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// SPDX-License-Identifier: GPL-2.0-only
/*
* drivers/pwm/pwm-pxa.c
*
* simple driver for PWM (Pulse Width Modulator) controller
*
* 2008-02-13 initial version
* eric miao <eric.miao@marvell.com>
*
* Links to reference manuals for some of the supported PWM chips can be found
* in Documentation/arch/arm/marvell.rst.
*
* Limitations:
* - When PWM is stopped, the current PWM period stops abruptly at the next
* input clock (PWMCR_SD is set) and the output is driven to inactive.
*/
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/pwm.h>
#include <linux/of_device.h>
#include <asm/div64.h>
#define HAS_SECONDARY_PWM 0x10
static const struct platform_device_id pwm_id_table[] = {
/* PWM has_secondary_pwm? */
{ "pxa25x-pwm", 0 },
{ "pxa27x-pwm", HAS_SECONDARY_PWM },
{ "pxa168-pwm", 0 },
{ "pxa910-pwm", 0 },
{ },
};
MODULE_DEVICE_TABLE(platform, pwm_id_table);
/* PWM registers and bits definitions */
#define PWMCR (0x00)
#define PWMDCR (0x04)
#define PWMPCR (0x08)
#define PWMCR_SD (1 << 6)
#define PWMDCR_FD (1 << 10)
struct pxa_pwm_chip {
struct pwm_chip chip;
struct device *dev;
struct clk *clk;
void __iomem *mmio_base;
};
static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip)
{
return container_of(chip, struct pxa_pwm_chip, chip);
}
/*
* period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
* duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
*/
static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
u64 duty_ns, u64 period_ns)
{
struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
unsigned long long c;
unsigned long period_cycles, prescale, pv, dc;
unsigned long offset;
offset = pwm->hwpwm ? 0x10 : 0;
c = clk_get_rate(pc->clk);
c = c * period_ns;
do_div(c, 1000000000);
period_cycles = c;
if (period_cycles < 1)
period_cycles = 1;
prescale = (period_cycles - 1) / 1024;
pv = period_cycles / (prescale + 1) - 1;
if (prescale > 63)
return -EINVAL;
if (duty_ns == period_ns)
dc = PWMDCR_FD;
else
dc = mul_u64_u64_div_u64(pv + 1, duty_ns, period_ns);
writel(prescale | PWMCR_SD, pc->mmio_base + offset + PWMCR);
writel(dc, pc->mmio_base + offset + PWMDCR);
writel(pv, pc->mmio_base + offset + PWMPCR);
return 0;
}
static int pxa_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
u64 duty_cycle;
int err;
if (state->polarity != PWM_POLARITY_NORMAL)
return -EINVAL;
err = clk_prepare_enable(pc->clk);
if (err)
return err;
duty_cycle = state->enabled ? state->duty_cycle : 0;
err = pxa_pwm_config(chip, pwm, duty_cycle, state->period);
if (err) {
clk_disable_unprepare(pc->clk);
return err;
}
if (state->enabled && !pwm->state.enabled)
return 0;
clk_disable_unprepare(pc->clk);
if (!state->enabled && pwm->state.enabled)
clk_disable_unprepare(pc->clk);
return 0;
}
static const struct pwm_ops pxa_pwm_ops = {
.apply = pxa_pwm_apply,
};
#ifdef CONFIG_OF
/*
* Device tree users must create one device instance for each PWM channel.
* Hence we dispense with the HAS_SECONDARY_PWM and "tell" the original driver
* code that this is a single channel pxa25x-pwm. Currently all devices are
* supported identically.
*/
static const struct of_device_id pwm_of_match[] = {
{ .compatible = "marvell,pxa250-pwm", .data = &pwm_id_table[0]},
{ .compatible = "marvell,pxa270-pwm", .data = &pwm_id_table[0]},
{ .compatible = "marvell,pxa168-pwm", .data = &pwm_id_table[0]},
{ .compatible = "marvell,pxa910-pwm", .data = &pwm_id_table[0]},
{ }
};
MODULE_DEVICE_TABLE(of, pwm_of_match);
#else
#define pwm_of_match NULL
#endif
static int pwm_probe(struct platform_device *pdev)
{
const struct platform_device_id *id = platform_get_device_id(pdev);
struct pxa_pwm_chip *pc;
int ret = 0;
if (IS_ENABLED(CONFIG_OF) && id == NULL)
id = of_device_get_match_data(&pdev->dev);
if (id == NULL)
return -EINVAL;
pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
if (pc == NULL)
return -ENOMEM;
pc->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(pc->clk))
return PTR_ERR(pc->clk);
pc->chip.dev = &pdev->dev;
pc->chip.ops = &pxa_pwm_ops;
pc->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1;
if (IS_ENABLED(CONFIG_OF)) {
pc->chip.of_xlate = of_pwm_single_xlate;
pc->chip.of_pwm_n_cells = 1;
}
pc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(pc->mmio_base))
return PTR_ERR(pc->mmio_base);
ret = devm_pwmchip_add(&pdev->dev, &pc->chip);
if (ret < 0) {
dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
return ret;
}
return 0;
}
static struct platform_driver pwm_driver = {
.driver = {
.name = "pxa25x-pwm",
.of_match_table = pwm_of_match,
},
.probe = pwm_probe,
.id_table = pwm_id_table,
};
module_platform_driver(pwm_driver);
MODULE_LICENSE("GPL v2");
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