--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DesignWare PWM Controller driver
+ *
+ * Copyright (C) 2018-2020 Intel Corporation
+ *
+ * Author: Felipe Balbi (Intel)
+ * Author: Jarkko Nikula <jarkko.nikula@linux.intel.com>
+ * Author: Raymond Tan <raymond.tan@intel.com>
+ *
+ * Limitations:
+ * - The hardware cannot generate a 0 % or 100 % duty cycle. Both high and low
+ * periods are one or more input clock periods long.
+ */
+
+#include <linux/bitops.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+
+#define DWC_TIM_LD_CNT(n) ((n) * 0x14)
+#define DWC_TIM_LD_CNT2(n) (((n) * 4) + 0xb0)
+#define DWC_TIM_CUR_VAL(n) (((n) * 0x14) + 0x04)
+#define DWC_TIM_CTRL(n) (((n) * 0x14) + 0x08)
+#define DWC_TIM_EOI(n) (((n) * 0x14) + 0x0c)
+#define DWC_TIM_INT_STS(n) (((n) * 0x14) + 0x10)
+
+#define DWC_TIMERS_INT_STS 0xa0
+#define DWC_TIMERS_EOI 0xa4
+#define DWC_TIMERS_RAW_INT_STS 0xa8
+#define DWC_TIMERS_COMP_VERSION 0xac
+
+#define DWC_TIMERS_TOTAL 8
+#define DWC_CLK_PERIOD_NS 10
+
+/* Timer Control Register */
+#define DWC_TIM_CTRL_EN BIT(0)
+#define DWC_TIM_CTRL_MODE BIT(1)
+#define DWC_TIM_CTRL_MODE_FREE (0 << 1)
+#define DWC_TIM_CTRL_MODE_USER (1 << 1)
+#define DWC_TIM_CTRL_INT_MASK BIT(2)
+#define DWC_TIM_CTRL_PWM BIT(3)
+
+struct dwc_pwm_ctx {
+ u32 cnt;
+ u32 cnt2;
+ u32 ctrl;
+};
+
+struct dwc_pwm {
+ struct pwm_chip chip;
+ void __iomem *base;
+ struct dwc_pwm_ctx ctx[DWC_TIMERS_TOTAL];
+};
+#define to_dwc_pwm(p) (container_of((p), struct dwc_pwm, chip))
+
+static inline u32 dwc_pwm_readl(struct dwc_pwm *dwc, u32 offset)
+{
+ return readl(dwc->base + offset);
+}
+
+static inline void dwc_pwm_writel(struct dwc_pwm *dwc, u32 value, u32 offset)
+{
+ writel(value, dwc->base + offset);
+}
+
+static void __dwc_pwm_set_enable(struct dwc_pwm *dwc, int pwm, int enabled)
+{
+ u32 reg;
+
+ reg = dwc_pwm_readl(dwc, DWC_TIM_CTRL(pwm));
+
+ if (enabled)
+ reg |= DWC_TIM_CTRL_EN;
+ else
+ reg &= ~DWC_TIM_CTRL_EN;
+
+ dwc_pwm_writel(dwc, reg, DWC_TIM_CTRL(pwm));
+}
+
+static int __dwc_pwm_configure_timer(struct dwc_pwm *dwc,
+ struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ u64 tmp;
+ u32 ctrl;
+ u32 high;
+ u32 low;
+
+ /*
+ * Calculate width of low and high period in terms of input clock
+ * periods and check are the result within HW limits between 1 and
+ * 2^32 periods.
+ */
+ tmp = DIV_ROUND_CLOSEST_ULL(state->duty_cycle, DWC_CLK_PERIOD_NS);
+ if (tmp < 1 || tmp > (1ULL << 32))
+ return -ERANGE;
+ low = tmp - 1;
+
+ tmp = DIV_ROUND_CLOSEST_ULL(state->period - state->duty_cycle,
+ DWC_CLK_PERIOD_NS);
+ if (tmp < 1 || tmp > (1ULL << 32))
+ return -ERANGE;
+ high = tmp - 1;
+
+ /*
+ * Specification says timer usage flow is to disable timer, then
+ * program it followed by enable. It also says Load Count is loaded
+ * into timer after it is enabled - either after a disable or
+ * a reset. Based on measurements it happens also without disable
+ * whenever Load Count is updated. But follow the specification.
+ */
+ __dwc_pwm_set_enable(dwc, pwm->hwpwm, false);
+
+ /*
+ * Write Load Count and Load Count 2 registers. Former defines the
+ * width of low period and latter the width of high period in terms
+ * multiple of input clock periods:
+ * Width = ((Count + 1) * input clock period).
+ */
+ dwc_pwm_writel(dwc, low, DWC_TIM_LD_CNT(pwm->hwpwm));
+ dwc_pwm_writel(dwc, high, DWC_TIM_LD_CNT2(pwm->hwpwm));
+
+ /*
+ * Set user-defined mode, timer reloads from Load Count registers
+ * when it counts down to 0.
+ * Set PWM mode, it makes output to toggle and width of low and high
+ * periods are set by Load Count registers.
+ */
+ ctrl = DWC_TIM_CTRL_MODE_USER | DWC_TIM_CTRL_PWM;
+ dwc_pwm_writel(dwc, ctrl, DWC_TIM_CTRL(pwm->hwpwm));
+
+ /*
+ * Enable timer. Output starts from low period.
+ */
+ __dwc_pwm_set_enable(dwc, pwm->hwpwm, state->enabled);
+
+ return 0;
+}
+
+static int dwc_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct dwc_pwm *dwc = to_dwc_pwm(chip);
+
+ if (state->polarity != PWM_POLARITY_INVERSED)
+ return -EINVAL;
+
+ if (state->enabled) {
+ if (!pwm->state.enabled)
+ pm_runtime_get_sync(chip->dev);
+ return __dwc_pwm_configure_timer(dwc, pwm, state);
+ } else {
+ if (pwm->state.enabled) {
+ __dwc_pwm_set_enable(dwc, pwm->hwpwm, false);
+ pm_runtime_put_sync(chip->dev);
+ }
+ }
+
+ return 0;
+}
+
+static void dwc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct dwc_pwm *dwc = to_dwc_pwm(chip);
+ u64 duty, period;
+
+ pm_runtime_get_sync(chip->dev);
+
+ state->enabled = !!(dwc_pwm_readl(dwc,
+ DWC_TIM_CTRL(pwm->hwpwm)) & DWC_TIM_CTRL_EN);
+
+ duty = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT(pwm->hwpwm));
+ duty += 1;
+ duty *= DWC_CLK_PERIOD_NS;
+ state->duty_cycle = duty;
+
+ period = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT2(pwm->hwpwm));
+ period += 1;
+ period *= DWC_CLK_PERIOD_NS;
+ period += duty;
+ state->period = period;
+
+ state->polarity = PWM_POLARITY_INVERSED;
+
+ pm_runtime_put_sync(chip->dev);
+}
+
+static const struct pwm_ops dwc_pwm_ops = {
+ .apply = dwc_pwm_apply,
+ .get_state = dwc_pwm_get_state,
+ .owner = THIS_MODULE,
+};
+
+static int dwc_pwm_probe(struct pci_dev *pci, const struct pci_device_id *id)
+{
+ struct device *dev = &pci->dev;
+ struct dwc_pwm *dwc;
+ int ret;
+
+ dwc = devm_kzalloc(&pci->dev, sizeof(*dwc), GFP_KERNEL);
+ if (!dwc)
+ return -ENOMEM;
+
+ ret = pcim_enable_device(pci);
+ if (ret) {
+ dev_err(&pci->dev,
+ "Failed to enable device (%pe)\n", ERR_PTR(ret));
+ return ret;
+ }
+
+ pci_set_master(pci);
+
+ ret = pcim_iomap_regions(pci, BIT(0), pci_name(pci));
+ if (ret) {
+ dev_err(&pci->dev,
+ "Failed to iomap PCI BAR (%pe)\n", ERR_PTR(ret));
+ return ret;
+ }
+
+ dwc->base = pcim_iomap_table(pci)[0];
+ if (!dwc->base) {
+ dev_err(&pci->dev, "Base address missing\n");
+ return -ENOMEM;
+ }
+
+ pci_set_drvdata(pci, dwc);
+
+ dwc->chip.dev = dev;
+ dwc->chip.ops = &dwc_pwm_ops;
+ dwc->chip.npwm = DWC_TIMERS_TOTAL;
+ dwc->chip.base = -1;
+
+ ret = pwmchip_add(&dwc->chip);
+ if (ret)
+ return ret;
+
+ pm_runtime_put(dev);
+ pm_runtime_allow(dev);
+
+ return 0;
+}
+
+static void dwc_pwm_remove(struct pci_dev *pci)
+{
+ struct dwc_pwm *dwc = pci_get_drvdata(pci);
+
+ pm_runtime_forbid(&pci->dev);
+ pm_runtime_get_noresume(&pci->dev);
+
+ pwmchip_remove(&dwc->chip);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int dwc_pwm_suspend(struct device *dev)
+{
+ struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
+ struct dwc_pwm *dwc = pci_get_drvdata(pdev);
+ int i;
+
+ for (i = 0; i < DWC_TIMERS_TOTAL; i++) {
+ if (dwc->chip.pwms[i].state.enabled) {
+ dev_err(dev, "PWM %u in use by consumer (%s)\n",
+ i, dwc->chip.pwms[i].label);
+ return -EBUSY;
+ }
+ dwc->ctx[i].cnt = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT(i));
+ dwc->ctx[i].cnt2 = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT2(i));
+ dwc->ctx[i].ctrl = dwc_pwm_readl(dwc, DWC_TIM_CTRL(i));
+ }
+
+ return 0;
+}
+
+static int dwc_pwm_resume(struct device *dev)
+{
+ struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
+ struct dwc_pwm *dwc = pci_get_drvdata(pdev);
+ int i;
+
+ for (i = 0; i < DWC_TIMERS_TOTAL; i++) {
+ dwc_pwm_writel(dwc, dwc->ctx[i].cnt, DWC_TIM_LD_CNT(i));
+ dwc_pwm_writel(dwc, dwc->ctx[i].cnt2, DWC_TIM_LD_CNT2(i));
+ dwc_pwm_writel(dwc, dwc->ctx[i].ctrl, DWC_TIM_CTRL(i));
+ }
+
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(dwc_pwm_pm_ops, dwc_pwm_suspend, dwc_pwm_resume);
+
+static const struct pci_device_id dwc_pwm_id_table[] = {
+ { PCI_VDEVICE(INTEL, 0x4bb7) }, /* Elkhart Lake */
+ { } /* Terminating Entry */
+};
+MODULE_DEVICE_TABLE(pci, dwc_pwm_id_table);
+
+static struct pci_driver dwc_pwm_driver = {
+ .name = "pwm-dwc",
+ .probe = dwc_pwm_probe,
+ .remove = dwc_pwm_remove,
+ .id_table = dwc_pwm_id_table,
+ .driver = {
+ .pm = &dwc_pwm_pm_ops,
+ },
+};
+
+module_pci_driver(dwc_pwm_driver);
+
+MODULE_AUTHOR("Felipe Balbi (Intel)");
+MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@linux.intel.com>");
+MODULE_AUTHOR("Raymond Tan <raymond.tan@intel.com>");
+MODULE_DESCRIPTION("DesignWare PWM Controller");
+MODULE_LICENSE("GPL");
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