mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-29 05:44:11 +00:00
1-Wire bus drivers for v6.9
1. Few cleanups: constifying, convert platform remove callback returning
void.
2. Add UART 1-Wire bus driver which uses UART interface to create the
1-Wire timing patterns.
-----BEGIN PGP SIGNATURE-----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=QRbM
-----END PGP SIGNATURE-----
Merge tag 'w1-drv-6.9' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux-w1 into tty-next
Krzysztof writes:
1-Wire bus drivers for v6.9
1. Few cleanups: constifying, convert platform remove callback returning
void.
2. Add UART 1-Wire bus driver which uses UART interface to create the
1-Wire timing patterns.
* tag 'w1-drv-6.9' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux-w1:
w1: w1-gpio: Convert to platform remove callback returning void
w1: sgi_w1: Convert to platform remove callback returning void
w1: omap_hdq: Convert to platform remove callback returning void
w1: mxc_w1: Convert to platform remove callback returning void
w1: add UART w1 bus driver
dt-bindings: w1: UART 1-Wire bus
dt-bindings: serial: allow onewire as child node
w1: make w1_bus_type const
This commit is contained in:
Greg Kroah-Hartman
commit
044591a6ad
12 changed files with 550 additions and 18 deletions
|
|
@ -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:
|
||||
|
|
|
|||
59
Documentation/devicetree/bindings/w1/w1-uart.yaml
Normal file
59
Documentation/devicetree/bindings/w1/w1-uart.yaml
Normal file
|
|
@ -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 <cj.winklhofer@gmail.com>
|
||||
|
||||
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";
|
||||
};
|
||||
};
|
||||
|
|
@ -12,3 +12,4 @@
|
|||
mxc-w1
|
||||
omap-hdq
|
||||
w1-gpio
|
||||
w1-uart
|
||||
|
|
|
|||
54
Documentation/w1/masters/w1-uart.rst
Normal file
54
Documentation/w1/masters/w1-uart.rst
Normal file
|
|
@ -0,0 +1,54 @@
|
|||
.. SPDX-License-Identifier: GPL-2.0-or-later
|
||||
|
||||
=====================
|
||||
Kernel driver w1-uart
|
||||
=====================
|
||||
|
||||
Author: Christoph Winklhofer <cj.winklhofer@gmail.com>
|
||||
|
||||
|
||||
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";
|
||||
};
|
||||
};
|
||||
|
|
@ -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
|
||||
|
||||
|
|
|
|||
|
|
@ -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
|
||||
|
|
|
|||
|
|
@ -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);
|
||||
|
||||
|
|
|
|||
|
|
@ -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,
|
||||
|
|
|
|||
|
|
@ -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);
|
||||
|
||||
|
|
|
|||
|
|
@ -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);
|
||||
|
|
|
|||
415
drivers/w1/masters/w1-uart.c
Normal file
415
drivers/w1/masters/w1-uart.c
Normal file
|
|
@ -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 <cj.winklhofer@gmail.com>
|
||||
*/
|
||||
|
||||
#include <linux/completion.h>
|
||||
#include <linux/delay.h>
|
||||
#include <linux/jiffies.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/mutex.h>
|
||||
#include <linux/of.h>
|
||||
#include <linux/serdev.h>
|
||||
#include <linux/w1.h>
|
||||
|
||||
/* 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 <cj.winklhofer@gmail.com>");
|
||||
MODULE_LICENSE("GPL");
|
||||
|
|
@ -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,
|
||||
};
|
||||
|
|
|
|||
Loading…
Reference in a new issue