From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E05CF32470E; Mon, 18 May 2026 09:59:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779098345; cv=none; b=AtbcB14gf23AAAGvtZKMrmfTM2BuvAc6L7KM/EajfxSChHzHR635NBuCOEgULkojoSmNixxFA+amwaau6ADKE+Kd7teKe6TraQOQgLYWq9KFAU+KLOVAFklHwPQa2iLIJa97u7UyY2AvNFL5TVe0K7piXBGz7Tb6rDhdTt1m2kQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779098345; c=relaxed/simple; bh=mKnRuldEhWQktUtIa6WmCvZZ2JFy+d/Hp5jzI0nvrYM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Mg3U+6GNyjT5vnEsGfQVDnF1gYiHD6T+AxtLn4Vg8vouAXpCdVbFaLF3/Gi1VBf9Un/Wv+lRwcTAKX2qTGlpgi/8D1ZY0JaiY5of8EvzMVClgA1OhHek4ipIfNyaMpDrtgxlrdegrr1HvNDZ4ero67HYdc49fZNsfneAZfvo+vM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TU6iM1Ly; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TU6iM1Ly" Received: by smtp.kernel.org (Postfix) with ESMTPS id A69FBC2BCF6; Mon, 18 May 2026 09:59:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1779098344; bh=mKnRuldEhWQktUtIa6WmCvZZ2JFy+d/Hp5jzI0nvrYM=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=TU6iM1LyEVGi3QpL1osaTzKSK1jAhkaB83DfiArmqtS0MnLkmTiGGkOi8e12mFdkD 3NRpRJFPMtQFCprhftv2HlVRiVzxUe4M44m/O3j1qikRsCIeUcBy8DO5AU0hRHImnv A7g0TCdI5+EZdkhVXNCBkmc28LaeHDiRGXqzOYQw9Cmr8LwsfQLw9lTJzfrH71wMCl s4QZ00Y5eUvbzrecKZI6sbwMmJ/QAd0nSKfU2tFfpLaow01EsbuxYrOWPF/oPX26mU 57475vri9juPKJol3cxdggHKN4yRRRKRK2StU9iCKYdUyYYwULH6TqWSDwO8yRAM8P Be8IO1Jhzv2eQ== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9B19FCD4F52; Mon, 18 May 2026 09:59:04 +0000 (UTC) From: Radu Sabau via B4 Relay Date: Mon, 18 May 2026 12:59:04 +0300 Subject: [PATCH v3 2/2] iio: adc: ad_sigma_delta: fix clear_pending_event for registerless devices Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Message-Id: <20260518-ad_sigma_delta-fix-v3-2-a2a92b0c36f3@analog.com> References: <20260518-ad_sigma_delta-fix-v3-0-a2a92b0c36f3@analog.com> In-Reply-To: <20260518-ad_sigma_delta-fix-v3-0-a2a92b0c36f3@analog.com> To: Lars-Peter Clausen , Michael Hennerich , Jonathan Cameron , David Lechner , =?utf-8?q?Nuno_S=C3=A1?= , Andy Shevchenko , =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Radu Sabau , Jonathan Cameron X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1779098343; l=3198; i=radu.sabau@analog.com; s=20260220; h=from:subject:message-id; bh=ik2MMWjPIciaEPWACoIeOi+XWz2Jq+3CxsOakr8Y31w=; b=mjtWt97UmSf1N+y14ywsO1BC0YuGZlRbohpvwDZ96pDVYmkrMh7+Iel+jWLecvhbAPlDtolil LQLh6qlasfTCE2n0CY8Rl649E+lt60a8vbR0Rg3+MWhsPsomPcWZBso X-Developer-Key: i=radu.sabau@analog.com; a=ed25519; pk=lDPQHgn9jTdt0vo58Na9lLxLaE2mb330if71Cn+EvFU= X-Endpoint-Received: by B4 Relay for radu.sabau@analog.com/20260220 with auth_id=642 X-Original-From: Radu Sabau Reply-To: radu.sabau@analog.com From: Radu Sabau ad_sigma_delta_clear_pending_event() falls through to the status register read path for devices with has_registers = false and no rdy_gpiod. For such devices, ad_sd_read_reg() skips the address byte entirely and clocks raw MISO bytes with no address phase — making it byte-for-byte identical to reading conversion data. If a pending conversion result is present, this partially consumes it and corrupts the data stream for the subsequent ad_sd_read_reg() call in ad_sigma_delta_single_conversion(). Furthermore, with num_resetclks = 0 on these devices, data_read_len evaluates to 0. If the clocked byte has bit 7 clear, pending_event is set and the code attempts memset(data + 2, 0xff, 0 - 1), overflowing to SIZE_MAX and corrupting the heap. Fix by returning 0 immediately when neither rdy_gpiod nor has_registers is set. This is safe because the IRQ is requested with IRQF_NO_AUTOEN and IRQ_DISABLE_UNLAZY, which keeps the hardware IRQ line unmasked even while software-disabled. Any falling edge from a completed conversion is latched by the IRQ controller. When ad_sd_enable_irq() is subsequently called the latched edge fires immediately, and the existing ad_sd_read_reg() call in ad_sigma_delta_single_conversion() reads the complete stale result from the beginning with no prior partial clock corruption. Signed-off-by: Radu Sabau --- drivers/iio/adc/ad_sigma_delta.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c index a33a7e8c264f..88dcaa910b2d 100644 --- a/drivers/iio/adc/ad_sigma_delta.c +++ b/drivers/iio/adc/ad_sigma_delta.c @@ -262,11 +262,16 @@ static int ad_sigma_delta_clear_pending_event(struct ad_sigma_delta *sigma_delta /* * Read R̅D̅Y̅ pin (if possible) or status register to check if there is an - * old event. + * old event. For devices with neither an RDY GPIO nor registers, + * ad_sd_read_reg() transmits no address byte and clocks raw MISO bytes, + * which is indistinguishable from reading conversion data and would + * partially consume a pending result. Skip the check for such devices; + * IRQ_DISABLE_UNLAZY ensures any pending falling edge is latched and + * fires naturally on the next ad_sd_enable_irq() call. */ if (sigma_delta->rdy_gpiod) { pending_event = gpiod_get_value(sigma_delta->rdy_gpiod); - } else { + } else if (sigma_delta->info->has_registers) { unsigned int status_reg; ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_STATUS, 1, &status_reg); @@ -274,6 +279,8 @@ static int ad_sigma_delta_clear_pending_event(struct ad_sigma_delta *sigma_delta return ret; pending_event = !(status_reg & AD_SD_REG_STATUS_RDY); + } else { + return 0; } if (!pending_event) @@ -578,6 +585,7 @@ static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) err_unlock: sigma_delta->keep_cs_asserted = false; + ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); sigma_delta->bus_locked = false; spi_bus_unlock(sigma_delta->spi->controller); spi_unoptimize_message(&sigma_delta->sample_msg); -- 2.43.0