mirror of https://gitee.com/openkylin/linux.git
pwm: pwm-tiehrpwm: PWM driver support for EHRPWM
Enhanced high resolution PWM module (EHRPWM) hardware can be used to generate PWM output over 2 channels. This commit adds PWM driver support for EHRPWM device present on AM33XX SOC. Current implementation supports simple PWM functionality. Reviewed-by: Vaibhav Bedia <vaibhav.bedia@ti.com> Signed-off-by: Philip, Avinash <avinashphilip@ti.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
This commit is contained in:
Philip, Avinash
Thierry Reding
parent
8e0cb05b3b
commit
19891b20e7
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@ -86,6 +86,16 @@ config PWM_TIECAP
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To compile this driver as a module, choose M here: the module
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will be called pwm-tiecap.
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config PWM_TIEHRPWM
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tristate "EHRPWM PWM support"
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depends on SOC_AM33XX
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help
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PWM driver support for the EHRPWM controller found on AM33XX
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TI SOC
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To compile this driver as a module, choose M here: the module
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will be called pwm-tiehrpwm.
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config PWM_VT8500
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tristate "vt8500 pwm support"
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depends on ARCH_VT8500
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@ -7,4 +7,5 @@ obj-$(CONFIG_PWM_PXA) += pwm-pxa.o
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obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
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obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o
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obj-$(CONFIG_PWM_TIECAP) += pwm-tiecap.o
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obj-$(CONFIG_PWM_TIEHRPWM) += pwm-tiehrpwm.o
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obj-$(CONFIG_PWM_VT8500) += pwm-vt8500.o
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@ -0,0 +1,411 @@
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/*
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* EHRPWM PWM driver
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*
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* Copyright (C) 2012 Texas Instruments, Inc. - http://www.ti.com/
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/pwm.h>
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#include <linux/io.h>
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#include <linux/err.h>
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#include <linux/clk.h>
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#include <linux/pm_runtime.h>
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/* EHRPWM registers and bits definitions */
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/* Time base module registers */
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#define TBCTL 0x00
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#define TBPRD 0x0A
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#define TBCTL_RUN_MASK (BIT(15) | BIT(14))
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#define TBCTL_STOP_NEXT 0
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#define TBCTL_STOP_ON_CYCLE BIT(14)
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#define TBCTL_FREE_RUN (BIT(15) | BIT(14))
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#define TBCTL_PRDLD_MASK BIT(3)
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#define TBCTL_PRDLD_SHDW 0
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#define TBCTL_PRDLD_IMDT BIT(3)
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#define TBCTL_CLKDIV_MASK (BIT(12) | BIT(11) | BIT(10) | BIT(9) | \
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BIT(8) | BIT(7))
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#define TBCTL_CTRMODE_MASK (BIT(1) | BIT(0))
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#define TBCTL_CTRMODE_UP 0
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#define TBCTL_CTRMODE_DOWN BIT(0)
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#define TBCTL_CTRMODE_UPDOWN BIT(1)
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#define TBCTL_CTRMODE_FREEZE (BIT(1) | BIT(0))
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#define TBCTL_HSPCLKDIV_SHIFT 7
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#define TBCTL_CLKDIV_SHIFT 10
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#define CLKDIV_MAX 7
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#define HSPCLKDIV_MAX 7
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#define PERIOD_MAX 0xFFFF
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/* compare module registers */
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#define CMPA 0x12
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#define CMPB 0x14
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/* Action qualifier module registers */
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#define AQCTLA 0x16
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#define AQCTLB 0x18
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#define AQSFRC 0x1A
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#define AQCSFRC 0x1C
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#define AQCTL_CBU_MASK (BIT(9) | BIT(8))
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#define AQCTL_CBU_FRCLOW BIT(8)
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#define AQCTL_CBU_FRCHIGH BIT(9)
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#define AQCTL_CBU_FRCTOGGLE (BIT(9) | BIT(8))
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#define AQCTL_CAU_MASK (BIT(5) | BIT(4))
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#define AQCTL_CAU_FRCLOW BIT(4)
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#define AQCTL_CAU_FRCHIGH BIT(5)
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#define AQCTL_CAU_FRCTOGGLE (BIT(5) | BIT(4))
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#define AQCTL_PRD_MASK (BIT(3) | BIT(2))
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#define AQCTL_PRD_FRCLOW BIT(2)
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#define AQCTL_PRD_FRCHIGH BIT(3)
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#define AQCTL_PRD_FRCTOGGLE (BIT(3) | BIT(2))
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#define AQCTL_ZRO_MASK (BIT(1) | BIT(0))
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#define AQCTL_ZRO_FRCLOW BIT(0)
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#define AQCTL_ZRO_FRCHIGH BIT(1)
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#define AQCTL_ZRO_FRCTOGGLE (BIT(1) | BIT(0))
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#define AQSFRC_RLDCSF_MASK (BIT(7) | BIT(6))
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#define AQSFRC_RLDCSF_ZRO 0
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#define AQSFRC_RLDCSF_PRD BIT(6)
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#define AQSFRC_RLDCSF_ZROPRD BIT(7)
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#define AQSFRC_RLDCSF_IMDT (BIT(7) | BIT(6))
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#define AQCSFRC_CSFB_MASK (BIT(3) | BIT(2))
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#define AQCSFRC_CSFB_FRCDIS 0
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#define AQCSFRC_CSFB_FRCLOW BIT(2)
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#define AQCSFRC_CSFB_FRCHIGH BIT(3)
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#define AQCSFRC_CSFB_DISSWFRC (BIT(3) | BIT(2))
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#define AQCSFRC_CSFA_MASK (BIT(1) | BIT(0))
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#define AQCSFRC_CSFA_FRCDIS 0
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#define AQCSFRC_CSFA_FRCLOW BIT(0)
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#define AQCSFRC_CSFA_FRCHIGH BIT(1)
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#define AQCSFRC_CSFA_DISSWFRC (BIT(1) | BIT(0))
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#define NUM_PWM_CHANNEL 2 /* EHRPWM channels */
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struct ehrpwm_pwm_chip {
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struct pwm_chip chip;
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unsigned int clk_rate;
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void __iomem *mmio_base;
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};
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static inline struct ehrpwm_pwm_chip *to_ehrpwm_pwm_chip(struct pwm_chip *chip)
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{
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return container_of(chip, struct ehrpwm_pwm_chip, chip);
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}
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static void ehrpwm_write(void *base, int offset, unsigned int val)
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{
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writew(val & 0xFFFF, base + offset);
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}
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static void ehrpwm_modify(void *base, int offset,
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unsigned short mask, unsigned short val)
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{
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unsigned short regval;
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regval = readw(base + offset);
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regval &= ~mask;
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regval |= val & mask;
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writew(regval, base + offset);
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}
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/**
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* set_prescale_div - Set up the prescaler divider function
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* @rqst_prescaler: prescaler value min
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* @prescale_div: prescaler value set
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* @tb_clk_div: Time Base Control prescaler bits
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*/
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static int set_prescale_div(unsigned long rqst_prescaler,
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unsigned short *prescale_div, unsigned short *tb_clk_div)
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{
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unsigned int clkdiv, hspclkdiv;
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for (clkdiv = 0; clkdiv <= CLKDIV_MAX; clkdiv++) {
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for (hspclkdiv = 0; hspclkdiv <= HSPCLKDIV_MAX; hspclkdiv++) {
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/*
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* calculations for prescaler value :
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* prescale_div = HSPCLKDIVIDER * CLKDIVIDER.
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* HSPCLKDIVIDER = 2 ** hspclkdiv
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* CLKDIVIDER = (1), if clkdiv == 0 *OR*
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* (2 * clkdiv), if clkdiv != 0
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*
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* Configure prescale_div value such that period
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* register value is less than 65535.
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*/
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*prescale_div = (1 << clkdiv) *
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(hspclkdiv ? (hspclkdiv * 2) : 1);
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if (*prescale_div > rqst_prescaler) {
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*tb_clk_div = (clkdiv << TBCTL_CLKDIV_SHIFT) |
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(hspclkdiv << TBCTL_HSPCLKDIV_SHIFT);
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return 0;
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}
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}
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}
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return 1;
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}
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static void configure_chans(struct ehrpwm_pwm_chip *pc, int chan,
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unsigned long duty_cycles)
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{
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int cmp_reg, aqctl_reg;
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unsigned short aqctl_val, aqctl_mask;
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/*
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* Channels can be configured from action qualifier module.
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* Channel 0 configured with compare A register and for
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* up-counter mode.
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* Channel 1 configured with compare B register and for
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* up-counter mode.
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*/
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if (chan == 1) {
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aqctl_reg = AQCTLB;
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cmp_reg = CMPB;
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/* Configure PWM Low from compare B value */
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aqctl_val = AQCTL_CBU_FRCLOW;
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aqctl_mask = AQCTL_CBU_MASK;
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} else {
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cmp_reg = CMPA;
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aqctl_reg = AQCTLA;
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/* Configure PWM Low from compare A value*/
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aqctl_val = AQCTL_CAU_FRCLOW;
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aqctl_mask = AQCTL_CAU_MASK;
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}
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/* Configure PWM High from period value and zero value */
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aqctl_val |= AQCTL_PRD_FRCHIGH | AQCTL_ZRO_FRCHIGH;
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aqctl_mask |= AQCTL_PRD_MASK | AQCTL_ZRO_MASK;
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ehrpwm_modify(pc->mmio_base, aqctl_reg, aqctl_mask, aqctl_val);
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ehrpwm_write(pc->mmio_base, cmp_reg, duty_cycles);
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}
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/*
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* period_ns = 10^9 * (ps_divval * period_cycles) / PWM_CLK_RATE
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* duty_ns = 10^9 * (ps_divval * duty_cycles) / PWM_CLK_RATE
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*/
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static int ehrpwm_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
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int duty_ns, int period_ns)
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{
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struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
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unsigned long long c;
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unsigned long period_cycles, duty_cycles;
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unsigned short ps_divval, tb_divval;
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if (period_ns < 0 || duty_ns < 0 || period_ns > NSEC_PER_SEC)
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return -ERANGE;
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c = pc->clk_rate;
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c = c * period_ns;
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do_div(c, NSEC_PER_SEC);
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period_cycles = (unsigned long)c;
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if (period_cycles < 1) {
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period_cycles = 1;
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duty_cycles = 1;
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} else {
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c = pc->clk_rate;
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c = c * duty_ns;
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do_div(c, NSEC_PER_SEC);
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duty_cycles = (unsigned long)c;
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}
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/* Configure clock prescaler to support Low frequency PWM wave */
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if (set_prescale_div(period_cycles/PERIOD_MAX, &ps_divval,
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&tb_divval)) {
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dev_err(chip->dev, "Unsupported values\n");
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return -EINVAL;
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}
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pm_runtime_get_sync(chip->dev);
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/* Update clock prescaler values */
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ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CLKDIV_MASK, tb_divval);
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/* Update period & duty cycle with presacler division */
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period_cycles = period_cycles / ps_divval;
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duty_cycles = duty_cycles / ps_divval;
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/* Configure shadow loading on Period register */
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ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_PRDLD_MASK, TBCTL_PRDLD_SHDW);
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ehrpwm_write(pc->mmio_base, TBPRD, period_cycles);
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/* Configure ehrpwm counter for up-count mode */
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ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CTRMODE_MASK,
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TBCTL_CTRMODE_UP);
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/* Configure the channel for duty cycle */
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configure_chans(pc, pwm->hwpwm, duty_cycles);
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pm_runtime_put_sync(chip->dev);
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return 0;
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}
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static int ehrpwm_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
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unsigned short aqcsfrc_val, aqcsfrc_mask;
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/* Leave clock enabled on enabling PWM */
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pm_runtime_get_sync(chip->dev);
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/* Disabling Action Qualifier on PWM output */
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if (pwm->hwpwm) {
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aqcsfrc_val = AQCSFRC_CSFB_FRCDIS;
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aqcsfrc_mask = AQCSFRC_CSFB_MASK;
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} else {
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aqcsfrc_val = AQCSFRC_CSFA_FRCDIS;
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aqcsfrc_mask = AQCSFRC_CSFA_MASK;
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}
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/* Changes to shadow mode */
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ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
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AQSFRC_RLDCSF_ZRO);
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ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);
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/* Enable time counter for free_run */
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ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_RUN_MASK, TBCTL_FREE_RUN);
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return 0;
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}
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static void ehrpwm_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
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unsigned short aqcsfrc_val, aqcsfrc_mask;
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/* Action Qualifier puts PWM output low forcefully */
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if (pwm->hwpwm) {
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aqcsfrc_val = AQCSFRC_CSFB_FRCLOW;
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aqcsfrc_mask = AQCSFRC_CSFB_MASK;
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} else {
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aqcsfrc_val = AQCSFRC_CSFA_FRCLOW;
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aqcsfrc_mask = AQCSFRC_CSFA_MASK;
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}
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/*
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* Changes to immediate action on Action Qualifier. This puts
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* Action Qualifier control on PWM output from next TBCLK
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*/
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ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
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AQSFRC_RLDCSF_IMDT);
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ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);
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/* Stop Time base counter */
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ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_RUN_MASK, TBCTL_STOP_NEXT);
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/* Disable clock on PWM disable */
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pm_runtime_put_sync(chip->dev);
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}
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static void ehrpwm_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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if (test_bit(PWMF_ENABLED, &pwm->flags)) {
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dev_warn(chip->dev, "Removing PWM device without disabling\n");
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pm_runtime_put_sync(chip->dev);
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}
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}
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static const struct pwm_ops ehrpwm_pwm_ops = {
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.free = ehrpwm_pwm_free,
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.config = ehrpwm_pwm_config,
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.enable = ehrpwm_pwm_enable,
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.disable = ehrpwm_pwm_disable,
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.owner = THIS_MODULE,
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};
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static int __devinit ehrpwm_pwm_probe(struct platform_device *pdev)
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{
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int ret;
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struct resource *r;
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struct clk *clk;
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struct ehrpwm_pwm_chip *pc;
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pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
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if (!pc) {
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dev_err(&pdev->dev, "failed to allocate memory\n");
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return -ENOMEM;
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}
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clk = devm_clk_get(&pdev->dev, "fck");
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if (IS_ERR(clk)) {
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dev_err(&pdev->dev, "failed to get clock\n");
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return PTR_ERR(clk);
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}
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pc->clk_rate = clk_get_rate(clk);
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if (!pc->clk_rate) {
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dev_err(&pdev->dev, "failed to get clock rate\n");
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return -EINVAL;
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}
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pc->chip.dev = &pdev->dev;
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pc->chip.ops = &ehrpwm_pwm_ops;
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pc->chip.base = -1;
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pc->chip.npwm = NUM_PWM_CHANNEL;
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r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!r) {
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dev_err(&pdev->dev, "no memory resource defined\n");
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return -ENODEV;
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}
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pc->mmio_base = devm_request_and_ioremap(&pdev->dev, r);
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if (!pc->mmio_base) {
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dev_err(&pdev->dev, "failed to ioremap() registers\n");
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return -EADDRNOTAVAIL;
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}
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ret = pwmchip_add(&pc->chip);
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if (ret < 0) {
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dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
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return ret;
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}
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pm_runtime_enable(&pdev->dev);
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platform_set_drvdata(pdev, pc);
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return 0;
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}
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static int __devexit ehrpwm_pwm_remove(struct platform_device *pdev)
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{
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struct ehrpwm_pwm_chip *pc = platform_get_drvdata(pdev);
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|
||||
pm_runtime_put_sync(&pdev->dev);
|
||||
pm_runtime_disable(&pdev->dev);
|
||||
return pwmchip_remove(&pc->chip);
|
||||
}
|
||||
|
||||
static struct platform_driver ehrpwm_pwm_driver = {
|
||||
.driver = {
|
||||
.name = "ehrpwm",
|
||||
},
|
||||
.probe = ehrpwm_pwm_probe,
|
||||
.remove = __devexit_p(ehrpwm_pwm_remove),
|
||||
};
|
||||
|
||||
module_platform_driver(ehrpwm_pwm_driver);
|
||||
|
||||
MODULE_DESCRIPTION("EHRPWM PWM driver");
|
||||
MODULE_AUTHOR("Texas Instruments");
|
||||
MODULE_LICENSE("GPL");
|
||||
Loading…
Reference in New Issue