/* * ECAP PWM driver * * Copyright (C) 2012 Texas Instruments, Inc. - http://www.ti.com/ * * 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, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include <linux/module.h> #include <linux/platform_device.h> #include <linux/io.h> #include <linux/err.h> #include <linux/clk.h> #include <linux/pm_runtime.h> #include <linux/pwm.h> /* ECAP registers and bits definitions */ #define CAP1 0x08 #define CAP2 0x0C #define CAP3 0x10 #define CAP4 0x14 #define ECCTL2 0x2A #define ECCTL2_APWM_POL_LOW BIT(10) #define ECCTL2_APWM_MODE BIT(9) #define ECCTL2_SYNC_SEL_DISA (BIT(7) | BIT(6)) #define ECCTL2_TSCTR_FREERUN BIT(4) struct ecap_pwm_chip { struct pwm_chip chip; unsigned int clk_rate; void __iomem *mmio_base; }; static inline struct ecap_pwm_chip *to_ecap_pwm_chip(struct pwm_chip *chip) { return container_of(chip, struct ecap_pwm_chip, chip); } /* * period_ns = 10^9 * period_cycles / PWM_CLK_RATE * duty_ns = 10^9 * duty_cycles / PWM_CLK_RATE */ static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns) { struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip); unsigned long long c; unsigned long period_cycles, duty_cycles; unsigned int reg_val; if (period_ns > NSEC_PER_SEC) return -ERANGE; c = pc->clk_rate; c = c * period_ns; do_div(c, NSEC_PER_SEC); period_cycles = (unsigned long)c; if (period_cycles < 1) { period_cycles = 1; duty_cycles = 1; } else { c = pc->clk_rate; c = c * duty_ns; do_div(c, NSEC_PER_SEC); duty_cycles = (unsigned long)c; } pm_runtime_get_sync(pc->chip.dev); reg_val = readw(pc->mmio_base + ECCTL2); /* Configure APWM mode & disable sync option */ reg_val |= ECCTL2_APWM_MODE | ECCTL2_SYNC_SEL_DISA; writew(reg_val, pc->mmio_base + ECCTL2); if (!test_bit(PWMF_ENABLED, &pwm->flags)) { /* Update active registers if not running */ writel(duty_cycles, pc->mmio_base + CAP2); writel(period_cycles, pc->mmio_base + CAP1); } else { /* * Update shadow registers to configure period and * compare values. This helps current PWM period to * complete on reconfiguring */ writel(duty_cycles, pc->mmio_base + CAP4); writel(period_cycles, pc->mmio_base + CAP3); } if (!test_bit(PWMF_ENABLED, &pwm->flags)) { reg_val = readw(pc->mmio_base + ECCTL2); /* Disable APWM mode to put APWM output Low */ reg_val &= ~ECCTL2_APWM_MODE; writew(reg_val, pc->mmio_base + ECCTL2); } pm_runtime_put_sync(pc->chip.dev); return 0; } static int ecap_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, enum pwm_polarity polarity) { struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip); unsigned short reg_val; pm_runtime_get_sync(pc->chip.dev); reg_val = readw(pc->mmio_base + ECCTL2); if (polarity == PWM_POLARITY_INVERSED) /* Duty cycle defines LOW period of PWM */ reg_val |= ECCTL2_APWM_POL_LOW; else /* Duty cycle defines HIGH period of PWM */ reg_val &= ~ECCTL2_APWM_POL_LOW; writew(reg_val, pc->mmio_base + ECCTL2); pm_runtime_put_sync(pc->chip.dev); return 0; } static int ecap_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) { struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip); unsigned int reg_val; /* Leave clock enabled on enabling PWM */ pm_runtime_get_sync(pc->chip.dev); /* * Enable 'Free run Time stamp counter mode' to start counter * and 'APWM mode' to enable APWM output */ reg_val = readw(pc->mmio_base + ECCTL2); reg_val |= ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE; writew(reg_val, pc->mmio_base + ECCTL2); return 0; } static void ecap_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) { struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip); unsigned int reg_val; /* * Disable 'Free run Time stamp counter mode' to stop counter * and 'APWM mode' to put APWM output to low */ reg_val = readw(pc->mmio_base + ECCTL2); reg_val &= ~(ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE); writew(reg_val, pc->mmio_base + ECCTL2); /* Disable clock on PWM disable */ pm_runtime_put_sync(pc->chip.dev); } static void ecap_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) { if (test_bit(PWMF_ENABLED, &pwm->flags)) { dev_warn(chip->dev, "Removing PWM device without disabling\n"); pm_runtime_put_sync(chip->dev); } } static const struct pwm_ops ecap_pwm_ops = { .free = ecap_pwm_free, .config = ecap_pwm_config, .set_polarity = ecap_pwm_set_polarity, .enable = ecap_pwm_enable, .disable = ecap_pwm_disable, .owner = THIS_MODULE, }; static int __devinit ecap_pwm_probe(struct platform_device *pdev) { int ret; struct resource *r; struct clk *clk; struct ecap_pwm_chip *pc; pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL); if (!pc) { dev_err(&pdev->dev, "failed to allocate memory\n"); return -ENOMEM; } clk = devm_clk_get(&pdev->dev, "fck"); if (IS_ERR(clk)) { dev_err(&pdev->dev, "failed to get clock\n"); return PTR_ERR(clk); } pc->clk_rate = clk_get_rate(clk); if (!pc->clk_rate) { dev_err(&pdev->dev, "failed to get clock rate\n"); return -EINVAL; } pc->chip.dev = &pdev->dev; pc->chip.ops = &ecap_pwm_ops; pc->chip.base = -1; pc->chip.npwm = 1; r = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!r) { dev_err(&pdev->dev, "no memory resource defined\n"); return -ENODEV; } pc->mmio_base = devm_request_and_ioremap(&pdev->dev, r); if (!pc->mmio_base) return -EADDRNOTAVAIL; ret = pwmchip_add(&pc->chip); if (ret < 0) { dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); return ret; } pm_runtime_enable(&pdev->dev); platform_set_drvdata(pdev, pc); return 0; } static int __devexit ecap_pwm_remove(struct platform_device *pdev) { struct ecap_pwm_chip *pc = platform_get_drvdata(pdev); pm_runtime_put_sync(&pdev->dev); pm_runtime_disable(&pdev->dev); return pwmchip_remove(&pc->chip); } static struct platform_driver ecap_pwm_driver = { .driver = { .name = "ecap", }, .probe = ecap_pwm_probe, .remove = __devexit_p(ecap_pwm_remove), }; module_platform_driver(ecap_pwm_driver); MODULE_DESCRIPTION("ECAP PWM driver"); MODULE_AUTHOR("Texas Instruments"); MODULE_LICENSE("GPL");