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 5B73841F342; Thu, 16 Jul 2026 12:14:37 +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=1784204077; cv=none; b=Voqg6ksGaOgqn+V7jizlRiLTruLO/ZjBh+aeSd21ZNUDV8E7LJplycL3EEOJAAwmlgu95akj9fsTAUnrmCevNeIO+VmOSTk8pyyL588oUvV9oVNDal2uEXw+ZKlX23GpUfDScIb4FTDMsvPYeo/RCb+ZYnU7bqyLjwK306CQulM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784204077; c=relaxed/simple; bh=7JOnXBt5Uceg+znMC4PaYAQtelqh4EWdpUXtslGRaws=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=r7b+ErTgcUhgCgtdP4um7jDyU4Qant+/NtQ5y7z+WCo16xymYhoa3MzmqjWxzVdnx1tcVpClC/RhDEE1sDqVos311wzGld1ceiEbzPJuRd1PZFzySgyY+oqQ+jlJn6Ly9/HoaBefr5dW5EHyXDLU65kYhBhvc6yDyl2v4CiDqBI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KLXQ+f9g; 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="KLXQ+f9g" Received: by smtp.kernel.org (Postfix) with ESMTPS id 556A4C2BD01; Thu, 16 Jul 2026 12:14:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1784204075; bh=7JOnXBt5Uceg+znMC4PaYAQtelqh4EWdpUXtslGRaws=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=KLXQ+f9gm/NpTq2lgWSwrj18lgPKVzqAKBh4vFGeMhgs3JFrVRF9lES2R7m7Hl9f3 VMF+4n/IGNfoFm8aKDEJH6Yteca1YLzI0MPlMfGCrQvK4IA9prLnrFJucgRdtO0Ydq BbX+pqGARA6FRyCPXvcsnMD9/Buci5ihYyQhWJ9wAygiJ0CmbOpvNNnNgtc7maVp5x K9ZWsAFbReaqJc0iHlXNWXuyBne9k4ewf/i21w8eZAX7+XbmhU81TICwElfaUJWvQg nNn62yLyLO1wTtVDouDZtVS9IYyeZc6BwR6UJ4r0o205yg3VgW23lPWChSSfHICwwA JUSwBANtmkdYA== 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 41A27C44518; Thu, 16 Jul 2026 12:14:35 +0000 (UTC) From: Rodrigo Alencar via B4 Relay Date: Thu, 16 Jul 2026 13:14:21 +0100 Subject: [PATCH v8 5/8] iio: dac: ad5686: implement new sync() op for the spi bus Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260716-ad5686-new-features-v8-5-ebb0051af5e5@analog.com> References: <20260716-ad5686-new-features-v8-0-ebb0051af5e5@analog.com> In-Reply-To: <20260716-ad5686-new-features-v8-0-ebb0051af5e5@analog.com> To: Michael Auchter , linux@analog.com, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Cc: Michael Hennerich , Jonathan Cameron , David Lechner , Andy Shevchenko , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Philipp Zabel , Kees Cook , "Gustavo A. R. Silva" , Rodrigo Alencar X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1784204073; l=9505; i=rodrigo.alencar@analog.com; s=default; h=from:subject:message-id; bh=AlwspQRkwDSA9AHYk4gXvnKk5HKxLG5jsm50VTcbJNM=; b=zxViWUxI9fAeJXSHsDgxUUxkpolj07Eom4PNKNT5AYKJU2K7gxwrs8tbbMs+8wnBnio/FUhlR TttUntgD7lPDxYbCgxlgxGhG1c3CN7EAOGqC5nF1G1Uxns4kJMyVaYH X-Developer-Key: i=rodrigo.alencar@analog.com; a=ed25519; pk=ULeHbgU/OYh/PG/4anHDfLgldFItQHAhOktYRVLMFRo= X-Endpoint-Received: by B4 Relay for rodrigo.alencar@analog.com/default with auth_id=561 X-Original-From: Rodrigo Alencar Reply-To: rodrigo.alencar@analog.com From: Rodrigo Alencar Use of local SPI bus data to manage a collection of SPI transfers and flush them to the SPI platform driver with the sync() operation. This allows for faster handling of multiple channel DAC writes, avoiding kernel overhead per spi_sync() call, which will be helpful when enabling triggered buffer support. For consistency, the read operation leverages the same transfer data rather than a stack-allocated array. Reviewed-by: David Lechner Signed-off-by: Rodrigo Alencar --- drivers/iio/dac/ad5686-spi.c | 135 +++++++++++++++++++++++++++++++++---------- drivers/iio/dac/ad5686.c | 4 +- drivers/iio/dac/ad5686.h | 8 ++- drivers/iio/dac/ad5696-i2c.c | 2 +- 4 files changed, 114 insertions(+), 35 deletions(-) diff --git a/drivers/iio/dac/ad5686-spi.c b/drivers/iio/dac/ad5686-spi.c index d3b64b4361d5..2cb836038821 100644 --- a/drivers/iio/dac/ad5686-spi.c +++ b/drivers/iio/dac/ad5686-spi.c @@ -13,59 +13,101 @@ #include #include #include +#include #include #include #include "ad5686.h" +/** + * struct ad5686_spi_data - SPI bus specific data + * @msg: SPI message used for transfers + * @size: number of transfers currently in the message + * @capacity: maximum number of transfers that can be added to the message + * @xfers: array of SPI transfers, allocated with the provided capacity + */ +struct ad5686_spi_data { + struct spi_message msg; + unsigned int size; + unsigned int capacity; + struct spi_transfer xfers[] __counted_by(capacity); +}; + static int ad5686_spi_write(struct ad5686_state *st, u8 cmd, u8 addr, u16 val) { - struct spi_device *spi = to_spi_device(st->dev); - u8 tx_len, *buf; + struct ad5686_spi_data *bus_data = st->bus_data; + struct spi_transfer *xfer; + if (bus_data->size >= bus_data->capacity) + return -E2BIG; + + /* + * This function stores spi transfers to a spi message to be sent over + * the bus when sync() op is called. If there are already transfers in + * the spi message, set the cs_change flag on the last transfer to + * ensure that the chip select is deasserted between transfers. If this + * is the first transfer, initialize the spi message. Later on, the + * current transfer is added to the message with spi_message_add_tail(). + */ + if (bus_data->size) + bus_data->xfers[bus_data->size - 1].cs_change = 1; + else + spi_message_init(&bus_data->msg); + + xfer = &bus_data->xfers[bus_data->size]; + auto buf = &st->data[bus_data->size]; switch (st->chip_info->regmap_type) { case AD5310_REGMAP: - st->data[0].d16 = cpu_to_be16(FIELD_PREP(AD5310_CMD_MSK, cmd) | - FIELD_PREP(AD5310_DATA_MSK, val)); - buf = &st->data[0].d8[0]; - tx_len = 2; + buf->d16 = cpu_to_be16(FIELD_PREP(AD5310_CMD_MSK, cmd) | + FIELD_PREP(AD5310_DATA_MSK, val)); + *xfer = (struct spi_transfer) { + .tx_buf = &buf->d16, + .len = sizeof(buf->d16), + }; break; case AD5683_REGMAP: - st->data[0].d32 = cpu_to_be32(FIELD_PREP(AD5686_CMD_MSK, cmd) | - FIELD_PREP(AD5683_DATA_MSK, val)); - buf = &st->data[0].d8[1]; - tx_len = 3; + buf->d32 = cpu_to_be32(FIELD_PREP(AD5686_CMD_MSK, cmd) | + FIELD_PREP(AD5683_DATA_MSK, val)); + *xfer = (struct spi_transfer) { + .tx_buf = &buf->d8[1], + .len = sizeof(buf->d8) - 1, + }; break; case AD5686_REGMAP: - st->data[0].d32 = cpu_to_be32(FIELD_PREP(AD5686_CMD_MSK, cmd) | - FIELD_PREP(AD5686_ADDR_MSK, addr) | - FIELD_PREP(AD5686_DATA_MSK, val)); - buf = &st->data[0].d8[1]; - tx_len = 3; + buf->d32 = cpu_to_be32(FIELD_PREP(AD5686_CMD_MSK, cmd) | + FIELD_PREP(AD5686_ADDR_MSK, addr) | + FIELD_PREP(AD5686_DATA_MSK, val)); + *xfer = (struct spi_transfer) { + .tx_buf = &buf->d8[1], + .len = sizeof(buf->d8) - 1, + }; break; default: return -EINVAL; } - return spi_write(spi, buf, tx_len); + spi_message_add_tail(xfer, &bus_data->msg); + bus_data->size++; + + return 0; +} + +static int ad5686_spi_sync(struct ad5686_state *st) +{ + struct spi_device *spi = to_spi_device(st->dev); + struct ad5686_spi_data *bus_data = st->bus_data; + + bus_data->size = 0; /* always reset, even on sync failure */ + return spi_sync(spi, &bus_data->msg); } static int ad5686_spi_read(struct ad5686_state *st, u8 addr) { - struct spi_transfer t[] = { - { - .tx_buf = &st->data[0].d8[1], - .len = 3, - .cs_change = 1, - }, { - .tx_buf = &st->data[1].d8[1], - .rx_buf = &st->data[2].d8[1], - .len = 3, - }, - }; struct spi_device *spi = to_spi_device(st->dev); + struct ad5686_spi_data *bus_data = st->bus_data; + struct spi_transfer *xfer = &bus_data->xfers[0]; u8 cmd = 0; int ret; @@ -86,8 +128,21 @@ static int ad5686_spi_read(struct ad5686_state *st, u8 addr) FIELD_PREP(AD5686_ADDR_MSK, addr)); st->data[1].d32 = cpu_to_be32(FIELD_PREP(AD5686_CMD_MSK, AD5686_CMD_NOOP)); - ret = spi_sync_transfer(spi, t, ARRAY_SIZE(t)); - if (ret < 0) + xfer[0] = (struct spi_transfer) { + .tx_buf = &st->data[0].d8[1], + .len = sizeof(st->data[0].d8) - 1, + .cs_change = 1, + }; + xfer[1] = (struct spi_transfer) { + .tx_buf = &st->data[1].d8[1], + .rx_buf = &st->data[2].d8[1], + .len = sizeof(st->data[1].d8) - 1, + }; + + spi_message_init_with_transfers(&bus_data->msg, xfer, 2); + + ret = spi_sync(spi, &bus_data->msg); + if (ret) return ret; return be32_to_cpu(st->data[2].d32); @@ -96,12 +151,30 @@ static int ad5686_spi_read(struct ad5686_state *st, u8 addr) static const struct ad5686_bus_ops ad5686_spi_ops = { .write = ad5686_spi_write, .read = ad5686_spi_read, + .sync = ad5686_spi_sync, }; static int ad5686_spi_probe(struct spi_device *spi) { - return ad5686_probe(&spi->dev, spi_get_device_match_data(spi), - spi->modalias, &ad5686_spi_ops); + const struct ad5686_chip_info *info; + struct ad5686_spi_data *bus_data; + struct device *dev = &spi->dev; + unsigned int capacity; + + info = spi_get_device_match_data(spi); + if (!info) + return -ENODEV; + + /* read operation requires at least 2 transfers */ + capacity = max(info->num_channels, 2); + bus_data = devm_kzalloc(dev, struct_size(bus_data, xfers, capacity), + GFP_KERNEL); + if (!bus_data) + return -ENOMEM; + + bus_data->capacity = capacity; + + return ad5686_probe(dev, info, spi->modalias, &ad5686_spi_ops, bus_data); } static const struct spi_device_id ad5686_spi_id[] = { diff --git a/drivers/iio/dac/ad5686.c b/drivers/iio/dac/ad5686.c index c285aeed44d1..67cd581a24c5 100644 --- a/drivers/iio/dac/ad5686.c +++ b/drivers/iio/dac/ad5686.c @@ -472,7 +472,8 @@ EXPORT_SYMBOL_NS_GPL(ad5679r_chip_info, "IIO_AD5686"); int ad5686_probe(struct device *dev, const struct ad5686_chip_info *chip_info, - const char *name, const struct ad5686_bus_ops *ops) + const char *name, const struct ad5686_bus_ops *ops, + void *bus_data) { struct reset_control *rstc; struct ad5686_state *st; @@ -490,6 +491,7 @@ int ad5686_probe(struct device *dev, st->dev = dev; st->ops = ops; + st->bus_data = bus_data; st->chip_info = chip_info; rstc = devm_reset_control_get_optional_exclusive(dev, NULL); diff --git a/drivers/iio/dac/ad5686.h b/drivers/iio/dac/ad5686.h index ae9aeda2d201..2c3d7d5b1d6b 100644 --- a/drivers/iio/dac/ad5686.h +++ b/drivers/iio/dac/ad5686.h @@ -25,6 +25,7 @@ #define AD5686_ADDR_DAC(chan) (0x1 << (chan)) #define AD5686_ADDR_ALL_DAC 0xF +#define AD5686_MAX_CHANNELS 16 #define AD5686_CMD_NOOP 0x0 #define AD5686_CMD_WRITE_INPUT_N 0x1 @@ -132,6 +133,7 @@ extern const struct ad5686_chip_info ad5679r_chip_info; * @use_internal_vref: set to true if the internal reference voltage is used * @lock: lock to protect access to state fields, which includes * the data buffer during regmap ops + * @bus_data: bus specific data * @data: transfer buffers */ struct ad5686_state { @@ -144,6 +146,7 @@ struct ad5686_state { unsigned int pwr_down_mode; bool use_internal_vref; struct mutex lock; + void *bus_data; /* * DMA (thus cache coherency maintenance) may require the @@ -154,13 +157,14 @@ struct ad5686_state { __be32 d32; __be16 d16; u8 d8[4]; - } data[3] __aligned(IIO_DMA_MINALIGN); + } data[AD5686_MAX_CHANNELS] __aligned(IIO_DMA_MINALIGN); }; int ad5686_probe(struct device *dev, const struct ad5686_chip_info *chip_info, - const char *name, const struct ad5686_bus_ops *ops); + const char *name, const struct ad5686_bus_ops *ops, + void *bus_data); static inline int ad5686_write(struct ad5686_state *st, u8 cmd, u8 addr, u16 val) { diff --git a/drivers/iio/dac/ad5696-i2c.c b/drivers/iio/dac/ad5696-i2c.c index 2c95d394a1c0..94ad23d2228f 100644 --- a/drivers/iio/dac/ad5696-i2c.c +++ b/drivers/iio/dac/ad5696-i2c.c @@ -74,7 +74,7 @@ static const struct ad5686_bus_ops ad5686_i2c_ops = { static int ad5686_i2c_probe(struct i2c_client *i2c) { return ad5686_probe(&i2c->dev, i2c_get_match_data(i2c), - i2c->name, &ad5686_i2c_ops); + i2c->name, &ad5686_i2c_ops, NULL); } static const struct i2c_device_id ad5686_i2c_id[] = { -- 2.43.0