diff options
Diffstat (limited to 'kernel/drivers/pwm/pwm-atmel.c')
| -rw-r--r-- | kernel/drivers/pwm/pwm-atmel.c | 399 |
1 files changed, 399 insertions, 0 deletions
diff --git a/kernel/drivers/pwm/pwm-atmel.c b/kernel/drivers/pwm/pwm-atmel.c new file mode 100644 index 000000000..d3c22de9e --- /dev/null +++ b/kernel/drivers/pwm/pwm-atmel.c @@ -0,0 +1,399 @@ +/* + * Driver for Atmel Pulse Width Modulation Controller + * + * Copyright (C) 2013 Atmel Corporation + * Bo Shen <voice.shen@atmel.com> + * + * Licensed under GPLv2. + */ + +#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> + +/* The following is global registers for PWM controller */ +#define PWM_ENA 0x04 +#define PWM_DIS 0x08 +#define PWM_SR 0x0C +/* Bit field in SR */ +#define PWM_SR_ALL_CH_ON 0x0F + +/* The following register is PWM channel related registers */ +#define PWM_CH_REG_OFFSET 0x200 +#define PWM_CH_REG_SIZE 0x20 + +#define PWM_CMR 0x0 +/* Bit field in CMR */ +#define PWM_CMR_CPOL (1 << 9) +#define PWM_CMR_UPD_CDTY (1 << 10) +#define PWM_CMR_CPRE_MSK 0xF + +/* The following registers for PWM v1 */ +#define PWMV1_CDTY 0x04 +#define PWMV1_CPRD 0x08 +#define PWMV1_CUPD 0x10 + +/* The following registers for PWM v2 */ +#define PWMV2_CDTY 0x04 +#define PWMV2_CDTYUPD 0x08 +#define PWMV2_CPRD 0x0C +#define PWMV2_CPRDUPD 0x10 + +/* + * Max value for duty and period + * + * Although the duty and period register is 32 bit, + * however only the LSB 16 bits are significant. + */ +#define PWM_MAX_DTY 0xFFFF +#define PWM_MAX_PRD 0xFFFF +#define PRD_MAX_PRES 10 + +struct atmel_pwm_chip { + struct pwm_chip chip; + struct clk *clk; + void __iomem *base; + + void (*config)(struct pwm_chip *chip, struct pwm_device *pwm, + unsigned long dty, unsigned long prd); +}; + +static inline struct atmel_pwm_chip *to_atmel_pwm_chip(struct pwm_chip *chip) +{ + return container_of(chip, struct atmel_pwm_chip, chip); +} + +static inline u32 atmel_pwm_readl(struct atmel_pwm_chip *chip, + unsigned long offset) +{ + return readl_relaxed(chip->base + offset); +} + +static inline void atmel_pwm_writel(struct atmel_pwm_chip *chip, + unsigned long offset, unsigned long val) +{ + writel_relaxed(val, chip->base + offset); +} + +static inline u32 atmel_pwm_ch_readl(struct atmel_pwm_chip *chip, + unsigned int ch, unsigned long offset) +{ + unsigned long base = PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE; + + return readl_relaxed(chip->base + base + offset); +} + +static inline void atmel_pwm_ch_writel(struct atmel_pwm_chip *chip, + unsigned int ch, unsigned long offset, + unsigned long val) +{ + unsigned long base = PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE; + + writel_relaxed(val, chip->base + base + offset); +} + +static int atmel_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); + unsigned long prd, dty; + unsigned long long div; + unsigned int pres = 0; + u32 val; + int ret; + + if (test_bit(PWMF_ENABLED, &pwm->flags) && (period_ns != pwm->period)) { + dev_err(chip->dev, "cannot change PWM period while enabled\n"); + return -EBUSY; + } + + /* Calculate the period cycles and prescale value */ + div = (unsigned long long)clk_get_rate(atmel_pwm->clk) * period_ns; + do_div(div, NSEC_PER_SEC); + + while (div > PWM_MAX_PRD) { + div >>= 1; + pres++; + } + + if (pres > PRD_MAX_PRES) { + dev_err(chip->dev, "pres exceeds the maximum value\n"); + return -EINVAL; + } + + /* Calculate the duty cycles */ + prd = div; + div *= duty_ns; + do_div(div, period_ns); + dty = prd - div; + + ret = clk_enable(atmel_pwm->clk); + if (ret) { + dev_err(chip->dev, "failed to enable PWM clock\n"); + return ret; + } + + /* It is necessary to preserve CPOL, inside CMR */ + val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR); + val = (val & ~PWM_CMR_CPRE_MSK) | (pres & PWM_CMR_CPRE_MSK); + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); + atmel_pwm->config(chip, pwm, dty, prd); + + clk_disable(atmel_pwm->clk); + return ret; +} + +static void atmel_pwm_config_v1(struct pwm_chip *chip, struct pwm_device *pwm, + unsigned long dty, unsigned long prd) +{ + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); + unsigned int val; + + if (test_bit(PWMF_ENABLED, &pwm->flags)) { + /* + * If the PWM channel is enabled, using the update register, + * it needs to set bit 10 of CMR to 0 + */ + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CUPD, dty); + + val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR); + val &= ~PWM_CMR_UPD_CDTY; + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); + } else { + /* + * If the PWM channel is disabled, write value to duty and + * period registers directly. + */ + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CDTY, dty); + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CPRD, prd); + } +} + +static void atmel_pwm_config_v2(struct pwm_chip *chip, struct pwm_device *pwm, + unsigned long dty, unsigned long prd) +{ + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); + + if (test_bit(PWMF_ENABLED, &pwm->flags)) { + /* + * If the PWM channel is enabled, using the duty update register + * to update the value. + */ + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV2_CDTYUPD, dty); + } else { + /* + * If the PWM channel is disabled, write value to duty and + * period registers directly. + */ + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV2_CDTY, dty); + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV2_CPRD, prd); + } +} + +static int atmel_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, + enum pwm_polarity polarity) +{ + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); + u32 val; + int ret; + + val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR); + + if (polarity == PWM_POLARITY_NORMAL) + val &= ~PWM_CMR_CPOL; + else + val |= PWM_CMR_CPOL; + + ret = clk_enable(atmel_pwm->clk); + if (ret) { + dev_err(chip->dev, "failed to enable PWM clock\n"); + return ret; + } + + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); + + clk_disable(atmel_pwm->clk); + + return 0; +} + +static int atmel_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); + int ret; + + ret = clk_enable(atmel_pwm->clk); + if (ret) { + dev_err(chip->dev, "failed to enable PWM clock\n"); + return ret; + } + + atmel_pwm_writel(atmel_pwm, PWM_ENA, 1 << pwm->hwpwm); + + return 0; +} + +static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); + + atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm); + + clk_disable(atmel_pwm->clk); +} + +static const struct pwm_ops atmel_pwm_ops = { + .config = atmel_pwm_config, + .set_polarity = atmel_pwm_set_polarity, + .enable = atmel_pwm_enable, + .disable = atmel_pwm_disable, + .owner = THIS_MODULE, +}; + +struct atmel_pwm_data { + void (*config)(struct pwm_chip *chip, struct pwm_device *pwm, + unsigned long dty, unsigned long prd); +}; + +static const struct atmel_pwm_data atmel_pwm_data_v1 = { + .config = atmel_pwm_config_v1, +}; + +static const struct atmel_pwm_data atmel_pwm_data_v2 = { + .config = atmel_pwm_config_v2, +}; + +static const struct platform_device_id atmel_pwm_devtypes[] = { + { + .name = "at91sam9rl-pwm", + .driver_data = (kernel_ulong_t)&atmel_pwm_data_v1, + }, { + .name = "sama5d3-pwm", + .driver_data = (kernel_ulong_t)&atmel_pwm_data_v2, + }, { + /* sentinel */ + }, +}; +MODULE_DEVICE_TABLE(platform, atmel_pwm_devtypes); + +static const struct of_device_id atmel_pwm_dt_ids[] = { + { + .compatible = "atmel,at91sam9rl-pwm", + .data = &atmel_pwm_data_v1, + }, { + .compatible = "atmel,sama5d3-pwm", + .data = &atmel_pwm_data_v2, + }, { + /* sentinel */ + }, +}; +MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids); + +static inline const struct atmel_pwm_data * +atmel_pwm_get_driver_data(struct platform_device *pdev) +{ + if (pdev->dev.of_node) { + const struct of_device_id *match; + + match = of_match_device(atmel_pwm_dt_ids, &pdev->dev); + if (!match) + return NULL; + + return match->data; + } else { + const struct platform_device_id *id; + + id = platform_get_device_id(pdev); + + return (struct atmel_pwm_data *)id->driver_data; + } +} + +static int atmel_pwm_probe(struct platform_device *pdev) +{ + const struct atmel_pwm_data *data; + struct atmel_pwm_chip *atmel_pwm; + struct resource *res; + int ret; + + data = atmel_pwm_get_driver_data(pdev); + if (!data) + return -ENODEV; + + atmel_pwm = devm_kzalloc(&pdev->dev, sizeof(*atmel_pwm), GFP_KERNEL); + if (!atmel_pwm) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + atmel_pwm->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(atmel_pwm->base)) + return PTR_ERR(atmel_pwm->base); + + atmel_pwm->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(atmel_pwm->clk)) + return PTR_ERR(atmel_pwm->clk); + + ret = clk_prepare(atmel_pwm->clk); + if (ret) { + dev_err(&pdev->dev, "failed to prepare PWM clock\n"); + return ret; + } + + atmel_pwm->chip.dev = &pdev->dev; + atmel_pwm->chip.ops = &atmel_pwm_ops; + + if (pdev->dev.of_node) { + atmel_pwm->chip.of_xlate = of_pwm_xlate_with_flags; + atmel_pwm->chip.of_pwm_n_cells = 3; + } + + atmel_pwm->chip.base = -1; + atmel_pwm->chip.npwm = 4; + atmel_pwm->chip.can_sleep = true; + atmel_pwm->config = data->config; + + ret = pwmchip_add(&atmel_pwm->chip); + if (ret < 0) { + dev_err(&pdev->dev, "failed to add PWM chip %d\n", ret); + goto unprepare_clk; + } + + platform_set_drvdata(pdev, atmel_pwm); + + return ret; + +unprepare_clk: + clk_unprepare(atmel_pwm->clk); + return ret; +} + +static int atmel_pwm_remove(struct platform_device *pdev) +{ + struct atmel_pwm_chip *atmel_pwm = platform_get_drvdata(pdev); + + clk_unprepare(atmel_pwm->clk); + + return pwmchip_remove(&atmel_pwm->chip); +} + +static struct platform_driver atmel_pwm_driver = { + .driver = { + .name = "atmel-pwm", + .of_match_table = of_match_ptr(atmel_pwm_dt_ids), + }, + .id_table = atmel_pwm_devtypes, + .probe = atmel_pwm_probe, + .remove = atmel_pwm_remove, +}; +module_platform_driver(atmel_pwm_driver); + +MODULE_ALIAS("platform:atmel-pwm"); +MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>"); +MODULE_DESCRIPTION("Atmel PWM driver"); +MODULE_LICENSE("GPL v2"); |