* [PATCH v4 0/2] PWM support for HiFive Unleashed
@ 2019-01-21 10:20 Yash Shah
2019-01-21 10:20 ` [PATCH v4 1/2] pwm: sifive: Add DT documentation for SiFive PWM Controller Yash Shah
2019-01-21 10:20 ` [PATCH v4 2/2] pwm: sifive: Add a driver for SiFive SoC PWM Yash Shah
0 siblings, 2 replies; 5+ messages in thread
From: Yash Shah @ 2019-01-21 10:20 UTC (permalink / raw)
To: palmer, linux-pwm, linux-riscv
Cc: thierry.reding, robh+dt, mark.rutland, devicetree, linux-kernel,
sachin.ghadi, paul.walmsley, Yash Shah
This patch series adds a PWM driver and DT documentation
for HiFive Unleashed board. The patches are mostly based on
Wesley's patch.
v4
- Rename the property sifive,approx-period-ns to sifive,period-ns
- Rename macros with appropriate names
- Remove unused macros
- Rename struct sifive_pwm_device to struct pwm_sifive_ddata
- Rename function prefix as per driver name
- Set deglitch bit before changing output waveform.
- Other minor fixes based upon feedback on v3
v3
- Add a link to the reference manaul
- Use appropriate apis for division operation
- Add check for polarity
- Enable clk before calling clk_get_rate
- Other minor fixes based upon feedback on v2
V2 changed from V1:
- Remove inclusion of dt-bindings/pwm/pwm.h
- Remove artificial alignments
- Replace ioread32/iowrite32 with readl/writel
- Remove camelcase
- Change dev_info to dev_dbg for unnecessary log
- Correct typo in driver name
- Remove use of of_match_ptr macro
- Update the DT compatible strings and Add reference to a common
versioning document
Yash Shah (2):
pwm: sifive: Add DT documentation for SiFive PWM Controller
pwm: sifive: Add a driver for SiFive SoC PWM
.../devicetree/bindings/pwm/pwm-sifive.txt | 37 +++
drivers/pwm/Kconfig | 11 +
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-sifive.c | 262 +++++++++++++++++++++
4 files changed, 311 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pwm/pwm-sifive.txt
create mode 100644 drivers/pwm/pwm-sifive.c
--
1.9.1
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v4 1/2] pwm: sifive: Add DT documentation for SiFive PWM Controller
2019-01-21 10:20 [PATCH v4 0/2] PWM support for HiFive Unleashed Yash Shah
@ 2019-01-21 10:20 ` Yash Shah
2019-01-21 14:59 ` Rob Herring
2019-01-21 10:20 ` [PATCH v4 2/2] pwm: sifive: Add a driver for SiFive SoC PWM Yash Shah
1 sibling, 1 reply; 5+ messages in thread
From: Yash Shah @ 2019-01-21 10:20 UTC (permalink / raw)
To: palmer, linux-pwm, linux-riscv
Cc: thierry.reding, robh+dt, mark.rutland, devicetree, linux-kernel,
sachin.ghadi, paul.walmsley, Yash Shah
DT documentation for PWM controller added.
Signed-off-by: Wesley W. Terpstra <wesley@sifive.com>
[Atish: Compatible string update]
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Yash Shah <yash.shah@sifive.com>
---
.../devicetree/bindings/pwm/pwm-sifive.txt | 37 ++++++++++++++++++++++
1 file changed, 37 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pwm/pwm-sifive.txt
diff --git a/Documentation/devicetree/bindings/pwm/pwm-sifive.txt b/Documentation/devicetree/bindings/pwm/pwm-sifive.txt
new file mode 100644
index 0000000..b207908
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/pwm-sifive.txt
@@ -0,0 +1,37 @@
+SiFive PWM controller
+
+Unlike most other PWM controllers, the SiFive PWM controller currently only
+supports one period for all channels in the PWM. This is set globally in DTS.
+The period also has significant restrictions on the values it can achieve,
+which the driver rounds to the nearest achievable frequency.
+
+Required properties:
+- compatible: Should be "sifive,pwmX" and "sifive,$socname-pwm".
+ Please refer to sifive-blocks-ip-versioning.txt for details.
+- reg: physical base address and length of the controller's registers
+- clocks: Should contain a clock identifier for the PWM's parent clock.
+- #pwm-cells: Should be 2.
+ Refer to bindings/pwm/pwm.txt for details.
+- sifive,period-ns: the driver will get as close to this period as it can
+- interrupts: one interrupt per PWM channel
+
+PWM RTL that corresponds to the IP block version numbers can be found
+here:
+
+https://github.com/sifive/sifive-blocks/tree/master/src/main/scala/devices/pwm
+
+Further information on the format of the IP
+block-specific version numbers can be found in
+Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
+
+Examples:
+
+pwm: pwm@10020000 {
+ compatible = "sifive,fu540-c000-pwm","sifive,pwm0";
+ reg = <0x0 0x10020000 0x0 0x1000>;
+ clocks = <&tlclk>;
+ interrupt-parent = <&plic>;
+ interrupts = <42 43 44 45>;
+ #pwm-cells = <2>;
+ sifive,period-ns = <1000000>;
+};
--
1.9.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v4 2/2] pwm: sifive: Add a driver for SiFive SoC PWM
2019-01-21 10:20 [PATCH v4 0/2] PWM support for HiFive Unleashed Yash Shah
2019-01-21 10:20 ` [PATCH v4 1/2] pwm: sifive: Add DT documentation for SiFive PWM Controller Yash Shah
@ 2019-01-21 10:20 ` Yash Shah
1 sibling, 0 replies; 5+ messages in thread
From: Yash Shah @ 2019-01-21 10:20 UTC (permalink / raw)
To: palmer, linux-pwm, linux-riscv
Cc: thierry.reding, robh+dt, mark.rutland, devicetree, linux-kernel,
sachin.ghadi, paul.walmsley, Yash Shah
Adds a PWM driver for PWM chip present in SiFive's HiFive Unleashed SoC.
Signed-off-by: Wesley W. Terpstra <wesley@sifive.com>
[Atish: Various fixes and code cleanup]
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Yash Shah <yash.shah@sifive.com>
---
drivers/pwm/Kconfig | 11 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-sifive.c | 262 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 274 insertions(+)
create mode 100644 drivers/pwm/pwm-sifive.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index a8f47df..4a61d1a 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -380,6 +380,17 @@ config PWM_SAMSUNG
To compile this driver as a module, choose M here: the module
will be called pwm-samsung.
+config PWM_SIFIVE
+ tristate "SiFive PWM support"
+ depends on OF
+ depends on COMMON_CLK
+ depends on RISCV || COMPILE_TEST
+ help
+ Generic PWM framework driver for SiFive SoCs.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-sifive.
+
config PWM_SPEAR
tristate "STMicroelectronics SPEAr PWM support"
depends on PLAT_SPEAR
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 9c676a0..30089ca 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_PWM_RCAR) += pwm-rcar.o
obj-$(CONFIG_PWM_RENESAS_TPU) += pwm-renesas-tpu.o
obj-$(CONFIG_PWM_ROCKCHIP) += pwm-rockchip.o
obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
+obj-$(CONFIG_PWM_SIFIVE) += pwm-sifive.o
obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o
obj-$(CONFIG_PWM_STI) += pwm-sti.o
obj-$(CONFIG_PWM_STM32) += pwm-stm32.o
diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c
new file mode 100644
index 0000000..bbc4ae8
--- /dev/null
+++ b/drivers/pwm/pwm-sifive.c
@@ -0,0 +1,262 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2017-2018 SiFive
+ * For SiFive's PWM IP block documentation please refer Chapter 14 of
+ * Reference Manual : https://static.dev.sifive.com/FU540-C000-v1.0.pdf
+ */
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+/* Register offsets */
+#define PWM_SIFIVE_PWMCFG 0x0
+#define PWM_SIFIVE_PWMCOUNT 0x8
+#define PWM_SIFIVE_PWMS 0x10
+#define PWM_SIFIVE_PWMCMP0 0x20
+
+/* PWMCFG fields */
+#define PWM_SIFIVE_PWMCFG_SCALE 0
+#define PWM_SIFIVE_PWMCFG_STICKY 8
+#define PWM_SIFIVE_PWMCFG_ZERO_CMP 9
+#define PWM_SIFIVE_PWMCFG_DEGLITCH 10
+#define PWM_SIFIVE_PWMCFG_EN_ALWAYS 12
+#define PWM_SIFIVE_PWMCFG_EN_ONCE 13
+#define PWM_SIFIVE_PWMCFG_CENTER 16
+#define PWM_SIFIVE_PWMCFG_GANG 24
+#define PWM_SIFIVE_PWMCFG_IP 28
+
+/* SIZE_PWMCMP is used to calculate the offset for pwmcmpX registers */
+#define SIZE_PWMCMP 4
+#define CMPWIDTH 16
+
+struct pwm_sifive_ddata {
+ struct pwm_chip chip;
+ struct notifier_block notifier;
+ struct clk *clk;
+ void __iomem *regs;
+ unsigned int approx_period;
+ unsigned int real_period;
+};
+
+static inline struct pwm_sifive_ddata *to_pwm_sifive_chip(struct pwm_chip *c)
+{
+ return container_of(c, struct pwm_sifive_ddata, chip);
+}
+
+static void pwm_sifive_get_state(struct pwm_chip *chip, struct pwm_device *dev,
+ struct pwm_state *state)
+{
+ struct pwm_sifive_ddata *pwm = to_pwm_sifive_chip(chip);
+ u32 duty;
+
+ duty = readl(pwm->regs + PWM_SIFIVE_PWMCMP0 + dev->hwpwm * SIZE_PWMCMP);
+
+ state->period = pwm->real_period;
+ state->duty_cycle = ((u64)duty * pwm->real_period) >> CMPWIDTH;
+ state->polarity = PWM_POLARITY_INVERSED;
+ state->enabled = duty > 0;
+}
+
+static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *dev,
+ struct pwm_state *state)
+{
+ struct pwm_sifive_ddata *pwm = to_pwm_sifive_chip(chip);
+ unsigned int duty_cycle;
+ u32 frac, val;
+
+ if (state->polarity != PWM_POLARITY_INVERSED)
+ return -EINVAL;
+
+ if (state->period != pwm->real_period)
+ return -EINVAL;
+
+ duty_cycle = state->duty_cycle;
+ if (!state->enabled)
+ duty_cycle = 0;
+
+ frac = div_u64((u64)duty_cycle * 0xFFFF, state->period);
+ frac = min(frac, 0xFFFFU);
+
+ val = readl(pwm->regs + PWM_SIFIVE_PWMCFG);
+ val |= (1 << PWM_SIFIVE_PWMCFG_DEGLITCH);
+ writel(val, pwm->regs + PWM_SIFIVE_PWMCFG);
+
+ writel(frac, pwm->regs + PWM_SIFIVE_PWMCMP0 + dev->hwpwm * SIZE_PWMCMP);
+
+ val &= ~(1 << PWM_SIFIVE_PWMCFG_DEGLITCH);
+ writel(val, pwm->regs + PWM_SIFIVE_PWMCFG);
+
+ if (state->enabled)
+ pwm_sifive_get_state(chip, dev, state);
+
+ return 0;
+}
+
+static const struct pwm_ops pwm_sifive_ops = {
+ .get_state = pwm_sifive_get_state,
+ .apply = pwm_sifive_apply,
+ .owner = THIS_MODULE,
+};
+
+static struct pwm_device *pwm_sifive_xlate(struct pwm_chip *chip,
+ const struct of_phandle_args *args)
+{
+ struct pwm_sifive_ddata *pwm = to_pwm_sifive_chip(chip);
+ struct pwm_device *dev;
+
+ if (args->args[0] >= chip->npwm)
+ return ERR_PTR(-EINVAL);
+
+ dev = pwm_request_from_chip(chip, args->args[0], NULL);
+ if (IS_ERR(dev))
+ return dev;
+
+ /* The period cannot be changed on a per-PWM basis */
+ dev->args.period = pwm->real_period;
+ dev->args.polarity = PWM_POLARITY_NORMAL;
+ if (args->args[1] & PWM_POLARITY_INVERSED)
+ dev->args.polarity = PWM_POLARITY_INVERSED;
+
+ return dev;
+}
+
+static void pwm_sifive_update_clock(struct pwm_sifive_ddata *pwm,
+ unsigned long rate)
+{
+ /* (1 << (16+scale)) * 10^9/rate = real_period */
+ unsigned long scale_pow =
+ (pwm->approx_period * (u64)rate) / NSEC_PER_SEC;
+ int scale = clamp(ilog2(scale_pow) - 16, 0, 0xf);
+
+ writel((1 << PWM_SIFIVE_PWMCFG_EN_ALWAYS) | (scale <<
+ PWM_SIFIVE_PWMCFG_SCALE), pwm->regs + PWM_SIFIVE_PWMCFG);
+
+ /* As scale <= 15 the shift operation cannot overflow. */
+ pwm->real_period = div64_ul(1000000000ULL << (16 + scale), rate);
+ dev_dbg(pwm->chip.dev, "New real_period = %u ns\n", pwm->real_period);
+}
+
+static int pwm_sifive_clock_notifier(struct notifier_block *nb,
+ unsigned long event, void *data)
+{
+ struct clk_notifier_data *ndata = data;
+ struct pwm_sifive_ddata *pwm =
+ container_of(nb, struct pwm_sifive_ddata, notifier);
+
+ if (event == POST_RATE_CHANGE)
+ pwm_sifive_update_clock(pwm, ndata->new_rate);
+
+ return NOTIFY_OK;
+}
+
+static int pwm_sifive_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *node = pdev->dev.of_node;
+ struct pwm_sifive_ddata *pwm;
+ struct pwm_chip *chip;
+ struct resource *res;
+ int ret;
+
+ pwm = devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL);
+ if (!pwm)
+ return -ENOMEM;
+
+ chip = &pwm->chip;
+ chip->dev = dev;
+ chip->ops = &pwm_sifive_ops;
+ chip->of_xlate = pwm_sifive_xlate;
+ chip->of_pwm_n_cells = 2;
+ chip->base = -1;
+ chip->npwm = 4;
+
+ ret = of_property_read_u32(node, "sifive,period-ns",
+ &pwm->approx_period);
+
+ if (ret < 0) {
+ dev_err(dev, "Unable to read sifive,period-ns from DTS\n");
+ return ret;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ pwm->regs = devm_ioremap_resource(dev, res);
+ if (IS_ERR(pwm->regs)) {
+ dev_err(dev, "Unable to map IO resources\n");
+ return PTR_ERR(pwm->regs);
+ }
+
+ pwm->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(pwm->clk)) {
+ if (PTR_ERR(pwm->clk) != -EPROBE_DEFER)
+ dev_err(dev, "Unable to find controller clock\n");
+ return PTR_ERR(pwm->clk);
+ }
+
+ ret = clk_prepare_enable(pwm->clk);
+ if (ret) {
+ dev_err(dev, "failed to enable clock for pwm: %d\n", ret);
+ return ret;
+ }
+
+ /* Watch for changes to underlying clock frequency */
+ pwm->notifier.notifier_call = pwm_sifive_clock_notifier;
+ ret = clk_notifier_register(pwm->clk, &pwm->notifier);
+ if (ret) {
+ dev_err(dev, "failed to register clock notifier: %d\n", ret);
+ goto disable_clk;
+ }
+
+ /* Initialize PWM config */
+ pwm_sifive_update_clock(pwm, clk_get_rate(pwm->clk));
+
+ ret = pwmchip_add(chip);
+ if (ret < 0) {
+ dev_err(dev, "cannot register PWM: %d\n", ret);
+ goto unregister_clk;
+ }
+
+ platform_set_drvdata(pdev, pwm);
+ dev_dbg(dev, "SiFive PWM chip registered %d PWMs\n", chip->npwm);
+
+ return 0;
+
+unregister_clk:
+ clk_notifier_unregister(pwm->clk, &pwm->notifier);
+disable_clk:
+ clk_disable_unprepare(pwm->clk);
+
+ return ret;
+}
+
+static int pwm_sifive_remove(struct platform_device *dev)
+{
+ struct pwm_sifive_ddata *pwm = platform_get_drvdata(dev);
+ int ret;
+
+ ret = pwmchip_remove(&pwm->chip);
+ clk_notifier_unregister(pwm->clk, &pwm->notifier);
+ clk_disable_unprepare(pwm->clk);
+ return ret;
+}
+
+static const struct of_device_id pwm_sifive_of_match[] = {
+ { .compatible = "sifive,pwm0" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, pwm_sifive_of_match);
+
+static struct platform_driver pwm_sifive_driver = {
+ .probe = pwm_sifive_probe,
+ .remove = pwm_sifive_remove,
+ .driver = {
+ .name = "pwm-sifive",
+ .of_match_table = pwm_sifive_of_match,
+ },
+};
+module_platform_driver(pwm_sifive_driver);
+
+MODULE_DESCRIPTION("SiFive PWM driver");
+MODULE_LICENSE("GPL v2");
--
1.9.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v4 1/2] pwm: sifive: Add DT documentation for SiFive PWM Controller
2019-01-21 10:20 ` [PATCH v4 1/2] pwm: sifive: Add DT documentation for SiFive PWM Controller Yash Shah
@ 2019-01-21 14:59 ` Rob Herring
2019-01-24 8:58 ` Yash Shah
0 siblings, 1 reply; 5+ messages in thread
From: Rob Herring @ 2019-01-21 14:59 UTC (permalink / raw)
To: Yash Shah
Cc: palmer, linux-pwm, linux-riscv, thierry.reding, mark.rutland,
devicetree, linux-kernel, sachin.ghadi, paul.walmsley
On Mon, Jan 21, 2019 at 03:50:42PM +0530, Yash Shah wrote:
> DT documentation for PWM controller added.
>
> Signed-off-by: Wesley W. Terpstra <wesley@sifive.com>
> [Atish: Compatible string update]
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Signed-off-by: Yash Shah <yash.shah@sifive.com>
> ---
> .../devicetree/bindings/pwm/pwm-sifive.txt | 37 ++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/pwm/pwm-sifive.txt
>
> diff --git a/Documentation/devicetree/bindings/pwm/pwm-sifive.txt b/Documentation/devicetree/bindings/pwm/pwm-sifive.txt
> new file mode 100644
> index 0000000..b207908
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/pwm-sifive.txt
> @@ -0,0 +1,37 @@
> +SiFive PWM controller
> +
> +Unlike most other PWM controllers, the SiFive PWM controller currently only
> +supports one period for all channels in the PWM. This is set globally in DTS.
> +The period also has significant restrictions on the values it can achieve,
> +which the driver rounds to the nearest achievable frequency.
> +
> +Required properties:
> +- compatible: Should be "sifive,pwmX" and "sifive,$socname-pwm".
The order here is wrong.
You still need to enumeration valid version numbers. Is 'sifive,pwm20'
valid?
> + Please refer to sifive-blocks-ip-versioning.txt for details.
> +- reg: physical base address and length of the controller's registers
> +- clocks: Should contain a clock identifier for the PWM's parent clock.
> +- #pwm-cells: Should be 2.
> + Refer to bindings/pwm/pwm.txt for details.
> +- sifive,period-ns: the driver will get as close to this period as it can
> +- interrupts: one interrupt per PWM channel
How many channels? If variable, is the a max number?
> +
> +PWM RTL that corresponds to the IP block version numbers can be found
> +here:
> +
> +https://github.com/sifive/sifive-blocks/tree/master/src/main/scala/devices/pwm
Put this in the description at the top.
> +
> +Further information on the format of the IP
> +block-specific version numbers can be found in
> +Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
You already said this.
> +
> +Examples:
> +
> +pwm: pwm@10020000 {
> + compatible = "sifive,fu540-c000-pwm","sifive,pwm0";
Space after the ',' needed.
> + reg = <0x0 0x10020000 0x0 0x1000>;
> + clocks = <&tlclk>;
> + interrupt-parent = <&plic>;
> + interrupts = <42 43 44 45>;
> + #pwm-cells = <2>;
> + sifive,period-ns = <1000000>;
> +};
> --
> 1.9.1
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v4 1/2] pwm: sifive: Add DT documentation for SiFive PWM Controller
2019-01-21 14:59 ` Rob Herring
@ 2019-01-24 8:58 ` Yash Shah
0 siblings, 0 replies; 5+ messages in thread
From: Yash Shah @ 2019-01-24 8:58 UTC (permalink / raw)
To: Rob Herring
Cc: Palmer Dabbelt, linux-pwm, linux-riscv, Thierry Reding,
mark.rutland, devicetree, linux-kernel, Sachin Ghadi,
Paul Walmsley
On Mon, Jan 21, 2019 at 8:29 PM Rob Herring <robh@kernel.org> wrote:
>
> On Mon, Jan 21, 2019 at 03:50:42PM +0530, Yash Shah wrote:
> > DT documentation for PWM controller added.
> >
> > Signed-off-by: Wesley W. Terpstra <wesley@sifive.com>
> > [Atish: Compatible string update]
> > Signed-off-by: Atish Patra <atish.patra@wdc.com>
> > Signed-off-by: Yash Shah <yash.shah@sifive.com>
> > ---
> > .../devicetree/bindings/pwm/pwm-sifive.txt | 37 ++++++++++++++++++++++
> > 1 file changed, 37 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/pwm/pwm-sifive.txt
> >
> > diff --git a/Documentation/devicetree/bindings/pwm/pwm-sifive.txt b/Documentation/devicetree/bindings/pwm/pwm-sifive.txt
> > new file mode 100644
> > index 0000000..b207908
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/pwm/pwm-sifive.txt
> > @@ -0,0 +1,37 @@
> > +SiFive PWM controller
> > +
> > +Unlike most other PWM controllers, the SiFive PWM controller currently only
> > +supports one period for all channels in the PWM. This is set globally in DTS.
> > +The period also has significant restrictions on the values it can achieve,
> > +which the driver rounds to the nearest achievable frequency.
> > +
> > +Required properties:
> > +- compatible: Should be "sifive,pwmX" and "sifive,$socname-pwm".
>
> The order here is wrong.
Will fix the order.
>
> You still need to enumeration valid version numbers. Is 'sifive,pwm20'
> valid?
Yes
>
> > + Please refer to sifive-blocks-ip-versioning.txt for details.
> > +- reg: physical base address and length of the controller's registers
> > +- clocks: Should contain a clock identifier for the PWM's parent clock.
> > +- #pwm-cells: Should be 2.
> > + Refer to bindings/pwm/pwm.txt for details.
> > +- sifive,period-ns: the driver will get as close to this period as it can
> > +- interrupts: one interrupt per PWM channel
>
> How many channels? If variable, is the a max number?
Max 4 channels.
>
> > +
> > +PWM RTL that corresponds to the IP block version numbers can be found
> > +here:
> > +
> > +https://github.com/sifive/sifive-blocks/tree/master/src/main/scala/devices/pwm
>
> Put this in the description at the top.
Sure.
>
> > +
> > +Further information on the format of the IP
> > +block-specific version numbers can be found in
> > +Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
>
> You already said this.
Will remove redundant info.
>
> > +
> > +Examples:
> > +
> > +pwm: pwm@10020000 {
> > + compatible = "sifive,fu540-c000-pwm","sifive,pwm0";
>
> Space after the ',' needed.
Sure
>
> > + reg = <0x0 0x10020000 0x0 0x1000>;
> > + clocks = <&tlclk>;
> > + interrupt-parent = <&plic>;
> > + interrupts = <42 43 44 45>;
> > + #pwm-cells = <2>;
> > + sifive,period-ns = <1000000>;
> > +};
> > --
> > 1.9.1
> >
Thanks for the feedback
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2019-01-24 8:59 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-01-21 10:20 [PATCH v4 0/2] PWM support for HiFive Unleashed Yash Shah
2019-01-21 10:20 ` [PATCH v4 1/2] pwm: sifive: Add DT documentation for SiFive PWM Controller Yash Shah
2019-01-21 14:59 ` Rob Herring
2019-01-24 8:58 ` Yash Shah
2019-01-21 10:20 ` [PATCH v4 2/2] pwm: sifive: Add a driver for SiFive SoC PWM Yash Shah
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).