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linux/drivers/rtc/rtc-zynqmp.c
Uwe Kleine-König f45e5cfa73 rtc: zynqmp: Convert to platform remove callback returning void 
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 (mostly) ignored
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.

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/20230304133028.2135435-42-u.kleine-koenig@pengutronix.de
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2023-03-17 23:03:19 +01:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Xilinx Zynq Ultrascale+ MPSoC Real Time Clock Driver
*
* Copyright (C) 2015 Xilinx, Inc.
*
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
/* RTC Registers */
#define RTC_SET_TM_WR 0x00
#define RTC_SET_TM_RD 0x04
#define RTC_CALIB_WR 0x08
#define RTC_CALIB_RD 0x0C
#define RTC_CUR_TM 0x10
#define RTC_CUR_TICK 0x14
#define RTC_ALRM 0x18
#define RTC_INT_STS 0x20
#define RTC_INT_MASK 0x24
#define RTC_INT_EN 0x28
#define RTC_INT_DIS 0x2C
#define RTC_CTRL 0x40
#define RTC_FR_EN BIT(20)
#define RTC_FR_DATSHIFT 16
#define RTC_TICK_MASK 0xFFFF
#define RTC_INT_SEC BIT(0)
#define RTC_INT_ALRM BIT(1)
#define RTC_OSC_EN BIT(24)
#define RTC_BATT_EN BIT(31)
#define RTC_CALIB_DEF 0x7FFF
#define RTC_CALIB_MASK 0x1FFFFF
#define RTC_ALRM_MASK BIT(1)
#define RTC_MSEC 1000
#define RTC_FR_MASK 0xF0000
#define RTC_FR_MAX_TICKS 16
#define RTC_PPB 1000000000LL
#define RTC_MIN_OFFSET -32768000
#define RTC_MAX_OFFSET 32767000
struct xlnx_rtc_dev {
struct rtc_device *rtc;
void __iomem *reg_base;
int alarm_irq;
int sec_irq;
struct clk *rtc_clk;
unsigned int freq;
};
static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
unsigned long new_time;
/*
* The value written will be updated after 1 sec into the
* seconds read register, so we need to program time +1 sec
* to get the correct time on read.
*/
new_time = rtc_tm_to_time64(tm) + 1;
writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR);
/*
* Clear the rtc interrupt status register after setting the
* time. During a read_time function, the code should read the
* RTC_INT_STATUS register and if bit 0 is still 0, it means
* that one second has not elapsed yet since RTC was set and
* the current time should be read from SET_TIME_READ register;
* otherwise, CURRENT_TIME register is read to report the time
*/
writel(RTC_INT_SEC, xrtcdev->reg_base + RTC_INT_STS);
return 0;
}
static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
u32 status;
unsigned long read_time;
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
status = readl(xrtcdev->reg_base + RTC_INT_STS);
if (status & RTC_INT_SEC) {
/*
* RTC has updated the CURRENT_TIME with the time written into
* SET_TIME_WRITE register.
*/
read_time = readl(xrtcdev->reg_base + RTC_CUR_TM);
} else {
/*
* Time written in SET_TIME_WRITE has not yet updated into
* the seconds read register, so read the time from the
* SET_TIME_WRITE instead of CURRENT_TIME register.
* Since we add +1 sec while writing, we need to -1 sec while
* reading.
*/
read_time = readl(xrtcdev->reg_base + RTC_SET_TM_RD) - 1;
}
rtc_time64_to_tm(read_time, tm);
return 0;
}
static int xlnx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_ALRM), &alrm->time);
alrm->enabled = readl(xrtcdev->reg_base + RTC_INT_MASK) & RTC_INT_ALRM;
return 0;
}
static int xlnx_rtc_alarm_irq_enable(struct device *dev, u32 enabled)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
unsigned int status;
ulong timeout;
timeout = jiffies + msecs_to_jiffies(RTC_MSEC);
if (enabled) {
while (1) {
status = readl(xrtcdev->reg_base + RTC_INT_STS);
if (!((status & RTC_ALRM_MASK) == RTC_ALRM_MASK))
break;
if (time_after_eq(jiffies, timeout)) {
dev_err(dev, "Time out occur, while clearing alarm status bit\n");
return -ETIMEDOUT;
}
writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_STS);
}
writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_EN);
} else {
writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS);
}
return 0;
}
static int xlnx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
unsigned long alarm_time;
alarm_time = rtc_tm_to_time64(&alrm->time);
writel((u32)alarm_time, (xrtcdev->reg_base + RTC_ALRM));
xlnx_rtc_alarm_irq_enable(dev, alrm->enabled);
return 0;
}
static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev)
{
u32 rtc_ctrl;
/* Enable RTC switch to battery when VCC_PSAUX is not available */
rtc_ctrl = readl(xrtcdev->reg_base + RTC_CTRL);
rtc_ctrl |= RTC_BATT_EN;
writel(rtc_ctrl, xrtcdev->reg_base + RTC_CTRL);
}
static int xlnx_rtc_read_offset(struct device *dev, long *offset)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
unsigned long long rtc_ppb = RTC_PPB;
unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq);
unsigned int calibval;
long offset_val;
calibval = readl(xrtcdev->reg_base + RTC_CALIB_RD);
/* Offset with seconds ticks */
offset_val = calibval & RTC_TICK_MASK;
offset_val = offset_val - RTC_CALIB_DEF;
offset_val = offset_val * tick_mult;
/* Offset with fractional ticks */
if (calibval & RTC_FR_EN)
offset_val += ((calibval & RTC_FR_MASK) >> RTC_FR_DATSHIFT)
* (tick_mult / RTC_FR_MAX_TICKS);
*offset = offset_val;
return 0;
}
static int xlnx_rtc_set_offset(struct device *dev, long offset)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
unsigned long long rtc_ppb = RTC_PPB;
unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq);
unsigned char fract_tick = 0;
unsigned int calibval;
short int max_tick;
int fract_offset;
if (offset < RTC_MIN_OFFSET || offset > RTC_MAX_OFFSET)
return -ERANGE;
/* Number ticks for given offset */
max_tick = div_s64_rem(offset, tick_mult, &fract_offset);
/* Number fractional ticks for given offset */
if (fract_offset) {
if (fract_offset < 0) {
fract_offset = fract_offset + tick_mult;
max_tick--;
}
if (fract_offset > (tick_mult / RTC_FR_MAX_TICKS)) {
for (fract_tick = 1; fract_tick < 16; fract_tick++) {
if (fract_offset <=
(fract_tick *
(tick_mult / RTC_FR_MAX_TICKS)))
break;
}
}
}
/* Zynqmp RTC uses second and fractional tick
* counters for compensation
*/
calibval = max_tick + RTC_CALIB_DEF;
if (fract_tick)
calibval |= RTC_FR_EN;
calibval |= (fract_tick << RTC_FR_DATSHIFT);
writel(calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
return 0;
}
static const struct rtc_class_ops xlnx_rtc_ops = {
.set_time = xlnx_rtc_set_time,
.read_time = xlnx_rtc_read_time,
.read_alarm = xlnx_rtc_read_alarm,
.set_alarm = xlnx_rtc_set_alarm,
.alarm_irq_enable = xlnx_rtc_alarm_irq_enable,
.read_offset = xlnx_rtc_read_offset,
.set_offset = xlnx_rtc_set_offset,
};
static irqreturn_t xlnx_rtc_interrupt(int irq, void *id)
{
struct xlnx_rtc_dev *xrtcdev = (struct xlnx_rtc_dev *)id;
unsigned int status;
status = readl(xrtcdev->reg_base + RTC_INT_STS);
/* Check if interrupt asserted */
if (!(status & (RTC_INT_SEC | RTC_INT_ALRM)))
return IRQ_NONE;
/* Disable RTC_INT_ALRM interrupt only */
writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS);
if (status & RTC_INT_ALRM)
rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static int xlnx_rtc_probe(struct platform_device *pdev)
{
struct xlnx_rtc_dev *xrtcdev;
int ret;
xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL);
if (!xrtcdev)
return -ENOMEM;
platform_set_drvdata(pdev, xrtcdev);
xrtcdev->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(xrtcdev->rtc))
return PTR_ERR(xrtcdev->rtc);
xrtcdev->rtc->ops = &xlnx_rtc_ops;
xrtcdev->rtc->range_max = U32_MAX;
xrtcdev->reg_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(xrtcdev->reg_base))
return PTR_ERR(xrtcdev->reg_base);
xrtcdev->alarm_irq = platform_get_irq_byname(pdev, "alarm");
if (xrtcdev->alarm_irq < 0)
return xrtcdev->alarm_irq;
ret = devm_request_irq(&pdev->dev, xrtcdev->alarm_irq,
xlnx_rtc_interrupt, 0,
dev_name(&pdev->dev), xrtcdev);
if (ret) {
dev_err(&pdev->dev, "request irq failed\n");
return ret;
}
xrtcdev->sec_irq = platform_get_irq_byname(pdev, "sec");
if (xrtcdev->sec_irq < 0)
return xrtcdev->sec_irq;
ret = devm_request_irq(&pdev->dev, xrtcdev->sec_irq,
xlnx_rtc_interrupt, 0,
dev_name(&pdev->dev), xrtcdev);
if (ret) {
dev_err(&pdev->dev, "request irq failed\n");
return ret;
}
/* Getting the rtc_clk info */
xrtcdev->rtc_clk = devm_clk_get_optional(&pdev->dev, "rtc_clk");
if (IS_ERR(xrtcdev->rtc_clk)) {
if (PTR_ERR(xrtcdev->rtc_clk) != -EPROBE_DEFER)
dev_warn(&pdev->dev, "Device clock not found.\n");
}
xrtcdev->freq = clk_get_rate(xrtcdev->rtc_clk);
if (!xrtcdev->freq) {
ret = of_property_read_u32(pdev->dev.of_node, "calibration",
&xrtcdev->freq);
if (ret)
xrtcdev->freq = RTC_CALIB_DEF;
}
ret = readl(xrtcdev->reg_base + RTC_CALIB_RD);
if (!ret)
writel(xrtcdev->freq, (xrtcdev->reg_base + RTC_CALIB_WR));
xlnx_init_rtc(xrtcdev);
device_init_wakeup(&pdev->dev, 1);
return devm_rtc_register_device(xrtcdev->rtc);
}
static void xlnx_rtc_remove(struct platform_device *pdev)
{
xlnx_rtc_alarm_irq_enable(&pdev->dev, 0);
device_init_wakeup(&pdev->dev, 0);
}
static int __maybe_unused xlnx_rtc_suspend(struct device *dev)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
enable_irq_wake(xrtcdev->alarm_irq);
else
xlnx_rtc_alarm_irq_enable(dev, 0);
return 0;
}
static int __maybe_unused xlnx_rtc_resume(struct device *dev)
{
struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
disable_irq_wake(xrtcdev->alarm_irq);
else
xlnx_rtc_alarm_irq_enable(dev, 1);
return 0;
}
static SIMPLE_DEV_PM_OPS(xlnx_rtc_pm_ops, xlnx_rtc_suspend, xlnx_rtc_resume);
static const struct of_device_id xlnx_rtc_of_match[] = {
{.compatible = "xlnx,zynqmp-rtc" },
{ }
};
MODULE_DEVICE_TABLE(of, xlnx_rtc_of_match);
static struct platform_driver xlnx_rtc_driver = {
.probe = xlnx_rtc_probe,
.remove_new = xlnx_rtc_remove,
.driver = {
.name = KBUILD_MODNAME,
.pm = &xlnx_rtc_pm_ops,
.of_match_table = xlnx_rtc_of_match,
},
};
module_platform_driver(xlnx_rtc_driver);
MODULE_DESCRIPTION("Xilinx Zynq MPSoC RTC driver");
MODULE_AUTHOR("Xilinx Inc.");
MODULE_LICENSE("GPL v2");
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