Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 273 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-stm32-lp.c b/drivers/pwm/pwm-stm32-lp.c
new file mode 100644
index 000000000..c8a847fcb
--- /dev/null
+++ b/drivers/pwm/pwm-stm32-lp.c
@@ -0,0 +1,273 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * STM32 Low-Power Timer PWM driver
+ *
+ * Copyright (C) STMicroelectronics 2017
+ *
+ * Author: Gerald Baeza <gerald.baeza@st.com>
+ *
+ * Inspired by Gerald Baeza's pwm-stm32 driver
+ */
+
+#include <linux/bitfield.h>
+#include <linux/mfd/stm32-lptimer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+
+struct stm32_pwm_lp {
+	struct pwm_chip chip;
+	struct clk *clk;
+	struct regmap *regmap;
+};
+
+static inline struct stm32_pwm_lp *to_stm32_pwm_lp(struct pwm_chip *chip)
+{
+	return container_of(chip, struct stm32_pwm_lp, chip);
+}
+
+/* STM32 Low-Power Timer is preceded by a configurable power-of-2 prescaler */
+#define STM32_LPTIM_MAX_PRESCALER	128
+
+static int stm32_pwm_lp_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			      const struct pwm_state *state)
+{
+	struct stm32_pwm_lp *priv = to_stm32_pwm_lp(chip);
+	unsigned long long prd, div, dty;
+	struct pwm_state cstate;
+	u32 val, mask, cfgr, presc = 0;
+	bool reenable;
+	int ret;
+
+	pwm_get_state(pwm, &cstate);
+	reenable = !cstate.enabled;
+
+	if (!state->enabled) {
+		if (cstate.enabled) {
+			/* Disable LP timer */
+			ret = regmap_write(priv->regmap, STM32_LPTIM_CR, 0);
+			if (ret)
+				return ret;
+			/* disable clock to PWM counter */
+			clk_disable(priv->clk);
+		}
+		return 0;
+	}
+
+	/* Calculate the period and prescaler value */
+	div = (unsigned long long)clk_get_rate(priv->clk) * state->period;
+	do_div(div, NSEC_PER_SEC);
+	if (!div) {
+		/* Clock is too slow to achieve requested period. */
+		dev_dbg(priv->chip.dev, "Can't reach %llu ns\n", state->period);
+		return -EINVAL;
+	}
+
+	prd = div;
+	while (div > STM32_LPTIM_MAX_ARR) {
+		presc++;
+		if ((1 << presc) > STM32_LPTIM_MAX_PRESCALER) {
+			dev_err(priv->chip.dev, "max prescaler exceeded\n");
+			return -EINVAL;
+		}
+		div = prd >> presc;
+	}
+	prd = div;
+
+	/* Calculate the duty cycle */
+	dty = prd * state->duty_cycle;
+	do_div(dty, state->period);
+
+	if (!cstate.enabled) {
+		/* enable clock to drive PWM counter */
+		ret = clk_enable(priv->clk);
+		if (ret)
+			return ret;
+	}
+
+	ret = regmap_read(priv->regmap, STM32_LPTIM_CFGR, &cfgr);
+	if (ret)
+		goto err;
+
+	if ((FIELD_GET(STM32_LPTIM_PRESC, cfgr) != presc) ||
+	    (FIELD_GET(STM32_LPTIM_WAVPOL, cfgr) != state->polarity)) {
+		val = FIELD_PREP(STM32_LPTIM_PRESC, presc);
+		val |= FIELD_PREP(STM32_LPTIM_WAVPOL, state->polarity);
+		mask = STM32_LPTIM_PRESC | STM32_LPTIM_WAVPOL;
+
+		/* Must disable LP timer to modify CFGR */
+		reenable = true;
+		ret = regmap_write(priv->regmap, STM32_LPTIM_CR, 0);
+		if (ret)
+			goto err;
+
+		ret = regmap_update_bits(priv->regmap, STM32_LPTIM_CFGR, mask,
+					 val);
+		if (ret)
+			goto err;
+	}
+
+	if (reenable) {
+		/* Must (re)enable LP timer to modify CMP & ARR */
+		ret = regmap_write(priv->regmap, STM32_LPTIM_CR,
+				   STM32_LPTIM_ENABLE);
+		if (ret)
+			goto err;
+	}
+
+	ret = regmap_write(priv->regmap, STM32_LPTIM_ARR, prd - 1);
+	if (ret)
+		goto err;
+
+	ret = regmap_write(priv->regmap, STM32_LPTIM_CMP, prd - (1 + dty));
+	if (ret)
+		goto err;
+
+	/* ensure CMP & ARR registers are properly written */
+	ret = regmap_read_poll_timeout(priv->regmap, STM32_LPTIM_ISR, val,
+				       (val & STM32_LPTIM_CMPOK_ARROK) == STM32_LPTIM_CMPOK_ARROK,
+				       100, 1000);
+	if (ret) {
+		dev_err(priv->chip.dev, "ARR/CMP registers write issue\n");
+		goto err;
+	}
+	ret = regmap_write(priv->regmap, STM32_LPTIM_ICR,
+			   STM32_LPTIM_CMPOKCF_ARROKCF);
+	if (ret)
+		goto err;
+
+	if (reenable) {
+		/* Start LP timer in continuous mode */
+		ret = regmap_update_bits(priv->regmap, STM32_LPTIM_CR,
+					 STM32_LPTIM_CNTSTRT,
+					 STM32_LPTIM_CNTSTRT);
+		if (ret) {
+			regmap_write(priv->regmap, STM32_LPTIM_CR, 0);
+			goto err;
+		}
+	}
+
+	return 0;
+err:
+	if (!cstate.enabled)
+		clk_disable(priv->clk);
+
+	return ret;
+}
+
+static void stm32_pwm_lp_get_state(struct pwm_chip *chip,
+				   struct pwm_device *pwm,
+				   struct pwm_state *state)
+{
+	struct stm32_pwm_lp *priv = to_stm32_pwm_lp(chip);
+	unsigned long rate = clk_get_rate(priv->clk);
+	u32 val, presc, prd;
+	u64 tmp;
+
+	regmap_read(priv->regmap, STM32_LPTIM_CR, &val);
+	state->enabled = !!FIELD_GET(STM32_LPTIM_ENABLE, val);
+	/* Keep PWM counter clock refcount in sync with PWM initial state */
+	if (state->enabled)
+		clk_enable(priv->clk);
+
+	regmap_read(priv->regmap, STM32_LPTIM_CFGR, &val);
+	presc = FIELD_GET(STM32_LPTIM_PRESC, val);
+	state->polarity = FIELD_GET(STM32_LPTIM_WAVPOL, val);
+
+	regmap_read(priv->regmap, STM32_LPTIM_ARR, &prd);
+	tmp = prd + 1;
+	tmp = (tmp << presc) * NSEC_PER_SEC;
+	state->period = DIV_ROUND_CLOSEST_ULL(tmp, rate);
+
+	regmap_read(priv->regmap, STM32_LPTIM_CMP, &val);
+	tmp = prd - val;
+	tmp = (tmp << presc) * NSEC_PER_SEC;
+	state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, rate);
+}
+
+static const struct pwm_ops stm32_pwm_lp_ops = {
+	.owner = THIS_MODULE,
+	.apply = stm32_pwm_lp_apply,
+	.get_state = stm32_pwm_lp_get_state,
+};
+
+static int stm32_pwm_lp_probe(struct platform_device *pdev)
+{
+	struct stm32_lptimer *ddata = dev_get_drvdata(pdev->dev.parent);
+	struct stm32_pwm_lp *priv;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->regmap = ddata->regmap;
+	priv->clk = ddata->clk;
+	priv->chip.base = -1;
+	priv->chip.dev = &pdev->dev;
+	priv->chip.ops = &stm32_pwm_lp_ops;
+	priv->chip.npwm = 1;
+	priv->chip.of_xlate = of_pwm_xlate_with_flags;
+	priv->chip.of_pwm_n_cells = 3;
+
+	ret = pwmchip_add(&priv->chip);
+	if (ret < 0)
+		return ret;
+
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+}
+
+static int stm32_pwm_lp_remove(struct platform_device *pdev)
+{
+	struct stm32_pwm_lp *priv = platform_get_drvdata(pdev);
+
+	return pwmchip_remove(&priv->chip);
+}
+
+static int __maybe_unused stm32_pwm_lp_suspend(struct device *dev)
+{
+	struct stm32_pwm_lp *priv = dev_get_drvdata(dev);
+	struct pwm_state state;
+
+	pwm_get_state(&priv->chip.pwms[0], &state);
+	if (state.enabled) {
+		dev_err(dev, "The consumer didn't stop us (%s)\n",
+			priv->chip.pwms[0].label);
+		return -EBUSY;
+	}
+
+	return pinctrl_pm_select_sleep_state(dev);
+}
+
+static int __maybe_unused stm32_pwm_lp_resume(struct device *dev)
+{
+	return pinctrl_pm_select_default_state(dev);
+}
+
+static SIMPLE_DEV_PM_OPS(stm32_pwm_lp_pm_ops, stm32_pwm_lp_suspend,
+			 stm32_pwm_lp_resume);
+
+static const struct of_device_id stm32_pwm_lp_of_match[] = {
+	{ .compatible = "st,stm32-pwm-lp", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, stm32_pwm_lp_of_match);
+
+static struct platform_driver stm32_pwm_lp_driver = {
+	.probe	= stm32_pwm_lp_probe,
+	.remove	= stm32_pwm_lp_remove,
+	.driver	= {
+		.name = "stm32-pwm-lp",
+		.of_match_table = of_match_ptr(stm32_pwm_lp_of_match),
+		.pm = &stm32_pwm_lp_pm_ops,
+	},
+};
+module_platform_driver(stm32_pwm_lp_driver);
+
+MODULE_ALIAS("platform:stm32-pwm-lp");
+MODULE_DESCRIPTION("STMicroelectronics STM32 PWM LP driver");
+MODULE_LICENSE("GPL v2");