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Add driver for OpenCores PWM Controller.
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mmoll committed Mar 24, 2024
1 parent 08dcfb3 commit 7dd9b97
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7 changes: 7 additions & 0 deletions MAINTAINERS
Original file line number Diff line number Diff line change
Expand Up @@ -16547,6 +16547,13 @@ F: Documentation/i2c/busses/i2c-ocores.rst
F: drivers/i2c/busses/i2c-ocores.c
F: include/linux/platform_data/i2c-ocores.h

OPENCORES PWM DRIVER
M: William Qiu <[email protected]>
M: Hal Feng <[email protected]>
S: Supported
F: Documentation/devicetree/bindings/pwm/opencores,pwm.yaml
F: drivers/pwm/pwm-ocores.c

OPENRISC ARCHITECTURE
M: Jonas Bonn <[email protected]>
M: Stefan Kristiansson <[email protected]>
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12 changes: 12 additions & 0 deletions drivers/pwm/Kconfig
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Expand Up @@ -444,6 +444,18 @@ config PWM_NTXEC
controller found in certain e-book readers designed by the original
design manufacturer Netronix.

config PWM_OCORES
tristate "OpenCores PWM support"
depends on HAS_IOMEM && OF
depends on COMMON_CLK && RESET_CONTROLLER
depends on ARCH_STARFIVE || COMPILE_TEST
help
If you say yes to this option, support will be included for the
OpenCores PWM. For details see https://opencores.org/projects/ptc.

To compile this driver as a module, choose M here: the module
will be called pwm-ocores.

config PWM_OMAP_DMTIMER
tristate "OMAP Dual-Mode Timer PWM support"
depends on OF
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1 change: 1 addition & 0 deletions drivers/pwm/Makefile
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Expand Up @@ -40,6 +40,7 @@ obj-$(CONFIG_PWM_MICROCHIP_CORE) += pwm-microchip-core.o
obj-$(CONFIG_PWM_MTK_DISP) += pwm-mtk-disp.o
obj-$(CONFIG_PWM_MXS) += pwm-mxs.o
obj-$(CONFIG_PWM_NTXEC) += pwm-ntxec.o
obj-$(CONFIG_PWM_OCORES) += pwm-ocores.o
obj-$(CONFIG_PWM_OMAP_DMTIMER) += pwm-omap-dmtimer.o
obj-$(CONFIG_PWM_PCA9685) += pwm-pca9685.o
obj-$(CONFIG_PWM_PXA) += pwm-pxa.o
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232 changes: 232 additions & 0 deletions drivers/pwm/pwm-ocores.c
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@@ -0,0 +1,232 @@
// SPDX-License-Identifier: GPL-2.0
/*
* OpenCores PWM Driver
*
* https://opencores.org/projects/ptc
*
* Copyright (C) 2018-2023 StarFive Technology Co., Ltd.
*
* Limitations:
* - The hardware only do inverted polarity.
* - The hardware minimum period / duty_cycle is (1 / pwm_apb clock frequency) ns.
* - The hardware maximum period / duty_cycle is (U32_MAX / pwm_apb clock frequency) ns.
*/

#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/reset.h>
#include <linux/slab.h>

/* OCPWM_CTRL register bits*/
#define REG_OCPWM_EN BIT(0)
#define REG_OCPWM_ECLK BIT(1)
#define REG_OCPWM_NEC BIT(2)
#define REG_OCPWM_OE BIT(3)
#define REG_OCPWM_SIGNLE BIT(4)
#define REG_OCPWM_INTE BIT(5)
#define REG_OCPWM_INT BIT(6)
#define REG_OCPWM_CNTRRST BIT(7)
#define REG_OCPWM_CAPTE BIT(8)

struct ocores_pwm_device {
struct pwm_chip chip;
struct clk *clk;
struct reset_control *rst;
const struct ocores_pwm_data *data;
void __iomem *regs;
u32 clk_rate; /* PWM APB clock frequency */
};

struct ocores_pwm_data {
void __iomem *(*get_ch_base)(void __iomem *base, unsigned int channel);
};

static inline u32 ocores_readl(struct ocores_pwm_device *ddata,
unsigned int channel,
unsigned int offset)
{
void __iomem *base = ddata->data->get_ch_base ?
ddata->data->get_ch_base(ddata->regs, channel) : ddata->regs;

return readl(base + offset);
}

static inline void ocores_writel(struct ocores_pwm_device *ddata,
unsigned int channel,
unsigned int offset, u32 val)
{
void __iomem *base = ddata->data->get_ch_base ?
ddata->data->get_ch_base(ddata->regs, channel) : ddata->regs;

writel(val, base + offset);
}

static inline struct ocores_pwm_device *chip_to_ocores(struct pwm_chip *chip)
{
return container_of(chip, struct ocores_pwm_device, chip);
}

static void __iomem *starfive_jh71x0_get_ch_base(void __iomem *base,
unsigned int channel)
{
unsigned int offset = (channel > 3 ? 1 << 15 : 0) + (channel & 3) * 0x10;

return base + offset;
}

static int ocores_pwm_get_state(struct pwm_chip *chip,
struct pwm_device *pwm,
struct pwm_state *state)
{
struct ocores_pwm_device *ddata = chip_to_ocores(chip);
u32 period_data, duty_data, ctrl_data;

period_data = ocores_readl(ddata, pwm->hwpwm, 0x8);
duty_data = ocores_readl(ddata, pwm->hwpwm, 0x4);
ctrl_data = ocores_readl(ddata, pwm->hwpwm, 0xC);

state->period = DIV_ROUND_UP_ULL((u64)period_data * NSEC_PER_SEC, ddata->clk_rate);
state->duty_cycle = DIV_ROUND_UP_ULL((u64)duty_data * NSEC_PER_SEC, ddata->clk_rate);
state->polarity = PWM_POLARITY_INVERSED;
state->enabled = (ctrl_data & REG_OCPWM_EN) ? true : false;

return 0;
}

static int ocores_pwm_apply(struct pwm_chip *chip,
struct pwm_device *pwm,
const struct pwm_state *state)
{
struct ocores_pwm_device *ddata = chip_to_ocores(chip);
u32 ctrl_data = 0;
u64 period_data, duty_data;

if (state->polarity != PWM_POLARITY_INVERSED)
return -EINVAL;

ctrl_data = ocores_readl(ddata, pwm->hwpwm, 0xC);
ocores_writel(ddata, pwm->hwpwm, 0xC, 0);

period_data = DIV_ROUND_DOWN_ULL(state->period * ddata->clk_rate, NSEC_PER_SEC);
if (period_data <= U32_MAX)
ocores_writel(ddata, pwm->hwpwm, 0x8, (u32)period_data);
else
return -EINVAL;

duty_data = DIV_ROUND_DOWN_ULL(state->duty_cycle * ddata->clk_rate, NSEC_PER_SEC);
if (duty_data <= U32_MAX)
ocores_writel(ddata, pwm->hwpwm, 0x4, (u32)duty_data);
else
return -EINVAL;

ocores_writel(ddata, pwm->hwpwm, 0xC, 0);

if (state->enabled) {
ctrl_data = ocores_readl(ddata, pwm->hwpwm, 0xC);
ocores_writel(ddata, pwm->hwpwm, 0xC, ctrl_data | REG_OCPWM_EN | REG_OCPWM_OE);
}

return 0;
}

static const struct pwm_ops ocores_pwm_ops = {
.get_state = ocores_pwm_get_state,
.apply = ocores_pwm_apply,
};

static const struct ocores_pwm_data jh7100_pwm_data = {
.get_ch_base = starfive_jh71x0_get_ch_base,
};

static const struct ocores_pwm_data jh7110_pwm_data = {
.get_ch_base = starfive_jh71x0_get_ch_base,
};

static const struct of_device_id ocores_pwm_of_match[] = {
{ .compatible = "opencores,pwm-v1" },
{ .compatible = "starfive,jh7100-pwm", .data = &jh7100_pwm_data},
{ .compatible = "starfive,jh7110-pwm", .data = &jh7110_pwm_data},
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, ocores_pwm_of_match);

static void ocores_reset_control_assert(void *data)
{
reset_control_assert(data);
}

static int ocores_pwm_probe(struct platform_device *pdev)
{
const struct of_device_id *id;
struct device *dev = &pdev->dev;
struct ocores_pwm_device *ddata;
struct pwm_chip *chip;
int ret;

id = of_match_device(ocores_pwm_of_match, dev);
if (!id)
return -EINVAL;

ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
if (!ddata)
return -ENOMEM;

ddata->data = id->data;
chip = &ddata->chip;
chip->dev = dev;
chip->ops = &ocores_pwm_ops;
chip->npwm = 8;

ddata->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(ddata->regs))
return dev_err_probe(dev, PTR_ERR(ddata->regs),
"Unable to map IO resources\n");

ddata->clk = devm_clk_get_enabled(dev, NULL);
if (IS_ERR(ddata->clk))
return dev_err_probe(dev, PTR_ERR(ddata->clk),
"Unable to get pwm's clock\n");

ddata->rst = devm_reset_control_get_optional_exclusive(dev, NULL);
if (IS_ERR(ddata->rst))
return dev_err_probe(dev, PTR_ERR(ddata->rst),
"Unable to get pwm's reset\n");

reset_control_deassert(ddata->rst);

ret = devm_add_action_or_reset(dev, ocores_reset_control_assert, ddata->rst);
if (ret)
return ret;

ddata->clk_rate = clk_get_rate(ddata->clk);
if (ddata->clk_rate <= 0)
return dev_err_probe(dev, ddata->clk_rate,
"Unable to get clock's rate\n");

ret = devm_pwmchip_add(dev, chip);
if (ret < 0)
return dev_err_probe(dev, ret, "Could not register PWM chip\n");

platform_set_drvdata(pdev, ddata);

return ret;
}

static struct platform_driver ocores_pwm_driver = {
.probe = ocores_pwm_probe,
.driver = {
.name = "ocores-pwm",
.of_match_table = ocores_pwm_of_match,
},
};
module_platform_driver(ocores_pwm_driver);

MODULE_AUTHOR("Jieqin Chen");
MODULE_AUTHOR("Hal Feng <[email protected]>");
MODULE_DESCRIPTION("OpenCores PWM PTC driver");
MODULE_LICENSE("GPL");

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