1 files changed, 282 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
new file mode 100644
index 00000000000..44ce6c6103a
--- /dev/null
+++ b/drivers/pwm/pwm-lpss.c
@@ -0,0 +1,282 @@
+/*
+ * Intel Low Power Subsystem PWM controller driver
+ *
+ * Copyright (C) 2014, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ * Author: Chew Kean Ho <kean.ho.chew@intel.com>
+ * Author: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
+ * Author: Chew Chiau Ee <chiau.ee.chew@intel.com>
+ * Author: Alan Cox <alan@linux.intel.com>
+ *
+ * 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.
+ */
+
+#include <linux/acpi.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pwm.h>
+#include <linux/platform_device.h>
+#include <linux/pci.h>
+
+static int pci_drv, plat_drv;	/* So we know which drivers registered */
+
+#define PWM				0x00000000
+#define PWM_ENABLE			BIT(31)
+#define PWM_SW_UPDATE			BIT(30)
+#define PWM_BASE_UNIT_SHIFT		8
+#define PWM_BASE_UNIT_MASK		0x00ffff00
+#define PWM_ON_TIME_DIV_MASK		0x000000ff
+#define PWM_DIVISION_CORRECTION		0x2
+#define PWM_LIMIT			(0x8000 + PWM_DIVISION_CORRECTION)
+#define NSECS_PER_SEC			1000000000UL
+
+struct pwm_lpss_chip {
+	struct pwm_chip chip;
+	void __iomem *regs;
+	struct clk *clk;
+	unsigned long clk_rate;
+};
+
+struct pwm_lpss_boardinfo {
+	unsigned long clk_rate;
+};
+
+/* BayTrail */
+static const struct pwm_lpss_boardinfo byt_info = {
+	25000000
+};
+
+static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip)
+{
+	return container_of(chip, struct pwm_lpss_chip, chip);
+}
+
+static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			   int duty_ns, int period_ns)
+{
+	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
+	u8 on_time_div;
+	unsigned long c;
+	unsigned long long base_unit, freq = NSECS_PER_SEC;
+	u32 ctrl;
+
+	do_div(freq, period_ns);
+
+	/* The equation is: base_unit = ((freq / c) * 65536) + correction */
+	base_unit = freq * 65536;
+
+	c = lpwm->clk_rate;
+	if (!c)
+		return -EINVAL;
+
+	do_div(base_unit, c);
+	base_unit += PWM_DIVISION_CORRECTION;
+	if (base_unit > PWM_LIMIT)
+		return -EINVAL;
+
+	if (duty_ns <= 0)
+		duty_ns = 1;
+	on_time_div = 255 - (255 * duty_ns / period_ns);
+
+	ctrl = readl(lpwm->regs + PWM);
+	ctrl &= ~(PWM_BASE_UNIT_MASK | PWM_ON_TIME_DIV_MASK);
+	ctrl |= (u16) base_unit << PWM_BASE_UNIT_SHIFT;
+	ctrl |= on_time_div;
+	/* request PWM to update on next cycle */
+	ctrl |= PWM_SW_UPDATE;
+	writel(ctrl, lpwm->regs + PWM);
+
+	return 0;
+}
+
+static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
+	u32 ctrl;
+	int ret;
+
+	ret = clk_prepare_enable(lpwm->clk);
+	if (ret)
+		return ret;
+
+	ctrl = readl(lpwm->regs + PWM);
+	writel(ctrl | PWM_ENABLE, lpwm->regs + PWM);
+
+	return 0;
+}
+
+static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
+	u32 ctrl;
+
+	ctrl = readl(lpwm->regs + PWM);
+	writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
+
+	clk_disable_unprepare(lpwm->clk);
+}
+
+static const struct pwm_ops pwm_lpss_ops = {
+	.config = pwm_lpss_config,
+	.enable = pwm_lpss_enable,
+	.disable = pwm_lpss_disable,
+	.owner = THIS_MODULE,
+};
+
+static struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev,
+					    struct resource *r,
+					    const struct pwm_lpss_boardinfo *info)
+{
+	struct pwm_lpss_chip *lpwm;
+	int ret;
+
+	lpwm = devm_kzalloc(dev, sizeof(*lpwm), GFP_KERNEL);
+	if (!lpwm)
+		return ERR_PTR(-ENOMEM);
+
+	lpwm->regs = devm_ioremap_resource(dev, r);
+	if (IS_ERR(lpwm->regs))
+		return ERR_CAST(lpwm->regs);
+
+	if (info) {
+		lpwm->clk_rate = info->clk_rate;
+	} else {
+		lpwm->clk = devm_clk_get(dev, NULL);
+		if (IS_ERR(lpwm->clk)) {
+			dev_err(dev, "failed to get PWM clock\n");
+			return ERR_CAST(lpwm->clk);
+		}
+		lpwm->clk_rate = clk_get_rate(lpwm->clk);
+	}
+
+	lpwm->chip.dev = dev;
+	lpwm->chip.ops = &pwm_lpss_ops;
+	lpwm->chip.base = -1;
+	lpwm->chip.npwm = 1;
+
+	ret = pwmchip_add(&lpwm->chip);
+	if (ret) {
+		dev_err(dev, "failed to add PWM chip: %d\n", ret);
+		return ERR_PTR(ret);
+	}
+
+	return lpwm;
+}
+
+static int pwm_lpss_remove(struct pwm_lpss_chip *lpwm)
+{
+	u32 ctrl;
+
+	ctrl = readl(lpwm->regs + PWM);
+	writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
+
+	return pwmchip_remove(&lpwm->chip);
+}
+
+static int pwm_lpss_probe_pci(struct pci_dev *pdev,
+			      const struct pci_device_id *id)
+{
+	const struct pwm_lpss_boardinfo *info;
+	struct pwm_lpss_chip *lpwm;
+	int err;
+
+	err = pci_enable_device(pdev);
+	if (err < 0)
+		return err;
+
+	info = (struct pwm_lpss_boardinfo *)id->driver_data;
+	lpwm = pwm_lpss_probe(&pdev->dev, &pdev->resource[0], info);
+	if (IS_ERR(lpwm))
+		return PTR_ERR(lpwm);
+
+	pci_set_drvdata(pdev, lpwm);
+	return 0;
+}
+
+static void pwm_lpss_remove_pci(struct pci_dev *pdev)
+{
+	struct pwm_lpss_chip *lpwm = pci_get_drvdata(pdev);
+
+	pwm_lpss_remove(lpwm);
+	pci_disable_device(pdev);
+}
+
+static struct pci_device_id pwm_lpss_pci_ids[] = {
+	{ PCI_VDEVICE(INTEL, 0x0f08), (unsigned long)&byt_info},
+	{ PCI_VDEVICE(INTEL, 0x0f09), (unsigned long)&byt_info},
+	{ },
+};
+MODULE_DEVICE_TABLE(pci, pwm_lpss_pci_ids);
+
+static struct pci_driver pwm_lpss_driver_pci = {
+	.name = "pwm-lpss",
+	.id_table = pwm_lpss_pci_ids,
+	.probe = pwm_lpss_probe_pci,
+	.remove = pwm_lpss_remove_pci,
+};
+
+static int pwm_lpss_probe_platform(struct platform_device *pdev)
+{
+	struct pwm_lpss_chip *lpwm;
+	struct resource *r;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+	lpwm = pwm_lpss_probe(&pdev->dev, r, NULL);
+	if (IS_ERR(lpwm))
+		return PTR_ERR(lpwm);
+
+	platform_set_drvdata(pdev, lpwm);
+	return 0;
+}
+
+static int pwm_lpss_remove_platform(struct platform_device *pdev)
+{
+	struct pwm_lpss_chip *lpwm = platform_get_drvdata(pdev);
+
+	return pwm_lpss_remove(lpwm);
+}
+
+static const struct acpi_device_id pwm_lpss_acpi_match[] = {
+	{ "80860F09", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);
+
+static struct platform_driver pwm_lpss_driver_platform = {
+	.driver = {
+		.name = "pwm-lpss",
+		.acpi_match_table = pwm_lpss_acpi_match,
+	},
+	.probe = pwm_lpss_probe_platform,
+	.remove = pwm_lpss_remove_platform,
+};
+
+static int __init pwm_init(void)
+{
+	pci_drv = pci_register_driver(&pwm_lpss_driver_pci);
+	plat_drv = platform_driver_register(&pwm_lpss_driver_platform);
+	if (pci_drv && plat_drv)
+		return pci_drv;
+
+	return 0;
+}
+module_init(pwm_init);
+
+static void __exit pwm_exit(void)
+{
+	if (!pci_drv)
+		pci_unregister_driver(&pwm_lpss_driver_pci);
+	if (!plat_drv)
+		platform_driver_unregister(&pwm_lpss_driver_platform);
+}
+module_exit(pwm_exit);
+
+MODULE_DESCRIPTION("PWM driver for Intel LPSS");
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:pwm-lpss");