diff options
author | Lee Jones <lee.jones@linaro.org> | 2016-08-16 10:35:07 +0100 |
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committer | Thierry Reding <thierry.reding@gmail.com> | 2016-09-08 10:55:12 +0200 |
commit | 7d8a600c916cab347662de212340d3eaf0e93db2 (patch) | |
tree | f3c29f24517810af259f03d1dee1e93663179677 /drivers/pwm/pwm-sti.c | |
parent | 85a834c42a491deed9ac5bca549b93b7a5455d84 (diff) | |
download | linux-next-7d8a600c916cab347662de212340d3eaf0e93db2.tar.gz |
pwm: sti: Take the opportunity to conduct a little house keeping
This includes fixing some Coding Style issues and re-ordering and/or
simplifying a little code.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
[thierry.reding@gmail.com: applied some bikeshedding>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm/pwm-sti.c')
-rw-r--r-- | drivers/pwm/pwm-sti.c | 153 |
1 files changed, 81 insertions, 72 deletions
diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c index 9a1ca1986c30..dd82dc840af9 100644 --- a/drivers/pwm/pwm-sti.c +++ b/drivers/pwm/pwm-sti.c @@ -1,8 +1,10 @@ /* - * PWM device driver for ST SoCs. - * Author: Ajit Pal Singh <ajitpal.singh@st.com> + * PWM device driver for ST SoCs + * + * Copyright (C) 2013-2016 STMicroelectronics (R&D) Limited * - * Copyright (C) 2013-2014 STMicroelectronics (R&D) Limited + * Author: Ajit Pal Singh <ajitpal.singh@st.com> + * Lee Jones <lee.jones@linaro.org> * * 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 @@ -31,14 +33,14 @@ #define STI_PWM_CTRL 0x50 /* Control/Config register */ #define STI_INT_EN 0x54 /* Interrupt Enable/Disable register */ #define STI_INT_STA 0x58 /* Interrupt Status register */ -#define PWM_INT_ACK 0x5c -#define PWM_PRESCALE_LOW_MASK 0x0f -#define PWM_PRESCALE_HIGH_MASK 0xf0 -#define PWM_CPT_EDGE_MASK 0x03 -#define PWM_INT_ACK_MASK 0x1ff +#define PWM_INT_ACK 0x5c +#define PWM_PRESCALE_LOW_MASK 0x0f +#define PWM_PRESCALE_HIGH_MASK 0xf0 +#define PWM_CPT_EDGE_MASK 0x03 +#define PWM_INT_ACK_MASK 0x1ff -#define STI_MAX_CPT_DEVS 4 -#define CPT_DC_MAX 0xff +#define STI_MAX_CPT_DEVS 4 +#define CPT_DC_MAX 0xff /* Regfield IDs */ enum { @@ -57,8 +59,9 @@ enum { MAX_REGFIELDS }; -/* Each capture input can be programmed to detect rising-edge, falling-edge, - * either edge or neither egde +/* + * Each capture input can be programmed to detect rising-edge, falling-edge, + * either edge or neither egde. */ enum sti_cpt_edge { CPT_EDGE_DISABLED, @@ -103,13 +106,13 @@ struct sti_pwm_chip { }; static const struct reg_field sti_pwm_regfields[MAX_REGFIELDS] = { - [PWMCLK_PRESCALE_LOW] = REG_FIELD(STI_PWM_CTRL, 0, 3), - [PWMCLK_PRESCALE_HIGH] = REG_FIELD(STI_PWM_CTRL, 11, 14), - [CPTCLK_PRESCALE] = REG_FIELD(STI_PWM_CTRL, 4, 8), - [PWM_OUT_EN] = REG_FIELD(STI_PWM_CTRL, 9, 9), - [PWM_CPT_EN] = REG_FIELD(STI_PWM_CTRL, 10, 10), - [PWM_CPT_INT_EN] = REG_FIELD(STI_INT_EN, 1, 4), - [PWM_CPT_INT_STAT] = REG_FIELD(STI_INT_STA, 1, 4), + [PWMCLK_PRESCALE_LOW] = REG_FIELD(STI_PWM_CTRL, 0, 3), + [PWMCLK_PRESCALE_HIGH] = REG_FIELD(STI_PWM_CTRL, 11, 14), + [CPTCLK_PRESCALE] = REG_FIELD(STI_PWM_CTRL, 4, 8), + [PWM_OUT_EN] = REG_FIELD(STI_PWM_CTRL, 9, 9), + [PWM_CPT_EN] = REG_FIELD(STI_PWM_CTRL, 10, 10), + [PWM_CPT_INT_EN] = REG_FIELD(STI_INT_EN, 1, 4), + [PWM_CPT_INT_STAT] = REG_FIELD(STI_INT_STA, 1, 4), }; static inline struct sti_pwm_chip *to_sti_pwmchip(struct pwm_chip *chip) @@ -125,7 +128,7 @@ static int sti_pwm_get_prescale(struct sti_pwm_chip *pc, unsigned long period, { struct sti_pwm_compat_data *cdata = pc->cdata; unsigned long clk_rate; - unsigned long val; + unsigned long value; unsigned int ps; clk_rate = clk_get_rate(pc->pwm_clk); @@ -135,56 +138,56 @@ static int sti_pwm_get_prescale(struct sti_pwm_chip *pc, unsigned long period, } /* - * prescale = ((period_ns * clk_rate) / (10^9 * (max_pwm_count + 1)) - 1 + * prescale = ((period_ns * clk_rate) / (10^9 * (max_pwm_cnt + 1)) - 1 */ - val = NSEC_PER_SEC / clk_rate; - val *= cdata->max_pwm_cnt + 1; + value = NSEC_PER_SEC / clk_rate; + value *= cdata->max_pwm_cnt + 1; - if (period % val) { + if (period % value) return -EINVAL; - } else { - ps = period / val - 1; - if (ps > cdata->max_prescale) - return -EINVAL; - } + + ps = period / value - 1; + if (ps > cdata->max_prescale) + return -EINVAL; + *prescale = ps; return 0; } /* - * For STiH4xx PWM IP, the PWM period is fixed to 256 local clock cycles. - * The only way to change the period (apart from changing the PWM input clock) - * is to change the PWM clock prescaler. - * The prescaler is of 8 bits, so 256 prescaler values and hence - * 256 possible period values are supported (for a particular clock rate). - * The requested period will be applied only if it matches one of these - * 256 values. + * For STiH4xx PWM IP, the PWM period is fixed to 256 local clock cycles. The + * only way to change the period (apart from changing the PWM input clock) is + * to change the PWM clock prescaler. + * + * The prescaler is of 8 bits, so 256 prescaler values and hence 256 possible + * period values are supported (for a particular clock rate). The requested + * period will be applied only if it matches one of these 256 values. */ static int sti_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, - int duty_ns, int period_ns) + int duty_ns, int period_ns) { struct sti_pwm_chip *pc = to_sti_pwmchip(chip); struct sti_pwm_compat_data *cdata = pc->cdata; + unsigned int ncfg, value, prescale = 0; struct pwm_device *cur = pc->cur; struct device *dev = pc->dev; - unsigned int prescale = 0, pwmvalx; - int ret; - unsigned int ncfg; bool period_same = false; + int ret; ncfg = hweight_long(pc->configured); if (ncfg) period_same = (period_ns == pwm_get_period(cur)); - /* Allow configuration changes if one of the - * following conditions satisfy. + /* + * Allow configuration changes if one of the following conditions + * satisfy. * 1. No devices have been configured. - * 2. Only one device has been configured and the new request - * is for the same device. - * 3. Only one device has been configured and the new request is - * for a new device and period of the new device is same as - * the current configured period. + * 2. Only one device has been configured and the new request is for + * the same device. + * 3. Only one device has been configured and the new request is for + * a new device and period of the new device is same as the current + * configured period. * 4. More than one devices are configured and period of the new * requestis the same as the current period. */ @@ -206,15 +209,15 @@ static int sti_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, if (ret) goto clk_dis; - ret = - regmap_field_write(pc->prescale_low, - prescale & PWM_PRESCALE_LOW_MASK); + value = prescale & PWM_PRESCALE_LOW_MASK; + + ret = regmap_field_write(pc->prescale_low, value); if (ret) goto clk_dis; - ret = - regmap_field_write(pc->prescale_high, - (prescale & PWM_PRESCALE_HIGH_MASK) >> 4); + value = (prescale & PWM_PRESCALE_HIGH_MASK) >> 4; + + ret = regmap_field_write(pc->prescale_high, value); if (ret) goto clk_dis; } @@ -225,10 +228,9 @@ static int sti_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, * PWM pulse = (max_pwm_count + 1) local cycles, * that is continuous pulse: signal never goes low. */ - pwmvalx = cdata->max_pwm_cnt * duty_ns / period_ns; + value = cdata->max_pwm_cnt * duty_ns / period_ns; - ret = regmap_write(pc->regmap, - PWM_OUT_VAL(pwm->hwpwm), pwmvalx); + ret = regmap_write(pc->regmap, PWM_OUT_VAL(pwm->hwpwm), value); if (ret) goto clk_dis; @@ -237,8 +239,8 @@ static int sti_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, set_bit(pwm->hwpwm, &pc->configured); pc->cur = pwm; - dev_dbg(dev, "prescale:%u, period:%i, duty:%i, pwmvalx:%u\n", - prescale, period_ns, duty_ns, pwmvalx); + dev_dbg(dev, "prescale:%u, period:%i, duty:%i, value:%u\n", + prescale, period_ns, duty_ns, value); } else { return -EINVAL; } @@ -256,10 +258,11 @@ static int sti_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) int ret = 0; /* - * Since we have a common enable for all PWM devices, - * do not enable if already enabled. + * Since we have a common enable for all PWM devices, do not enable if + * already enabled. */ mutex_lock(&pc->sti_pwm_lock); + if (!pc->en_count) { ret = clk_enable(pc->pwm_clk); if (ret) @@ -271,12 +274,14 @@ static int sti_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) ret = regmap_field_write(pc->pwm_out_en, 1); if (ret) { - dev_err(dev, "failed to enable PWM device:%d\n", - pwm->hwpwm); + dev_err(dev, "failed to enable PWM device %u: %d\n", + pwm->hwpwm, ret); goto out; } } + pc->en_count++; + out: mutex_unlock(&pc->sti_pwm_lock); return ret; @@ -287,14 +292,17 @@ static void sti_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) struct sti_pwm_chip *pc = to_sti_pwmchip(chip); mutex_lock(&pc->sti_pwm_lock); + if (--pc->en_count) { mutex_unlock(&pc->sti_pwm_lock); return; } + regmap_field_write(pc->pwm_out_en, 0); clk_disable(pc->pwm_clk); clk_disable(pc->cpt_clk); + mutex_unlock(&pc->sti_pwm_lock); } @@ -422,14 +430,13 @@ static irqreturn_t sti_pwm_interrupt(int irq, void *data) * __| |_________________| |________ * ^0 ^1 ^2 * - * Capture start by the first available rising edge - * When a capture event occurs, capture value (CPT_VALx) - * is stored, index incremented, capture edge changed. - * - * After the capture, if the index > 1, we have collected - * the necessary data so we signal the thread waiting for it - * and disable the capture by setting capture edge to none + * Capture start by the first available rising edge. When a + * capture event occurs, capture value (CPT_VALx) is stored, + * index incremented, capture edge changed. * + * After the capture, if the index > 1, we have collected the + * necessary data so we signal the thread waiting for it and + * disable the capture by setting capture edge to none */ regmap_read(pc->regmap, @@ -445,12 +452,14 @@ static irqreturn_t sti_pwm_interrupt(int irq, void *data) ddata->index++; break; + case 2: regmap_write(pc->regmap, PWM_CPT_EDGE(devicenum), CPT_EDGE_DISABLED); wake_up(&ddata->wait); break; + default: dev_err(dev, "Internal error\n"); } @@ -512,7 +521,7 @@ static int sti_pwm_probe_dt(struct sti_pwm_chip *pc) return PTR_ERR(pc->pwm_cpt_en); pc->pwm_cpt_int_en = devm_regmap_field_alloc(dev, pc->regmap, - reg_fields[PWM_CPT_INT_EN]); + reg_fields[PWM_CPT_INT_EN]); if (IS_ERR(pc->pwm_cpt_int_en)) return PTR_ERR(pc->pwm_cpt_int_en); @@ -575,9 +584,9 @@ static int sti_pwm_probe(struct platform_device *pdev) * Setup PWM data with default values: some values could be replaced * with specific ones provided from Device Tree. */ - cdata->reg_fields = &sti_pwm_regfields[0]; + cdata->reg_fields = sti_pwm_regfields; cdata->max_prescale = 0xff; - cdata->max_pwm_cnt = 255; + cdata->max_pwm_cnt = 255; cdata->pwm_num_devs = 0; cdata->cpt_num_devs = 0; |