linux-stable/drivers/pwm/pwm-tiehrpwm.c
Cooper Jr., Franklin cc37655e6b pwm: pwm-ti*: Remove support for local clock gating
The PWMSS local clock gating registers have no real purpose on OMAP ARM
devices. These registers were left over registers from DSP IP where the
PRCM doesn't exist. There is a silicon bug where gating and ungating clocks
don't function properly. TRMs will be update to indicate that these
registers shouldn't be touched.

Therefore, all code that accesses the PWMSS_CLKCONFIG or PWMSS_CLKSTATUS
will be removed by this patch with zero loss of functionality by the ECAP
and EPWM drivers.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-07-11 12:07:18 +02:00

593 lines
16 KiB
C

/*
* EHRPWM PWM driver
*
* Copyright (C) 2012 Texas Instruments, Inc. - http://www.ti.com/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/pm_runtime.h>
#include <linux/of_device.h>
/* EHRPWM registers and bits definitions */
/* Time base module registers */
#define TBCTL 0x00
#define TBPRD 0x0A
#define TBCTL_RUN_MASK (BIT(15) | BIT(14))
#define TBCTL_STOP_NEXT 0
#define TBCTL_STOP_ON_CYCLE BIT(14)
#define TBCTL_FREE_RUN (BIT(15) | BIT(14))
#define TBCTL_PRDLD_MASK BIT(3)
#define TBCTL_PRDLD_SHDW 0
#define TBCTL_PRDLD_IMDT BIT(3)
#define TBCTL_CLKDIV_MASK (BIT(12) | BIT(11) | BIT(10) | BIT(9) | \
BIT(8) | BIT(7))
#define TBCTL_CTRMODE_MASK (BIT(1) | BIT(0))
#define TBCTL_CTRMODE_UP 0
#define TBCTL_CTRMODE_DOWN BIT(0)
#define TBCTL_CTRMODE_UPDOWN BIT(1)
#define TBCTL_CTRMODE_FREEZE (BIT(1) | BIT(0))
#define TBCTL_HSPCLKDIV_SHIFT 7
#define TBCTL_CLKDIV_SHIFT 10
#define CLKDIV_MAX 7
#define HSPCLKDIV_MAX 7
#define PERIOD_MAX 0xFFFF
/* compare module registers */
#define CMPA 0x12
#define CMPB 0x14
/* Action qualifier module registers */
#define AQCTLA 0x16
#define AQCTLB 0x18
#define AQSFRC 0x1A
#define AQCSFRC 0x1C
#define AQCTL_CBU_MASK (BIT(9) | BIT(8))
#define AQCTL_CBU_FRCLOW BIT(8)
#define AQCTL_CBU_FRCHIGH BIT(9)
#define AQCTL_CBU_FRCTOGGLE (BIT(9) | BIT(8))
#define AQCTL_CAU_MASK (BIT(5) | BIT(4))
#define AQCTL_CAU_FRCLOW BIT(4)
#define AQCTL_CAU_FRCHIGH BIT(5)
#define AQCTL_CAU_FRCTOGGLE (BIT(5) | BIT(4))
#define AQCTL_PRD_MASK (BIT(3) | BIT(2))
#define AQCTL_PRD_FRCLOW BIT(2)
#define AQCTL_PRD_FRCHIGH BIT(3)
#define AQCTL_PRD_FRCTOGGLE (BIT(3) | BIT(2))
#define AQCTL_ZRO_MASK (BIT(1) | BIT(0))
#define AQCTL_ZRO_FRCLOW BIT(0)
#define AQCTL_ZRO_FRCHIGH BIT(1)
#define AQCTL_ZRO_FRCTOGGLE (BIT(1) | BIT(0))
#define AQCTL_CHANA_POLNORMAL (AQCTL_CAU_FRCLOW | AQCTL_PRD_FRCHIGH | \
AQCTL_ZRO_FRCHIGH)
#define AQCTL_CHANA_POLINVERSED (AQCTL_CAU_FRCHIGH | AQCTL_PRD_FRCLOW | \
AQCTL_ZRO_FRCLOW)
#define AQCTL_CHANB_POLNORMAL (AQCTL_CBU_FRCLOW | AQCTL_PRD_FRCHIGH | \
AQCTL_ZRO_FRCHIGH)
#define AQCTL_CHANB_POLINVERSED (AQCTL_CBU_FRCHIGH | AQCTL_PRD_FRCLOW | \
AQCTL_ZRO_FRCLOW)
#define AQSFRC_RLDCSF_MASK (BIT(7) | BIT(6))
#define AQSFRC_RLDCSF_ZRO 0
#define AQSFRC_RLDCSF_PRD BIT(6)
#define AQSFRC_RLDCSF_ZROPRD BIT(7)
#define AQSFRC_RLDCSF_IMDT (BIT(7) | BIT(6))
#define AQCSFRC_CSFB_MASK (BIT(3) | BIT(2))
#define AQCSFRC_CSFB_FRCDIS 0
#define AQCSFRC_CSFB_FRCLOW BIT(2)
#define AQCSFRC_CSFB_FRCHIGH BIT(3)
#define AQCSFRC_CSFB_DISSWFRC (BIT(3) | BIT(2))
#define AQCSFRC_CSFA_MASK (BIT(1) | BIT(0))
#define AQCSFRC_CSFA_FRCDIS 0
#define AQCSFRC_CSFA_FRCLOW BIT(0)
#define AQCSFRC_CSFA_FRCHIGH BIT(1)
#define AQCSFRC_CSFA_DISSWFRC (BIT(1) | BIT(0))
#define NUM_PWM_CHANNEL 2 /* EHRPWM channels */
struct ehrpwm_context {
u16 tbctl;
u16 tbprd;
u16 cmpa;
u16 cmpb;
u16 aqctla;
u16 aqctlb;
u16 aqsfrc;
u16 aqcsfrc;
};
struct ehrpwm_pwm_chip {
struct pwm_chip chip;
unsigned int clk_rate;
void __iomem *mmio_base;
unsigned long period_cycles[NUM_PWM_CHANNEL];
enum pwm_polarity polarity[NUM_PWM_CHANNEL];
struct clk *tbclk;
struct ehrpwm_context ctx;
};
static inline struct ehrpwm_pwm_chip *to_ehrpwm_pwm_chip(struct pwm_chip *chip)
{
return container_of(chip, struct ehrpwm_pwm_chip, chip);
}
static inline u16 ehrpwm_read(void __iomem *base, int offset)
{
return readw(base + offset);
}
static inline void ehrpwm_write(void __iomem *base, int offset, unsigned int val)
{
writew(val & 0xFFFF, base + offset);
}
static void ehrpwm_modify(void __iomem *base, int offset,
unsigned short mask, unsigned short val)
{
unsigned short regval;
regval = readw(base + offset);
regval &= ~mask;
regval |= val & mask;
writew(regval, base + offset);
}
/**
* 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,
unsigned short *prescale_div, unsigned short *tb_clk_div)
{
unsigned int clkdiv, hspclkdiv;
for (clkdiv = 0; clkdiv <= CLKDIV_MAX; clkdiv++) {
for (hspclkdiv = 0; hspclkdiv <= 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 << TBCTL_CLKDIV_SHIFT) |
(hspclkdiv << TBCTL_HSPCLKDIV_SHIFT);
return 0;
}
}
}
return 1;
}
static void configure_polarity(struct ehrpwm_pwm_chip *pc, int chan)
{
int aqctl_reg;
unsigned short aqctl_val, aqctl_mask;
/*
* 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 (chan == 1) {
aqctl_reg = AQCTLB;
aqctl_mask = AQCTL_CBU_MASK;
if (pc->polarity[chan] == PWM_POLARITY_INVERSED)
aqctl_val = AQCTL_CHANB_POLINVERSED;
else
aqctl_val = AQCTL_CHANB_POLNORMAL;
} else {
aqctl_reg = AQCTLA;
aqctl_mask = AQCTL_CAU_MASK;
if (pc->polarity[chan] == PWM_POLARITY_INVERSED)
aqctl_val = AQCTL_CHANA_POLINVERSED;
else
aqctl_val = AQCTL_CHANA_POLNORMAL;
}
aqctl_mask |= AQCTL_PRD_MASK | AQCTL_ZRO_MASK;
ehrpwm_modify(pc->mmio_base, aqctl_reg, aqctl_mask, aqctl_val);
}
/*
* period_ns = 10^9 * (ps_divval * period_cycles) / PWM_CLK_RATE
* duty_ns = 10^9 * (ps_divval * duty_cycles) / PWM_CLK_RATE
*/
static int ehrpwm_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
unsigned long long c;
unsigned long period_cycles, duty_cycles;
unsigned short ps_divval, tb_divval;
int i, cmp_reg;
if (period_ns > NSEC_PER_SEC)
return -ERANGE;
c = pc->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 = pc->clk_rate;
c = c * duty_ns;
do_div(c, NSEC_PER_SEC);
duty_cycles = (unsigned long)c;
}
/*
* Period values should be same for multiple PWM channels as IP uses
* same period register for multiple channels.
*/
for (i = 0; i < NUM_PWM_CHANNEL; i++) {
if (pc->period_cycles[i] &&
(pc->period_cycles[i] != period_cycles)) {
/*
* Allow channel to reconfigure period if no other
* channels being configured.
*/
if (i == pwm->hwpwm)
continue;
dev_err(chip->dev, "Period value conflicts with channel %d\n",
i);
return -EINVAL;
}
}
pc->period_cycles[pwm->hwpwm] = period_cycles;
/* Configure clock prescaler to support Low frequency PWM wave */
if (set_prescale_div(period_cycles/PERIOD_MAX, &ps_divval,
&tb_divval)) {
dev_err(chip->dev, "Unsupported values\n");
return -EINVAL;
}
pm_runtime_get_sync(chip->dev);
/* Update clock prescaler values */
ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CLKDIV_MASK, tb_divval);
/* 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 */
ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_PRDLD_MASK, TBCTL_PRDLD_SHDW);
ehrpwm_write(pc->mmio_base, TBPRD, period_cycles);
/* Configure ehrpwm counter for up-count mode */
ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CTRMODE_MASK,
TBCTL_CTRMODE_UP);
if (pwm->hwpwm == 1)
/* Channel 1 configured with compare B register */
cmp_reg = CMPB;
else
/* Channel 0 configured with compare A register */
cmp_reg = CMPA;
ehrpwm_write(pc->mmio_base, cmp_reg, duty_cycles);
pm_runtime_put_sync(chip->dev);
return 0;
}
static int ehrpwm_pwm_set_polarity(struct pwm_chip *chip,
struct pwm_device *pwm, enum pwm_polarity polarity)
{
struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
/* Configuration of polarity in hardware delayed, do at enable */
pc->polarity[pwm->hwpwm] = polarity;
return 0;
}
static int ehrpwm_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
unsigned short aqcsfrc_val, aqcsfrc_mask;
int ret;
/* Leave clock enabled on enabling PWM */
pm_runtime_get_sync(chip->dev);
/* Disabling Action Qualifier on PWM output */
if (pwm->hwpwm) {
aqcsfrc_val = AQCSFRC_CSFB_FRCDIS;
aqcsfrc_mask = AQCSFRC_CSFB_MASK;
} else {
aqcsfrc_val = AQCSFRC_CSFA_FRCDIS;
aqcsfrc_mask = AQCSFRC_CSFA_MASK;
}
/* Changes to shadow mode */
ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
AQSFRC_RLDCSF_ZRO);
ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);
/* Channels polarity can be configured from action qualifier module */
configure_polarity(pc, pwm->hwpwm);
/* Enable TBCLK before enabling PWM device */
ret = clk_enable(pc->tbclk);
if (ret) {
dev_err(chip->dev, "Failed to enable TBCLK for %s\n",
dev_name(pc->chip.dev));
return ret;
}
/* Enable time counter for free_run */
ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_RUN_MASK, TBCTL_FREE_RUN);
return 0;
}
static void ehrpwm_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
unsigned short aqcsfrc_val, aqcsfrc_mask;
/* Action Qualifier puts PWM output low forcefully */
if (pwm->hwpwm) {
aqcsfrc_val = AQCSFRC_CSFB_FRCLOW;
aqcsfrc_mask = AQCSFRC_CSFB_MASK;
} else {
aqcsfrc_val = AQCSFRC_CSFA_FRCLOW;
aqcsfrc_mask = AQCSFRC_CSFA_MASK;
}
/*
* Changes to immediate action on Action Qualifier. This puts
* Action Qualifier control on PWM output from next TBCLK
*/
ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
AQSFRC_RLDCSF_IMDT);
ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);
/* Disabling TBCLK on PWM disable */
clk_disable(pc->tbclk);
/* Stop Time base counter */
ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_RUN_MASK, TBCTL_STOP_NEXT);
/* Disable clock on PWM disable */
pm_runtime_put_sync(chip->dev);
}
static void ehrpwm_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
if (pwm_is_enabled(pwm)) {
dev_warn(chip->dev, "Removing PWM device without disabling\n");
pm_runtime_put_sync(chip->dev);
}
/* set period value to zero on free */
pc->period_cycles[pwm->hwpwm] = 0;
}
static const struct pwm_ops ehrpwm_pwm_ops = {
.free = ehrpwm_pwm_free,
.config = ehrpwm_pwm_config,
.set_polarity = ehrpwm_pwm_set_polarity,
.enable = ehrpwm_pwm_enable,
.disable = ehrpwm_pwm_disable,
.owner = THIS_MODULE,
};
static const struct of_device_id ehrpwm_of_match[] = {
{ .compatible = "ti,am3352-ehrpwm" },
{ .compatible = "ti,am33xx-ehrpwm" },
{},
};
MODULE_DEVICE_TABLE(of, ehrpwm_of_match);
static int ehrpwm_pwm_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
int ret;
struct resource *r;
struct clk *clk;
struct ehrpwm_pwm_chip *pc;
pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
if (!pc)
return -ENOMEM;
clk = devm_clk_get(&pdev->dev, "fck");
if (IS_ERR(clk)) {
if (of_device_is_compatible(np, "ti,am33xx-ecap")) {
dev_warn(&pdev->dev, "Binding is obsolete.\n");
clk = devm_clk_get(pdev->dev.parent, "fck");
}
}
if (IS_ERR(clk)) {
dev_err(&pdev->dev, "failed to get clock\n");
return PTR_ERR(clk);
}
pc->clk_rate = clk_get_rate(clk);
if (!pc->clk_rate) {
dev_err(&pdev->dev, "failed to get clock rate\n");
return -EINVAL;
}
pc->chip.dev = &pdev->dev;
pc->chip.ops = &ehrpwm_pwm_ops;
pc->chip.of_xlate = of_pwm_xlate_with_flags;
pc->chip.of_pwm_n_cells = 3;
pc->chip.base = -1;
pc->chip.npwm = NUM_PWM_CHANNEL;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
pc->mmio_base = devm_ioremap_resource(&pdev->dev, r);
if (IS_ERR(pc->mmio_base))
return PTR_ERR(pc->mmio_base);
/* Acquire tbclk for Time Base EHRPWM submodule */
pc->tbclk = devm_clk_get(&pdev->dev, "tbclk");
if (IS_ERR(pc->tbclk)) {
dev_err(&pdev->dev, "Failed to get tbclk\n");
return PTR_ERR(pc->tbclk);
}
ret = clk_prepare(pc->tbclk);
if (ret < 0) {
dev_err(&pdev->dev, "clk_prepare() failed: %d\n", ret);
return ret;
}
ret = pwmchip_add(&pc->chip);
if (ret < 0) {
dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
return ret;
}
pm_runtime_enable(&pdev->dev);
platform_set_drvdata(pdev, pc);
return 0;
}
static int ehrpwm_pwm_remove(struct platform_device *pdev)
{
struct ehrpwm_pwm_chip *pc = platform_get_drvdata(pdev);
clk_unprepare(pc->tbclk);
pm_runtime_put_sync(&pdev->dev);
pm_runtime_disable(&pdev->dev);
return pwmchip_remove(&pc->chip);
}
#ifdef CONFIG_PM_SLEEP
static void ehrpwm_pwm_save_context(struct ehrpwm_pwm_chip *pc)
{
pm_runtime_get_sync(pc->chip.dev);
pc->ctx.tbctl = ehrpwm_read(pc->mmio_base, TBCTL);
pc->ctx.tbprd = ehrpwm_read(pc->mmio_base, TBPRD);
pc->ctx.cmpa = ehrpwm_read(pc->mmio_base, CMPA);
pc->ctx.cmpb = ehrpwm_read(pc->mmio_base, CMPB);
pc->ctx.aqctla = ehrpwm_read(pc->mmio_base, AQCTLA);
pc->ctx.aqctlb = ehrpwm_read(pc->mmio_base, AQCTLB);
pc->ctx.aqsfrc = ehrpwm_read(pc->mmio_base, AQSFRC);
pc->ctx.aqcsfrc = ehrpwm_read(pc->mmio_base, AQCSFRC);
pm_runtime_put_sync(pc->chip.dev);
}
static void ehrpwm_pwm_restore_context(struct ehrpwm_pwm_chip *pc)
{
ehrpwm_write(pc->mmio_base, TBPRD, pc->ctx.tbprd);
ehrpwm_write(pc->mmio_base, CMPA, pc->ctx.cmpa);
ehrpwm_write(pc->mmio_base, CMPB, pc->ctx.cmpb);
ehrpwm_write(pc->mmio_base, AQCTLA, pc->ctx.aqctla);
ehrpwm_write(pc->mmio_base, AQCTLB, pc->ctx.aqctlb);
ehrpwm_write(pc->mmio_base, AQSFRC, pc->ctx.aqsfrc);
ehrpwm_write(pc->mmio_base, AQCSFRC, pc->ctx.aqcsfrc);
ehrpwm_write(pc->mmio_base, TBCTL, pc->ctx.tbctl);
}
static int ehrpwm_pwm_suspend(struct device *dev)
{
struct ehrpwm_pwm_chip *pc = dev_get_drvdata(dev);
int i;
ehrpwm_pwm_save_context(pc);
for (i = 0; i < pc->chip.npwm; i++) {
struct pwm_device *pwm = &pc->chip.pwms[i];
if (!pwm_is_enabled(pwm))
continue;
/* Disable explicitly if PWM is running */
pm_runtime_put_sync(dev);
}
return 0;
}
static int ehrpwm_pwm_resume(struct device *dev)
{
struct ehrpwm_pwm_chip *pc = dev_get_drvdata(dev);
int i;
for (i = 0; i < pc->chip.npwm; i++) {
struct pwm_device *pwm = &pc->chip.pwms[i];
if (!pwm_is_enabled(pwm))
continue;
/* Enable explicitly if PWM was running */
pm_runtime_get_sync(dev);
}
ehrpwm_pwm_restore_context(pc);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(ehrpwm_pwm_pm_ops, ehrpwm_pwm_suspend,
ehrpwm_pwm_resume);
static struct platform_driver ehrpwm_pwm_driver = {
.driver = {
.name = "ehrpwm",
.of_match_table = ehrpwm_of_match,
.pm = &ehrpwm_pwm_pm_ops,
},
.probe = ehrpwm_pwm_probe,
.remove = ehrpwm_pwm_remove,
};
module_platform_driver(ehrpwm_pwm_driver);
MODULE_DESCRIPTION("EHRPWM PWM driver");
MODULE_AUTHOR("Texas Instruments");
MODULE_LICENSE("GPL");