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linux/drivers/pwm/pwm-intel-lgm.c

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// 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 regmap *regmap;
u32 period;
};
static inline struct lgm_pwm_chip *to_lgm_pwm_chip(struct pwm_chip *chip)
{
return pwmchip_get_drvdata(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);
}
pwm: Make .get_state() callback return an error code .get_state() might fail in some cases. To make it possible that a driver signals such a failure change the prototype of .get_state() to return an error code. This patch was created using coccinelle and the following semantic patch: @p1@ identifier getstatefunc; identifier driver; @@ struct pwm_ops driver = { ..., .get_state = getstatefunc ,... }; @p2@ identifier p1.getstatefunc; identifier chip, pwm, state; @@ -void +int getstatefunc(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state) { ... - return; + return 0; ... } plus the actual change of the prototype in include/linux/pwm.h (plus some manual fixing of indentions and empty lines). So for now all drivers return success unconditionally. They are adapted in the following patches to make the changes easier reviewable. Reviewed-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> Reviewed-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> Reviewed-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com> Acked-by: Douglas Anderson <dianders@chromium.org> Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com> Acked-by: Pavel Machek <pavel@ucw.cz> Acked-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20221130152148.2769768-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-12-02 11:35:26 -07:00
static int 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);
pwm: Make .get_state() callback return an error code .get_state() might fail in some cases. To make it possible that a driver signals such a failure change the prototype of .get_state() to return an error code. This patch was created using coccinelle and the following semantic patch: @p1@ identifier getstatefunc; identifier driver; @@ struct pwm_ops driver = { ..., .get_state = getstatefunc ,... }; @p2@ identifier p1.getstatefunc; identifier chip, pwm, state; @@ -void +int getstatefunc(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state) { ... - return; + return 0; ... } plus the actual change of the prototype in include/linux/pwm.h (plus some manual fixing of indentions and empty lines). So for now all drivers return success unconditionally. They are adapted in the following patches to make the changes easier reviewable. Reviewed-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> Reviewed-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> Reviewed-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com> Acked-by: Douglas Anderson <dianders@chromium.org> Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com> Acked-by: Pavel Machek <pavel@ucw.cz> Acked-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20221130152148.2769768-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-12-02 11:35:26 -07:00
return 0;
}
static const struct pwm_ops lgm_pwm_ops = {
.get_state = lgm_pwm_get_state,
.apply = lgm_pwm_apply,
};
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 pwm_chip *chip;
struct lgm_pwm_chip *pc;
void __iomem *io_base;
struct clk *clk;
int ret;
chip = devm_pwmchip_alloc(dev, 1, sizeof(*pc));
if (IS_ERR(chip))
return PTR_ERR(chip);
pc = to_lgm_pwm_chip(chip);
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");
chip->ops = &lgm_pwm_ops;
lgm_pwm_init(pc);
ret = devm_pwmchip_add(dev, 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_DESCRIPTION("Intel LGM Pulse Width Modulator driver");
MODULE_LICENSE("GPL v2");