[PATCH 4/5 v2] watchdog: ftwdt010: Add clock support
Linus Walleij
linus.walleij at linaro.org
Mon Oct 16 13:54:26 PDT 2017
The Gemini platform now provides a proper clock look-up for this
and other IPs, so add clock support to the driver. This also aids
in using the same driver with other platforms such as MOXA ART.
The IP has two clock inputs: PCLK (the IP peripheral clock) and
EXTCLK (an external clock). We are a bit elaborate around this:
on Gemini the EXTCLK is used by default today and it's 5MHz, and
on MOXA ART the PCLK is used. On Aspeed the EXTCLK is used and
it's 1MHz. So add some clever code to fall back to platform
defaults if PCLK or EXTCLK is not provided by the device tree.
Take this opportunity to implement .remove() for the driver that
stops the watchdog and disables the clocks.
Add credits that this code is inspired by MOXA ART.
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
ChangeLog v1->v2:
- Strictly require the clock framework
- Sort header files in alphabetic order
- Fix the error path to properly disable the clocks
- Fix spelling in commit message
- Be minimalist with informational messages and cut down
on error messages
---
drivers/watchdog/Kconfig | 1 +
drivers/watchdog/ftwdt010_wdt.c | 79 ++++++++++++++++++++++++++++++++++++-----
2 files changed, 71 insertions(+), 9 deletions(-)
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index fd44a542036a..245cff03c992 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -324,6 +324,7 @@ config 977_WATCHDOG
config FTWDT010_WATCHDOG
tristate "Faraday Technology FTWDT010 watchdog"
depends on ARM || COMPILE_TEST
+ depends on COMMON_CLK
select WATCHDOG_CORE
default ARCH_GEMINI
help
diff --git a/drivers/watchdog/ftwdt010_wdt.c b/drivers/watchdog/ftwdt010_wdt.c
index a9c2912ee280..21c3ac7f557a 100644
--- a/drivers/watchdog/ftwdt010_wdt.c
+++ b/drivers/watchdog/ftwdt010_wdt.c
@@ -5,6 +5,8 @@
*
* Inspired by the out-of-tree drivers from OpenWRT:
* Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas at teltonika.lt>
+ * Inspired by the MOXA ART driver from Jonas Jensen:
+ * Copyright (C) 2013 Jonas Jensen <jonas.jensen at gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@@ -12,12 +14,14 @@
*/
#include <linux/bitops.h>
+#include <linux/clk.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
+#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/watchdog.h>
@@ -29,19 +33,21 @@
#define WDRESTART_MAGIC 0x5AB9
-#define WDCR_CLOCK_5MHZ BIT(4)
+#define WDCR_EXTCLK BIT(4)
#define WDCR_WDEXT BIT(3)
#define WDCR_WDINTR BIT(2)
#define WDCR_SYS_RST BIT(1)
#define WDCR_ENABLE BIT(0)
-#define WDT_CLOCK 5000000 /* 5 MHz */
-
struct ftwdt010_wdt {
struct watchdog_device wdd;
struct device *dev;
void __iomem *base;
bool has_irq;
+ struct clk *pclk;
+ struct clk *extclk;
+ unsigned int clk_freq;
+ bool use_extclk;
};
static inline
@@ -55,10 +61,12 @@ static int ftwdt010_wdt_start(struct watchdog_device *wdd)
struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
u32 enable;
- writel(wdd->timeout * WDT_CLOCK, gwdt->base + FTWDT010_WDLOAD);
+ writel(wdd->timeout * gwdt->clk_freq, gwdt->base + FTWDT010_WDLOAD);
writel(WDRESTART_MAGIC, gwdt->base + FTWDT010_WDRESTART);
/* set clock before enabling */
- enable = WDCR_CLOCK_5MHZ | WDCR_SYS_RST;
+ enable = WDCR_SYS_RST;
+ if (gwdt->use_extclk)
+ enable |= WDCR_EXTCLK;
writel(enable, gwdt->base + FTWDT010_WDCR);
if (gwdt->has_irq)
enable |= WDCR_WDINTR;
@@ -124,6 +132,7 @@ static const struct watchdog_info ftwdt010_wdt_info = {
static int ftwdt010_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
struct resource *res;
struct ftwdt010_wdt *gwdt;
unsigned int reg;
@@ -139,11 +148,40 @@ static int ftwdt010_wdt_probe(struct platform_device *pdev)
if (IS_ERR(gwdt->base))
return PTR_ERR(gwdt->base);
+ gwdt->use_extclk = of_property_read_bool(np, "faraday,use-extclk");
+
+ gwdt->pclk = devm_clk_get(dev, "PCLK");
+ if (IS_ERR(gwdt->pclk))
+ return PTR_ERR(gwdt->pclk);
+ ret = clk_prepare_enable(gwdt->pclk);
+ if (ret)
+ return ret;
+ if (!gwdt->use_extclk)
+ gwdt->clk_freq = clk_get_rate(gwdt->pclk);
+
+ /* Only enable and get frequency from EXTCLK if it's in use */
+ if (gwdt->use_extclk) {
+ gwdt->extclk = devm_clk_get(dev, "EXTCLK");
+ if (IS_ERR(gwdt->extclk)) {
+ ret = PTR_ERR(gwdt->extclk);
+ goto out_disable_pclk;
+ }
+ ret = clk_prepare_enable(gwdt->extclk);
+ if (ret)
+ goto out_disable_pclk;
+ gwdt->clk_freq = clk_get_rate(gwdt->extclk);
+ }
+
+ if (gwdt->clk_freq == 0) {
+ ret = -EINVAL;
+ goto out_disable_extclk;
+ }
+
gwdt->dev = dev;
gwdt->wdd.info = &ftwdt010_wdt_info;
gwdt->wdd.ops = &ftwdt010_wdt_ops;
gwdt->wdd.min_timeout = 1;
- gwdt->wdd.max_timeout = 0xFFFFFFFF / WDT_CLOCK;
+ gwdt->wdd.max_timeout = UINT_MAX / gwdt->clk_freq;
gwdt->wdd.parent = dev;
/*
@@ -165,19 +203,41 @@ static int ftwdt010_wdt_probe(struct platform_device *pdev)
ret = devm_request_irq(dev, irq, ftwdt010_wdt_interrupt, 0,
"watchdog bark", gwdt);
if (ret)
- return ret;
+ goto out_disable_extclk;
gwdt->has_irq = true;
}
ret = devm_watchdog_register_device(dev, &gwdt->wdd);
if (ret) {
dev_err(&pdev->dev, "failed to register watchdog\n");
- return ret;
+ goto out_disable_extclk;
}
/* Set up platform driver data */
platform_set_drvdata(pdev, gwdt);
- dev_info(dev, "FTWDT010 watchdog driver enabled\n");
+ dev_info(dev, "FTWDT010 watchdog driver @%uHz\n",
+ gwdt->clk_freq);
+
+ return 0;
+
+out_disable_extclk:
+ if (gwdt->use_extclk)
+ clk_disable_unprepare(gwdt->extclk);
+out_disable_pclk:
+ if (!IS_ERR(gwdt->pclk))
+ clk_disable_unprepare(gwdt->pclk);
+
+ return ret;
+}
+
+static int ftwdt010_wdt_remove(struct platform_device *pdev)
+{
+ struct ftwdt010_wdt *gwdt = platform_get_drvdata(pdev);
+
+ writel(0, gwdt->base + FTWDT010_WDCR);
+ clk_disable_unprepare(gwdt->pclk);
+ if (gwdt->use_extclk)
+ clk_disable_unprepare(gwdt->extclk);
return 0;
}
@@ -224,6 +284,7 @@ MODULE_DEVICE_TABLE(of, ftwdt010_wdt_match);
static struct platform_driver ftwdt010_wdt_driver = {
.probe = ftwdt010_wdt_probe,
+ .remove = ftwdt010_wdt_remove,
.driver = {
.name = "ftwdt010-wdt",
.of_match_table = of_match_ptr(ftwdt010_wdt_match),
--
2.13.6
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