1 files changed, 423 insertions, 0 deletions
diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
new file mode 100644
index 0000000000..6206d2dc3d
--- /dev/null
+++ b/drivers/counter/stm32-timer-cnt.c
@@ -0,0 +1,423 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * STM32 Timer Encoder and Counter driver
+ *
+ * Copyright (C) STMicroelectronics 2018
+ *
+ * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
+ *
+ */
+#include <linux/counter.h>
+#include <linux/mfd/stm32-timers.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+
+#define TIM_CCMR_CCXS	(BIT(8) | BIT(0))
+#define TIM_CCMR_MASK	(TIM_CCMR_CC1S | TIM_CCMR_CC2S | \
+			 TIM_CCMR_IC1F | TIM_CCMR_IC2F)
+#define TIM_CCER_MASK	(TIM_CCER_CC1P | TIM_CCER_CC1NP | \
+			 TIM_CCER_CC2P | TIM_CCER_CC2NP)
+
+struct stm32_timer_regs {
+	u32 cr1;
+	u32 cnt;
+	u32 smcr;
+	u32 arr;
+};
+
+struct stm32_timer_cnt {
+	struct regmap *regmap;
+	struct clk *clk;
+	u32 max_arr;
+	bool enabled;
+	struct stm32_timer_regs bak;
+};
+
+static const enum counter_function stm32_count_functions[] = {
+	COUNTER_FUNCTION_INCREASE,
+	COUNTER_FUNCTION_QUADRATURE_X2_A,
+	COUNTER_FUNCTION_QUADRATURE_X2_B,
+	COUNTER_FUNCTION_QUADRATURE_X4,
+};
+
+static int stm32_count_read(struct counter_device *counter,
+			    struct counter_count *count, u64 *val)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+	u32 cnt;
+
+	regmap_read(priv->regmap, TIM_CNT, &cnt);
+	*val = cnt;
+
+	return 0;
+}
+
+static int stm32_count_write(struct counter_device *counter,
+			     struct counter_count *count, const u64 val)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+	u32 ceiling;
+
+	regmap_read(priv->regmap, TIM_ARR, &ceiling);
+	if (val > ceiling)
+		return -EINVAL;
+
+	return regmap_write(priv->regmap, TIM_CNT, val);
+}
+
+static int stm32_count_function_read(struct counter_device *counter,
+				     struct counter_count *count,
+				     enum counter_function *function)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+	u32 smcr;
+
+	regmap_read(priv->regmap, TIM_SMCR, &smcr);
+
+	switch (smcr & TIM_SMCR_SMS) {
+	case TIM_SMCR_SMS_SLAVE_MODE_DISABLED:
+		*function = COUNTER_FUNCTION_INCREASE;
+		return 0;
+	case TIM_SMCR_SMS_ENCODER_MODE_1:
+		*function = COUNTER_FUNCTION_QUADRATURE_X2_A;
+		return 0;
+	case TIM_SMCR_SMS_ENCODER_MODE_2:
+		*function = COUNTER_FUNCTION_QUADRATURE_X2_B;
+		return 0;
+	case TIM_SMCR_SMS_ENCODER_MODE_3:
+		*function = COUNTER_FUNCTION_QUADRATURE_X4;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int stm32_count_function_write(struct counter_device *counter,
+				      struct counter_count *count,
+				      enum counter_function function)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+	u32 cr1, sms;
+
+	switch (function) {
+	case COUNTER_FUNCTION_INCREASE:
+		sms = TIM_SMCR_SMS_SLAVE_MODE_DISABLED;
+		break;
+	case COUNTER_FUNCTION_QUADRATURE_X2_A:
+		sms = TIM_SMCR_SMS_ENCODER_MODE_1;
+		break;
+	case COUNTER_FUNCTION_QUADRATURE_X2_B:
+		sms = TIM_SMCR_SMS_ENCODER_MODE_2;
+		break;
+	case COUNTER_FUNCTION_QUADRATURE_X4:
+		sms = TIM_SMCR_SMS_ENCODER_MODE_3;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* Store enable status */
+	regmap_read(priv->regmap, TIM_CR1, &cr1);
+
+	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
+
+	regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms);
+
+	/* Make sure that registers are updated */
+	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
+
+	/* Restore the enable status */
+	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, cr1);
+
+	return 0;
+}
+
+static int stm32_count_direction_read(struct counter_device *counter,
+				      struct counter_count *count,
+				      enum counter_count_direction *direction)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+	u32 cr1;
+
+	regmap_read(priv->regmap, TIM_CR1, &cr1);
+	*direction = (cr1 & TIM_CR1_DIR) ? COUNTER_COUNT_DIRECTION_BACKWARD :
+		COUNTER_COUNT_DIRECTION_FORWARD;
+
+	return 0;
+}
+
+static int stm32_count_ceiling_read(struct counter_device *counter,
+				    struct counter_count *count, u64 *ceiling)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+	u32 arr;
+
+	regmap_read(priv->regmap, TIM_ARR, &arr);
+
+	*ceiling = arr;
+
+	return 0;
+}
+
+static int stm32_count_ceiling_write(struct counter_device *counter,
+				     struct counter_count *count, u64 ceiling)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+
+	if (ceiling > priv->max_arr)
+		return -ERANGE;
+
+	/* TIMx_ARR register shouldn't be buffered (ARPE=0) */
+	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
+	regmap_write(priv->regmap, TIM_ARR, ceiling);
+
+	return 0;
+}
+
+static int stm32_count_enable_read(struct counter_device *counter,
+				   struct counter_count *count, u8 *enable)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+	u32 cr1;
+
+	regmap_read(priv->regmap, TIM_CR1, &cr1);
+
+	*enable = cr1 & TIM_CR1_CEN;
+
+	return 0;
+}
+
+static int stm32_count_enable_write(struct counter_device *counter,
+				    struct counter_count *count, u8 enable)
+{
+	struct stm32_timer_cnt *const priv = counter_priv(counter);
+	u32 cr1;
+
+	if (enable) {
+		regmap_read(priv->regmap, TIM_CR1, &cr1);
+		if (!(cr1 & TIM_CR1_CEN))
+			clk_enable(priv->clk);
+
+		regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN,
+				   TIM_CR1_CEN);
+	} else {
+		regmap_read(priv->regmap, TIM_CR1, &cr1);
+		regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
+		if (cr1 & TIM_CR1_CEN)
+			clk_disable(priv->clk);
+	}
+
+	/* Keep enabled state to properly handle low power states */
+	priv->enabled = enable;
+
+	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),
+	COUNTER_COMP_CEILING(stm32_count_ceiling_read,
+			     stm32_count_ceiling_write),
+};
+
+static const enum counter_synapse_action stm32_synapse_actions[] = {
+	COUNTER_SYNAPSE_ACTION_NONE,
+	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
+};
+
+static int stm32_action_read(struct counter_device *counter,
+			     struct counter_count *count,
+			     struct counter_synapse *synapse,
+			     enum counter_synapse_action *action)
+{
+	enum counter_function function;
+	int err;
+
+	err = stm32_count_function_read(counter, count, &function);
+	if (err)
+		return err;
+
+	switch (function) {
+	case COUNTER_FUNCTION_INCREASE:
+		/* counts on internal clock when CEN=1 */
+		*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)
+			*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)
+			*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;
+		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,
+};
+
+static struct counter_signal stm32_signals[] = {
+	{
+		.id = 0,
+		.name = "Channel 1 Quadrature A"
+	},
+	{
+		.id = 1,
+		.name = "Channel 1 Quadrature B"
+	}
+};
+
+static struct counter_synapse stm32_count_synapses[] = {
+	{
+		.actions_list = stm32_synapse_actions,
+		.num_actions = ARRAY_SIZE(stm32_synapse_actions),
+		.signal = &stm32_signals[0]
+	},
+	{
+		.actions_list = stm32_synapse_actions,
+		.num_actions = ARRAY_SIZE(stm32_synapse_actions),
+		.signal = &stm32_signals[1]
+	}
+};
+
+static struct counter_count stm32_counts = {
+	.id = 0,
+	.name = "Channel 1 Count",
+	.functions_list = stm32_count_functions,
+	.num_functions = ARRAY_SIZE(stm32_count_functions),
+	.synapses = stm32_count_synapses,
+	.num_synapses = ARRAY_SIZE(stm32_count_synapses),
+	.ext = stm32_count_ext,
+	.num_ext = ARRAY_SIZE(stm32_count_ext)
+};
+
+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;
+
+	if (IS_ERR_OR_NULL(ddata))
+		return -EINVAL;
+
+	counter = devm_counter_alloc(dev, sizeof(*priv));
+	if (!counter)
+		return -ENOMEM;
+
+	priv = counter_priv(counter);
+
+	priv->regmap = ddata->regmap;
+	priv->clk = ddata->clk;
+	priv->max_arr = ddata->max_arr;
+
+	counter->name = dev_name(dev);
+	counter->parent = dev;
+	counter->ops = &stm32_timer_cnt_ops;
+	counter->counts = &stm32_counts;
+	counter->num_counts = 1;
+	counter->signals = stm32_signals;
+	counter->num_signals = ARRAY_SIZE(stm32_signals);
+
+	platform_set_drvdata(pdev, priv);
+
+	/* Reset input selector to its default input */
+	regmap_write(priv->regmap, TIM_TISEL, 0x0);
+
+	/* Register Counter device */
+	ret = devm_counter_add(dev, counter);
+	if (ret < 0)
+		dev_err_probe(dev, ret, "Failed to add counter\n");
+
+	return ret;
+}
+
+static int __maybe_unused stm32_timer_cnt_suspend(struct device *dev)
+{
+	struct stm32_timer_cnt *priv = dev_get_drvdata(dev);
+
+	/* Only take care of enabled counter: don't disturb other MFD child */
+	if (priv->enabled) {
+		/* Backup registers that may get lost in low power mode */
+		regmap_read(priv->regmap, TIM_SMCR, &priv->bak.smcr);
+		regmap_read(priv->regmap, TIM_ARR, &priv->bak.arr);
+		regmap_read(priv->regmap, TIM_CNT, &priv->bak.cnt);
+		regmap_read(priv->regmap, TIM_CR1, &priv->bak.cr1);
+
+		/* Disable the counter */
+		regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
+		clk_disable(priv->clk);
+	}
+
+	return pinctrl_pm_select_sleep_state(dev);
+}
+
+static int __maybe_unused stm32_timer_cnt_resume(struct device *dev)
+{
+	struct stm32_timer_cnt *priv = dev_get_drvdata(dev);
+	int ret;
+
+	ret = pinctrl_pm_select_default_state(dev);
+	if (ret)
+		return ret;
+
+	if (priv->enabled) {
+		clk_enable(priv->clk);
+
+		/* Restore registers that may have been lost */
+		regmap_write(priv->regmap, TIM_SMCR, priv->bak.smcr);
+		regmap_write(priv->regmap, TIM_ARR, priv->bak.arr);
+		regmap_write(priv->regmap, TIM_CNT, priv->bak.cnt);
+
+		/* Also re-enables the counter */
+		regmap_write(priv->regmap, TIM_CR1, priv->bak.cr1);
+	}
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(stm32_timer_cnt_pm_ops, stm32_timer_cnt_suspend,
+			 stm32_timer_cnt_resume);
+
+static const struct of_device_id stm32_timer_cnt_of_match[] = {
+	{ .compatible = "st,stm32-timer-counter", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, stm32_timer_cnt_of_match);
+
+static struct platform_driver stm32_timer_cnt_driver = {
+	.probe = stm32_timer_cnt_probe,
+	.driver = {
+		.name = "stm32-timer-counter",
+		.of_match_table = stm32_timer_cnt_of_match,
+		.pm = &stm32_timer_cnt_pm_ops,
+	},
+};
+module_platform_driver(stm32_timer_cnt_driver);
+
+MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");
+MODULE_ALIAS("platform:stm32-timer-counter");
+MODULE_DESCRIPTION("STMicroelectronics STM32 TIMER counter driver");
+MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(COUNTER);