Add Atmel PWM controller driver based on PWM framework.
This is the basic function implementation of Atmel PWM controller.
It can work with PWM based led and backlight.
Signed-off-by: Bo Shen <[email protected]>
---
Changes in v5:
- call clk_disable directly, if so, it won't cause more than one channel
enabled, the clock can not be disabled.
Changes in v4:
- check the return value of clk_prepare()
- change channel register size as constant
Changes in v3:
- change compatible string from "atmel,sama5-pwm" to "atmel,sama5d3-pwm"
- Add PWM led example in binding documentation
- Using micro replace hard code
Changes in v2:
- Address the comments from Thierry Reding
.../devicetree/bindings/pwm/atmel-pwm.txt | 41 +++
drivers/pwm/Kconfig | 9 +
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-atmel.c | 344 ++++++++++++++++++++
4 files changed, 395 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pwm/atmel-pwm.txt
create mode 100644 drivers/pwm/pwm-atmel.c
diff --git a/Documentation/devicetree/bindings/pwm/atmel-pwm.txt b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt
new file mode 100644
index 0000000..1c1a5fa
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt
@@ -0,0 +1,41 @@
+Atmel PWM controller
+
+Required properties:
+ - compatible: should be one of:
+ - "atmel,at91sam9rl-pwm"
+ - "atmel,sama5d3-pwm"
+ - reg: physical base address and length of the controller's registers
+ - #pwm-cells: Should be 3. See pwm.txt in this directory for a
+ description of the cells format
+
+Example:
+
+ pwm0: pwm@f8034000 {
+ compatible = "atmel,at91sam9rl-pwm";
+ reg = <0xf8034000 0x400>;
+ #pwm-cells = <3>;
+ };
+
+The following the pwm led based example:
+
+ pwm0: pwm@f8034000 {
+ compatible = "atmel,at91sam9rl-pwm";
+ reg = <0xf8034000 0x400>;
+ #pwm-cells = <3>;
+ };
+
+ pwdleds {
+ compatible = "pwm-leds";
+
+ d1 {
+ label = "d1";
+ pwms = <&pwm0 3 5000 0>
+ max-brightness = <255>;
+ };
+
+ d2 {
+ label = "d2";
+ pwms = <&pwm0 1 5000 1>
+ max-brightness = <255>;
+ };
+ };
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 75840b5..54237b9 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -41,6 +41,15 @@ config PWM_AB8500
To compile this driver as a module, choose M here: the module
will be called pwm-ab8500.
+config PWM_ATMEL
+ tristate "Atmel PWM support"
+ depends on ARCH_AT91
+ help
+ Generic PWM framework driver for Atmel SoC.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-atmel.
+
config PWM_ATMEL_TCB
tristate "Atmel TC Block PWM support"
depends on ATMEL_TCLIB && OF
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 77a8c18..5b193f8 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -1,6 +1,7 @@
obj-$(CONFIG_PWM) += core.o
obj-$(CONFIG_PWM_SYSFS) += sysfs.o
obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o
+obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o
obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o
obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o
obj-$(CONFIG_PWM_IMX) += pwm-imx.o
diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
new file mode 100644
index 0000000..b4df36c
--- /dev/null
+++ b/drivers/pwm/pwm-atmel.c
@@ -0,0 +1,344 @@
+/*
+ * Driver for Atmel Pulse Width Modulation Controller
+ *
+ * Copyright (C) 2013 Atmel Corporation
+ * Bo Shen <[email protected]>
+ *
+ * Licensed under GPLv2.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+/* The following is global registers for PWM controller */
+#define PWM_ENA 0x04
+#define PWM_DIS 0x08
+#define PWM_SR 0x0C
+/* bit field in SR */
+#define PWM_SR_ALL_CH_ON 0x0F
+
+/* The following register is PWM channel related registers */
+#define PWM_CH_REG_OFFSET 0x200
+#define PWM_CH_REG_SIZE 0x20
+
+#define PWM_CMR 0x0
+/* bit field in CMR */
+#define PWM_CMR_CPOL (1 << 9)
+#define PWM_CMR_UPD_CDTY (1 << 10)
+
+/* The following registers for PWM v1 */
+#define PWMv1_CDTY 0x04
+#define PWMv1_CPRD 0x08
+#define PWMv1_CUPD 0x10
+
+/* The following registers for PWM v2 */
+#define PWMv2_CDTY 0x04
+#define PWMv2_CDTYUPD 0x08
+#define PWMv2_CPRD 0x0C
+#define PWMv2_CPRDUPD 0x10
+
+/* max value for duty and period */
+/*
+ * Although the duty and period register is 32 bit,
+ * however only the LSB 16 bits are significant.
+ */
+#define PWM_MAX_DTY 0xFFFF
+#define PWM_MAX_PRD 0xFFFF
+#define PRD_MAX_PRES 10
+
+struct atmel_pwm_chip {
+ struct pwm_chip chip;
+ struct clk *clk;
+ void __iomem *base;
+
+ void (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
+ int dty, int prd);
+};
+
+static inline struct atmel_pwm_chip *to_atmel_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct atmel_pwm_chip, chip);
+}
+
+static inline u32 atmel_pwm_readl(struct atmel_pwm_chip *chip,
+ unsigned long offset)
+{
+ return readl(chip->base + offset);
+}
+
+static inline void atmel_pwm_writel(struct atmel_pwm_chip *chip,
+ unsigned long offset, unsigned long val)
+{
+ writel(val, chip->base + offset);
+}
+
+static inline u32 atmel_pwm_ch_readl(struct atmel_pwm_chip *chip,
+ unsigned int ch, unsigned long offset)
+{
+ return readl(chip->base + PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE
+ + offset);
+}
+
+static inline void atmel_pwm_ch_writel(struct atmel_pwm_chip *chip,
+ unsigned int ch, unsigned long offset,
+ unsigned long val)
+{
+ writel(val, chip->base + PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE
+ + offset);
+}
+
+static int atmel_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
+ unsigned long clk_rate, prd, dty;
+ unsigned long long div;
+ int ret, pres = 0;
+
+ clk_rate = clk_get_rate(atmel_pwm->clk);
+ div = clk_rate;
+
+ /* Calculate the period cycles */
+ while (div > PWM_MAX_PRD) {
+ div = clk_rate / (1 << pres);
+ div = div * period_ns;
+ /* 1/Hz = 100000000 ns */
+ do_div(div, 1000000000);
+
+ if (pres++ > PRD_MAX_PRES) {
+ pr_err("PRES is bigger than maximum pre-scaler\n");
+ return -EINVAL;
+ }
+ }
+
+ /* Calculate the duty cycles */
+ prd = div;
+ div *= duty_ns;
+ do_div(div, period_ns);
+ dty = div;
+
+ ret = clk_enable(atmel_pwm->clk);
+ if (ret) {
+ pr_err("Failed to enable pwm clock\n");
+ return ret;
+ }
+
+ atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, pres);
+ atmel_pwm->config(chip, pwm, dty, prd);
+
+ clk_disable(atmel_pwm->clk);
+
+ return 0;
+}
+
+static void atmel_pwm_config_v1(struct pwm_chip *chip, struct pwm_device *pwm,
+ int dty, int prd)
+{
+ struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
+ unsigned int val;
+
+ /*
+ * If the PWM channel is disabled, write value to duty and period
+ * registers directly.
+ * If the PWM channel is enabled, using the update register, it needs
+ * to set bit 10 of CMR to 0
+ */
+ if (test_bit(PWMF_ENABLED, &pwm->flags)) {
+ atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CUPD, dty);
+
+ val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR);
+ val &= ~PWM_CMR_UPD_CDTY;
+ atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
+ } else {
+ atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CDTY, dty);
+ atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CPRD, prd);
+ }
+}
+
+static void atmel_pwm_config_v2(struct pwm_chip *chip, struct pwm_device *pwm,
+ int dty, int prd)
+{
+ struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
+
+ /*
+ * If the PWM channel is disabled, write value to duty and period
+ * registers directly.
+ * If the PWM channel is enabled, using the duty update register to
+ * update the value.
+ */
+ if (test_bit(PWMF_ENABLED, &pwm->flags)) {
+ atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CDTYUPD, dty);
+ } else {
+ atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CDTY, dty);
+ atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CPRD, prd);
+ }
+}
+
+static int atmel_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
+ enum pwm_polarity polarity)
+{
+ struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
+ u32 val = 0;
+ int ret;
+
+ ret = clk_enable(atmel_pwm->clk);
+ if (ret) {
+ pr_err("failed to enable pwm clock\n");
+ return ret;
+ }
+
+ if (polarity == PWM_POLARITY_NORMAL)
+ val &= ~PWM_CMR_CPOL;
+ else
+ val |= PWM_CMR_CPOL;
+
+ atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
+
+ clk_disable(atmel_pwm->clk);
+
+ return 0;
+}
+
+static int atmel_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
+ int ret;
+
+ ret = clk_enable(atmel_pwm->clk);
+ if (ret) {
+ pr_err("failed to enable pwm clock\n");
+ return ret;
+ }
+
+ atmel_pwm_writel(atmel_pwm, PWM_ENA, 1 << pwm->hwpwm);
+
+ return 0;
+}
+
+static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
+
+ atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm);
+
+ clk_disable(atmel_pwm->clk);
+}
+
+static const struct pwm_ops atmel_pwm_ops = {
+ .config = atmel_pwm_config,
+ .set_polarity = atmel_pwm_set_polarity,
+ .enable = atmel_pwm_enable,
+ .disable = atmel_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+struct atmel_pwm_data {
+ void (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
+ int dty, int prd);
+};
+
+static const struct atmel_pwm_data atmel_pwm_data_v1 = {
+ .config = atmel_pwm_config_v1,
+};
+
+static const struct atmel_pwm_data atmel_pwm_data_v2 = {
+ .config = atmel_pwm_config_v2,
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id atmel_pwm_dt_ids[] = {
+ {
+ .compatible = "atmel,at91sam9rl-pwm",
+ .data = &atmel_pwm_data_v1,
+ }, {
+ .compatible = "atmel,sama5d3-pwm",
+ .data = &atmel_pwm_data_v2,
+ }, {
+ /* sentinel */
+ },
+};
+MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids);
+#endif
+
+static int atmel_pwm_probe(struct platform_device *pdev)
+{
+ const struct of_device_id *of_id =
+ of_match_device(atmel_pwm_dt_ids, &pdev->dev);
+ const struct atmel_pwm_data *data;
+ struct atmel_pwm_chip *atmel_pwm;
+ struct resource *res;
+ int ret;
+
+ atmel_pwm = devm_kzalloc(&pdev->dev, sizeof(*atmel_pwm), GFP_KERNEL);
+ if (!atmel_pwm)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+
+ atmel_pwm->base = devm_ioremap_resource(&pdev->dev, res);
+
+ atmel_pwm->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(atmel_pwm->clk))
+ return PTR_ERR(atmel_pwm->clk);
+
+ ret = clk_prepare(atmel_pwm->clk);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to prepare pwm clock\n");
+ return ret;
+ }
+
+ atmel_pwm->chip.dev = &pdev->dev;
+ atmel_pwm->chip.ops = &atmel_pwm_ops;
+ atmel_pwm->chip.of_xlate = of_pwm_xlate_with_flags;
+ atmel_pwm->chip.of_pwm_n_cells = 3;
+ atmel_pwm->chip.base = -1;
+ atmel_pwm->chip.npwm = 4;
+
+ data = of_id->data;
+ atmel_pwm->config = data->config;
+
+ ret = pwmchip_add(&atmel_pwm->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);
+ goto unprepare_clk;
+ }
+
+ platform_set_drvdata(pdev, atmel_pwm);
+
+unprepare_clk:
+ clk_unprepare(atmel_pwm->clk);
+ return ret;
+}
+
+static int atmel_pwm_remove(struct platform_device *pdev)
+{
+ struct atmel_pwm_chip *atmel_pwm = platform_get_drvdata(pdev);
+
+ clk_unprepare(atmel_pwm->clk);
+
+ return pwmchip_remove(&atmel_pwm->chip);
+}
+
+static struct platform_driver atmel_pwm_driver = {
+ .driver = {
+ .name = "atmel-pwm",
+ .of_match_table = of_match_ptr(atmel_pwm_dt_ids),
+ },
+ .probe = atmel_pwm_probe,
+ .remove = atmel_pwm_remove,
+};
+module_platform_driver(atmel_pwm_driver);
+
+MODULE_ALIAS("platform:atmel-pwm");
+MODULE_AUTHOR("Bo Shen <[email protected]>");
+MODULE_DESCRIPTION("Atmel PWM driver");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5
On 30/09/2013 11:10, Bo Shen wrote:
> Add Atmel PWM controller driver based on PWM framework.
>
> This is the basic function implementation of Atmel PWM controller.
> It can work with PWM based led and backlight.
>
> Signed-off-by: Bo Shen <[email protected]>
Acked-by: Alexandre Belloni <[email protected]>
>
> ---
> Changes in v5:
> - call clk_disable directly, if so, it won't cause more than one channel
> enabled, the clock can not be disabled.
>
> Changes in v4:
> - check the return value of clk_prepare()
> - change channel register size as constant
>
> Changes in v3:
> - change compatible string from "atmel,sama5-pwm" to "atmel,sama5d3-pwm"
> - Add PWM led example in binding documentation
> - Using micro replace hard code
>
> Changes in v2:
> - Address the comments from Thierry Reding
>
> .../devicetree/bindings/pwm/atmel-pwm.txt | 41 +++
> drivers/pwm/Kconfig | 9 +
> drivers/pwm/Makefile | 1 +
> drivers/pwm/pwm-atmel.c | 344 ++++++++++++++++++++
> 4 files changed, 395 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/pwm/atmel-pwm.txt
> create mode 100644 drivers/pwm/pwm-atmel.c
>
> diff --git a/Documentation/devicetree/bindings/pwm/atmel-pwm.txt b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt
> new file mode 100644
> index 0000000..1c1a5fa
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt
> @@ -0,0 +1,41 @@
> +Atmel PWM controller
> +
> +Required properties:
> + - compatible: should be one of:
> + - "atmel,at91sam9rl-pwm"
> + - "atmel,sama5d3-pwm"
> + - reg: physical base address and length of the controller's registers
> + - #pwm-cells: Should be 3. See pwm.txt in this directory for a
> + description of the cells format
> +
> +Example:
> +
> + pwm0: pwm@f8034000 {
> + compatible = "atmel,at91sam9rl-pwm";
> + reg = <0xf8034000 0x400>;
> + #pwm-cells = <3>;
> + };
> +
> +The following the pwm led based example:
> +
> + pwm0: pwm@f8034000 {
> + compatible = "atmel,at91sam9rl-pwm";
> + reg = <0xf8034000 0x400>;
> + #pwm-cells = <3>;
> + };
> +
> + pwdleds {
> + compatible = "pwm-leds";
> +
> + d1 {
> + label = "d1";
> + pwms = <&pwm0 3 5000 0>
> + max-brightness = <255>;
> + };
> +
> + d2 {
> + label = "d2";
> + pwms = <&pwm0 1 5000 1>
> + max-brightness = <255>;
> + };
> + };
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 75840b5..54237b9 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -41,6 +41,15 @@ config PWM_AB8500
> To compile this driver as a module, choose M here: the module
> will be called pwm-ab8500.
>
> +config PWM_ATMEL
> + tristate "Atmel PWM support"
> + depends on ARCH_AT91
> + help
> + Generic PWM framework driver for Atmel SoC.
> +
> + To compile this driver as a module, choose M here: the module
> + will be called pwm-atmel.
> +
> config PWM_ATMEL_TCB
> tristate "Atmel TC Block PWM support"
> depends on ATMEL_TCLIB && OF
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index 77a8c18..5b193f8 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -1,6 +1,7 @@
> obj-$(CONFIG_PWM) += core.o
> obj-$(CONFIG_PWM_SYSFS) += sysfs.o
> obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o
> +obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o
> obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o
> obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o
> obj-$(CONFIG_PWM_IMX) += pwm-imx.o
> diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
> new file mode 100644
> index 0000000..b4df36c
> --- /dev/null
> +++ b/drivers/pwm/pwm-atmel.c
> @@ -0,0 +1,344 @@
> +/*
> + * Driver for Atmel Pulse Width Modulation Controller
> + *
> + * Copyright (C) 2013 Atmel Corporation
> + * Bo Shen <[email protected]>
> + *
> + * Licensed under GPLv2.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/slab.h>
> +
> +/* The following is global registers for PWM controller */
> +#define PWM_ENA 0x04
> +#define PWM_DIS 0x08
> +#define PWM_SR 0x0C
> +/* bit field in SR */
> +#define PWM_SR_ALL_CH_ON 0x0F
> +
> +/* The following register is PWM channel related registers */
> +#define PWM_CH_REG_OFFSET 0x200
> +#define PWM_CH_REG_SIZE 0x20
> +
> +#define PWM_CMR 0x0
> +/* bit field in CMR */
> +#define PWM_CMR_CPOL (1 << 9)
> +#define PWM_CMR_UPD_CDTY (1 << 10)
> +
> +/* The following registers for PWM v1 */
> +#define PWMv1_CDTY 0x04
> +#define PWMv1_CPRD 0x08
> +#define PWMv1_CUPD 0x10
> +
> +/* The following registers for PWM v2 */
> +#define PWMv2_CDTY 0x04
> +#define PWMv2_CDTYUPD 0x08
> +#define PWMv2_CPRD 0x0C
> +#define PWMv2_CPRDUPD 0x10
> +
> +/* max value for duty and period */
> +/*
> + * Although the duty and period register is 32 bit,
> + * however only the LSB 16 bits are significant.
> + */
> +#define PWM_MAX_DTY 0xFFFF
> +#define PWM_MAX_PRD 0xFFFF
> +#define PRD_MAX_PRES 10
> +
> +struct atmel_pwm_chip {
> + struct pwm_chip chip;
> + struct clk *clk;
> + void __iomem *base;
> +
> + void (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
> + int dty, int prd);
> +};
> +
> +static inline struct atmel_pwm_chip *to_atmel_pwm_chip(struct pwm_chip *chip)
> +{
> + return container_of(chip, struct atmel_pwm_chip, chip);
> +}
> +
> +static inline u32 atmel_pwm_readl(struct atmel_pwm_chip *chip,
> + unsigned long offset)
> +{
> + return readl(chip->base + offset);
> +}
> +
> +static inline void atmel_pwm_writel(struct atmel_pwm_chip *chip,
> + unsigned long offset, unsigned long val)
> +{
> + writel(val, chip->base + offset);
> +}
> +
> +static inline u32 atmel_pwm_ch_readl(struct atmel_pwm_chip *chip,
> + unsigned int ch, unsigned long offset)
> +{
> + return readl(chip->base + PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE
> + + offset);
> +}
> +
> +static inline void atmel_pwm_ch_writel(struct atmel_pwm_chip *chip,
> + unsigned int ch, unsigned long offset,
> + unsigned long val)
> +{
> + writel(val, chip->base + PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE
> + + offset);
> +}
> +
> +static int atmel_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> + int duty_ns, int period_ns)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> + unsigned long clk_rate, prd, dty;
> + unsigned long long div;
> + int ret, pres = 0;
> +
> + clk_rate = clk_get_rate(atmel_pwm->clk);
> + div = clk_rate;
> +
> + /* Calculate the period cycles */
> + while (div > PWM_MAX_PRD) {
> + div = clk_rate / (1 << pres);
> + div = div * period_ns;
> + /* 1/Hz = 100000000 ns */
> + do_div(div, 1000000000);
> +
> + if (pres++ > PRD_MAX_PRES) {
> + pr_err("PRES is bigger than maximum pre-scaler\n");
> + return -EINVAL;
> + }
> + }
> +
> + /* Calculate the duty cycles */
> + prd = div;
> + div *= duty_ns;
> + do_div(div, period_ns);
> + dty = div;
> +
> + ret = clk_enable(atmel_pwm->clk);
> + if (ret) {
> + pr_err("Failed to enable pwm clock\n");
> + return ret;
> + }
> +
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, pres);
> + atmel_pwm->config(chip, pwm, dty, prd);
> +
> + clk_disable(atmel_pwm->clk);
> +
> + return 0;
> +}
> +
> +static void atmel_pwm_config_v1(struct pwm_chip *chip, struct pwm_device *pwm,
> + int dty, int prd)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> + unsigned int val;
> +
> + /*
> + * If the PWM channel is disabled, write value to duty and period
> + * registers directly.
> + * If the PWM channel is enabled, using the update register, it needs
> + * to set bit 10 of CMR to 0
> + */
> + if (test_bit(PWMF_ENABLED, &pwm->flags)) {
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CUPD, dty);
> +
> + val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR);
> + val &= ~PWM_CMR_UPD_CDTY;
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
> + } else {
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CDTY, dty);
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CPRD, prd);
> + }
> +}
> +
> +static void atmel_pwm_config_v2(struct pwm_chip *chip, struct pwm_device *pwm,
> + int dty, int prd)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> +
> + /*
> + * If the PWM channel is disabled, write value to duty and period
> + * registers directly.
> + * If the PWM channel is enabled, using the duty update register to
> + * update the value.
> + */
> + if (test_bit(PWMF_ENABLED, &pwm->flags)) {
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CDTYUPD, dty);
> + } else {
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CDTY, dty);
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CPRD, prd);
> + }
> +}
> +
> +static int atmel_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
> + enum pwm_polarity polarity)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> + u32 val = 0;
> + int ret;
> +
> + ret = clk_enable(atmel_pwm->clk);
> + if (ret) {
> + pr_err("failed to enable pwm clock\n");
> + return ret;
> + }
> +
> + if (polarity == PWM_POLARITY_NORMAL)
> + val &= ~PWM_CMR_CPOL;
> + else
> + val |= PWM_CMR_CPOL;
> +
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
> +
> + clk_disable(atmel_pwm->clk);
> +
> + return 0;
> +}
> +
> +static int atmel_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> + int ret;
> +
> + ret = clk_enable(atmel_pwm->clk);
> + if (ret) {
> + pr_err("failed to enable pwm clock\n");
> + return ret;
> + }
> +
> + atmel_pwm_writel(atmel_pwm, PWM_ENA, 1 << pwm->hwpwm);
> +
> + return 0;
> +}
> +
> +static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> +
> + atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm);
> +
> + clk_disable(atmel_pwm->clk);
> +}
> +
> +static const struct pwm_ops atmel_pwm_ops = {
> + .config = atmel_pwm_config,
> + .set_polarity = atmel_pwm_set_polarity,
> + .enable = atmel_pwm_enable,
> + .disable = atmel_pwm_disable,
> + .owner = THIS_MODULE,
> +};
> +
> +struct atmel_pwm_data {
> + void (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
> + int dty, int prd);
> +};
> +
> +static const struct atmel_pwm_data atmel_pwm_data_v1 = {
> + .config = atmel_pwm_config_v1,
> +};
> +
> +static const struct atmel_pwm_data atmel_pwm_data_v2 = {
> + .config = atmel_pwm_config_v2,
> +};
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id atmel_pwm_dt_ids[] = {
> + {
> + .compatible = "atmel,at91sam9rl-pwm",
> + .data = &atmel_pwm_data_v1,
> + }, {
> + .compatible = "atmel,sama5d3-pwm",
> + .data = &atmel_pwm_data_v2,
> + }, {
> + /* sentinel */
> + },
> +};
> +MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids);
> +#endif
> +
> +static int atmel_pwm_probe(struct platform_device *pdev)
> +{
> + const struct of_device_id *of_id =
> + of_match_device(atmel_pwm_dt_ids, &pdev->dev);
> + const struct atmel_pwm_data *data;
> + struct atmel_pwm_chip *atmel_pwm;
> + struct resource *res;
> + int ret;
> +
> + atmel_pwm = devm_kzalloc(&pdev->dev, sizeof(*atmel_pwm), GFP_KERNEL);
> + if (!atmel_pwm)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res)
> + return -ENODEV;
> +
> + atmel_pwm->base = devm_ioremap_resource(&pdev->dev, res);
> +
> + atmel_pwm->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(atmel_pwm->clk))
> + return PTR_ERR(atmel_pwm->clk);
> +
> + ret = clk_prepare(atmel_pwm->clk);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to prepare pwm clock\n");
> + return ret;
> + }
> +
> + atmel_pwm->chip.dev = &pdev->dev;
> + atmel_pwm->chip.ops = &atmel_pwm_ops;
> + atmel_pwm->chip.of_xlate = of_pwm_xlate_with_flags;
> + atmel_pwm->chip.of_pwm_n_cells = 3;
> + atmel_pwm->chip.base = -1;
> + atmel_pwm->chip.npwm = 4;
> +
> + data = of_id->data;
> + atmel_pwm->config = data->config;
> +
> + ret = pwmchip_add(&atmel_pwm->chip);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);
> + goto unprepare_clk;
> + }
> +
> + platform_set_drvdata(pdev, atmel_pwm);
> +
> +unprepare_clk:
> + clk_unprepare(atmel_pwm->clk);
> + return ret;
> +}
> +
> +static int atmel_pwm_remove(struct platform_device *pdev)
> +{
> + struct atmel_pwm_chip *atmel_pwm = platform_get_drvdata(pdev);
> +
> + clk_unprepare(atmel_pwm->clk);
> +
> + return pwmchip_remove(&atmel_pwm->chip);
> +}
> +
> +static struct platform_driver atmel_pwm_driver = {
> + .driver = {
> + .name = "atmel-pwm",
> + .of_match_table = of_match_ptr(atmel_pwm_dt_ids),
> + },
> + .probe = atmel_pwm_probe,
> + .remove = atmel_pwm_remove,
> +};
> +module_platform_driver(atmel_pwm_driver);
> +
> +MODULE_ALIAS("platform:atmel-pwm");
> +MODULE_AUTHOR("Bo Shen <[email protected]>");
> +MODULE_DESCRIPTION("Atmel PWM driver");
> +MODULE_LICENSE("GPL v2");
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
On Mon, Sep 30, 2013 at 05:10:40PM +0800, Bo Shen wrote:
> Add Atmel PWM controller driver based on PWM framework.
>
> This is the basic function implementation of Atmel PWM controller.
> It can work with PWM based led and backlight.
>
> Signed-off-by: Bo Shen <[email protected]>
>
> ---
> Changes in v5:
> - call clk_disable directly, if so, it won't cause more than one channel
> enabled, the clock can not be disabled.
>
> Changes in v4:
> - check the return value of clk_prepare()
> - change channel register size as constant
>
> Changes in v3:
> - change compatible string from "atmel,sama5-pwm" to "atmel,sama5d3-pwm"
> - Add PWM led example in binding documentation
> - Using micro replace hard code
>
> Changes in v2:
> - Address the comments from Thierry Reding
>
> .../devicetree/bindings/pwm/atmel-pwm.txt | 41 +++
> drivers/pwm/Kconfig | 9 +
> drivers/pwm/Makefile | 1 +
> drivers/pwm/pwm-atmel.c | 344 ++++++++++++++++++++
> 4 files changed, 395 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/pwm/atmel-pwm.txt
> create mode 100644 drivers/pwm/pwm-atmel.c
I haven't seen an Acked-by from the device tree bindings maintainers on
this. I've Cc'ed them, so hopefully one of them has time to review.
Thierry
> diff --git a/Documentation/devicetree/bindings/pwm/atmel-pwm.txt b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt
> new file mode 100644
> index 0000000..1c1a5fa
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt
> @@ -0,0 +1,41 @@
> +Atmel PWM controller
> +
> +Required properties:
> + - compatible: should be one of:
> + - "atmel,at91sam9rl-pwm"
> + - "atmel,sama5d3-pwm"
> + - reg: physical base address and length of the controller's registers
> + - #pwm-cells: Should be 3. See pwm.txt in this directory for a
> + description of the cells format
> +
> +Example:
> +
> + pwm0: pwm@f8034000 {
> + compatible = "atmel,at91sam9rl-pwm";
> + reg = <0xf8034000 0x400>;
> + #pwm-cells = <3>;
> + };
> +
> +The following the pwm led based example:
> +
> + pwm0: pwm@f8034000 {
> + compatible = "atmel,at91sam9rl-pwm";
> + reg = <0xf8034000 0x400>;
> + #pwm-cells = <3>;
> + };
> +
> + pwdleds {
> + compatible = "pwm-leds";
> +
> + d1 {
> + label = "d1";
> + pwms = <&pwm0 3 5000 0>
> + max-brightness = <255>;
> + };
> +
> + d2 {
> + label = "d2";
> + pwms = <&pwm0 1 5000 1>
> + max-brightness = <255>;
> + };
> + };
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 75840b5..54237b9 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -41,6 +41,15 @@ config PWM_AB8500
> To compile this driver as a module, choose M here: the module
> will be called pwm-ab8500.
>
> +config PWM_ATMEL
> + tristate "Atmel PWM support"
> + depends on ARCH_AT91
> + help
> + Generic PWM framework driver for Atmel SoC.
> +
> + To compile this driver as a module, choose M here: the module
> + will be called pwm-atmel.
> +
> config PWM_ATMEL_TCB
> tristate "Atmel TC Block PWM support"
> depends on ATMEL_TCLIB && OF
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index 77a8c18..5b193f8 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -1,6 +1,7 @@
> obj-$(CONFIG_PWM) += core.o
> obj-$(CONFIG_PWM_SYSFS) += sysfs.o
> obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o
> +obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o
> obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o
> obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o
> obj-$(CONFIG_PWM_IMX) += pwm-imx.o
> diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
> new file mode 100644
> index 0000000..b4df36c
> --- /dev/null
> +++ b/drivers/pwm/pwm-atmel.c
> @@ -0,0 +1,344 @@
> +/*
> + * Driver for Atmel Pulse Width Modulation Controller
> + *
> + * Copyright (C) 2013 Atmel Corporation
> + * Bo Shen <[email protected]>
> + *
> + * Licensed under GPLv2.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/slab.h>
> +
> +/* The following is global registers for PWM controller */
> +#define PWM_ENA 0x04
> +#define PWM_DIS 0x08
> +#define PWM_SR 0x0C
> +/* bit field in SR */
> +#define PWM_SR_ALL_CH_ON 0x0F
> +
> +/* The following register is PWM channel related registers */
> +#define PWM_CH_REG_OFFSET 0x200
> +#define PWM_CH_REG_SIZE 0x20
> +
> +#define PWM_CMR 0x0
> +/* bit field in CMR */
> +#define PWM_CMR_CPOL (1 << 9)
> +#define PWM_CMR_UPD_CDTY (1 << 10)
> +
> +/* The following registers for PWM v1 */
> +#define PWMv1_CDTY 0x04
> +#define PWMv1_CPRD 0x08
> +#define PWMv1_CUPD 0x10
> +
> +/* The following registers for PWM v2 */
> +#define PWMv2_CDTY 0x04
> +#define PWMv2_CDTYUPD 0x08
> +#define PWMv2_CPRD 0x0C
> +#define PWMv2_CPRDUPD 0x10
> +
> +/* max value for duty and period */
> +/*
> + * Although the duty and period register is 32 bit,
> + * however only the LSB 16 bits are significant.
> + */
> +#define PWM_MAX_DTY 0xFFFF
> +#define PWM_MAX_PRD 0xFFFF
> +#define PRD_MAX_PRES 10
> +
> +struct atmel_pwm_chip {
> + struct pwm_chip chip;
> + struct clk *clk;
> + void __iomem *base;
> +
> + void (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
> + int dty, int prd);
> +};
> +
> +static inline struct atmel_pwm_chip *to_atmel_pwm_chip(struct pwm_chip *chip)
> +{
> + return container_of(chip, struct atmel_pwm_chip, chip);
> +}
> +
> +static inline u32 atmel_pwm_readl(struct atmel_pwm_chip *chip,
> + unsigned long offset)
> +{
> + return readl(chip->base + offset);
> +}
> +
> +static inline void atmel_pwm_writel(struct atmel_pwm_chip *chip,
> + unsigned long offset, unsigned long val)
> +{
> + writel(val, chip->base + offset);
> +}
> +
> +static inline u32 atmel_pwm_ch_readl(struct atmel_pwm_chip *chip,
> + unsigned int ch, unsigned long offset)
> +{
> + return readl(chip->base + PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE
> + + offset);
> +}
> +
> +static inline void atmel_pwm_ch_writel(struct atmel_pwm_chip *chip,
> + unsigned int ch, unsigned long offset,
> + unsigned long val)
> +{
> + writel(val, chip->base + PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE
> + + offset);
> +}
> +
> +static int atmel_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> + int duty_ns, int period_ns)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> + unsigned long clk_rate, prd, dty;
> + unsigned long long div;
> + int ret, pres = 0;
> +
> + clk_rate = clk_get_rate(atmel_pwm->clk);
> + div = clk_rate;
> +
> + /* Calculate the period cycles */
> + while (div > PWM_MAX_PRD) {
> + div = clk_rate / (1 << pres);
> + div = div * period_ns;
> + /* 1/Hz = 100000000 ns */
> + do_div(div, 1000000000);
> +
> + if (pres++ > PRD_MAX_PRES) {
> + pr_err("PRES is bigger than maximum pre-scaler\n");
> + return -EINVAL;
> + }
> + }
> +
> + /* Calculate the duty cycles */
> + prd = div;
> + div *= duty_ns;
> + do_div(div, period_ns);
> + dty = div;
> +
> + ret = clk_enable(atmel_pwm->clk);
> + if (ret) {
> + pr_err("Failed to enable pwm clock\n");
> + return ret;
> + }
> +
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, pres);
> + atmel_pwm->config(chip, pwm, dty, prd);
> +
> + clk_disable(atmel_pwm->clk);
> +
> + return 0;
> +}
> +
> +static void atmel_pwm_config_v1(struct pwm_chip *chip, struct pwm_device *pwm,
> + int dty, int prd)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> + unsigned int val;
> +
> + /*
> + * If the PWM channel is disabled, write value to duty and period
> + * registers directly.
> + * If the PWM channel is enabled, using the update register, it needs
> + * to set bit 10 of CMR to 0
> + */
> + if (test_bit(PWMF_ENABLED, &pwm->flags)) {
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CUPD, dty);
> +
> + val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR);
> + val &= ~PWM_CMR_UPD_CDTY;
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
> + } else {
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CDTY, dty);
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CPRD, prd);
> + }
> +}
> +
> +static void atmel_pwm_config_v2(struct pwm_chip *chip, struct pwm_device *pwm,
> + int dty, int prd)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> +
> + /*
> + * If the PWM channel is disabled, write value to duty and period
> + * registers directly.
> + * If the PWM channel is enabled, using the duty update register to
> + * update the value.
> + */
> + if (test_bit(PWMF_ENABLED, &pwm->flags)) {
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CDTYUPD, dty);
> + } else {
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CDTY, dty);
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CPRD, prd);
> + }
> +}
> +
> +static int atmel_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
> + enum pwm_polarity polarity)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> + u32 val = 0;
> + int ret;
> +
> + ret = clk_enable(atmel_pwm->clk);
> + if (ret) {
> + pr_err("failed to enable pwm clock\n");
> + return ret;
> + }
> +
> + if (polarity == PWM_POLARITY_NORMAL)
> + val &= ~PWM_CMR_CPOL;
> + else
> + val |= PWM_CMR_CPOL;
> +
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
> +
> + clk_disable(atmel_pwm->clk);
> +
> + return 0;
> +}
> +
> +static int atmel_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> + int ret;
> +
> + ret = clk_enable(atmel_pwm->clk);
> + if (ret) {
> + pr_err("failed to enable pwm clock\n");
> + return ret;
> + }
> +
> + atmel_pwm_writel(atmel_pwm, PWM_ENA, 1 << pwm->hwpwm);
> +
> + return 0;
> +}
> +
> +static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> +
> + atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm);
> +
> + clk_disable(atmel_pwm->clk);
> +}
> +
> +static const struct pwm_ops atmel_pwm_ops = {
> + .config = atmel_pwm_config,
> + .set_polarity = atmel_pwm_set_polarity,
> + .enable = atmel_pwm_enable,
> + .disable = atmel_pwm_disable,
> + .owner = THIS_MODULE,
> +};
> +
> +struct atmel_pwm_data {
> + void (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
> + int dty, int prd);
> +};
> +
> +static const struct atmel_pwm_data atmel_pwm_data_v1 = {
> + .config = atmel_pwm_config_v1,
> +};
> +
> +static const struct atmel_pwm_data atmel_pwm_data_v2 = {
> + .config = atmel_pwm_config_v2,
> +};
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id atmel_pwm_dt_ids[] = {
> + {
> + .compatible = "atmel,at91sam9rl-pwm",
> + .data = &atmel_pwm_data_v1,
> + }, {
> + .compatible = "atmel,sama5d3-pwm",
> + .data = &atmel_pwm_data_v2,
> + }, {
> + /* sentinel */
> + },
> +};
> +MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids);
> +#endif
> +
> +static int atmel_pwm_probe(struct platform_device *pdev)
> +{
> + const struct of_device_id *of_id =
> + of_match_device(atmel_pwm_dt_ids, &pdev->dev);
> + const struct atmel_pwm_data *data;
> + struct atmel_pwm_chip *atmel_pwm;
> + struct resource *res;
> + int ret;
> +
> + atmel_pwm = devm_kzalloc(&pdev->dev, sizeof(*atmel_pwm), GFP_KERNEL);
> + if (!atmel_pwm)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res)
> + return -ENODEV;
> +
> + atmel_pwm->base = devm_ioremap_resource(&pdev->dev, res);
> +
> + atmel_pwm->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(atmel_pwm->clk))
> + return PTR_ERR(atmel_pwm->clk);
> +
> + ret = clk_prepare(atmel_pwm->clk);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to prepare pwm clock\n");
> + return ret;
> + }
> +
> + atmel_pwm->chip.dev = &pdev->dev;
> + atmel_pwm->chip.ops = &atmel_pwm_ops;
> + atmel_pwm->chip.of_xlate = of_pwm_xlate_with_flags;
> + atmel_pwm->chip.of_pwm_n_cells = 3;
> + atmel_pwm->chip.base = -1;
> + atmel_pwm->chip.npwm = 4;
> +
> + data = of_id->data;
> + atmel_pwm->config = data->config;
> +
> + ret = pwmchip_add(&atmel_pwm->chip);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);
> + goto unprepare_clk;
> + }
> +
> + platform_set_drvdata(pdev, atmel_pwm);
> +
> +unprepare_clk:
> + clk_unprepare(atmel_pwm->clk);
> + return ret;
> +}
> +
> +static int atmel_pwm_remove(struct platform_device *pdev)
> +{
> + struct atmel_pwm_chip *atmel_pwm = platform_get_drvdata(pdev);
> +
> + clk_unprepare(atmel_pwm->clk);
> +
> + return pwmchip_remove(&atmel_pwm->chip);
> +}
> +
> +static struct platform_driver atmel_pwm_driver = {
> + .driver = {
> + .name = "atmel-pwm",
> + .of_match_table = of_match_ptr(atmel_pwm_dt_ids),
> + },
> + .probe = atmel_pwm_probe,
> + .remove = atmel_pwm_remove,
> +};
> +module_platform_driver(atmel_pwm_driver);
> +
> +MODULE_ALIAS("platform:atmel-pwm");
> +MODULE_AUTHOR("Bo Shen <[email protected]>");
> +MODULE_DESCRIPTION("Atmel PWM driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.7.9.5
>
Hi All,
On 10/8/2013 21:17, Thierry Reding wrote:
> On Mon, Sep 30, 2013 at 05:10:40PM +0800, Bo Shen wrote:
>> Add Atmel PWM controller driver based on PWM framework.
>>
>> This is the basic function implementation of Atmel PWM controller.
>> It can work with PWM based led and backlight.
>>
>> Signed-off-by: Bo Shen <[email protected]>
>>
>> ---
>> Changes in v5:
>> - call clk_disable directly, if so, it won't cause more than one channel
>> enabled, the clock can not be disabled.
>>
>> Changes in v4:
>> - check the return value of clk_prepare()
>> - change channel register size as constant
>>
>> Changes in v3:
>> - change compatible string from "atmel,sama5-pwm" to "atmel,sama5d3-pwm"
>> - Add PWM led example in binding documentation
>> - Using micro replace hard code
>>
>> Changes in v2:
>> - Address the comments from Thierry Reding
>>
>> .../devicetree/bindings/pwm/atmel-pwm.txt | 41 +++
>> drivers/pwm/Kconfig | 9 +
>> drivers/pwm/Makefile | 1 +
>> drivers/pwm/pwm-atmel.c | 344 ++++++++++++++++++++
>> 4 files changed, 395 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/pwm/atmel-pwm.txt
>> create mode 100644 drivers/pwm/pwm-atmel.c
>
> I haven't seen an Acked-by from the device tree bindings maintainers on
> this. I've Cc'ed them, so hopefully one of them has time to review.
Any comments?
Best Regards,
Bo Shen
On 22/10/2013 12:13, Bo Shen :
> Hi All,
>
> On 10/8/2013 21:17, Thierry Reding wrote:
>> On Mon, Sep 30, 2013 at 05:10:40PM +0800, Bo Shen wrote:
>>> Add Atmel PWM controller driver based on PWM framework.
>>>
>>> This is the basic function implementation of Atmel PWM controller.
>>> It can work with PWM based led and backlight.
>>>
>>> Signed-off-by: Bo Shen <[email protected]>
>>>
>>> ---
>>> Changes in v5:
>>> - call clk_disable directly, if so, it won't cause more than one channel
>>> enabled, the clock can not be disabled.
>>>
>>> Changes in v4:
>>> - check the return value of clk_prepare()
>>> - change channel register size as constant
>>>
>>> Changes in v3:
>>> - change compatible string from "atmel,sama5-pwm" to "atmel,sama5d3-pwm"
>>> - Add PWM led example in binding documentation
>>> - Using micro replace hard code
>>>
>>> Changes in v2:
>>> - Address the comments from Thierry Reding
>>>
>>> .../devicetree/bindings/pwm/atmel-pwm.txt | 41 +++
>>> drivers/pwm/Kconfig | 9 +
>>> drivers/pwm/Makefile | 1 +
>>> drivers/pwm/pwm-atmel.c | 344 ++++++++++++++++++++
>>> 4 files changed, 395 insertions(+)
>>> create mode 100644 Documentation/devicetree/bindings/pwm/atmel-pwm.txt
>>> create mode 100644 drivers/pwm/pwm-atmel.c
>>
>> I haven't seen an Acked-by from the device tree bindings maintainers on
>> this. I've Cc'ed them, so hopefully one of them has time to review.
>
> Any comments?
As a recommendation from the recent Kernel Summit stated, you will have
to separate the binding itself from the driver and associated code.
Simply send the binding documentation to the DT maintainers but still
keep the two patches linked together in a series (but without putting DT
maintainers nor the DT mailing-list in CC of the non-documentation patches).
This way you may have more chances to get feedback.
Thanks, bye,
--
Nicolas Ferre
Hi Nicolas,
On 10/28/2013 10:49 PM, Nicolas Ferre wrote:
> On 22/10/2013 12:13, Bo Shen :
>> Hi All,
>>
>> On 10/8/2013 21:17, Thierry Reding wrote:
>>> On Mon, Sep 30, 2013 at 05:10:40PM +0800, Bo Shen wrote:
>>>> Add Atmel PWM controller driver based on PWM framework.
>>>>
>>>> This is the basic function implementation of Atmel PWM controller.
>>>> It can work with PWM based led and backlight.
>>>>
>>>> Signed-off-by: Bo Shen <[email protected]>
>>>>
>>>> ---
>>>> Changes in v5:
>>>> - call clk_disable directly, if so, it won't cause more than one
>>>> channel
>>>> enabled, the clock can not be disabled.
>>>>
>>>> Changes in v4:
>>>> - check the return value of clk_prepare()
>>>> - change channel register size as constant
>>>>
>>>> Changes in v3:
>>>> - change compatible string from "atmel,sama5-pwm" to
>>>> "atmel,sama5d3-pwm"
>>>> - Add PWM led example in binding documentation
>>>> - Using micro replace hard code
>>>>
>>>> Changes in v2:
>>>> - Address the comments from Thierry Reding
>>>>
>>>> .../devicetree/bindings/pwm/atmel-pwm.txt | 41 +++
>>>> drivers/pwm/Kconfig | 9 +
>>>> drivers/pwm/Makefile | 1 +
>>>> drivers/pwm/pwm-atmel.c | 344
>>>> ++++++++++++++++++++
>>>> 4 files changed, 395 insertions(+)
>>>> create mode 100644
>>>> Documentation/devicetree/bindings/pwm/atmel-pwm.txt
>>>> create mode 100644 drivers/pwm/pwm-atmel.c
>>>
>>> I haven't seen an Acked-by from the device tree bindings maintainers on
>>> this. I've Cc'ed them, so hopefully one of them has time to review.
>>
>> Any comments?
>
> As a recommendation from the recent Kernel Summit stated, you will have
> to separate the binding itself from the driver and associated code.
> Simply send the binding documentation to the DT maintainers but still
> keep the two patches linked together in a series (but without putting DT
> maintainers nor the DT mailing-list in CC of the non-documentation
> patches).
>
> This way you may have more chances to get feedback.
Thanks, I will split the binding document as a separate patch.
> Thanks, bye,
Best Regards,
Bo Shen
On 17:10 Mon 30 Sep , Bo Shen wrote:
> Add Atmel PWM controller driver based on PWM framework.
>
> This is the basic function implementation of Atmel PWM controller.
> It can work with PWM based led and backlight.
>
> Signed-off-by: Bo Shen <[email protected]>
>
> ---
> Changes in v5:
> - call clk_disable directly, if so, it won't cause more than one channel
> enabled, the clock can not be disabled.
>
> Changes in v4:
> - check the return value of clk_prepare()
> - change channel register size as constant
>
> Changes in v3:
> - change compatible string from "atmel,sama5-pwm" to "atmel,sama5d3-pwm"
> - Add PWM led example in binding documentation
> - Using micro replace hard code
>
> Changes in v2:
> - Address the comments from Thierry Reding
>
> .../devicetree/bindings/pwm/atmel-pwm.txt | 41 +++
> drivers/pwm/Kconfig | 9 +
> drivers/pwm/Makefile | 1 +
> drivers/pwm/pwm-atmel.c | 344 ++++++++++++++++++++
> 4 files changed, 395 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/pwm/atmel-pwm.txt
> create mode 100644 drivers/pwm/pwm-atmel.c
>
> diff --git a/Documentation/devicetree/bindings/pwm/atmel-pwm.txt b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt
> new file mode 100644
> index 0000000..1c1a5fa
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt
> @@ -0,0 +1,41 @@
> +Atmel PWM controller
> +
> +Required properties:
> + - compatible: should be one of:
> + - "atmel,at91sam9rl-pwm"
> + - "atmel,sama5d3-pwm"
> + - reg: physical base address and length of the controller's registers
> + - #pwm-cells: Should be 3. See pwm.txt in this directory for a
> + description of the cells format
> +
> +Example:
> +
> + pwm0: pwm@f8034000 {
> + compatible = "atmel,at91sam9rl-pwm";
> + reg = <0xf8034000 0x400>;
> + #pwm-cells = <3>;
> + };
> +
> +The following the pwm led based example:
> +
> + pwm0: pwm@f8034000 {
> + compatible = "atmel,at91sam9rl-pwm";
> + reg = <0xf8034000 0x400>;
> + #pwm-cells = <3>;
> + };
> +
> + pwdleds {
> + compatible = "pwm-leds";
> +
> + d1 {
> + label = "d1";
> + pwms = <&pwm0 3 5000 0>
> + max-brightness = <255>;
> + };
> +
> + d2 {
> + label = "d2";
> + pwms = <&pwm0 1 5000 1>
> + max-brightness = <255>;
> + };
> + };
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 75840b5..54237b9 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -41,6 +41,15 @@ config PWM_AB8500
> To compile this driver as a module, choose M here: the module
> will be called pwm-ab8500.
>
> +config PWM_ATMEL
> + tristate "Atmel PWM support"
> + depends on ARCH_AT91
> + help
> + Generic PWM framework driver for Atmel SoC.
> +
> + To compile this driver as a module, choose M here: the module
> + will be called pwm-atmel.
> +
> config PWM_ATMEL_TCB
> tristate "Atmel TC Block PWM support"
> depends on ATMEL_TCLIB && OF
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index 77a8c18..5b193f8 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -1,6 +1,7 @@
> obj-$(CONFIG_PWM) += core.o
> obj-$(CONFIG_PWM_SYSFS) += sysfs.o
> obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o
> +obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o
> obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o
> obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o
> obj-$(CONFIG_PWM_IMX) += pwm-imx.o
> diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
> new file mode 100644
> index 0000000..b4df36c
> --- /dev/null
> +++ b/drivers/pwm/pwm-atmel.c
> @@ -0,0 +1,344 @@
> +/*
> + * Driver for Atmel Pulse Width Modulation Controller
> + *
> + * Copyright (C) 2013 Atmel Corporation
> + * Bo Shen <[email protected]>
> + *
> + * Licensed under GPLv2.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/slab.h>
> +
> +/* The following is global registers for PWM controller */
> +#define PWM_ENA 0x04
> +#define PWM_DIS 0x08
> +#define PWM_SR 0x0C
> +/* bit field in SR */
> +#define PWM_SR_ALL_CH_ON 0x0F
> +
> +/* The following register is PWM channel related registers */
> +#define PWM_CH_REG_OFFSET 0x200
> +#define PWM_CH_REG_SIZE 0x20
> +
> +#define PWM_CMR 0x0
> +/* bit field in CMR */
> +#define PWM_CMR_CPOL (1 << 9)
> +#define PWM_CMR_UPD_CDTY (1 << 10)
> +
> +/* The following registers for PWM v1 */
> +#define PWMv1_CDTY 0x04
> +#define PWMv1_CPRD 0x08
> +#define PWMv1_CUPD 0x10
> +
> +/* The following registers for PWM v2 */
> +#define PWMv2_CDTY 0x04
> +#define PWMv2_CDTYUPD 0x08
> +#define PWMv2_CPRD 0x0C
> +#define PWMv2_CPRDUPD 0x10
no lowercase
> +
> +/* max value for duty and period */
> +/*
> + * Although the duty and period register is 32 bit,
> + * however only the LSB 16 bits are significant.
> + */
> +#define PWM_MAX_DTY 0xFFFF
> +#define PWM_MAX_PRD 0xFFFF
> +#define PRD_MAX_PRES 10
> +
> +struct atmel_pwm_chip {
> + struct pwm_chip chip;
> + struct clk *clk;
> + void __iomem *base;
> +
> + void (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
> + int dty, int prd);
> +};
> +
> +static inline struct atmel_pwm_chip *to_atmel_pwm_chip(struct pwm_chip *chip)
> +{
> + return container_of(chip, struct atmel_pwm_chip, chip);
> +}
> +
> +static inline u32 atmel_pwm_readl(struct atmel_pwm_chip *chip,
> + unsigned long offset)
> +{
> + return readl(chip->base + offset);
use relaxed version
> +}
> +
> +static inline void atmel_pwm_writel(struct atmel_pwm_chip *chip,
> + unsigned long offset, unsigned long val)
> +{
> + writel(val, chip->base + offset);
> +}
> +
> +static inline u32 atmel_pwm_ch_readl(struct atmel_pwm_chip *chip,
> + unsigned int ch, unsigned long offset)
> +{
> + return readl(chip->base + PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE
> + + offset);
> +}
> +
> +static inline void atmel_pwm_ch_writel(struct atmel_pwm_chip *chip,
> + unsigned int ch, unsigned long offset,
> + unsigned long val)
> +{
> + writel(val, chip->base + PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE
> + + offset);
> +}
> +
> +static int atmel_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> + int duty_ns, int period_ns)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> + unsigned long clk_rate, prd, dty;
> + unsigned long long div;
> + int ret, pres = 0;
> +
> + clk_rate = clk_get_rate(atmel_pwm->clk);
> + div = clk_rate;
> +
> + /* Calculate the period cycles */
> + while (div > PWM_MAX_PRD) {
> + div = clk_rate / (1 << pres);
> + div = div * period_ns;
> + /* 1/Hz = 100000000 ns */
> + do_div(div, 1000000000);
> +
> + if (pres++ > PRD_MAX_PRES) {
> + pr_err("PRES is bigger than maximum pre-scaler\n");
> + return -EINVAL;
> + }
> + }
> +
> + /* Calculate the duty cycles */
> + prd = div;
> + div *= duty_ns;
> + do_div(div, period_ns);
> + dty = div;
> +
> + ret = clk_enable(atmel_pwm->clk);
> + if (ret) {
> + pr_err("Failed to enable pwm clock\n");
> + return ret;
> + }
> +
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, pres);
> + atmel_pwm->config(chip, pwm, dty, prd);
> +
> + clk_disable(atmel_pwm->clk);
> +
> + return 0;
> +}
> +
> +static void atmel_pwm_config_v1(struct pwm_chip *chip, struct pwm_device *pwm,
> + int dty, int prd)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> + unsigned int val;
> +
> + /*
> + * If the PWM channel is disabled, write value to duty and period
> + * registers directly.
> + * If the PWM channel is enabled, using the update register, it needs
> + * to set bit 10 of CMR to 0
> + */
> + if (test_bit(PWMF_ENABLED, &pwm->flags)) {
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CUPD, dty);
> +
> + val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR);
> + val &= ~PWM_CMR_UPD_CDTY;
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
> + } else {
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CDTY, dty);
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CPRD, prd);
> + }
> +}
> +
> +static void atmel_pwm_config_v2(struct pwm_chip *chip, struct pwm_device *pwm,
> + int dty, int prd)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> +
> + /*
> + * If the PWM channel is disabled, write value to duty and period
> + * registers directly.
> + * If the PWM channel is enabled, using the duty update register to
> + * update the value.
> + */
> + if (test_bit(PWMF_ENABLED, &pwm->flags)) {
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CDTYUPD, dty);
> + } else {
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CDTY, dty);
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CPRD, prd);
> + }
> +}
> +
> +static int atmel_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
> + enum pwm_polarity polarity)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> + u32 val = 0;
> + int ret;
> +
> + ret = clk_enable(atmel_pwm->clk);
> + if (ret) {
> + pr_err("failed to enable pwm clock\n");
> + return ret;
> + }
> +
> + if (polarity == PWM_POLARITY_NORMAL)
> + val &= ~PWM_CMR_CPOL;
> + else
> + val |= PWM_CMR_CPOL;
> +
clk_enable here
> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
> +
> + clk_disable(atmel_pwm->clk);
> +
> + return 0;
> +}
> +
> +static int atmel_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> + int ret;
> +
> + ret = clk_enable(atmel_pwm->clk);
> + if (ret) {
> + pr_err("failed to enable pwm clock\n");
> + return ret;
> + }
> +
> + atmel_pwm_writel(atmel_pwm, PWM_ENA, 1 << pwm->hwpwm);
> +
> + return 0;
> +}
> +
> +static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
> +
> + atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm);
> +
> + clk_disable(atmel_pwm->clk);
> +}
> +
> +static const struct pwm_ops atmel_pwm_ops = {
> + .config = atmel_pwm_config,
> + .set_polarity = atmel_pwm_set_polarity,
> + .enable = atmel_pwm_enable,
> + .disable = atmel_pwm_disable,
> + .owner = THIS_MODULE,
> +};
> +
> +struct atmel_pwm_data {
> + void (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
> + int dty, int prd);
> +};
what is the point to have one struct for one function pointer?
> +
> +static const struct atmel_pwm_data atmel_pwm_data_v1 = {
> + .config = atmel_pwm_config_v1,
> +};
> +
> +static const struct atmel_pwm_data atmel_pwm_data_v2 = {
> + .config = atmel_pwm_config_v2,
> +};
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id atmel_pwm_dt_ids[] = {
> + {
> + .compatible = "atmel,at91sam9rl-pwm",
> + .data = &atmel_pwm_data_v1,
> + }, {
> + .compatible = "atmel,sama5d3-pwm",
> + .data = &atmel_pwm_data_v2,
> + }, {
> + /* sentinel */
> + },
> +};
> +MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids);
> +#endif
> +
you need to handel both case dt and non-DT
> +static int atmel_pwm_probe(struct platform_device *pdev)
> +{
> + const struct of_device_id *of_id =
> + of_match_device(atmel_pwm_dt_ids, &pdev->dev);
> + const struct atmel_pwm_data *data;
> + struct atmel_pwm_chip *atmel_pwm;
> + struct resource *res;
> + int ret;
> +
> + atmel_pwm = devm_kzalloc(&pdev->dev, sizeof(*atmel_pwm), GFP_KERNEL);
> + if (!atmel_pwm)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res)
> + return -ENODEV;
> +
> + atmel_pwm->base = devm_ioremap_resource(&pdev->dev, res);
you need to check the return
> +
> + atmel_pwm->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(atmel_pwm->clk))
> + return PTR_ERR(atmel_pwm->clk);
> +
> + ret = clk_prepare(atmel_pwm->clk);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to prepare pwm clock\n");
> + return ret;
> + }
> +
> + atmel_pwm->chip.dev = &pdev->dev;
> + atmel_pwm->chip.ops = &atmel_pwm_ops;
> + atmel_pwm->chip.of_xlate = of_pwm_xlate_with_flags;
> + atmel_pwm->chip.of_pwm_n_cells = 3;
> + atmel_pwm->chip.base = -1;
> + atmel_pwm->chip.npwm = 4;
> +
> + data = of_id->data;
> + atmel_pwm->config = data->config;
> +
> + ret = pwmchip_add(&atmel_pwm->chip);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);
> + goto unprepare_clk;
> + }
> +
> + platform_set_drvdata(pdev, atmel_pwm);
> +
> +unprepare_clk:
> + clk_unprepare(atmel_pwm->clk);
> + return ret;
> +}
> +
> +static int atmel_pwm_remove(struct platform_device *pdev)
> +{
> + struct atmel_pwm_chip *atmel_pwm = platform_get_drvdata(pdev);
> +
> + clk_unprepare(atmel_pwm->clk);
> +
> + return pwmchip_remove(&atmel_pwm->chip);
> +}
> +
> +static struct platform_driver atmel_pwm_driver = {
> + .driver = {
> + .name = "atmel-pwm",
> + .of_match_table = of_match_ptr(atmel_pwm_dt_ids),
> + },
> + .probe = atmel_pwm_probe,
> + .remove = atmel_pwm_remove,
> +};
> +module_platform_driver(atmel_pwm_driver);
> +
> +MODULE_ALIAS("platform:atmel-pwm");
> +MODULE_AUTHOR("Bo Shen <[email protected]>");
> +MODULE_DESCRIPTION("Atmel PWM driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.7.9.5
>
Hi J,
On 10/31/2013 13:42, Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 17:10 Mon 30 Sep , Bo Shen wrote:
>> Add Atmel PWM controller driver based on PWM framework.
>>
>> This is the basic function implementation of Atmel PWM controller.
>> It can work with PWM based led and backlight.
>>
>> Signed-off-by: Bo Shen <[email protected]>
>>
>> ---
>> Changes in v5:
>> - call clk_disable directly, if so, it won't cause more than one channel
>> enabled, the clock can not be disabled.
>>
>> Changes in v4:
>> - check the return value of clk_prepare()
>> - change channel register size as constant
>>
>> Changes in v3:
>> - change compatible string from "atmel,sama5-pwm" to "atmel,sama5d3-pwm"
>> - Add PWM led example in binding documentation
>> - Using micro replace hard code
>>
>> Changes in v2:
>> - Address the comments from Thierry Reding
>>
>> .../devicetree/bindings/pwm/atmel-pwm.txt | 41 +++
>> drivers/pwm/Kconfig | 9 +
>> drivers/pwm/Makefile | 1 +
>> drivers/pwm/pwm-atmel.c | 344 ++++++++++++++++++++
>> 4 files changed, 395 insertions(+)
>> create mode 100644
>> Documentation/devicetree/bindings/pwm/atmel-pwm.txt
>> create mode 100644 drivers/pwm/pwm-atmel.c
>>
>> diff --git a/Documentation/devicetree/bindings/pwm/atmel-pwm.txt
>> b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt
>> new file mode 100644
>> index 0000000..1c1a5fa
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt
>> @@ -0,0 +1,41 @@
>> +Atmel PWM controller
>> +
>> +Required properties:
>> + - compatible: should be one of:
>> + - "atmel,at91sam9rl-pwm"
>> + - "atmel,sama5d3-pwm"
>> + - reg: physical base address and length of the controller's
>> +registers
>> + - #pwm-cells: Should be 3. See pwm.txt in this directory for a
>> + description of the cells format
>> +
>> +Example:
>> +
>> + pwm0: pwm@f8034000 {
>> + compatible = "atmel,at91sam9rl-pwm";
>> + reg = <0xf8034000 0x400>;
>> + #pwm-cells = <3>;
>> + };
>> +
>> +The following the pwm led based example:
>> +
>> + pwm0: pwm@f8034000 {
>> + compatible = "atmel,at91sam9rl-pwm";
>> + reg = <0xf8034000 0x400>;
>> + #pwm-cells = <3>;
>> + };
>> +
>> + pwdleds {
>> + compatible = "pwm-leds";
>> +
>> + d1 {
>> + label = "d1";
>> + pwms = <&pwm0 3 5000 0>
>> + max-brightness = <255>;
>> + };
>> +
>> + d2 {
>> + label = "d2";
>> + pwms = <&pwm0 1 5000 1>
>> + max-brightness = <255>;
>> + };
>> + };
>> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index
>> 75840b5..54237b9 100644
>> --- a/drivers/pwm/Kconfig
>> +++ b/drivers/pwm/Kconfig
>> @@ -41,6 +41,15 @@ config PWM_AB8500
>> To compile this driver as a module, choose M here: the module
>> will be called pwm-ab8500.
>>
>> +config PWM_ATMEL
>> + tristate "Atmel PWM support"
>> + depends on ARCH_AT91
>> + help
>> + Generic PWM framework driver for Atmel SoC.
>> +
>> + To compile this driver as a module, choose M here: the module
>> + will be called pwm-atmel.
>> +
>> config PWM_ATMEL_TCB
>> tristate "Atmel TC Block PWM support"
>> depends on ATMEL_TCLIB && OF
>> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index
>> 77a8c18..5b193f8 100644
>> --- a/drivers/pwm/Makefile
>> +++ b/drivers/pwm/Makefile
>> @@ -1,6 +1,7 @@
>> obj-$(CONFIG_PWM) += core.o
>> obj-$(CONFIG_PWM_SYSFS) += sysfs.o
>> obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o
>> +obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o
>> obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o
>> obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o
>> obj-$(CONFIG_PWM_IMX) += pwm-imx.o
>> diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c new
>> file mode 100644 index 0000000..b4df36c
>> --- /dev/null
>> +++ b/drivers/pwm/pwm-atmel.c
>> @@ -0,0 +1,344 @@
>> +/*
>> + * Driver for Atmel Pulse Width Modulation Controller
>> + *
>> + * Copyright (C) 2013 Atmel Corporation
>> + * Bo Shen <[email protected]>
>> + *
>> + * Licensed under GPLv2.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/err.h>
>> +#include <linux/io.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_device.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pwm.h>
>> +#include <linux/slab.h>
>> +
>> +/* The following is global registers for PWM controller */
>> +#define PWM_ENA 0x04
>> +#define PWM_DIS 0x08
>> +#define PWM_SR 0x0C
>> +/* bit field in SR */
>> +#define PWM_SR_ALL_CH_ON 0x0F
>> +
>> +/* The following register is PWM channel related registers */
>> +#define PWM_CH_REG_OFFSET 0x200
>> +#define PWM_CH_REG_SIZE 0x20
>> +
>> +#define PWM_CMR 0x0
>> +/* bit field in CMR */
>> +#define PWM_CMR_CPOL (1 << 9)
>> +#define PWM_CMR_UPD_CDTY (1 << 10)
>> +
>> +/* The following registers for PWM v1 */
>> +#define PWMv1_CDTY 0x04
>> +#define PWMv1_CPRD 0x08
>> +#define PWMv1_CUPD 0x10
>> +
>> +/* The following registers for PWM v2 */
>> +#define PWMv2_CDTY 0x04
>> +#define PWMv2_CDTYUPD 0x08
>> +#define PWMv2_CPRD 0x0C
>> +#define PWMv2_CPRDUPD 0x10
>
> no lowercase
OK, I will change it in v6.
>> +
>> +/* max value for duty and period */
>> +/*
>> + * Although the duty and period register is 32 bit,
>> + * however only the LSB 16 bits are significant.
>> + */
>> +#define PWM_MAX_DTY 0xFFFF
>> +#define PWM_MAX_PRD 0xFFFF
>> +#define PRD_MAX_PRES 10
>> +
>> +struct atmel_pwm_chip {
>> + struct pwm_chip chip;
>> + struct clk *clk;
>> + void __iomem *base;
>> +
>> + void (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
>> + int dty, int prd);
>> +};
>> +
>> +static inline struct atmel_pwm_chip *to_atmel_pwm_chip(struct
>> +pwm_chip *chip) {
>> + return container_of(chip, struct atmel_pwm_chip, chip); }
>> +
>> +static inline u32 atmel_pwm_readl(struct atmel_pwm_chip *chip,
>> + unsigned long offset)
>> +{
>> + return readl(chip->base + offset);
> use relaxed version
OK, I will change in v6.
>> +}
>> +
>> +static inline void atmel_pwm_writel(struct atmel_pwm_chip *chip,
>> + unsigned long offset, unsigned long val) {
>> + writel(val, chip->base + offset);
>> +}
>> +
>> +static inline u32 atmel_pwm_ch_readl(struct atmel_pwm_chip *chip,
>> + unsigned int ch, unsigned long offset) {
>> + return readl(chip->base + PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE
>> + + offset);
>> +}
>> +
>> +static inline void atmel_pwm_ch_writel(struct atmel_pwm_chip *chip,
>> + unsigned int ch, unsigned long offset,
>> + unsigned long val)
>> +{
>> + writel(val, chip->base + PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE
>> + + offset);
>> +}
>> +
>> +static int atmel_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>> + int duty_ns, int period_ns)
>> +{
>> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
>> + unsigned long clk_rate, prd, dty;
>> + unsigned long long div;
>> + int ret, pres = 0;
>> +
>> + clk_rate = clk_get_rate(atmel_pwm->clk);
>> + div = clk_rate;
>> +
>> + /* Calculate the period cycles */
>> + while (div > PWM_MAX_PRD) {
>> + div = clk_rate / (1 << pres);
>> + div = div * period_ns;
>> + /* 1/Hz = 100000000 ns */
>> + do_div(div, 1000000000);
>> +
>> + if (pres++ > PRD_MAX_PRES) {
>> + pr_err("PRES is bigger than maximum pre-scaler\n");
>> + return -EINVAL;
>> + }
>> + }
>> +
>> + /* Calculate the duty cycles */
>> + prd = div;
>> + div *= duty_ns;
>> + do_div(div, period_ns);
>> + dty = div;
>> +
>> + ret = clk_enable(atmel_pwm->clk);
>> + if (ret) {
>> + pr_err("Failed to enable pwm clock\n");
>> + return ret;
>> + }
>> +
>> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, pres);
>> + atmel_pwm->config(chip, pwm, dty, prd);
>> +
>> + clk_disable(atmel_pwm->clk);
>> +
>> + return 0;
>> +}
>> +
>> +static void atmel_pwm_config_v1(struct pwm_chip *chip, struct pwm_device *pwm,
>> + int dty, int prd)
>> +{
>> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
>> + unsigned int val;
>> +
>> + /*
>> + * If the PWM channel is disabled, write value to duty and period
>> + * registers directly.
>> + * If the PWM channel is enabled, using the update register, it needs
>> + * to set bit 10 of CMR to 0
>> + */
>> + if (test_bit(PWMF_ENABLED, &pwm->flags)) {
>> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CUPD, dty);
>> +
>> + val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR);
>> + val &= ~PWM_CMR_UPD_CDTY;
>> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
>> + } else {
>> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CDTY, dty);
>> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv1_CPRD, prd);
>> + }
>> +}
>> +
>> +static void atmel_pwm_config_v2(struct pwm_chip *chip, struct pwm_device *pwm,
>> + int dty, int prd)
>> +{
>> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
>> +
>> + /*
>> + * If the PWM channel is disabled, write value to duty and period
>> + * registers directly.
>> + * If the PWM channel is enabled, using the duty update register to
>> + * update the value.
>> + */
>> + if (test_bit(PWMF_ENABLED, &pwm->flags)) {
>> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CDTYUPD, dty);
>> + } else {
>> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CDTY, dty);
>> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CPRD, prd);
>> + }
>> +}
>> +
>> +static int atmel_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
>> + enum pwm_polarity polarity)
>> +{
>> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
>> + u32 val = 0;
>> + int ret;
>> +
>> + ret = clk_enable(atmel_pwm->clk);
>> + if (ret) {
>> + pr_err("failed to enable pwm clock\n");
>> + return ret;
>> + }
>> +
>> + if (polarity == PWM_POLARITY_NORMAL)
>> + val &= ~PWM_CMR_CPOL;
>> + else
>> + val |= PWM_CMR_CPOL;
>> +
> clk_enable here
OK, I will move clk enable down to here.
>> + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
>> +
>> + clk_disable(atmel_pwm->clk);
>> +
>> + return 0;
>> +}
>> +
>> +static int atmel_pwm_enable(struct pwm_chip *chip, struct pwm_device
>> +*pwm) {
>> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
>> + int ret;
>> +
>> + ret = clk_enable(atmel_pwm->clk);
>> + if (ret) {
>> + pr_err("failed to enable pwm clock\n");
>> + return ret;
>> + }
>> +
>> + atmel_pwm_writel(atmel_pwm, PWM_ENA, 1 << pwm->hwpwm);
>> +
>> + return 0;
>> +}
>> +
>> +static void atmel_pwm_disable(struct pwm_chip *chip, struct
>> +pwm_device *pwm) {
>> + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
>> +
>> + atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm);
>> +
>> + clk_disable(atmel_pwm->clk);
>> +}
>> +
>> +static const struct pwm_ops atmel_pwm_ops = {
>> + .config = atmel_pwm_config,
>> + .set_polarity = atmel_pwm_set_polarity,
>> + .enable = atmel_pwm_enable,
>> + .disable = atmel_pwm_disable,
>> + .owner = THIS_MODULE,
>> +};
>> +
>> +struct atmel_pwm_data {
>> + void (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
>> + int dty, int prd);
>> +};
>
> what is the point to have one struct for one function pointer?
This is just used to pass different configuration fucntion for v1 and
v2. It will be easy to distinguish between v1 and v2.
>> +
>> +static const struct atmel_pwm_data atmel_pwm_data_v1 = {
>> + .config = atmel_pwm_config_v1,
>> +};
>> +
>> +static const struct atmel_pwm_data atmel_pwm_data_v2 = {
>> + .config = atmel_pwm_config_v2,
>> +};
>> +
>> +#ifdef CONFIG_OF
>> +static const struct of_device_id atmel_pwm_dt_ids[] = {
>> + {
>> + .compatible = "atmel,at91sam9rl-pwm",
>> + .data = &atmel_pwm_data_v1,
>> + }, {
>> + .compatible = "atmel,sama5d3-pwm",
>> + .data = &atmel_pwm_data_v2,
>> + }, {
>> + /* sentinel */
>> + },
>> +};
>> +MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids); #endif
>> +
> you need to handel both case dt and non-DT
Ok, I will add for non-DT case.
>> +static int atmel_pwm_probe(struct platform_device *pdev) {
>> + const struct of_device_id *of_id =
>> + of_match_device(atmel_pwm_dt_ids, &pdev->dev);
>> + const struct atmel_pwm_data *data;
>> + struct atmel_pwm_chip *atmel_pwm;
>> + struct resource *res;
>> + int ret;
>> +
>> + atmel_pwm = devm_kzalloc(&pdev->dev, sizeof(*atmel_pwm), GFP_KERNEL);
>> + if (!atmel_pwm)
>> + return -ENOMEM;
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + if (!res)
>> + return -ENODEV;
>> +
>> + atmel_pwm->base = devm_ioremap_resource(&pdev->dev, res);
> you need to check the return
OK, I will add it in v6.
>> +
>> + atmel_pwm->clk = devm_clk_get(&pdev->dev, NULL);
>> + if (IS_ERR(atmel_pwm->clk))
>> + return PTR_ERR(atmel_pwm->clk);
>> +
>> + ret = clk_prepare(atmel_pwm->clk);
>> + if (ret) {
>> + dev_err(&pdev->dev, "failed to prepare pwm clock\n");
>> + return ret;
>> + }
>> +
>> + atmel_pwm->chip.dev = &pdev->dev;
>> + atmel_pwm->chip.ops = &atmel_pwm_ops;
>> + atmel_pwm->chip.of_xlate = of_pwm_xlate_with_flags;
>> + atmel_pwm->chip.of_pwm_n_cells = 3;
>> + atmel_pwm->chip.base = -1;
>> + atmel_pwm->chip.npwm = 4;
>> +
>> + data = of_id->data;
>> + atmel_pwm->config = data->config;
>> +
>> + ret = pwmchip_add(&atmel_pwm->chip);
>> + if (ret < 0) {
>> + dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);
>> + goto unprepare_clk;
>> + }
>> +
>> + platform_set_drvdata(pdev, atmel_pwm);
>> +
>> +unprepare_clk:
>> + clk_unprepare(atmel_pwm->clk);
>> + return ret;
>> +}
>> +
>> +static int atmel_pwm_remove(struct platform_device *pdev) {
>> + struct atmel_pwm_chip *atmel_pwm = platform_get_drvdata(pdev);
>> +
>> + clk_unprepare(atmel_pwm->clk);
>> +
>> + return pwmchip_remove(&atmel_pwm->chip); }
>> +
>> +static struct platform_driver atmel_pwm_driver = {
>> + .driver = {
>> + .name = "atmel-pwm",
>> + .of_match_table = of_match_ptr(atmel_pwm_dt_ids),
>> + },
>> + .probe = atmel_pwm_probe,
>> + .remove = atmel_pwm_remove,
>> +};
>> +module_platform_driver(atmel_pwm_driver);
>> +
>> +MODULE_ALIAS("platform:atmel-pwm");
>> +MODULE_AUTHOR("Bo Shen <[email protected]>");
>> +MODULE_DESCRIPTION("Atmel PWM driver"); MODULE_LICENSE("GPL v2");
>> --
>> 1.7.9.5
>>
Best Regards,
Bo Shen