Re: [PATCH V4 2/4] watchdog: stm32: add pclk feature for stm32mp1

From: Ludovic BARRE
Date: Fri Jun 22 2018 - 05:16:07 EST



On 06/21/2018 06:53 PM, Guenter Roeck wrote:
On Thu, Jun 21, 2018 at 11:02:15AM +0200, Ludovic Barre wrote:
From: Ludovic Barre <ludovic.barre@xxxxxx>

This patch adds compatible data to manage pclk clock by
compatible. Adds stm32mp1 support which requires pclk clock.

Signed-off-by: Ludovic Barre <ludovic.barre@xxxxxx>
---
drivers/watchdog/stm32_iwdg.c | 116 +++++++++++++++++++++++++++---------------
1 file changed, 74 insertions(+), 42 deletions(-)

diff --git a/drivers/watchdog/stm32_iwdg.c b/drivers/watchdog/stm32_iwdg.c
index c97ad56..e00e3b3 100644
--- a/drivers/watchdog/stm32_iwdg.c
+++ b/drivers/watchdog/stm32_iwdg.c
@@ -11,12 +11,13 @@
#include <linux/clk.h>
#include <linux/delay.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
#include <linux/of.h>
+#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
@@ -54,11 +55,15 @@
#define TIMEOUT_US 100000
#define SLEEP_US 1000
+#define HAS_PCLK true
+
struct stm32_iwdg {
struct watchdog_device wdd;
void __iomem *regs;
- struct clk *clk;
+ struct clk *clk_lsi;
+ struct clk *clk_pclk;
unsigned int rate;
+ bool has_pclk;
};
static inline u32 reg_read(void __iomem *base, u32 reg)
@@ -133,6 +138,44 @@ static int stm32_iwdg_set_timeout(struct watchdog_device *wdd,
return 0;
}
+static int stm32_iwdg_clk_init(struct platform_device *pdev,
+ struct stm32_iwdg *wdt)
+{
+ u32 ret;
+
+ wdt->clk_lsi = devm_clk_get(&pdev->dev, "lsi");

I just noticed a subtle difference: This used to be
devm_clk_get(&pdev->dev, NULL);
which would always get the first clock, no matter how it is named.
Can that cause problems with backward compatibility ?

You are right Guenter.

When there are multiple clocks, I prefer to use name interface.
I find it easier to use, and avoid misunderstanding.

Today, only one "dtsi" define the watchdog and it's disabled
(stm32f429.dtsi). I think it's good moment to move to clock named
(before it is used anymore).

But you are right I forgot to change stm32f429.dtsi.
If I add a commit for stm32f429.dtsi, it's Ok for you ?

BR
Ludo


Thanks,
Guenter

+ if (IS_ERR(wdt->clk_lsi)) {
+ dev_err(&pdev->dev, "Unable to get lsi clock\n");
+ return PTR_ERR(wdt->clk_lsi);
+ }
+
+ /* optional peripheral clock */
+ if (wdt->has_pclk) {
+ wdt->clk_pclk = devm_clk_get(&pdev->dev, "pclk");
+ if (IS_ERR(wdt->clk_pclk)) {
+ dev_err(&pdev->dev, "Unable to get pclk clock\n");
+ return PTR_ERR(wdt->clk_pclk);
+ }
+
+ ret = clk_prepare_enable(wdt->clk_pclk);
+ if (ret) {
+ dev_err(&pdev->dev, "Unable to prepare pclk clock\n");
+ return ret;
+ }
+ }
+
+ ret = clk_prepare_enable(wdt->clk_lsi);
+ if (ret) {
+ dev_err(&pdev->dev, "Unable to prepare lsi clock\n");
+ clk_disable_unprepare(wdt->clk_pclk);
+ return ret;
+ }
+
+ wdt->rate = clk_get_rate(wdt->clk_lsi);
+
+ return 0;
+}
+
static const struct watchdog_info stm32_iwdg_info = {
.options = WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE |
@@ -147,49 +190,42 @@ static const struct watchdog_ops stm32_iwdg_ops = {
.set_timeout = stm32_iwdg_set_timeout,
};
+static const struct of_device_id stm32_iwdg_of_match[] = {
+ { .compatible = "st,stm32-iwdg", .data = (void *)!HAS_PCLK },
+ { .compatible = "st,stm32mp1-iwdg", .data = (void *)HAS_PCLK },
+ { /* end node */ }
+};
+MODULE_DEVICE_TABLE(of, stm32_iwdg_of_match);
+
static int stm32_iwdg_probe(struct platform_device *pdev)
{
struct watchdog_device *wdd;
+ const struct of_device_id *match;
struct stm32_iwdg *wdt;
struct resource *res;
- void __iomem *regs;
- struct clk *clk;
int ret;
+ match = of_match_device(stm32_iwdg_of_match, &pdev->dev);
+ if (!match)
+ return -ENODEV;
+
+ wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ wdt->has_pclk = match->data;
+
/* This is the timer base. */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- regs = devm_ioremap_resource(&pdev->dev, res);
- if (IS_ERR(regs)) {
+ wdt->regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(wdt->regs)) {
dev_err(&pdev->dev, "Could not get resource\n");
- return PTR_ERR(regs);
+ return PTR_ERR(wdt->regs);
}
- clk = devm_clk_get(&pdev->dev, NULL);
- if (IS_ERR(clk)) {
- dev_err(&pdev->dev, "Unable to get clock\n");
- return PTR_ERR(clk);
- }
-
- ret = clk_prepare_enable(clk);
- if (ret) {
- dev_err(&pdev->dev, "Unable to prepare clock %p\n", clk);
+ ret = stm32_iwdg_clk_init(pdev, wdt);
+ if (ret)
return ret;
- }
-
- /*
- * Allocate our watchdog driver data, which has the
- * struct watchdog_device nested within it.
- */
- wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
- if (!wdt) {
- ret = -ENOMEM;
- goto err;
- }
-
- /* Initialize struct stm32_iwdg. */
- wdt->regs = regs;
- wdt->clk = clk;
- wdt->rate = clk_get_rate(clk);
/* Initialize struct watchdog_device. */
wdd = &wdt->wdd;
@@ -217,7 +253,8 @@ static int stm32_iwdg_probe(struct platform_device *pdev)
return 0;
err:
- clk_disable_unprepare(clk);
+ clk_disable_unprepare(wdt->clk_lsi);
+ clk_disable_unprepare(wdt->clk_pclk);
return ret;
}
@@ -227,23 +264,18 @@ static int stm32_iwdg_remove(struct platform_device *pdev)
struct stm32_iwdg *wdt = platform_get_drvdata(pdev);
watchdog_unregister_device(&wdt->wdd);
- clk_disable_unprepare(wdt->clk);
+ clk_disable_unprepare(wdt->clk_lsi);
+ clk_disable_unprepare(wdt->clk_pclk);
return 0;
}
-static const struct of_device_id stm32_iwdg_of_match[] = {
- { .compatible = "st,stm32-iwdg" },
- { /* end node */ }
-};
-MODULE_DEVICE_TABLE(of, stm32_iwdg_of_match);
-
static struct platform_driver stm32_iwdg_driver = {
.probe = stm32_iwdg_probe,
.remove = stm32_iwdg_remove,
.driver = {
.name = "iwdg",
- .of_match_table = stm32_iwdg_of_match,
+ .of_match_table = of_match_ptr(stm32_iwdg_of_match),
},
};
module_platform_driver(stm32_iwdg_driver);
--
2.7.4

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