diff options
Diffstat (limited to 'drivers/pwm/pwm-tiehrpwm.c')
| -rw-r--r-- | drivers/pwm/pwm-tiehrpwm.c | 613 |
1 files changed, 613 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-tiehrpwm.c b/drivers/pwm/pwm-tiehrpwm.c new file mode 100644 index 000000000..694b3cf76 --- /dev/null +++ b/drivers/pwm/pwm-tiehrpwm.c @@ -0,0 +1,613 @@ +/* + * 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> + +#include "pwm-tipwmss.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 (test_bit(PWMF_ENABLED, &pwm->flags)) { + 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,am33xx-ehrpwm" }, + {}, +}; +MODULE_DEVICE_TABLE(of, ehrpwm_of_match); + +static int ehrpwm_pwm_probe(struct platform_device *pdev) +{ + int ret; + struct resource *r; + struct clk *clk; + struct ehrpwm_pwm_chip *pc; + u16 status; + + pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL); + if (!pc) + return -ENOMEM; + + clk = devm_clk_get(&pdev->dev, "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); + pm_runtime_get_sync(&pdev->dev); + + status = pwmss_submodule_state_change(pdev->dev.parent, + PWMSS_EPWMCLK_EN); + if (!(status & PWMSS_EPWMCLK_EN_ACK)) { + dev_err(&pdev->dev, "PWMSS config space clock enable failed\n"); + ret = -EINVAL; + goto pwmss_clk_failure; + } + + pm_runtime_put_sync(&pdev->dev); + + platform_set_drvdata(pdev, pc); + return 0; + +pwmss_clk_failure: + pm_runtime_put_sync(&pdev->dev); + pm_runtime_disable(&pdev->dev); + pwmchip_remove(&pc->chip); + clk_unprepare(pc->tbclk); + return ret; +} + +static int ehrpwm_pwm_remove(struct platform_device *pdev) +{ + struct ehrpwm_pwm_chip *pc = platform_get_drvdata(pdev); + + clk_unprepare(pc->tbclk); + + pm_runtime_get_sync(&pdev->dev); + /* + * Due to hardware misbehaviour, acknowledge of the stop_req + * is missing. Hence checking of the status bit skipped. + */ + pwmss_submodule_state_change(pdev->dev.parent, PWMSS_EPWMCLK_STOP_REQ); + pm_runtime_put_sync(&pdev->dev); + + 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 (!test_bit(PWMF_ENABLED, &pwm->flags)) + 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 (!test_bit(PWMF_ENABLED, &pwm->flags)) + 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"); |