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linux/drivers/rtc/rtc-mpfs.c
Christophe JAILLET 24fb316155 rtc: mpfs: Use devm_clk_get_enabled() helper 
The devm_clk_get_enabled() helper:
   - calls devm_clk_get()
   - calls clk_prepare_enable() and registers what is needed in order to
     call clk_disable_unprepare() when needed, as a managed resource.

This simplifies the code, the error handling paths and avoid the need of
a dedicated function used with devm_add_action_or_reset().

That said, mpfs_rtc_init_clk() is the same as devm_clk_get_enabled(), so
use this function directly instead.

This also fixes an (unlikely) unchecked devm_add_action_or_reset() error.

Based on my test with allyesconfig, this reduces the .o size from:
   text	   data	    bss	    dec	    hex	filename
   5330	   2208	      0	   7538	   1d72	drivers/rtc/rtc-mpfs.o
down to:
   5074	   2208	      0	   7282	   1c72	drivers/rtc/rtc-mpfs.o

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/e55c959f2821a2c367a4c5de529a638b1cc6b8cd.1661329086.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2022-10-13 00:31:18 +02:00

306 lines
8.0 KiB
C
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// SPDX-License-Identifier: GPL-2.0
/*
* Microchip MPFS RTC driver
*
* Copyright (c) 2021-2022 Microchip Corporation. All rights reserved.
*
* Author: Daire McNamara <daire.mcnamara@microchip.com>
* & Conor Dooley <conor.dooley@microchip.com>
*/
#include "linux/bits.h"
#include "linux/iopoll.h"
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_wakeirq.h>
#include <linux/slab.h>
#include <linux/rtc.h>
#define CONTROL_REG 0x00
#define MODE_REG 0x04
#define PRESCALER_REG 0x08
#define ALARM_LOWER_REG 0x0c
#define ALARM_UPPER_REG 0x10
#define COMPARE_LOWER_REG 0x14
#define COMPARE_UPPER_REG 0x18
#define DATETIME_LOWER_REG 0x20
#define DATETIME_UPPER_REG 0x24
#define CONTROL_RUNNING_BIT BIT(0)
#define CONTROL_START_BIT BIT(0)
#define CONTROL_STOP_BIT BIT(1)
#define CONTROL_ALARM_ON_BIT BIT(2)
#define CONTROL_ALARM_OFF_BIT BIT(3)
#define CONTROL_RESET_BIT BIT(4)
#define CONTROL_UPLOAD_BIT BIT(5)
#define CONTROL_DOWNLOAD_BIT BIT(6)
#define CONTROL_MATCH_BIT BIT(7)
#define CONTROL_WAKEUP_CLR_BIT BIT(8)
#define CONTROL_WAKEUP_SET_BIT BIT(9)
#define CONTROL_UPDATED_BIT BIT(10)
#define MODE_CLOCK_CALENDAR BIT(0)
#define MODE_WAKE_EN BIT(1)
#define MODE_WAKE_RESET BIT(2)
#define MODE_WAKE_CONTINUE BIT(3)
#define MAX_PRESCALER_COUNT GENMASK(25, 0)
#define DATETIME_UPPER_MASK GENMASK(29, 0)
#define ALARM_UPPER_MASK GENMASK(10, 0)
#define UPLOAD_TIMEOUT_US 50
struct mpfs_rtc_dev {
struct rtc_device *rtc;
void __iomem *base;
};
static void mpfs_rtc_start(struct mpfs_rtc_dev *rtcdev)
{
u32 ctrl;
ctrl = readl(rtcdev->base + CONTROL_REG);
ctrl &= ~CONTROL_STOP_BIT;
ctrl |= CONTROL_START_BIT;
writel(ctrl, rtcdev->base + CONTROL_REG);
}
static void mpfs_rtc_clear_irq(struct mpfs_rtc_dev *rtcdev)
{
u32 val = readl(rtcdev->base + CONTROL_REG);
val &= ~(CONTROL_ALARM_ON_BIT | CONTROL_STOP_BIT);
val |= CONTROL_ALARM_OFF_BIT;
writel(val, rtcdev->base + CONTROL_REG);
/*
* Ensure that the posted write to the CONTROL_REG register completed before
* returning from this function. Not doing this may result in the interrupt
* only being cleared some time after this function returns.
*/
(void)readl(rtcdev->base + CONTROL_REG);
}
static int mpfs_rtc_readtime(struct device *dev, struct rtc_time *tm)
{
struct mpfs_rtc_dev *rtcdev = dev_get_drvdata(dev);
u64 time;
time = readl(rtcdev->base + DATETIME_LOWER_REG);
time |= ((u64)readl(rtcdev->base + DATETIME_UPPER_REG) & DATETIME_UPPER_MASK) << 32;
rtc_time64_to_tm(time, tm);
return 0;
}
static int mpfs_rtc_settime(struct device *dev, struct rtc_time *tm)
{
struct mpfs_rtc_dev *rtcdev = dev_get_drvdata(dev);
u32 ctrl, prog;
u64 time;
int ret;
time = rtc_tm_to_time64(tm);
writel((u32)time, rtcdev->base + DATETIME_LOWER_REG);
writel((u32)(time >> 32) & DATETIME_UPPER_MASK, rtcdev->base + DATETIME_UPPER_REG);
ctrl = readl(rtcdev->base + CONTROL_REG);
ctrl &= ~CONTROL_STOP_BIT;
ctrl |= CONTROL_UPLOAD_BIT;
writel(ctrl, rtcdev->base + CONTROL_REG);
ret = read_poll_timeout(readl, prog, prog & CONTROL_UPLOAD_BIT, 0, UPLOAD_TIMEOUT_US,
false, rtcdev->base + CONTROL_REG);
if (ret) {
dev_err(dev, "timed out uploading time to rtc");
return ret;
}
mpfs_rtc_start(rtcdev);
return 0;
}
static int mpfs_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct mpfs_rtc_dev *rtcdev = dev_get_drvdata(dev);
u32 mode = readl(rtcdev->base + MODE_REG);
u64 time;
alrm->enabled = mode & MODE_WAKE_EN;
time = (u64)readl(rtcdev->base + ALARM_LOWER_REG) << 32;
time |= (readl(rtcdev->base + ALARM_UPPER_REG) & ALARM_UPPER_MASK);
rtc_time64_to_tm(time, &alrm->time);
return 0;
}
static int mpfs_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct mpfs_rtc_dev *rtcdev = dev_get_drvdata(dev);
u32 mode, ctrl;
u64 time;
/* Disable the alarm before updating */
ctrl = readl(rtcdev->base + CONTROL_REG);
ctrl |= CONTROL_ALARM_OFF_BIT;
writel(ctrl, rtcdev->base + CONTROL_REG);
time = rtc_tm_to_time64(&alrm->time);
writel((u32)time, rtcdev->base + ALARM_LOWER_REG);
writel((u32)(time >> 32) & ALARM_UPPER_MASK, rtcdev->base + ALARM_UPPER_REG);
/* Bypass compare register in alarm mode */
writel(GENMASK(31, 0), rtcdev->base + COMPARE_LOWER_REG);
writel(GENMASK(29, 0), rtcdev->base + COMPARE_UPPER_REG);
/* Configure the RTC to enable the alarm. */
ctrl = readl(rtcdev->base + CONTROL_REG);
mode = readl(rtcdev->base + MODE_REG);
if (alrm->enabled) {
mode = MODE_WAKE_EN | MODE_WAKE_CONTINUE;
/* Enable the alarm */
ctrl &= ~CONTROL_ALARM_OFF_BIT;
ctrl |= CONTROL_ALARM_ON_BIT;
}
ctrl &= ~CONTROL_STOP_BIT;
ctrl |= CONTROL_START_BIT;
writel(ctrl, rtcdev->base + CONTROL_REG);
writel(mode, rtcdev->base + MODE_REG);
return 0;
}
static int mpfs_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct mpfs_rtc_dev *rtcdev = dev_get_drvdata(dev);
u32 ctrl;
ctrl = readl(rtcdev->base + CONTROL_REG);
ctrl &= ~(CONTROL_ALARM_ON_BIT | CONTROL_ALARM_OFF_BIT | CONTROL_STOP_BIT);
if (enabled)
ctrl |= CONTROL_ALARM_ON_BIT;
else
ctrl |= CONTROL_ALARM_OFF_BIT;
writel(ctrl, rtcdev->base + CONTROL_REG);
return 0;
}
static irqreturn_t mpfs_rtc_wakeup_irq_handler(int irq, void *dev)
{
struct mpfs_rtc_dev *rtcdev = dev;
mpfs_rtc_clear_irq(rtcdev);
rtc_update_irq(rtcdev->rtc, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static const struct rtc_class_ops mpfs_rtc_ops = {
.read_time = mpfs_rtc_readtime,
.set_time = mpfs_rtc_settime,
.read_alarm = mpfs_rtc_readalarm,
.set_alarm = mpfs_rtc_setalarm,
.alarm_irq_enable = mpfs_rtc_alarm_irq_enable,
};
static int mpfs_rtc_probe(struct platform_device *pdev)
{
struct mpfs_rtc_dev *rtcdev;
struct clk *clk;
unsigned long prescaler;
int wakeup_irq, ret;
rtcdev = devm_kzalloc(&pdev->dev, sizeof(struct mpfs_rtc_dev), GFP_KERNEL);
if (!rtcdev)
return -ENOMEM;
platform_set_drvdata(pdev, rtcdev);
rtcdev->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtcdev->rtc))
return PTR_ERR(rtcdev->rtc);
rtcdev->rtc->ops = &mpfs_rtc_ops;
/* range is capped by alarm max, lower reg is 31:0 & upper is 10:0 */
rtcdev->rtc->range_max = GENMASK_ULL(42, 0);
clk = devm_clk_get_enabled(&pdev->dev, "rtc");
if (IS_ERR(clk))
return PTR_ERR(clk);
rtcdev->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(rtcdev->base)) {
dev_dbg(&pdev->dev, "invalid ioremap resources\n");
return PTR_ERR(rtcdev->base);
}
wakeup_irq = platform_get_irq(pdev, 0);
if (wakeup_irq <= 0) {
dev_dbg(&pdev->dev, "could not get wakeup irq\n");
return wakeup_irq;
}
ret = devm_request_irq(&pdev->dev, wakeup_irq, mpfs_rtc_wakeup_irq_handler, 0,
dev_name(&pdev->dev), rtcdev);
if (ret) {
dev_dbg(&pdev->dev, "could not request wakeup irq\n");
return ret;
}
/* prescaler hardware adds 1 to reg value */
prescaler = clk_get_rate(devm_clk_get(&pdev->dev, "rtcref")) - 1;
if (prescaler > MAX_PRESCALER_COUNT) {
dev_dbg(&pdev->dev, "invalid prescaler %lu\n", prescaler);
return -EINVAL;
}
writel(prescaler, rtcdev->base + PRESCALER_REG);
dev_info(&pdev->dev, "prescaler set to: %lu\n", prescaler);
device_init_wakeup(&pdev->dev, true);
ret = dev_pm_set_wake_irq(&pdev->dev, wakeup_irq);
if (ret)
dev_err(&pdev->dev, "failed to enable irq wake\n");
return devm_rtc_register_device(rtcdev->rtc);
}
static int mpfs_rtc_remove(struct platform_device *pdev)
{
dev_pm_clear_wake_irq(&pdev->dev);
return 0;
}
static const struct of_device_id mpfs_rtc_of_match[] = {
{ .compatible = "microchip,mpfs-rtc" },
{ }
};
MODULE_DEVICE_TABLE(of, mpfs_rtc_of_match);
static struct platform_driver mpfs_rtc_driver = {
.probe = mpfs_rtc_probe,
.remove = mpfs_rtc_remove,
.driver = {
.name = "mpfs_rtc",
.of_match_table = mpfs_rtc_of_match,
},
};
module_platform_driver(mpfs_rtc_driver);
MODULE_DESCRIPTION("Real time clock for Microchip Polarfire SoC");
MODULE_AUTHOR("Daire McNamara <daire.mcnamara@microchip.com>");
MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
MODULE_LICENSE("GPL");
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