diff options
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/pwm/Makefile | 1 | ||||
| -rw-r--r-- | drivers/pwm/pwm-dwc.c | 319 |
3 files changed, 329 insertions, 0 deletions
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index e019db18b6ca..d2c199b93585 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -161,6 +161,15 @@ config PWM_CROS_EC PWM driver for exposing a PWM attached to the ChromeOS Embedded Controller. +config PWM_DWC + tristate "DesignWare PWM Controller" + depends on PCI + help + PWM driver for Synopsys DWC PWM Controller attached to a PCI bus. + + To compile this driver as a module, choose M here: the module + will be called pwm-dwc. + config PWM_EP93XX tristate "Cirrus Logic EP93xx PWM support" depends on ARCH_EP93XX || COMPILE_TEST diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 3339f382986d..2dd881665698 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -13,6 +13,7 @@ obj-$(CONFIG_PWM_BRCMSTB) += pwm-brcmstb.o obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o obj-$(CONFIG_PWM_CRC) += pwm-crc.o obj-$(CONFIG_PWM_CROS_EC) += pwm-cros-ec.o +obj-$(CONFIG_PWM_DWC) += pwm-dwc.o obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o obj-$(CONFIG_PWM_HIBVT) += pwm-hibvt.o diff --git a/drivers/pwm/pwm-dwc.c b/drivers/pwm/pwm-dwc.c new file mode 100644 index 000000000000..f6c98e0d57c2 --- /dev/null +++ b/drivers/pwm/pwm-dwc.c @@ -0,0 +1,319 @@ +// 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"); |