Re: [PATCH V4 2/4] watchdog: stm32: add pclk feature for stm32mp1
From: Guenter Roeck
Date: Thu Jun 21 2018 - 12:53:45 EST
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 ?
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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