Re: [PATCH 1/1] pwm: atmel: add Timer Counter Block PWM driver

From: Jean-Christophe PLAGNIOL-VILLARD
Date: Thu Dec 13 2012 - 07:22:01 EST

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On 17:45 Thu 06 Dec , Boris BREZILLON wrote:
> Add TCB PWM driver.
> Add device tree binding.
>
> Signed-off-by: Boris BREZILLON <linux-arm@xxxxxxxxxxx>
> --
> 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@80064000 {
> + compatible = "fsl,imx28-pwm", "fsl,imx23-pwm";
are you sure?
> + #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
not 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@xxxxxxxxxxx>
> + * 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;
no need to optimise that much
> + 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];
need to be aloocated
> +};
> +
> +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));
no space before (
> + 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);
devm

I'll check more in detail later the tc part

Best Regards,
J.
> + 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@xxxxxxxxxxx>");
> +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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