mirror of
https://github.com/torvalds/linux.git
synced 2024-11-21 19:46:16 +00:00
d7516044f1
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 <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/68632fffa01f69eeaddfc0ad9de8f067b164e4fb.1708340114.git.u.kleine-koenig@pengutronix.de Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
127 lines
2.7 KiB
C
127 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* sgi_w1.c - w1 master driver for one wire support in SGI ASICs
|
|
*/
|
|
|
|
#include <linux/clk.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/io.h>
|
|
#include <linux/jiffies.h>
|
|
#include <linux/module.h>
|
|
#include <linux/mod_devicetable.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/platform_data/sgi-w1.h>
|
|
|
|
#include <linux/w1.h>
|
|
|
|
#define MCR_RD_DATA BIT(0)
|
|
#define MCR_DONE BIT(1)
|
|
|
|
#define MCR_PACK(pulse, sample) (((pulse) << 10) | ((sample) << 2))
|
|
|
|
struct sgi_w1_device {
|
|
u32 __iomem *mcr;
|
|
struct w1_bus_master bus_master;
|
|
char dev_id[64];
|
|
};
|
|
|
|
static u8 sgi_w1_wait(u32 __iomem *mcr)
|
|
{
|
|
u32 mcr_val;
|
|
|
|
do {
|
|
mcr_val = readl(mcr);
|
|
} while (!(mcr_val & MCR_DONE));
|
|
|
|
return (mcr_val & MCR_RD_DATA) ? 1 : 0;
|
|
}
|
|
|
|
/*
|
|
* this is the low level routine to
|
|
* reset the device on the One Wire interface
|
|
* on the hardware
|
|
*/
|
|
static u8 sgi_w1_reset_bus(void *data)
|
|
{
|
|
struct sgi_w1_device *dev = data;
|
|
u8 ret;
|
|
|
|
writel(MCR_PACK(520, 65), dev->mcr);
|
|
ret = sgi_w1_wait(dev->mcr);
|
|
udelay(500); /* recovery time */
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* this is the low level routine to read/write a bit on the One Wire
|
|
* interface on the hardware. It does write 0 if parameter bit is set
|
|
* to 0, otherwise a write 1/read.
|
|
*/
|
|
static u8 sgi_w1_touch_bit(void *data, u8 bit)
|
|
{
|
|
struct sgi_w1_device *dev = data;
|
|
u8 ret;
|
|
|
|
if (bit)
|
|
writel(MCR_PACK(6, 13), dev->mcr);
|
|
else
|
|
writel(MCR_PACK(80, 30), dev->mcr);
|
|
|
|
ret = sgi_w1_wait(dev->mcr);
|
|
if (bit)
|
|
udelay(100); /* recovery */
|
|
return ret;
|
|
}
|
|
|
|
static int sgi_w1_probe(struct platform_device *pdev)
|
|
{
|
|
struct sgi_w1_device *sdev;
|
|
struct sgi_w1_platform_data *pdata;
|
|
|
|
sdev = devm_kzalloc(&pdev->dev, sizeof(struct sgi_w1_device),
|
|
GFP_KERNEL);
|
|
if (!sdev)
|
|
return -ENOMEM;
|
|
|
|
sdev->mcr = devm_platform_ioremap_resource(pdev, 0);
|
|
if (IS_ERR(sdev->mcr))
|
|
return PTR_ERR(sdev->mcr);
|
|
|
|
sdev->bus_master.data = sdev;
|
|
sdev->bus_master.reset_bus = sgi_w1_reset_bus;
|
|
sdev->bus_master.touch_bit = sgi_w1_touch_bit;
|
|
|
|
pdata = dev_get_platdata(&pdev->dev);
|
|
if (pdata) {
|
|
strscpy(sdev->dev_id, pdata->dev_id, sizeof(sdev->dev_id));
|
|
sdev->bus_master.dev_id = sdev->dev_id;
|
|
}
|
|
|
|
platform_set_drvdata(pdev, sdev);
|
|
|
|
return w1_add_master_device(&sdev->bus_master);
|
|
}
|
|
|
|
/*
|
|
* disassociate the w1 device from the driver
|
|
*/
|
|
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);
|
|
}
|
|
|
|
static struct platform_driver sgi_w1_driver = {
|
|
.driver = {
|
|
.name = "sgi_w1",
|
|
},
|
|
.probe = sgi_w1_probe,
|
|
.remove_new = sgi_w1_remove,
|
|
};
|
|
module_platform_driver(sgi_w1_driver);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Thomas Bogendoerfer");
|
|
MODULE_DESCRIPTION("Driver for One-Wire IP in SGI ASICs");
|