diff options
Diffstat (limited to 'drivers/pwm/pwm-sunplus.c')
| -rw-r--r-- | drivers/pwm/pwm-sunplus.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-sunplus.c b/drivers/pwm/pwm-sunplus.c new file mode 100644 index 000000000..d6ebe9f03 --- /dev/null +++ b/drivers/pwm/pwm-sunplus.c @@ -0,0 +1,234 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * PWM device driver for SUNPLUS SP7021 SoC + * + * Links: + * Reference Manual: + * https://sunplus-tibbo.atlassian.net/wiki/spaces/doc/overview + * + * Reference Manual(PWM module): + * https://sunplus.atlassian.net/wiki/spaces/doc/pages/461144198/12.+Pulse+Width+Modulation+PWM + * + * Limitations: + * - Only supports normal polarity. + * - It output low when PWM channel disabled. + * - When the parameters change, current running period will not be completed + * and run new settings immediately. + * - In .apply() PWM output need to write register FREQ and DUTY. When first write FREQ + * done and not yet write DUTY, it has short timing gap use new FREQ and old DUTY. + * + * Author: Hammer Hsieh <hammerh0314@gmail.com> + */ +#include <linux/bitfield.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> + +#define SP7021_PWM_MODE0 0x000 +#define SP7021_PWM_MODE0_PWMEN(ch) BIT(ch) +#define SP7021_PWM_MODE0_BYPASS(ch) BIT(8 + (ch)) +#define SP7021_PWM_MODE1 0x004 +#define SP7021_PWM_MODE1_CNT_EN(ch) BIT(ch) +#define SP7021_PWM_FREQ(ch) (0x008 + 4 * (ch)) +#define SP7021_PWM_FREQ_MAX GENMASK(15, 0) +#define SP7021_PWM_DUTY(ch) (0x018 + 4 * (ch)) +#define SP7021_PWM_DUTY_DD_SEL(ch) FIELD_PREP(GENMASK(9, 8), ch) +#define SP7021_PWM_DUTY_MAX GENMASK(7, 0) +#define SP7021_PWM_DUTY_MASK SP7021_PWM_DUTY_MAX +#define SP7021_PWM_FREQ_SCALER 256 +#define SP7021_PWM_NUM 4 + +struct sunplus_pwm { + struct pwm_chip chip; + void __iomem *base; + struct clk *clk; +}; + +static inline struct sunplus_pwm *to_sunplus_pwm(struct pwm_chip *chip) +{ + return container_of(chip, struct sunplus_pwm, chip); +} + +static int sunplus_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) +{ + struct sunplus_pwm *priv = to_sunplus_pwm(chip); + u32 dd_freq, duty, mode0, mode1; + u64 clk_rate; + + if (state->polarity != pwm->state.polarity) + return -EINVAL; + + if (!state->enabled) { + /* disable pwm channel output */ + mode0 = readl(priv->base + SP7021_PWM_MODE0); + mode0 &= ~SP7021_PWM_MODE0_PWMEN(pwm->hwpwm); + writel(mode0, priv->base + SP7021_PWM_MODE0); + /* disable pwm channel clk source */ + mode1 = readl(priv->base + SP7021_PWM_MODE1); + mode1 &= ~SP7021_PWM_MODE1_CNT_EN(pwm->hwpwm); + writel(mode1, priv->base + SP7021_PWM_MODE1); + return 0; + } + + clk_rate = clk_get_rate(priv->clk); + + /* + * The following calculations might overflow if clk is bigger + * than 256 GHz. In practise it's 202.5MHz, so this limitation + * is only theoretic. + */ + if (clk_rate > (u64)SP7021_PWM_FREQ_SCALER * NSEC_PER_SEC) + return -EINVAL; + + /* + * With clk_rate limited above we have dd_freq <= state->period, + * so this cannot overflow. + */ + dd_freq = mul_u64_u64_div_u64(clk_rate, state->period, (u64)SP7021_PWM_FREQ_SCALER + * NSEC_PER_SEC); + + if (dd_freq == 0) + return -EINVAL; + + if (dd_freq > SP7021_PWM_FREQ_MAX) + dd_freq = SP7021_PWM_FREQ_MAX; + + writel(dd_freq, priv->base + SP7021_PWM_FREQ(pwm->hwpwm)); + + /* cal and set pwm duty */ + mode0 = readl(priv->base + SP7021_PWM_MODE0); + mode0 |= SP7021_PWM_MODE0_PWMEN(pwm->hwpwm); + mode1 = readl(priv->base + SP7021_PWM_MODE1); + mode1 |= SP7021_PWM_MODE1_CNT_EN(pwm->hwpwm); + if (state->duty_cycle == state->period) { + /* PWM channel output = high */ + mode0 |= SP7021_PWM_MODE0_BYPASS(pwm->hwpwm); + duty = SP7021_PWM_DUTY_DD_SEL(pwm->hwpwm) | SP7021_PWM_DUTY_MAX; + } else { + mode0 &= ~SP7021_PWM_MODE0_BYPASS(pwm->hwpwm); + /* + * duty_ns <= period_ns 27 bits, clk_rate 28 bits, won't overflow. + */ + duty = mul_u64_u64_div_u64(state->duty_cycle, clk_rate, + (u64)dd_freq * NSEC_PER_SEC); + duty = SP7021_PWM_DUTY_DD_SEL(pwm->hwpwm) | duty; + } + writel(duty, priv->base + SP7021_PWM_DUTY(pwm->hwpwm)); + writel(mode1, priv->base + SP7021_PWM_MODE1); + writel(mode0, priv->base + SP7021_PWM_MODE0); + + return 0; +} + +static int sunplus_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct sunplus_pwm *priv = to_sunplus_pwm(chip); + u32 mode0, dd_freq, duty; + u64 clk_rate; + + mode0 = readl(priv->base + SP7021_PWM_MODE0); + + if (mode0 & BIT(pwm->hwpwm)) { + clk_rate = clk_get_rate(priv->clk); + dd_freq = readl(priv->base + SP7021_PWM_FREQ(pwm->hwpwm)); + duty = readl(priv->base + SP7021_PWM_DUTY(pwm->hwpwm)); + duty = FIELD_GET(SP7021_PWM_DUTY_MASK, duty); + /* + * dd_freq 16 bits, SP7021_PWM_FREQ_SCALER 8 bits + * NSEC_PER_SEC 30 bits, won't overflow. + */ + state->period = DIV64_U64_ROUND_UP((u64)dd_freq * (u64)SP7021_PWM_FREQ_SCALER + * NSEC_PER_SEC, clk_rate); + /* + * dd_freq 16 bits, duty 8 bits, NSEC_PER_SEC 30 bits, won't overflow. + */ + state->duty_cycle = DIV64_U64_ROUND_UP((u64)dd_freq * (u64)duty * NSEC_PER_SEC, + clk_rate); + state->enabled = true; + } else { + state->enabled = false; + } + + state->polarity = PWM_POLARITY_NORMAL; + + return 0; +} + +static const struct pwm_ops sunplus_pwm_ops = { + .apply = sunplus_pwm_apply, + .get_state = sunplus_pwm_get_state, + .owner = THIS_MODULE, +}; + +static void sunplus_pwm_clk_release(void *data) +{ + struct clk *clk = data; + + clk_disable_unprepare(clk); +} + +static int sunplus_pwm_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct sunplus_pwm *priv; + int ret; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(priv->base)) + return PTR_ERR(priv->base); + + priv->clk = devm_clk_get(dev, NULL); + if (IS_ERR(priv->clk)) + return dev_err_probe(dev, PTR_ERR(priv->clk), + "get pwm clock failed\n"); + + ret = clk_prepare_enable(priv->clk); + if (ret < 0) { + dev_err(dev, "failed to enable clock: %d\n", ret); + return ret; + } + + ret = devm_add_action_or_reset(dev, sunplus_pwm_clk_release, priv->clk); + if (ret < 0) { + dev_err(dev, "failed to release clock: %d\n", ret); + return ret; + } + + priv->chip.dev = dev; + priv->chip.ops = &sunplus_pwm_ops; + priv->chip.npwm = SP7021_PWM_NUM; + + ret = devm_pwmchip_add(dev, &priv->chip); + if (ret < 0) + return dev_err_probe(dev, ret, "Cannot register sunplus PWM\n"); + + return 0; +} + +static const struct of_device_id sunplus_pwm_of_match[] = { + { .compatible = "sunplus,sp7021-pwm", }, + {} +}; +MODULE_DEVICE_TABLE(of, sunplus_pwm_of_match); + +static struct platform_driver sunplus_pwm_driver = { + .probe = sunplus_pwm_probe, + .driver = { + .name = "sunplus-pwm", + .of_match_table = sunplus_pwm_of_match, + }, +}; +module_platform_driver(sunplus_pwm_driver); + +MODULE_DESCRIPTION("Sunplus SoC PWM Driver"); +MODULE_AUTHOR("Hammer Hsieh <hammerh0314@gmail.com>"); +MODULE_LICENSE("GPL"); |