![Andy Shevchenko](/assets/img/avatar_default.png)
The PWM LPSS probe drivers just pass a pointer to the exported board info structures to pwm_lpss_probe() based on device PCI or ACPI ID. In order to remove the knowledge of specific devices from library part of the driver and reduce noise in exported namespace just duplicate the board info structures and stop exporting them. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
211 lines
5.5 KiB
C
211 lines
5.5 KiB
C
/*
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* Intel Low Power Subsystem PWM controller driver
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*
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* Copyright (C) 2014, Intel Corporation
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* Author: Mika Westerberg <mika.westerberg@linux.intel.com>
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* Author: Chew Kean Ho <kean.ho.chew@intel.com>
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* Author: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
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* Author: Chew Chiau Ee <chiau.ee.chew@intel.com>
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* Author: Alan Cox <alan@linux.intel.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/delay.h>
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#include <linux/io.h>
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#include <linux/iopoll.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/pm_runtime.h>
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#include <linux/time.h>
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#include "pwm-lpss.h"
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#define PWM 0x00000000
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#define PWM_ENABLE BIT(31)
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#define PWM_SW_UPDATE BIT(30)
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#define PWM_BASE_UNIT_SHIFT 8
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#define PWM_ON_TIME_DIV_MASK 0x000000ff
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/* Size of each PWM register space if multiple */
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#define PWM_SIZE 0x400
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struct pwm_lpss_chip {
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struct pwm_chip chip;
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void __iomem *regs;
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const struct pwm_lpss_boardinfo *info;
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};
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static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip)
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{
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return container_of(chip, struct pwm_lpss_chip, chip);
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}
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static inline u32 pwm_lpss_read(const struct pwm_device *pwm)
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{
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struct pwm_lpss_chip *lpwm = to_lpwm(pwm->chip);
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return readl(lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM);
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}
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static inline void pwm_lpss_write(const struct pwm_device *pwm, u32 value)
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{
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struct pwm_lpss_chip *lpwm = to_lpwm(pwm->chip);
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writel(value, lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM);
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}
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static int pwm_lpss_update(struct pwm_device *pwm)
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{
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struct pwm_lpss_chip *lpwm = to_lpwm(pwm->chip);
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const void __iomem *addr = lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM;
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const unsigned int ms = 500 * USEC_PER_MSEC;
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u32 val;
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int err;
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pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_SW_UPDATE);
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/*
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* PWM Configuration register has SW_UPDATE bit that is set when a new
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* configuration is written to the register. The bit is automatically
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* cleared at the start of the next output cycle by the IP block.
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*
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* If one writes a new configuration to the register while it still has
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* the bit enabled, PWM may freeze. That is, while one can still write
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* to the register, it won't have an effect. Thus, we try to sleep long
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* enough that the bit gets cleared and make sure the bit is not
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* enabled while we update the configuration.
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*/
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err = readl_poll_timeout(addr, val, !(val & PWM_SW_UPDATE), 40, ms);
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if (err)
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dev_err(pwm->chip->dev, "PWM_SW_UPDATE was not cleared\n");
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return err;
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}
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static inline int pwm_lpss_is_updating(struct pwm_device *pwm)
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{
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return (pwm_lpss_read(pwm) & PWM_SW_UPDATE) ? -EBUSY : 0;
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}
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static void pwm_lpss_prepare(struct pwm_lpss_chip *lpwm, struct pwm_device *pwm,
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int duty_ns, int period_ns)
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{
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unsigned long long on_time_div;
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unsigned long c = lpwm->info->clk_rate, base_unit_range;
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unsigned long long base_unit, freq = NSEC_PER_SEC;
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u32 ctrl;
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do_div(freq, period_ns);
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/*
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* The equation is:
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* base_unit = round(base_unit_range * freq / c)
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*/
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base_unit_range = BIT(lpwm->info->base_unit_bits) - 1;
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freq *= base_unit_range;
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base_unit = DIV_ROUND_CLOSEST_ULL(freq, c);
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on_time_div = 255ULL * duty_ns;
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do_div(on_time_div, period_ns);
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on_time_div = 255ULL - on_time_div;
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ctrl = pwm_lpss_read(pwm);
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ctrl &= ~PWM_ON_TIME_DIV_MASK;
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ctrl &= ~(base_unit_range << PWM_BASE_UNIT_SHIFT);
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base_unit &= base_unit_range;
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ctrl |= (u32) base_unit << PWM_BASE_UNIT_SHIFT;
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ctrl |= on_time_div;
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pwm_lpss_write(pwm, ctrl);
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}
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static int pwm_lpss_apply(struct pwm_chip *chip, struct pwm_device *pwm,
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struct pwm_state *state)
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{
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struct pwm_lpss_chip *lpwm = to_lpwm(chip);
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int ret;
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if (state->enabled) {
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if (!pwm_is_enabled(pwm)) {
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pm_runtime_get_sync(chip->dev);
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ret = pwm_lpss_is_updating(pwm);
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if (ret) {
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pm_runtime_put(chip->dev);
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return ret;
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}
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pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period);
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ret = pwm_lpss_update(pwm);
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if (ret) {
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pm_runtime_put(chip->dev);
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return ret;
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}
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pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_ENABLE);
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} else {
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ret = pwm_lpss_is_updating(pwm);
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if (ret)
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return ret;
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pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period);
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return pwm_lpss_update(pwm);
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}
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} else if (pwm_is_enabled(pwm)) {
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pwm_lpss_write(pwm, pwm_lpss_read(pwm) & ~PWM_ENABLE);
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pm_runtime_put(chip->dev);
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}
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return 0;
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}
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static const struct pwm_ops pwm_lpss_ops = {
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.apply = pwm_lpss_apply,
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.owner = THIS_MODULE,
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};
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struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r,
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const struct pwm_lpss_boardinfo *info)
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{
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struct pwm_lpss_chip *lpwm;
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unsigned long c;
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int ret;
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lpwm = devm_kzalloc(dev, sizeof(*lpwm), GFP_KERNEL);
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if (!lpwm)
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return ERR_PTR(-ENOMEM);
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lpwm->regs = devm_ioremap_resource(dev, r);
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if (IS_ERR(lpwm->regs))
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return ERR_CAST(lpwm->regs);
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lpwm->info = info;
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c = lpwm->info->clk_rate;
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if (!c)
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return ERR_PTR(-EINVAL);
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lpwm->chip.dev = dev;
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lpwm->chip.ops = &pwm_lpss_ops;
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lpwm->chip.base = -1;
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lpwm->chip.npwm = info->npwm;
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ret = pwmchip_add(&lpwm->chip);
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if (ret) {
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dev_err(dev, "failed to add PWM chip: %d\n", ret);
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return ERR_PTR(ret);
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}
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return lpwm;
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}
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EXPORT_SYMBOL_GPL(pwm_lpss_probe);
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int pwm_lpss_remove(struct pwm_lpss_chip *lpwm)
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{
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return pwmchip_remove(&lpwm->chip);
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}
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EXPORT_SYMBOL_GPL(pwm_lpss_remove);
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MODULE_DESCRIPTION("PWM driver for Intel LPSS");
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MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
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MODULE_LICENSE("GPL v2");
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