[PATCH 1/1] pwm: atmel: add Timer Counter Block PWM driver
Boris BREZILLON
linux-arm at overkiz.com
Thu Dec 6 11:45:23 EST 2012
Add TCB PWM driver.
Add device tree binding.
Signed-off-by: Boris BREZILLON <linux-arm at overkiz.com>
--
create mode 100644 Documentation/devicetree/bindings/pwm/atmel-tcb-pwm.txt
create mode 100644 drivers/pwm/pwm-atmel-tcb.c
diff --git a/Documentation/devicetree/bindings/pwm/atmel-tcb-pwm.txt b/Documentation/devicetree/bindings/pwm/atmel-tcb-pwm.txt
new file mode 100644
index 0000000..7644889
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/atmel-tcb-pwm.txt
@@ -0,0 +1,15 @@
+Atmel TCB PWM controller
+
+Required properties:
+- compatible: should be "atmel,tcb-pwm"
+- #pwm-cells: should be 2. The first cell specifies the per-chip index
+ of the PWM to use and the second cell is the period in nanoseconds.
+- atmel,tc-block: the Timer Counter block to use as a PWM chip.
+
+Example:
+
+pwm: pwm at 80064000 {
+ compatible = "fsl,imx28-pwm", "fsl,imx23-pwm";
+ #pwm-cells = <2>;
+ atmel,tc-block = <1>;
+};
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index e513cd9..bda52f7 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -37,6 +37,14 @@ config PWM_AB8500
To compile this driver as a module, choose M here: the module
will be called pwm-ab8500.
+config PWM_ATMEL_TCB
+ bool "TC Block PWM"
+ depends on ATMEL_TCLIB
+ select HAVE_PWM
+ default y
+ help
+ Select this to get 6 PWM devices.
+
config PWM_BFIN
tristate "Blackfin PWM support"
depends on BFIN_GPTIMERS
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 62a2963..94ba21e 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -1,5 +1,6 @@
obj-$(CONFIG_PWM) += core.o
obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o
+obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o
obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o
obj-$(CONFIG_PWM_IMX) += pwm-imx.o
obj-$(CONFIG_PWM_JZ4740) += pwm-jz4740.o
diff --git a/drivers/pwm/pwm-atmel-tcb.c b/drivers/pwm/pwm-atmel-tcb.c
new file mode 100644
index 0000000..d5a87cc
--- /dev/null
+++ b/drivers/pwm/pwm-atmel-tcb.c
@@ -0,0 +1,335 @@
+/*
+ * Copyright (C) Overkiz SAS 2012
+ *
+ * Author: Boris BREZILLON <b.brezillon at overkiz.com>
+ * License terms: GNU General Public License (GPL) version 2
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/atmel_tc.h>
+#include <linux/pwm.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
+
+#define NPWM 6
+
+struct atmel_tcb_pwm_device {
+ u8 polarity : 1;
+ u8 clk : 3;
+ u32 duty;
+ u32 period;
+};
+
+struct atmel_tcb_pwm_chip {
+ struct pwm_chip chip;
+ spinlock_t lock;
+ struct atmel_tc *tc;
+ struct atmel_tcb_pwm_device pwms[NPWM];
+};
+
+static inline struct atmel_tcb_pwm_chip *to_atmel_tcb_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct atmel_tcb_pwm_chip, chip);
+}
+
+static int atmel_tcb_pwm_set_polarity (struct pwm_chip *chip, struct pwm_device *pwm,
+ enum pwm_polarity polarity)
+{
+ struct atmel_tcb_pwm_device *tcbpwm =
+ (struct atmel_tcb_pwm_device *)pwm_get_chip_data(pwm);
+
+ tcbpwm->polarity = polarity;
+
+ return 0;
+}
+
+static int atmel_tcb_pwm_request (struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct atmel_tcb_pwm_chip *tcbpwmc = to_atmel_tcb_pwm_chip(chip);
+ struct atmel_tcb_pwm_device *tcbpwm = &(tcbpwmc->pwms[pwm->hwpwm]);
+ struct atmel_tc *tc = tcbpwmc->tc;
+ void __iomem *regs = tc->regs;
+ u32 reg;
+
+ pwm_set_chip_data(pwm, tcbpwm);
+ tcbpwm->polarity = PWM_POLARITY_NORMAL;
+ tcbpwm->duty = 0;
+ tcbpwm->period = 0;
+ tcbpwm->clk = 0;
+ spin_lock(&tcbpwmc->lock);
+ reg = __raw_readl (regs + ATMEL_TC_REG(pwm->hwpwm / 2, CMR));
+ if (reg & ATMEL_TC_WAVE) {
+ tcbpwm->duty = __raw_readl (regs + ((pwm->hwpwm % 2) ?
+ ATMEL_TC_REG(pwm->hwpwm / 2, RB) :
+ ATMEL_TC_REG(pwm->hwpwm / 2, RA)));
+
+
+ tcbpwm->clk = reg & ATMEL_TC_TCCLKS;
+ tcbpwm->period = __raw_readl (regs + ATMEL_TC_REG(pwm->hwpwm / 2, RC));
+ reg &= (ATMEL_TC_TCCLKS |
+ ATMEL_TC_ACPA | ATMEL_TC_ACPC | ATMEL_TC_AEEVT | ATMEL_TC_ASWTRG |
+ ATMEL_TC_BCPB | ATMEL_TC_BCPC | ATMEL_TC_BEEVT | ATMEL_TC_BSWTRG);
+ }
+ else
+ reg = 0;
+ reg |= ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO | ATMEL_TC_EEVT_XC0;
+ __raw_writel (reg, regs + ATMEL_TC_REG(pwm->hwpwm / 2, CMR));
+ spin_unlock(&tcbpwmc->lock);
+
+ clk_enable (tc->clk[pwm->hwpwm / 2]);
+
+ return 0;
+}
+
+static void atmel_tcb_pwm_free (struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct atmel_tcb_pwm_chip *tcbpwmc = to_atmel_tcb_pwm_chip(chip);
+ struct atmel_tc *tc = tcbpwmc->tc;
+
+ clk_disable (tc->clk[pwm->hwpwm / 2]);
+}
+
+static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct atmel_tcb_pwm_chip *tcbpwmc = to_atmel_tcb_pwm_chip(chip);
+ struct atmel_tcb_pwm_device *tcbpwm =
+ (struct atmel_tcb_pwm_device *)pwm_get_chip_data(pwm);
+ struct atmel_tc *tc = tcbpwmc->tc;
+ void __iomem *regs = tc->regs;
+ u32 reg;
+ u32 cmr = 0;
+ u8 shift = pwm->hwpwm % 2 ? 8 : 0;
+ enum pwm_polarity polarity = tcbpwm->polarity;
+
+ if (tcbpwm->duty == 0)
+ polarity = !polarity;
+
+ if (polarity)
+ cmr |= ATMEL_TC_ASWTRG_CLEAR;
+ else
+ cmr |= ATMEL_TC_ASWTRG_SET;
+
+ cmr <<= shift;
+
+ spin_lock(&tcbpwmc->lock);
+ reg = __raw_readl(regs + ATMEL_TC_REG(pwm->hwpwm / 2, CMR));
+ reg &= ~((ATMEL_TC_ACPA | ATMEL_TC_ACPC | ATMEL_TC_AEEVT | ATMEL_TC_BSWTRG) << shift);
+ reg |= cmr;
+ __raw_writel (reg, regs + ATMEL_TC_REG(pwm->hwpwm / 2, CMR));
+ __raw_writel (ATMEL_TC_SWTRG, regs + ATMEL_TC_REG(pwm->hwpwm / 2, CCR));
+ if (!(reg & (ATMEL_TC_ACPC | ATMEL_TC_BCPC)))
+ __raw_writel(ATMEL_TC_SWTRG | ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(pwm->hwpwm / 2, CCR));
+ else
+ __raw_writel (ATMEL_TC_SWTRG, regs + ATMEL_TC_REG(pwm->hwpwm / 2, CCR));
+ spin_unlock(&tcbpwmc->lock);
+}
+
+static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct atmel_tcb_pwm_chip *tcbpwmc = to_atmel_tcb_pwm_chip(chip);
+ struct atmel_tcb_pwm_device *tcbpwm =
+ (struct atmel_tcb_pwm_device *)pwm_get_chip_data(pwm);
+ struct atmel_tc *tc = tcbpwmc->tc;
+ void __iomem *regs = tc->regs;
+ u32 reg;
+ u32 cmr = 0;
+ u8 shift = pwm->hwpwm % 2 ? 8 : 0;
+ enum pwm_polarity polarity = tcbpwm->polarity;
+
+ if (tcbpwm->duty == 0)
+ polarity = !polarity;
+
+ if (polarity)
+ cmr |= ATMEL_TC_ASWTRG_CLEAR;
+ else
+ cmr |= ATMEL_TC_ASWTRG_SET;
+
+ if (tcbpwm->duty != tcbpwm->period && tcbpwm->duty > 0) {
+ if (polarity)
+ cmr |= ATMEL_TC_ACPA_SET | ATMEL_TC_ACPC_CLEAR;
+ else
+ cmr |= ATMEL_TC_ACPA_CLEAR | ATMEL_TC_ACPC_SET;
+ }
+
+ cmr <<= shift;
+ cmr |= tcbpwm->clk;
+
+ spin_lock(&tcbpwmc->lock);
+ reg = __raw_readl(regs + ATMEL_TC_REG(pwm->hwpwm / 2, CMR));
+ reg &= ~(((ATMEL_TC_ACPA |
+ ATMEL_TC_ACPC |
+ ATMEL_TC_AEEVT |
+ ATMEL_TC_ASWTRG) << shift) |
+ ATMEL_TC_TCCLKS);
+ reg |= cmr;
+ __raw_writel (reg, regs + ATMEL_TC_REG(pwm->hwpwm / 2, CMR));
+ __raw_writel(tcbpwm->duty, regs + ((pwm->hwpwm % 2) ? ATMEL_TC_REG(pwm->hwpwm / 2, RB) : ATMEL_TC_REG(pwm->hwpwm / 2, RA)));
+ __raw_writel(tcbpwm->period, regs + ATMEL_TC_REG(pwm->hwpwm / 2, RC));
+ __raw_writel (ATMEL_TC_CLKEN | ATMEL_TC_SWTRG, regs + ATMEL_TC_REG(pwm->hwpwm / 2, CCR));
+ spin_unlock(&tcbpwmc->lock);
+ return 0;
+}
+
+static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct atmel_tcb_pwm_chip *tcbpwmc = to_atmel_tcb_pwm_chip(chip);
+ struct atmel_tcb_pwm_device *tcbpwm =
+ (struct atmel_tcb_pwm_device *)pwm_get_chip_data(pwm);
+ struct atmel_tcb_pwm_device *atcbpwm = &(tcbpwmc->pwms[pwm->hwpwm % 2 ? pwm->hwpwm - 1 : pwm->hwpwm + 1]);
+ struct atmel_tc *tc = tcbpwmc->tc;
+ int i;
+ int slowclk = 0;
+ u32 period;
+ u32 rate = clk_get_rate(tc->clk[pwm->hwpwm / 2]);
+ u64 min;
+ u64 max;
+ u64 duty;
+
+ for (i = 0; i < 5; ++i) {
+ if (atmel_tc_divisors[i] == 0) {
+ slowclk = i;
+ continue;
+ }
+ min = div_u64 (1000000000, div_u64 (rate, atmel_tc_divisors[i]));
+ max = min << tc->tcb_config->counter_width;
+ if (max >= period_ns)
+ break;
+ }
+
+ if (i == 5) {
+ i = slowclk;
+ rate = 32768;
+ min = div_u64 (1000000000, rate);
+ max = min << 16;
+
+ if (max < period_ns)
+ return -ERANGE;
+ }
+
+ duty = div_u64 (duty_ns, min);
+ duty &= ((u64)(1 << tc->tcb_config->counter_width) - 1);
+
+ period = div_u64 (period_ns, min);
+ period &= ((u64)(1 << tc->tcb_config->counter_width) - 1);
+
+ if ((atcbpwm->duty > 0 && atcbpwm->duty != atcbpwm->period) &&
+ (atcbpwm->clk != i || atcbpwm->period != period)) {
+ dev_err(chip->dev, "failed to configure period_ns\n");
+ return -EINVAL;
+ }
+
+ tcbpwm->period = period;
+ tcbpwm->clk = i;
+ tcbpwm->duty = duty;
+
+ if (test_bit(PWMF_ENABLED, &pwm->flags))
+ atmel_tcb_pwm_enable(chip, pwm);
+
+ return 0;
+}
+
+static const struct pwm_ops atmel_tcb_pwm_ops = {
+ .set_polarity = atmel_tcb_pwm_set_polarity,
+ .request = atmel_tcb_pwm_request,
+ .free = atmel_tcb_pwm_free,
+ .config = atmel_tcb_pwm_config,
+ .enable = atmel_tcb_pwm_enable,
+ .disable = atmel_tcb_pwm_disable,
+};
+
+static int __devinit atmel_tcb_pwm_probe(struct platform_device *pdev)
+{
+ struct atmel_tcb_pwm_chip *tcbpwm;
+ struct device_node *np = pdev->dev.of_node;
+ struct atmel_tc *tc;
+ int err;
+ int tcblock;
+
+
+ err = of_property_read_u32(np, "tc-block", &tcblock);
+ if (err < 0) {
+ dev_err(&pdev->dev,
+ "failed to get tc block number from device tree (error: %d)\n", err);
+ return err;
+ }
+
+ tc = atmel_tc_alloc(tcblock, "tcb-pwm");
+ if (tc == NULL) {
+ dev_err(&pdev->dev, "failed to allocate Timer Counter Block\n");
+ return -ENOMEM;
+ }
+
+ tcbpwm = kzalloc(sizeof(*tcbpwm), GFP_KERNEL);
+ if (tcbpwm == NULL) {
+ dev_err(&pdev->dev, "failed to allocate memory\n");
+ return -ENOMEM;
+ }
+
+ tcbpwm->chip.dev = &pdev->dev;
+ tcbpwm->chip.ops = &atmel_tcb_pwm_ops;
+ tcbpwm->chip.base = pdev->id;
+ tcbpwm->chip.npwm = NPWM;
+ tcbpwm->tc = tc;
+
+ spin_lock_init(&tcbpwm->lock);
+
+ err = pwmchip_add(&tcbpwm->chip);
+ if (err < 0) {
+ kfree(tcbpwm);
+ return err;
+ }
+
+ dev_dbg(&pdev->dev, "pwm probe successful\n");
+ platform_set_drvdata(pdev, tcbpwm);
+
+ return 0;
+}
+
+static int __devexit atmel_tcb_pwm_remove(struct platform_device *pdev)
+{
+ struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev);
+ int err;
+
+ err = pwmchip_remove(&tcbpwm->chip);
+ if (err < 0)
+ return err;
+
+ atmel_tc_free(tcbpwm->tc);
+
+ dev_dbg(&pdev->dev, "pwm driver removed\n");
+ kfree(tcbpwm);
+
+ return 0;
+}
+
+static struct of_device_id atmel_tcb_pwm_dt_ids[] = {
+ { .compatible = "atmel,tcb-pwm", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mxs_pwm_dt_ids);
+
+static struct platform_driver atmel_tcb_pwm_driver = {
+ .driver = {
+ .name = "atmel-tcb-pwm",
+ .of_match_table = of_match_ptr(atmel_tcb_pwm_dt_ids),
+ },
+ .probe = atmel_tcb_pwm_probe,
+ .remove = __devexit_p(atmel_tcb_pwm_remove),
+};
+module_platform_driver(atmel_tcb_pwm_driver);
+
+MODULE_AUTHOR("Boris BREZILLON <b.brezillon at overkiz.com>");
+MODULE_DESCRIPTION("Atmel Timer Counter Pulse Width Modulation Driver");
+MODULE_ALIAS("platform:atmel-tcb-pwm");
+MODULE_LICENSE("GPL v2");
--
1.7.0.4
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