[PATCH v10 0/2] pwm: Introduce pwm driver for the Loongson family chips

[Binbin Zhou <zhoubinbin@loongson.cn>]

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Hi all:

This patchset introduce a generic PWM framework driver for Loongson family.
Each PWM has one pulse width output signal and one pulse input signal to be measured.

It can be found on Loongson-2K series cpus and Loongson LS7A bridge chips.

Thanks.

-------
V10:
patch (1/2):
 - Put my s-o-b tag last;
 - Add \n between the includes and the dt node.

patch (2/2):
 - Put my s-o-b tag last;
 - Add comment about the hardware complete the currently running period
   when changing settings or disabling;
 - Add _REG to the prefix of the register field definitions, such as
   LOONGSON_PWM_CTRL_EN -> LOONGSON_PWM_CTRL_REG_EN;
 - Mark to_pwm_loongson_ddata function as __pure;
 - Handling "ddata->clk_rate" assertions in probe;
 - To guarantee that mul_u64_u64_div_u64() results in a value that fits into an u32.

Link to V9:
https://lore.kernel.org/all/cover.1739784071.git.zhoubinbin@loongson.cn/

V9:
patch(2/2):
 - Add error message to devm_clk_rate_exclusive_get();
 - Make all errors start with a capital letter;
 - Drop explicit initialization of the CTRL register in probe();
 - Add pwm->state.enabled check in pwm_loongson_suspend();
 - Drop pwm_loongson_suspend_store{ }.

Link to V8:
https://lore.kernel.org/all/cover.1733823417.git.zhoubinbin@loongson.cn/

V8:
patch (2/2):
 - Rebase on pwm/for-next;
 - Drop inappropriate comments in “Limitations”;
 - Drop HZ_PER_KHZ for readability;
 - NANOHZ_PER_HZ -> NSEC_PER_SEC;
 - Rewrite the clk fetch section to look more flexible and not have to
   care about ACPI or DT;
 - Add explicit initialization of the CTRL register in probe().

Link to V7:
https://lore.kernel.org/all/cover.1729583747.git.zhoubinbin@loongson.cn/

V7:
Thanks for Sean's advice.
patch (2/2):
 - Set chip->atomic to keep pwm_apply_atomic() can be used with the pwm.
 - Test with CONFIG_PWM_DEBUG and CONFIG_DEBUG_ATOMIC_SLEEP enabled.

Link to V6:
https://lore.kernel.org/all/cover.1728463622.git.zhoubinbin@loongson.cn/

V6:
patch (2/2):
 - Rebase on pwm/for-next;
 - Add Reference Manual;
 - Shortcut if !pwm->state.enabled;
 - When state->enabled is true, unconditionally execute
   pwm_loongson_set_polarity() to avoid that the polarity register is
   not set correctly.

Link to V5:
https://lore.kernel.org/all/cover.1720516327.git.zhoubinbin@loongson.cn/

V5:
patch (2/2):
 - Rebase on pwm/for-next;
 - Test with PWM_DEBUG enabled.
 - In pwm_loongson_apply(), the pwm state is determined before the pwm
   polarity, avoid test failures when PWM_DEBUG is enabled;
 - Added DIV64_U64_ROUND_UP in pwm_loongson_get_state() to avoid
   precision loss and to avoid test failures when PWM_DEBUG is enabled.

Link to V4:
https://lore.kernel.org/all/cover.1716795485.git.zhoubinbin@loongson.cn/

V4:
patch (2/2):
 - Rebase on pwm/for-next;
 - Addressed Uwe's review comments:
   - Make use of devm_pwmchip_alloc() function;
   - Add Limitations description;
   - Add LOONGSON_ prefix for Loongson pwm register defines;
   - Keep regs written only once;
   - Rewrite duty/period calculation;
   - Add dev_err_probe() in .probe();
   - Fix some code style.

Link to V3:
https://lore.kernel.org/linux-pwm/cover.1713164810.git.zhoubinbin@loongson.cn/

V3:
patch (1/2):
 - Add Reviewed-by tag from Krzysztof, thanks.
patch (2/2):
 - Several code stlye adjustments, such as line breaks.

Link to V2:
https://lore.kernel.org/all/cover.1712732719.git.zhoubinbin@loongson.cn/

v2:
- Remove the dts-related patches and update dts at once after all
relevant drivers are complete.
patch (1/2):
 - The dt-binding filename should match compatible, rename it as
   loongson,ls7a-pwm.yaml;
 - Update binding description;
 - Add description for each pwm cell;
 - Drop '#pwm-cells' from required, for pwm.yaml makes it required already.

Link to v1:
https://lore.kernel.org/linux-pwm/cover.1711953223.git.zhoubinbin@loongson.cn/

Binbin Zhou (2):
  dt-bindings: pwm: Add Loongson PWM controller
  pwm: Add Loongson PWM controller support

 .../bindings/pwm/loongson,ls7a-pwm.yaml       |  67 ++++
 MAINTAINERS                                   |   7 +
 drivers/pwm/Kconfig                           |  12 +
 drivers/pwm/Makefile                          |   1 +
 drivers/pwm/pwm-loongson.c                    | 290 ++++++++++++++++++
 5 files changed, 377 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/loongson,ls7a-pwm.yaml
 create mode 100644 drivers/pwm/pwm-loongson.c


base-commit: 6df320abbb40654085d7258de33d78481e93ac8d
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2.47.1