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path: root/drivers/watchdog/stm32_iwdg.c
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Diffstat (limited to 'drivers/watchdog/stm32_iwdg.c')
-rw-r--r--drivers/watchdog/stm32_iwdg.c150
1 files changed, 76 insertions, 74 deletions
diff --git a/drivers/watchdog/stm32_iwdg.c b/drivers/watchdog/stm32_iwdg.c
index e00e3b3526c6..d569a3634d9b 100644
--- a/drivers/watchdog/stm32_iwdg.c
+++ b/drivers/watchdog/stm32_iwdg.c
@@ -34,36 +34,44 @@
#define KR_KEY_EWA 0x5555 /* write access enable */
#define KR_KEY_DWA 0x0000 /* write access disable */
-/* IWDG_PR register bit values */
-#define PR_4 0x00 /* prescaler set to 4 */
-#define PR_8 0x01 /* prescaler set to 8 */
-#define PR_16 0x02 /* prescaler set to 16 */
-#define PR_32 0x03 /* prescaler set to 32 */
-#define PR_64 0x04 /* prescaler set to 64 */
-#define PR_128 0x05 /* prescaler set to 128 */
-#define PR_256 0x06 /* prescaler set to 256 */
+/* IWDG_PR register */
+#define PR_SHIFT 2
+#define PR_MIN BIT(PR_SHIFT)
/* IWDG_RLR register values */
-#define RLR_MIN 0x07C /* min value supported by reload register */
-#define RLR_MAX 0xFFF /* max value supported by reload register */
+#define RLR_MIN 0x2 /* min value recommended */
+#define RLR_MAX GENMASK(11, 0) /* max value of reload register */
/* IWDG_SR register bit mask */
-#define FLAG_PVU BIT(0) /* Watchdog prescaler value update */
-#define FLAG_RVU BIT(1) /* Watchdog counter reload value update */
+#define SR_PVU BIT(0) /* Watchdog prescaler value update */
+#define SR_RVU BIT(1) /* Watchdog counter reload value update */
/* set timeout to 100000 us */
#define TIMEOUT_US 100000
#define SLEEP_US 1000
-#define HAS_PCLK true
+struct stm32_iwdg_data {
+ bool has_pclk;
+ u32 max_prescaler;
+};
+
+static const struct stm32_iwdg_data stm32_iwdg_data = {
+ .has_pclk = false,
+ .max_prescaler = 256,
+};
+
+static const struct stm32_iwdg_data stm32mp1_iwdg_data = {
+ .has_pclk = true,
+ .max_prescaler = 1024,
+};
struct stm32_iwdg {
struct watchdog_device wdd;
+ const struct stm32_iwdg_data *data;
void __iomem *regs;
struct clk *clk_lsi;
struct clk *clk_pclk;
unsigned int rate;
- bool has_pclk;
};
static inline u32 reg_read(void __iomem *base, u32 reg)
@@ -79,31 +87,35 @@ static inline void reg_write(void __iomem *base, u32 reg, u32 val)
static int stm32_iwdg_start(struct watchdog_device *wdd)
{
struct stm32_iwdg *wdt = watchdog_get_drvdata(wdd);
- u32 val = FLAG_PVU | FLAG_RVU;
- u32 reload;
+ u32 tout, presc, iwdg_rlr, iwdg_pr, iwdg_sr;
int ret;
dev_dbg(wdd->parent, "%s\n", __func__);
- /* prescaler fixed to 256 */
- reload = clamp_t(unsigned int, ((wdd->timeout * wdt->rate) / 256) - 1,
- RLR_MIN, RLR_MAX);
+ tout = clamp_t(unsigned int, wdd->timeout,
+ wdd->min_timeout, wdd->max_hw_heartbeat_ms / 1000);
+
+ presc = DIV_ROUND_UP(tout * wdt->rate, RLR_MAX + 1);
+
+ /* The prescaler is align on power of 2 and start at 2 ^ PR_SHIFT. */
+ presc = roundup_pow_of_two(presc);
+ iwdg_pr = presc <= 1 << PR_SHIFT ? 0 : ilog2(presc) - PR_SHIFT;
+ iwdg_rlr = ((tout * wdt->rate) / presc) - 1;
/* enable write access */
reg_write(wdt->regs, IWDG_KR, KR_KEY_EWA);
/* set prescaler & reload registers */
- reg_write(wdt->regs, IWDG_PR, PR_256); /* prescaler fix to 256 */
- reg_write(wdt->regs, IWDG_RLR, reload);
+ reg_write(wdt->regs, IWDG_PR, iwdg_pr);
+ reg_write(wdt->regs, IWDG_RLR, iwdg_rlr);
reg_write(wdt->regs, IWDG_KR, KR_KEY_ENABLE);
/* wait for the registers to be updated (max 100ms) */
- ret = readl_relaxed_poll_timeout(wdt->regs + IWDG_SR, val,
- !(val & (FLAG_PVU | FLAG_RVU)),
+ ret = readl_relaxed_poll_timeout(wdt->regs + IWDG_SR, iwdg_sr,
+ !(iwdg_sr & (SR_PVU | SR_RVU)),
SLEEP_US, TIMEOUT_US);
if (ret) {
- dev_err(wdd->parent,
- "Fail to set prescaler or reload registers\n");
+ dev_err(wdd->parent, "Fail to set prescaler, reload regs\n");
return ret;
}
@@ -138,38 +150,52 @@ static int stm32_iwdg_set_timeout(struct watchdog_device *wdd,
return 0;
}
+static void stm32_clk_disable_unprepare(void *data)
+{
+ clk_disable_unprepare(data);
+}
+
static int stm32_iwdg_clk_init(struct platform_device *pdev,
struct stm32_iwdg *wdt)
{
+ struct device *dev = &pdev->dev;
u32 ret;
- wdt->clk_lsi = devm_clk_get(&pdev->dev, "lsi");
+ wdt->clk_lsi = devm_clk_get(dev, "lsi");
if (IS_ERR(wdt->clk_lsi)) {
- dev_err(&pdev->dev, "Unable to get lsi clock\n");
+ dev_err(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 (wdt->data->has_pclk) {
+ wdt->clk_pclk = devm_clk_get(dev, "pclk");
if (IS_ERR(wdt->clk_pclk)) {
- dev_err(&pdev->dev, "Unable to get pclk clock\n");
+ dev_err(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");
+ dev_err(dev, "Unable to prepare pclk clock\n");
return ret;
}
+ ret = devm_add_action_or_reset(dev,
+ stm32_clk_disable_unprepare,
+ wdt->clk_pclk);
+ if (ret)
+ 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);
+ dev_err(dev, "Unable to prepare lsi clock\n");
return ret;
}
+ ret = devm_add_action_or_reset(dev, stm32_clk_disable_unprepare,
+ wdt->clk_lsi);
+ if (ret)
+ return ret;
wdt->rate = clk_get_rate(wdt->clk_lsi);
@@ -191,35 +217,31 @@ static const struct watchdog_ops stm32_iwdg_ops = {
};
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 },
+ { .compatible = "st,stm32-iwdg", .data = &stm32_iwdg_data },
+ { .compatible = "st,stm32mp1-iwdg", .data = &stm32mp1_iwdg_data },
{ /* end node */ }
};
MODULE_DEVICE_TABLE(of, stm32_iwdg_of_match);
static int stm32_iwdg_probe(struct platform_device *pdev)
{
+ struct device *dev = &pdev->dev;
struct watchdog_device *wdd;
- const struct of_device_id *match;
struct stm32_iwdg *wdt;
- struct resource *res;
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);
+ wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
- wdt->has_pclk = match->data;
+ wdt->data = of_device_get_match_data(&pdev->dev);
+ if (!wdt->data)
+ return -ENODEV;
/* This is the timer base. */
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- wdt->regs = devm_ioremap_resource(&pdev->dev, res);
+ wdt->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(wdt->regs)) {
- dev_err(&pdev->dev, "Could not get resource\n");
+ dev_err(dev, "Could not get resource\n");
return PTR_ERR(wdt->regs);
}
@@ -229,50 +251,30 @@ static int stm32_iwdg_probe(struct platform_device *pdev)
/* Initialize struct watchdog_device. */
wdd = &wdt->wdd;
+ wdd->parent = dev;
wdd->info = &stm32_iwdg_info;
wdd->ops = &stm32_iwdg_ops;
- wdd->min_timeout = ((RLR_MIN + 1) * 256) / wdt->rate;
- wdd->max_hw_heartbeat_ms = ((RLR_MAX + 1) * 256 * 1000) / wdt->rate;
- wdd->parent = &pdev->dev;
+ wdd->min_timeout = DIV_ROUND_UP((RLR_MIN + 1) * PR_MIN, wdt->rate);
+ wdd->max_hw_heartbeat_ms = ((RLR_MAX + 1) * wdt->data->max_prescaler *
+ 1000) / wdt->rate;
watchdog_set_drvdata(wdd, wdt);
watchdog_set_nowayout(wdd, WATCHDOG_NOWAYOUT);
+ watchdog_init_timeout(wdd, 0, dev);
- ret = watchdog_init_timeout(wdd, 0, &pdev->dev);
- if (ret)
- dev_warn(&pdev->dev,
- "unable to set timeout value, using default\n");
-
- ret = watchdog_register_device(wdd);
+ ret = devm_watchdog_register_device(dev, wdd);
if (ret) {
- dev_err(&pdev->dev, "failed to register watchdog device\n");
- goto err;
+ dev_err(dev, "failed to register watchdog device\n");
+ return ret;
}
platform_set_drvdata(pdev, wdt);
return 0;
-err:
- clk_disable_unprepare(wdt->clk_lsi);
- clk_disable_unprepare(wdt->clk_pclk);
-
- return ret;
-}
-
-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_lsi);
- clk_disable_unprepare(wdt->clk_pclk);
-
- return 0;
}
static struct platform_driver stm32_iwdg_driver = {
.probe = stm32_iwdg_probe,
- .remove = stm32_iwdg_remove,
.driver = {
.name = "iwdg",
.of_match_table = of_match_ptr(stm32_iwdg_of_match),
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.