[v7,0/4] Add RZ/V2{M, MA} PWM driver support

Message

Fabrizio Castro Feb. 12, 2024, 9:06 p.m. UTC

The RZ/V2{M, MA} PWM Timer (PWM) is composed of 16 channels.
Linux is only allowed access to channels 8 to 14 on RZ/V2M,
while there is no restriction for RZ/V2MA.

The RZ/V2{M, MA} PWM Timer (PWM) supports the following functions:
 * The PWM has 24-bit counters which operate at PWM_CLK (48 MHz).
 * The frequency division ratio for internal counter operation is
   selectable as PWM_CLK divided by 1, 16, 256, or 2048.
 * The period as well as the duty cycle is adjustable.
 * The low-level and high-level order of the PWM signals can be
   inverted.
 * The duty cycle of the PWM signal is selectable in the range from
   0 to 100%.
 * The minimum resolution is 20.83 ns.
 * Three interrupt sources: Rising and falling edges of the PWM signal
   and clearing of the counter.
 * Counter operation and the bus interface are asynchronous and both can
   operate independently of the magnitude relationship of the respective
   clock periods.

v6->v7:
 * Addressed the build issue reported by the kernel test robot.
 * Replaced / with div64_u64 in driver.
 * Added rzv2m_pwm_mul_u64_u64_div_u64_rounddown to driver.
v5->v6:
 * Updated copyright in driver (2023->2024).
 * Several improvements to the driver, as suggested by Uwe.
v4->v5:
 * rebased to pwm for-next.
 * Sorted KConfig file
 * Sorted Make file
 * Updated copyright header 2022->2023.
 * Updated limitation section.
 * Replaced the variable chip->rzv2m_pwm in rzv2m_pwm_wait_delay()
 * Replaced polarity logic as per HW manual dutycycle = Ton/Ton+Toff, so
   eventhough native polarity is inverted from period point of view it
   is correct.
 * Updated logic for supporting 0% , 100% and remaining duty cycles.
 * On config() replaced
   pm_runtime_resume_and_get()->pm_runtime_get_sync()
 * Counter is stopped while updating period/polarity to avoid glitches.
 * Added error check for clk_prepare_enable()
 * Introduced is_ch_enabled variable to cache channel enable status.
 * clk_get_rate is called after enabling the clock and
   clk_rate_exclusive_get()
 * Added comment for delay
 * Replaced 1000000000UL->NSEC_PER_SEC.
 * Improved error handling in probe().
v3->v4:
 * Documented the hardware properties in "Limitations" section
 * Dropped the macros F2CYCLE_NSEC, U24_MASK and U24_MAX.
 * Added RZV2M_PWMCYC_PERIOD macro for U24_MAX
 * Dropped rzv2m_pwm_freq_div variable and started using 1 << (4 * i)
   for calculating divider as it is power of 16.
 * Reordered the functions to have rzv2m_pwm_config() directly before
   rzv2m_pwm_apply().
 * Improved the logic for calculating period and duty cycle in config()
 * Merged multiple RZV2M_PWMCTR register writes to a single write in
   config()
 * Replaced pwm_is_enabled()->pwm->state.enabled
 * Avoided assigning bit value as enum pwm_polarity instead used enum
   constant.
 * Fixed various issues in probe error path.
 * Updated the logic for PWM cycle setting register
 * A 100% duty cycle is only possible with PWMLOW > PWMCYC. So
   restricting PWMCYC values < 0xffffff
 * The native polarity of the hardware is inverted (i.e. it starts with
   the low part). So switched the inversion bit handling.
v2->v3:
 * Removed clock patch#1 as it is queued for 6.3 renesas-clk
 * Added Rb tag from Geert for bindings and dt patches
 * Added return code for rzv2m_pwm_get_state()
 * Added comment in rzv2m_pwm_reset_assert_pm_disable()
v1->v2:
 * Updated commit description
 * Replaced pwm8_15_pclk->cperi_grpf
 * Added reset entry R9A09G011_PWM_GPF_PRESETN
 * Added Rb tag from Krzysztof for bindings and the keep the Rb tag as
   the below changes are trivial
 * Updated the description for APB clock
 * Added resets required property
 * Updated the example with resets property
 * Replaced
   devm_reset_control_get_optional_shared->devm_reset_control_get_shared
 * Added resets property in pwm nodes.

Biju Das (4):
  dt-bindings: pwm: Add RZ/V2M PWM binding
  pwm: Add support for RZ/V2M PWM driver
  arm64: dts: renesas: r9a09g011: Add pwm nodes
  arm64: dts: renesas: rzv2m evk: Enable pwm

 .../bindings/pwm/renesas,rzv2m-pwm.yaml       |  90 ++++
 .../boot/dts/renesas/r9a09g011-v2mevk2.dts    |  70 +++
 arch/arm64/boot/dts/renesas/r9a09g011.dtsi    |  98 ++++
 drivers/pwm/Kconfig                           |  11 +
 drivers/pwm/Makefile                          |   1 +
 drivers/pwm/pwm-rzv2m.c                       | 480 ++++++++++++++++++
 6 files changed, 750 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/renesas,rzv2m-pwm.yaml
 create mode 100644 drivers/pwm/pwm-rzv2m.c