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pwm: Add support for Broadcom iProc PWM controller

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Add support for the PWM controller present in Broadcom's iProc family of
SoCs. It has been tested on the  Northstar+ bcm958625HR board.

Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
[thierry.reding@gmail.com: bunch of coding style fixes, cleanups]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Yendapally Reddy Dhananjaya Reddy 2016-07-05 02:00:25 -04:00 committed by Thierry Reding
parent f734f6ddbc
commit daa5abc41c
3 changed files with 288 additions and 0 deletions
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10
drivers/pwm/Kconfig
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@ -74,6 +74,16 @@ config PWM_ATMEL_TCB
To compile this driver as a module, choose M here: the module
will be called pwm-atmel-tcb.
config PWM_BCM_IPROC
tristate "iProc PWM support"
depends on ARCH_BCM_IPROC
help
Generic PWM framework driver for Broadcom iProc PWM block. This
block is used in Broadcom iProc SoC's.
To compile this driver as a module, choose M here: the module
will be called pwm-bcm-iproc.
config PWM_BCM_KONA
tristate "Kona PWM support"
depends on ARCH_BCM_MOBILE

1
drivers/pwm/Makefile
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@ -4,6 +4,7 @@ obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o
obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o
obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM) += pwm-atmel-hlcdc.o
obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o
obj-$(CONFIG_PWM_BCM_IPROC) += pwm-bcm-iproc.o
obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o
obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o
obj-$(CONFIG_PWM_BERLIN) += pwm-berlin.o

277
drivers/pwm/pwm-bcm-iproc.c Normal file
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@ -0,0 +1,277 @@
/*
* Copyright (C) 2016 Broadcom
*
* 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 the Free Software Foundation version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#define IPROC_PWM_CTRL_OFFSET 0x00
#define IPROC_PWM_CTRL_TYPE_SHIFT(ch) (15 + (ch))
#define IPROC_PWM_CTRL_POLARITY_SHIFT(ch) (8 + (ch))
#define IPROC_PWM_CTRL_EN_SHIFT(ch) (ch)
#define IPROC_PWM_PERIOD_OFFSET(ch) (0x04 + ((ch) << 3))
#define IPROC_PWM_PERIOD_MIN 0x02
#define IPROC_PWM_PERIOD_MAX 0xffff
#define IPROC_PWM_DUTY_CYCLE_OFFSET(ch) (0x08 + ((ch) << 3))
#define IPROC_PWM_DUTY_CYCLE_MIN 0x00
#define IPROC_PWM_DUTY_CYCLE_MAX 0xffff
#define IPROC_PWM_PRESCALE_OFFSET 0x24
#define IPROC_PWM_PRESCALE_BITS 0x06
#define IPROC_PWM_PRESCALE_SHIFT(ch) ((3 - (ch)) * \
IPROC_PWM_PRESCALE_BITS)
#define IPROC_PWM_PRESCALE_MASK(ch) (IPROC_PWM_PRESCALE_MAX << \
IPROC_PWM_PRESCALE_SHIFT(ch))
#define IPROC_PWM_PRESCALE_MIN 0x00
#define IPROC_PWM_PRESCALE_MAX 0x3f
struct iproc_pwmc {
struct pwm_chip chip;
void __iomem *base;
struct clk *clk;
};
static inline struct iproc_pwmc *to_iproc_pwmc(struct pwm_chip *chip)
{
return container_of(chip, struct iproc_pwmc, chip);
}
static void iproc_pwmc_enable(struct iproc_pwmc *ip, unsigned int channel)
{
u32 value;
value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
value |= 1 << IPROC_PWM_CTRL_EN_SHIFT(channel);
writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
/* must be a 400 ns delay between clearing and setting enable bit */
ndelay(400);
}
static void iproc_pwmc_disable(struct iproc_pwmc *ip, unsigned int channel)
{
u32 value;
value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
value &= ~(1 << IPROC_PWM_CTRL_EN_SHIFT(channel));
writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
/* must be a 400 ns delay between clearing and setting enable bit */
ndelay(400);
}
static void iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct iproc_pwmc *ip = to_iproc_pwmc(chip);
u64 tmp, multi, rate;
u32 value, prescale;
rate = clk_get_rate(ip->clk);
value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
if (value & BIT(IPROC_PWM_CTRL_EN_SHIFT(pwm->hwpwm)))
state->enabled = true;
else
state->enabled = false;
if (value & BIT(IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm)))
state->polarity = PWM_POLARITY_NORMAL;
else
state->polarity = PWM_POLARITY_INVERSED;
value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
prescale = value >> IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);
prescale &= IPROC_PWM_PRESCALE_MAX;
multi = NSEC_PER_SEC * (prescale + 1);
value = readl(ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm));
tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;
state->period = div64_u64(tmp, rate);
value = readl(ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm));
tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;
state->duty_cycle = div64_u64(tmp, rate);
}
static int iproc_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
unsigned long prescale = IPROC_PWM_PRESCALE_MIN;
struct iproc_pwmc *ip = to_iproc_pwmc(chip);
u32 value, period, duty;
u64 rate;
rate = clk_get_rate(ip->clk);
/*
* Find period count, duty count and prescale to suit duty_cycle and
* period. This is done according to formulas described below:
*
* period_ns = 10^9 * (PRESCALE + 1) * PC / PWM_CLK_RATE
* duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
*
* PC = (PWM_CLK_RATE * period_ns) / (10^9 * (PRESCALE + 1))
* DC = (PWM_CLK_RATE * duty_ns) / (10^9 * (PRESCALE + 1))
*/
while (1) {
u64 value, div;
div = NSEC_PER_SEC * (prescale + 1);
value = rate * state->period;
period = div64_u64(value, div);
value = rate * state->duty_cycle;
duty = div64_u64(value, div);
if (period < IPROC_PWM_PERIOD_MIN ||
duty < IPROC_PWM_DUTY_CYCLE_MIN)
return -EINVAL;
if (period <= IPROC_PWM_PERIOD_MAX &&
duty <= IPROC_PWM_DUTY_CYCLE_MAX)
break;
/* Otherwise, increase prescale and recalculate counts */
if (++prescale > IPROC_PWM_PRESCALE_MAX)
return -EINVAL;
}
iproc_pwmc_disable(ip, pwm->hwpwm);
/* Set prescale */
value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
value &= ~IPROC_PWM_PRESCALE_MASK(pwm->hwpwm);
value |= prescale << IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);
writel(value, ip->base + IPROC_PWM_PRESCALE_OFFSET);
/* set period and duty cycle */
writel(period, ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm));
writel(duty, ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm));
/* set polarity */
value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
if (state->polarity == PWM_POLARITY_NORMAL)
value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm);
else
value &= ~(1 << IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm));
writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
if (state->enabled)
iproc_pwmc_enable(ip, pwm->hwpwm);
return 0;
}
static const struct pwm_ops iproc_pwm_ops = {
.apply = iproc_pwmc_apply,
.get_state = iproc_pwmc_get_state,
};
static int iproc_pwmc_probe(struct platform_device *pdev)
{
struct iproc_pwmc *ip;
struct resource *res;
unsigned int i;
u32 value;
int ret;
ip = devm_kzalloc(&pdev->dev, sizeof(*ip), GFP_KERNEL);
if (!ip)
return -ENOMEM;
platform_set_drvdata(pdev, ip);
ip->chip.dev = &pdev->dev;
ip->chip.ops = &iproc_pwm_ops;
ip->chip.base = -1;
ip->chip.npwm = 4;
ip->chip.of_xlate = of_pwm_xlate_with_flags;
ip->chip.of_pwm_n_cells = 3;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
ip->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(ip->base))
return PTR_ERR(ip->base);
ip->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(ip->clk)) {
dev_err(&pdev->dev, "failed to get clock: %ld\n",
PTR_ERR(ip->clk));
return PTR_ERR(ip->clk);
}
ret = clk_prepare_enable(ip->clk);
if (ret < 0) {
dev_err(&pdev->dev, "failed to enable clock: %d\n", ret);
return ret;
}
/* Set full drive and normal polarity for all channels */
value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
for (i = 0; i < ip->chip.npwm; i++) {
value &= ~(1 << IPROC_PWM_CTRL_TYPE_SHIFT(i));
value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(i);
}
writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
ret = pwmchip_add(&ip->chip);
if (ret < 0) {
dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
clk_disable_unprepare(ip->clk);
}
return ret;
}
static int iproc_pwmc_remove(struct platform_device *pdev)
{
struct iproc_pwmc *ip = platform_get_drvdata(pdev);
clk_disable_unprepare(ip->clk);
return pwmchip_remove(&ip->chip);
}
static const struct of_device_id bcm_iproc_pwmc_dt[] = {
{ .compatible = "brcm,iproc-pwm" },
{ },
};
MODULE_DEVICE_TABLE(of, bcm_iproc_pwmc_dt);
static struct platform_driver iproc_pwmc_driver = {
.driver = {
.name = "bcm-iproc-pwm",
.of_match_table = bcm_iproc_pwmc_dt,
},
.probe = iproc_pwmc_probe,
.remove = iproc_pwmc_remove,
};
module_platform_driver(iproc_pwmc_driver);
MODULE_AUTHOR("Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>");
MODULE_DESCRIPTION("Broadcom iProc PWM driver");
MODULE_LICENSE("GPL v2");