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Date: Fri, 22 Jun 2018 11:15:19 +0200
From: Ludovic BARRE <ludovic.barre@...com>
To: Guenter Roeck <linux@...ck-us.net>
CC: Wim Van Sebroeck <wim@...ux-watchdog.org>,
Rob Herring <robh+dt@...nel.org>,
Maxime Coquelin <mcoquelin.stm32@...il.com>,
Alexandre Torgue <alexandre.torgue@...com>,
<linux-watchdog@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>
Subject: Re: [PATCH V4 2/4] watchdog: stm32: add pclk feature for stm32mp1
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@...com>
>>
>> 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@...com>
>> ---
>> 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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