Initial import

1 files changed, 237 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c
new file mode 100644
index 000000000..cb2f7024c
--- /dev/null
+++ b/drivers/pwm/pwm-pxa.c
@@ -0,0 +1,237 @@
+/*
+ * 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>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/pwm.h>
+#include <linux/of_device.h>
+
+#include <asm/div64.h>
+
+#define HAS_SECONDARY_PWM	0x10
+
+static const struct platform_device_id pwm_id_table[] = {
+	/*   PWM    has_secondary_pwm? */
+	{ "pxa25x-pwm", 0 },
+	{ "pxa27x-pwm", HAS_SECONDARY_PWM },
+	{ "pxa168-pwm", 0 },
+	{ "pxa910-pwm", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(platform, pwm_id_table);
+
+/* PWM registers and bits definitions */
+#define PWMCR		(0x00)
+#define PWMDCR		(0x04)
+#define PWMPCR		(0x08)
+
+#define PWMCR_SD	(1 << 6)
+#define PWMDCR_FD	(1 << 10)
+
+struct pxa_pwm_chip {
+	struct pwm_chip	chip;
+	struct device	*dev;
+
+	struct clk	*clk;
+	void __iomem	*mmio_base;
+};
+
+static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip)
+{
+	return container_of(chip, struct pxa_pwm_chip, chip);
+}
+
+/*
+ * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
+ * 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)
+{
+	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;
+
+	c = clk_get_rate(pc->clk);
+	c = c * period_ns;
+	do_div(c, 1000000000);
+	period_cycles = c;
+
+	if (period_cycles < 1)
+		period_cycles = 1;
+	prescale = (period_cycles - 1) / 1024;
+	pv = period_cycles / (prescale + 1) - 1;
+
+	if (prescale > 63)
+		return -EINVAL;
+
+	if (duty_ns == period_ns)
+		dc = PWMDCR_FD;
+	else
+		dc = (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(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)
+{
+	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
+
+	return clk_prepare_enable(pc->clk);
+}
+
+static void pxa_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
+
+	clk_disable_unprepare(pc->clk);
+}
+
+static struct pwm_ops pxa_pwm_ops = {
+	.config = pxa_pwm_config,
+	.enable = pxa_pwm_enable,
+	.disable = pxa_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+#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 const struct platform_device_id *pxa_pwm_get_id_dt(struct device *dev)
+{
+	const struct of_device_id *id = of_match_device(pwm_of_match, dev);
+
+	return id ? id->data : NULL;
+}
+
+static struct pwm_device *
+pxa_pwm_of_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
+{
+	struct pwm_device *pwm;
+
+	pwm = pwm_request_from_chip(pc, 0, NULL);
+	if (IS_ERR(pwm))
+		return pwm;
+
+	pwm_set_period(pwm, args->args[0]);
+
+	return pwm;
+}
+
+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;
+	int ret = 0;
+
+	if (IS_ENABLED(CONFIG_OF) && id == NULL)
+		id = pxa_pwm_get_id_dt(&pdev->dev);
+
+	if (id == NULL)
+		return -EINVAL;
+
+	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+	if (pwm == NULL)
+		return -ENOMEM;
+
+	pwm->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(pwm->clk))
+		return PTR_ERR(pwm->clk);
+
+	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;
+
+	if (IS_ENABLED(CONFIG_OF)) {
+		pwm->chip.of_xlate = pxa_pwm_of_xlate;
+		pwm->chip.of_pwm_n_cells = 1;
+	}
+
+	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);
+
+	ret = pwmchip_add(&pwm->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, pwm);
+	return 0;
+}
+
+static int pwm_remove(struct platform_device *pdev)
+{
+	struct pxa_pwm_chip *chip;
+
+	chip = platform_get_drvdata(pdev);
+	if (chip == NULL)
+		return -ENODEV;
+
+	return pwmchip_remove(&chip->chip);
+}
+
+static struct platform_driver pwm_driver = {
+	.driver		= {
+		.name	= "pxa25x-pwm",
+		.of_match_table = pwm_of_match,
+	},
+	.probe		= pwm_probe,
+	.remove		= pwm_remove,
+	.id_table	= pwm_id_table,
+};
+
+module_platform_driver(pwm_driver);
+
+MODULE_LICENSE("GPL v2");