Contributors: 16
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Sascha Hauer |
598 |
43.43% |
7 |
22.58% |
| Lukasz Majewski |
401 |
29.12% |
7 |
22.58% |
| Philipp Zabel |
184 |
13.36% |
2 |
6.45% |
| Liu Ying |
109 |
7.92% |
2 |
6.45% |
| Holger Schurig |
28 |
2.03% |
1 |
3.23% |
| Axel Lin |
16 |
1.16% |
1 |
3.23% |
| Jason Chen |
12 |
0.87% |
1 |
3.23% |
| Thierry Reding |
10 |
0.73% |
1 |
3.23% |
| Fabio Estevam |
8 |
0.58% |
2 |
6.45% |
| Tejun Heo |
3 |
0.22% |
1 |
3.23% |
| Sachin Kamat |
3 |
0.22% |
1 |
3.23% |
| Richard Zhao |
1 |
0.07% |
1 |
3.23% |
| Bhumika Goyal |
1 |
0.07% |
1 |
3.23% |
| Boris Brezillon |
1 |
0.07% |
1 |
3.23% |
| H Hartley Sweeten |
1 |
0.07% |
1 |
3.23% |
| Lothar Waßmann |
1 |
0.07% |
1 |
3.23% |
| Total |
1377 |
|
31 |
|
// SPDX-License-Identifier: GPL-2.0
/*
* simple driver for PWM (Pulse Width Modulator) controller
*
* Derived from pxa PWM driver by eric miao <eric.miao@marvell.com>
*/
#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/delay.h>
#include <linux/io.h>
#include <linux/pwm.h>
#include <linux/of.h>
#include <linux/of_device.h>
/* i.MX1 and i.MX21 share the same PWM function block: */
#define MX1_PWMC 0x00 /* PWM Control Register */
#define MX1_PWMS 0x04 /* PWM Sample Register */
#define MX1_PWMP 0x08 /* PWM Period Register */
#define MX1_PWMC_EN (1 << 4)
/* i.MX27, i.MX31, i.MX35 share the same PWM function block: */
#define MX3_PWMCR 0x00 /* PWM Control Register */
#define MX3_PWMSR 0x04 /* PWM Status Register */
#define MX3_PWMSAR 0x0C /* PWM Sample Register */
#define MX3_PWMPR 0x10 /* PWM Period Register */
#define MX3_PWMCR_PRESCALER(x) ((((x) - 1) & 0xFFF) << 4)
#define MX3_PWMCR_STOPEN (1 << 25)
#define MX3_PWMCR_DOZEEN (1 << 24)
#define MX3_PWMCR_WAITEN (1 << 23)
#define MX3_PWMCR_DBGEN (1 << 22)
#define MX3_PWMCR_POUTC (1 << 18)
#define MX3_PWMCR_CLKSRC_IPG_HIGH (2 << 16)
#define MX3_PWMCR_CLKSRC_IPG (1 << 16)
#define MX3_PWMCR_SWR (1 << 3)
#define MX3_PWMCR_EN (1 << 0)
#define MX3_PWMSR_FIFOAV_4WORDS 0x4
#define MX3_PWMSR_FIFOAV_MASK 0x7
#define MX3_PWM_SWR_LOOP 5
struct imx_chip {
struct clk *clk_per;
void __iomem *mmio_base;
struct pwm_chip chip;
};
#define to_imx_chip(chip) container_of(chip, struct imx_chip, chip)
static int imx_pwm_config_v1(struct pwm_chip *chip,
struct pwm_device *pwm, int duty_ns, int period_ns)
{
struct imx_chip *imx = to_imx_chip(chip);
/*
* The PWM subsystem allows for exact frequencies. However,
* I cannot connect a scope on my device to the PWM line and
* thus cannot provide the program the PWM controller
* exactly. Instead, I'm relying on the fact that the
* Bootloader (u-boot or WinCE+haret) has programmed the PWM
* function group already. So I'll just modify the PWM sample
* register to follow the ratio of duty_ns vs. period_ns
* accordingly.
*
* This is good enough for programming the brightness of
* the LCD backlight.
*
* The real implementation would divide PERCLK[0] first by
* both the prescaler (/1 .. /128) and then by CLKSEL
* (/2 .. /16).
*/
u32 max = readl(imx->mmio_base + MX1_PWMP);
u32 p = max * duty_ns / period_ns;
writel(max - p, imx->mmio_base + MX1_PWMS);
return 0;
}
static int imx_pwm_enable_v1(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct imx_chip *imx = to_imx_chip(chip);
u32 val;
int ret;
ret = clk_prepare_enable(imx->clk_per);
if (ret < 0)
return ret;
val = readl(imx->mmio_base + MX1_PWMC);
val |= MX1_PWMC_EN;
writel(val, imx->mmio_base + MX1_PWMC);
return 0;
}
static void imx_pwm_disable_v1(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct imx_chip *imx = to_imx_chip(chip);
u32 val;
val = readl(imx->mmio_base + MX1_PWMC);
val &= ~MX1_PWMC_EN;
writel(val, imx->mmio_base + MX1_PWMC);
clk_disable_unprepare(imx->clk_per);
}
static void imx_pwm_sw_reset(struct pwm_chip *chip)
{
struct imx_chip *imx = to_imx_chip(chip);
struct device *dev = chip->dev;
int wait_count = 0;
u32 cr;
writel(MX3_PWMCR_SWR, imx->mmio_base + MX3_PWMCR);
do {
usleep_range(200, 1000);
cr = readl(imx->mmio_base + MX3_PWMCR);
} while ((cr & MX3_PWMCR_SWR) &&
(wait_count++ < MX3_PWM_SWR_LOOP));
if (cr & MX3_PWMCR_SWR)
dev_warn(dev, "software reset timeout\n");
}
static void imx_pwm_wait_fifo_slot(struct pwm_chip *chip,
struct pwm_device *pwm)
{
struct imx_chip *imx = to_imx_chip(chip);
struct device *dev = chip->dev;
unsigned int period_ms;
int fifoav;
u32 sr;
sr = readl(imx->mmio_base + MX3_PWMSR);
fifoav = sr & MX3_PWMSR_FIFOAV_MASK;
if (fifoav == MX3_PWMSR_FIFOAV_4WORDS) {
period_ms = DIV_ROUND_UP(pwm_get_period(pwm),
NSEC_PER_MSEC);
msleep(period_ms);
sr = readl(imx->mmio_base + MX3_PWMSR);
if (fifoav == (sr & MX3_PWMSR_FIFOAV_MASK))
dev_warn(dev, "there is no free FIFO slot\n");
}
}
static int imx_pwm_apply_v2(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
unsigned long period_cycles, duty_cycles, prescale;
struct imx_chip *imx = to_imx_chip(chip);
struct pwm_state cstate;
unsigned long long c;
int ret;
u32 cr;
pwm_get_state(pwm, &cstate);
if (state->enabled) {
c = clk_get_rate(imx->clk_per);
c *= state->period;
do_div(c, 1000000000);
period_cycles = c;
prescale = period_cycles / 0x10000 + 1;
period_cycles /= prescale;
c = (unsigned long long)period_cycles * state->duty_cycle;
do_div(c, state->period);
duty_cycles = c;
/*
* according to imx pwm RM, the real period value should be
* PERIOD value in PWMPR plus 2.
*/
if (period_cycles > 2)
period_cycles -= 2;
else
period_cycles = 0;
/*
* Wait for a free FIFO slot if the PWM is already enabled, and
* flush the FIFO if the PWM was disabled and is about to be
* enabled.
*/
if (cstate.enabled) {
imx_pwm_wait_fifo_slot(chip, pwm);
} else {
ret = clk_prepare_enable(imx->clk_per);
if (ret)
return ret;
imx_pwm_sw_reset(chip);
}
writel(duty_cycles, imx->mmio_base + MX3_PWMSAR);
writel(period_cycles, imx->mmio_base + MX3_PWMPR);
cr = MX3_PWMCR_PRESCALER(prescale) |
MX3_PWMCR_STOPEN | MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN |
MX3_PWMCR_DBGEN | MX3_PWMCR_CLKSRC_IPG_HIGH |
MX3_PWMCR_EN;
if (state->polarity == PWM_POLARITY_INVERSED)
cr |= MX3_PWMCR_POUTC;
writel(cr, imx->mmio_base + MX3_PWMCR);
} else if (cstate.enabled) {
writel(0, imx->mmio_base + MX3_PWMCR);
clk_disable_unprepare(imx->clk_per);
}
return 0;
}
static const struct pwm_ops imx_pwm_ops_v1 = {
.enable = imx_pwm_enable_v1,
.disable = imx_pwm_disable_v1,
.config = imx_pwm_config_v1,
.owner = THIS_MODULE,
};
static const struct pwm_ops imx_pwm_ops_v2 = {
.apply = imx_pwm_apply_v2,
.owner = THIS_MODULE,
};
struct imx_pwm_data {
bool polarity_supported;
const struct pwm_ops *ops;
};
static struct imx_pwm_data imx_pwm_data_v1 = {
.ops = &imx_pwm_ops_v1,
};
static struct imx_pwm_data imx_pwm_data_v2 = {
.polarity_supported = true,
.ops = &imx_pwm_ops_v2,
};
static const struct of_device_id imx_pwm_dt_ids[] = {
{ .compatible = "fsl,imx1-pwm", .data = &imx_pwm_data_v1, },
{ .compatible = "fsl,imx27-pwm", .data = &imx_pwm_data_v2, },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, imx_pwm_dt_ids);
static int imx_pwm_probe(struct platform_device *pdev)
{
const struct of_device_id *of_id =
of_match_device(imx_pwm_dt_ids, &pdev->dev);
const struct imx_pwm_data *data;
struct imx_chip *imx;
struct resource *r;
int ret = 0;
if (!of_id)
return -ENODEV;
data = of_id->data;
imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL);
if (imx == NULL)
return -ENOMEM;
imx->clk_per = devm_clk_get(&pdev->dev, "per");
if (IS_ERR(imx->clk_per)) {
dev_err(&pdev->dev, "getting per clock failed with %ld\n",
PTR_ERR(imx->clk_per));
return PTR_ERR(imx->clk_per);
}
imx->chip.ops = data->ops;
imx->chip.dev = &pdev->dev;
imx->chip.base = -1;
imx->chip.npwm = 1;
if (data->polarity_supported) {
dev_dbg(&pdev->dev, "PWM supports output inversion\n");
imx->chip.of_xlate = of_pwm_xlate_with_flags;
imx->chip.of_pwm_n_cells = 3;
}
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
imx->mmio_base = devm_ioremap_resource(&pdev->dev, r);
if (IS_ERR(imx->mmio_base))
return PTR_ERR(imx->mmio_base);
ret = pwmchip_add(&imx->chip);
if (ret < 0)
return ret;
platform_set_drvdata(pdev, imx);
return 0;
}
static int imx_pwm_remove(struct platform_device *pdev)
{
struct imx_chip *imx;
imx = platform_get_drvdata(pdev);
if (imx == NULL)
return -ENODEV;
return pwmchip_remove(&imx->chip);
}
static struct platform_driver imx_pwm_driver = {
.driver = {
.name = "imx-pwm",
.of_match_table = imx_pwm_dt_ids,
},
.probe = imx_pwm_probe,
.remove = imx_pwm_remove,
};
module_platform_driver(imx_pwm_driver);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");