pwm: imx: Split into two drivers

The two PWM implementations called v1 (for i.MX1 and i.MX21) and v2 (for
i.MX27 and later) have nothing in common apart from needing two clocks
named "per" and "ipg" and being integrated in a SoC named i.MX.

So split the file containing the two disjunct drivers into two files and
two complete separate drivers.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[thierry.reding@gmail.com: fix a modular build issue]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

1 files changed, 361 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-imx27.c b/drivers/pwm/pwm-imx27.c
new file mode 100644
index 000000000000..8b8b1c6b7f29
--- /dev/null
+++ b/drivers/pwm/pwm-imx27.c
@@ -0,0 +1,361 @@
+// 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>
+ */
+
+#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/of_device.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;
+};
+
+#define to_pwm_imx27_chip(chip)	container_of(chip, struct pwm_imx27_chip, chip)
+
+static int pwm_imx27_clk_prepare_enable(struct pwm_chip *chip)
+{
+	struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip);
+	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_chip *chip)
+{
+	struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip);
+
+	clk_disable_unprepare(imx->clk_per);
+	clk_disable_unprepare(imx->clk_ipg);
+}
+
+static void 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, ret, val;
+	u64 tmp;
+
+	ret = pwm_imx27_clk_prepare_enable(chip);
+	if (ret < 0)
+		return;
+
+	val = readl(imx->mmio_base + MX3_PWMCR);
+
+	if (val & MX3_PWMCR_EN) {
+		state->enabled = true;
+		ret = pwm_imx27_clk_prepare_enable(chip);
+		if (ret)
+			return;
+	} 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);
+	pwm_clk = DIV_ROUND_CLOSEST_ULL(pwm_clk, prescaler);
+	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);
+	state->period = DIV_ROUND_CLOSEST_ULL(tmp, pwm_clk);
+
+	/* PWMSAR can be read only if PWM is enabled */
+	if (state->enabled) {
+		val = readl(imx->mmio_base + MX3_PWMSAR);
+		tmp = NSEC_PER_SEC * (u64)(val);
+		state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, pwm_clk);
+	} else {
+		state->duty_cycle = 0;
+	}
+
+	pwm_imx27_clk_disable_unprepare(chip);
+}
+
+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(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,
+			   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;
+	int ret;
+	u32 cr;
+
+	pwm_get_state(pwm, &cstate);
+
+	if (state->enabled) {
+		c = clk_get_rate(imx->clk_per);
+		c *= state->period;
+
+		do_div(c, 1000000000);
+		period_cycles = c;
+
+		prescale = period_cycles / 0x10000 + 1;
+
+		period_cycles /= prescale;
+		c = (unsigned long long)period_cycles * state->duty_cycle;
+		do_div(c, state->period);
+		duty_cycles = c;
+
+		/*
+		 * 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(chip);
+			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);
+
+		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 | MX3_PWMCR_EN;
+
+		if (state->polarity == PWM_POLARITY_INVERSED)
+			cr |= FIELD_PREP(MX3_PWMCR_POUTC,
+					MX3_PWMCR_POUTC_INVERTED);
+
+		writel(cr, imx->mmio_base + MX3_PWMCR);
+	} else if (cstate.enabled) {
+		writel(0, imx->mmio_base + MX3_PWMCR);
+
+		pwm_imx27_clk_disable_unprepare(chip);
+	}
+
+	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;
+	struct resource *r;
+
+	imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL);
+	if (imx == NULL)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, imx);
+
+	imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
+	if (IS_ERR(imx->clk_ipg)) {
+		dev_err(&pdev->dev, "getting ipg clock failed with %ld\n",
+				PTR_ERR(imx->clk_ipg));
+		return PTR_ERR(imx->clk_ipg);
+	}
+
+	imx->clk_per = devm_clk_get(&pdev->dev, "per");
+	if (IS_ERR(imx->clk_per)) {
+		int ret = PTR_ERR(imx->clk_per);
+
+		if (ret != -EPROBE_DEFER)
+			dev_err(&pdev->dev,
+				"failed to get peripheral clock: %d\n",
+				ret);
+
+		return ret;
+	}
+
+	imx->chip.ops = &pwm_imx27_ops;
+	imx->chip.dev = &pdev->dev;
+	imx->chip.base = -1;
+	imx->chip.npwm = 1;
+
+	imx->chip.of_xlate = of_pwm_xlate_with_flags;
+	imx->chip.of_pwm_n_cells = 3;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	imx->mmio_base = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(imx->mmio_base))
+		return PTR_ERR(imx->mmio_base);
+
+	return pwmchip_add(&imx->chip);
+}
+
+static int pwm_imx27_remove(struct platform_device *pdev)
+{
+	struct pwm_imx27_chip *imx;
+
+	imx = platform_get_drvdata(pdev);
+
+	pwm_imx27_clk_disable_unprepare(&imx->chip);
+
+	return pwmchip_remove(&imx->chip);
+}
+
+static struct platform_driver imx_pwm_driver = {
+	.driver = {
+		.name = "pwm-imx27",
+		.of_match_table = pwm_imx27_dt_ids,
+	},
+	.probe = pwm_imx27_probe,
+	.remove = pwm_imx27_remove,
+};
+module_platform_driver(imx_pwm_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");