1 files changed, 95 insertions, 76 deletions

diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c
index dc9717551d39..0f5bdb0e395e 100644
--- a/drivers/pwm/pwm-pxa.c
+++ b/drivers/pwm/pwm-pxa.c
@@ -1,16 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * drivers/pwm/pwm-pxa.c
  *
  * simple driver for PWM (Pulse Width Modulator) controller
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  * 2008-02-13	initial version
- * 		eric miao <eric.miao@marvell.com>
+ *		eric miao <eric.miao@marvell.com>
+ *
+ * Links to reference manuals for some of the supported PWM chips can be found
+ * in Documentation/arch/arm/marvell.rst.
+ *
+ * Limitations:
+ * - When PWM is stopped, the current PWM period stops abruptly at the next
+ *   input clock (PWMCR_SD is set) and the output is driven to inactive.
  */
 
+#include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/platform_device.h>
@@ -19,6 +24,8 @@
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/pwm.h>
+#include <linux/of.h>
+#include <linux/reset.h>
 
 #include <asm/div64.h>
 
@@ -43,7 +50,6 @@ MODULE_DEVICE_TABLE(platform, pwm_id_table);
 #define PWMDCR_FD	(1 << 10)
 
 struct pxa_pwm_chip {
-	struct pwm_chip	chip;
 	struct device	*dev;
 
 	struct clk	*clk;
@@ -52,7 +58,7 @@ struct pxa_pwm_chip {
 
 static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip)
 {
-	return container_of(chip, struct pxa_pwm_chip, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
 /*
@@ -60,13 +66,12 @@ static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip)
  * duty_ns   = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
  */
 static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
-			  int duty_ns, int period_ns)
+			  u64 duty_ns, u64 period_ns)
 {
 	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
 	unsigned long long c;
 	unsigned long period_cycles, prescale, pv, dc;
 	unsigned long offset;
-	int rc;
 
 	offset = pwm->hwpwm ? 0x10 : 0;
 
@@ -86,112 +91,126 @@ static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	if (duty_ns == period_ns)
 		dc = PWMDCR_FD;
 	else
-		dc = (pv + 1) * duty_ns / period_ns;
+		dc = mul_u64_u64_div_u64(pv + 1, duty_ns, period_ns);
 
-	/* NOTE: the clock to PWM has to be enabled first
-	 * before writing to the registers
-	 */
-	rc = clk_prepare_enable(pc->clk);
-	if (rc < 0)
-		return rc;
-
-	writel(prescale, pc->mmio_base + offset + PWMCR);
+	writel(prescale | PWMCR_SD, pc->mmio_base + offset + PWMCR);
 	writel(dc, pc->mmio_base + offset + PWMDCR);
 	writel(pv, pc->mmio_base + offset + PWMPCR);
 
-	clk_disable_unprepare(pc->clk);
 	return 0;
 }
 
-static int pxa_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+static int pxa_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			 const struct pwm_state *state)
 {
 	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
+	u64 duty_cycle;
+	int err;
 
-	return clk_prepare_enable(pc->clk);
-}
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
 
-static void pxa_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
+	err = clk_prepare_enable(pc->clk);
+	if (err)
+		return err;
+
+	duty_cycle = state->enabled ? state->duty_cycle : 0;
+
+	err = pxa_pwm_config(chip, pwm, duty_cycle, state->period);
+	if (err) {
+		clk_disable_unprepare(pc->clk);
+		return err;
+	}
+
+	if (state->enabled && !pwm->state.enabled)
+		return 0;
 
 	clk_disable_unprepare(pc->clk);
+
+	if (!state->enabled && pwm->state.enabled)
+		clk_disable_unprepare(pc->clk);
+
+	return 0;
 }
 
-static struct pwm_ops pxa_pwm_ops = {
-	.config = pxa_pwm_config,
-	.enable = pxa_pwm_enable,
-	.disable = pxa_pwm_disable,
-	.owner = THIS_MODULE,
+static const struct pwm_ops pxa_pwm_ops = {
+	.apply = pxa_pwm_apply,
 };
 
+#ifdef CONFIG_OF
+/*
+ * Device tree users must create one device instance for each PWM channel.
+ * Hence we dispense with the HAS_SECONDARY_PWM and "tell" the original driver
+ * code that this is a single channel pxa25x-pwm.  Currently all devices are
+ * supported identically.
+ */
+static const struct of_device_id pwm_of_match[] = {
+	{ .compatible = "marvell,pxa250-pwm", .data = &pwm_id_table[0]},
+	{ .compatible = "marvell,pxa270-pwm", .data = &pwm_id_table[0]},
+	{ .compatible = "marvell,pxa168-pwm", .data = &pwm_id_table[0]},
+	{ .compatible = "marvell,pxa910-pwm", .data = &pwm_id_table[0]},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, pwm_of_match);
+#else
+#define pwm_of_match NULL
+#endif
+
 static int pwm_probe(struct platform_device *pdev)
 {
 	const struct platform_device_id *id = platform_get_device_id(pdev);
-	struct pxa_pwm_chip *pwm;
-	struct resource *r;
+	struct pwm_chip *chip;
+	struct pxa_pwm_chip *pc;
+	struct device *dev = &pdev->dev;
+	struct reset_control *rst;
 	int ret = 0;
 
-	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
-	if (pwm == NULL) {
-		dev_err(&pdev->dev, "failed to allocate memory\n");
-		return -ENOMEM;
-	}
+	if (IS_ENABLED(CONFIG_OF) && id == NULL)
+		id = of_device_get_match_data(dev);
 
-	pwm->clk = devm_clk_get(&pdev->dev, NULL);
-	if (IS_ERR(pwm->clk))
-		return PTR_ERR(pwm->clk);
+	if (id == NULL)
+		return -EINVAL;
 
-	pwm->chip.dev = &pdev->dev;
-	pwm->chip.ops = &pxa_pwm_ops;
-	pwm->chip.base = -1;
-	pwm->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1;
+	chip = devm_pwmchip_alloc(dev, (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1,
+				  sizeof(*pc));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	pc = to_pxa_pwm_chip(chip);
 
-	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r);
-	if (IS_ERR(pwm->mmio_base))
-		return PTR_ERR(pwm->mmio_base);
+	pc->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(pc->clk))
+		return dev_err_probe(dev, PTR_ERR(pc->clk), "Failed to get clock\n");
 
-	ret = pwmchip_add(&pwm->chip);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
-		return ret;
-	}
+	rst = devm_reset_control_get_optional_exclusive_deasserted(dev, NULL);
+	if (IS_ERR(rst))
+		return PTR_ERR(rst);
 
-	platform_set_drvdata(pdev, pwm);
-	return 0;
-}
+	chip->ops = &pxa_pwm_ops;
 
-static int pwm_remove(struct platform_device *pdev)
-{
-	struct pxa_pwm_chip *chip;
+	if (IS_ENABLED(CONFIG_OF))
+		chip->of_xlate = of_pwm_single_xlate;
+
+	pc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(pc->mmio_base))
+		return PTR_ERR(pc->mmio_base);
 
-	chip = platform_get_drvdata(pdev);
-	if (chip == NULL)
-		return -ENODEV;
+	ret = devm_pwmchip_add(dev, chip);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "pwmchip_add() failed\n");
 
-	return pwmchip_remove(&chip->chip);
+	return 0;
 }
 
 static struct platform_driver pwm_driver = {
 	.driver		= {
 		.name	= "pxa25x-pwm",
-		.owner	= THIS_MODULE,
+		.of_match_table = pwm_of_match,
 	},
 	.probe		= pwm_probe,
-	.remove		= pwm_remove,
 	.id_table	= pwm_id_table,
 };
 
-static int __init pwm_init(void)
-{
-	return platform_driver_register(&pwm_driver);
-}
-arch_initcall(pwm_init);
-
-static void __exit pwm_exit(void)
-{
-	platform_driver_unregister(&pwm_driver);
-}
-module_exit(pwm_exit);
+module_platform_driver(pwm_driver);
 
+MODULE_DESCRIPTION("PXA Pulse Width Modulator driver");
 MODULE_LICENSE("GPL v2");