUfEez3qOggbkWr+u/HAF4Cjw+38FRKIqa/DMPX7JwYJs2sDW/LVQCfzvXeAQ92iTKe uy+3SBqe0EzDTFLHVgbRy+63xQdT39WkzDnjFCKFv4uL8YcRh3RNUh4uqo2vmVtXataY 1GU53X5ComV3MU1LUxMM0Plpt88w+86FlNl+MlJKjkzsim2iIrlFi8C/YSCm0ik1KBak qdj3XwYFH6SzgD6X/YJVgIMGoTrcydb+xztfhL9VMvYdYmSdOtlHL5bzHJ/eFw1VYhQB 9Cyw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787602455; x=1788207255; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=nQXWTdBiGOmg9WRHvHkejupB58j8w1lmLGZTr2gy6Vs=; b=MnPxaOABITUn/4LV3xcI9Aa3eRIWFyf6NpRSSyNxwgzOfKKCMOhjYY1lDwW4hTnAZR ie7TjUlKlgqoAtC9dGRW6Aa6MbTdGYvsmgrx6VZSqPlDY03SZ+Ppv/L9fzLBltDRgnwh WTWOHZeYmp1pk+/gMokqQrRWNy3ZlRS+bNcx2lLBXHmuCuFxsmH53J0vb/NT7wKwDDRf Vs+aUjKYEH38Cw/TwfAw8UN/JqOqDEFpDSoxD/tZ9ta5eX/Wu8tMVdNa3Ty5qw2WuDsw vBKiFS8yry5ZOUdO4O7umXs3nBBqAI/B6I4TBlJ653q32yAvZYMSLsDqEJAcMKpNAjbI VIkQ== X-Forwarded-Encrypted: i=1; AHgh+RpZ4fD2VFZ+MhspwBiaEWrWu9IRyQVFc+SCOlH8eqbWX2Z+bqcaEJvu6cjYBnfggsnMfzqitB+zntYl5jI=@vger.kernel.org X-Gm-Message-State: AFuF++mxnqM4oU4qRdAPZloWO1zmalnNZudO22IGujviklPIyNO5+SpY g1TS7f9OHdJ5fjqOidTRdjme5soytbsZxvbM7SZwdjpuuiJvy7OEsckF X-Gm-Gg: AR+sD10W6DpuSuejJbSSHPqlXX34ZZeXg7EfXM+gmnTs28Wx481F8jlDFS9zfMcCk7n /bvl+bp79uQB2qUZGhaofs5Vn3bHoJcBgvZyAdzQsTmviP5GgGvBYAYsBs2a01tP2K6+epKaRqL 84OUc1zatDvEeof2Kusca4nyIDUCvK25oEAyKSrUw73BnEBul8qJ8ea1iOUj8C2BfppG3aXD7bI 9NZjSb8ZRKlitKWOQ77THgjjWQoeBU6WAZNmCDZ2T3ffYC6gK/eXPD8rr9cJOmzKuuHtTLVAKsP yBnz+cvcxzgq1FjRRiBvDfcJ+I0ljjxJfibSZcBWEPdUymeI5IlmfTqHeuKR5De6OJAt6/NEQnk gYgW6Qt7A+XMF0x3IQNaRhsOYQtMoV7NkO+HBKce9+pAzX56bv79J5ZAvFsR9xRzXGHVgu/dahg pNZFgOH3b5YvcEBXFuHdTMFAg/TX8+ILeIacyVuVjA2MhBOhSVXymF5c8nFX4QslYY6sqEhH0TB J9SF0Kz1ThJR7MHJxKdnsLeyNFan8t0s9H5x14Tfy1YXmrW1EZpC8Hho2lzaa2TKGBUs1AdoTE= X-Received: by 2002:a05:6512:3f25:b0:5ae:b969:417d with SMTP id 2adb3069b0e04-5b49cc05204mr327990e87.0.1787602454609; Mon, 24 Aug 2026 13:14:14 -0700 (PDT) Received: from yantra.. (dsl-trebng21-58c187-236.dhcp.inet.fi. [88.193.135.236]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5b48ce0cd9csm1923620e87.71.2026.08.24.13.14.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Aug 2026 13:14:14 -0700 (PDT) From: Rupesh Majhi To: Andy Shevchenko , Bill Wendling , David Lechner , Eddie James , Joel Stanley , Jonathan Cameron , Justin Stitt , Nathan Chancellor , Nick Desaulniers , =?UTF-8?q?Nuno=20S=C3=A1?= Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Rupesh Majhi Subject: [PATCH v6 3/6] iio: pressure: dps310: rework the raw read paths Date: Mon, 24 Aug 2026 23:12:00 +0300 Message-ID: <20260824201203.396651-4-zoone.rupert@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260824201203.396651-1-zoone.rupert@gmail.com> References: <20260824201203.396651-1-zoone.rupert@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Raw reads take the lock themselves, so a processed pressure read takes it twice: once for the raw read, then again when dps310_calculate_pressure() trylocks to refresh temperature. Refresh is skipped whenever lock is busy. Split raw reads into variants that expect lock held, one helper per channel taking it once for the whole sequence. Temperature refresh is unconditional now. Buffered capture later in this series needs the same shape. Also use get_unaligned_be24() for 24-bit results, and mark functions that need the lock with __must_hold() rather than a comment. Assisted-by: Claude:claude-opus-5 Signed-off-by: Rupesh Majhi --- drivers/iio/pressure/dps310.c | 159 +++++++++++++++++++--------------- 1 file changed, 87 insertions(+), 72 deletions(-) diff --git a/drivers/iio/pressure/dps310.c b/drivers/iio/pressure/dps310.c index 25d1c79876e6..269a71ea3e7a 100644 --- a/drivers/iio/pressure/dps310.c +++ b/drivers/iio/pressure/dps310.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include @@ -286,8 +287,8 @@ static int dps310_get_temp_precision(struct dps310_data *data, int *val) return 0; } -/* Called with lock held */ static int dps310_set_pres_precision(struct dps310_data *data, int val) + __must_hold(&data->lock) { int rc; u8 shift_en; @@ -305,8 +306,8 @@ static int dps310_set_pres_precision(struct dps310_data *data, int val) DPS310_PRS_PRC_BITS, ilog2(val)); } -/* Called with lock held */ static int dps310_set_temp_precision(struct dps310_data *data, int val) + __must_hold(&data->lock) { int rc; u8 shift_en; @@ -324,8 +325,8 @@ static int dps310_set_temp_precision(struct dps310_data *data, int val) DPS310_TMP_PRC_BITS, ilog2(val)); } -/* Called with lock held */ static int dps310_set_pres_samp_freq(struct dps310_data *data, int freq) + __must_hold(&data->lock) { u8 val; @@ -338,8 +339,8 @@ static int dps310_set_pres_samp_freq(struct dps310_data *data, int freq) DPS310_PRS_RATE_BITS, val); } -/* Called with lock held */ static int dps310_set_temp_samp_freq(struct dps310_data *data, int freq) + __must_hold(&data->lock) { u8 val; @@ -438,6 +439,7 @@ static int dps310_ready_status(struct dps310_data *data, int ready_bit, int time } static int dps310_ready(struct dps310_data *data, int ready_bit, int timeout) + __must_hold(&data->lock) { int rc; @@ -463,82 +465,87 @@ static int dps310_ready(struct dps310_data *data, int ready_bit, int timeout) return 0; } -static int dps310_read_pres_raw(struct dps310_data *data) +static int dps310_read_pres_raw_locked(struct dps310_data *data) + __must_hold(&data->lock) { int rc; int rate; int timeout; - s32 raw; u8 val[3]; - if (mutex_lock_interruptible(&data->lock)) - return -EINTR; - rc = dps310_get_pres_samp_freq(data, &rate); if (rc) - goto done; + return rc; timeout = DPS310_POLL_TIMEOUT_US(rate); /* Poll for sensor readiness; base the timeout upon the sample rate. */ rc = dps310_ready(data, DPS310_PRS_RDY, timeout); if (rc) - goto done; + return rc; rc = regmap_bulk_read(data->regmap, DPS310_PRS_BASE, val, sizeof(val)); if (rc < 0) - goto done; + return rc; - raw = (val[0] << 16) | (val[1] << 8) | val[2]; - data->pressure_raw = sign_extend32(raw, 23); + data->pressure_raw = sign_extend32(get_unaligned_be24(val), 23); -done: - mutex_unlock(&data->lock); - return rc; + return 0; } -/* Called with lock held */ static int dps310_read_temp_ready(struct dps310_data *data) + __must_hold(&data->lock) { int rc; u8 val[3]; - s32 raw; rc = regmap_bulk_read(data->regmap, DPS310_TMP_BASE, val, sizeof(val)); if (rc < 0) return rc; - raw = (val[0] << 16) | (val[1] << 8) | val[2]; - data->temp_raw = sign_extend32(raw, 23); + data->temp_raw = sign_extend32(get_unaligned_be24(val), 23); return 0; } -static int dps310_read_temp_raw(struct dps310_data *data) +static int dps310_read_temp_raw_locked(struct dps310_data *data) + __must_hold(&data->lock) { int rc; int rate; int timeout; - if (mutex_lock_interruptible(&data->lock)) - return -EINTR; - rc = dps310_get_temp_samp_freq(data, &rate); if (rc) - goto done; + return rc; timeout = DPS310_POLL_TIMEOUT_US(rate); /* Poll for sensor readiness; base the timeout upon the sample rate. */ rc = dps310_ready(data, DPS310_TMP_RDY, timeout); if (rc) - goto done; + return rc; + + return dps310_read_temp_ready(data); +} + +/* + * Refresh the cached temperature if a new measurement is ready, so that the + * pressure compensation uses a recent value. An error is not fatal here, the + * previous temperature is used instead. + */ +static void dps310_refresh_temp_locked(struct dps310_data *data) + __must_hold(&data->lock) +{ + int rc; + int t_ready; - rc = dps310_read_temp_ready(data); + rc = regmap_read(data->regmap, DPS310_MEAS_CFG, &t_ready); + if (rc) + return; -done: - mutex_unlock(&data->lock); - return rc; + if (t_ready & DPS310_TMP_RDY) + dps310_read_temp_ready(data); } static bool dps310_is_writeable_reg(struct device *dev, unsigned int reg) @@ -580,59 +587,47 @@ static int dps310_write_raw(struct iio_dev *iio, struct iio_chan_spec const *chan, int val, int val2, long mask) { - int rc; struct dps310_data *data = iio_priv(iio); - if (mutex_lock_interruptible(&data->lock)) + ACQUIRE(mutex_intr, lock)(&data->lock); + if (ACQUIRE_ERR(mutex_intr, &lock)) return -EINTR; switch (mask) { case IIO_CHAN_INFO_SAMP_FREQ: switch (chan->type) { case IIO_PRESSURE: - rc = dps310_set_pres_samp_freq(data, val); - break; + return dps310_set_pres_samp_freq(data, val); case IIO_TEMP: - rc = dps310_set_temp_samp_freq(data, val); - break; + return dps310_set_temp_samp_freq(data, val); default: - rc = -EINVAL; - break; + return -EINVAL; } - break; case IIO_CHAN_INFO_OVERSAMPLING_RATIO: switch (chan->type) { case IIO_PRESSURE: - rc = dps310_set_pres_precision(data, val); - break; + return dps310_set_pres_precision(data, val); case IIO_TEMP: - rc = dps310_set_temp_precision(data, val); - break; + return dps310_set_temp_precision(data, val); default: - rc = -EINVAL; - break; + return -EINVAL; } - break; default: - rc = -EINVAL; - break; + return -EINVAL; } - - mutex_unlock(&data->lock); - return rc; } static int dps310_calculate_pressure(struct dps310_data *data, int *val) + __must_hold(&data->lock) { int i; int rc; - int t_ready; int kpi; int kti; s64 rem = 0ULL; @@ -656,15 +651,6 @@ static int dps310_calculate_pressure(struct dps310_data *data, int *val) kp = (s64)kpi; kt = (s64)kti; - /* Refresh temp if it's ready, otherwise just use the latest value */ - if (mutex_trylock(&data->lock)) { - rc = regmap_read(data->regmap, DPS310_MEAS_CFG, &t_ready); - if (rc >= 0 && t_ready & DPS310_TMP_RDY) - dps310_read_temp_ready(data); - - mutex_unlock(&data->lock); - } - p = (s64)data->pressure_raw; t = (s64)data->temp_raw; @@ -710,6 +696,27 @@ static int dps310_calculate_pressure(struct dps310_data *data, int *val) return 0; } +/* + * Sample the pressure and compensate it, taking the lock once for the whole + * sequence rather than once per register read. + */ +static int dps310_read_pressure_value(struct dps310_data *data, int *val) +{ + int rc; + + ACQUIRE(mutex_intr, lock)(&data->lock); + if (ACQUIRE_ERR(mutex_intr, &lock)) + return -EINTR; + + rc = dps310_read_pres_raw_locked(data); + if (rc) + return rc; + + dps310_refresh_temp_locked(data); + + return dps310_calculate_pressure(data, val); +} + static int dps310_read_pressure(struct dps310_data *data, int *val, int *val2, long mask) { @@ -724,11 +731,7 @@ static int dps310_read_pressure(struct dps310_data *data, int *val, int *val2, return IIO_VAL_INT; case IIO_CHAN_INFO_PROCESSED: - rc = dps310_read_pres_raw(data); - if (rc) - return rc; - - rc = dps310_calculate_pressure(data, val); + rc = dps310_read_pressure_value(data, val); if (rc) return rc; @@ -747,6 +750,7 @@ static int dps310_read_pressure(struct dps310_data *data, int *val, int *val2, } static int dps310_calculate_temp(struct dps310_data *data, int *val) + __must_hold(&data->lock) { s64 c0; s64 t; @@ -768,6 +772,21 @@ static int dps310_calculate_temp(struct dps310_data *data, int *val) return 0; } +static int dps310_read_temp_value(struct dps310_data *data, int *val) +{ + int rc; + + ACQUIRE(mutex_intr, lock)(&data->lock); + if (ACQUIRE_ERR(mutex_intr, &lock)) + return -EINTR; + + rc = dps310_read_temp_raw_locked(data); + if (rc) + return rc; + + return dps310_calculate_temp(data, val); +} + static int dps310_read_temp(struct dps310_data *data, int *val, int *val2, long mask) { @@ -782,11 +801,7 @@ static int dps310_read_temp(struct dps310_data *data, int *val, int *val2, return IIO_VAL_INT; case IIO_CHAN_INFO_PROCESSED: - rc = dps310_read_temp_raw(data); - if (rc) - return rc; - - rc = dps310_calculate_temp(data, val); + rc = dps310_read_temp_value(data, val); if (rc) return rc; -- 2.43.0