diff options
Diffstat (limited to 'kernel/drivers/pwm/pwm-atmel-tcb.c')
| -rw-r--r-- | kernel/drivers/pwm/pwm-atmel-tcb.c | 448 |
1 files changed, 448 insertions, 0 deletions
diff --git a/kernel/drivers/pwm/pwm-atmel-tcb.c b/kernel/drivers/pwm/pwm-atmel-tcb.c new file mode 100644 index 000000000..d14e0677c --- /dev/null +++ b/kernel/drivers/pwm/pwm-atmel-tcb.c @@ -0,0 +1,448 @@ +/* + * 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); +} + +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; +} + +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; +} + +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); +} + +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); +} + +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; +} + +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 = 32768; + 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 (test_bit(PWMF_ENABLED, &pwm->flags)) + atmel_tcb_pwm_enable(chip, pwm); + + return 0; +} + +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) { + atmel_tc_free(tc); + dev_err(&pdev->dev, "failed to allocate memory\n"); + return -ENOMEM; + } + + 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; + + spin_lock_init(&tcbpwm->lock); + + err = pwmchip_add(&tcbpwm->chip); + if (err < 0) { + atmel_tc_free(tc); + return err; + } + + platform_set_drvdata(pdev, tcbpwm); + + return 0; +} + +static int atmel_tcb_pwm_remove(struct platform_device *pdev) +{ + struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev); + int err; + + err = pwmchip_remove(&tcbpwm->chip); + if (err < 0) + return err; + + atmel_tc_free(tcbpwm->tc); + + return 0; +} + +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"); |