Adding upstream version 6.6.15.upstream/6.6.15

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

1 files changed, 358 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-imx27.c b/drivers/pwm/pwm-imx27.c
new file mode 100644
index 0000000000..29a3089c53
--- /dev/null
+++ b/drivers/pwm/pwm-imx27.c
@@ -0,0 +1,358 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * simple driver for PWM (Pulse Width Modulator) controller
+ *
+ * Derived from pxa PWM driver by eric miao <eric.miao@marvell.com>
+ *
+ * Limitations:
+ * - When disabled the output is driven to 0 independent of the configured
+ *   polarity.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+#define MX3_PWMCR			0x00    /* PWM Control Register */
+#define MX3_PWMSR			0x04    /* PWM Status Register */
+#define MX3_PWMSAR			0x0C    /* PWM Sample Register */
+#define MX3_PWMPR			0x10    /* PWM Period Register */
+
+#define MX3_PWMCR_FWM			GENMASK(27, 26)
+#define MX3_PWMCR_STOPEN		BIT(25)
+#define MX3_PWMCR_DOZEN			BIT(24)
+#define MX3_PWMCR_WAITEN		BIT(23)
+#define MX3_PWMCR_DBGEN			BIT(22)
+#define MX3_PWMCR_BCTR			BIT(21)
+#define MX3_PWMCR_HCTR			BIT(20)
+
+#define MX3_PWMCR_POUTC			GENMASK(19, 18)
+#define MX3_PWMCR_POUTC_NORMAL		0
+#define MX3_PWMCR_POUTC_INVERTED	1
+#define MX3_PWMCR_POUTC_OFF		2
+
+#define MX3_PWMCR_CLKSRC		GENMASK(17, 16)
+#define MX3_PWMCR_CLKSRC_OFF		0
+#define MX3_PWMCR_CLKSRC_IPG		1
+#define MX3_PWMCR_CLKSRC_IPG_HIGH	2
+#define MX3_PWMCR_CLKSRC_IPG_32K	3
+
+#define MX3_PWMCR_PRESCALER		GENMASK(15, 4)
+
+#define MX3_PWMCR_SWR			BIT(3)
+
+#define MX3_PWMCR_REPEAT		GENMASK(2, 1)
+#define MX3_PWMCR_REPEAT_1X		0
+#define MX3_PWMCR_REPEAT_2X		1
+#define MX3_PWMCR_REPEAT_4X		2
+#define MX3_PWMCR_REPEAT_8X		3
+
+#define MX3_PWMCR_EN			BIT(0)
+
+#define MX3_PWMSR_FWE			BIT(6)
+#define MX3_PWMSR_CMP			BIT(5)
+#define MX3_PWMSR_ROV			BIT(4)
+#define MX3_PWMSR_FE			BIT(3)
+
+#define MX3_PWMSR_FIFOAV		GENMASK(2, 0)
+#define MX3_PWMSR_FIFOAV_EMPTY		0
+#define MX3_PWMSR_FIFOAV_1WORD		1
+#define MX3_PWMSR_FIFOAV_2WORDS		2
+#define MX3_PWMSR_FIFOAV_3WORDS		3
+#define MX3_PWMSR_FIFOAV_4WORDS		4
+
+#define MX3_PWMCR_PRESCALER_SET(x)	FIELD_PREP(MX3_PWMCR_PRESCALER, (x) - 1)
+#define MX3_PWMCR_PRESCALER_GET(x)	(FIELD_GET(MX3_PWMCR_PRESCALER, \
+						   (x)) + 1)
+
+#define MX3_PWM_SWR_LOOP		5
+
+/* PWMPR register value of 0xffff has the same effect as 0xfffe */
+#define MX3_PWMPR_MAX			0xfffe
+
+struct pwm_imx27_chip {
+	struct clk	*clk_ipg;
+	struct clk	*clk_per;
+	void __iomem	*mmio_base;
+	struct pwm_chip	chip;
+
+	/*
+	 * The driver cannot read the current duty cycle from the hardware if
+	 * the hardware is disabled. Cache the last programmed duty cycle
+	 * value to return in that case.
+	 */
+	unsigned int duty_cycle;
+};
+
+#define to_pwm_imx27_chip(chip)	container_of(chip, struct pwm_imx27_chip, chip)
+
+static int pwm_imx27_clk_prepare_enable(struct pwm_imx27_chip *imx)
+{
+	int ret;
+
+	ret = clk_prepare_enable(imx->clk_ipg);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(imx->clk_per);
+	if (ret) {
+		clk_disable_unprepare(imx->clk_ipg);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void pwm_imx27_clk_disable_unprepare(struct pwm_imx27_chip *imx)
+{
+	clk_disable_unprepare(imx->clk_per);
+	clk_disable_unprepare(imx->clk_ipg);
+}
+
+static int pwm_imx27_get_state(struct pwm_chip *chip,
+			       struct pwm_device *pwm, struct pwm_state *state)
+{
+	struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip);
+	u32 period, prescaler, pwm_clk, val;
+	u64 tmp;
+	int ret;
+
+	ret = pwm_imx27_clk_prepare_enable(imx);
+	if (ret < 0)
+		return ret;
+
+	val = readl(imx->mmio_base + MX3_PWMCR);
+
+	if (val & MX3_PWMCR_EN)
+		state->enabled = true;
+	else
+		state->enabled = false;
+
+	switch (FIELD_GET(MX3_PWMCR_POUTC, val)) {
+	case MX3_PWMCR_POUTC_NORMAL:
+		state->polarity = PWM_POLARITY_NORMAL;
+		break;
+	case MX3_PWMCR_POUTC_INVERTED:
+		state->polarity = PWM_POLARITY_INVERSED;
+		break;
+	default:
+		dev_warn(chip->dev, "can't set polarity, output disconnected");
+	}
+
+	prescaler = MX3_PWMCR_PRESCALER_GET(val);
+	pwm_clk = clk_get_rate(imx->clk_per);
+	val = readl(imx->mmio_base + MX3_PWMPR);
+	period = val >= MX3_PWMPR_MAX ? MX3_PWMPR_MAX : val;
+
+	/* PWMOUT (Hz) = PWMCLK / (PWMPR + 2) */
+	tmp = NSEC_PER_SEC * (u64)(period + 2) * prescaler;
+	state->period = DIV_ROUND_UP_ULL(tmp, pwm_clk);
+
+	/*
+	 * PWMSAR can be read only if PWM is enabled. If the PWM is disabled,
+	 * use the cached value.
+	 */
+	if (state->enabled)
+		val = readl(imx->mmio_base + MX3_PWMSAR);
+	else
+		val = imx->duty_cycle;
+
+	tmp = NSEC_PER_SEC * (u64)(val) * prescaler;
+	state->duty_cycle = DIV_ROUND_UP_ULL(tmp, pwm_clk);
+
+	pwm_imx27_clk_disable_unprepare(imx);
+
+	return 0;
+}
+
+static void pwm_imx27_sw_reset(struct pwm_chip *chip)
+{
+	struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip);
+	struct device *dev = chip->dev;
+	int wait_count = 0;
+	u32 cr;
+
+	writel(MX3_PWMCR_SWR, imx->mmio_base + MX3_PWMCR);
+	do {
+		usleep_range(200, 1000);
+		cr = readl(imx->mmio_base + MX3_PWMCR);
+	} while ((cr & MX3_PWMCR_SWR) &&
+		 (wait_count++ < MX3_PWM_SWR_LOOP));
+
+	if (cr & MX3_PWMCR_SWR)
+		dev_warn(dev, "software reset timeout\n");
+}
+
+static void pwm_imx27_wait_fifo_slot(struct pwm_chip *chip,
+				     struct pwm_device *pwm)
+{
+	struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip);
+	struct device *dev = chip->dev;
+	unsigned int period_ms;
+	int fifoav;
+	u32 sr;
+
+	sr = readl(imx->mmio_base + MX3_PWMSR);
+	fifoav = FIELD_GET(MX3_PWMSR_FIFOAV, sr);
+	if (fifoav == MX3_PWMSR_FIFOAV_4WORDS) {
+		period_ms = DIV_ROUND_UP_ULL(pwm_get_period(pwm),
+					 NSEC_PER_MSEC);
+		msleep(period_ms);
+
+		sr = readl(imx->mmio_base + MX3_PWMSR);
+		if (fifoav == FIELD_GET(MX3_PWMSR_FIFOAV, sr))
+			dev_warn(dev, "there is no free FIFO slot\n");
+	}
+}
+
+static int pwm_imx27_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			   const struct pwm_state *state)
+{
+	unsigned long period_cycles, duty_cycles, prescale;
+	struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip);
+	struct pwm_state cstate;
+	unsigned long long c;
+	unsigned long long clkrate;
+	int ret;
+	u32 cr;
+
+	pwm_get_state(pwm, &cstate);
+
+	clkrate = clk_get_rate(imx->clk_per);
+	c = clkrate * state->period;
+
+	do_div(c, NSEC_PER_SEC);
+	period_cycles = c;
+
+	prescale = period_cycles / 0x10000 + 1;
+
+	period_cycles /= prescale;
+	c = clkrate * state->duty_cycle;
+	do_div(c, NSEC_PER_SEC);
+	duty_cycles = c;
+	duty_cycles /= prescale;
+
+	/*
+	 * according to imx pwm RM, the real period value should be PERIOD
+	 * value in PWMPR plus 2.
+	 */
+	if (period_cycles > 2)
+		period_cycles -= 2;
+	else
+		period_cycles = 0;
+
+	/*
+	 * Wait for a free FIFO slot if the PWM is already enabled, and flush
+	 * the FIFO if the PWM was disabled and is about to be enabled.
+	 */
+	if (cstate.enabled) {
+		pwm_imx27_wait_fifo_slot(chip, pwm);
+	} else {
+		ret = pwm_imx27_clk_prepare_enable(imx);
+		if (ret)
+			return ret;
+
+		pwm_imx27_sw_reset(chip);
+	}
+
+	writel(duty_cycles, imx->mmio_base + MX3_PWMSAR);
+	writel(period_cycles, imx->mmio_base + MX3_PWMPR);
+
+	/*
+	 * Store the duty cycle for future reference in cases where the
+	 * MX3_PWMSAR register can't be read (i.e. when the PWM is disabled).
+	 */
+	imx->duty_cycle = duty_cycles;
+
+	cr = MX3_PWMCR_PRESCALER_SET(prescale) |
+	     MX3_PWMCR_STOPEN | MX3_PWMCR_DOZEN | MX3_PWMCR_WAITEN |
+	     FIELD_PREP(MX3_PWMCR_CLKSRC, MX3_PWMCR_CLKSRC_IPG_HIGH) |
+	     MX3_PWMCR_DBGEN;
+
+	if (state->polarity == PWM_POLARITY_INVERSED)
+		cr |= FIELD_PREP(MX3_PWMCR_POUTC,
+				MX3_PWMCR_POUTC_INVERTED);
+
+	if (state->enabled)
+		cr |= MX3_PWMCR_EN;
+
+	writel(cr, imx->mmio_base + MX3_PWMCR);
+
+	if (!state->enabled)
+		pwm_imx27_clk_disable_unprepare(imx);
+
+	return 0;
+}
+
+static const struct pwm_ops pwm_imx27_ops = {
+	.apply = pwm_imx27_apply,
+	.get_state = pwm_imx27_get_state,
+	.owner = THIS_MODULE,
+};
+
+static const struct of_device_id pwm_imx27_dt_ids[] = {
+	{ .compatible = "fsl,imx27-pwm", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, pwm_imx27_dt_ids);
+
+static int pwm_imx27_probe(struct platform_device *pdev)
+{
+	struct pwm_imx27_chip *imx;
+	int ret;
+	u32 pwmcr;
+
+	imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL);
+	if (imx == NULL)
+		return -ENOMEM;
+
+	imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
+	if (IS_ERR(imx->clk_ipg))
+		return dev_err_probe(&pdev->dev, PTR_ERR(imx->clk_ipg),
+				     "getting ipg clock failed\n");
+
+	imx->clk_per = devm_clk_get(&pdev->dev, "per");
+	if (IS_ERR(imx->clk_per))
+		return dev_err_probe(&pdev->dev, PTR_ERR(imx->clk_per),
+				     "failed to get peripheral clock\n");
+
+	imx->chip.ops = &pwm_imx27_ops;
+	imx->chip.dev = &pdev->dev;
+	imx->chip.npwm = 1;
+
+	imx->mmio_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(imx->mmio_base))
+		return PTR_ERR(imx->mmio_base);
+
+	ret = pwm_imx27_clk_prepare_enable(imx);
+	if (ret)
+		return ret;
+
+	/* keep clks on if pwm is running */
+	pwmcr = readl(imx->mmio_base + MX3_PWMCR);
+	if (!(pwmcr & MX3_PWMCR_EN))
+		pwm_imx27_clk_disable_unprepare(imx);
+
+	return devm_pwmchip_add(&pdev->dev, &imx->chip);
+}
+
+static struct platform_driver imx_pwm_driver = {
+	.driver = {
+		.name = "pwm-imx27",
+		.of_match_table = pwm_imx27_dt_ids,
+	},
+	.probe = pwm_imx27_probe,
+};
+module_platform_driver(imx_pwm_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");