1 // SPDX-License-Identifier: GPL-2.0
5 //! Rust T-HEAD TH1520 PWM driver
8 //! - The period and duty cycle are controlled by 32-bit hardware registers,
10 //! - The driver supports continuous output mode only; one-shot mode is not
12 //! - The controller hardware provides up to 6 PWM channels.
13 //! - Reconfiguration is glitch free - new period and duty cycle values are
15 //! - Polarity is handled via a simple hardware inversion bit; arbitrary
17 //! - Disabling a channel is achieved by configuring its duty cycle to zero to
32     pwm, time,
38 const fn th1520_pwm_chn_base(n: u32) -> usize {  in th1520_pwm_chn_base()
42 const fn th1520_pwm_ctrl(n: u32) -> usize {  in th1520_pwm_ctrl()
46 const fn th1520_pwm_per(n: u32) -> usize {  in th1520_pwm_per()
50 const fn th1520_pwm_fp(n: u32) -> usize {  in th1520_pwm_fp()
62 fn ns_to_cycles(ns: u64, rate_hz: u64) -> u64 {  in ns_to_cycles()
71 fn cycles_to_ns(cycles: u64, rate_hz: u64) -> u64 {  in cycles_to_ns()
78         .saturating_add(rate_hz - 1);  in cycles_to_ns()
83 /// Hardware-specific waveform representation for TH1520.
106 // We can guarantee this because the PWM core synchronizes all callbacks, preventing concurrent
110 // SAFETY: The same reasoning applies as for `Send`. The PWM core's synchronization
115 impl pwm::PwmOps for Th1520PwmDriverData {
119         chip: &pwm::Chip<Self>,  in round_waveform_tohw()
120         _pwm: &pwm::Device,  in round_waveform_tohw()
121         wf: &pwm::Waveform,  in round_waveform_tohw()
122     ) -> Result<pwm::RoundedWaveform<Self::WfHw>> {  in round_waveform_tohw()
127             dev_dbg!(chip.device(), "Requested period is 0, disabling PWM.\n");  in round_waveform_tohw()
129             return Ok(pwm::RoundedWaveform {  in round_waveform_tohw()
162             duty_cycles = period_cycles - duty_cycles;  in round_waveform_tohw()
177             "Requested: {}/{} ns [+{} ns] -> HW: {}/{} cycles, ctrl 0x{:x}, rate {} Hz\n",  in round_waveform_tohw()
187         Ok(pwm::RoundedWaveform {  in round_waveform_tohw()
194         chip: &pwm::Chip<Self>,  in round_waveform_fromhw()
195         _pwm: &pwm::Device,  in round_waveform_fromhw()
197         wf: &mut pwm::Waveform,  in round_waveform_fromhw()
198     ) -> Result {  in round_waveform_fromhw()
207             *wf = pwm::Waveform::default();  in round_waveform_fromhw()
222             // For an inverted signal, `duty_length_ns` is the high time (period - low_time).  in round_waveform_fromhw()
232         chip: &pwm::Chip<Self>,  in read_waveform()
233         pwm: &pwm::Device,  in read_waveform()
235     ) -> Result<Self::WfHw> {  in read_waveform()
237         let hwpwm = pwm.hwpwm();  in read_waveform()
254 …          "PWM-{}: read_waveform: Read hw state - period: {}, duty: {}, ctrl: 0x{:x}, enabled: {}",  in read_waveform()
266         chip: &pwm::Chip<Self>,  in write_waveform()
267         pwm: &pwm::Device,  in write_waveform()
270     ) -> Result {  in write_waveform()
272         let hwpwm = pwm.hwpwm();  in write_waveform()
279             dev_dbg!(chip.device(), "PWM-{}: Disabling channel.\n", hwpwm);  in write_waveform()
307             "PWM-{}: Wrote {}/{} cycles",  in write_waveform()
330     [(of::DeviceId::new(c_str!("thead,th1520-pwm")), ())]
340     ) -> impl PinInit<Self, Error> {  in probe()
366         let chip = pwm::Chip::new(  in probe()
370                 iomem <- request.iomap_sized::<TH1520_PWM_REG_SIZE>(),  in probe()
371                 clk <- clk,  in probe()
375         pwm::Registration::register(dev, chip)?;  in probe()
383     name: "pwm-th1520",
385     description: "T-HEAD TH1520 PWM driver",