diff options
Diffstat (limited to 'drivers/pwm/pwm-fsl-ftm.c')
| -rw-r--r-- | drivers/pwm/pwm-fsl-ftm.c | 495 |
1 files changed, 495 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-fsl-ftm.c b/drivers/pwm/pwm-fsl-ftm.c new file mode 100644 index 000000000000..420169e96b5f --- /dev/null +++ b/drivers/pwm/pwm-fsl-ftm.c @@ -0,0 +1,495 @@ +/* + * Freescale FlexTimer Module (FTM) PWM Driver + * + * Copyright 2012-2013 Freescale Semiconductor, Inc. + * + * 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. + */ + +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> +#include <linux/slab.h> + +#define FTM_SC 0x00 +#define FTM_SC_CLK_MASK 0x3 +#define FTM_SC_CLK_SHIFT 3 +#define FTM_SC_CLK(c) (((c) + 1) << FTM_SC_CLK_SHIFT) +#define FTM_SC_PS_MASK 0x7 +#define FTM_SC_PS_SHIFT 0 + +#define FTM_CNT 0x04 +#define FTM_MOD 0x08 + +#define FTM_CSC_BASE 0x0C +#define FTM_CSC_MSB BIT(5) +#define FTM_CSC_MSA BIT(4) +#define FTM_CSC_ELSB BIT(3) +#define FTM_CSC_ELSA BIT(2) +#define FTM_CSC(_channel) (FTM_CSC_BASE + ((_channel) * 8)) + +#define FTM_CV_BASE 0x10 +#define FTM_CV(_channel) (FTM_CV_BASE + ((_channel) * 8)) + +#define FTM_CNTIN 0x4C +#define FTM_STATUS 0x50 + +#define FTM_MODE 0x54 +#define FTM_MODE_FTMEN BIT(0) +#define FTM_MODE_INIT BIT(2) +#define FTM_MODE_PWMSYNC BIT(3) + +#define FTM_SYNC 0x58 +#define FTM_OUTINIT 0x5C +#define FTM_OUTMASK 0x60 +#define FTM_COMBINE 0x64 +#define FTM_DEADTIME 0x68 +#define FTM_EXTTRIG 0x6C +#define FTM_POL 0x70 +#define FTM_FMS 0x74 +#define FTM_FILTER 0x78 +#define FTM_FLTCTRL 0x7C +#define FTM_QDCTRL 0x80 +#define FTM_CONF 0x84 +#define FTM_FLTPOL 0x88 +#define FTM_SYNCONF 0x8C +#define FTM_INVCTRL 0x90 +#define FTM_SWOCTRL 0x94 +#define FTM_PWMLOAD 0x98 + +enum fsl_pwm_clk { + FSL_PWM_CLK_SYS, + FSL_PWM_CLK_FIX, + FSL_PWM_CLK_EXT, + FSL_PWM_CLK_CNTEN, + FSL_PWM_CLK_MAX +}; + +struct fsl_pwm_chip { + struct pwm_chip chip; + + struct mutex lock; + + unsigned int use_count; + unsigned int cnt_select; + unsigned int clk_ps; + + void __iomem *base; + + int period_ns; + + struct clk *clk[FSL_PWM_CLK_MAX]; +}; + +static inline struct fsl_pwm_chip *to_fsl_chip(struct pwm_chip *chip) +{ + return container_of(chip, struct fsl_pwm_chip, chip); +} + +static int fsl_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct fsl_pwm_chip *fpc = to_fsl_chip(chip); + + return clk_prepare_enable(fpc->clk[FSL_PWM_CLK_SYS]); +} + +static void fsl_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct fsl_pwm_chip *fpc = to_fsl_chip(chip); + + clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_SYS]); +} + +static int fsl_pwm_calculate_default_ps(struct fsl_pwm_chip *fpc, + enum fsl_pwm_clk index) +{ + unsigned long sys_rate, cnt_rate; + unsigned long long ratio; + + sys_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_SYS]); + if (!sys_rate) + return -EINVAL; + + cnt_rate = clk_get_rate(fpc->clk[fpc->cnt_select]); + if (!cnt_rate) + return -EINVAL; + + switch (index) { + case FSL_PWM_CLK_SYS: + fpc->clk_ps = 1; + break; + case FSL_PWM_CLK_FIX: + ratio = 2 * cnt_rate - 1; + do_div(ratio, sys_rate); + fpc->clk_ps = ratio; + break; + case FSL_PWM_CLK_EXT: + ratio = 4 * cnt_rate - 1; + do_div(ratio, sys_rate); + fpc->clk_ps = ratio; + break; + default: + return -EINVAL; + } + + return 0; +} + +static unsigned long fsl_pwm_calculate_cycles(struct fsl_pwm_chip *fpc, + unsigned long period_ns) +{ + unsigned long long c, c0; + + c = clk_get_rate(fpc->clk[fpc->cnt_select]); + c = c * period_ns; + do_div(c, 1000000000UL); + + do { + c0 = c; + do_div(c0, (1 << fpc->clk_ps)); + if (c0 <= 0xFFFF) + return (unsigned long)c0; + } while (++fpc->clk_ps < 8); + + return 0; +} + +static unsigned long fsl_pwm_calculate_period_cycles(struct fsl_pwm_chip *fpc, + unsigned long period_ns, + enum fsl_pwm_clk index) +{ + int ret; + + ret = fsl_pwm_calculate_default_ps(fpc, index); + if (ret) { + dev_err(fpc->chip.dev, + "failed to calculate default prescaler: %d\n", + ret); + return 0; + } + + return fsl_pwm_calculate_cycles(fpc, period_ns); +} + +static unsigned long fsl_pwm_calculate_period(struct fsl_pwm_chip *fpc, + unsigned long period_ns) +{ + enum fsl_pwm_clk m0, m1; + unsigned long fix_rate, ext_rate, cycles; + + cycles = fsl_pwm_calculate_period_cycles(fpc, period_ns, + FSL_PWM_CLK_SYS); + if (cycles) { + fpc->cnt_select = FSL_PWM_CLK_SYS; + return cycles; + } + + fix_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_FIX]); + ext_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_EXT]); + + if (fix_rate > ext_rate) { + m0 = FSL_PWM_CLK_FIX; + m1 = FSL_PWM_CLK_EXT; + } else { + m0 = FSL_PWM_CLK_EXT; + m1 = FSL_PWM_CLK_FIX; + } + + cycles = fsl_pwm_calculate_period_cycles(fpc, period_ns, m0); + if (cycles) { + fpc->cnt_select = m0; + return cycles; + } + + fpc->cnt_select = m1; + + return fsl_pwm_calculate_period_cycles(fpc, period_ns, m1); +} + +static unsigned long fsl_pwm_calculate_duty(struct fsl_pwm_chip *fpc, + unsigned long period_ns, + unsigned long duty_ns) +{ + unsigned long long val, duty; + + val = readl(fpc->base + FTM_MOD); + duty = duty_ns * (val + 1); + do_div(duty, period_ns); + + return (unsigned long)duty; +} + +static int fsl_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct fsl_pwm_chip *fpc = to_fsl_chip(chip); + u32 val, period, duty; + + mutex_lock(&fpc->lock); + + /* + * The Freescale FTM controller supports only a single period for + * all PWM channels, therefore incompatible changes need to be + * refused. + */ + if (fpc->period_ns && fpc->period_ns != period_ns) { + dev_err(fpc->chip.dev, + "conflicting period requested for PWM %u\n", + pwm->hwpwm); + mutex_unlock(&fpc->lock); + return -EBUSY; + } + + if (!fpc->period_ns && duty_ns) { + period = fsl_pwm_calculate_period(fpc, period_ns); + if (!period) { + dev_err(fpc->chip.dev, "failed to calculate period\n"); + mutex_unlock(&fpc->lock); + return -EINVAL; + } + + val = readl(fpc->base + FTM_SC); + val &= ~(FTM_SC_PS_MASK << FTM_SC_PS_SHIFT); + val |= fpc->clk_ps; + writel(val, fpc->base + FTM_SC); + writel(period - 1, fpc->base + FTM_MOD); + + fpc->period_ns = period_ns; + } + + mutex_unlock(&fpc->lock); + + duty = fsl_pwm_calculate_duty(fpc, period_ns, duty_ns); + + writel(FTM_CSC_MSB | FTM_CSC_ELSB, fpc->base + FTM_CSC(pwm->hwpwm)); + writel(duty, fpc->base + FTM_CV(pwm->hwpwm)); + + return 0; +} + +static int fsl_pwm_set_polarity(struct pwm_chip *chip, + struct pwm_device *pwm, + enum pwm_polarity polarity) +{ + struct fsl_pwm_chip *fpc = to_fsl_chip(chip); + u32 val; + + val = readl(fpc->base + FTM_POL); + + if (polarity == PWM_POLARITY_INVERSED) + val |= BIT(pwm->hwpwm); + else + val &= ~BIT(pwm->hwpwm); + + writel(val, fpc->base + FTM_POL); + + return 0; +} + +static int fsl_counter_clock_enable(struct fsl_pwm_chip *fpc) +{ + u32 val; + int ret; + + if (fpc->use_count != 0) + return 0; + + /* select counter clock source */ + val = readl(fpc->base + FTM_SC); + val &= ~(FTM_SC_CLK_MASK << FTM_SC_CLK_SHIFT); + val |= FTM_SC_CLK(fpc->cnt_select); + writel(val, fpc->base + FTM_SC); + + ret = clk_prepare_enable(fpc->clk[fpc->cnt_select]); + if (ret) + return ret; + + ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]); + if (ret) { + clk_disable_unprepare(fpc->clk[fpc->cnt_select]); + return ret; + } + + fpc->use_count++; + + return 0; +} + +static int fsl_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct fsl_pwm_chip *fpc = to_fsl_chip(chip); + u32 val; + int ret; + + mutex_lock(&fpc->lock); + val = readl(fpc->base + FTM_OUTMASK); + val &= ~BIT(pwm->hwpwm); + writel(val, fpc->base + FTM_OUTMASK); + + ret = fsl_counter_clock_enable(fpc); + mutex_unlock(&fpc->lock); + + return ret; +} + +static void fsl_counter_clock_disable(struct fsl_pwm_chip *fpc) +{ + u32 val; + + /* + * already disabled, do nothing + */ + if (fpc->use_count == 0) + return; + + /* there are still users, so can't disable yet */ + if (--fpc->use_count > 0) + return; + + /* no users left, disable PWM counter clock */ + val = readl(fpc->base + FTM_SC); + val &= ~(FTM_SC_CLK_MASK << FTM_SC_CLK_SHIFT); + writel(val, fpc->base + FTM_SC); + + clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]); + clk_disable_unprepare(fpc->clk[fpc->cnt_select]); +} + +static void fsl_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct fsl_pwm_chip *fpc = to_fsl_chip(chip); + u32 val; + + mutex_lock(&fpc->lock); + val = readl(fpc->base + FTM_OUTMASK); + val |= BIT(pwm->hwpwm); + writel(val, fpc->base + FTM_OUTMASK); + + fsl_counter_clock_disable(fpc); + + val = readl(fpc->base + FTM_OUTMASK); + + if ((val & 0xFF) == 0xFF) + fpc->period_ns = 0; + + mutex_unlock(&fpc->lock); +} + +static const struct pwm_ops fsl_pwm_ops = { + .request = fsl_pwm_request, + .free = fsl_pwm_free, + .config = fsl_pwm_config, + .set_polarity = fsl_pwm_set_polarity, + .enable = fsl_pwm_enable, + .disable = fsl_pwm_disable, + .owner = THIS_MODULE, +}; + +static int fsl_pwm_init(struct fsl_pwm_chip *fpc) +{ + int ret; + + ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_SYS]); + if (ret) + return ret; + + writel(0x00, fpc->base + FTM_CNTIN); + writel(0x00, fpc->base + FTM_OUTINIT); + writel(0xFF, fpc->base + FTM_OUTMASK); + + clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_SYS]); + + return 0; +} + +static int fsl_pwm_probe(struct platform_device *pdev) +{ + struct fsl_pwm_chip *fpc; + struct resource *res; + int ret; + + fpc = devm_kzalloc(&pdev->dev, sizeof(*fpc), GFP_KERNEL); + if (!fpc) + return -ENOMEM; + + mutex_init(&fpc->lock); + + fpc->chip.dev = &pdev->dev; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + fpc->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(fpc->base)) + return PTR_ERR(fpc->base); + + fpc->clk[FSL_PWM_CLK_SYS] = devm_clk_get(&pdev->dev, "ftm_sys"); + if (IS_ERR(fpc->clk[FSL_PWM_CLK_SYS])) { + dev_err(&pdev->dev, "failed to get \"ftm_sys\" clock\n"); + return PTR_ERR(fpc->clk[FSL_PWM_CLK_SYS]); + } + + fpc->clk[FSL_PWM_CLK_FIX] = devm_clk_get(fpc->chip.dev, "ftm_fix"); + if (IS_ERR(fpc->clk[FSL_PWM_CLK_FIX])) + return PTR_ERR(fpc->clk[FSL_PWM_CLK_FIX]); + + fpc->clk[FSL_PWM_CLK_EXT] = devm_clk_get(fpc->chip.dev, "ftm_ext"); + if (IS_ERR(fpc->clk[FSL_PWM_CLK_EXT])) + return PTR_ERR(fpc->clk[FSL_PWM_CLK_EXT]); + + fpc->clk[FSL_PWM_CLK_CNTEN] = + devm_clk_get(fpc->chip.dev, "ftm_cnt_clk_en"); + if (IS_ERR(fpc->clk[FSL_PWM_CLK_CNTEN])) + return PTR_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]); + + fpc->chip.ops = &fsl_pwm_ops; + fpc->chip.of_xlate = of_pwm_xlate_with_flags; + fpc->chip.of_pwm_n_cells = 3; + fpc->chip.base = -1; + fpc->chip.npwm = 8; + + ret = pwmchip_add(&fpc->chip); + if (ret < 0) { + dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret); + return ret; + } + + platform_set_drvdata(pdev, fpc); + + return fsl_pwm_init(fpc); +} + +static int fsl_pwm_remove(struct platform_device *pdev) +{ + struct fsl_pwm_chip *fpc = platform_get_drvdata(pdev); + + return pwmchip_remove(&fpc->chip); +} + +static const struct of_device_id fsl_pwm_dt_ids[] = { + { .compatible = "fsl,vf610-ftm-pwm", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, fsl_pwm_dt_ids); + +static struct platform_driver fsl_pwm_driver = { + .driver = { + .name = "fsl-ftm-pwm", + .of_match_table = fsl_pwm_dt_ids, + }, + .probe = fsl_pwm_probe, + .remove = fsl_pwm_remove, +}; +module_platform_driver(fsl_pwm_driver); + +MODULE_DESCRIPTION("Freescale FlexTimer Module PWM Driver"); +MODULE_AUTHOR("Xiubo Li <Li.Xiubo@freescale.com>"); +MODULE_ALIAS("platform:fsl-ftm-pwm"); +MODULE_LICENSE("GPL"); |