1 files changed, 447 insertions, 14 deletions

diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
index 6206d2dc3d47..0664ef969f79 100644
--- a/drivers/counter/stm32-timer-cnt.c
+++ b/drivers/counter/stm32-timer-cnt.c
@@ -8,9 +8,11 @@
  *
  */
 #include <linux/counter.h>
+#include <linux/interrupt.h>
 #include <linux/mfd/stm32-timers.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/types.h>
@@ -21,6 +23,12 @@
 #define TIM_CCER_MASK	(TIM_CCER_CC1P | TIM_CCER_CC1NP | \
 			 TIM_CCER_CC2P | TIM_CCER_CC2NP)
 
+#define STM32_CH1_SIG		0
+#define STM32_CH2_SIG		1
+#define STM32_CLOCK_SIG		2
+#define STM32_CH3_SIG		3
+#define STM32_CH4_SIG		4
+
 struct stm32_timer_regs {
 	u32 cr1;
 	u32 cnt;
@@ -34,6 +42,11 @@ struct stm32_timer_cnt {
 	u32 max_arr;
 	bool enabled;
 	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[] = {
@@ -107,12 +120,18 @@ static int stm32_count_function_write(struct counter_device *counter,
 		sms = TIM_SMCR_SMS_SLAVE_MODE_DISABLED;
 		break;
 	case COUNTER_FUNCTION_QUADRATURE_X2_A:
+		if (!priv->has_encoder)
+			return -EOPNOTSUPP;
 		sms = TIM_SMCR_SMS_ENCODER_MODE_1;
 		break;
 	case COUNTER_FUNCTION_QUADRATURE_X2_B:
+		if (!priv->has_encoder)
+			return -EOPNOTSUPP;
 		sms = TIM_SMCR_SMS_ENCODER_MODE_2;
 		break;
 	case COUNTER_FUNCTION_QUADRATURE_X4:
+		if (!priv->has_encoder)
+			return -EOPNOTSUPP;
 		sms = TIM_SMCR_SMS_ENCODER_MODE_3;
 		break;
 	default:
@@ -216,11 +235,108 @@ static int stm32_count_enable_write(struct counter_device *counter,
 	return 0;
 }
 
+static int stm32_count_prescaler_read(struct counter_device *counter,
+				      struct counter_count *count, u64 *prescaler)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+	u32 psc;
+
+	regmap_read(priv->regmap, TIM_PSC, &psc);
+
+	*prescaler = psc + 1;
+
+	return 0;
+}
+
+static int stm32_count_prescaler_write(struct counter_device *counter,
+				       struct counter_count *count, u64 prescaler)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+	u32 psc;
+
+	if (!prescaler || prescaler > MAX_TIM_PSC + 1)
+		return -ERANGE;
+
+	psc = prescaler - 1;
+
+	return regmap_write(priv->regmap, TIM_PSC, psc);
+}
+
+static int stm32_count_cap_read(struct counter_device *counter,
+				struct counter_count *count,
+				size_t ch, u64 *cap)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+	u32 ccrx;
+
+	if (ch >= priv->nchannels)
+		return -EOPNOTSUPP;
+
+	switch (ch) {
+	case 0:
+		regmap_read(priv->regmap, TIM_CCR1, &ccrx);
+		break;
+	case 1:
+		regmap_read(priv->regmap, TIM_CCR2, &ccrx);
+		break;
+	case 2:
+		regmap_read(priv->regmap, TIM_CCR3, &ccrx);
+		break;
+	case 3:
+		regmap_read(priv->regmap, TIM_CCR4, &ccrx);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	dev_dbg(counter->parent, "CCR%zu: 0x%08x\n", ch + 1, ccrx);
+
+	*cap = ccrx;
+
+	return 0;
+}
+
+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 DEFINE_COUNTER_ARRAY_CAPTURE(stm32_count_cap_array, 4);
+
 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),
 	COUNTER_COMP_CEILING(stm32_count_ceiling_read,
 			     stm32_count_ceiling_write),
+	COUNTER_COMP_COUNT_U64("prescaler", stm32_count_prescaler_read,
+			       stm32_count_prescaler_write),
+	COUNTER_COMP_ARRAY_CAPTURE(stm32_count_cap_read, NULL, stm32_count_cap_array),
+	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[] = {
+	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
 };
 
 static const enum counter_synapse_action stm32_synapse_actions[] = {
@@ -243,25 +359,152 @@ static int stm32_action_read(struct counter_device *counter,
 	switch (function) {
 	case COUNTER_FUNCTION_INCREASE:
 		/* counts on internal clock when CEN=1 */
-		*action = COUNTER_SYNAPSE_ACTION_NONE;
+		if (synapse->signal->id == STM32_CLOCK_SIG)
+			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
+		else
+			*action = COUNTER_SYNAPSE_ACTION_NONE;
 		return 0;
 	case COUNTER_FUNCTION_QUADRATURE_X2_A:
 		/* counts up/down on TI1FP1 edge depending on TI2FP2 level */
-		if (synapse->signal->id == count->synapses[0].signal->id)
+		if (synapse->signal->id == STM32_CH1_SIG)
 			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 		else
 			*action = COUNTER_SYNAPSE_ACTION_NONE;
 		return 0;
 	case COUNTER_FUNCTION_QUADRATURE_X2_B:
 		/* counts up/down on TI2FP2 edge depending on TI1FP1 level */
-		if (synapse->signal->id == count->synapses[1].signal->id)
+		if (synapse->signal->id == STM32_CH2_SIG)
 			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 		else
 			*action = COUNTER_SYNAPSE_ACTION_NONE;
 		return 0;
 	case COUNTER_FUNCTION_QUADRATURE_X4:
 		/* counts up/down on both TI1FP1 and TI2FP2 edges */
-		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
+		if (synapse->signal->id == STM32_CH1_SIG || synapse->signal->id == STM32_CH2_SIG)
+			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
+		else
+			*action = COUNTER_SYNAPSE_ACTION_NONE;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+struct stm32_count_cc_regs {
+	u32 ccmr_reg;
+	u32 ccmr_mask;
+	u32 ccmr_bits;
+	u32 ccer_bits;
+};
+
+static const struct stm32_count_cc_regs stm32_cc[] = {
+	{ TIM_CCMR1, TIM_CCMR_CC1S, TIM_CCMR_CC1S_TI1,
+		TIM_CCER_CC1E | TIM_CCER_CC1P | TIM_CCER_CC1NP },
+	{ TIM_CCMR1, TIM_CCMR_CC2S, TIM_CCMR_CC2S_TI2,
+		TIM_CCER_CC2E | TIM_CCER_CC2P | TIM_CCER_CC2NP },
+	{ TIM_CCMR2, TIM_CCMR_CC3S, TIM_CCMR_CC3S_TI3,
+		TIM_CCER_CC3E | TIM_CCER_CC3P | TIM_CCER_CC3NP },
+	{ TIM_CCMR2, TIM_CCMR_CC4S, TIM_CCMR_CC4S_TI4,
+		TIM_CCER_CC4E | TIM_CCER_CC4P | TIM_CCER_CC4NP },
+};
+
+static int stm32_count_capture_configure(struct counter_device *counter, unsigned int ch,
+					 bool enable)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+	const struct stm32_count_cc_regs *cc;
+	u32 ccmr, ccer;
+
+	if (ch >= ARRAY_SIZE(stm32_cc) || ch >= priv->nchannels) {
+		dev_err(counter->parent, "invalid ch: %d\n", ch);
+		return -EINVAL;
+	}
+
+	cc = &stm32_cc[ch];
+
+	/*
+	 * configure channel in input capture mode, map channel 1 on TI1, channel2 on TI2...
+	 * Select both edges / non-inverted to trigger a capture.
+	 */
+	if (enable) {
+		/* first clear possibly latched capture flag upon enabling */
+		if (!regmap_test_bits(priv->regmap, TIM_CCER, cc->ccer_bits))
+			regmap_write(priv->regmap, TIM_SR, ~TIM_SR_CC_IF(ch));
+		regmap_update_bits(priv->regmap, cc->ccmr_reg, cc->ccmr_mask,
+				   cc->ccmr_bits);
+		regmap_set_bits(priv->regmap, TIM_CCER, cc->ccer_bits);
+	} else {
+		regmap_clear_bits(priv->regmap, TIM_CCER, cc->ccer_bits);
+		regmap_clear_bits(priv->regmap, cc->ccmr_reg, cc->ccmr_mask);
+	}
+
+	regmap_read(priv->regmap, cc->ccmr_reg, &ccmr);
+	regmap_read(priv->regmap, TIM_CCER, &ccer);
+	dev_dbg(counter->parent, "%s(%s) ch%d 0x%08x 0x%08x\n", __func__, enable ? "ena" : "dis",
+		ch, ccmr, ccer);
+
+	return 0;
+}
+
+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;
+	int i, ret;
+
+	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;
+		case COUNTER_EVENT_CAPTURE:
+			ret = stm32_count_capture_configure(counter, event_node->channel, true);
+			if (ret)
+				return ret;
+			dier |= TIM_DIER_CC_IE(event_node->channel);
+			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);
+
+	/* check for disabled capture events */
+	for (i = 0 ; i < priv->nchannels; i++) {
+		if (!(dier & TIM_DIER_CC_IE(i))) {
+			ret = stm32_count_capture_configure(counter, i, false);
+			if (ret)
+				return ret;
+		}
+	}
+
+	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_CAPTURE:
+		if (watch->channel >= priv->nchannels) {
+			dev_err(counter->parent, "Invalid channel %d\n", watch->channel);
+			return -EINVAL;
+		}
+		return 0;
+	case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
 		return 0;
 	default:
 		return -EINVAL;
@@ -274,35 +517,89 @@ static const struct counter_ops stm32_timer_cnt_ops = {
 	.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,
+				    struct counter_signal *signal, u64 *freq)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+
+	*freq = clk_get_rate(priv->clk);
+
+	return 0;
+}
+
+static struct counter_comp stm32_count_clock_ext[] = {
+	COUNTER_COMP_FREQUENCY(stm32_count_clk_get_freq),
 };
 
 static struct counter_signal stm32_signals[] = {
+	/*
+	 * Need to declare all the signals as a static array, and keep the signals order here,
+	 * even if they're unused or unexisting on some timer instances. It's an abstraction,
+	 * e.g. high level view of the counter features.
+	 *
+	 * Userspace programs may rely on signal0 to be "Channel 1", signal1 to be "Channel 2",
+	 * and so on. When a signal is unexisting, the COUNTER_SYNAPSE_ACTION_NONE can be used,
+	 * to indicate that a signal doesn't affect the counter.
+	 */
 	{
-		.id = 0,
-		.name = "Channel 1 Quadrature A"
+		.id = STM32_CH1_SIG,
+		.name = "Channel 1"
 	},
 	{
-		.id = 1,
-		.name = "Channel 1 Quadrature B"
-	}
+		.id = STM32_CH2_SIG,
+		.name = "Channel 2"
+	},
+	{
+		.id = STM32_CLOCK_SIG,
+		.name = "Clock",
+		.ext = stm32_count_clock_ext,
+		.num_ext = ARRAY_SIZE(stm32_count_clock_ext),
+	},
+	{
+		.id = STM32_CH3_SIG,
+		.name = "Channel 3"
+	},
+	{
+		.id = STM32_CH4_SIG,
+		.name = "Channel 4"
+	},
 };
 
 static struct counter_synapse stm32_count_synapses[] = {
 	{
 		.actions_list = stm32_synapse_actions,
 		.num_actions = ARRAY_SIZE(stm32_synapse_actions),
-		.signal = &stm32_signals[0]
+		.signal = &stm32_signals[STM32_CH1_SIG]
 	},
 	{
 		.actions_list = stm32_synapse_actions,
 		.num_actions = ARRAY_SIZE(stm32_synapse_actions),
-		.signal = &stm32_signals[1]
-	}
+		.signal = &stm32_signals[STM32_CH2_SIG]
+	},
+	{
+		.actions_list = stm32_clock_synapse_actions,
+		.num_actions = ARRAY_SIZE(stm32_clock_synapse_actions),
+		.signal = &stm32_signals[STM32_CLOCK_SIG]
+	},
+	{
+		.actions_list = stm32_synapse_actions,
+		.num_actions = ARRAY_SIZE(stm32_synapse_actions),
+		.signal = &stm32_signals[STM32_CH3_SIG]
+	},
+	{
+		.actions_list = stm32_synapse_actions,
+		.num_actions = ARRAY_SIZE(stm32_synapse_actions),
+		.signal = &stm32_signals[STM32_CH4_SIG]
+	},
 };
 
 static struct counter_count stm32_counts = {
 	.id = 0,
-	.name = "Channel 1 Count",
+	.name = "STM32 Timer Counter",
 	.functions_list = stm32_count_functions,
 	.num_functions = ARRAY_SIZE(stm32_count_functions),
 	.synapses = stm32_count_synapses,
@@ -311,13 +608,111 @@ 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;
+	int i;
+
+	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 | TIM_DIER_CC1IE | TIM_DIER_CC2IE | TIM_DIER_CC3IE | TIM_DIER_CC4IE);
+	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;
+	}
+
+	/* Check capture events */
+	for (i = 0 ; i < priv->nchannels; i++) {
+		if (sr & TIM_SR_CC_IF(i)) {
+			counter_push_event(counter, COUNTER_EVENT_CAPTURE, i);
+			clr &= ~TIM_SR_CC_IF(i);
+			dev_dbg(counter->parent, "COUNTER_EVENT_CAPTURE, %d\n", i);
+		}
+	}
+
+	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)
+{
+	u32 ccer, ccer_backup;
+
+	regmap_read(priv->regmap, TIM_CCER, &ccer_backup);
+	regmap_set_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE);
+	regmap_read(priv->regmap, TIM_CCER, &ccer);
+	regmap_write(priv->regmap, TIM_CCER, ccer_backup);
+	priv->nchannels = hweight32(ccer & TIM_CCER_CCXE);
+
+	dev_dbg(dev, "has %d cc channels\n", priv->nchannels);
+}
+
+/* encoder supported on TIM1 TIM2 TIM3 TIM4 TIM5 TIM8 */
+#define STM32_TIM_ENCODER_SUPPORTED	(BIT(0) | BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(7))
+
+static const char * const stm32_timer_trigger_compat[] = {
+	"st,stm32-timer-trigger",
+	"st,stm32h7-timer-trigger",
+};
+
+static int stm32_timer_cnt_probe_encoder(struct device *dev,
+					 struct stm32_timer_cnt *priv)
+{
+	struct device *parent = dev->parent;
+	struct device_node *tnode = NULL, *pnode = parent->of_node;
+	int i, ret;
+	u32 idx;
+
+	/*
+	 * Need to retrieve the trigger node index from DT, to be able
+	 * to determine if the counter supports encoder mode. It also
+	 * enforce backward compatibility, and allow to support other
+	 * counter modes in this driver (when the timer doesn't support
+	 * encoder).
+	 */
+	for (i = 0; i < ARRAY_SIZE(stm32_timer_trigger_compat) && !tnode; i++)
+		tnode = of_get_compatible_child(pnode, stm32_timer_trigger_compat[i]);
+	if (!tnode) {
+		dev_err(dev, "Can't find trigger node\n");
+		return -ENODATA;
+	}
+
+	ret = of_property_read_u32(tnode, "reg", &idx);
+	if (ret) {
+		dev_err(dev, "Can't get index (%d)\n", ret);
+		return ret;
+	}
+
+	priv->has_encoder = !!(STM32_TIM_ENCODER_SUPPORTED & BIT(idx));
+
+	dev_dbg(dev, "encoder support: %s\n", priv->has_encoder ? "yes" : "no");
+
+	return 0;
+}
+
 static int stm32_timer_cnt_probe(struct platform_device *pdev)
 {
 	struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
 	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;
@@ -331,6 +726,13 @@ 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)
+		return ret;
+
+	stm32_timer_cnt_detect_channels(dev, priv);
 
 	counter->name = dev_name(dev);
 	counter->parent = dev;
@@ -340,8 +742,39 @@ 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, and cc for
+			 * capture events.
+			 */
+			if (i != STM32_TIMERS_IRQ_UP && i != STM32_TIMERS_IRQ_CC)
+				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);