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Message-ID: <1343215699-4575-3-git-send-email-avinashphilip@ti.com>
Date: Wed, 25 Jul 2012 16:58:19 +0530
From: "Philip, Avinash" <avinashphilip@...com>
To: <thierry.reding@...onic-design.de>
CC: <linux-kernel@...r.kernel.org>, <nsekhar@...com>,
<vaibhav.bedia@...com>, <gururaja.hebbar@...com>,
"Philip, Avinash" <avinashphilip@...com>
Subject: [PATCH v2 2/2] 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@...com>
Signed-off-by: Philip, Avinash <avinashphilip@...com>
---
:100644 100644 2840747... 371a36c... M drivers/pwm/Kconfig
:100644 100644 35fee43... e4b2c89... M drivers/pwm/Makefile
:000000 100644 0000000... 010d232... A drivers/pwm/pwm-tiehrpwm.c
drivers/pwm/Kconfig | 11 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-tiehrpwm.c | 411 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 423 insertions(+), 0 deletions(-)
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 2840747..371a36c 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -87,6 +87,17 @@ config PWM_TIECAP
To compile this driver as a module, choose M here: the module
will be called pwm-tiecap.
+config PWM_TIEHRPWM
+ tristate "EHRPWM PWM support"
+ depends on SOC_AM33XX
+
+ help
+ PWM driver support for the EHRPWM controller found on AM33XX
+ TI SOC
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-tiehrpwm.
+
config PWM_VT8500
tristate "vt8500 pwm support"
depends on ARCH_VT8500
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 35fee43..e4b2c89 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -7,4 +7,5 @@ obj-$(CONFIG_PWM_PXA) += pwm-pxa.o
obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o
obj-$(CONFIG_PWM_TIECAP) += pwm-tiecap.o
+obj-$(CONFIG_PWM_TIEHRPWM) += pwm-tiehrpwm.o
obj-$(CONFIG_PWM_VT8500) += pwm-vt8500.o
diff --git a/drivers/pwm/pwm-tiehrpwm.c b/drivers/pwm/pwm-tiehrpwm.c
new file mode 100644
index 0000000..010d232
--- /dev/null
+++ b/drivers/pwm/pwm-tiehrpwm.c
@@ -0,0 +1,411 @@
+/*
+ * 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>
+
+/* 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 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_pwm_chip {
+ struct pwm_chip chip;
+ unsigned int clk_rate;
+ void __iomem *mmio_base;
+};
+
+static inline struct ehrpwm_pwm_chip *to_ehrpwm_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct ehrpwm_pwm_chip, chip);
+}
+
+static void ehrpwm_write(void *base, int offset, unsigned int val)
+{
+ writew(val & 0xFFFF, base + offset);
+}
+
+static void ehrpwm_modify(void *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_chans(struct ehrpwm_pwm_chip *pc, int chan,
+ unsigned long duty_cycles)
+{
+ int cmp_reg, aqctl_reg;
+ unsigned short aqctl_val, aqctl_mask;
+
+ /*
+ * Channels can be configured from action qualifier module.
+ * Channel 0 configured with compare A register and for
+ * up-counter mode.
+ * Channel 1 configured with compare B register and for
+ * up-counter mode.
+ */
+ if (chan == 1) {
+ aqctl_reg = AQCTLB;
+ cmp_reg = CMPB;
+ /* Configure PWM Low from compare B value */
+ aqctl_val = AQCTL_CBU_FRCLOW;
+ aqctl_mask = AQCTL_CBU_MASK;
+ } else {
+ cmp_reg = CMPA;
+ aqctl_reg = AQCTLA;
+ /* Configure PWM Low from compare A value*/
+ aqctl_val = AQCTL_CAU_FRCLOW;
+ aqctl_mask = AQCTL_CAU_MASK;
+ }
+
+ /* Configure PWM High from period value and zero value */
+ aqctl_val |= AQCTL_PRD_FRCHIGH | AQCTL_ZRO_FRCHIGH;
+ aqctl_mask |= AQCTL_PRD_MASK | AQCTL_ZRO_MASK;
+ ehrpwm_modify(pc->mmio_base, aqctl_reg, aqctl_mask, aqctl_val);
+
+ ehrpwm_write(pc->mmio_base, cmp_reg, duty_cycles);
+}
+
+/*
+ * 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;
+
+ if (period_ns < 0 || duty_ns < 0 || 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;
+ }
+
+ /* 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);
+
+ /* Configure the channel for duty cycle */
+ configure_chans(pc, pwm->hwpwm, duty_cycles);
+ pm_runtime_put_sync(chip->dev);
+ 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;
+
+ /* 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);
+
+ /* 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);
+
+ /* 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)
+{
+ if (test_bit(PWMF_ENABLED, &pwm->flags)) {
+ dev_warn(chip->dev, "Removing PWM device without disabling\n");
+ pm_runtime_put_sync(chip->dev);
+ }
+}
+
+static const struct pwm_ops ehrpwm_pwm_ops = {
+ .free = ehrpwm_pwm_free,
+ .config = ehrpwm_pwm_config,
+ .enable = ehrpwm_pwm_enable,
+ .disable = ehrpwm_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+static int __devinit ehrpwm_pwm_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct resource *r;
+ struct clk *clk;
+ struct ehrpwm_pwm_chip *pc;
+
+ pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
+ if (!pc) {
+ dev_err(&pdev->dev, "failed to allocate memory\n");
+ 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.base = -1;
+ pc->chip.npwm = NUM_PWM_CHANNEL;
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!r) {
+ dev_err(&pdev->dev, "no memory resource defined\n");
+ return -ENODEV;
+ }
+
+ pc->mmio_base = devm_request_and_ioremap(&pdev->dev, r);
+ if (!pc->mmio_base) {
+ dev_err(&pdev->dev, "failed to ioremap() registers\n");
+ return -EADDRNOTAVAIL;
+ }
+
+ 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 __devexit ehrpwm_pwm_remove(struct platform_device *pdev)
+{
+ struct ehrpwm_pwm_chip *pc = platform_get_drvdata(pdev);
+
+ 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");
--
1.7.1
--
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