forked from mirrors/linux
pwm: sti: Add new driver for ST's PWM IP
This driver supports all current STi platforms' PWM IPs. Signed-off-by: Ajit Pal Singh <ajitpal.singh@st.com> Signed-off-by: Lee Jones <lee.jones@linaro.org> [thierry.reding: rename module to pwm-sti, fix build breakage] Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Lee Jones
Thierry Reding
parent
31c4fa3442
commit
378fe115d1
3 changed files with 377 additions and 0 deletions
|
|
@ -233,6 +233,16 @@ config PWM_SPEAR
|
|||
To compile this driver as a module, choose M here: the module
|
||||
will be called pwm-spear.
|
||||
|
||||
config PWM_STI
|
||||
tristate "STiH4xx PWM support"
|
||||
depends on ARCH_STI
|
||||
depends on OF
|
||||
help
|
||||
Generic PWM framework driver for STiH4xx SoCs.
|
||||
|
||||
To compile this driver as a module, choose M here: the module
|
||||
will be called pwm-sti.
|
||||
|
||||
config PWM_TEGRA
|
||||
tristate "NVIDIA Tegra PWM support"
|
||||
depends on ARCH_TEGRA
|
||||
|
|
|
|||
|
|
@ -21,6 +21,7 @@ obj-$(CONFIG_PWM_RENESAS_TPU) += pwm-renesas-tpu.o
|
|||
obj-$(CONFIG_PWM_ROCKCHIP) += pwm-rockchip.o
|
||||
obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
|
||||
obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o
|
||||
obj-$(CONFIG_PWM_STI) += pwm-sti.o
|
||||
obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o
|
||||
obj-$(CONFIG_PWM_TIECAP) += pwm-tiecap.o
|
||||
obj-$(CONFIG_PWM_TIEHRPWM) += pwm-tiehrpwm.o
|
||||
|
|
|
|||
366
drivers/pwm/pwm-sti.c
Normal file
366
drivers/pwm/pwm-sti.c
Normal file
|
|
@ -0,0 +1,366 @@
|
|||
/*
|
||||
* PWM device driver for ST SoCs.
|
||||
* Author: Ajit Pal Singh <ajitpal.singh@st.com>
|
||||
*
|
||||
* Copyright (C) 2013-2014 STMicroelectronics (R&D) Limited
|
||||
*
|
||||
* 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; either version 2 of the License, or
|
||||
* (at your option) any later version.
|
||||
*/
|
||||
|
||||
#include <linux/bsearch.h>
|
||||
#include <linux/clk.h>
|
||||
#include <linux/math64.h>
|
||||
#include <linux/mfd/syscon.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/of.h>
|
||||
#include <linux/platform_device.h>
|
||||
#include <linux/pwm.h>
|
||||
#include <linux/regmap.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/time.h>
|
||||
|
||||
#define STI_DS_REG(ch) (4 * (ch)) /* Channel's Duty Cycle register */
|
||||
#define STI_PWMCR 0x50 /* Control/Config register */
|
||||
#define STI_INTEN 0x54 /* Interrupt Enable/Disable register */
|
||||
|
||||
/* Regfield IDs */
|
||||
enum {
|
||||
PWMCLK_PRESCALE,
|
||||
PWM_EN,
|
||||
PWM_INT_EN,
|
||||
|
||||
/* Keep last */
|
||||
MAX_REGFIELDS
|
||||
};
|
||||
|
||||
struct sti_pwm_compat_data {
|
||||
const struct reg_field *reg_fields;
|
||||
unsigned int num_chan;
|
||||
unsigned int max_pwm_cnt;
|
||||
unsigned int max_prescale;
|
||||
};
|
||||
|
||||
struct sti_pwm_chip {
|
||||
struct device *dev;
|
||||
struct clk *clk;
|
||||
unsigned long clk_rate;
|
||||
struct regmap *regmap;
|
||||
struct sti_pwm_compat_data *cdata;
|
||||
struct regmap_field *prescale;
|
||||
struct regmap_field *pwm_en;
|
||||
struct regmap_field *pwm_int_en;
|
||||
unsigned long *pwm_periods;
|
||||
struct pwm_chip chip;
|
||||
void __iomem *mmio;
|
||||
};
|
||||
|
||||
static const struct reg_field sti_pwm_regfields[MAX_REGFIELDS] = {
|
||||
[PWMCLK_PRESCALE] = REG_FIELD(STI_PWMCR, 0, 3),
|
||||
[PWM_EN] = REG_FIELD(STI_PWMCR, 9, 9),
|
||||
[PWM_INT_EN] = REG_FIELD(STI_INTEN, 0, 0),
|
||||
};
|
||||
|
||||
static inline struct sti_pwm_chip *to_sti_pwmchip(struct pwm_chip *chip)
|
||||
{
|
||||
return container_of(chip, struct sti_pwm_chip, chip);
|
||||
}
|
||||
|
||||
/*
|
||||
* Calculate the period values supported by the PWM for the
|
||||
* current clock rate.
|
||||
*/
|
||||
static void sti_pwm_calc_periods(struct sti_pwm_chip *pc)
|
||||
{
|
||||
struct sti_pwm_compat_data *cdata = pc->cdata;
|
||||
struct device *dev = pc->dev;
|
||||
unsigned long val;
|
||||
int i;
|
||||
|
||||
/*
|
||||
* period_ns = (10^9 * (prescaler + 1) * (MAX_PWM_COUNT + 1)) / CLK_RATE
|
||||
*/
|
||||
val = NSEC_PER_SEC / pc->clk_rate;
|
||||
val *= cdata->max_pwm_cnt + 1;
|
||||
|
||||
dev_dbg(dev, "possible periods for clkrate[HZ]:%lu\n", pc->clk_rate);
|
||||
|
||||
for (i = 0; i <= cdata->max_prescale; i++) {
|
||||
pc->pwm_periods[i] = val * (i + 1);
|
||||
dev_dbg(dev, "prescale:%d, period[ns]:%lu\n",
|
||||
i, pc->pwm_periods[i]);
|
||||
}
|
||||
}
|
||||
|
||||
static int sti_pwm_cmp_periods(const void *key, const void *elt)
|
||||
{
|
||||
unsigned long i = *(unsigned long *)key;
|
||||
unsigned long j = *(unsigned long *)elt;
|
||||
|
||||
if (i < j)
|
||||
return -1;
|
||||
else
|
||||
return i == j ? 0 : 1;
|
||||
}
|
||||
|
||||
/*
|
||||
* 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 4 bits, so only 16 prescaler values and hence only
|
||||
* 16 possible period values are supported (for a particular clock rate).
|
||||
* The requested period will be applied only if it matches one of these
|
||||
* 16 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;
|
||||
struct device *dev = pc->dev;
|
||||
unsigned int prescale, pwmvalx;
|
||||
unsigned long *found;
|
||||
int ret;
|
||||
|
||||
/*
|
||||
* Search for matching period value. The corresponding index is our
|
||||
* prescale value
|
||||
*/
|
||||
found = bsearch(&period_ns, &pc->pwm_periods[0],
|
||||
cdata->max_prescale + 1, sizeof(unsigned long),
|
||||
sti_pwm_cmp_periods);
|
||||
if (!found) {
|
||||
dev_err(dev, "failed to find matching period\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
prescale = found - &pc->pwm_periods[0];
|
||||
|
||||
/*
|
||||
* When PWMVal == 0, PWM pulse = 1 local clock cycle.
|
||||
* When PWMVal == max_pwm_count,
|
||||
* 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;
|
||||
|
||||
dev_dbg(dev, "prescale:%u, period:%i, duty:%i, pwmvalx:%u\n",
|
||||
prescale, period_ns, duty_ns, pwmvalx);
|
||||
|
||||
/* Enable clock before writing to PWM registers */
|
||||
ret = clk_enable(pc->clk);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
ret = regmap_field_write(pc->prescale, prescale);
|
||||
if (ret)
|
||||
goto clk_dis;
|
||||
|
||||
ret = regmap_write(pc->regmap, STI_PWMVAL(pwm->hwpwm), pwmvalx);
|
||||
if (ret)
|
||||
goto clk_dis;
|
||||
|
||||
ret = regmap_field_write(pc->pwm_int_en, 0);
|
||||
|
||||
clk_dis:
|
||||
clk_disable(pc->clk);
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int sti_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
|
||||
{
|
||||
struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
|
||||
struct device *dev = pc->dev;
|
||||
int ret;
|
||||
|
||||
ret = clk_enable(pc->clk);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
ret = regmap_field_write(pc->pwm_en, 1);
|
||||
if (ret)
|
||||
dev_err(dev, "%s,pwm_en write failed\n", __func__);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void sti_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
|
||||
{
|
||||
struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
|
||||
struct device *dev = pc->dev;
|
||||
unsigned int val;
|
||||
|
||||
regmap_field_write(pc->pwm_en, 0);
|
||||
|
||||
regmap_read(pc->regmap, STI_CNT, &val);
|
||||
|
||||
dev_dbg(dev, "pwm counter :%u\n", val);
|
||||
|
||||
clk_disable(pc->clk);
|
||||
}
|
||||
|
||||
static const struct pwm_ops sti_pwm_ops = {
|
||||
.config = sti_pwm_config,
|
||||
.enable = sti_pwm_enable,
|
||||
.disable = sti_pwm_disable,
|
||||
.owner = THIS_MODULE,
|
||||
};
|
||||
|
||||
static int sti_pwm_probe_dt(struct sti_pwm_chip *pc)
|
||||
{
|
||||
struct device *dev = pc->dev;
|
||||
const struct reg_field *reg_fields;
|
||||
struct device_node *np = dev->of_node;
|
||||
struct sti_pwm_compat_data *cdata = pc->cdata;
|
||||
u32 num_chan;
|
||||
|
||||
of_property_read_u32(np, "st,pwm-num-chan", &num_chan);
|
||||
if (num_chan)
|
||||
cdata->num_chan = num_chan;
|
||||
|
||||
reg_fields = cdata->reg_fields;
|
||||
|
||||
pc->prescale = devm_regmap_field_alloc(dev, pc->regmap,
|
||||
reg_fields[PWMCLK_PRESCALE]);
|
||||
if (IS_ERR(pc->prescale))
|
||||
return PTR_ERR(pc->prescale);
|
||||
|
||||
pc->pwm_en = devm_regmap_field_alloc(dev, pc->regmap,
|
||||
reg_fields[PWM_EN]);
|
||||
if (IS_ERR(pc->pwm_en))
|
||||
return PTR_ERR(pc->pwm_en);
|
||||
|
||||
pc->pwm_int_en = devm_regmap_field_alloc(dev, pc->regmap,
|
||||
reg_fields[PWM_INT_EN]);
|
||||
if (IS_ERR(pc->pwm_int_en))
|
||||
return PTR_ERR(pc->pwm_int_en);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct regmap_config sti_pwm_regmap_config = {
|
||||
.reg_bits = 32,
|
||||
.val_bits = 32,
|
||||
.reg_stride = 4,
|
||||
};
|
||||
|
||||
static int sti_pwm_probe(struct platform_device *pdev)
|
||||
{
|
||||
struct device *dev = &pdev->dev;
|
||||
struct sti_pwm_compat_data *cdata;
|
||||
struct sti_pwm_chip *pc;
|
||||
struct resource *res;
|
||||
int ret;
|
||||
|
||||
pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL);
|
||||
if (!pc)
|
||||
return -ENOMEM;
|
||||
|
||||
cdata = devm_kzalloc(dev, sizeof(*cdata), GFP_KERNEL);
|
||||
if (!cdata)
|
||||
return -ENOMEM;
|
||||
|
||||
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||||
|
||||
pc->mmio = devm_ioremap_resource(dev, res);
|
||||
if (IS_ERR(pc->mmio))
|
||||
return PTR_ERR(pc->mmio);
|
||||
|
||||
pc->regmap = devm_regmap_init_mmio(dev, pc->mmio,
|
||||
&sti_pwm_regmap_config);
|
||||
if (IS_ERR(pc->regmap))
|
||||
return PTR_ERR(pc->regmap);
|
||||
|
||||
/*
|
||||
* 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->max_prescale = 0xff;
|
||||
cdata->max_pwm_cnt = 255;
|
||||
cdata->num_chan = 1;
|
||||
|
||||
pc->cdata = cdata;
|
||||
pc->dev = dev;
|
||||
|
||||
ret = sti_pwm_probe_dt(pc);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
pc->pwm_periods = devm_kzalloc(dev,
|
||||
sizeof(unsigned long) * (pc->cdata->max_prescale + 1),
|
||||
GFP_KERNEL);
|
||||
if (!pc->pwm_periods)
|
||||
return -ENOMEM;
|
||||
|
||||
pc->clk = of_clk_get_by_name(dev->of_node, "pwm");
|
||||
if (IS_ERR(pc->clk)) {
|
||||
dev_err(dev, "failed to get PWM clock\n");
|
||||
return PTR_ERR(pc->clk);
|
||||
}
|
||||
|
||||
pc->clk_rate = clk_get_rate(pc->clk);
|
||||
if (!pc->clk_rate) {
|
||||
dev_err(dev, "failed to get clock rate\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
ret = clk_prepare(pc->clk);
|
||||
if (ret) {
|
||||
dev_err(dev, "failed to prepare clock\n");
|
||||
return ret;
|
||||
}
|
||||
|
||||
sti_pwm_calc_periods(pc);
|
||||
|
||||
pc->chip.dev = dev;
|
||||
pc->chip.ops = &sti_pwm_ops;
|
||||
pc->chip.base = -1;
|
||||
pc->chip.npwm = pc->cdata->num_chan;
|
||||
pc->chip.can_sleep = true;
|
||||
|
||||
ret = pwmchip_add(&pc->chip);
|
||||
if (ret < 0) {
|
||||
clk_unprepare(pc->clk);
|
||||
return ret;
|
||||
}
|
||||
|
||||
platform_set_drvdata(pdev, pc);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int sti_pwm_remove(struct platform_device *pdev)
|
||||
{
|
||||
struct sti_pwm_chip *pc = platform_get_drvdata(pdev);
|
||||
unsigned int i;
|
||||
|
||||
for (i = 0; i < pc->cdata->num_chan; i++)
|
||||
pwm_disable(&pc->chip.pwms[i]);
|
||||
|
||||
clk_unprepare(pc->clk);
|
||||
|
||||
return pwmchip_remove(&pc->chip);
|
||||
}
|
||||
|
||||
static const struct of_device_id sti_pwm_of_match[] = {
|
||||
{ .compatible = "st,sti-pwm", },
|
||||
{ /* sentinel */ }
|
||||
};
|
||||
MODULE_DEVICE_TABLE(of, sti_pwm_of_match);
|
||||
|
||||
static struct platform_driver sti_pwm_driver = {
|
||||
.driver = {
|
||||
.name = "sti-pwm",
|
||||
.of_match_table = sti_pwm_of_match,
|
||||
},
|
||||
.probe = sti_pwm_probe,
|
||||
.remove = sti_pwm_remove,
|
||||
};
|
||||
module_platform_driver(sti_pwm_driver);
|
||||
|
||||
MODULE_AUTHOR("Ajit Pal Singh <ajitpal.singh@st.com>");
|
||||
MODULE_DESCRIPTION("STMicroelectronics ST PWM driver");
|
||||
MODULE_LICENSE("GPL");
|
||||
Loading…
Reference in a new issue