The Sophgo CV1800 chip provides a set of four independent
PWM channel outputs.
This series adds PWM controller support for Sophgo cv1800.
Changes since v3:
- use macro instead of npwm number
- add support for polarity feature
- add Output-Enable/OE check
v3: https://lore.kernel.org/all/[email protected]/
Changes since v2:
- use 0x08 instead of macro
- split if statements based on conditions
- in order to round up, first calculate the
number of high-level cycles, then subtract
it from the PERIOD to obtain the number of HLPERIOD
- use new pwmchip_alloc() API instead of old style
v2: https://lore.kernel.org/all/[email protected]/
Changes since v1:
- drop full stop from subject
- re-order maintainers and description
- pass checkpatch.pl --strict
- fix naming errors
- add "Limitations" section
- use a driver specific prefix for all defines
- using bool instead u32 in cv1800_pwm_enable
- check and set state->polarity
- use mul_u64_u64_div_u64
- use clk_rate_exclusive_get(), balance with clk_rate_exclusive_put()
- using macro definitions instead of shift operations
- remove shift operation on 0
- use priv replace cv_pwm
- hardcode npwm
- set atomic to true
- remove MODULE_ALIAS
v1: https://lore.kernel.org/all/[email protected]/
Jingbao Qiu (2):
dt-bindings: pwm: sophgo: add pwm for Sophgo CV1800 series SoC
pwm: sophgo: add pwm support for Sophgo CV1800 SoC
.../bindings/pwm/sophgo,cv1800-pwm.yaml | 45 +++
drivers/pwm/Kconfig | 10 +
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-cv1800.c | 314 ++++++++++++++++++
4 files changed, 370 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pwm/sophgo,cv1800-pwm.yaml
create mode 100644 drivers/pwm/pwm-cv1800.c
base-commit: 801de0882d8a95aa1b1fe67df1696e037d785656
--
2.25.1
Add devicetree binding to describe the PWM for Sophgo CV1800 SoC.
Reviewed-by: Krzysztof Kozlowski <[email protected]>
Signed-off-by: Jingbao Qiu <[email protected]>
---
.../bindings/pwm/sophgo,cv1800-pwm.yaml | 45 +++++++++++++++++++
1 file changed, 45 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pwm/sophgo,cv1800-pwm.yaml
diff --git a/Documentation/devicetree/bindings/pwm/sophgo,cv1800-pwm.yaml b/Documentation/devicetree/bindings/pwm/sophgo,cv1800-pwm.yaml
new file mode 100644
index 000000000000..b5b819d780f1
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/sophgo,cv1800-pwm.yaml
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/sophgo,cv1800-pwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sophgo CV1800 PWM controller
+
+maintainers:
+ - Jingbao Qiu <[email protected]>
+
+description:
+ The chip provides a set of four independent PWM channel outputs.
+
+allOf:
+ - $ref: pwm.yaml#
+
+properties:
+ compatible:
+ const: sophgo,cv1800-pwm
+
+ reg:
+ maxItems: 1
+
+ clocks:
+ maxItems: 1
+
+ "#pwm-cells":
+ const: 3
+
+required:
+ - compatible
+ - reg
+ - clocks
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ pwm0: pwm@3060000 {
+ compatible = "sophgo,cv1800-pwm";
+ reg = <0x3060000 0x1000>;
+ clocks = <&clk 60>;
+ #pwm-cells = <3>;
+ };
--
2.25.1
Implement the PWM driver for CV1800.
Signed-off-by: Jingbao Qiu <[email protected]>
---
drivers/pwm/Kconfig | 10 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-cv1800.c | 314 +++++++++++++++++++++++++++++++++++++++
3 files changed, 325 insertions(+)
create mode 100644 drivers/pwm/pwm-cv1800.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 4b956d661755..455f07af94f7 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -186,6 +186,16 @@ config PWM_CROS_EC
PWM driver for exposing a PWM attached to the ChromeOS Embedded
Controller.
+config PWM_CV1800
+ tristate "Sophgo CV1800 PWM driver"
+ depends on ARCH_SOPHGO || COMPILE_TEST
+ help
+ Generic PWM framework driver for the Sophgo CV1800 series
+ SoCs.
+
+ To compile this driver as a module, build the dependecies
+ as modules, this will be called pwm-cv1800.
+
config PWM_DWC_CORE
tristate
depends on HAS_IOMEM
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index c5ec9e168ee7..6c3c4a07a316 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_PWM_CLK) += pwm-clk.o
obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o
obj-$(CONFIG_PWM_CRC) += pwm-crc.o
obj-$(CONFIG_PWM_CROS_EC) += pwm-cros-ec.o
+obj-$(CONFIG_PWM_CV1800) += pwm-cv1800.o
obj-$(CONFIG_PWM_DWC_CORE) += pwm-dwc-core.o
obj-$(CONFIG_PWM_DWC) += pwm-dwc.o
obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o
diff --git a/drivers/pwm/pwm-cv1800.c b/drivers/pwm/pwm-cv1800.c
new file mode 100644
index 000000000000..d5b31a2b7787
--- /dev/null
+++ b/drivers/pwm/pwm-cv1800.c
@@ -0,0 +1,314 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * pwm-cv1800.c: PWM driver for Sophgo cv1800
+ *
+ * Author: Jingbao Qiu <[email protected]>
+ *
+ * Limitations:
+ * - It output low when PWM channel disabled.
+ * - This pwm device supports dynamic loading of PWM parameters. When PWMSTART
+ * is written from 0 to 1, the register value (HLPERIODn, PERIODn) will be
+ * temporarily stored inside the PWM. If you want to dynamically change the
+ * waveform during PWM output, after writing the new value to HLPERIODn and
+ * PERIODn, write 1 and then 0 to PWMUPDATE[n] to make the new value effective.
+ * - Supports up to Rate/2 output, and the lowest is about Rate/(2^30-1).
+ * - By setting HLPERIODn to 0, can produce 100% duty cycle.
+ * - This hardware could support inverted polarity. By default, the value of the
+ * POLARITY register is 0x0. This means that HLPERIOD represents the number
+ * of low level beats.
+ * - This hardware supports input mode and output mode, implemented through the
+ * Output-Enable/OE register. However, this driver has not yet implemented
+ * capture callback.
+ */
+
+#include <linux/clk.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/regmap.h>
+
+#define PWM_CV1800_HLPERIOD_BASE 0x00
+#define PWM_CV1800_PERIOD_BASE 0x04
+#define PWM_CV1800_POLARITY 0x40
+#define PWM_CV1800_START 0x44
+#define PWM_CV1800_DONE 0x48
+#define PWM_CV1800_UPDATE 0x4c
+#define PWM_CV1800_OE 0xd0
+
+#define PWM_CV1800_HLPERIOD(n) (PWM_CV1800_HLPERIOD_BASE + ((n) * 0x08))
+#define PWM_CV1800_PERIOD(n) (PWM_CV1800_PERIOD_BASE + ((n) * 0x08))
+
+#define PWM_CV1800_UPDATE_MASK(n) (BIT(0) << (n))
+#define PWM_CV1800_OE_MASK(n) (BIT(0) << (n))
+#define PWM_CV1800_START_MASK(n) (BIT(0) << (n))
+#define PWM_CV1800_POLARITY_MASK(n) (BIT(0) << (n))
+
+#define PWM_CV1800_OE_INPUT 0x00U
+#define PWM_CV1800_OE_OUTPUT(n) (BIT(0) << (n))
+#define PWM_CV1800_MAXPERIOD (BIT(30) - 1)
+#define PWM_CV1800_MINPERIOD BIT(1)
+#define PWM_CV1800_PERIOD_RESET BIT(1)
+#define PWM_CV1800_HLPERIOD_RESET BIT(0)
+#define PWM_CV1800_REG_DISABLE 0x00U
+#define PWM_CV1800_REG_ENABLE(n) (BIT(0) << (n))
+#define PWM_CV1800_CHANNELS 4
+
+struct cv1800_pwm {
+ struct regmap *map;
+ struct clk *clk;
+ unsigned long clk_rate;
+};
+
+static inline struct cv1800_pwm *to_cv1800_pwm_dev(struct pwm_chip *chip)
+{
+ return pwmchip_get_drvdata(chip);
+}
+
+static const struct regmap_config cv1800_pwm_regmap_config = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+};
+
+static int cv1800_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm,
+ bool enable)
+{
+ struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
+ u32 pwm_enable;
+
+ regmap_read(priv->map, PWM_CV1800_START, &pwm_enable);
+ pwm_enable &= PWM_CV1800_START_MASK(pwm->hwpwm);
+
+ /*
+ * If the parameters are changed during runtime, Register needs
+ * to be updated to take effect.
+ */
+ if (pwm_enable && enable) {
+ regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
+ PWM_CV1800_UPDATE_MASK(pwm->hwpwm),
+ PWM_CV1800_REG_ENABLE(pwm->hwpwm));
+ regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
+ PWM_CV1800_UPDATE_MASK(pwm->hwpwm),
+ PWM_CV1800_REG_DISABLE);
+ } else if (!pwm_enable && enable) {
+ regmap_update_bits(priv->map, PWM_CV1800_START,
+ PWM_CV1800_START_MASK(pwm->hwpwm),
+ PWM_CV1800_REG_ENABLE(pwm->hwpwm));
+ } else if (pwm_enable && !enable) {
+ regmap_update_bits(priv->map, PWM_CV1800_START,
+ PWM_CV1800_START_MASK(pwm->hwpwm),
+ PWM_CV1800_REG_DISABLE);
+ }
+
+ return 0;
+}
+
+static void cv1800_pwm_set_polarity(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ enum pwm_polarity polarity)
+{
+ struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
+
+ if (pwm->state.enabled)
+ cv1800_pwm_enable(chip, pwm, !pwm->state.enabled);
+
+ if (polarity == PWM_POLARITY_INVERSED)
+ regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
+ PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
+ PWM_CV1800_REG_ENABLE(pwm->hwpwm));
+ else
+ regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
+ PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
+ PWM_CV1800_REG_DISABLE);
+}
+
+static void cv1800_pwm_set_oe(struct pwm_chip *chip, struct pwm_device *pwm,
+ u32 mode)
+{
+ struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
+ u32 state;
+
+ regmap_read(priv->map, PWM_CV1800_OE, &state);
+ state &= PWM_CV1800_OE_MASK(pwm->hwpwm);
+
+ if (state == mode)
+ return;
+
+ cv1800_pwm_enable(chip, pwm, false);
+
+ if (mode == PWM_CV1800_OE_INPUT)
+ regmap_update_bits(priv->map, PWM_CV1800_OE,
+ PWM_CV1800_OE_MASK(pwm->hwpwm),
+ PWM_CV1800_REG_DISABLE);
+ else if (mode == PWM_CV1800_OE_OUTPUT(pwm->hwpwm))
+ regmap_update_bits(priv->map, PWM_CV1800_OE,
+ PWM_CV1800_OE_MASK(pwm->hwpwm),
+ PWM_CV1800_REG_ENABLE(pwm->hwpwm));
+}
+
+static int cv1800_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
+ u32 period_val, hlperiod_val;
+ u64 tem;
+
+ cv1800_pwm_set_oe(chip, pwm, PWM_CV1800_OE_OUTPUT(pwm->hwpwm));
+
+ if (state->polarity != pwm->state.polarity)
+ cv1800_pwm_set_polarity(chip, pwm, state->polarity);
+
+ /*
+ * This hardware use PERIOD and HLPERIOD registers to represent PWM waves.
+ *
+ * The meaning of PERIOD is how many clock cycles (from the clock source)
+ * are used to represent PWM waves.
+ * PERIOD = rate(MHz) / target(MHz)
+ * PERIOD = period(ns) * rate(Hz) / NSEC_PER_SEC
+ */
+ tem = mul_u64_u64_div_u64(state->period, priv->clk_rate, NSEC_PER_SEC);
+ if (tem < PWM_CV1800_MINPERIOD)
+ return -EINVAL;
+
+ if (tem > PWM_CV1800_MAXPERIOD)
+ tem = PWM_CV1800_MAXPERIOD;
+
+ period_val = (u32)tem;
+
+ /*
+ * The meaning of HLPERIOD is the number of beats in the low or high level
+ * of the PERIOD. When the value of the POLARITY register is 0, HLPERIOD
+ * represents a low level.
+ * HLPERIOD = period_val - rate(MHz) / duty(MHz)
+ * HLPERIOD = period_val - duty(ns) * rate(Hz) / NSEC_PER_SEC
+ */
+ tem = mul_u64_u64_div_u64(state->duty_cycle, priv->clk_rate,
+ NSEC_PER_SEC);
+ if (tem > period_val)
+ return -EINVAL;
+ hlperiod_val = period_val - (u32)tem;
+
+ regmap_write(priv->map, PWM_CV1800_PERIOD(pwm->hwpwm), period_val);
+ regmap_write(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), hlperiod_val);
+
+ cv1800_pwm_enable(chip, pwm, state->enabled);
+
+ return 0;
+}
+
+static int cv1800_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
+ u32 period_val, hlperiod_val;
+ u64 period_ns = 0;
+ u64 duty_ns = 0;
+ u32 enable = 0;
+ u32 polarity = 0;
+
+ regmap_read(priv->map, PWM_CV1800_PERIOD(pwm->hwpwm), &period_val);
+ regmap_read(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), &hlperiod_val);
+
+ if (period_val != PWM_CV1800_PERIOD_RESET ||
+ hlperiod_val != PWM_CV1800_HLPERIOD_RESET) {
+ period_ns = DIV_ROUND_UP_ULL(period_val * NSEC_PER_SEC,
+ priv->clk_rate);
+ duty_ns = DIV_ROUND_UP_ULL(hlperiod_val * period_ns, period_val);
+
+ regmap_read(priv->map, PWM_CV1800_START, &enable);
+ enable &= PWM_CV1800_START_MASK(pwm->hwpwm);
+
+ regmap_read(priv->map, PWM_CV1800_POLARITY, &polarity);
+ polarity &= PWM_CV1800_POLARITY_MASK(pwm->hwpwm);
+ }
+
+ state->period = period_ns;
+ state->duty_cycle = duty_ns;
+ state->enabled = enable;
+ state->polarity = polarity ? PWM_POLARITY_INVERSED : PWM_POLARITY_NORMAL;
+
+ return 0;
+}
+
+static const struct pwm_ops cv1800_pwm_ops = {
+ .apply = cv1800_pwm_apply,
+ .get_state = cv1800_pwm_get_state,
+};
+
+static void devm_clk_rate_exclusive_put(void *data)
+{
+ struct clk *clk = data;
+
+ clk_rate_exclusive_put(clk);
+}
+
+static int cv1800_pwm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct cv1800_pwm *priv;
+ struct pwm_chip *chip;
+ void __iomem *base;
+ int ret;
+
+ chip = devm_pwmchip_alloc(dev, PWM_CV1800_CHANNELS, sizeof(*priv));
+ if (!chip)
+ return PTR_ERR(chip);
+ priv = to_cv1800_pwm_dev(chip);
+
+ base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ priv->map = devm_regmap_init_mmio(&pdev->dev, base,
+ &cv1800_pwm_regmap_config);
+ if (IS_ERR(priv->map))
+ return PTR_ERR(priv->map);
+
+ priv->clk = devm_clk_get_enabled(&pdev->dev, NULL);
+ if (IS_ERR(priv->clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk),
+ "clk not found\n");
+
+ ret = clk_rate_exclusive_get(priv->clk);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "failed to get exclusive rate\n");
+
+ ret = devm_add_action_or_reset(&pdev->dev, devm_clk_rate_exclusive_put,
+ priv->clk);
+ if (ret) {
+ clk_rate_exclusive_put(priv->clk);
+ return ret;
+ }
+
+ priv->clk_rate = clk_get_rate(priv->clk);
+ if (!priv->clk_rate)
+ return dev_err_probe(&pdev->dev, -EINVAL,
+ "Invalid clock rate: %lu\n",
+ priv->clk_rate);
+
+ chip->ops = &cv1800_pwm_ops;
+
+ return devm_pwmchip_add(dev, chip);
+}
+
+static const struct of_device_id cv1800_pwm_dt_ids[] = {
+ { .compatible = "sophgo,cv1800-pwm" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, cv1800_pwm_dt_ids);
+
+static struct platform_driver cv1800_pwm_driver = {
+ .probe = cv1800_pwm_probe,
+ .driver = {
+ .name = "cv1800-pwm",
+ .of_match_table = cv1800_pwm_dt_ids,
+ },
+};
+module_platform_driver(cv1800_pwm_driver);
+
+MODULE_AUTHOR("Jingbao Qiu");
+MODULE_DESCRIPTION("Sophgo cv1800 PWM Driver");
+MODULE_LICENSE("GPL");
--
2.25.1
On 04/03/2024 10:02, Jingbao Qiu wrote:
> Implement the PWM driver for CV1800.
>
> Signed-off-by: Jingbao Qiu <[email protected]>
..
> +
> + ret = devm_add_action_or_reset(&pdev->dev, devm_clk_rate_exclusive_put,
> + priv->clk);
> + if (ret) {
> + clk_rate_exclusive_put(priv->clk);
> + return ret;
Please test this path - you have double put.
Best regards,
Krzysztof
On Mon, Mar 4, 2024 at 6:15 PM Krzysztof Kozlowski
<[email protected]> wrote:
>
> On 04/03/2024 10:02, Jingbao Qiu wrote:
> > Implement the PWM driver for CV1800.
> >
> > Signed-off-by: Jingbao Qiu <[email protected]>
>
> ...
>
> > +
> > + ret = devm_add_action_or_reset(&pdev->dev, devm_clk_rate_exclusive_put,
> > + priv->clk);
> > + if (ret) {
> > + clk_rate_exclusive_put(priv->clk);
> > + return ret;
>
> Please test this path - you have double put.
>
Thank you for your reply. You're right. If the
devm_add_action_or_reset() function
fails to add an action, it will call the action.
By the way, if I need to resend the patch, should I wait for the
maintainer to review it, or
should I immediately correct this error and resend it.
Best regards,
Jingbao Qiu
On 04/03/2024 14:40, Jingbao Qiu wrote:
> On Mon, Mar 4, 2024 at 6:15 PM Krzysztof Kozlowski
> <[email protected]> wrote:
>>
>> On 04/03/2024 10:02, Jingbao Qiu wrote:
>>> Implement the PWM driver for CV1800.
>>>
>>> Signed-off-by: Jingbao Qiu <[email protected]>
>>
>> ...
>>
>>> +
>>> + ret = devm_add_action_or_reset(&pdev->dev, devm_clk_rate_exclusive_put,
>>> + priv->clk);
>>> + if (ret) {
>>> + clk_rate_exclusive_put(priv->clk);
>>> + return ret;
>>
>> Please test this path - you have double put.
>>
>
> Thank you for your reply. You're right. If the
> devm_add_action_or_reset() function
> fails to add an action, it will call the action.
>
> By the way, if I need to resend the patch, should I wait for the
> maintainer to review it, or
> should I immediately correct this error and resend it.
I recommend one patchset per day.
Best regards,
Krzysztof
Hello,
thanks for your patch.
On Mon, Mar 04, 2024 at 05:02:48PM +0800, Jingbao Qiu wrote:
> Implement the PWM driver for CV1800.
>
> Signed-off-by: Jingbao Qiu <[email protected]>
> ---
> drivers/pwm/Kconfig | 10 ++
> drivers/pwm/Makefile | 1 +
> drivers/pwm/pwm-cv1800.c | 314 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 325 insertions(+)
> create mode 100644 drivers/pwm/pwm-cv1800.c
>
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 4b956d661755..455f07af94f7 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -186,6 +186,16 @@ config PWM_CROS_EC
> PWM driver for exposing a PWM attached to the ChromeOS Embedded
> Controller.
>
> +config PWM_CV1800
> + tristate "Sophgo CV1800 PWM driver"
> + depends on ARCH_SOPHGO || COMPILE_TEST
> + help
> + Generic PWM framework driver for the Sophgo CV1800 series
> + SoCs.
> +
> + To compile this driver as a module, build the dependecies
> + as modules, this will be called pwm-cv1800.
> +
> config PWM_DWC_CORE
> tristate
> depends on HAS_IOMEM
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index c5ec9e168ee7..6c3c4a07a316 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -15,6 +15,7 @@ obj-$(CONFIG_PWM_CLK) += pwm-clk.o
> obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o
> obj-$(CONFIG_PWM_CRC) += pwm-crc.o
> obj-$(CONFIG_PWM_CROS_EC) += pwm-cros-ec.o
> +obj-$(CONFIG_PWM_CV1800) += pwm-cv1800.o
> obj-$(CONFIG_PWM_DWC_CORE) += pwm-dwc-core.o
> obj-$(CONFIG_PWM_DWC) += pwm-dwc.o
> obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o
> diff --git a/drivers/pwm/pwm-cv1800.c b/drivers/pwm/pwm-cv1800.c
> new file mode 100644
> index 000000000000..d5b31a2b7787
> --- /dev/null
> +++ b/drivers/pwm/pwm-cv1800.c
> @@ -0,0 +1,314 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * pwm-cv1800.c: PWM driver for Sophgo cv1800
Mentioning the filename in the file isn't very helpful. It's obvious
information.
> + * Author: Jingbao Qiu <[email protected]>
> + *
> + * Limitations:
> + * - It output low when PWM channel disabled.
> + * - This pwm device supports dynamic loading of PWM parameters. When PWMSTART
> + * is written from 0 to 1, the register value (HLPERIODn, PERIODn) will be
> + * temporarily stored inside the PWM. If you want to dynamically change the
> + * waveform during PWM output, after writing the new value to HLPERIODn and
> + * PERIODn, write 1 and then 0 to PWMUPDATE[n] to make the new value effective.
> + * - Supports up to Rate/2 output, and the lowest is about Rate/(2^30-1).
> + * - By setting HLPERIODn to 0, can produce 100% duty cycle.
> + * - This hardware could support inverted polarity. By default, the value of the
> + * POLARITY register is 0x0. This means that HLPERIOD represents the number
> + * of low level beats.
> + * - This hardware supports input mode and output mode, implemented through the
> + * Output-Enable/OE register. However, this driver has not yet implemented
> + * capture callback.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/regmap.h>
> +
> +#define PWM_CV1800_HLPERIOD_BASE 0x00
> +#define PWM_CV1800_PERIOD_BASE 0x04
> +#define PWM_CV1800_POLARITY 0x40
> +#define PWM_CV1800_START 0x44
> +#define PWM_CV1800_DONE 0x48
> +#define PWM_CV1800_UPDATE 0x4c
> +#define PWM_CV1800_OE 0xd0
> +
> +#define PWM_CV1800_HLPERIOD(n) (PWM_CV1800_HLPERIOD_BASE + ((n) * 0x08))
> +#define PWM_CV1800_PERIOD(n) (PWM_CV1800_PERIOD_BASE + ((n) * 0x08))
> +
> +#define PWM_CV1800_UPDATE_MASK(n) (BIT(0) << (n))
> +#define PWM_CV1800_OE_MASK(n) (BIT(0) << (n))
> +#define PWM_CV1800_START_MASK(n) (BIT(0) << (n))
> +#define PWM_CV1800_POLARITY_MASK(n) (BIT(0) << (n))
> +
> +#define PWM_CV1800_OE_INPUT 0x00U
> +#define PWM_CV1800_OE_OUTPUT(n) (BIT(0) << (n))
> +#define PWM_CV1800_MAXPERIOD (BIT(30) - 1)
> +#define PWM_CV1800_MINPERIOD BIT(1)
These are minimal and maximal values. I'd do
#define PWM_CV1800_MAXPERIOD 0x3fffffff
#define PWM_CV1800_MINPERIOD 2
> +#define PWM_CV1800_PERIOD_RESET BIT(1)
> +#define PWM_CV1800_HLPERIOD_RESET BIT(0)
> +#define PWM_CV1800_REG_DISABLE 0x00U
> +#define PWM_CV1800_REG_ENABLE(n) (BIT(0) << (n))
> +#define PWM_CV1800_CHANNELS 4
> +
> +struct cv1800_pwm {
> + struct regmap *map;
> + struct clk *clk;
> + unsigned long clk_rate;
> +};
> +
> +static inline struct cv1800_pwm *to_cv1800_pwm_dev(struct pwm_chip *chip)
> +{
> + return pwmchip_get_drvdata(chip);
> +}
> +
> +static const struct regmap_config cv1800_pwm_regmap_config = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = 4,
> +};
> +
> +static int cv1800_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm,
> + bool enable)
> +{
> + struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> + u32 pwm_enable;
> +
> + regmap_read(priv->map, PWM_CV1800_START, &pwm_enable);
> + pwm_enable &= PWM_CV1800_START_MASK(pwm->hwpwm);
> +
> + /*
> + * If the parameters are changed during runtime, Register needs
> + * to be updated to take effect.
> + */
> + if (pwm_enable && enable) {
> + regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
> + PWM_CV1800_UPDATE_MASK(pwm->hwpwm),
> + PWM_CV1800_REG_ENABLE(pwm->hwpwm));
> + regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
> + PWM_CV1800_UPDATE_MASK(pwm->hwpwm),
> + PWM_CV1800_REG_DISABLE);
> + } else if (!pwm_enable && enable) {
> + regmap_update_bits(priv->map, PWM_CV1800_START,
> + PWM_CV1800_START_MASK(pwm->hwpwm),
> + PWM_CV1800_REG_ENABLE(pwm->hwpwm));
> + } else if (pwm_enable && !enable) {
> + regmap_update_bits(priv->map, PWM_CV1800_START,
> + PWM_CV1800_START_MASK(pwm->hwpwm),
> + PWM_CV1800_REG_DISABLE);
> + }
> +
> + return 0;
> +}
> +
> +static void cv1800_pwm_set_polarity(struct pwm_chip *chip,
> + struct pwm_device *pwm,
> + enum pwm_polarity polarity)
> +{
> + struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> +
> + if (pwm->state.enabled)
> + cv1800_pwm_enable(chip, pwm, !pwm->state.enabled);
> +
> + if (polarity == PWM_POLARITY_INVERSED)
> + regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
> + PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
> + PWM_CV1800_REG_ENABLE(pwm->hwpwm));
> + else
> + regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
> + PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
> + PWM_CV1800_REG_DISABLE);
Wouldn't it be more natural to make this read:
if (polarity == PWM_POLARITY_INVERSED)
regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
PWM_CV1800_POLARITY_MASK(pwm->hwpwm));
else
regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
0);
or even:
u32 polarity = 0;
if (polarity == PWM_POLARITY_INVERSED)
polarity = PWM_CV1800_POLARITY_MASK(pwm->hwpwm);
regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
polarity);
?
> +}
> +
> +static void cv1800_pwm_set_oe(struct pwm_chip *chip, struct pwm_device *pwm,
> + u32 mode)
> +{
> + struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> + u32 state;
> +
> + regmap_read(priv->map, PWM_CV1800_OE, &state);
> + state &= PWM_CV1800_OE_MASK(pwm->hwpwm);
> +
> + if (state == mode)
> + return;
> +
> + cv1800_pwm_enable(chip, pwm, false);
> +
> + if (mode == PWM_CV1800_OE_INPUT)
> + regmap_update_bits(priv->map, PWM_CV1800_OE,
> + PWM_CV1800_OE_MASK(pwm->hwpwm),
> + PWM_CV1800_REG_DISABLE);
> + else if (mode == PWM_CV1800_OE_OUTPUT(pwm->hwpwm))
> + regmap_update_bits(priv->map, PWM_CV1800_OE,
> + PWM_CV1800_OE_MASK(pwm->hwpwm),
> + PWM_CV1800_REG_ENABLE(pwm->hwpwm));
> +}
What does this function do? A comment describing that would be good. I
wonder about it being called unconditionally in .apply() below.
> +
> +static int cv1800_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> + const struct pwm_state *state)
> +{
> + struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> + u32 period_val, hlperiod_val;
> + u64 tem;
> +
> + cv1800_pwm_set_oe(chip, pwm, PWM_CV1800_OE_OUTPUT(pwm->hwpwm));
> +
> + if (state->polarity != pwm->state.polarity)
> + cv1800_pwm_set_polarity(chip, pwm, state->polarity);
> +
> + /*
> + * This hardware use PERIOD and HLPERIOD registers to represent PWM waves.
> + *
> + * The meaning of PERIOD is how many clock cycles (from the clock source)
> + * are used to represent PWM waves.
> + * PERIOD = rate(MHz) / target(MHz)
> + * PERIOD = period(ns) * rate(Hz) / NSEC_PER_SEC
> + */
> + tem = mul_u64_u64_div_u64(state->period, priv->clk_rate, NSEC_PER_SEC);
What does "tem" stand for? Maybe "ticks" is a better name?
> + if (tem < PWM_CV1800_MINPERIOD)
> + return -EINVAL;
> +
> + if (tem > PWM_CV1800_MAXPERIOD)
> + tem = PWM_CV1800_MAXPERIOD;
> +
> + period_val = (u32)tem;
> +
> + /*
> + * The meaning of HLPERIOD is the number of beats in the low or high level
> + * of the PERIOD. When the value of the POLARITY register is 0, HLPERIOD
> + * represents a low level.
> + * HLPERIOD = period_val - rate(MHz) / duty(MHz)
> + * HLPERIOD = period_val - duty(ns) * rate(Hz) / NSEC_PER_SEC
So HLPERIOD defines the second part of each period, right? This isn't
considered in .get_state().
> + */
> + tem = mul_u64_u64_div_u64(state->duty_cycle, priv->clk_rate,
> + NSEC_PER_SEC);
> + if (tem > period_val)
> + return -EINVAL;
if (tem > period_val)
tem = period_val;
> + hlperiod_val = period_val - (u32)tem;
Wrong rounding I think. Did you test your driver with PWM_DEBUG enabled?
> + regmap_write(priv->map, PWM_CV1800_PERIOD(pwm->hwpwm), period_val);
> + regmap_write(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), hlperiod_val);
> +
> + cv1800_pwm_enable(chip, pwm, state->enabled);
> +
> + return 0;
> +}
> +
> +static int cv1800_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
> + struct pwm_state *state)
> +{
> + struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> + u32 period_val, hlperiod_val;
> + u64 period_ns = 0;
> + u64 duty_ns = 0;
> + u32 enable = 0;
> + u32 polarity = 0;
> +
> + regmap_read(priv->map, PWM_CV1800_PERIOD(pwm->hwpwm), &period_val);
> + regmap_read(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), &hlperiod_val);
> +
> + if (period_val != PWM_CV1800_PERIOD_RESET ||
> + hlperiod_val != PWM_CV1800_HLPERIOD_RESET) {
> + period_ns = DIV_ROUND_UP_ULL(period_val * NSEC_PER_SEC,
> + priv->clk_rate);
> + duty_ns = DIV_ROUND_UP_ULL(hlperiod_val * period_ns, period_val);
> +
> + regmap_read(priv->map, PWM_CV1800_START, &enable);
> + enable &= PWM_CV1800_START_MASK(pwm->hwpwm);
> +
> + regmap_read(priv->map, PWM_CV1800_POLARITY, &polarity);
> + polarity &= PWM_CV1800_POLARITY_MASK(pwm->hwpwm);
> + }
> +
> + state->period = period_ns;
> + state->duty_cycle = duty_ns;
> + state->enabled = enable;
> + state->polarity = polarity ? PWM_POLARITY_INVERSED : PWM_POLARITY_NORMAL;
> +
> + return 0;
> +}
> +
> +static const struct pwm_ops cv1800_pwm_ops = {
> + .apply = cv1800_pwm_apply,
> + .get_state = cv1800_pwm_get_state,
> +};
> +
> +static void devm_clk_rate_exclusive_put(void *data)
> +{
> + struct clk *clk = data;
> +
> + clk_rate_exclusive_put(clk);
> +}
> +
> +static int cv1800_pwm_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct cv1800_pwm *priv;
> + struct pwm_chip *chip;
> + void __iomem *base;
> + int ret;
> +
> + chip = devm_pwmchip_alloc(dev, PWM_CV1800_CHANNELS, sizeof(*priv));
> + if (!chip)
> + return PTR_ERR(chip);
> + priv = to_cv1800_pwm_dev(chip);
> +
> + base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(base))
> + return PTR_ERR(base);
> +
> + priv->map = devm_regmap_init_mmio(&pdev->dev, base,
> + &cv1800_pwm_regmap_config);
> + if (IS_ERR(priv->map))
> + return PTR_ERR(priv->map);
> +
> + priv->clk = devm_clk_get_enabled(&pdev->dev, NULL);
> + if (IS_ERR(priv->clk))
> + return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk),
> + "clk not found\n");
> +
> + ret = clk_rate_exclusive_get(priv->clk);
There is a devm_clk_rate_exclusive_get() in next. Please make use of it.
(See commit b0cde62e4c54)
> + if (ret)
> + return dev_err_probe(&pdev->dev, ret,
> + "failed to get exclusive rate\n");
> +
> + ret = devm_add_action_or_reset(&pdev->dev, devm_clk_rate_exclusive_put,
> + priv->clk);
> + if (ret) {
> + clk_rate_exclusive_put(priv->clk);
> + return ret;
> + }
> +
> + priv->clk_rate = clk_get_rate(priv->clk);
> + if (!priv->clk_rate)
> + return dev_err_probe(&pdev->dev, -EINVAL,
> + "Invalid clock rate: %lu\n",
> + priv->clk_rate);
> +
> + chip->ops = &cv1800_pwm_ops;
> +
> + return devm_pwmchip_add(dev, chip);
Error message if devm_pwmchip_add() fails, please.
> +}
> +
> +static const struct of_device_id cv1800_pwm_dt_ids[] = {
> + { .compatible = "sophgo,cv1800-pwm" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, cv1800_pwm_dt_ids);
> +
> +static struct platform_driver cv1800_pwm_driver = {
> + .probe = cv1800_pwm_probe,
> + .driver = {
> + .name = "cv1800-pwm",
> + .of_match_table = cv1800_pwm_dt_ids,
> + },
> +};
> +module_platform_driver(cv1800_pwm_driver);
> +
> +MODULE_AUTHOR("Jingbao Qiu");
> +MODULE_DESCRIPTION("Sophgo cv1800 PWM Driver");
> +MODULE_LICENSE("GPL");
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | https://www.pengutronix.de/ |
On Mon, Mar 4, 2024 at 11:02 PM Krzysztof Kozlowski
<[email protected]> wrote:
>
> On 04/03/2024 14:40, Jingbao Qiu wrote:
> > On Mon, Mar 4, 2024 at 6:15 PM Krzysztof Kozlowski
> > <[email protected]> wrote:
> >>
> >> On 04/03/2024 10:02, Jingbao Qiu wrote:
> >>> Implement the PWM driver for CV1800.
> >>>
> >>> Signed-off-by: Jingbao Qiu <[email protected]>
> >>
> >> ...
> >>
> >>> +
> >>> + ret = devm_add_action_or_reset(&pdev->dev, devm_clk_rate_exclusive_put,
> >>> + priv->clk);
> >>> + if (ret) {
> >>> + clk_rate_exclusive_put(priv->clk);
> >>> + return ret;
> >>
> >> Please test this path - you have double put.
> >>
> >
> > Thank you for your reply. You're right. If the
> > devm_add_action_or_reset() function
> > fails to add an action, it will call the action.
> >
> > By the way, if I need to resend the patch, should I wait for the
> > maintainer to review it, or
> > should I immediately correct this error and resend it.
>
> I recommend one patchset per day.
>
Thank you for your suggestion.
Best regards,
Jingbao Qiu
Hi Uwe,
On Mon, Mar 4, 2024 at 11:37 PM Uwe Kleine-König
<[email protected]> wrote:
>
> Hello,
>
> thanks for your patch.
>
> On Mon, Mar 04, 2024 at 05:02:48PM +0800, Jingbao Qiu wrote:
> > Implement the PWM driver for CV1800.
> >
> > Signed-off-by: Jingbao Qiu <[email protected]>
> > ---
> > drivers/pwm/Kconfig | 10 ++
> > drivers/pwm/Makefile | 1 +
> > drivers/pwm/pwm-cv1800.c | 314 +++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 325 insertions(+)
> > create mode 100644 drivers/pwm/pwm-cv1800.c
> >
> > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> > index 4b956d661755..455f07af94f7 100644
> > --- a/drivers/pwm/Kconfig
> > +++ b/drivers/pwm/Kconfig
> > @@ -186,6 +186,16 @@ config PWM_CROS_EC
> > PWM driver for exposing a PWM attached to the ChromeOS Embedded
> > Controller.
> >
> > +config PWM_CV1800
> > + tristate "Sophgo CV1800 PWM driver"
> > + depends on ARCH_SOPHGO || COMPILE_TEST
> > + help
> > + Generic PWM framework driver for the Sophgo CV1800 series
> > + SoCs.
> > +
> > + To compile this driver as a module, build the dependecies
> > + as modules, this will be called pwm-cv1800.
> > +
> > config PWM_DWC_CORE
> > tristate
> > depends on HAS_IOMEM
> > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> > index c5ec9e168ee7..6c3c4a07a316 100644
> > --- a/drivers/pwm/Makefile
> > +++ b/drivers/pwm/Makefile
> > @@ -15,6 +15,7 @@ obj-$(CONFIG_PWM_CLK) += pwm-clk.o
> > obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o
> > obj-$(CONFIG_PWM_CRC) += pwm-crc.o
> > obj-$(CONFIG_PWM_CROS_EC) += pwm-cros-ec.o
> > +obj-$(CONFIG_PWM_CV1800) += pwm-cv1800.o
> > obj-$(CONFIG_PWM_DWC_CORE) += pwm-dwc-core.o
> > obj-$(CONFIG_PWM_DWC) += pwm-dwc.o
> > obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o
> > diff --git a/drivers/pwm/pwm-cv1800.c b/drivers/pwm/pwm-cv1800.c
> > new file mode 100644
> > index 000000000000..d5b31a2b7787
> > --- /dev/null
> > +++ b/drivers/pwm/pwm-cv1800.c
> > @@ -0,0 +1,314 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * pwm-cv1800.c: PWM driver for Sophgo cv1800
>
> Mentioning the filename in the file isn't very helpful. It's obvious
> information.
I will drop this line.
>
> > + * Author: Jingbao Qiu <[email protected]>
> > + *
> > + * Limitations:
> > + * - It output low when PWM channel disabled.
> > + * - This pwm device supports dynamic loading of PWM parameters. When PWMSTART
> > + * is written from 0 to 1, the register value (HLPERIODn, PERIODn) will be
> > + * temporarily stored inside the PWM. If you want to dynamically change the
> > + * waveform during PWM output, after writing the new value to HLPERIODn and
> > + * PERIODn, write 1 and then 0 to PWMUPDATE[n] to make the new value effective.
> > + * - Supports up to Rate/2 output, and the lowest is about Rate/(2^30-1).
> > + * - By setting HLPERIODn to 0, can produce 100% duty cycle.
> > + * - This hardware could support inverted polarity. By default, the value of the
> > + * POLARITY register is 0x0. This means that HLPERIOD represents the number
> > + * of low level beats.
> > + * - This hardware supports input mode and output mode, implemented through the
> > + * Output-Enable/OE register. However, this driver has not yet implemented
> > + * capture callback.
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/pwm.h>
> > +#include <linux/regmap.h>
> > +
> > +#define PWM_CV1800_HLPERIOD_BASE 0x00
> > +#define PWM_CV1800_PERIOD_BASE 0x04
> > +#define PWM_CV1800_POLARITY 0x40
> > +#define PWM_CV1800_START 0x44
> > +#define PWM_CV1800_DONE 0x48
> > +#define PWM_CV1800_UPDATE 0x4c
> > +#define PWM_CV1800_OE 0xd0
> > +
> > +#define PWM_CV1800_HLPERIOD(n) (PWM_CV1800_HLPERIOD_BASE + ((n) * 0x08))
> > +#define PWM_CV1800_PERIOD(n) (PWM_CV1800_PERIOD_BASE + ((n) * 0x08))
> > +
> > +#define PWM_CV1800_UPDATE_MASK(n) (BIT(0) << (n))
> > +#define PWM_CV1800_OE_MASK(n) (BIT(0) << (n))
> > +#define PWM_CV1800_START_MASK(n) (BIT(0) << (n))
> > +#define PWM_CV1800_POLARITY_MASK(n) (BIT(0) << (n))
> > +
> > +#define PWM_CV1800_OE_INPUT 0x00U
> > +#define PWM_CV1800_OE_OUTPUT(n) (BIT(0) << (n))
> > +#define PWM_CV1800_MAXPERIOD (BIT(30) - 1)
> > +#define PWM_CV1800_MINPERIOD BIT(1)
>
> These are minimal and maximal values. I'd do
>
> #define PWM_CV1800_MAXPERIOD 0x3fffffff
> #define PWM_CV1800_MINPERIOD 2
>
I will fix it.
> > +#define PWM_CV1800_PERIOD_RESET BIT(1)
> > +#define PWM_CV1800_HLPERIOD_RESET BIT(0)
> > +#define PWM_CV1800_REG_DISABLE 0x00U
> > +#define PWM_CV1800_REG_ENABLE(n) (BIT(0) << (n))
> > +#define PWM_CV1800_CHANNELS 4
> > +
> > +struct cv1800_pwm {
> > + struct regmap *map;
> > + struct clk *clk;
> > + unsigned long clk_rate;
> > +};
> > +
> > +static inline struct cv1800_pwm *to_cv1800_pwm_dev(struct pwm_chip *chip)
> > +{
> > + return pwmchip_get_drvdata(chip);
> > +}
> > +
> > +static const struct regmap_config cv1800_pwm_regmap_config = {
> > + .reg_bits = 32,
> > + .val_bits = 32,
> > + .reg_stride = 4,
> > +};
> > +
> > +static int cv1800_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm,
> > + bool enable)
> > +{
> > + struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> > + u32 pwm_enable;
> > +
> > + regmap_read(priv->map, PWM_CV1800_START, &pwm_enable);
> > + pwm_enable &= PWM_CV1800_START_MASK(pwm->hwpwm);
> > +
> > + /*
> > + * If the parameters are changed during runtime, Register needs
> > + * to be updated to take effect.
> > + */
> > + if (pwm_enable && enable) {
> > + regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
> > + PWM_CV1800_UPDATE_MASK(pwm->hwpwm),
> > + PWM_CV1800_REG_ENABLE(pwm->hwpwm));
> > + regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
> > + PWM_CV1800_UPDATE_MASK(pwm->hwpwm),
> > + PWM_CV1800_REG_DISABLE);
> > + } else if (!pwm_enable && enable) {
> > + regmap_update_bits(priv->map, PWM_CV1800_START,
> > + PWM_CV1800_START_MASK(pwm->hwpwm),
> > + PWM_CV1800_REG_ENABLE(pwm->hwpwm));
> > + } else if (pwm_enable && !enable) {
> > + regmap_update_bits(priv->map, PWM_CV1800_START,
> > + PWM_CV1800_START_MASK(pwm->hwpwm),
> > + PWM_CV1800_REG_DISABLE);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static void cv1800_pwm_set_polarity(struct pwm_chip *chip,
> > + struct pwm_device *pwm,
> > + enum pwm_polarity polarity)
> > +{
> > + struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> > +
> > + if (pwm->state.enabled)
> > + cv1800_pwm_enable(chip, pwm, !pwm->state.enabled);
> > +
> > + if (polarity == PWM_POLARITY_INVERSED)
> > + regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
> > + PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
> > + PWM_CV1800_REG_ENABLE(pwm->hwpwm));
> > + else
> > + regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
> > + PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
> > + PWM_CV1800_REG_DISABLE);
>
> Wouldn't it be more natural to make this read:
>
> if (polarity == PWM_POLARITY_INVERSED)
> regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
> PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
> PWM_CV1800_POLARITY_MASK(pwm->hwpwm));
> else
> regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
> PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
> 0);
>
> or even:
>
> u32 polarity = 0;
>
> if (polarity == PWM_POLARITY_INVERSED)
> polarity = PWM_CV1800_POLARITY_MASK(pwm->hwpwm);
>
> regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
> PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
> polarity);
>
> ?
>
Good idea. My code looks so bloated. I will fix it.
> > +}
> > +
> > +static void cv1800_pwm_set_oe(struct pwm_chip *chip, struct pwm_device *pwm,
> > + u32 mode)
> > +{
> > + struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> > + u32 state;
> > +
> > + regmap_read(priv->map, PWM_CV1800_OE, &state);
> > + state &= PWM_CV1800_OE_MASK(pwm->hwpwm);
> > +
> > + if (state == mode)
> > + return;
> > +
> > + cv1800_pwm_enable(chip, pwm, false);
> > +
> > + if (mode == PWM_CV1800_OE_INPUT)
> > + regmap_update_bits(priv->map, PWM_CV1800_OE,
> > + PWM_CV1800_OE_MASK(pwm->hwpwm),
> > + PWM_CV1800_REG_DISABLE);
> > + else if (mode == PWM_CV1800_OE_OUTPUT(pwm->hwpwm))
> > + regmap_update_bits(priv->map, PWM_CV1800_OE,
> > + PWM_CV1800_OE_MASK(pwm->hwpwm),
> > + PWM_CV1800_REG_ENABLE(pwm->hwpwm));
> > +}
>
> What does this function do? A comment describing that would be good. I
> wonder about it being called unconditionally in .apply() below.
I will add a comment for this function.
>
> > +
> > +static int cv1800_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> > + const struct pwm_state *state)
> > +{
> > + struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> > + u32 period_val, hlperiod_val;
> > + u64 tem;
> > +
> > + cv1800_pwm_set_oe(chip, pwm, PWM_CV1800_OE_OUTPUT(pwm->hwpwm));
> > +
> > + if (state->polarity != pwm->state.polarity)
> > + cv1800_pwm_set_polarity(chip, pwm, state->polarity);
> > +
> > + /*
> > + * This hardware use PERIOD and HLPERIOD registers to represent PWM waves.
> > + *
> > + * The meaning of PERIOD is how many clock cycles (from the clock source)
> > + * are used to represent PWM waves.
> > + * PERIOD = rate(MHz) / target(MHz)
> > + * PERIOD = period(ns) * rate(Hz) / NSEC_PER_SEC
> > + */
> > + tem = mul_u64_u64_div_u64(state->period, priv->clk_rate, NSEC_PER_SEC);
>
> What does "tem" stand for? Maybe "ticks" is a better name?
"ticks" looks better. I will use it.
>
> > + if (tem < PWM_CV1800_MINPERIOD)
> > + return -EINVAL;
> > +
> > + if (tem > PWM_CV1800_MAXPERIOD)
> > + tem = PWM_CV1800_MAXPERIOD;
> > +
> > + period_val = (u32)tem;
> > +
> > + /*
> > + * The meaning of HLPERIOD is the number of beats in the low or high level
> > + * of the PERIOD. When the value of the POLARITY register is 0, HLPERIOD
> > + * represents a low level.
> > + * HLPERIOD = period_val - rate(MHz) / duty(MHz)
> > + * HLPERIOD = period_val - duty(ns) * rate(Hz) / NSEC_PER_SEC
>
> So HLPERIOD defines the second part of each period, right? This isn't
> considered in .get_state().
I am so sorry about this. I made a mess of the duty cycle.
According to the PWM_DEBUG, it can be inferred that configure the
biggest duty_cycle not
bigger than the requested value, so in .apply duty_cycle should round down and
in .get_state duty_cycle should round up. However, when the polarity is normal,
This hardware requires a low-level beat count. So the corrected code
is as follows.
in .apply()
ticks = mul_u64_u64_div_u64(state->duty_cycle , priv->clk_rate,NSEC_PER_SEC);
..
hlperiod_val =period_val- (u32)ticks;
in .get_state()
u32 hlperiod_val=0;
period_ns = DIV_ROUND_UP_ULL(period_val * NSEC_PER_SEC,priv->clk_rate);
duty_ns = DIV_ROUND_UP_ULL(hlperiod_val * period_ns, period_val);
hlperiod_val = period_ns - duty_ns;
I tested this code with PWM_DEBUG. no warning output. What do you
think about this?
>
> > + */
> > + tem = mul_u64_u64_div_u64(state->duty_cycle, priv->clk_rate,
> > + NSEC_PER_SEC);
> > + if (tem > period_val)
> > + return -EINVAL;
>
> if (tem > period_val)
> tem = period_val;
>
> > + hlperiod_val = period_val - (u32)tem;
>
> Wrong rounding I think. Did you test your driver with PWM_DEBUG enabled?
ditto.
>
> > + regmap_write(priv->map, PWM_CV1800_PERIOD(pwm->hwpwm), period_val);
> > + regmap_write(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), hlperiod_val);
> > +
> > + cv1800_pwm_enable(chip, pwm, state->enabled);
> > +
> > + return 0;
> > +}
> > +
> > +static int cv1800_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
> > + struct pwm_state *state)
> > +{
> > + struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> > + u32 period_val, hlperiod_val;
> > + u64 period_ns = 0;
> > + u64 duty_ns = 0;
> > + u32 enable = 0;
> > + u32 polarity = 0;
> > +
> > + regmap_read(priv->map, PWM_CV1800_PERIOD(pwm->hwpwm), &period_val);
> > + regmap_read(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), &hlperiod_val);
> > +
> > + if (period_val != PWM_CV1800_PERIOD_RESET ||
> > + hlperiod_val != PWM_CV1800_HLPERIOD_RESET) {
> > + period_ns = DIV_ROUND_UP_ULL(period_val * NSEC_PER_SEC,
> > + priv->clk_rate);
> > + duty_ns = DIV_ROUND_UP_ULL(hlperiod_val * period_ns, period_val);
> > +
> > + regmap_read(priv->map, PWM_CV1800_START, &enable);
> > + enable &= PWM_CV1800_START_MASK(pwm->hwpwm);
> > +
> > + regmap_read(priv->map, PWM_CV1800_POLARITY, &polarity);
> > + polarity &= PWM_CV1800_POLARITY_MASK(pwm->hwpwm);
> > + }
> > +
> > + state->period = period_ns;
> > + state->duty_cycle = duty_ns;
> > + state->enabled = enable;
> > + state->polarity = polarity ? PWM_POLARITY_INVERSED : PWM_POLARITY_NORMAL;
> > +
> > + return 0;
> > +}
> > +
> > +static const struct pwm_ops cv1800_pwm_ops = {
> > + .apply = cv1800_pwm_apply,
> > + .get_state = cv1800_pwm_get_state,
> > +};
> > +
> > +static void devm_clk_rate_exclusive_put(void *data)
> > +{
> > + struct clk *clk = data;
> > +
> > + clk_rate_exclusive_put(clk);
> > +}
> > +
> > +static int cv1800_pwm_probe(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct cv1800_pwm *priv;
> > + struct pwm_chip *chip;
> > + void __iomem *base;
> > + int ret;
> > +
> > + chip = devm_pwmchip_alloc(dev, PWM_CV1800_CHANNELS, sizeof(*priv));
> > + if (!chip)
> > + return PTR_ERR(chip);
> > + priv = to_cv1800_pwm_dev(chip);
> > +
> > + base = devm_platform_ioremap_resource(pdev, 0);
> > + if (IS_ERR(base))
> > + return PTR_ERR(base);
> > +
> > + priv->map = devm_regmap_init_mmio(&pdev->dev, base,
> > + &cv1800_pwm_regmap_config);
> > + if (IS_ERR(priv->map))
> > + return PTR_ERR(priv->map);
> > +
> > + priv->clk = devm_clk_get_enabled(&pdev->dev, NULL);
> > + if (IS_ERR(priv->clk))
> > + return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk),
> > + "clk not found\n");
> > +
> > + ret = clk_rate_exclusive_get(priv->clk);
>
> There is a devm_clk_rate_exclusive_get() in next. Please make use of it.
> (See commit b0cde62e4c54)
I will use this branch.
>
> > + if (ret)
> > + return dev_err_probe(&pdev->dev, ret,
> > + "failed to get exclusive rate\n");> > +
> > + ret = devm_add_action_or_reset(&pdev->dev, devm_clk_rate_exclusive_put,
> > + priv->clk);
> > + if (ret) {
> > + clk_rate_exclusive_put(priv->clk);
> > + return ret;
> > + }
> > +
> > + priv->clk_rate = clk_get_rate(priv->clk);
> > + if (!priv->clk_rate)
> > + return dev_err_probe(&pdev->dev, -EINVAL,
> > + "Invalid clock rate: %lu\n",
> > + priv->clk_rate);
> > +
> > + chip->ops = &cv1800_pwm_ops;
> > +
> > + return devm_pwmchip_add(dev, chip);
>
> Error message if devm_pwmchip_add() fails, please.
I will fix it.
Thank you for your reply.
Best regards
Jingbao Qiu
Hi Uwe,
Gentle ping,
I'm sorry for wasting your time, and I look forward to your feedback.
> > > + if (tem < PWM_CV1800_MINPERIOD)
> > > + return -EINVAL;
> > > +
> > > + if (tem > PWM_CV1800_MAXPERIOD)
> > > + tem = PWM_CV1800_MAXPERIOD;
> > > +
> > > + period_val = (u32)tem;
> > > +
> > > + /*
> > > + * The meaning of HLPERIOD is the number of beats in the low or high level
> > > + * of the PERIOD. When the value of the POLARITY register is 0, HLPERIOD
> > > + * represents a low level.
> > > + * HLPERIOD = period_val - rate(MHz) / duty(MHz)
> > > + * HLPERIOD = period_val - duty(ns) * rate(Hz) / NSEC_PER_SEC
> >
> > So HLPERIOD defines the second part of each period, right? This isn't
> > considered in .get_state().
>
> I am so sorry about this. I made a mess of the duty cycle.
> According to the PWM_DEBUG, it can be inferred that configure the
> biggest duty_cycle not
> bigger than the requested value, so in .apply duty_cycle should round down and
> in .get_state duty_cycle should round up. However, when the polarity is normal,
> This hardware requires a low-level beat count. So the corrected code
> is as follows.
>
> in .apply()
>
> ticks = mul_u64_u64_div_u64(state->duty_cycle , priv->clk_rate,NSEC_PER_SEC);
> ...
> hlperiod_val =period_val- (u32)ticks;
>
> in .get_state()
>
> u32 hlperiod_val=0;
>
> period_ns = DIV_ROUND_UP_ULL(period_val * NSEC_PER_SEC,priv->clk_rate);
> duty_ns = DIV_ROUND_UP_ULL(hlperiod_val * period_ns, period_val);
> hlperiod_val = period_ns - duty_ns;
>
> I tested this code with PWM_DEBUG. no warning output. What do you
> think about this?
>
>
in .apply()
ticks = mul_u64_u64_div_u64(state->duty_cycle, priv->clk_rate,
NSEC_PER_SEC);
if (ticks > period_val)
ticks = period_val;
hlperiod_val = period_val - (u32)ticks;
..
regmap_write(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), hlperiod_val);
in .get_state()
u64 hlperiod_ns = 0;
regmap_read(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), &hlperiod_val);
..
period_ns = DIV_ROUND_UP_ULL(period_val * NSEC_PER_SEC,
priv->clk_rate);
hlperiod_ns = DIV_ROUND_UP_ULL(hlperiod_val * NSEC_PER_SEC,
priv->clk_rate);
duty_ns = period_ns - hlperiod_ns;
I tested this code with PWM_DEBUG. no warning output.
> >
> > > + */
> > > + tem = mul_u64_u64_div_u64(state->duty_cycle, priv->clk_rate,
> > > + NSEC_PER_SEC);
> > > + if (tem > period_val)
> > > + return -EINVAL;
> >
> > if (tem > period_val)
> > tem = period_val;
> >
> > > + hlperiod_val = period_val - (u32)tem;
> >
> > Wrong rounding I think. Did you test your driver with PWM_DEBUG enabled?
>
> ditto.
>
Best regards
Jingbao Qiu