lwn.git/drivers/pwm, branch docs-6.4-2

pwm: dwc: Use devm_pwmchip_add()

2023-02-20T11:26:35+00:00

Add the PWM chip using devm_pwmchip_add() to avoid having to manually remove it. This is useful for subsequent patches adding platform device support. Signed-off-by: Ben Dooks Reviewed-by: Uwe Kleine-König Signed-off-by: Thierry Reding

pwm: dwc: Move memory allocation to own function

2023-02-20T11:26:34+00:00

In preparation for adding other bus support, move the allocation of the PWM structure out of the main driver code. Signed-off-by: Ben Dooks Acked-by: Uwe Kleine-König Signed-off-by: Thierry Reding

pwm: dwc: Change &pci->dev to dev in probe

2023-02-20T11:26:04+00:00

The dwc_pwm_probe() assigns dev to be &pci->dev but then uses &pci->dev throughout the function. Change these all to the 'dev' variable to make lines shorter. Signed-off-by: Ben Dooks Acked-by: Uwe Kleine-König Signed-off-by: Thierry Reding

pwm: iqs620a: Replace one remaining instance of regmap_update_bits()

2023-02-17T15:02:19+00:00

The call to regmap_update_bits() which was responsible for clearing the PWM output enable register bit was recently dropped in favor of a call to regmap_clear_bits(), thereby simplifying the code. Similarly, the call to regmap_update_bits() which sets the same bit can be simplified with a call to regmap_set_bits(). Signed-off-by: Jeff LaBundy Reviewed-by: Uwe Kleine-König Signed-off-by: Thierry Reding

pwm: ab8500: Implement .get_state()

2023-02-17T14:59:52+00:00

The registers are readable, so it's possible to implement the .get_state() callback for this PWM. Signed-off-by: Uwe Kleine-König Signed-off-by: Thierry Reding

pwm: ab8500: Fix calculation of duty and period

2023-02-17T14:59:51+00:00

After a check of the manual it becomes obvious that the calculations in .apply() are totally bogus: FreqPWMOutx was always written as zero, so the period was fixed at 3413333.33 ns. However state->period wasn't checked at all. The lower 10 bits of duty_cycle were just used as DutyPWMOutx. So if a duty cycle of 512 ns (or 1536 ns) was requested, it actually programmed 1710000 ns. Other values were wrong by the same factor. Signed-off-by: Uwe Kleine-König Signed-off-by: Thierry Reding

pwm: lp3943: Drop unused i2c include

2023-01-30T16:20:30+00:00

lp3943 is a platform driver that doesn't use any symbol provided in . So drop the include. Signed-off-by: Uwe Kleine-König Signed-off-by: Thierry Reding

pwm: stm32-lp: fix the check on arr and cmp registers update

2023-01-30T15:42:45+00:00

The ARR (auto reload register) and CMP (compare) registers are successively written. The status bits to check the update of these registers are polled together with regmap_read_poll_timeout(). The condition to end the loop may become true, even if one of the register isn't correctly updated. So ensure both status bits are set before clearing them. Fixes: e70a540b4e02 ("pwm: Add STM32 LPTimer PWM driver") Signed-off-by: Fabrice Gasnier Acked-by: Uwe Kleine-König Signed-off-by: Thierry Reding

pwm: sifive: Always let the first pwm_apply_state succeed

2023-01-30T15:42:45+00:00

Commit 2cfe9bbec56ea579135cdd92409fff371841904f added support for the RGB and green PWM controlled LEDs on the HiFive Unmatched board managed by the leds-pwm-multicolor and leds-pwm drivers respectively. All three colours of the RGB LED and the green LED run from different lines of the same PWM, but with the same period so this works fine when the LED drivers are loaded one after the other. Unfortunately it does expose a race in the PWM driver when both LED drivers are loaded at roughly the same time. Here is an example: | Thread A | Thread B | | led_pwm_mc_probe | led_pwm_probe | | devm_fwnode_pwm_get | | | pwm_sifive_request | | | ddata->user_count++ | | | | devm_fwnode_pwm_get | | | pwm_sifive_request | | | ddata->user_count++ | | ... | ... | | pwm_state_apply | pwm_state_apply | | pwm_sifive_apply | pwm_sifive_apply | Now both calls to pwm_sifive_apply will see that ddata->approx_period, initially 0, is different from the requested period and the clock needs to be updated. But since ddata->user_count >= 2 both calls will fail with -EBUSY, which will then cause both LED drivers to fail to probe. Fix it by letting the first call to pwm_sifive_apply update the clock even when ddata->user_count != 1. Fixes: 9e37a53eb051 ("pwm: sifive: Add a driver for SiFive SoC PWM") Signed-off-by: Emil Renner Berthing Signed-off-by: Thierry Reding

Merge tag 'pwm/for-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

2022-12-21T17:41:28+00:00

Pull pwm updates from Thierry Reding: "Various changes across the board, mostly improvements and cleanups" * tag 'pwm/for-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (42 commits) pwm: pca9685: Convert to i2c's .probe_new() pwm: sun4i: Propagate errors in .get_state() to the caller pwm: Handle .get_state() failures pwm: sprd: Propagate errors in .get_state() to the caller pwm: rockchip: Propagate errors in .get_state() to the caller pwm: mtk-disp: Propagate errors in .get_state() to the caller pwm: imx27: Propagate errors in .get_state() to the caller pwm: cros-ec: Propagate errors in .get_state() to the caller pwm: crc: Propagate errors in .get_state() to the caller leds: qcom-lpg: Propagate errors in .get_state() to the caller drm/bridge: ti-sn65dsi86: Propagate errors in .get_state() to the caller pwm/tracing: Also record trace events for failed API calls pwm: Make .get_state() callback return an error code pwm: pxa: Enable for MMP platform pwm: pxa: Add reference manual link and limitations pwm: pxa: Use abrupt shutdown mode pwm: pxa: Remove clk enable/disable from pxa_pwm_config pwm: pxa: Set duty cycle to 0 when disabling PWM pwm: pxa: Remove pxa_pwm_enable/disable pwm: mediatek: Add support for MT7986 ...