blob: b66c350740870e390c6c4e41eeba1b056adc20f8 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2020 Intel Corporation.
*
* Limitations:
* - The hardware supports fixed period & configures only 2-wire mode.
* - Supports normal polarity. Does not support changing polarity.
* - When PWM is disabled, output of PWM will become 0(inactive). It doesn't
* keep track of running period.
* - When duty cycle is changed, PWM output may be a mix of previous setting
* and new setting for the first period. From second period, the output is
* based on new setting.
* - It is a dedicated PWM fan controller. There are no other consumers for
* this PWM controller.
*/
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
#include <linux/pwm.h>
#include <linux/regmap.h>
#include <linux/reset.h>
#define LGM_PWM_FAN_CON0 0x0
#define LGM_PWM_FAN_EN_EN BIT(0)
#define LGM_PWM_FAN_EN_DIS 0x0
#define LGM_PWM_FAN_EN_MSK BIT(0)
#define LGM_PWM_FAN_MODE_2WIRE 0x0
#define LGM_PWM_FAN_MODE_MSK BIT(1)
#define LGM_PWM_FAN_DC_MSK GENMASK(23, 16)
#define LGM_PWM_FAN_CON1 0x4
#define LGM_PWM_FAN_MAX_RPM_MSK GENMASK(15, 0)
#define LGM_PWM_MAX_RPM (BIT(16) - 1)
#define LGM_PWM_DEFAULT_RPM 4000
#define LGM_PWM_MAX_DUTY_CYCLE (BIT(8) - 1)
#define LGM_PWM_DC_BITS 8
#define LGM_PWM_PERIOD_2WIRE_NS (40 * NSEC_PER_MSEC)
struct lgm_pwm_chip {
struct pwm_chip chip;
struct regmap *regmap;
u32 period;
};
static inline struct lgm_pwm_chip *to_lgm_pwm_chip(struct pwm_chip *chip)
{
return container_of(chip, struct lgm_pwm_chip, chip);
}
static int lgm_pwm_enable(struct pwm_chip *chip, bool enable)
{
struct lgm_pwm_chip *pc = to_lgm_pwm_chip(chip);
struct regmap *regmap = pc->regmap;
return regmap_update_bits(regmap, LGM_PWM_FAN_CON0, LGM_PWM_FAN_EN_MSK,
enable ? LGM_PWM_FAN_EN_EN : LGM_PWM_FAN_EN_DIS);
}
static int lgm_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct lgm_pwm_chip *pc = to_lgm_pwm_chip(chip);
u32 duty_cycle, val;
int ret;
/* The hardware only supports normal polarity and fixed period. */
if (state->polarity != PWM_POLARITY_NORMAL || state->period < pc->period)
return -EINVAL;
if (!state->enabled)
return lgm_pwm_enable(chip, 0);
duty_cycle = min_t(u64, state->duty_cycle, pc->period);
val = duty_cycle * LGM_PWM_MAX_DUTY_CYCLE / pc->period;
ret = regmap_update_bits(pc->regmap, LGM_PWM_FAN_CON0, LGM_PWM_FAN_DC_MSK,
FIELD_PREP(LGM_PWM_FAN_DC_MSK, val));
if (ret)
return ret;
return lgm_pwm_enable(chip, 1);
}
static void lgm_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct lgm_pwm_chip *pc = to_lgm_pwm_chip(chip);
u32 duty, val;
state->enabled = regmap_test_bits(pc->regmap, LGM_PWM_FAN_CON0,
LGM_PWM_FAN_EN_EN);
state->polarity = PWM_POLARITY_NORMAL;
state->period = pc->period; /* fixed period */
regmap_read(pc->regmap, LGM_PWM_FAN_CON0, &val);
duty = FIELD_GET(LGM_PWM_FAN_DC_MSK, val);
state->duty_cycle = DIV_ROUND_UP(duty * pc->period, LGM_PWM_MAX_DUTY_CYCLE);
}
static const struct pwm_ops lgm_pwm_ops = {
.get_state = lgm_pwm_get_state,
.apply = lgm_pwm_apply,
.owner = THIS_MODULE,
};
static void lgm_pwm_init(struct lgm_pwm_chip *pc)
{
struct regmap *regmap = pc->regmap;
u32 con0_val;
con0_val = FIELD_PREP(LGM_PWM_FAN_MODE_MSK, LGM_PWM_FAN_MODE_2WIRE);
pc->period = LGM_PWM_PERIOD_2WIRE_NS;
regmap_update_bits(regmap, LGM_PWM_FAN_CON1, LGM_PWM_FAN_MAX_RPM_MSK,
LGM_PWM_DEFAULT_RPM);
regmap_update_bits(regmap, LGM_PWM_FAN_CON0, LGM_PWM_FAN_MODE_MSK,
con0_val);
}
static const struct regmap_config lgm_pwm_regmap_config = {
.reg_bits = 32,
.reg_stride = 4,
.val_bits = 32,
};
static void lgm_clk_release(void *data)
{
struct clk *clk = data;
clk_disable_unprepare(clk);
}
static int lgm_clk_enable(struct device *dev, struct clk *clk)
{
int ret;
ret = clk_prepare_enable(clk);
if (ret)
return ret;
return devm_add_action_or_reset(dev, lgm_clk_release, clk);
}
static void lgm_reset_control_release(void *data)
{
struct reset_control *rst = data;
reset_control_assert(rst);
}
static int lgm_reset_control_deassert(struct device *dev, struct reset_control *rst)
{
int ret;
ret = reset_control_deassert(rst);
if (ret)
return ret;
return devm_add_action_or_reset(dev, lgm_reset_control_release, rst);
}
static int lgm_pwm_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct reset_control *rst;
struct lgm_pwm_chip *pc;
void __iomem *io_base;
struct clk *clk;
int ret;
pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL);
if (!pc)
return -ENOMEM;
io_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(io_base))
return PTR_ERR(io_base);
pc->regmap = devm_regmap_init_mmio(dev, io_base, &lgm_pwm_regmap_config);
if (IS_ERR(pc->regmap))
return dev_err_probe(dev, PTR_ERR(pc->regmap),
"failed to init register map\n");
clk = devm_clk_get(dev, NULL);
if (IS_ERR(clk))
return dev_err_probe(dev, PTR_ERR(clk), "failed to get clock\n");
ret = lgm_clk_enable(dev, clk);
if (ret)
return dev_err_probe(dev, ret, "failed to enable clock\n");
rst = devm_reset_control_get_exclusive(dev, NULL);
if (IS_ERR(rst))
return dev_err_probe(dev, PTR_ERR(rst),
"failed to get reset control\n");
ret = lgm_reset_control_deassert(dev, rst);
if (ret)
return dev_err_probe(dev, ret, "cannot deassert reset control\n");
pc->chip.dev = dev;
pc->chip.ops = &lgm_pwm_ops;
pc->chip.npwm = 1;
lgm_pwm_init(pc);
ret = devm_pwmchip_add(dev, &pc->chip);
if (ret < 0)
return dev_err_probe(dev, ret, "failed to add PWM chip\n");
return 0;
}
static const struct of_device_id lgm_pwm_of_match[] = {
{ .compatible = "intel,lgm-pwm" },
{ }
};
MODULE_DEVICE_TABLE(of, lgm_pwm_of_match);
static struct platform_driver lgm_pwm_driver = {
.driver = {
.name = "intel-pwm",
.of_match_table = lgm_pwm_of_match,
},
.probe = lgm_pwm_probe,
};
module_platform_driver(lgm_pwm_driver);
MODULE_LICENSE("GPL v2");