diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/counter/stm32-timer-cnt.c | 138 |
1 files changed, 137 insertions, 1 deletions
diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c index e1c0a502b74c..9fcafec682b7 100644 --- a/drivers/counter/stm32-timer-cnt.c +++ b/drivers/counter/stm32-timer-cnt.c @@ -8,6 +8,7 @@ * */ #include <linux/counter.h> +#include <linux/interrupt.h> #include <linux/mfd/stm32-timers.h> #include <linux/mod_devicetable.h> #include <linux/module.h> @@ -43,6 +44,9 @@ struct stm32_timer_cnt { struct stm32_timer_regs bak; bool has_encoder; unsigned int nchannels; + unsigned int nr_irqs; + spinlock_t lock; /* protects nb_ovf */ + u64 nb_ovf; }; static const enum counter_function stm32_count_functions[] = { @@ -258,6 +262,32 @@ static int stm32_count_prescaler_write(struct counter_device *counter, return regmap_write(priv->regmap, TIM_PSC, psc); } +static int stm32_count_nb_ovf_read(struct counter_device *counter, + struct counter_count *count, u64 *val) +{ + struct stm32_timer_cnt *const priv = counter_priv(counter); + unsigned long irqflags; + + spin_lock_irqsave(&priv->lock, irqflags); + *val = priv->nb_ovf; + spin_unlock_irqrestore(&priv->lock, irqflags); + + return 0; +} + +static int stm32_count_nb_ovf_write(struct counter_device *counter, + struct counter_count *count, u64 val) +{ + struct stm32_timer_cnt *const priv = counter_priv(counter); + unsigned long irqflags; + + spin_lock_irqsave(&priv->lock, irqflags); + priv->nb_ovf = val; + spin_unlock_irqrestore(&priv->lock, irqflags); + + return 0; +} + static struct counter_comp stm32_count_ext[] = { COUNTER_COMP_DIRECTION(stm32_count_direction_read), COUNTER_COMP_ENABLE(stm32_count_enable_read, stm32_count_enable_write), @@ -265,6 +295,7 @@ static struct counter_comp stm32_count_ext[] = { stm32_count_ceiling_write), COUNTER_COMP_COUNT_U64("prescaler", stm32_count_prescaler_read, stm32_count_prescaler_write), + COUNTER_COMP_COUNT_U64("num_overflows", stm32_count_nb_ovf_read, stm32_count_nb_ovf_write), }; static const enum counter_synapse_action stm32_clock_synapse_actions[] = { @@ -322,12 +353,57 @@ static int stm32_action_read(struct counter_device *counter, } } +static int stm32_count_events_configure(struct counter_device *counter) +{ + struct stm32_timer_cnt *const priv = counter_priv(counter); + struct counter_event_node *event_node; + u32 dier = 0; + + list_for_each_entry(event_node, &counter->events_list, l) { + switch (event_node->event) { + case COUNTER_EVENT_OVERFLOW_UNDERFLOW: + /* first clear possibly latched UIF before enabling */ + if (!regmap_test_bits(priv->regmap, TIM_DIER, TIM_DIER_UIE)) + regmap_write(priv->regmap, TIM_SR, (u32)~TIM_SR_UIF); + dier |= TIM_DIER_UIE; + break; + default: + /* should never reach this path */ + return -EINVAL; + } + } + + /* Enable / disable all events at once, from events_list, so write all DIER bits */ + regmap_write(priv->regmap, TIM_DIER, dier); + + return 0; +} + +static int stm32_count_watch_validate(struct counter_device *counter, + const struct counter_watch *watch) +{ + struct stm32_timer_cnt *const priv = counter_priv(counter); + + /* Interrupts are optional */ + if (!priv->nr_irqs) + return -EOPNOTSUPP; + + switch (watch->event) { + case COUNTER_EVENT_OVERFLOW_UNDERFLOW: + return 0; + default: + return -EINVAL; + } +} + static const struct counter_ops stm32_timer_cnt_ops = { .count_read = stm32_count_read, .count_write = stm32_count_write, .function_read = stm32_count_function_read, .function_write = stm32_count_function_write, .action_read = stm32_action_read, + .events_configure = stm32_count_events_configure, + .watch_validate = stm32_count_watch_validate, }; static int stm32_count_clk_get_freq(struct counter_device *counter, @@ -417,6 +493,37 @@ static struct counter_count stm32_counts = { .num_ext = ARRAY_SIZE(stm32_count_ext) }; +static irqreturn_t stm32_timer_cnt_isr(int irq, void *ptr) +{ + struct counter_device *counter = ptr; + struct stm32_timer_cnt *const priv = counter_priv(counter); + u32 clr = GENMASK(31, 0); /* SR flags can be cleared by writing 0 (wr 1 has no effect) */ + u32 sr, dier; + + regmap_read(priv->regmap, TIM_SR, &sr); + regmap_read(priv->regmap, TIM_DIER, &dier); + /* + * Some status bits in SR don't match with the enable bits in DIER. Only take care of + * the possibly enabled bits in DIER (that matches in between SR and DIER). + */ + dier &= TIM_DIER_UIE; + sr &= dier; + + if (sr & TIM_SR_UIF) { + spin_lock(&priv->lock); + priv->nb_ovf++; + spin_unlock(&priv->lock); + counter_push_event(counter, COUNTER_EVENT_OVERFLOW_UNDERFLOW, 0); + dev_dbg(counter->parent, "COUNTER_EVENT_OVERFLOW_UNDERFLOW\n"); + /* SR flags can be cleared by writing 0, only clear relevant flag */ + clr &= ~TIM_SR_UIF; + } + + regmap_write(priv->regmap, TIM_SR, clr); + + return IRQ_HANDLED; +}; + static void stm32_timer_cnt_detect_channels(struct device *dev, struct stm32_timer_cnt *priv) { @@ -480,7 +587,7 @@ static int stm32_timer_cnt_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct stm32_timer_cnt *priv; struct counter_device *counter; - int ret; + int i, ret; if (IS_ERR_OR_NULL(ddata)) return -EINVAL; @@ -494,6 +601,7 @@ static int stm32_timer_cnt_probe(struct platform_device *pdev) priv->regmap = ddata->regmap; priv->clk = ddata->clk; priv->max_arr = ddata->max_arr; + priv->nr_irqs = ddata->nr_irqs; ret = stm32_timer_cnt_probe_encoder(dev, priv); if (ret) @@ -509,8 +617,36 @@ static int stm32_timer_cnt_probe(struct platform_device *pdev) counter->signals = stm32_signals; counter->num_signals = ARRAY_SIZE(stm32_signals); + spin_lock_init(&priv->lock); + platform_set_drvdata(pdev, priv); + /* STM32 Timers can have either 1 global, or 4 dedicated interrupts (optional) */ + if (priv->nr_irqs == 1) { + /* All events reported through the global interrupt */ + ret = devm_request_irq(&pdev->dev, ddata->irq[0], stm32_timer_cnt_isr, + 0, dev_name(dev), counter); + if (ret) { + dev_err(dev, "Failed to request irq %d (err %d)\n", + ddata->irq[0], ret); + return ret; + } + } else { + for (i = 0; i < priv->nr_irqs; i++) { + /* Only take care of update IRQ for overflow events */ + if (i != STM32_TIMERS_IRQ_UP) + continue; + + ret = devm_request_irq(&pdev->dev, ddata->irq[i], stm32_timer_cnt_isr, + 0, dev_name(dev), counter); + if (ret) { + dev_err(dev, "Failed to request irq %d (err %d)\n", + ddata->irq[i], ret); + return ret; + } + } + } + /* Reset input selector to its default input */ regmap_write(priv->regmap, TIM_TISEL, 0x0); |