This patch introduces new Samsung PWM driver, which uses Samsung
PWM/timer master driver to control shared parts of the hardware.
Signed-off-by: Tomasz Figa <tomasz.figa@xxxxxxxxx>
---
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-samsung.c | 528 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 529 insertions(+)
create mode 100644 drivers/pwm/pwm-samsung.c
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 229a599..833c3ac 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_PWM_MXS) += pwm-mxs.o
obj-$(CONFIG_PWM_PUV3) += pwm-puv3.o
obj-$(CONFIG_PWM_PXA) += pwm-pxa.o
obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung-legacy.o
+obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o
obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o
obj-$(CONFIG_PWM_TIECAP) += pwm-tiecap.o
diff --git a/drivers/pwm/pwm-samsung.c b/drivers/pwm/pwm-samsung.c
new file mode 100644
index 0000000..61bed3d
--- /dev/null
+++ b/drivers/pwm/pwm-samsung.c
@@ -0,0 +1,528 @@
+/* drivers/pwm/pwm-samsung.c
+ *
+ * Copyright (c) 2007 Ben Dooks
+ * Copyright (c) 2008 Simtec Electronics
+ * Ben Dooks <ben@xxxxxxxxxxxx>, <ben-linux@xxxxxxxxx>
+ * Copyright (c) 2013 Tomasz Figa <tomasz.figa@xxxxxxxxx>
+ *
+ * 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/clk.h>
+#include <linux/export.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/time.h>
+
+#include <clocksource/samsung_pwm.h>
+
+#define REG_TCFG0 0x00
+#define REG_TCFG1 0x04
+#define REG_TCON 0x08
+
+#define REG_TCNTB(tmr) (0x0c + ((tmr) * 0xc))
+#define REG_TCMPB(tmr) (0x10 + ((tmr) * 0xc))
+
+#define TCFG0_PRESCALER_MASK 0xff
+#define TCFG0_PRESCALER1_SHIFT 8
+
+#define TCFG1_MUX_MASK 0xf
+#define TCFG1_SHIFT(x) ((x) * 4)
+
+#define TCON_START(chan) (1 << (4 * (chan) + 0))
+#define TCON_MANUALUPDATE(chan) (1 << (4 * (chan) + 1))
+#define TCON_INVERT(chan) (1 << (4 * (chan) + 2))
+#define TCON_AUTORELOAD(chan) (1 << (4 * (chan) + 3))
+
+struct samsung_pwm_channel {
+ unsigned long period_ns;
+ unsigned long duty_ns;
+ unsigned long tin_ns;
+};
+
+struct samsung_pwm_chip {
+ struct pwm_chip chip;
+ struct samsung_pwm_variant variant;
+ struct samsung_pwm_channel channels[SAMSUNG_PWM_NUM];
+
+ void __iomem *base;
+ struct clk *base_clk;
+ struct clk *tclk0;
+ struct clk *tclk1;
+};
+#define to_samsung_pwm_chip(chip) \
+ container_of(chip, struct samsung_pwm_chip, chip)
+
+#ifndef CONFIG_CLKSRC_SAMSUNG_PWM
+static DEFINE_SPINLOCK(samsung_pwm_lock);
+#endif
+
+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 inline 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 ((1 << 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;
+ unsigned int div;
+ struct clk *clk;
+
+ 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.
+ */
+ for (div = variant->div_base; div < 4; ++div)
+ if ((rate >> (variant->bits + div)) < freq)
+ break;
+
+ pwm_samsung_set_divisor(chip, chan, 1 << 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);
+
+ if (our_chip->variant.output_mask & (1 << pwm->hwpwm))
+ return 0;
+
+ dev_warn(our_chip->chip.dev,
+ "tried to request PWM channel %d without output\n",
+ pwm->hwpwm);
+
+ return -EINVAL;
+}
+
+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 channel = pwm->hwpwm;
+ unsigned long tcon;
+ unsigned long flags;
+
+ if (channel > 0)
+ ++channel;
+
+ spin_lock_irqsave(&samsung_pwm_lock, flags);
+
+ tcon = __raw_readl(our_chip->base + REG_TCON);
+
+ tcon &= ~TCON_MANUALUPDATE(channel);
+ tcon |= TCON_START(channel) | TCON_AUTORELOAD(channel);
+
+ __raw_writel(tcon, our_chip->base + REG_TCON);
+
+ 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 channel = pwm->hwpwm;
+ unsigned long tcon;
+ unsigned long flags;
+
+ if (channel > 0)
+ ++channel;
+
+ spin_lock_irqsave(&samsung_pwm_lock, flags);
+
+ tcon = __raw_readl(our_chip->base + REG_TCON);
+ tcon &= ~TCON_AUTORELOAD(channel);
+ __raw_writel(tcon, our_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)
+{
+ struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
+ struct samsung_pwm_channel *chan = &our_chip->channels[pwm->hwpwm];
+ unsigned long tin_ns = chan->tin_ns;
+ unsigned int tcon_chan = pwm->hwpwm;
+ unsigned long tin_rate;
+ unsigned long period;
+ unsigned long flags;
+ unsigned long tcnt;
+ long tcmp;
+ u32 tcon;
+
+ /* 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 || duty_ns > NSEC_PER_SEC)
+ return -ERANGE;
+
+ if (period_ns == chan->period_ns && duty_ns == chan->duty_ns)
+ return 0;
+
+ /* The TCMP and TCNT can be read without a lock, they're not
+ * shared between the timers. */
+ tcmp = readl(our_chip->base + REG_TCMPB(pwm->hwpwm));
+ tcnt = readl(our_chip->base + REG_TCNTB(pwm->hwpwm));
+
+ period = NSEC_PER_SEC / period_ns;
+
+ dev_dbg(our_chip->chip.dev, "duty_ns=%d, period_ns=%d (%lu)\n",
+ duty_ns, period_ns, period);
+
+ /* Check to see if we are changing the clock rate of the PWM */
+ if (chan->period_ns != period_ns) {
+ tin_rate = pwm_samsung_calc_tin(our_chip, pwm->hwpwm, period);
+
+ chan->period_ns = period_ns;
+
+ dev_dbg(our_chip->chip.dev, "tin_rate=%lu\n", tin_rate);
+
+ tin_ns = NSEC_PER_SEC / tin_rate;
+ tcnt = period_ns / tin_ns;
+
+ chan->tin_ns = tin_ns;
+ }
+
+ /* Note, counters count down */
+ tcmp = duty_ns / tin_ns;
+ tcmp = tcnt - tcmp;
+
+ /* the pwm hw only checks the compare register after a decrement,
+ so the pin never toggles if tcmp = tcnt */
+ if (tcmp == tcnt)
+ tcmp--;
+
+ dev_dbg(our_chip->chip.dev, "tin_ns=%lu, tcmp=%ld/%lu\n",
+ tin_ns, tcmp, tcnt);
+
+ if (tcmp < 0)
+ tcmp = 0;
+
+ /* Update the PWM register block. */
+ if (tcon_chan > 0)
+ ++tcon_chan;
+
+ spin_lock_irqsave(&samsung_pwm_lock, flags);
+
+ tcon = __raw_readl(our_chip->base + REG_TCON);
+
+ tcnt--;
+
+ tcon &= ~(TCON_START(tcon_chan) | TCON_AUTORELOAD(tcon_chan));
+ tcon |= TCON_MANUALUPDATE(tcon_chan);
+
+ __raw_writel(tcnt, our_chip->base + REG_TCNTB(pwm->hwpwm));
+ __raw_writel(tcmp, our_chip->base + REG_TCMPB(pwm->hwpwm));
+ __raw_writel(tcon, our_chip->base + REG_TCON);
+
+ spin_unlock_irqrestore(&samsung_pwm_lock, flags);
+
+ return 0;
+}
+
+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);
+ unsigned int channel = pwm->hwpwm;
+ unsigned long flags;
+ u32 tcon;
+
+ if (channel > 0)
+ ++channel;
+
+ spin_lock_irqsave(&samsung_pwm_lock, flags);
+
+ tcon = __raw_readl(our_chip->base + REG_TCON);
+
+ /* Invert in hardware means normal polarity of PWM core */
+ if (polarity == PWM_POLARITY_NORMAL)
+ tcon |= TCON_INVERT(channel);
+ else
+ tcon &= ~TCON_INVERT(channel);
+
+ __raw_writel(tcon, our_chip->base + REG_TCON);
+
+ spin_unlock_irqrestore(&samsung_pwm_lock, flags);
+
+ return 0;
+}
+
+static struct pwm_ops pwm_samsung_ops = {
+ .request = pwm_samsung_request,
+ .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 = (1 << 4),
+};
+
+static const struct samsung_pwm_variant s3c64xx_variant = {
+ .bits = 32,
+ .div_base = 0,
+ .has_tint_cstat = true,
+ .tclk_mask = (1 << 7) | (1 << 6) | (1 << 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 s5p_variant = {
+ .bits = 32,
+ .div_base = 0,
+ .has_tint_cstat = true,
+ .tclk_mask = (1 << 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 = &s5p_variant },
+ { .compatible = "samsung,exynos4210-pwm", .data = &s5p64x0_variant },
+ {},
+};
+#endif
+
+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) {
+ pr_warning("%s: invalid channel index in samsung,pwm-outputs property\n",
+ __func__);
+ continue;
+ }
+ chip->variant.output_mask |= 1 << val;
+ }
+
+ return 0;
+}
+
+static int pwm_samsung_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct samsung_pwm_chip *chip;
+ struct resource *res;
+ int ret;
+
+ chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+ if (chip == NULL) {
+ dev_err(dev, "failed to allocate driver data\n");
+ return -ENOMEM;
+ }
+
+ chip->chip.dev = &pdev->dev;
+ chip->chip.ops = &pwm_samsung_ops;
+ chip->chip.base = -1;
+ chip->chip.npwm = SAMSUNG_PWM_NUM;
+
+ if (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);
+ if (!res) {
+ dev_err(&pdev->dev, "failed to get mem resource\n");
+ return -ENOMEM;
+ }
+
+ chip->base = devm_request_and_ioremap(&pdev->dev, res);
+ if (!chip->base) {
+ dev_err(&pdev->dev, "failed to request and map registers\n");
+ return -ENOMEM;
+ }
+
+ 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);
+ }
+ clk_prepare_enable(chip->base_clk);
+
+ chip->tclk0 = devm_clk_get(&pdev->dev, "pwm-tclk0");
+ chip->tclk1 = devm_clk_get(&pdev->dev, "pwm-tclk1");
+
+ ret = pwmchip_add(&chip->chip);
+ if (ret < 0) {
+ dev_err(dev, "failed to register pwm\n");
+ goto err_clk_disable;
+ }
+
+ dev_info(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);
+
+ platform_set_drvdata(pdev, chip);
+
+ return 0;
+
+err_clk_disable:
+ clk_disable_unprepare(chip->base_clk);
+
+ return ret;
+}
+
+static int pwm_samsung_remove(struct platform_device *pdev)
+{
+ struct samsung_pwm_chip *chip = platform_get_drvdata(pdev);
+ int err;
+
+ err = pwmchip_remove(&chip->chip);
+ if (err < 0)
+ return err;
+
+ clk_disable_unprepare(chip->base_clk);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int pwm_samsung_suspend(struct device *dev)
+{
+ struct samsung_pwm_chip *chip = dev_get_drvdata(dev);
+ int i;
+
+ /* No one preserve these values during suspend so reset them
+ * Otherwise driver leaves PWM unconfigured if same values
+ * passed to pwm_config
+ */
+ for (i = 0; i < SAMSUNG_PWM_NUM; ++i) {
+ chip->channels[i].period_ns = 0;
+ chip->channels[i].duty_ns = 0;
+ }
+
+ return 0;
+}
+#endif
+
+static struct dev_pm_ops pwm_samsung_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(pwm_samsung_suspend, NULL)
+};
+
+static struct platform_driver pwm_samsung_driver = {
+ .driver = {
+ .name = "samsung-pwm",
+ .owner = THIS_MODULE,
+ .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@xxxxxxxxx>");
+MODULE_ALIAS("platform:samsung-pwm");
--
1.8.2.1
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