u-boot/drivers/pwm/pwm-ti-ehrpwm.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* EHRPWM PWM driver
*
* Copyright (C) 2020 Dario Binacchi <dariobin@libero.it>
*
* Based on Linux kernel drivers/pwm/pwm-tiehrpwm.c
*/
#include <common.h>
#include <clk.h>
#include <div64.h>
#include <dm.h>
#include <dm/device_compat.h>
#include <pwm.h>
#include <asm/io.h>
#define NSEC_PER_SEC 1000000000L
/* Time base module registers */
#define TI_EHRPWM_TBCTL 0x00
#define TI_EHRPWM_TBPRD 0x0A
#define TI_EHRPWM_TBCTL_PRDLD_MASK BIT(3)
#define TI_EHRPWM_TBCTL_PRDLD_SHDW 0
#define TI_EHRPWM_TBCTL_PRDLD_IMDT BIT(3)
#define TI_EHRPWM_TBCTL_CLKDIV_MASK GENMASK(12, 7)
#define TI_EHRPWM_TBCTL_CTRMODE_MASK GENMASK(1, 0)
#define TI_EHRPWM_TBCTL_CTRMODE_UP 0
#define TI_EHRPWM_TBCTL_CTRMODE_DOWN BIT(0)
#define TI_EHRPWM_TBCTL_CTRMODE_UPDOWN BIT(1)
#define TI_EHRPWM_TBCTL_CTRMODE_FREEZE GENMASK(1, 0)
#define TI_EHRPWM_TBCTL_HSPCLKDIV_SHIFT 7
#define TI_EHRPWM_TBCTL_CLKDIV_SHIFT 10
#define TI_EHRPWM_CLKDIV_MAX 7
#define TI_EHRPWM_HSPCLKDIV_MAX 7
#define TI_EHRPWM_PERIOD_MAX 0xFFFF
/* Counter compare module registers */
#define TI_EHRPWM_CMPA 0x12
#define TI_EHRPWM_CMPB 0x14
/* Action qualifier module registers */
#define TI_EHRPWM_AQCTLA 0x16
#define TI_EHRPWM_AQCTLB 0x18
#define TI_EHRPWM_AQSFRC 0x1A
#define TI_EHRPWM_AQCSFRC 0x1C
#define TI_EHRPWM_AQCTL_CBU_MASK GENMASK(9, 8)
#define TI_EHRPWM_AQCTL_CBU_FRCLOW BIT(8)
#define TI_EHRPWM_AQCTL_CBU_FRCHIGH BIT(9)
#define TI_EHRPWM_AQCTL_CBU_FRCTOGGLE GENMASK(9, 8)
#define TI_EHRPWM_AQCTL_CAU_MASK GENMASK(5, 4)
#define TI_EHRPWM_AQCTL_CAU_FRCLOW BIT(4)
#define TI_EHRPWM_AQCTL_CAU_FRCHIGH BIT(5)
#define TI_EHRPWM_AQCTL_CAU_FRCTOGGLE GENMASK(5, 4)
#define TI_EHRPWM_AQCTL_PRD_MASK GENMASK(3, 2)
#define TI_EHRPWM_AQCTL_PRD_FRCLOW BIT(2)
#define TI_EHRPWM_AQCTL_PRD_FRCHIGH BIT(3)
#define TI_EHRPWM_AQCTL_PRD_FRCTOGGLE GENMASK(3, 2)
#define TI_EHRPWM_AQCTL_ZRO_MASK GENMASK(1, 0)
#define TI_EHRPWM_AQCTL_ZRO_FRCLOW BIT(0)
#define TI_EHRPWM_AQCTL_ZRO_FRCHIGH BIT(1)
#define TI_EHRPWM_AQCTL_ZRO_FRCTOGGLE GENMASK(1, 0)
#define TI_EHRPWM_AQCTL_CHANA_POLNORMAL (TI_EHRPWM_AQCTL_CAU_FRCLOW | \
TI_EHRPWM_AQCTL_PRD_FRCHIGH | \
TI_EHRPWM_AQCTL_ZRO_FRCHIGH)
#define TI_EHRPWM_AQCTL_CHANA_POLINVERSED (TI_EHRPWM_AQCTL_CAU_FRCHIGH | \
TI_EHRPWM_AQCTL_PRD_FRCLOW | \
TI_EHRPWM_AQCTL_ZRO_FRCLOW)
#define TI_EHRPWM_AQCTL_CHANB_POLNORMAL (TI_EHRPWM_AQCTL_CBU_FRCLOW | \
TI_EHRPWM_AQCTL_PRD_FRCHIGH | \
TI_EHRPWM_AQCTL_ZRO_FRCHIGH)
#define TI_EHRPWM_AQCTL_CHANB_POLINVERSED (TI_EHRPWM_AQCTL_CBU_FRCHIGH | \
TI_EHRPWM_AQCTL_PRD_FRCLOW | \
TI_EHRPWM_AQCTL_ZRO_FRCLOW)
#define TI_EHRPWM_AQSFRC_RLDCSF_MASK GENMASK(7, 6)
#define TI_EHRPWM_AQSFRC_RLDCSF_ZRO 0
#define TI_EHRPWM_AQSFRC_RLDCSF_PRD BIT(6)
#define TI_EHRPWM_AQSFRC_RLDCSF_ZROPRD BIT(7)
#define TI_EHRPWM_AQSFRC_RLDCSF_IMDT GENMASK(7, 6)
#define TI_EHRPWM_AQCSFRC_CSFB_MASK GENMASK(3, 2)
#define TI_EHRPWM_AQCSFRC_CSFB_FRCDIS 0
#define TI_EHRPWM_AQCSFRC_CSFB_FRCLOW BIT(2)
#define TI_EHRPWM_AQCSFRC_CSFB_FRCHIGH BIT(3)
#define TI_EHRPWM_AQCSFRC_CSFB_DISSWFRC GENMASK(3, 2)
#define TI_EHRPWM_AQCSFRC_CSFA_MASK GENMASK(1, 0)
#define TI_EHRPWM_AQCSFRC_CSFA_FRCDIS 0
#define TI_EHRPWM_AQCSFRC_CSFA_FRCLOW BIT(0)
#define TI_EHRPWM_AQCSFRC_CSFA_FRCHIGH BIT(1)
#define TI_EHRPWM_AQCSFRC_CSFA_DISSWFRC GENMASK(1, 0)
#define TI_EHRPWM_NUM_CHANNELS 2
struct ti_ehrpwm_priv {
fdt_addr_t regs;
u32 clk_rate;
struct clk tbclk;
unsigned long period_cycles[TI_EHRPWM_NUM_CHANNELS];
bool polarity_reversed[TI_EHRPWM_NUM_CHANNELS];
};
static void ti_ehrpwm_modify(u16 val, u16 mask, fdt_addr_t reg)
{
unsigned short v;
v = readw(reg);
v &= ~mask;
v |= val & mask;
writew(v, reg);
}
static int ti_ehrpwm_set_invert(struct udevice *dev, uint channel,
bool polarity)
{
struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
if (channel >= TI_EHRPWM_NUM_CHANNELS)
return -ENOSPC;
/* Configuration of polarity in hardware delayed, do at enable */
priv->polarity_reversed[channel] = polarity;
return 0;
}
/**
* set_prescale_div - Set up the prescaler divider function
* @rqst_prescaler: prescaler value min
* @prescale_div: prescaler value set
* @tb_clk_div: Time Base Control prescaler bits
*/
static int set_prescale_div(unsigned long rqst_prescaler, u16 *prescale_div,
u16 *tb_clk_div)
{
unsigned int clkdiv, hspclkdiv;
for (clkdiv = 0; clkdiv <= TI_EHRPWM_CLKDIV_MAX; clkdiv++) {
for (hspclkdiv = 0; hspclkdiv <= TI_EHRPWM_HSPCLKDIV_MAX;
hspclkdiv++) {
/*
* calculations for prescaler value :
* prescale_div = HSPCLKDIVIDER * CLKDIVIDER.
* HSPCLKDIVIDER = 2 ** hspclkdiv
* CLKDIVIDER = (1), if clkdiv == 0 *OR*
* (2 * clkdiv), if clkdiv != 0
*
* Configure prescale_div value such that period
* register value is less than 65535.
*/
*prescale_div = (1 << clkdiv) *
(hspclkdiv ? (hspclkdiv * 2) : 1);
if (*prescale_div > rqst_prescaler) {
*tb_clk_div =
(clkdiv << TI_EHRPWM_TBCTL_CLKDIV_SHIFT) |
(hspclkdiv <<
TI_EHRPWM_TBCTL_HSPCLKDIV_SHIFT);
return 0;
}
}
}
return 1;
}
static void ti_ehrpwm_configure_polarity(struct udevice *dev, uint channel)
{
struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
u16 aqctl_val, aqctl_mask;
unsigned int aqctl_reg;
/*
* Configure PWM output to HIGH/LOW level on counter
* reaches compare register value and LOW/HIGH level
* on counter value reaches period register value and
* zero value on counter
*/
if (channel == 1) {
aqctl_reg = TI_EHRPWM_AQCTLB;
aqctl_mask = TI_EHRPWM_AQCTL_CBU_MASK;
if (priv->polarity_reversed[channel])
aqctl_val = TI_EHRPWM_AQCTL_CHANB_POLINVERSED;
else
aqctl_val = TI_EHRPWM_AQCTL_CHANB_POLNORMAL;
} else {
aqctl_reg = TI_EHRPWM_AQCTLA;
aqctl_mask = TI_EHRPWM_AQCTL_CAU_MASK;
if (priv->polarity_reversed[channel])
aqctl_val = TI_EHRPWM_AQCTL_CHANA_POLINVERSED;
else
aqctl_val = TI_EHRPWM_AQCTL_CHANA_POLNORMAL;
}
aqctl_mask |= TI_EHRPWM_AQCTL_PRD_MASK | TI_EHRPWM_AQCTL_ZRO_MASK;
ti_ehrpwm_modify(aqctl_val, aqctl_mask, priv->regs + aqctl_reg);
}
/*
* period_ns = 10^9 * (ps_divval * period_cycles) / PWM_CLK_RATE
* duty_ns = 10^9 * (ps_divval * duty_cycles) / PWM_CLK_RATE
*/
static int ti_ehrpwm_set_config(struct udevice *dev, uint channel,
uint period_ns, uint duty_ns)
{
struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
u32 period_cycles, duty_cycles;
u16 ps_divval, tb_divval;
unsigned int i, cmp_reg;
unsigned long long c;
if (channel >= TI_EHRPWM_NUM_CHANNELS)
return -ENOSPC;
if (period_ns > NSEC_PER_SEC)
return -ERANGE;
c = priv->clk_rate;
c = c * period_ns;
do_div(c, NSEC_PER_SEC);
period_cycles = (unsigned long)c;
if (period_cycles < 1) {
period_cycles = 1;
duty_cycles = 1;
} else {
c = priv->clk_rate;
c = c * duty_ns;
do_div(c, NSEC_PER_SEC);
duty_cycles = (unsigned long)c;
}
dev_dbg(dev, "channel=%d, period_ns=%d, duty_ns=%d\n",
channel, period_ns, duty_ns);
/*
* Period values should be same for multiple PWM channels as IP uses
* same period register for multiple channels.
*/
for (i = 0; i < TI_EHRPWM_NUM_CHANNELS; i++) {
if (priv->period_cycles[i] &&
priv->period_cycles[i] != period_cycles) {
/*
* Allow channel to reconfigure period if no other
* channels being configured.
*/
if (i == channel)
continue;
dev_err(dev, "period value conflicts with channel %u\n",
i);
return -EINVAL;
}
}
priv->period_cycles[channel] = period_cycles;
/* Configure clock prescaler to support Low frequency PWM wave */
if (set_prescale_div(period_cycles / TI_EHRPWM_PERIOD_MAX, &ps_divval,
&tb_divval)) {
dev_err(dev, "unsupported values\n");
return -EINVAL;
}
/* Update clock prescaler values */
ti_ehrpwm_modify(tb_divval, TI_EHRPWM_TBCTL_CLKDIV_MASK,
priv->regs + TI_EHRPWM_TBCTL);
/* Update period & duty cycle with presacler division */
period_cycles = period_cycles / ps_divval;
duty_cycles = duty_cycles / ps_divval;
/* Configure shadow loading on Period register */
ti_ehrpwm_modify(TI_EHRPWM_TBCTL_PRDLD_SHDW, TI_EHRPWM_TBCTL_PRDLD_MASK,
priv->regs + TI_EHRPWM_TBCTL);
writew(period_cycles, priv->regs + TI_EHRPWM_TBPRD);
/* Configure ehrpwm counter for up-count mode */
ti_ehrpwm_modify(TI_EHRPWM_TBCTL_CTRMODE_UP,
TI_EHRPWM_TBCTL_CTRMODE_MASK,
priv->regs + TI_EHRPWM_TBCTL);
if (channel == 1)
/* Channel 1 configured with compare B register */
cmp_reg = TI_EHRPWM_CMPB;
else
/* Channel 0 configured with compare A register */
cmp_reg = TI_EHRPWM_CMPA;
writew(duty_cycles, priv->regs + cmp_reg);
return 0;
}
static int ti_ehrpwm_disable(struct udevice *dev, uint channel)
{
struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
u16 aqcsfrc_val, aqcsfrc_mask;
int err;
if (channel >= TI_EHRPWM_NUM_CHANNELS)
return -ENOSPC;
/* Action Qualifier puts PWM output low forcefully */
if (channel) {
aqcsfrc_val = TI_EHRPWM_AQCSFRC_CSFB_FRCLOW;
aqcsfrc_mask = TI_EHRPWM_AQCSFRC_CSFB_MASK;
} else {
aqcsfrc_val = TI_EHRPWM_AQCSFRC_CSFA_FRCLOW;
aqcsfrc_mask = TI_EHRPWM_AQCSFRC_CSFA_MASK;
}
/* Update shadow register first before modifying active register */
ti_ehrpwm_modify(TI_EHRPWM_AQSFRC_RLDCSF_ZRO,
TI_EHRPWM_AQSFRC_RLDCSF_MASK,
priv->regs + TI_EHRPWM_AQSFRC);
ti_ehrpwm_modify(aqcsfrc_val, aqcsfrc_mask,
priv->regs + TI_EHRPWM_AQCSFRC);
/*
* Changes to immediate action on Action Qualifier. This puts
* Action Qualifier control on PWM output from next TBCLK
*/
ti_ehrpwm_modify(TI_EHRPWM_AQSFRC_RLDCSF_IMDT,
TI_EHRPWM_AQSFRC_RLDCSF_MASK,
priv->regs + TI_EHRPWM_AQSFRC);
ti_ehrpwm_modify(aqcsfrc_val, aqcsfrc_mask,
priv->regs + TI_EHRPWM_AQCSFRC);
/* Disabling TBCLK on PWM disable */
err = clk_disable(&priv->tbclk);
if (err) {
dev_err(dev, "failed to disable tbclk\n");
return err;
}
return 0;
}
static int ti_ehrpwm_enable(struct udevice *dev, uint channel)
{
struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
u16 aqcsfrc_val, aqcsfrc_mask;
int err;
if (channel >= TI_EHRPWM_NUM_CHANNELS)
return -ENOSPC;
/* Disabling Action Qualifier on PWM output */
if (channel) {
aqcsfrc_val = TI_EHRPWM_AQCSFRC_CSFB_FRCDIS;
aqcsfrc_mask = TI_EHRPWM_AQCSFRC_CSFB_MASK;
} else {
aqcsfrc_val = TI_EHRPWM_AQCSFRC_CSFA_FRCDIS;
aqcsfrc_mask = TI_EHRPWM_AQCSFRC_CSFA_MASK;
}
/* Changes to shadow mode */
ti_ehrpwm_modify(TI_EHRPWM_AQSFRC_RLDCSF_ZRO,
TI_EHRPWM_AQSFRC_RLDCSF_MASK,
priv->regs + TI_EHRPWM_AQSFRC);
ti_ehrpwm_modify(aqcsfrc_val, aqcsfrc_mask,
priv->regs + TI_EHRPWM_AQCSFRC);
/* Channels polarity can be configured from action qualifier module */
ti_ehrpwm_configure_polarity(dev, channel);
err = clk_enable(&priv->tbclk);
if (err) {
dev_err(dev, "failed to enable tbclk\n");
return err;
}
return 0;
}
static int ti_ehrpwm_set_enable(struct udevice *dev, uint channel, bool enable)
{
if (enable)
return ti_ehrpwm_enable(dev, channel);
return ti_ehrpwm_disable(dev, channel);
}
static int ti_ehrpwm_of_to_plat(struct udevice *dev)
{
struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
priv->regs = dev_read_addr(dev);
if (priv->regs == FDT_ADDR_T_NONE) {
dev_err(dev, "invalid address\n");
return -EINVAL;
}
dev_dbg(dev, "regs=0x%08lx\n", priv->regs);
return 0;
}
static int ti_ehrpwm_remove(struct udevice *dev)
{
struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
clk_release_all(&priv->tbclk, 1);
return 0;
}
static int ti_ehrpwm_probe(struct udevice *dev)
{
struct ti_ehrpwm_priv *priv = dev_get_priv(dev);
struct clk clk;
int err;
err = clk_get_by_name(dev, "fck", &clk);
if (err) {
dev_err(dev, "failed to get clock\n");
return err;
}
priv->clk_rate = clk_get_rate(&clk);
if (IS_ERR_VALUE(priv->clk_rate) || !priv->clk_rate) {
dev_err(dev, "failed to get clock rate\n");
if (IS_ERR_VALUE(priv->clk_rate))
return priv->clk_rate;
return -EINVAL;
}
/* Acquire tbclk for Time Base EHRPWM submodule */
err = clk_get_by_name(dev, "tbclk", &priv->tbclk);
if (err) {
dev_err(dev, "failed to get tbclk clock\n");
return err;
}
return 0;
}
static const struct pwm_ops ti_ehrpwm_ops = {
.set_config = ti_ehrpwm_set_config,
.set_enable = ti_ehrpwm_set_enable,
.set_invert = ti_ehrpwm_set_invert,
};
static const struct udevice_id ti_ehrpwm_ids[] = {
{.compatible = "ti,am3352-ehrpwm"},
{.compatible = "ti,am33xx-ehrpwm"},
{}
};
U_BOOT_DRIVER(ti_ehrpwm) = {
.name = "ti_ehrpwm",
.id = UCLASS_PWM,
.of_match = ti_ehrpwm_ids,
.ops = &ti_ehrpwm_ops,
.ofdata_to_platdata = ti_ehrpwm_of_to_plat,
.probe = ti_ehrpwm_probe,
.remove = ti_ehrpwm_remove,
.priv_auto = sizeof(struct ti_ehrpwm_priv),
};