From a5251cd9614cf2ac24a513359b5265b44605cf82 Mon Sep 17 00:00:00 2001 From: "Ricardo B. Marliere" Date: Sun, 4 Feb 2024 17:55:22 -0300 Subject: [PATCH 1/8] w1: make w1_bus_type const Now that the driver core can properly handle constant struct bus_type, move the w1_bus_type variable to be a constant structure as well, placing it into read-only memory which can not be modified at runtime. Cc: Greg Kroah-Hartman Suggested-by: Greg Kroah-Hartman Signed-off-by: Ricardo B. Marliere Link: https://lore.kernel.org/r/20240204-bus_cleanup-w1-v1-1-a0f4c84d7db3@marliere.net Signed-off-by: Krzysztof Kozlowski --- drivers/w1/w1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index 5353cbd75126..afb1cc4606c5 100644 --- a/drivers/w1/w1.c +++ b/drivers/w1/w1.c @@ -167,7 +167,7 @@ static struct w1_family w1_default_family = { static int w1_uevent(const struct device *dev, struct kobj_uevent_env *env); -static struct bus_type w1_bus_type = { +static const struct bus_type w1_bus_type = { .name = "w1", .uevent = w1_uevent, }; From 12d2a81c57042337b68ef7d1b400a6f2b707dc94 Mon Sep 17 00:00:00 2001 From: Christoph Winklhofer Date: Fri, 9 Feb 2024 07:22:37 +0100 Subject: [PATCH 2/8] dt-bindings: serial: allow onewire as child node The UART 1-Wire bus utilizes the Serial Device Bus to create the 1-wire timing patterns. Acked-by: Rob Herring Signed-off-by: Christoph Winklhofer Link: https://lore.kernel.org/r/20240209-w1-uart-v6-1-3e753c149196@gmail.com Signed-off-by: Krzysztof Kozlowski --- Documentation/devicetree/bindings/serial/serial.yaml | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/serial/serial.yaml b/Documentation/devicetree/bindings/serial/serial.yaml index 65804ca274ae..ffc9198ae214 100644 --- a/Documentation/devicetree/bindings/serial/serial.yaml +++ b/Documentation/devicetree/bindings/serial/serial.yaml @@ -88,7 +88,7 @@ properties: TX FIFO threshold configuration (in bytes). patternProperties: - "^(bluetooth|bluetooth-gnss|gnss|gps|mcu)$": + "^(bluetooth|bluetooth-gnss|gnss|gps|mcu|onewire)$": if: type: object then: From 23b333375317f6c2866e1ede7e7c4a726fc22aa8 Mon Sep 17 00:00:00 2001 From: Christoph Winklhofer Date: Fri, 9 Feb 2024 07:22:38 +0100 Subject: [PATCH 3/8] dt-bindings: w1: UART 1-Wire bus Add device tree binding for UART 1-Wire bus. Reviewed-by: Rob Herring Signed-off-by: Christoph Winklhofer Link: https://lore.kernel.org/r/20240209-w1-uart-v6-2-3e753c149196@gmail.com Signed-off-by: Krzysztof Kozlowski --- .../devicetree/bindings/w1/w1-uart.yaml | 59 +++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 Documentation/devicetree/bindings/w1/w1-uart.yaml diff --git a/Documentation/devicetree/bindings/w1/w1-uart.yaml b/Documentation/devicetree/bindings/w1/w1-uart.yaml new file mode 100644 index 000000000000..bd7c62d780b8 --- /dev/null +++ b/Documentation/devicetree/bindings/w1/w1-uart.yaml @@ -0,0 +1,59 @@ +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/w1/w1-uart.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: UART 1-Wire Bus + +maintainers: + - Christoph Winklhofer + +description: | + UART 1-wire bus. Utilizes the UART interface via the Serial Device Bus + to create the 1-Wire timing patterns. + + The UART peripheral must support full-duplex and operate in open-drain + mode. The timing patterns are generated by a specific combination of + baud-rate and transmitted byte, which corresponds to a 1-Wire read bit, + write bit or reset pulse. + + The default baud-rate for reset and presence detection is 9600 and for + a 1-Wire read or write operation 115200. In case the actual baud-rate + is different from the requested one, the transmitted byte is adapted + to generate the 1-Wire timing patterns. + + https://www.analog.com/en/technical-articles/using-a-uart-to-implement-a-1wire-bus-master.html + +properties: + compatible: + const: w1-uart + + reset-bps: + default: 9600 + description: + The baud rate for the 1-Wire reset and presence detect. + + write-0-bps: + default: 115200 + description: + The baud rate for the 1-Wire write-0 cycle. + + write-1-bps: + default: 115200 + description: + The baud rate for the 1-Wire write-1 and read cycle. + +required: + - compatible + +additionalProperties: + type: object + +examples: + - | + serial { + onewire { + compatible = "w1-uart"; + }; + }; From a3c08804364e80328a9ffdac59bb26676b938195 Mon Sep 17 00:00:00 2001 From: Christoph Winklhofer Date: Wed, 14 Feb 2024 07:36:15 +0100 Subject: [PATCH 4/8] w1: add UART w1 bus driver Add a UART 1-Wire bus driver. The driver utilizes the UART interface via the Serial Device Bus to create the 1-Wire timing patterns. The driver was tested on a "Raspberry Pi 3B" with a DS18B20 and on a "Variscite DART-6UL" with a DS18S20 temperature sensor. The 1-Wire timing pattern and the corresponding UART baud-rate with the interpretation of the transferred bytes are described in the document: Link: https://www.analog.com/en/technical-articles/using-a-uart-to-implement-a-1wire-bus-master.html In short, the UART peripheral must support full-duplex and operate in open-drain mode. The timing patterns are generated by a specific combination of baud-rate and transmitted byte, which corresponds to a 1-Wire read bit, write bit or reset. Signed-off-by: Christoph Winklhofer Link: https://lore.kernel.org/r/20240214-w1-uart-v7-3-6e21fa24e066@gmail.com [krzysztof: w1_uart_serdev_receive_buf() return type fixup] Signed-off-by: Krzysztof Kozlowski --- Documentation/w1/masters/index.rst | 1 + Documentation/w1/masters/w1-uart.rst | 54 ++++ drivers/w1/masters/Kconfig | 10 + drivers/w1/masters/Makefile | 1 + drivers/w1/masters/w1-uart.c | 415 +++++++++++++++++++++++++++ 5 files changed, 481 insertions(+) create mode 100644 Documentation/w1/masters/w1-uart.rst create mode 100644 drivers/w1/masters/w1-uart.c diff --git a/Documentation/w1/masters/index.rst b/Documentation/w1/masters/index.rst index 4442a98850ad..cc40189909fd 100644 --- a/Documentation/w1/masters/index.rst +++ b/Documentation/w1/masters/index.rst @@ -12,3 +12,4 @@ mxc-w1 omap-hdq w1-gpio + w1-uart diff --git a/Documentation/w1/masters/w1-uart.rst b/Documentation/w1/masters/w1-uart.rst new file mode 100644 index 000000000000..8d0f122178d4 --- /dev/null +++ b/Documentation/w1/masters/w1-uart.rst @@ -0,0 +1,54 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +===================== +Kernel driver w1-uart +===================== + +Author: Christoph Winklhofer + + +Description +----------- + +UART 1-Wire bus driver. The driver utilizes the UART interface via the +Serial Device Bus to create the 1-Wire timing patterns as described in +the document `"Using a UART to Implement a 1-Wire Bus Master"`_. + +.. _"Using a UART to Implement a 1-Wire Bus Master": https://www.analog.com/en/technical-articles/using-a-uart-to-implement-a-1wire-bus-master.html + +In short, the UART peripheral must support full-duplex and operate in +open-drain mode. The timing patterns are generated by a specific +combination of baud-rate and transmitted byte, which corresponds to a +1-Wire read bit, write bit or reset pulse. + +For instance the timing pattern for a 1-Wire reset and presence detect uses +the baud-rate 9600, i.e. 104.2 us per bit. The transmitted byte 0xf0 over +UART (least significant bit first, start-bit low) sets the reset low time +for 1-Wire to 521 us. A present 1-Wire device changes the received byte by +pulling the line low, which is used by the driver to evaluate the result of +the 1-Wire operation. + +Similar for a 1-Wire read bit or write bit, which uses the baud-rate +115200, i.e. 8.7 us per bit. The transmitted byte 0x80 is used for a +Write-0 operation (low time 69.6us) and the byte 0xff for Read-0, Read-1 +and Write-1 (low time 8.7us). + +The default baud-rate for reset and presence detection is 9600 and for +a 1-Wire read or write operation 115200. In case the actual baud-rate +is different from the requested one, the transmitted byte is adapted +to generate the 1-Wire timing patterns. + + +Usage +----- + +Specify the UART 1-wire bus in the device tree by adding the single child +onewire to the serial node (e.g. uart0). For example: +:: + + @uart0 { + ... + onewire { + compatible = "w1-uart"; + }; + }; diff --git a/drivers/w1/masters/Kconfig b/drivers/w1/masters/Kconfig index 513c0b114337..e6049a75b35b 100644 --- a/drivers/w1/masters/Kconfig +++ b/drivers/w1/masters/Kconfig @@ -78,5 +78,15 @@ config W1_MASTER_SGI This support is also available as a module. If so, the module will be called sgi_w1. +config W1_MASTER_UART + tristate "UART 1-wire driver" + depends on SERIAL_DEV_BUS + help + Say Y here if you want to communicate with your 1-wire devices using + UART interface. + + This support is also available as a module. If so, the module + will be called w1-uart. + endmenu diff --git a/drivers/w1/masters/Makefile b/drivers/w1/masters/Makefile index 6c5a21f9b88c..227f80987e69 100644 --- a/drivers/w1/masters/Makefile +++ b/drivers/w1/masters/Makefile @@ -12,3 +12,4 @@ obj-$(CONFIG_W1_MASTER_MXC) += mxc_w1.o obj-$(CONFIG_W1_MASTER_GPIO) += w1-gpio.o obj-$(CONFIG_HDQ_MASTER_OMAP) += omap_hdq.o obj-$(CONFIG_W1_MASTER_SGI) += sgi_w1.o +obj-$(CONFIG_W1_MASTER_UART) += w1-uart.o diff --git a/drivers/w1/masters/w1-uart.c b/drivers/w1/masters/w1-uart.c new file mode 100644 index 000000000000..a31782e56ba7 --- /dev/null +++ b/drivers/w1/masters/w1-uart.c @@ -0,0 +1,415 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * w1-uart - UART 1-Wire bus driver + * + * Uses the UART interface (via Serial Device Bus) to create the 1-Wire + * timing patterns. Implements the following 1-Wire master interface: + * + * - reset_bus: requests baud-rate 9600 + * + * - touch_bit: requests baud-rate 115200 + * + * Author: Christoph Winklhofer + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +/* UART packet contains start and stop bit */ +#define W1_UART_BITS_PER_PACKET (BITS_PER_BYTE + 2) + +/* Timeout to wait for completion of serdev-receive */ +#define W1_UART_TIMEOUT msecs_to_jiffies(500) + +/** + * struct w1_uart_config - configuration for 1-Wire operation + * @baudrate: baud-rate returned from serdev + * @delay_us: delay to complete a 1-Wire cycle (in us) + * @tx_byte: byte to generate 1-Wire timing pattern + */ +struct w1_uart_config { + unsigned int baudrate; + unsigned int delay_us; + u8 tx_byte; +}; + +/** + * struct w1_uart_device - 1-Wire UART device structure + * @serdev: serial device + * @bus: w1-bus master + * @cfg_reset: config for 1-Wire reset + * @cfg_touch_0: config for 1-Wire write-0 cycle + * @cfg_touch_1: config for 1-Wire write-1 and read cycle + * @rx_byte_received: completion for serdev receive + * @rx_mutex: mutex to protect rx_err and rx_byte + * @rx_err: indicates an error in serdev-receive + * @rx_byte: result byte from serdev-receive + */ +struct w1_uart_device { + struct serdev_device *serdev; + struct w1_bus_master bus; + + struct w1_uart_config cfg_reset; + struct w1_uart_config cfg_touch_0; + struct w1_uart_config cfg_touch_1; + + struct completion rx_byte_received; + /* + * protect rx_err and rx_byte from concurrent access in + * w1-callbacks and serdev-receive. + */ + struct mutex rx_mutex; + int rx_err; + u8 rx_byte; +}; + +/** + * struct w1_uart_limits - limits for 1-Wire operations + * @baudrate: Requested baud-rate to create 1-Wire timing pattern + * @bit_min_us: minimum time for a bit (in us) + * @bit_max_us: maximum time for a bit (in us) + * @sample_us: timespan to sample 1-Wire response + * @cycle_us: duration of the 1-Wire cycle + */ +struct w1_uart_limits { + unsigned int baudrate; + unsigned int bit_min_us; + unsigned int bit_max_us; + unsigned int sample_us; + unsigned int cycle_us; +}; + +static inline unsigned int baud_to_bit_ns(unsigned int baud) +{ + return NSEC_PER_SEC / baud; +} + +static inline unsigned int to_ns(unsigned int us) +{ + return us * NSEC_PER_USEC; +} + +/* + * Set baud-rate, delay and tx-byte to create a 1-Wire pulse and adapt + * the tx-byte according to the actual baud-rate. + * + * Reject when: + * - time for a bit outside min/max range + * - a 1-Wire response is not detectable for sent byte + */ +static int w1_uart_set_config(struct serdev_device *serdev, + const struct w1_uart_limits *limits, + struct w1_uart_config *w1cfg) +{ + unsigned int packet_ns; + unsigned int bits_low; + unsigned int bit_ns; + unsigned int low_ns; + + w1cfg->baudrate = serdev_device_set_baudrate(serdev, limits->baudrate); + if (w1cfg->baudrate == 0) + return -EINVAL; + + /* Compute in nanoseconds for accuracy */ + bit_ns = baud_to_bit_ns(w1cfg->baudrate); + bits_low = to_ns(limits->bit_min_us) / bit_ns; + /* start bit is always low */ + low_ns = bit_ns * (bits_low + 1); + + if (low_ns < to_ns(limits->bit_min_us)) + return -EINVAL; + + if (low_ns > to_ns(limits->bit_max_us)) + return -EINVAL; + + /* 1-Wire response detectable for sent byte */ + if (limits->sample_us > 0 && + bit_ns * BITS_PER_BYTE < low_ns + to_ns(limits->sample_us)) + return -EINVAL; + + /* delay: 1-Wire cycle takes longer than the UART packet */ + packet_ns = bit_ns * W1_UART_BITS_PER_PACKET; + w1cfg->delay_us = 0; + if (to_ns(limits->cycle_us) > packet_ns) + w1cfg->delay_us = + (to_ns(limits->cycle_us) - packet_ns) / NSEC_PER_USEC; + + /* byte to create 1-Wire pulse */ + w1cfg->tx_byte = 0xff << bits_low; + + return 0; +} + +/* + * Configuration for reset and presence detect + * - bit_min_us is 480us, add margin and use 485us + * - limits for sample time 60us-75us, use 65us + */ +static int w1_uart_set_config_reset(struct w1_uart_device *w1dev) +{ + struct serdev_device *serdev = w1dev->serdev; + struct device_node *np = serdev->dev.of_node; + + struct w1_uart_limits limits = { .baudrate = 9600, + .bit_min_us = 485, + .bit_max_us = 640, + .sample_us = 65, + .cycle_us = 960 }; + + of_property_read_u32(np, "reset-bps", &limits.baudrate); + + return w1_uart_set_config(serdev, &limits, &w1dev->cfg_reset); +} + +/* + * Configuration for write-0 cycle (touch bit 0) + * - bit_min_us is 60us, add margin and use 65us + * - no sampling required, sample_us = 0 + */ +static int w1_uart_set_config_touch_0(struct w1_uart_device *w1dev) +{ + struct serdev_device *serdev = w1dev->serdev; + struct device_node *np = serdev->dev.of_node; + + struct w1_uart_limits limits = { .baudrate = 115200, + .bit_min_us = 65, + .bit_max_us = 120, + .sample_us = 0, + .cycle_us = 70 }; + + of_property_read_u32(np, "write-0-bps", &limits.baudrate); + + return w1_uart_set_config(serdev, &limits, &w1dev->cfg_touch_0); +} + +/* + * Configuration for write-1 and read cycle (touch bit 1) + * - bit_min_us is 5us, add margin and use 6us + * - limits for sample time 5us-15us, use 15us + */ +static int w1_uart_set_config_touch_1(struct w1_uart_device *w1dev) +{ + struct serdev_device *serdev = w1dev->serdev; + struct device_node *np = serdev->dev.of_node; + + struct w1_uart_limits limits = { .baudrate = 115200, + .bit_min_us = 6, + .bit_max_us = 15, + .sample_us = 15, + .cycle_us = 70 }; + + of_property_read_u32(np, "write-1-bps", &limits.baudrate); + + return w1_uart_set_config(serdev, &limits, &w1dev->cfg_touch_1); +} + +/* + * Configure and open the serial device + */ +static int w1_uart_serdev_open(struct w1_uart_device *w1dev) +{ + struct serdev_device *serdev = w1dev->serdev; + struct device *dev = &serdev->dev; + int ret; + + ret = devm_serdev_device_open(dev, serdev); + if (ret < 0) + return ret; + + ret = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE); + if (ret < 0) { + dev_err(dev, "set parity failed\n"); + return ret; + } + + ret = w1_uart_set_config_reset(w1dev); + if (ret < 0) { + dev_err(dev, "config for reset failed\n"); + return ret; + } + + ret = w1_uart_set_config_touch_0(w1dev); + if (ret < 0) { + dev_err(dev, "config for touch-0 failed\n"); + return ret; + } + + ret = w1_uart_set_config_touch_1(w1dev); + if (ret < 0) { + dev_err(dev, "config for touch-1 failed\n"); + return ret; + } + + serdev_device_set_flow_control(serdev, false); + + return 0; +} + +/* + * Send one byte (tx_byte) and read one byte (rx_byte) via serdev. + */ +static int w1_uart_serdev_tx_rx(struct w1_uart_device *w1dev, + const struct w1_uart_config *w1cfg, u8 *rx_byte) +{ + struct serdev_device *serdev = w1dev->serdev; + int ret; + + serdev_device_write_flush(serdev); + serdev_device_set_baudrate(serdev, w1cfg->baudrate); + + /* write and immediately read one byte */ + reinit_completion(&w1dev->rx_byte_received); + ret = serdev_device_write_buf(serdev, &w1cfg->tx_byte, 1); + if (ret != 1) + return -EIO; + ret = wait_for_completion_interruptible_timeout( + &w1dev->rx_byte_received, W1_UART_TIMEOUT); + if (ret <= 0) + return -EIO; + + /* locking could fail when serdev is unexpectedly receiving. */ + if (!mutex_trylock(&w1dev->rx_mutex)) + return -EIO; + + ret = w1dev->rx_err; + if (ret == 0) + *rx_byte = w1dev->rx_byte; + + mutex_unlock(&w1dev->rx_mutex); + + if (w1cfg->delay_us > 0) + fsleep(w1cfg->delay_us); + + return ret; +} + +static size_t w1_uart_serdev_receive_buf(struct serdev_device *serdev, + const u8 *buf, size_t count) +{ + struct w1_uart_device *w1dev = serdev_device_get_drvdata(serdev); + + mutex_lock(&w1dev->rx_mutex); + + /* sent a single byte and receive one single byte */ + if (count == 1) { + w1dev->rx_byte = buf[0]; + w1dev->rx_err = 0; + } else { + w1dev->rx_err = -EIO; + } + + mutex_unlock(&w1dev->rx_mutex); + complete(&w1dev->rx_byte_received); + + return count; +} + +static const struct serdev_device_ops w1_uart_serdev_ops = { + .receive_buf = w1_uart_serdev_receive_buf, + .write_wakeup = serdev_device_write_wakeup, +}; + +/* + * 1-wire reset and presence detect: A present slave will manipulate + * the received byte by pulling the 1-Wire low. + */ +static u8 w1_uart_reset_bus(void *data) +{ + struct w1_uart_device *w1dev = data; + const struct w1_uart_config *w1cfg = &w1dev->cfg_reset; + int ret; + u8 val; + + ret = w1_uart_serdev_tx_rx(w1dev, w1cfg, &val); + if (ret < 0) + return -1; + + /* Device present (0) or no device (1) */ + return val != w1cfg->tx_byte ? 0 : 1; +} + +/* + * 1-Wire read and write cycle: Only the read-0 manipulates the + * received byte, all others left the line untouched. + */ +static u8 w1_uart_touch_bit(void *data, u8 bit) +{ + struct w1_uart_device *w1dev = data; + const struct w1_uart_config *w1cfg = bit ? &w1dev->cfg_touch_1 : + &w1dev->cfg_touch_0; + int ret; + u8 val; + + ret = w1_uart_serdev_tx_rx(w1dev, w1cfg, &val); + + /* return inactive bus state on error */ + if (ret < 0) + return 1; + + return val == w1cfg->tx_byte ? 1 : 0; +} + +static int w1_uart_probe(struct serdev_device *serdev) +{ + struct device *dev = &serdev->dev; + struct w1_uart_device *w1dev; + int ret; + + w1dev = devm_kzalloc(dev, sizeof(*w1dev), GFP_KERNEL); + if (!w1dev) + return -ENOMEM; + w1dev->bus.data = w1dev; + w1dev->bus.reset_bus = w1_uart_reset_bus; + w1dev->bus.touch_bit = w1_uart_touch_bit; + w1dev->serdev = serdev; + + init_completion(&w1dev->rx_byte_received); + mutex_init(&w1dev->rx_mutex); + + ret = w1_uart_serdev_open(w1dev); + if (ret < 0) + return ret; + serdev_device_set_drvdata(serdev, w1dev); + serdev_device_set_client_ops(serdev, &w1_uart_serdev_ops); + + return w1_add_master_device(&w1dev->bus); +} + +static void w1_uart_remove(struct serdev_device *serdev) +{ + struct w1_uart_device *w1dev = serdev_device_get_drvdata(serdev); + + /* + * Waits until w1-uart callbacks are finished, serdev is closed + * and its device data released automatically by devres (waits + * until serdev-receive is finished). + */ + w1_remove_master_device(&w1dev->bus); +} + +static const struct of_device_id w1_uart_of_match[] = { + { .compatible = "w1-uart" }, + {}, +}; +MODULE_DEVICE_TABLE(of, w1_uart_of_match); + +static struct serdev_device_driver w1_uart_driver = { + .driver = { + .name = "w1-uart", + .of_match_table = w1_uart_of_match, + }, + .probe = w1_uart_probe, + .remove = w1_uart_remove, +}; + +module_serdev_device_driver(w1_uart_driver); + +MODULE_DESCRIPTION("UART w1 bus driver"); +MODULE_AUTHOR("Christoph Winklhofer "); +MODULE_LICENSE("GPL"); From 63724bbfb1e6b5e202f9393da4b25d4e7a46f5ec Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Mon, 19 Feb 2024 21:28:35 +0100 Subject: [PATCH 5/8] w1: mxc_w1: Convert to platform remove callback returning void MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is ignored (apart from emitting a warning) and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new(), which already returns void. Eventually after all drivers are converted, .remove_new() will be renamed to .remove(). Trivially convert this driver from always returning zero in the remove callback to the void returning variant. Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/d805f3ccc5bc59584c2575b7b33a56a33f6812c7.1708340114.git.u.kleine-koenig@pengutronix.de Signed-off-by: Krzysztof Kozlowski --- drivers/w1/masters/mxc_w1.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/w1/masters/mxc_w1.c b/drivers/w1/masters/mxc_w1.c index 090cbbf9e1e2..ba1d0866d1c4 100644 --- a/drivers/w1/masters/mxc_w1.c +++ b/drivers/w1/masters/mxc_w1.c @@ -151,15 +151,13 @@ static int mxc_w1_probe(struct platform_device *pdev) /* * disassociate the w1 device from the driver */ -static int mxc_w1_remove(struct platform_device *pdev) +static void mxc_w1_remove(struct platform_device *pdev) { struct mxc_w1_device *mdev = platform_get_drvdata(pdev); w1_remove_master_device(&mdev->bus_master); clk_disable_unprepare(mdev->clk); - - return 0; } static const struct of_device_id mxc_w1_dt_ids[] = { @@ -174,7 +172,7 @@ static struct platform_driver mxc_w1_driver = { .of_match_table = mxc_w1_dt_ids, }, .probe = mxc_w1_probe, - .remove = mxc_w1_remove, + .remove_new = mxc_w1_remove, }; module_platform_driver(mxc_w1_driver); From aa68465cf3d39996b291fb2080946c2e4d7cc100 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Mon, 19 Feb 2024 11:59:28 +0100 Subject: [PATCH 6/8] w1: omap_hdq: Convert to platform remove callback returning void MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is ignored (apart from emitting a warning) and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new(), which already returns void. Eventually after all drivers are converted, .remove_new() will be renamed to .remove(). Trivially convert this driver from always returning zero in the remove callback to the void returning variant. Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/f3a7eaee59020bf879249304eaaf9839c7e17222.1708340114.git.u.kleine-koenig@pengutronix.de Signed-off-by: Krzysztof Kozlowski --- drivers/w1/masters/omap_hdq.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/w1/masters/omap_hdq.c b/drivers/w1/masters/omap_hdq.c index 6a39b71eb718..d1cb5190445a 100644 --- a/drivers/w1/masters/omap_hdq.c +++ b/drivers/w1/masters/omap_hdq.c @@ -647,7 +647,7 @@ static int omap_hdq_probe(struct platform_device *pdev) return ret; } -static int omap_hdq_remove(struct platform_device *pdev) +static void omap_hdq_remove(struct platform_device *pdev) { int active; @@ -661,8 +661,6 @@ static int omap_hdq_remove(struct platform_device *pdev) if (active >= 0) pm_runtime_put_sync(&pdev->dev); pm_runtime_disable(&pdev->dev); - - return 0; } static const struct of_device_id omap_hdq_dt_ids[] = { @@ -674,7 +672,7 @@ MODULE_DEVICE_TABLE(of, omap_hdq_dt_ids); static struct platform_driver omap_hdq_driver = { .probe = omap_hdq_probe, - .remove = omap_hdq_remove, + .remove_new = omap_hdq_remove, .driver = { .name = "omap_hdq", .of_match_table = omap_hdq_dt_ids, From d7516044f167b219dae13010e6ff790e3fc96ef5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Mon, 19 Feb 2024 21:28:36 +0100 Subject: [PATCH 7/8] w1: sgi_w1: Convert to platform remove callback returning void MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is ignored (apart from emitting a warning) and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new(), which already returns void. Eventually after all drivers are converted, .remove_new() will be renamed to .remove(). Trivially convert this driver from always returning zero in the remove callback to the void returning variant. Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/68632fffa01f69eeaddfc0ad9de8f067b164e4fb.1708340114.git.u.kleine-koenig@pengutronix.de Signed-off-by: Krzysztof Kozlowski --- drivers/w1/masters/sgi_w1.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/w1/masters/sgi_w1.c b/drivers/w1/masters/sgi_w1.c index d7fbc3c146e1..7bb7876aa70e 100644 --- a/drivers/w1/masters/sgi_w1.c +++ b/drivers/w1/masters/sgi_w1.c @@ -105,13 +105,11 @@ static int sgi_w1_probe(struct platform_device *pdev) /* * disassociate the w1 device from the driver */ -static int sgi_w1_remove(struct platform_device *pdev) +static void sgi_w1_remove(struct platform_device *pdev) { struct sgi_w1_device *sdev = platform_get_drvdata(pdev); w1_remove_master_device(&sdev->bus_master); - - return 0; } static struct platform_driver sgi_w1_driver = { @@ -119,7 +117,7 @@ static struct platform_driver sgi_w1_driver = { .name = "sgi_w1", }, .probe = sgi_w1_probe, - .remove = sgi_w1_remove, + .remove_new = sgi_w1_remove, }; module_platform_driver(sgi_w1_driver); From d97d263132a69a0bda54efce3df04e55fa6341f7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Mon, 19 Feb 2024 11:59:30 +0100 Subject: [PATCH 8/8] w1: w1-gpio: Convert to platform remove callback returning void MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is ignored (apart from emitting a warning) and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new(), which already returns void. Eventually after all drivers are converted, .remove_new() will be renamed to .remove(). Trivially convert this driver from always returning zero in the remove callback to the void returning variant. Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/bd69ccde7395cf4bf63765e29c1ce83834d3669b.1708340114.git.u.kleine-koenig@pengutronix.de Signed-off-by: Krzysztof Kozlowski --- drivers/w1/masters/w1-gpio.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c index 05c67038ed20..34128e6bbbfa 100644 --- a/drivers/w1/masters/w1-gpio.c +++ b/drivers/w1/masters/w1-gpio.c @@ -141,7 +141,7 @@ static int w1_gpio_probe(struct platform_device *pdev) return 0; } -static int w1_gpio_remove(struct platform_device *pdev) +static void w1_gpio_remove(struct platform_device *pdev) { struct w1_bus_master *master = platform_get_drvdata(pdev); struct w1_gpio_ddata *ddata = master->data; @@ -150,8 +150,6 @@ static int w1_gpio_remove(struct platform_device *pdev) gpiod_set_value(ddata->pullup_gpiod, 0); w1_remove_master_device(master); - - return 0; } static struct platform_driver w1_gpio_driver = { @@ -160,7 +158,7 @@ static struct platform_driver w1_gpio_driver = { .of_match_table = of_match_ptr(w1_gpio_dt_ids), }, .probe = w1_gpio_probe, - .remove = w1_gpio_remove, + .remove_new = w1_gpio_remove, }; module_platform_driver(w1_gpio_driver);