/* * R-Car PWM Timer driver * * Copyright (C) 2015 Renesas Electronics Corporation * * This is free software; you can redistribute it and/or modify * it under the terms of version 2 of the GNU General Public License as * published by the Free Software Foundation. */ #include <linux/clk.h> #include <linux/err.h> #include <linux/io.h> #include <linux/module.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/pm_runtime.h> #include <linux/pwm.h> #include <linux/slab.h> #define RCAR_PWM_MAX_DIVISION 24 #define RCAR_PWM_MAX_CYCLE 1023 #define RCAR_PWMCR 0x00 #define RCAR_PWMCR_CC0_MASK 0x000f0000 #define RCAR_PWMCR_CC0_SHIFT 16 #define RCAR_PWMCR_CCMD BIT(15) #define RCAR_PWMCR_SYNC BIT(11) #define RCAR_PWMCR_SS0 BIT(4) #define RCAR_PWMCR_EN0 BIT(0) #define RCAR_PWMCNT 0x04 #define RCAR_PWMCNT_CYC0_MASK 0x03ff0000 #define RCAR_PWMCNT_CYC0_SHIFT 16 #define RCAR_PWMCNT_PH0_MASK 0x000003ff #define RCAR_PWMCNT_PH0_SHIFT 0 struct rcar_pwm_chip { struct pwm_chip chip; void __iomem *base; struct clk *clk; }; static inline struct rcar_pwm_chip *to_rcar_pwm_chip(struct pwm_chip *chip) { return container_of(chip, struct rcar_pwm_chip, chip); } static void rcar_pwm_write(struct rcar_pwm_chip *rp, u32 data, unsigned int offset) { writel(data, rp->base + offset); } static u32 rcar_pwm_read(struct rcar_pwm_chip *rp, unsigned int offset) { return readl(rp->base + offset); } static void rcar_pwm_update(struct rcar_pwm_chip *rp, u32 mask, u32 data, unsigned int offset) { u32 value; value = rcar_pwm_read(rp, offset); value &= ~mask; value |= data & mask; rcar_pwm_write(rp, value, offset); } static int rcar_pwm_get_clock_division(struct rcar_pwm_chip *rp, int period_ns) { unsigned long clk_rate = clk_get_rate(rp->clk); unsigned long long max; /* max cycle / nanoseconds */ unsigned int div; if (clk_rate == 0) return -EINVAL; for (div = 0; div <= RCAR_PWM_MAX_DIVISION; div++) { max = (unsigned long long)NSEC_PER_SEC * RCAR_PWM_MAX_CYCLE * (1 << div); do_div(max, clk_rate); if (period_ns <= max) break; } return (div <= RCAR_PWM_MAX_DIVISION) ? div : -ERANGE; } static void rcar_pwm_set_clock_control(struct rcar_pwm_chip *rp, unsigned int div) { u32 value; value = rcar_pwm_read(rp, RCAR_PWMCR); value &= ~(RCAR_PWMCR_CCMD | RCAR_PWMCR_CC0_MASK); if (div & 1) value |= RCAR_PWMCR_CCMD; div >>= 1; value |= div << RCAR_PWMCR_CC0_SHIFT; rcar_pwm_write(rp, value, RCAR_PWMCR); } static int rcar_pwm_set_counter(struct rcar_pwm_chip *rp, int div, int duty_ns, int period_ns) { unsigned long long one_cycle, tmp; /* 0.01 nanoseconds */ unsigned long clk_rate = clk_get_rate(rp->clk); u32 cyc, ph; one_cycle = (unsigned long long)NSEC_PER_SEC * 100ULL * (1 << div); do_div(one_cycle, clk_rate); tmp = period_ns * 100ULL; do_div(tmp, one_cycle); cyc = (tmp << RCAR_PWMCNT_CYC0_SHIFT) & RCAR_PWMCNT_CYC0_MASK; tmp = duty_ns * 100ULL; do_div(tmp, one_cycle); ph = tmp & RCAR_PWMCNT_PH0_MASK; /* Avoid prohibited setting */ if (cyc == 0 || ph == 0) return -EINVAL; rcar_pwm_write(rp, cyc | ph, RCAR_PWMCNT); return 0; } static int rcar_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) { struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip); return clk_prepare_enable(rp->clk); } static void rcar_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) { struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip); clk_disable_unprepare(rp->clk); } static int rcar_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns) { struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip); int div, ret; div = rcar_pwm_get_clock_division(rp, period_ns); if (div < 0) return div; /* Let the core driver set pwm->period if disabled and duty_ns == 0 */ if (!pwm_is_enabled(pwm) && !duty_ns) return 0; rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR); ret = rcar_pwm_set_counter(rp, div, duty_ns, period_ns); if (!ret) rcar_pwm_set_clock_control(rp, div); /* The SYNC should be set to 0 even if rcar_pwm_set_counter failed */ rcar_pwm_update(rp, RCAR_PWMCR_SYNC, 0, RCAR_PWMCR); return ret; } static int rcar_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) { struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip); u32 value; /* Don't enable the PWM device if CYC0 or PH0 is 0 */ value = rcar_pwm_read(rp, RCAR_PWMCNT); if ((value & RCAR_PWMCNT_CYC0_MASK) == 0 || (value & RCAR_PWMCNT_PH0_MASK) == 0) return -EINVAL; rcar_pwm_update(rp, RCAR_PWMCR_EN0, RCAR_PWMCR_EN0, RCAR_PWMCR); return 0; } static void rcar_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) { struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip); rcar_pwm_update(rp, RCAR_PWMCR_EN0, 0, RCAR_PWMCR); } static const struct pwm_ops rcar_pwm_ops = { .request = rcar_pwm_request, .free = rcar_pwm_free, .config = rcar_pwm_config, .enable = rcar_pwm_enable, .disable = rcar_pwm_disable, .owner = THIS_MODULE, }; static int rcar_pwm_probe(struct platform_device *pdev) { struct rcar_pwm_chip *rcar_pwm; struct resource *res; int ret; rcar_pwm = devm_kzalloc(&pdev->dev, sizeof(*rcar_pwm), GFP_KERNEL); if (rcar_pwm == NULL) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); rcar_pwm->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(rcar_pwm->base)) return PTR_ERR(rcar_pwm->base); rcar_pwm->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(rcar_pwm->clk)) { dev_err(&pdev->dev, "cannot get clock\n"); return PTR_ERR(rcar_pwm->clk); } platform_set_drvdata(pdev, rcar_pwm); rcar_pwm->chip.dev = &pdev->dev; rcar_pwm->chip.ops = &rcar_pwm_ops; rcar_pwm->chip.base = -1; rcar_pwm->chip.npwm = 1; ret = pwmchip_add(&rcar_pwm->chip); if (ret < 0) { dev_err(&pdev->dev, "failed to register PWM chip: %d\n", ret); return ret; } pm_runtime_enable(&pdev->dev); return 0; } static int rcar_pwm_remove(struct platform_device *pdev) { struct rcar_pwm_chip *rcar_pwm = platform_get_drvdata(pdev); pm_runtime_disable(&pdev->dev); return pwmchip_remove(&rcar_pwm->chip); } static const struct of_device_id rcar_pwm_of_table[] = { { .compatible = "renesas,pwm-rcar", }, { }, }; MODULE_DEVICE_TABLE(of, rcar_pwm_of_table); static struct platform_driver rcar_pwm_driver = { .probe = rcar_pwm_probe, .remove = rcar_pwm_remove, .driver = { .name = "pwm-rcar", .of_match_table = of_match_ptr(rcar_pwm_of_table), } }; module_platform_driver(rcar_pwm_driver); MODULE_AUTHOR("Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>"); MODULE_DESCRIPTION("Renesas PWM Timer Driver"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:pwm-rcar");