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Commit 7d8a600c authored by Lee Jones's avatar Lee Jones Committed by Thierry Reding
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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: default avatarLee Jones <lee.jones@linaro.org>
[thierry.reding@gmail.com: applied some bikeshedding>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent 85a834c4

drivers/pwm/pwm-sti.c

+81 −72
Original line number Diff line number Diff line 
/*

 * 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
@@ -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,
@@ -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;



	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)

{

	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");

		}
@@ -575,7 +584,7 @@ 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->pwm_num_devs = 0;