From patchwork Mon Oct 21 12:54:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matteo Martelli X-Patchwork-Id: 13844106 Received: from mail-wm1-f44.google.com (mail-wm1-f44.google.com [209.85.128.44]) (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 CECE31F7074; Mon, 21 Oct 2024 12:56:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.44 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729515392; cv=none; b=LXz6pSOL4mOn4HOf5g6AZTU70EV1hacjsJPyoeXqfcrY1UxaZ8nWW+NsRgnS677OlrxeFt0weVKdnzokEmUpiZy8UTmuPTAq/N4Ox6tT/KBhK/zWltZGs9dEL8eyz9F+OwLW9kswqt1W3IzFY+Pe0yLBGLO1Y0qeV3ek3JTkqfI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729515392; c=relaxed/simple; bh=QdYDXg+F9crN+GcA1VSjP47ejtoSADQbLgM8+WYO3yU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=eeMNP4dZvL0JgwqJaXTsNNKC+kxmgcLy7ZocBHf0hrzHUwovepWrpxaO5J40JyBZvD93hbel/dygf+qkHhhLR3J+kI4SDco8f8obnp3KelmmpLk93yTmx7j0krhmyDt34BDa2h7gFWzfih2EDIfJPZdOKhGrItP5v+mknfER/Eg= 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=XZKhUeS9; arc=none smtp.client-ip=209.85.128.44 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="XZKhUeS9" Received: by mail-wm1-f44.google.com with SMTP id 5b1f17b1804b1-43161c0068bso30493535e9.1; Mon, 21 Oct 2024 05:56:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1729515388; x=1730120188; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=sBrQ02u0x+gOef7QkcexjhixwvYLcPbk6l/zE/g/i1o=; b=XZKhUeS9P3Y3CoBlmhHWpilI/q5A65sHVeFSmfUgBtvw5ZmiWr+NDYKc+l2XqOW62u wI/Wn4iDNy767InY3NMdvez2QHE0GaTekIkiAYUmzmsu342rL/EGJcDUk0N1Sj5tnOxd NsIvoP0bCyyL39J3v7bJEFJSAK4AABJrF472bPLX91PmdnlRvm7qH/oSrQccYrCyV6l6 0Icg9WxmWn3QdWObQpe5/ywAFMr8hTjKwLYSecUTy/r06A5LZDKYkUym5qWSo2va/wCI rny7mhQBw3cLq4oHgIrlGWhyaHA5t2zgZc8zmgSXTC3AvlLZ1cYSbPHVzdzFRuiSeE/l Yyyw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1729515388; x=1730120188; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=sBrQ02u0x+gOef7QkcexjhixwvYLcPbk6l/zE/g/i1o=; b=SyydGuP0daHuvcvSPdlCbsOg0hnJtjjhz/nw5IY+iEEtWxCVWG3ZJNS5voBwiKgM4V kIfNCeAFFb4H3A92lXylumfeM47jxO60vBZB2Fdh3hvSeG5QRmozGC2pR2Hic6SFRwm7 ISIrRCHGH8xuEChqIZfjxreFWn5+Gkya31rLuGCkHGBL7QY6ycx1RfAFyk8sV0gR4iKK QIyh/FX6VyJ6D4TEMCj7qkaCNsS05SF3r4Br13FfULg4EqLBTQHGFuB+gr4WFSKJDktE iFfYaM2xWhKlCZmlfjPQ02Qg+meC2i/G7sMuf1abR49yjtgfeRcliaJiJiMYIhr1ktiv F77w== X-Forwarded-Encrypted: i=1; AJvYcCV0kB80zSgRMsULY+xOrb9yzle4g1AUm0vk5k1MJkg8Wse9CRYhEBEVgTpI+SIOYZao9ob8M60R0lLtAtI=@vger.kernel.org, AJvYcCWjBPSgINgQQSbe+XAQKZ4vOpQk2tlLaNjB4Iy+XYYf71Y9VrKnDM+uiBGplIc38G4gz3DR8ibXtzE=@vger.kernel.org, AJvYcCXZcjHmhLdt+41s/UZ4Vs8LqftgDROz/h6c5IQ8T5cu5zAad+mLoKCxZ/Vu2K+R2Dt215aWFd8Il4GrVQ==@vger.kernel.org X-Gm-Message-State: AOJu0Yx+9DHkGPoAKm+XzMHciwgMT9tb/kT5jDji3U/Z5Jgcrt0zjQu5 +r6mZ49Fy8jGphnpl6IC8xsJA6rD64eph6w0HtFhGwnsYPyNAMbG X-Google-Smtp-Source: AGHT+IHTdxFJmJrGfuZiT2KuSOoWNJzMyoctKdk4/SqZcCw1YvqBxoJO2n9iIQAHSDbEp9dsgXBrIw== X-Received: by 2002:a05:600c:3d9b:b0:431:5bb1:f088 with SMTP id 5b1f17b1804b1-431616a35dbmr94325905e9.29.1729515388025; Mon, 21 Oct 2024 05:56:28 -0700 (PDT) Received: from localhost (host-82-56-18-47.retail.telecomitalia.it. [82.56.18.47]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4316f5c2df7sm56628355e9.33.2024.10.21.05.56.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Oct 2024 05:56:27 -0700 (PDT) From: Matteo Martelli Date: Mon, 21 Oct 2024 14:54:16 +0200 Subject: [PATCH v5 3/5] iio: pac1921: use read_avail+release APIs instead of custom ext_info Precedence: bulk X-Mailing-List: linux-mips@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241021-iio-read-avail-release-v5-3-b168713fab33@gmail.com> References: <20241021-iio-read-avail-release-v5-0-b168713fab33@gmail.com> In-Reply-To: <20241021-iio-read-avail-release-v5-0-b168713fab33@gmail.com> To: Jonathan Cameron , Lars-Peter Clausen , Michael Hennerich , Alisa-Dariana Roman , Christian Eggers , Peter Rosin , Paul Cercueil , Sebastian Reichel Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-pm@vger.kernel.org, Matteo Martelli X-Mailer: b4 0.14.2 The pac1921 driver was exposing the available scale info via an ad-hoc ext_info attribute instead of using the read_avail API. This to avoid a possible race condition: while the available current scales were being printed to sysfs by iio core (iio_read_channel_info_avail), the shunt resistor might have been changed concurrently. Switch to the read_avail+release APIs now that the race condition has been addressed. Signed-off-by: Matteo Martelli --- drivers/iio/adc/pac1921.c | 128 ++++++++++++++++------------------------------ 1 file changed, 45 insertions(+), 83 deletions(-) diff --git a/drivers/iio/adc/pac1921.c b/drivers/iio/adc/pac1921.c index a96fae546bc1e6d1bf3a0dbe67204c191d77a3ee..f6f8f9122a78d1b5e63d8184203eb3dae55eb560 100644 --- a/drivers/iio/adc/pac1921.c +++ b/drivers/iio/adc/pac1921.c @@ -444,11 +444,52 @@ static int pac1921_read_avail(struct iio_dev *indio_dev, *vals = pac1921_int_num_samples; *length = ARRAY_SIZE(pac1921_int_num_samples); return IIO_AVAIL_LIST; + case IIO_CHAN_INFO_SCALE: + switch (chan->channel) { + case PAC1921_CHAN_VBUS: + *vals = (const int *)pac1921_vbus_scales; + *length = ARRAY_SIZE(pac1921_vbus_scales) * 2; + *type = IIO_VAL_INT_PLUS_NANO; + return IIO_AVAIL_LIST; + + case PAC1921_CHAN_VSENSE: + *vals = (const int *)pac1921_vsense_scales; + *length = ARRAY_SIZE(pac1921_vsense_scales) * 2; + *type = IIO_VAL_INT_PLUS_NANO; + return IIO_AVAIL_LIST; + + case PAC1921_CHAN_CURRENT: { + struct pac1921_priv *priv = iio_priv(indio_dev); + + *length = ARRAY_SIZE(priv->current_scales) * 2; + *type = IIO_VAL_INT_PLUS_NANO; + + guard(mutex)(&priv->lock); + + *vals = kmemdup_array((int *)priv->current_scales, + *length, sizeof(int), GFP_KERNEL); + if (!*vals) + return -ENOMEM; + + return IIO_AVAIL_LIST; + } + default: + return -EINVAL; + } default: return -EINVAL; } } +static void pac1921_read_avail_release_res(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + const int *vals, long mask) +{ + if (mask == IIO_CHAN_INFO_SCALE && + chan->channel == PAC1921_CHAN_CURRENT) + kfree(vals); +} + /* * Perform configuration update sequence: set the device into read state, then * write the config register and set the device back into integration state. @@ -748,6 +789,7 @@ static int pac1921_read_event_value(struct iio_dev *indio_dev, static const struct iio_info pac1921_iio = { .read_raw = pac1921_read_raw, .read_avail = pac1921_read_avail, + .read_avail_release_resource = pac1921_read_avail_release_res, .write_raw = pac1921_write_raw, .write_raw_get_fmt = pac1921_write_raw_get_fmt, .read_label = pac1921_read_label, @@ -805,88 +847,7 @@ static ssize_t pac1921_write_shunt_resistor(struct iio_dev *indio_dev, return len; } -/* - * Emit on sysfs the list of available scales contained in scales_tbl - * - * TODO:: this function can be replaced with iio_format_avail_list() if the - * latter will ever be exported. - * - * Must be called with lock held if the scales_tbl can change runtime (e.g. for - * the current scales table) - */ -static ssize_t pac1921_format_scale_avail(const int (*const scales_tbl)[2], - size_t size, char *buf) -{ - ssize_t len = 0; - - for (unsigned int i = 0; i < size; i++) { - if (i != 0) { - len += sysfs_emit_at(buf, len, " "); - if (len >= PAGE_SIZE) - return -EFBIG; - } - len += sysfs_emit_at(buf, len, "%d.%09d", scales_tbl[i][0], - scales_tbl[i][1]); - if (len >= PAGE_SIZE) - return -EFBIG; - } - - len += sysfs_emit_at(buf, len, "\n"); - return len; -} - -/* - * Read available scales for a specific channel - * - * NOTE: using extended info insted of iio.read_avail() because access to - * current scales must be locked as they depend on shunt resistor which may - * change runtime. Caller of iio.read_avail() would access the table unlocked - * instead. - */ -static ssize_t pac1921_read_scale_avail(struct iio_dev *indio_dev, - uintptr_t private, - const struct iio_chan_spec *chan, - char *buf) -{ - struct pac1921_priv *priv = iio_priv(indio_dev); - const int (*scales_tbl)[2]; - size_t size; - - switch (chan->channel) { - case PAC1921_CHAN_VBUS: - scales_tbl = pac1921_vbus_scales; - size = ARRAY_SIZE(pac1921_vbus_scales); - return pac1921_format_scale_avail(scales_tbl, size, buf); - - case PAC1921_CHAN_VSENSE: - scales_tbl = pac1921_vsense_scales; - size = ARRAY_SIZE(pac1921_vsense_scales); - return pac1921_format_scale_avail(scales_tbl, size, buf); - - case PAC1921_CHAN_CURRENT: { - guard(mutex)(&priv->lock); - scales_tbl = priv->current_scales; - size = ARRAY_SIZE(priv->current_scales); - return pac1921_format_scale_avail(scales_tbl, size, buf); - } - default: - return -EINVAL; - } -} - -#define PAC1921_EXT_INFO_SCALE_AVAIL { \ - .name = "scale_available", \ - .read = pac1921_read_scale_avail, \ - .shared = IIO_SEPARATE, \ -} - -static const struct iio_chan_spec_ext_info pac1921_ext_info_voltage[] = { - PAC1921_EXT_INFO_SCALE_AVAIL, - {} -}; - static const struct iio_chan_spec_ext_info pac1921_ext_info_current[] = { - PAC1921_EXT_INFO_SCALE_AVAIL, { .name = "shunt_resistor", .read = pac1921_read_shunt_resistor, @@ -910,6 +871,7 @@ static const struct iio_chan_spec pac1921_channels[] = { .type = IIO_VOLTAGE, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE), .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) | BIT(IIO_CHAN_INFO_SAMP_FREQ), @@ -927,12 +889,12 @@ static const struct iio_chan_spec pac1921_channels[] = { .indexed = 1, .event_spec = pac1921_overflow_event, .num_event_specs = ARRAY_SIZE(pac1921_overflow_event), - .ext_info = pac1921_ext_info_voltage, }, { .type = IIO_VOLTAGE, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE), .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) | BIT(IIO_CHAN_INFO_SAMP_FREQ), @@ -950,12 +912,12 @@ static const struct iio_chan_spec pac1921_channels[] = { .indexed = 1, .event_spec = pac1921_overflow_event, .num_event_specs = ARRAY_SIZE(pac1921_overflow_event), - .ext_info = pac1921_ext_info_voltage, }, { .type = IIO_CURRENT, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE), .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) | BIT(IIO_CHAN_INFO_SAMP_FREQ),