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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>
This commit is contained in:
Lee Jones 2016-08-16 10:35:07 +01:00 committed by Thierry Reding
parent 85a834c42a
commit 7d8a600c91
1 changed files with 81 additions and 72 deletions
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153
drivers/pwm/pwm-sti.c
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@ -1,8 +1,10 @@
/* /*
* PWM device driver for ST SoCs. * PWM device driver for ST SoCs
* Author: Ajit Pal Singh <ajitpal.singh@st.com>
* *
* Copyright (C) 2013-2014 STMicroelectronics (R&D) Limited * Copyright (C) 2013-2016 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 * 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 * 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_PWM_CTRL 0x50 /* Control/Config register */
#define STI_INT_EN 0x54 /* Interrupt Enable/Disable register */ #define STI_INT_EN 0x54 /* Interrupt Enable/Disable register */
#define STI_INT_STA 0x58 /* Interrupt Status register */ #define STI_INT_STA 0x58 /* Interrupt Status register */
#define PWM_INT_ACK 0x5c #define PWM_INT_ACK 0x5c
#define PWM_PRESCALE_LOW_MASK 0x0f #define PWM_PRESCALE_LOW_MASK 0x0f
#define PWM_PRESCALE_HIGH_MASK 0xf0 #define PWM_PRESCALE_HIGH_MASK 0xf0
#define PWM_CPT_EDGE_MASK 0x03 #define PWM_CPT_EDGE_MASK 0x03
#define PWM_INT_ACK_MASK 0x1ff #define PWM_INT_ACK_MASK 0x1ff
#define STI_MAX_CPT_DEVS 4 #define STI_MAX_CPT_DEVS 4
#define CPT_DC_MAX 0xff #define CPT_DC_MAX 0xff
/* Regfield IDs */ /* Regfield IDs */
enum { enum {
@ -57,8 +59,9 @@ enum {
MAX_REGFIELDS 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 { enum sti_cpt_edge {
CPT_EDGE_DISABLED, CPT_EDGE_DISABLED,
@ -103,13 +106,13 @@ struct sti_pwm_chip {
}; };
static const struct reg_field sti_pwm_regfields[MAX_REGFIELDS] = { static const struct reg_field sti_pwm_regfields[MAX_REGFIELDS] = {
[PWMCLK_PRESCALE_LOW] = REG_FIELD(STI_PWM_CTRL, 0, 3), [PWMCLK_PRESCALE_LOW] = REG_FIELD(STI_PWM_CTRL, 0, 3),
[PWMCLK_PRESCALE_HIGH] = REG_FIELD(STI_PWM_CTRL, 11, 14), [PWMCLK_PRESCALE_HIGH] = REG_FIELD(STI_PWM_CTRL, 11, 14),
[CPTCLK_PRESCALE] = REG_FIELD(STI_PWM_CTRL, 4, 8), [CPTCLK_PRESCALE] = REG_FIELD(STI_PWM_CTRL, 4, 8),
[PWM_OUT_EN] = REG_FIELD(STI_PWM_CTRL, 9, 9), [PWM_OUT_EN] = REG_FIELD(STI_PWM_CTRL, 9, 9),
[PWM_CPT_EN] = REG_FIELD(STI_PWM_CTRL, 10, 10), [PWM_CPT_EN] = REG_FIELD(STI_PWM_CTRL, 10, 10),
[PWM_CPT_INT_EN] = REG_FIELD(STI_INT_EN, 1, 4), [PWM_CPT_INT_EN] = REG_FIELD(STI_INT_EN, 1, 4),
[PWM_CPT_INT_STAT] = REG_FIELD(STI_INT_STA, 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) 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; struct sti_pwm_compat_data *cdata = pc->cdata;
unsigned long clk_rate; unsigned long clk_rate;
unsigned long val; unsigned long value;
unsigned int ps; unsigned int ps;
clk_rate = clk_get_rate(pc->pwm_clk); 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; value = NSEC_PER_SEC / clk_rate;
val *= cdata->max_pwm_cnt + 1; value *= cdata->max_pwm_cnt + 1;
if (period % val) { if (period % value)
return -EINVAL; return -EINVAL;
} else {
ps = period / val - 1; ps = period / value - 1;
if (ps > cdata->max_prescale) if (ps > cdata->max_prescale)
return -EINVAL; return -EINVAL;
}
*prescale = ps; *prescale = ps;
return 0; return 0;
} }
/* /*
* For STiH4xx PWM IP, the PWM period is fixed to 256 local clock cycles. * For STiH4xx PWM IP, the PWM period is fixed to 256 local clock cycles. The
* The only way to change the period (apart from changing the PWM input clock) * only way to change the period (apart from changing the PWM input clock) is
* is to change the PWM clock prescaler. * 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 prescaler is of 8 bits, so 256 prescaler values and hence 256 possible
* The requested period will be applied only if it matches one of these * period values are supported (for a particular clock rate). The requested
* 256 values. * 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, 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_chip *pc = to_sti_pwmchip(chip);
struct sti_pwm_compat_data *cdata = pc->cdata; struct sti_pwm_compat_data *cdata = pc->cdata;
unsigned int ncfg, value, prescale = 0;
struct pwm_device *cur = pc->cur; struct pwm_device *cur = pc->cur;
struct device *dev = pc->dev; struct device *dev = pc->dev;
unsigned int prescale = 0, pwmvalx;
int ret;
unsigned int ncfg;
bool period_same = false; bool period_same = false;
int ret;
ncfg = hweight_long(pc->configured); ncfg = hweight_long(pc->configured);
if (ncfg) if (ncfg)
period_same = (period_ns == pwm_get_period(cur)); 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. * 1. No devices have been configured.
* 2. Only one device has been configured and the new request * 2. Only one device has been configured and the new request is for
* is for the same device. * the same device.
* 3. Only one device has been configured and the new request is * 3. Only one device has been configured and the new request is for
* for a new device and period of the new device is same as * a new device and period of the new device is same as the current
* the current configured period. * configured period.
* 4. More than one devices are configured and period of the new * 4. More than one devices are configured and period of the new
* requestis the same as the current period. * 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) if (ret)
goto clk_dis; goto clk_dis;
ret = value = prescale & PWM_PRESCALE_LOW_MASK;
regmap_field_write(pc->prescale_low,
prescale & PWM_PRESCALE_LOW_MASK); ret = regmap_field_write(pc->prescale_low, value);
if (ret) if (ret)
goto clk_dis; goto clk_dis;
ret = value = (prescale & PWM_PRESCALE_HIGH_MASK) >> 4;
regmap_field_write(pc->prescale_high,
(prescale & PWM_PRESCALE_HIGH_MASK) >> 4); ret = regmap_field_write(pc->prescale_high, value);
if (ret) if (ret)
goto clk_dis; 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, * PWM pulse = (max_pwm_count + 1) local cycles,
* that is continuous pulse: signal never goes low. * 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, ret = regmap_write(pc->regmap, PWM_OUT_VAL(pwm->hwpwm), value);
PWM_OUT_VAL(pwm->hwpwm), pwmvalx);
if (ret) if (ret)
goto clk_dis; 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); set_bit(pwm->hwpwm, &pc->configured);
pc->cur = pwm; pc->cur = pwm;
dev_dbg(dev, "prescale:%u, period:%i, duty:%i, pwmvalx:%u\n", dev_dbg(dev, "prescale:%u, period:%i, duty:%i, value:%u\n",
prescale, period_ns, duty_ns, pwmvalx); prescale, period_ns, duty_ns, value);
} else { } else {
return -EINVAL; return -EINVAL;
} }
@ -256,10 +258,11 @@ static int sti_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
int ret = 0; int ret = 0;
/* /*
* Since we have a common enable for all PWM devices, * Since we have a common enable for all PWM devices, do not enable if
* do not enable if already enabled. * already enabled.
*/ */
mutex_lock(&pc->sti_pwm_lock); mutex_lock(&pc->sti_pwm_lock);
if (!pc->en_count) { if (!pc->en_count) {
ret = clk_enable(pc->pwm_clk); ret = clk_enable(pc->pwm_clk);
if (ret) 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); ret = regmap_field_write(pc->pwm_out_en, 1);
if (ret) { if (ret) {
dev_err(dev, "failed to enable PWM device:%d\n", dev_err(dev, "failed to enable PWM device %u: %d\n",
pwm->hwpwm); pwm->hwpwm, ret);
goto out; goto out;
} }
} }
pc->en_count++; pc->en_count++;
out: out:
mutex_unlock(&pc->sti_pwm_lock); mutex_unlock(&pc->sti_pwm_lock);
return ret; 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); struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
mutex_lock(&pc->sti_pwm_lock); mutex_lock(&pc->sti_pwm_lock);
if (--pc->en_count) { if (--pc->en_count) {
mutex_unlock(&pc->sti_pwm_lock); mutex_unlock(&pc->sti_pwm_lock);
return; return;
} }
regmap_field_write(pc->pwm_out_en, 0); regmap_field_write(pc->pwm_out_en, 0);
clk_disable(pc->pwm_clk); clk_disable(pc->pwm_clk);
clk_disable(pc->cpt_clk); clk_disable(pc->cpt_clk);
mutex_unlock(&pc->sti_pwm_lock); mutex_unlock(&pc->sti_pwm_lock);
} }
@ -422,14 +430,13 @@ static irqreturn_t sti_pwm_interrupt(int irq, void *data)
* __| |_________________| |________ * __| |_________________| |________
* ^0 ^1 ^2 * ^0 ^1 ^2
* *
* Capture start by the first available rising edge * Capture start by the first available rising edge. When a
* When a capture event occurs, capture value (CPT_VALx) * capture event occurs, capture value (CPT_VALx) is stored,
* is stored, index incremented, capture edge changed. * 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
* *
* 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, regmap_read(pc->regmap,
@ -445,12 +452,14 @@ static irqreturn_t sti_pwm_interrupt(int irq, void *data)
ddata->index++; ddata->index++;
break; break;
case 2: case 2:
regmap_write(pc->regmap, regmap_write(pc->regmap,
PWM_CPT_EDGE(devicenum), PWM_CPT_EDGE(devicenum),
CPT_EDGE_DISABLED); CPT_EDGE_DISABLED);
wake_up(&ddata->wait); wake_up(&ddata->wait);
break; break;
default: default:
dev_err(dev, "Internal error\n"); 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); return PTR_ERR(pc->pwm_cpt_en);
pc->pwm_cpt_int_en = devm_regmap_field_alloc(dev, pc->regmap, 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)) if (IS_ERR(pc->pwm_cpt_int_en))
return PTR_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 * Setup PWM data with default values: some values could be replaced
* with specific ones provided from Device Tree. * 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_prescale = 0xff;
cdata->max_pwm_cnt = 255; cdata->max_pwm_cnt = 255;
cdata->pwm_num_devs = 0; cdata->pwm_num_devs = 0;
cdata->cpt_num_devs = 0; cdata->cpt_num_devs = 0;