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Release 4.14 drivers/pwm/pwm-samsung.c

Directory: drivers/pwm
/*
 * Copyright (c) 2007 Ben Dooks
 * Copyright (c) 2008 Simtec Electronics
 *     Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
 * Copyright (c) 2013 Tomasz Figa <tomasz.figa@gmail.com>
 * Copyright (c) 2017 Samsung Electronics Co., Ltd.
 *
 * PWM driver for Samsung SoCs
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License.
 */

#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/time.h>

/* For struct samsung_timer_variant and samsung_pwm_lock. */
#include <clocksource/samsung_pwm.h>


#define REG_TCFG0			0x00

#define REG_TCFG1			0x04

#define REG_TCON			0x08


#define REG_TCNTB(chan)			(0x0c + ((chan) * 0xc))

#define REG_TCMPB(chan)			(0x10 + ((chan) * 0xc))


#define TCFG0_PRESCALER_MASK		0xff

#define TCFG0_PRESCALER1_SHIFT		8


#define TCFG1_MUX_MASK			0xf

#define TCFG1_SHIFT(chan)		(4 * (chan))

/*
 * Each channel occupies 4 bits in TCON register, but there is a gap of 4
 * bits (one channel) after channel 0, so channels have different numbering
 * when accessing TCON register. See to_tcon_channel() function.
 *
 * In addition, the location of autoreload bit for channel 4 (TCON channel 5)
 * in its set of bits is 2 as opposed to 3 for other channels.
 */

#define TCON_START(chan)		BIT(4 * (chan) + 0)

#define TCON_MANUALUPDATE(chan)		BIT(4 * (chan) + 1)

#define TCON_INVERT(chan)		BIT(4 * (chan) + 2)

#define _TCON_AUTORELOAD(chan)		BIT(4 * (chan) + 3)

#define _TCON_AUTORELOAD4(chan)		BIT(4 * (chan) + 2)

#define TCON_AUTORELOAD(chan)		\
	((chan < 5) ? _TCON_AUTORELOAD(chan) : _TCON_AUTORELOAD4(chan))

/**
 * struct samsung_pwm_channel - private data of PWM channel
 * @period_ns:  current period in nanoseconds programmed to the hardware
 * @duty_ns:    current duty time in nanoseconds programmed to the hardware
 * @tin_ns:     time of one timer tick in nanoseconds with current timer rate
 */

struct samsung_pwm_channel {
	
u32 period_ns;
	
u32 duty_ns;
	
u32 tin_ns;
};

/**
 * struct samsung_pwm_chip - private data of PWM chip
 * @chip:               generic PWM chip
 * @variant:            local copy of hardware variant data
 * @inverter_mask:      inverter status for all channels - one bit per channel
 * @disabled_mask:      disabled status for all channels - one bit per channel
 * @base:               base address of mapped PWM registers
 * @base_clk:           base clock used to drive the timers
 * @tclk0:              external clock 0 (can be ERR_PTR if not present)
 * @tclk1:              external clock 1 (can be ERR_PTR if not present)
 */

struct samsung_pwm_chip {
	
struct pwm_chip chip;
	
struct samsung_pwm_variant variant;
	
u8 inverter_mask;
	
u8 disabled_mask;

	
void __iomem *base;
	
struct clk *base_clk;
	
struct clk *tclk0;
	
struct clk *tclk1;
};

#ifndef CONFIG_CLKSRC_SAMSUNG_PWM
/*
 * PWM block is shared between pwm-samsung and samsung_pwm_timer drivers
 * and some registers need access synchronization. If both drivers are
 * compiled in, the spinlock is defined in the clocksource driver,
 * otherwise following definition is used.
 *
 * Currently we do not need any more complex synchronization method
 * because all the supported SoCs contain only one instance of the PWM
 * IP. Should this change, both drivers will need to be modified to
 * properly synchronize accesses to particular instances.
 */
static DEFINE_SPINLOCK(samsung_pwm_lock);
#endif


static inline struct samsung_pwm_chip *to_samsung_pwm_chip(struct pwm_chip *chip) { return container_of(chip, struct samsung_pwm_chip, chip); }

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static inline unsigned int to_tcon_channel(unsigned int channel) { /* TCON register has a gap of 4 bits (1 channel) after channel 0 */ return (channel == 0) ? 0 : (channel + 1); }

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static void pwm_samsung_set_divisor(struct samsung_pwm_chip *pwm, unsigned int channel, u8 divisor) { u8 shift = TCFG1_SHIFT(channel); unsigned long flags; u32 reg; u8 bits; bits = (fls(divisor) - 1) - pwm->variant.div_base; spin_lock_irqsave(&samsung_pwm_lock, flags); reg = readl(pwm->base + REG_TCFG1); reg &= ~(TCFG1_MUX_MASK << shift); reg |= bits << shift; writel(reg, pwm->base + REG_TCFG1); spin_unlock_irqrestore(&samsung_pwm_lock, flags); }

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static int pwm_samsung_is_tdiv(struct samsung_pwm_chip *chip, unsigned int chan) { struct samsung_pwm_variant *variant = &chip->variant; u32 reg; reg = readl(chip->base + REG_TCFG1); reg >>= TCFG1_SHIFT(chan); reg &= TCFG1_MUX_MASK; return (BIT(reg) & variant->tclk_mask) == 0; }

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static unsigned long pwm_samsung_get_tin_rate(struct samsung_pwm_chip *chip, unsigned int chan) { unsigned long rate; u32 reg; rate = clk_get_rate(chip->base_clk); reg = readl(chip->base + REG_TCFG0); if (chan >= 2) reg >>= TCFG0_PRESCALER1_SHIFT; reg &= TCFG0_PRESCALER_MASK; return rate / (reg + 1); }

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static unsigned long pwm_samsung_calc_tin(struct samsung_pwm_chip *chip, unsigned int chan, unsigned long freq) { struct samsung_pwm_variant *variant = &chip->variant; unsigned long rate; struct clk *clk; u8 div; if (!pwm_samsung_is_tdiv(chip, chan)) { clk = (chan < 2) ? chip->tclk0 : chip->tclk1; if (!IS_ERR(clk)) { rate = clk_get_rate(clk); if (rate) return rate; } dev_warn(chip->chip.dev, "tclk of PWM %d is inoperational, using tdiv\n", chan); } rate = pwm_samsung_get_tin_rate(chip, chan); dev_dbg(chip->chip.dev, "tin parent at %lu\n", rate); /* * Compare minimum PWM frequency that can be achieved with possible * divider settings and choose the lowest divisor that can generate * frequencies lower than requested. */ if (variant->bits < 32) { /* Only for s3c24xx */ for (div = variant->div_base; div < 4; ++div) if ((rate >> (variant->bits + div)) < freq) break; } else { /* * Other variants have enough counter bits to generate any * requested rate, so no need to check higher divisors. */ div = variant->div_base; } pwm_samsung_set_divisor(chip, chan, BIT(div)); return rate >> div; }

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static int pwm_samsung_request(struct pwm_chip *chip, struct pwm_device *pwm) { struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip); struct samsung_pwm_channel *our_chan; if (!(our_chip->variant.output_mask & BIT(pwm->hwpwm))) { dev_warn(chip->dev, "tried to request PWM channel %d without output\n", pwm->hwpwm); return -EINVAL; } our_chan = devm_kzalloc(chip->dev, sizeof(*our_chan), GFP_KERNEL); if (!our_chan) return -ENOMEM; pwm_set_chip_data(pwm, our_chan); return 0; }

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static void pwm_samsung_free(struct pwm_chip *chip, struct pwm_device *pwm) { devm_kfree(chip->dev, pwm_get_chip_data(pwm)); pwm_set_chip_data(pwm, NULL); }

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static int pwm_samsung_enable(struct pwm_chip *chip, struct pwm_device *pwm) { struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip); unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm); unsigned long flags; u32 tcon; spin_lock_irqsave(&samsung_pwm_lock, flags); tcon = readl(our_chip->base + REG_TCON); tcon &= ~TCON_START(tcon_chan); tcon |= TCON_MANUALUPDATE(tcon_chan); writel(tcon, our_chip->base + REG_TCON); tcon &= ~TCON_MANUALUPDATE(tcon_chan); tcon |= TCON_START(tcon_chan) | TCON_AUTORELOAD(tcon_chan); writel(tcon, our_chip->base + REG_TCON); our_chip->disabled_mask &= ~BIT(pwm->hwpwm); spin_unlock_irqrestore(&samsung_pwm_lock, flags); return 0; }

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static void pwm_samsung_disable(struct pwm_chip *chip, struct pwm_device *pwm) { struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip); unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm); unsigned long flags; u32 tcon; spin_lock_irqsave(&samsung_pwm_lock, flags); tcon = readl(our_chip->base + REG_TCON); tcon &= ~TCON_AUTORELOAD(tcon_chan); writel(tcon, our_chip->base + REG_TCON); our_chip->disabled_mask |= BIT(pwm->hwpwm); spin_unlock_irqrestore(&samsung_pwm_lock, flags); }

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static void pwm_samsung_manual_update(struct samsung_pwm_chip *chip, struct pwm_device *pwm) { unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm); u32 tcon; unsigned long flags; spin_lock_irqsave(&samsung_pwm_lock, flags); tcon = readl(chip->base + REG_TCON); tcon |= TCON_MANUALUPDATE(tcon_chan); writel(tcon, chip->base + REG_TCON); tcon &= ~TCON_MANUALUPDATE(tcon_chan); writel(tcon, chip->base + REG_TCON); spin_unlock_irqrestore(&samsung_pwm_lock, flags); }

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static int __pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns, bool force_period) { struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip); struct samsung_pwm_channel *chan = pwm_get_chip_data(pwm); u32 tin_ns = chan->tin_ns, tcnt, tcmp, oldtcmp; /* * We currently avoid using 64bit arithmetic by using the * fact that anything faster than 1Hz is easily representable * by 32bits. */ if (period_ns > NSEC_PER_SEC) return -ERANGE; tcnt = readl(our_chip->base + REG_TCNTB(pwm->hwpwm)); oldtcmp = readl(our_chip->base + REG_TCMPB(pwm->hwpwm)); /* We need tick count for calculation, not last tick. */ ++tcnt; /* Check to see if we are changing the clock rate of the PWM. */ if (chan->period_ns != period_ns || force_period) { unsigned long tin_rate; u32 period; period = NSEC_PER_SEC / period_ns; dev_dbg(our_chip->chip.dev, "duty_ns=%d, period_ns=%d (%u)\n", duty_ns, period_ns, period); tin_rate = pwm_samsung_calc_tin(our_chip, pwm->hwpwm, period); dev_dbg(our_chip->chip.dev, "tin_rate=%lu\n", tin_rate); tin_ns = NSEC_PER_SEC / tin_rate; tcnt = period_ns / tin_ns; } /* Period is too short. */ if (tcnt <= 1) return -ERANGE; /* Note that counters count down. */ tcmp = duty_ns / tin_ns; /* 0% duty is not available */ if (!tcmp) ++tcmp; tcmp = tcnt - tcmp; /* Decrement to get tick numbers, instead of tick counts. */ --tcnt; /* -1UL will give 100% duty. */ --tcmp; dev_dbg(our_chip->chip.dev, "tin_ns=%u, tcmp=%u/%u\n", tin_ns, tcmp, tcnt); /* Update PWM registers. */ writel(tcnt, our_chip->base + REG_TCNTB(pwm->hwpwm)); writel(tcmp, our_chip->base + REG_TCMPB(pwm->hwpwm)); /* * In case the PWM is currently at 100% duty cycle, force a manual * update to prevent the signal staying high if the PWM is disabled * shortly afer this update (before it autoreloaded the new values). */ if (oldtcmp == (u32) -1) { dev_dbg(our_chip->chip.dev, "Forcing manual update"); pwm_samsung_manual_update(our_chip, pwm); } chan->period_ns = period_ns; chan->tin_ns = tin_ns; chan->duty_ns = duty_ns; return 0; }

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static int pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns) { return __pwm_samsung_config(chip, pwm, duty_ns, period_ns, false); }

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static void pwm_samsung_set_invert(struct samsung_pwm_chip *chip, unsigned int channel, bool invert) { unsigned int tcon_chan = to_tcon_channel(channel); unsigned long flags; u32 tcon; spin_lock_irqsave(&samsung_pwm_lock, flags); tcon = readl(chip->base + REG_TCON); if (invert) { chip->inverter_mask |= BIT(channel); tcon |= TCON_INVERT(tcon_chan); } else { chip->inverter_mask &= ~BIT(channel); tcon &= ~TCON_INVERT(tcon_chan); } writel(tcon, chip->base + REG_TCON); spin_unlock_irqrestore(&samsung_pwm_lock, flags); }

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static int pwm_samsung_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, enum pwm_polarity polarity) { struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip); bool invert = (polarity == PWM_POLARITY_NORMAL); /* Inverted means normal in the hardware. */ pwm_samsung_set_invert(our_chip, pwm->hwpwm, invert); return 0; }

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static const struct pwm_ops pwm_samsung_ops = { .request = pwm_samsung_request, .free = pwm_samsung_free, .enable = pwm_samsung_enable, .disable = pwm_samsung_disable, .config = pwm_samsung_config, .set_polarity = pwm_samsung_set_polarity, .owner = THIS_MODULE, }; #ifdef CONFIG_OF static const struct samsung_pwm_variant s3c24xx_variant = { .bits = 16, .div_base = 1, .has_tint_cstat = false, .tclk_mask = BIT(4), }; static const struct samsung_pwm_variant s3c64xx_variant = { .bits = 32, .div_base = 0, .has_tint_cstat = true, .tclk_mask = BIT(7) | BIT(6) | BIT(5), }; static const struct samsung_pwm_variant s5p64x0_variant = { .bits = 32, .div_base = 0, .has_tint_cstat = true, .tclk_mask = 0, }; static const struct samsung_pwm_variant s5pc100_variant = { .bits = 32, .div_base = 0, .has_tint_cstat = true, .tclk_mask = BIT(5), }; static const struct of_device_id samsung_pwm_matches[] = { { .compatible = "samsung,s3c2410-pwm", .data = &s3c24xx_variant }, { .compatible = "samsung,s3c6400-pwm", .data = &s3c64xx_variant }, { .compatible = "samsung,s5p6440-pwm", .data = &s5p64x0_variant }, { .compatible = "samsung,s5pc100-pwm", .data = &s5pc100_variant }, { .compatible = "samsung,exynos4210-pwm", .data = &s5p64x0_variant }, {}, }; MODULE_DEVICE_TABLE(of, samsung_pwm_matches);
static int pwm_samsung_parse_dt(struct samsung_pwm_chip *chip) { struct device_node *np = chip->chip.dev->of_node; const struct of_device_id *match; struct property *prop; const __be32 *cur; u32 val; match = of_match_node(samsung_pwm_matches, np); if (!match) return -ENODEV; memcpy(&chip->variant, match->data, sizeof(chip->variant)); of_property_for_each_u32(np, "samsung,pwm-outputs", prop, cur, val) { if (val >= SAMSUNG_PWM_NUM) { dev_err(chip->chip.dev, "%s: invalid channel index in samsung,pwm-outputs property\n", __func__); continue; } chip->variant.output_mask |= BIT(val); } return 0; }

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#else
static int pwm_samsung_parse_dt(struct samsung_pwm_chip *chip) { return -ENODEV; }

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#endif
static int pwm_samsung_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct samsung_pwm_chip *chip; struct resource *res; unsigned int chan; int ret; chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); if (chip == NULL) return -ENOMEM; chip->chip.dev = &pdev->dev; chip->chip.ops = &pwm_samsung_ops; chip->chip.base = -1; chip->chip.npwm = SAMSUNG_PWM_NUM; chip->inverter_mask = BIT(SAMSUNG_PWM_NUM) - 1; if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) { ret = pwm_samsung_parse_dt(chip); if (ret) return ret; chip->chip.of_xlate = of_pwm_xlate_with_flags; chip->chip.of_pwm_n_cells = 3; } else { if (!pdev->dev.platform_data) { dev_err(&pdev->dev, "no platform data specified\n"); return -EINVAL; } memcpy(&chip->variant, pdev->dev.platform_data, sizeof(chip->variant)); } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); chip->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(chip->base)) return PTR_ERR(chip->base); chip->base_clk = devm_clk_get(&pdev->dev, "timers"); if (IS_ERR(chip->base_clk)) { dev_err(dev, "failed to get timer base clk\n"); return PTR_ERR(chip->base_clk); } ret = clk_prepare_enable(chip->base_clk); if (ret < 0) { dev_err(dev, "failed to enable base clock\n"); return ret; } for (chan = 0; chan < SAMSUNG_PWM_NUM; ++chan) if (chip->variant.output_mask & BIT(chan)) pwm_samsung_set_invert(chip, chan, true); /* Following clocks are optional. */ chip->tclk0 = devm_clk_get(&pdev->dev, "pwm-tclk0"); chip->tclk1 = devm_clk_get(&pdev->dev, "pwm-tclk1"); platform_set_drvdata(pdev, chip); ret = pwmchip_add(&chip->chip); if (ret < 0) { dev_err(dev, "failed to register PWM chip\n"); clk_disable_unprepare(chip->base_clk); return ret; } dev_dbg(dev, "base_clk at %lu, tclk0 at %lu, tclk1 at %lu\n", clk_get_rate(chip->base_clk), !IS_ERR(chip->tclk0) ? clk_get_rate(chip->tclk0) : 0, !IS_ERR(chip->tclk1) ? clk_get_rate(chip->tclk1) : 0); return 0; }

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static int pwm_samsung_remove(struct platform_device *pdev) { struct samsung_pwm_chip *chip = platform_get_drvdata(pdev); int ret; ret = pwmchip_remove(&chip->chip); if (ret < 0) return ret; clk_disable_unprepare(chip->base_clk); return 0; }

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#ifdef CONFIG_PM_SLEEP
static int pwm_samsung_resume(struct device *dev) { struct samsung_pwm_chip *our_chip = dev_get_drvdata(dev); struct pwm_chip *chip = &our_chip->chip; unsigned int i; for (i = 0; i < SAMSUNG_PWM_NUM; i++) { struct pwm_device *pwm = &chip->pwms[i]; struct samsung_pwm_channel *chan = pwm_get_chip_data(pwm); if (!chan) continue; if (our_chip->variant.output_mask & BIT(i)) pwm_samsung_set_invert(our_chip, i, our_chip->inverter_mask & BIT(i)); if (chan->period_ns) { __pwm_samsung_config(chip, pwm, chan->duty_ns, chan->period_ns, true); /* needed to make PWM disable work on Odroid-XU3 */ pwm_samsung_manual_update(our_chip, pwm); } if (our_chip->disabled_mask & BIT(i)) pwm_samsung_disable(chip, pwm); else pwm_samsung_enable(chip, pwm); } return 0; }

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#endif static SIMPLE_DEV_PM_OPS(pwm_samsung_pm_ops, NULL, pwm_samsung_resume); static struct platform_driver pwm_samsung_driver = { .driver = { .name = "samsung-pwm", .pm = &pwm_samsung_pm_ops, .of_match_table = of_match_ptr(samsung_pwm_matches), }, .probe = pwm_samsung_probe, .remove = pwm_samsung_remove, }; module_platform_driver(pwm_samsung_driver); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Tomasz Figa <tomasz.figa@gmail.com>"); MODULE_ALIAS("platform:samsung-pwm");

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Directory: drivers/pwm
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