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Diffstat (limited to '')
| -rw-r--r-- | drivers/pwm/pwm-samsung.c | 650 |
1 files changed, 650 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-samsung.c b/drivers/pwm/pwm-samsung.c new file mode 100644 index 000000000..87a886f7d --- /dev/null +++ b/drivers/pwm/pwm-samsung.c @@ -0,0 +1,650 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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 + */ + +#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); +} + +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); +} + +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); +} + +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; +} + +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); +} + +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; +} + +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 = kzalloc(sizeof(*our_chan), GFP_KERNEL); + if (!our_chan) + return -ENOMEM; + + pwm_set_chip_data(pwm, our_chan); + + return 0; +} + +static void pwm_samsung_free(struct pwm_chip *chip, struct pwm_device *pwm) +{ + kfree(pwm_get_chip_data(pwm)); +} + +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; +} + +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); +} + +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); +} + +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; +} + +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); +} + +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); +} + +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; +} + +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; +} +#else +static int pwm_samsung_parse_dt(struct samsung_pwm_chip *chip) +{ + return -ENODEV; +} +#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; +} + +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; +} + +#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; +} +#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"); |