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Release 4.14 drivers/pwm/pwm-atmel-tcb.c

Directory: drivers/pwm
/*
 * Copyright (C) Overkiz SAS 2012
 *
 * Author: Boris BREZILLON <b.brezillon@overkiz.com>
 * License terms: GNU General Public License (GPL) version 2
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/irq.h>

#include <linux/clk.h>
#include <linux/err.h>
#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/atmel_tc.h>
#include <linux/pwm.h>
#include <linux/of_device.h>
#include <linux/slab.h>


#define NPWM	6


#define ATMEL_TC_ACMR_MASK	(ATMEL_TC_ACPA | ATMEL_TC_ACPC |        \
                                 ATMEL_TC_AEEVT | ATMEL_TC_ASWTRG)


#define ATMEL_TC_BCMR_MASK	(ATMEL_TC_BCPB | ATMEL_TC_BCPC |        \
                                 ATMEL_TC_BEEVT | ATMEL_TC_BSWTRG)


struct atmel_tcb_pwm_device {
	
enum pwm_polarity polarity;	/* PWM polarity */
	
unsigned div;			/* PWM clock divider */
	
unsigned duty;			/* PWM duty expressed in clk cycles */
	
unsigned period;		/* PWM period expressed in clk cycles */
};


struct atmel_tcb_pwm_chip {
	
struct pwm_chip chip;
	
spinlock_t lock;
	
struct atmel_tc *tc;
	
struct atmel_tcb_pwm_device *pwms[NPWM];
};


static inline struct atmel_tcb_pwm_chip *to_tcb_chip(struct pwm_chip *chip) { return container_of(chip, struct atmel_tcb_pwm_chip, chip); }

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static int atmel_tcb_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, enum pwm_polarity polarity) { struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); tcbpwm->polarity = polarity; return 0; }

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static int atmel_tcb_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) { struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); struct atmel_tcb_pwm_device *tcbpwm; struct atmel_tc *tc = tcbpwmc->tc; void __iomem *regs = tc->regs; unsigned group = pwm->hwpwm / 2; unsigned index = pwm->hwpwm % 2; unsigned cmr; int ret; tcbpwm = devm_kzalloc(chip->dev, sizeof(*tcbpwm), GFP_KERNEL); if (!tcbpwm) return -ENOMEM; ret = clk_prepare_enable(tc->clk[group]); if (ret) { devm_kfree(chip->dev, tcbpwm); return ret; } pwm_set_chip_data(pwm, tcbpwm); tcbpwm->polarity = PWM_POLARITY_NORMAL; tcbpwm->duty = 0; tcbpwm->period = 0; tcbpwm->div = 0; spin_lock(&tcbpwmc->lock); cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR)); /* * Get init config from Timer Counter registers if * Timer Counter is already configured as a PWM generator. */ if (cmr & ATMEL_TC_WAVE) { if (index == 0) tcbpwm->duty = __raw_readl(regs + ATMEL_TC_REG(group, RA)); else tcbpwm->duty = __raw_readl(regs + ATMEL_TC_REG(group, RB)); tcbpwm->div = cmr & ATMEL_TC_TCCLKS; tcbpwm->period = __raw_readl(regs + ATMEL_TC_REG(group, RC)); cmr &= (ATMEL_TC_TCCLKS | ATMEL_TC_ACMR_MASK | ATMEL_TC_BCMR_MASK); } else cmr = 0; cmr |= ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO | ATMEL_TC_EEVT_XC0; __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR)); spin_unlock(&tcbpwmc->lock); tcbpwmc->pwms[pwm->hwpwm] = tcbpwm; return 0; }

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static void atmel_tcb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) { struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); struct atmel_tc *tc = tcbpwmc->tc; clk_disable_unprepare(tc->clk[pwm->hwpwm / 2]); tcbpwmc->pwms[pwm->hwpwm] = NULL; devm_kfree(chip->dev, tcbpwm); }

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static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) { struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); struct atmel_tc *tc = tcbpwmc->tc; void __iomem *regs = tc->regs; unsigned group = pwm->hwpwm / 2; unsigned index = pwm->hwpwm % 2; unsigned cmr; enum pwm_polarity polarity = tcbpwm->polarity; /* * If duty is 0 the timer will be stopped and we have to * configure the output correctly on software trigger: * - set output to high if PWM_POLARITY_INVERSED * - set output to low if PWM_POLARITY_NORMAL * * This is why we're reverting polarity in this case. */ if (tcbpwm->duty == 0) polarity = !polarity; spin_lock(&tcbpwmc->lock); cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR)); /* flush old setting and set the new one */ if (index == 0) { cmr &= ~ATMEL_TC_ACMR_MASK; if (polarity == PWM_POLARITY_INVERSED) cmr |= ATMEL_TC_ASWTRG_CLEAR; else cmr |= ATMEL_TC_ASWTRG_SET; } else { cmr &= ~ATMEL_TC_BCMR_MASK; if (polarity == PWM_POLARITY_INVERSED) cmr |= ATMEL_TC_BSWTRG_CLEAR; else cmr |= ATMEL_TC_BSWTRG_SET; } __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR)); /* * Use software trigger to apply the new setting. * If both PWM devices in this group are disabled we stop the clock. */ if (!(cmr & (ATMEL_TC_ACPC | ATMEL_TC_BCPC))) __raw_writel(ATMEL_TC_SWTRG | ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(group, CCR)); else __raw_writel(ATMEL_TC_SWTRG, regs + ATMEL_TC_REG(group, CCR)); spin_unlock(&tcbpwmc->lock); }

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static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) { struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); struct atmel_tc *tc = tcbpwmc->tc; void __iomem *regs = tc->regs; unsigned group = pwm->hwpwm / 2; unsigned index = pwm->hwpwm % 2; u32 cmr; enum pwm_polarity polarity = tcbpwm->polarity; /* * If duty is 0 the timer will be stopped and we have to * configure the output correctly on software trigger: * - set output to high if PWM_POLARITY_INVERSED * - set output to low if PWM_POLARITY_NORMAL * * This is why we're reverting polarity in this case. */ if (tcbpwm->duty == 0) polarity = !polarity; spin_lock(&tcbpwmc->lock); cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR)); /* flush old setting and set the new one */ cmr &= ~ATMEL_TC_TCCLKS; if (index == 0) { cmr &= ~ATMEL_TC_ACMR_MASK; /* Set CMR flags according to given polarity */ if (polarity == PWM_POLARITY_INVERSED) cmr |= ATMEL_TC_ASWTRG_CLEAR; else cmr |= ATMEL_TC_ASWTRG_SET; } else { cmr &= ~ATMEL_TC_BCMR_MASK; if (polarity == PWM_POLARITY_INVERSED) cmr |= ATMEL_TC_BSWTRG_CLEAR; else cmr |= ATMEL_TC_BSWTRG_SET; } /* * If duty is 0 or equal to period there's no need to register * a specific action on RA/RB and RC compare. * The output will be configured on software trigger and keep * this config till next config call. */ if (tcbpwm->duty != tcbpwm->period && tcbpwm->duty > 0) { if (index == 0) { if (polarity == PWM_POLARITY_INVERSED) cmr |= ATMEL_TC_ACPA_SET | ATMEL_TC_ACPC_CLEAR; else cmr |= ATMEL_TC_ACPA_CLEAR | ATMEL_TC_ACPC_SET; } else { if (polarity == PWM_POLARITY_INVERSED) cmr |= ATMEL_TC_BCPB_SET | ATMEL_TC_BCPC_CLEAR; else cmr |= ATMEL_TC_BCPB_CLEAR | ATMEL_TC_BCPC_SET; } } cmr |= (tcbpwm->div & ATMEL_TC_TCCLKS); __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR)); if (index == 0) __raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RA)); else __raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RB)); __raw_writel(tcbpwm->period, regs + ATMEL_TC_REG(group, RC)); /* Use software trigger to apply the new setting */ __raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG, regs + ATMEL_TC_REG(group, CCR)); spin_unlock(&tcbpwmc->lock); return 0; }

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static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns) { struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); unsigned group = pwm->hwpwm / 2; unsigned index = pwm->hwpwm % 2; struct atmel_tcb_pwm_device *atcbpwm = NULL; struct atmel_tc *tc = tcbpwmc->tc; int i; int slowclk = 0; unsigned period; unsigned duty; unsigned rate = clk_get_rate(tc->clk[group]); unsigned long long min; unsigned long long max; /* * Find best clk divisor: * the smallest divisor which can fulfill the period_ns requirements. */ for (i = 0; i < 5; ++i) { if (atmel_tc_divisors[i] == 0) { slowclk = i; continue; } min = div_u64((u64)NSEC_PER_SEC * atmel_tc_divisors[i], rate); max = min << tc->tcb_config->counter_width; if (max >= period_ns) break; } /* * If none of the divisor are small enough to represent period_ns * take slow clock (32KHz). */ if (i == 5) { i = slowclk; rate = clk_get_rate(tc->slow_clk); min = div_u64(NSEC_PER_SEC, rate); max = min << tc->tcb_config->counter_width; /* If period is too big return ERANGE error */ if (max < period_ns) return -ERANGE; } duty = div_u64(duty_ns, min); period = div_u64(period_ns, min); if (index == 0) atcbpwm = tcbpwmc->pwms[pwm->hwpwm + 1]; else atcbpwm = tcbpwmc->pwms[pwm->hwpwm - 1]; /* * PWM devices provided by TCB driver are grouped by 2: * - group 0: PWM 0 & 1 * - group 1: PWM 2 & 3 * - group 2: PWM 4 & 5 * * PWM devices in a given group must be configured with the * same period_ns. * * We're checking the period value of the second PWM device * in this group before applying the new config. */ if ((atcbpwm && atcbpwm->duty > 0 && atcbpwm->duty != atcbpwm->period) && (atcbpwm->div != i || atcbpwm->period != period)) { dev_err(chip->dev, "failed to configure period_ns: PWM group already configured with a different value\n"); return -EINVAL; } tcbpwm->period = period; tcbpwm->div = i; tcbpwm->duty = duty; /* If the PWM is enabled, call enable to apply the new conf */ if (pwm_is_enabled(pwm)) atmel_tcb_pwm_enable(chip, pwm); return 0; }

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static const struct pwm_ops atmel_tcb_pwm_ops = { .request = atmel_tcb_pwm_request, .free = atmel_tcb_pwm_free, .config = atmel_tcb_pwm_config, .set_polarity = atmel_tcb_pwm_set_polarity, .enable = atmel_tcb_pwm_enable, .disable = atmel_tcb_pwm_disable, .owner = THIS_MODULE, };
static int atmel_tcb_pwm_probe(struct platform_device *pdev) { struct atmel_tcb_pwm_chip *tcbpwm; struct device_node *np = pdev->dev.of_node; struct atmel_tc *tc; int err; int tcblock; err = of_property_read_u32(np, "tc-block", &tcblock); if (err < 0) { dev_err(&pdev->dev, "failed to get Timer Counter Block number from device tree (error: %d)\n", err); return err; } tc = atmel_tc_alloc(tcblock); if (tc == NULL) { dev_err(&pdev->dev, "failed to allocate Timer Counter Block\n"); return -ENOMEM; } tcbpwm = devm_kzalloc(&pdev->dev, sizeof(*tcbpwm), GFP_KERNEL); if (tcbpwm == NULL) { err = -ENOMEM; dev_err(&pdev->dev, "failed to allocate memory\n"); goto err_free_tc; } tcbpwm->chip.dev = &pdev->dev; tcbpwm->chip.ops = &atmel_tcb_pwm_ops; tcbpwm->chip.of_xlate = of_pwm_xlate_with_flags; tcbpwm->chip.of_pwm_n_cells = 3; tcbpwm->chip.base = -1; tcbpwm->chip.npwm = NPWM; tcbpwm->tc = tc; err = clk_prepare_enable(tc->slow_clk); if (err) goto err_free_tc; spin_lock_init(&tcbpwm->lock); err = pwmchip_add(&tcbpwm->chip); if (err < 0) goto err_disable_clk; platform_set_drvdata(pdev, tcbpwm); return 0; err_disable_clk: clk_disable_unprepare(tcbpwm->tc->slow_clk); err_free_tc: atmel_tc_free(tc); return err; }

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static int atmel_tcb_pwm_remove(struct platform_device *pdev) { struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev); int err; clk_disable_unprepare(tcbpwm->tc->slow_clk); err = pwmchip_remove(&tcbpwm->chip); if (err < 0) return err; atmel_tc_free(tcbpwm->tc); return 0; }

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static const struct of_device_id atmel_tcb_pwm_dt_ids[] = { { .compatible = "atmel,tcb-pwm", }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, atmel_tcb_pwm_dt_ids); static struct platform_driver atmel_tcb_pwm_driver = { .driver = { .name = "atmel-tcb-pwm", .of_match_table = atmel_tcb_pwm_dt_ids, }, .probe = atmel_tcb_pwm_probe, .remove = atmel_tcb_pwm_remove, }; module_platform_driver(atmel_tcb_pwm_driver); MODULE_AUTHOR("Boris BREZILLON <b.brezillon@overkiz.com>"); MODULE_DESCRIPTION("Atmel Timer Counter Pulse Width Modulation Driver"); MODULE_LICENSE("GPL v2");

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Directory: drivers/pwm
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