RE: [PATCH v12 0/2] Add support for RZ/G2L GPT

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Hi Thierry, Uwe, Geert and PWM folks,

Gentle ping for review. 

Cheers,
Biju

> Subject: [PATCH v12 0/2] Add support for RZ/G2L GPT
> 
> RZ/G2L General PWM Timer (GPT) composed of 8 channels with 32-bit timer
> (GPT32E). It supports the following functions
>  * 32 bits × 8 channels
>  * Up-counting or down-counting (saw waves) or up/down-counting
>    (triangle waves) for each counter.
>  * Clock sources independently selectable for each channel
>  * Two I/O pins per channel
>  * Two output compare/input capture registers per channel
>  * For the two output compare/input capture registers of each channel,
>    four registers are provided as buffer registers and are capable of
>    operating as comparison registers when buffering is not in use.
>  * In output compare operation, buffer switching can be at crests or
>    troughs, enabling the generation of laterally asymmetric PWM waveforms.
>  * Registers for setting up frame cycles in each channel (with capability
>    for generating interrupts at overflow or underflow)
>  * Generation of dead times in PWM operation
>  * Synchronous starting, stopping and clearing counters for arbitrary
>    channels
>  * Starting, stopping, clearing and up/down counters in response to input
>    level comparison
>  * Starting, clearing, stopping and up/down counters in response to a
>    maximum of four external triggers
>  * Output pin disable function by dead time error and detected
>    short-circuits between output pins
>  * A/D converter start triggers can be generated (GPT32E0 to GPT32E3)
>  * Enables the noise filter for input capture and external trigger
>    operation
> 
> This patch series aims to add basic pwm support for RZ/G2L GPT driver by
> creating separate logical channels for each IOs.
> 
> v11->v12:
>  * Added return code for get_state()
>  * Cache duty cycle/prescale as the driver cannot read the current duty
>    cycle/prescale from the hardware if the hardware is disabled. Cache the
>    last programmed duty cycle/prescale value to return in that case.
>  * Updated rzg2l_gpt_enable to enable the clocks.
>  * Updated rzg2l_gpt_disable to disable the clocks.
>  * Updated rzg2l_gpt_config() to cache duty cucle/prescale value
>  * Updated rzg2l_gpt_get_state to use cached value of duty cycle/prescale,If
> the PWM
>    is disabled.
>  * Simplified rzg2l_gpt_apply()
>  * Added comments in rzg2l_gpt_reset_assert_pm_disable()
> v10->v11:
>  * Used bitmap_zero for initializing bitmap varable.
>  * Fixed clock imbalance during remove for the case bootloader turning
>    on PWM and module unload is called just after the boot.
>  * Fixed over flow condition in get_state() for a prescale value of 2 &
> more.
>  * Improved rzg2l_gpt_cntr_need_stop() based on prescale as it is the
>    only runtime variable.
>  * Added array for Cache variables state_period and prescale
>  * Probe caches the prescale value set by the bootloader.
>  * Updated rzg2l_gpt_config() to make use of array variables.
> v9->v10:
>  * Updated the example gpt4: pwm@10048400-> gpt: pwm@10048000
>  * Keep Rb tag from Rob as the above change is trivial one.
>  * Updated the error handling in probe(), clk_disable_unprepare called
>    on the error path.
>  * Removed ch_en array and started using bitmask instead.
> v8->v9:
>  * Added Rb tag from Rob.
>  * deassert after devm_clk_get() to avoid reset stays deasserted,in case
>    clk_get() fails.
>  * Removed ch_offs from struct rzg2l_gpt_chip and use macro instead.
>  * Updated error handling in probe()
> v7->v8:
>  * Removed Rb tags from Rob and Geert as it modelled as single GPT
>    device handling multiple channels.
>  * Updated description
>  * Updated interrupts and interrupt-names properties
>  * Updated binding example
>  * Modelled as single PWM device handling multiple channels
>  * Replaced shared reset->devm_reset_control_get_exclusive()
>  * Added PM runtime callbacks
>  * Updated PM handling and removed "pwm_enabled_by_bootloader" variable
>  * Replaced iowrite32->writel and ioread32->readl
>  * Updated prescale calculation
>  * Introduced rzg2l_gpt_is_ch_enabled for checking enable status on both
>    IO's
>  * Moved enable/disable output pins from config->enable/disable.
>  * Added rzg2l_gpt_cntr_need_stop() for caching prescalar/mode values.
> v6->v7:
>  * Added the comment for cacheing rzg2l_gpt->state_period.
>  * Fixed boundary values for pv and dc.
>  * Added comment for modifying mode, prescaler, timer counter and buffer
> enable
>    registers.
>  * Fixed buffer overflow in get_state()
>  * Removed unnecessary assignment of state->period value in get_state().
>  * Fixed state->duty_cycle value in get_state().
>  * Added a limitation for disabling the channels, when both channels used
> v5->v6:
>  * Updated macros RZG2L_GTIOR_GTIOB_OUT_HI_END_TOGGLE_CMP_MATCH and
>    RZG2L_GTIOR_GTIOB_OUT_LO_END_TOGGLE_CMP_MATCH with computation
>    involving FIELD_PREP macro.
>  * Removed struct rzg2l_gpt_phase and started using RZG2L_GTCCR macro
>    for duty_offset.
>  * replaced misnomer real_period->state_period.
>  * Added handling for values >= (1024 << 32) for both period
>    and duty cycle.
>  * Added comments for pwm {en,dis}abled by bootloader during probe.
> v4->v5:
>  * Added Hardware manual details
>  * Replaced the comment GTCNT->Counter
>  * Removed the macros RZG2L_GPT_IO_PER_CHANNEL and chip.npwm directly
>    used in probe.
>  * Removed the unsed macro RZG2L_GTPR_MAX_VALUE
>  * Added driver prefix for the type name and the variable.
>  * Initialization of per_channel data moved from request->probe.
>  * Updated clr parameter for rzg2l_gpt_modify for Start count.
>  * Started using mutex and usage_count for handling shared
>    period and prescalar for the 2 channels.
>  * Updated the comment cycle->period.
>  * Removed clk_disable from rzg2l_gpt_reset_assert_pm_disable()
>  * Replaced pc->rzg2l_gpt.
>  * Updated prescale calculation.
>  * Moved pm_runtime_{get_sync,put} from {request,free}->{enable,disable}
>  * Removed platform_set_drvdata as it is unused
>  * Removed the variable pwm_enabled_by_bootloader
>  * Added dev_err_probe in various probe error path.
>  * Added an error message, if devm_pwmchip_add fails.
> v3->v4:
>  * Changed the local variable type i from u16->u8 and prescaled_period_
>    cycles from u64->u32 in calculate_prescale().
>  * Replaced mul_u64_u64_div_u64()->mul_u64_u32_div()
>  * Dropped the comma after the sentinel.
>  * Add a variable to track pwm enabled by bootloader and added comments
>    in probe().
>  * Removed unnecessary rzg2l_gpt_reset_assert_pm_disable() from probe.
>  * Replaced devm_clk_get()->devm_clk_get_prepared()
>  * Removed devm_clk_get_optional_enabled()
> v2->v3:
>  * Added Rb tag from Rob for the bindings.
>  * Updated limitation section
>  * Added prefix "RZG2L_" for all macros
>  * Modified prescale calculation
>  * Removed pwm_set_chip_data
>  * Updated comment related to modifying Mode and Prescaler
>  * Updated setting of prescale value in rzg2l_gpt_config()
>  * Removed else branch from rzg2l_gpt_get_state()
>  * removed the err label from rzg2l_gpt_apply()
>  * Added devm_clk_get_optional_enabled() to retain clk on status,
>    in case bootloader turns on the clk of pwm.
>  * Replaced devm_reset_control_get_exclusive->devm_reset_control_get_shared
>    as single reset shared between 8 channels.
> V1->v2:
>  * Added '|' after 'description:' to preserve formatting.
>  * Removed description for pwm_cells as it is common property.
>  * Changed the reg size in example from 0xa4->0x100
>  * Added Rb tag from Geert for bindings.
>  * Added Limitations section
>  * dropped "_MASK" from the define names.
>  * used named initializer for struct phase
>  * Added gpt_pwm_device into a flexible array member in rzg2l_gpt_chip
>  * Revised the logic for prescale
>  * Added .get_state callback
>  * Improved error handling in rzg2l_gpt_apply
>  * Removed .remove callback
>  * Tested the driver with PWM_DEBUG enabled.
> 
> RFC->v1:
>  * Added Description in binding patch
>  * Removed comments from reg and clock
>  * replaced rzg2l_gpt_write_mask()->rzg2l_gpt_modify()
>  * Added rzg2l_gpt_read() and updated macros
>  * Removed dtsi patches, will send it separately
> 
> RFC:
>  *
> https://jpn01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kerne
> l.org%2Flinux-renesas-soc%2F20220430075915.5036-1-
> biju.das.jz%40bp.renesas.com%2FT%2F%23t&data=05%7C01%7Cbiju.das.jz%40bp.rene
> sas.com%7C7c8baf2b02984371f2c308daddd64607%7C53d82571da1947e49cb4625a166a4a2
> a%7C0%7C0%7C638066209617005815%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiL
> CJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=UmYbVZnI
> qFciTNH2VvVMviGWZrNNLu412C2yhzt%2FnkA%3D&reserved=0
> 
> Biju Das (2):
>   dt-bindings: pwm: Add RZ/G2L GPT binding
>   pwm: Add support for RZ/G2L GPT
> 
>  .../bindings/pwm/renesas,rzg2l-gpt.yaml       | 378 ++++++++++++
>  drivers/pwm/Kconfig                           |  11 +
>  drivers/pwm/Makefile                          |   1 +
>  drivers/pwm/pwm-rzg2l-gpt.c                   | 570 ++++++++++++++++++
>  4 files changed, 960 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pwm/renesas,rzg2l-
> gpt.yaml
>  create mode 100644 drivers/pwm/pwm-rzg2l-gpt.c
> 
> --
> 2.25.1





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