diff options
Diffstat (limited to 'kernel/drivers/pwm/pwm-sun4i.c')
| -rw-r--r-- | kernel/drivers/pwm/pwm-sun4i.c | 366 |
1 files changed, 366 insertions, 0 deletions
diff --git a/kernel/drivers/pwm/pwm-sun4i.c b/kernel/drivers/pwm/pwm-sun4i.c new file mode 100644 index 000000000..cd9dde563 --- /dev/null +++ b/kernel/drivers/pwm/pwm-sun4i.c @@ -0,0 +1,366 @@ +/* + * Driver for Allwinner sun4i Pulse Width Modulation Controller + * + * Copyright (C) 2014 Alexandre Belloni <alexandre.belloni@free-electrons.com> + * + * Licensed under GPLv2. + */ + +#include <linux/bitops.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/time.h> + +#define PWM_CTRL_REG 0x0 + +#define PWM_CH_PRD_BASE 0x4 +#define PWM_CH_PRD_OFFSET 0x4 +#define PWM_CH_PRD(ch) (PWM_CH_PRD_BASE + PWM_CH_PRD_OFFSET * (ch)) + +#define PWMCH_OFFSET 15 +#define PWM_PRESCAL_MASK GENMASK(3, 0) +#define PWM_PRESCAL_OFF 0 +#define PWM_EN BIT(4) +#define PWM_ACT_STATE BIT(5) +#define PWM_CLK_GATING BIT(6) +#define PWM_MODE BIT(7) +#define PWM_PULSE BIT(8) +#define PWM_BYPASS BIT(9) + +#define PWM_RDY_BASE 28 +#define PWM_RDY_OFFSET 1 +#define PWM_RDY(ch) BIT(PWM_RDY_BASE + PWM_RDY_OFFSET * (ch)) + +#define PWM_PRD(prd) (((prd) - 1) << 16) +#define PWM_PRD_MASK GENMASK(15, 0) + +#define PWM_DTY_MASK GENMASK(15, 0) + +#define BIT_CH(bit, chan) ((bit) << ((chan) * PWMCH_OFFSET)) + +static const u32 prescaler_table[] = { + 120, + 180, + 240, + 360, + 480, + 0, + 0, + 0, + 12000, + 24000, + 36000, + 48000, + 72000, + 0, + 0, + 0, /* Actually 1 but tested separately */ +}; + +struct sun4i_pwm_data { + bool has_prescaler_bypass; + bool has_rdy; +}; + +struct sun4i_pwm_chip { + struct pwm_chip chip; + struct clk *clk; + void __iomem *base; + spinlock_t ctrl_lock; + const struct sun4i_pwm_data *data; +}; + +static inline struct sun4i_pwm_chip *to_sun4i_pwm_chip(struct pwm_chip *chip) +{ + return container_of(chip, struct sun4i_pwm_chip, chip); +} + +static inline u32 sun4i_pwm_readl(struct sun4i_pwm_chip *chip, + unsigned long offset) +{ + return readl(chip->base + offset); +} + +static inline void sun4i_pwm_writel(struct sun4i_pwm_chip *chip, + u32 val, unsigned long offset) +{ + writel(val, chip->base + offset); +} + +static int sun4i_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip); + u32 prd, dty, val, clk_gate; + u64 clk_rate, div = 0; + unsigned int prescaler = 0; + int err; + + clk_rate = clk_get_rate(sun4i_pwm->clk); + + if (sun4i_pwm->data->has_prescaler_bypass) { + /* First, test without any prescaler when available */ + prescaler = PWM_PRESCAL_MASK; + /* + * When not using any prescaler, the clock period in nanoseconds + * is not an integer so round it half up instead of + * truncating to get less surprising values. + */ + div = clk_rate * period_ns + NSEC_PER_SEC/2; + do_div(div, NSEC_PER_SEC); + if (div - 1 > PWM_PRD_MASK) + prescaler = 0; + } + + if (prescaler == 0) { + /* Go up from the first divider */ + for (prescaler = 0; prescaler < PWM_PRESCAL_MASK; prescaler++) { + if (!prescaler_table[prescaler]) + continue; + div = clk_rate; + do_div(div, prescaler_table[prescaler]); + div = div * period_ns; + do_div(div, NSEC_PER_SEC); + if (div - 1 <= PWM_PRD_MASK) + break; + } + + if (div - 1 > PWM_PRD_MASK) { + dev_err(chip->dev, "period exceeds the maximum value\n"); + return -EINVAL; + } + } + + prd = div; + div *= duty_ns; + do_div(div, period_ns); + dty = div; + + err = clk_prepare_enable(sun4i_pwm->clk); + if (err) { + dev_err(chip->dev, "failed to enable PWM clock\n"); + return err; + } + + spin_lock(&sun4i_pwm->ctrl_lock); + val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); + + if (sun4i_pwm->data->has_rdy && (val & PWM_RDY(pwm->hwpwm))) { + spin_unlock(&sun4i_pwm->ctrl_lock); + clk_disable_unprepare(sun4i_pwm->clk); + return -EBUSY; + } + + clk_gate = val & BIT_CH(PWM_CLK_GATING, pwm->hwpwm); + if (clk_gate) { + val &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm); + sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG); + } + + val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); + val &= ~BIT_CH(PWM_PRESCAL_MASK, pwm->hwpwm); + val |= BIT_CH(prescaler, pwm->hwpwm); + sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG); + + val = (dty & PWM_DTY_MASK) | PWM_PRD(prd); + sun4i_pwm_writel(sun4i_pwm, val, PWM_CH_PRD(pwm->hwpwm)); + + if (clk_gate) { + val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); + val |= clk_gate; + sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG); + } + + spin_unlock(&sun4i_pwm->ctrl_lock); + clk_disable_unprepare(sun4i_pwm->clk); + + return 0; +} + +static int sun4i_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, + enum pwm_polarity polarity) +{ + struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip); + u32 val; + int ret; + + ret = clk_prepare_enable(sun4i_pwm->clk); + if (ret) { + dev_err(chip->dev, "failed to enable PWM clock\n"); + return ret; + } + + spin_lock(&sun4i_pwm->ctrl_lock); + val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); + + if (polarity != PWM_POLARITY_NORMAL) + val &= ~BIT_CH(PWM_ACT_STATE, pwm->hwpwm); + else + val |= BIT_CH(PWM_ACT_STATE, pwm->hwpwm); + + sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG); + + spin_unlock(&sun4i_pwm->ctrl_lock); + clk_disable_unprepare(sun4i_pwm->clk); + + return 0; +} + +static int sun4i_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip); + u32 val; + int ret; + + ret = clk_prepare_enable(sun4i_pwm->clk); + if (ret) { + dev_err(chip->dev, "failed to enable PWM clock\n"); + return ret; + } + + spin_lock(&sun4i_pwm->ctrl_lock); + val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); + val |= BIT_CH(PWM_EN, pwm->hwpwm); + val |= BIT_CH(PWM_CLK_GATING, pwm->hwpwm); + sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG); + spin_unlock(&sun4i_pwm->ctrl_lock); + + return 0; +} + +static void sun4i_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip); + u32 val; + + spin_lock(&sun4i_pwm->ctrl_lock); + val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); + val &= ~BIT_CH(PWM_EN, pwm->hwpwm); + val &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm); + sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG); + spin_unlock(&sun4i_pwm->ctrl_lock); + + clk_disable_unprepare(sun4i_pwm->clk); +} + +static const struct pwm_ops sun4i_pwm_ops = { + .config = sun4i_pwm_config, + .set_polarity = sun4i_pwm_set_polarity, + .enable = sun4i_pwm_enable, + .disable = sun4i_pwm_disable, + .owner = THIS_MODULE, +}; + +static const struct sun4i_pwm_data sun4i_pwm_data_a10 = { + .has_prescaler_bypass = false, + .has_rdy = false, +}; + +static const struct sun4i_pwm_data sun4i_pwm_data_a20 = { + .has_prescaler_bypass = true, + .has_rdy = true, +}; + +static const struct of_device_id sun4i_pwm_dt_ids[] = { + { + .compatible = "allwinner,sun4i-a10-pwm", + .data = &sun4i_pwm_data_a10, + }, { + .compatible = "allwinner,sun7i-a20-pwm", + .data = &sun4i_pwm_data_a20, + }, { + /* sentinel */ + }, +}; +MODULE_DEVICE_TABLE(of, sun4i_pwm_dt_ids); + +static int sun4i_pwm_probe(struct platform_device *pdev) +{ + struct sun4i_pwm_chip *pwm; + struct resource *res; + u32 val; + int i, ret; + const struct of_device_id *match; + + match = of_match_device(sun4i_pwm_dt_ids, &pdev->dev); + + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); + if (!pwm) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + pwm->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(pwm->base)) + return PTR_ERR(pwm->base); + + pwm->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(pwm->clk)) + return PTR_ERR(pwm->clk); + + pwm->chip.dev = &pdev->dev; + pwm->chip.ops = &sun4i_pwm_ops; + pwm->chip.base = -1; + pwm->chip.npwm = 2; + pwm->chip.can_sleep = true; + pwm->chip.of_xlate = of_pwm_xlate_with_flags; + pwm->chip.of_pwm_n_cells = 3; + pwm->data = match->data; + + spin_lock_init(&pwm->ctrl_lock); + + ret = pwmchip_add(&pwm->chip); + if (ret < 0) { + dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret); + return ret; + } + + platform_set_drvdata(pdev, pwm); + + ret = clk_prepare_enable(pwm->clk); + if (ret) { + dev_err(&pdev->dev, "failed to enable PWM clock\n"); + goto clk_error; + } + + val = sun4i_pwm_readl(pwm, PWM_CTRL_REG); + for (i = 0; i < pwm->chip.npwm; i++) + if (!(val & BIT_CH(PWM_ACT_STATE, i))) + pwm->chip.pwms[i].polarity = PWM_POLARITY_INVERSED; + clk_disable_unprepare(pwm->clk); + + return 0; + +clk_error: + pwmchip_remove(&pwm->chip); + return ret; +} + +static int sun4i_pwm_remove(struct platform_device *pdev) +{ + struct sun4i_pwm_chip *pwm = platform_get_drvdata(pdev); + + return pwmchip_remove(&pwm->chip); +} + +static struct platform_driver sun4i_pwm_driver = { + .driver = { + .name = "sun4i-pwm", + .of_match_table = sun4i_pwm_dt_ids, + }, + .probe = sun4i_pwm_probe, + .remove = sun4i_pwm_remove, +}; +module_platform_driver(sun4i_pwm_driver); + +MODULE_ALIAS("platform:sun4i-pwm"); +MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>"); +MODULE_DESCRIPTION("Allwinner sun4i PWM driver"); +MODULE_LICENSE("GPL v2"); |