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![Guru Das Srinagesh](/assets/img/avatar_default.png)
Since the PWM framework is switching struct pwm_state.period's datatype to u64, prepare for this transition by using nsecs_to_jiffies() which does away with the need for a division operation. Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org> Acked-by: Chen-Yu Tsai <wens@csie.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
533 lines
13 KiB
C
533 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Driver for Allwinner sun4i Pulse Width Modulation Controller
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*
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* Copyright (C) 2014 Alexandre Belloni <alexandre.belloni@free-electrons.com>
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*
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* Limitations:
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* - When outputing the source clock directly, the PWM logic will be bypassed
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* and the currently running period is not guaranteed to be completed
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*/
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#include <linux/bitops.h>
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/jiffies.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/pwm.h>
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#include <linux/reset.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/time.h>
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#define PWM_CTRL_REG 0x0
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#define PWM_CH_PRD_BASE 0x4
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#define PWM_CH_PRD_OFFSET 0x4
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#define PWM_CH_PRD(ch) (PWM_CH_PRD_BASE + PWM_CH_PRD_OFFSET * (ch))
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#define PWMCH_OFFSET 15
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#define PWM_PRESCAL_MASK GENMASK(3, 0)
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#define PWM_PRESCAL_OFF 0
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#define PWM_EN BIT(4)
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#define PWM_ACT_STATE BIT(5)
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#define PWM_CLK_GATING BIT(6)
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#define PWM_MODE BIT(7)
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#define PWM_PULSE BIT(8)
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#define PWM_BYPASS BIT(9)
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#define PWM_RDY_BASE 28
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#define PWM_RDY_OFFSET 1
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#define PWM_RDY(ch) BIT(PWM_RDY_BASE + PWM_RDY_OFFSET * (ch))
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#define PWM_PRD(prd) (((prd) - 1) << 16)
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#define PWM_PRD_MASK GENMASK(15, 0)
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#define PWM_DTY_MASK GENMASK(15, 0)
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#define PWM_REG_PRD(reg) ((((reg) >> 16) & PWM_PRD_MASK) + 1)
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#define PWM_REG_DTY(reg) ((reg) & PWM_DTY_MASK)
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#define PWM_REG_PRESCAL(reg, chan) (((reg) >> ((chan) * PWMCH_OFFSET)) & PWM_PRESCAL_MASK)
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#define BIT_CH(bit, chan) ((bit) << ((chan) * PWMCH_OFFSET))
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static const u32 prescaler_table[] = {
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120,
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180,
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240,
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360,
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480,
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0,
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0,
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0,
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12000,
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24000,
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36000,
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48000,
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72000,
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0,
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0,
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0, /* Actually 1 but tested separately */
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};
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struct sun4i_pwm_data {
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bool has_prescaler_bypass;
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bool has_direct_mod_clk_output;
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unsigned int npwm;
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};
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struct sun4i_pwm_chip {
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struct pwm_chip chip;
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struct clk *bus_clk;
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struct clk *clk;
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struct reset_control *rst;
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void __iomem *base;
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spinlock_t ctrl_lock;
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const struct sun4i_pwm_data *data;
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unsigned long next_period[2];
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};
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static inline struct sun4i_pwm_chip *to_sun4i_pwm_chip(struct pwm_chip *chip)
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{
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return container_of(chip, struct sun4i_pwm_chip, chip);
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}
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static inline u32 sun4i_pwm_readl(struct sun4i_pwm_chip *chip,
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unsigned long offset)
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{
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return readl(chip->base + offset);
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}
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static inline void sun4i_pwm_writel(struct sun4i_pwm_chip *chip,
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u32 val, unsigned long offset)
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{
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writel(val, chip->base + offset);
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}
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static void sun4i_pwm_get_state(struct pwm_chip *chip,
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struct pwm_device *pwm,
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struct pwm_state *state)
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{
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struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
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u64 clk_rate, tmp;
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u32 val;
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unsigned int prescaler;
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clk_rate = clk_get_rate(sun4i_pwm->clk);
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val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
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/*
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* PWM chapter in H6 manual has a diagram which explains that if bypass
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* bit is set, no other setting has any meaning. Even more, experiment
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* proved that also enable bit is ignored in this case.
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*/
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if ((val & BIT_CH(PWM_BYPASS, pwm->hwpwm)) &&
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sun4i_pwm->data->has_direct_mod_clk_output) {
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state->period = DIV_ROUND_UP_ULL(NSEC_PER_SEC, clk_rate);
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state->duty_cycle = DIV_ROUND_UP_ULL(state->period, 2);
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state->polarity = PWM_POLARITY_NORMAL;
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state->enabled = true;
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return;
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}
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if ((PWM_REG_PRESCAL(val, pwm->hwpwm) == PWM_PRESCAL_MASK) &&
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sun4i_pwm->data->has_prescaler_bypass)
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prescaler = 1;
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else
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prescaler = prescaler_table[PWM_REG_PRESCAL(val, pwm->hwpwm)];
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if (prescaler == 0)
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return;
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if (val & BIT_CH(PWM_ACT_STATE, pwm->hwpwm))
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state->polarity = PWM_POLARITY_NORMAL;
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else
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state->polarity = PWM_POLARITY_INVERSED;
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if ((val & BIT_CH(PWM_CLK_GATING | PWM_EN, pwm->hwpwm)) ==
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BIT_CH(PWM_CLK_GATING | PWM_EN, pwm->hwpwm))
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state->enabled = true;
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else
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state->enabled = false;
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val = sun4i_pwm_readl(sun4i_pwm, PWM_CH_PRD(pwm->hwpwm));
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tmp = (u64)prescaler * NSEC_PER_SEC * PWM_REG_DTY(val);
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state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
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tmp = (u64)prescaler * NSEC_PER_SEC * PWM_REG_PRD(val);
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state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
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}
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static int sun4i_pwm_calculate(struct sun4i_pwm_chip *sun4i_pwm,
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const struct pwm_state *state,
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u32 *dty, u32 *prd, unsigned int *prsclr,
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bool *bypass)
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{
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u64 clk_rate, div = 0;
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unsigned int prescaler = 0;
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clk_rate = clk_get_rate(sun4i_pwm->clk);
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*bypass = sun4i_pwm->data->has_direct_mod_clk_output &&
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state->enabled &&
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(state->period * clk_rate >= NSEC_PER_SEC) &&
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(state->period * clk_rate < 2 * NSEC_PER_SEC) &&
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(state->duty_cycle * clk_rate * 2 >= NSEC_PER_SEC);
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/* Skip calculation of other parameters if we bypass them */
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if (*bypass)
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return 0;
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if (sun4i_pwm->data->has_prescaler_bypass) {
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/* First, test without any prescaler when available */
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prescaler = PWM_PRESCAL_MASK;
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/*
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* When not using any prescaler, the clock period in nanoseconds
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* is not an integer so round it half up instead of
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* truncating to get less surprising values.
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*/
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div = clk_rate * state->period + NSEC_PER_SEC / 2;
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do_div(div, NSEC_PER_SEC);
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if (div - 1 > PWM_PRD_MASK)
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prescaler = 0;
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}
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if (prescaler == 0) {
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/* Go up from the first divider */
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for (prescaler = 0; prescaler < PWM_PRESCAL_MASK; prescaler++) {
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unsigned int pval = prescaler_table[prescaler];
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if (!pval)
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continue;
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div = clk_rate;
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do_div(div, pval);
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div = div * state->period;
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do_div(div, NSEC_PER_SEC);
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if (div - 1 <= PWM_PRD_MASK)
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break;
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}
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if (div - 1 > PWM_PRD_MASK)
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return -EINVAL;
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}
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*prd = div;
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div *= state->duty_cycle;
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do_div(div, state->period);
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*dty = div;
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*prsclr = prescaler;
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return 0;
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}
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static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
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const struct pwm_state *state)
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{
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struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
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struct pwm_state cstate;
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u32 ctrl, duty = 0, period = 0, val;
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int ret;
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unsigned int delay_us, prescaler = 0;
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unsigned long now;
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bool bypass;
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pwm_get_state(pwm, &cstate);
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if (!cstate.enabled) {
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ret = clk_prepare_enable(sun4i_pwm->clk);
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if (ret) {
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dev_err(chip->dev, "failed to enable PWM clock\n");
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return ret;
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}
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}
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ret = sun4i_pwm_calculate(sun4i_pwm, state, &duty, &period, &prescaler,
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&bypass);
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if (ret) {
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dev_err(chip->dev, "period exceeds the maximum value\n");
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if (!cstate.enabled)
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clk_disable_unprepare(sun4i_pwm->clk);
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return ret;
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}
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spin_lock(&sun4i_pwm->ctrl_lock);
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ctrl = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
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if (sun4i_pwm->data->has_direct_mod_clk_output) {
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if (bypass) {
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ctrl |= BIT_CH(PWM_BYPASS, pwm->hwpwm);
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/* We can skip other parameter */
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sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
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spin_unlock(&sun4i_pwm->ctrl_lock);
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return 0;
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}
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ctrl &= ~BIT_CH(PWM_BYPASS, pwm->hwpwm);
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}
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if (PWM_REG_PRESCAL(ctrl, pwm->hwpwm) != prescaler) {
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/* Prescaler changed, the clock has to be gated */
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ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
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sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
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ctrl &= ~BIT_CH(PWM_PRESCAL_MASK, pwm->hwpwm);
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ctrl |= BIT_CH(prescaler, pwm->hwpwm);
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}
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val = (duty & PWM_DTY_MASK) | PWM_PRD(period);
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sun4i_pwm_writel(sun4i_pwm, val, PWM_CH_PRD(pwm->hwpwm));
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sun4i_pwm->next_period[pwm->hwpwm] = jiffies +
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nsecs_to_jiffies(cstate.period + 1000);
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if (state->polarity != PWM_POLARITY_NORMAL)
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ctrl &= ~BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
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else
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ctrl |= BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
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ctrl |= BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
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if (state->enabled) {
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ctrl |= BIT_CH(PWM_EN, pwm->hwpwm);
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} else {
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ctrl &= ~BIT_CH(PWM_EN, pwm->hwpwm);
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ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
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}
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sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
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spin_unlock(&sun4i_pwm->ctrl_lock);
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if (state->enabled)
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return 0;
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/* We need a full period to elapse before disabling the channel. */
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now = jiffies;
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if (time_before(now, sun4i_pwm->next_period[pwm->hwpwm])) {
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delay_us = jiffies_to_usecs(sun4i_pwm->next_period[pwm->hwpwm] -
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now);
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if ((delay_us / 500) > MAX_UDELAY_MS)
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msleep(delay_us / 1000 + 1);
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else
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usleep_range(delay_us, delay_us * 2);
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}
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spin_lock(&sun4i_pwm->ctrl_lock);
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ctrl = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
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ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
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ctrl &= ~BIT_CH(PWM_EN, pwm->hwpwm);
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sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
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spin_unlock(&sun4i_pwm->ctrl_lock);
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clk_disable_unprepare(sun4i_pwm->clk);
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return 0;
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}
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static const struct pwm_ops sun4i_pwm_ops = {
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.apply = sun4i_pwm_apply,
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.get_state = sun4i_pwm_get_state,
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.owner = THIS_MODULE,
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};
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static const struct sun4i_pwm_data sun4i_pwm_dual_nobypass = {
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.has_prescaler_bypass = false,
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.npwm = 2,
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};
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static const struct sun4i_pwm_data sun4i_pwm_dual_bypass = {
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.has_prescaler_bypass = true,
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.npwm = 2,
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};
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static const struct sun4i_pwm_data sun4i_pwm_single_bypass = {
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.has_prescaler_bypass = true,
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.npwm = 1,
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};
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static const struct sun4i_pwm_data sun50i_a64_pwm_data = {
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.has_prescaler_bypass = true,
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.has_direct_mod_clk_output = true,
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.npwm = 1,
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};
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static const struct sun4i_pwm_data sun50i_h6_pwm_data = {
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.has_prescaler_bypass = true,
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.has_direct_mod_clk_output = true,
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.npwm = 2,
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};
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static const struct of_device_id sun4i_pwm_dt_ids[] = {
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{
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.compatible = "allwinner,sun4i-a10-pwm",
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.data = &sun4i_pwm_dual_nobypass,
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}, {
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.compatible = "allwinner,sun5i-a10s-pwm",
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.data = &sun4i_pwm_dual_bypass,
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}, {
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.compatible = "allwinner,sun5i-a13-pwm",
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.data = &sun4i_pwm_single_bypass,
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}, {
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.compatible = "allwinner,sun7i-a20-pwm",
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.data = &sun4i_pwm_dual_bypass,
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}, {
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.compatible = "allwinner,sun8i-h3-pwm",
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.data = &sun4i_pwm_single_bypass,
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}, {
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.compatible = "allwinner,sun50i-a64-pwm",
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.data = &sun50i_a64_pwm_data,
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}, {
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.compatible = "allwinner,sun50i-h6-pwm",
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.data = &sun50i_h6_pwm_data,
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}, {
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/* sentinel */
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},
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};
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MODULE_DEVICE_TABLE(of, sun4i_pwm_dt_ids);
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static int sun4i_pwm_probe(struct platform_device *pdev)
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{
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struct sun4i_pwm_chip *pwm;
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struct resource *res;
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int ret;
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pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
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if (!pwm)
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return -ENOMEM;
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pwm->data = of_device_get_match_data(&pdev->dev);
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if (!pwm->data)
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return -ENODEV;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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pwm->base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(pwm->base))
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return PTR_ERR(pwm->base);
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/*
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* All hardware variants need a source clock that is divided and
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* then feeds the counter that defines the output wave form. In the
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* device tree this clock is either unnamed or called "mod".
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* Some variants (e.g. H6) need another clock to access the
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* hardware registers; this is called "bus".
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* So we request "mod" first (and ignore the corner case that a
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* parent provides a "mod" clock while the right one would be the
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* unnamed one of the PWM device) and if this is not found we fall
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* back to the first clock of the PWM.
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*/
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pwm->clk = devm_clk_get_optional(&pdev->dev, "mod");
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if (IS_ERR(pwm->clk)) {
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if (PTR_ERR(pwm->clk) != -EPROBE_DEFER)
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dev_err(&pdev->dev, "get mod clock failed %pe\n",
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pwm->clk);
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return PTR_ERR(pwm->clk);
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}
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if (!pwm->clk) {
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pwm->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(pwm->clk)) {
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if (PTR_ERR(pwm->clk) != -EPROBE_DEFER)
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dev_err(&pdev->dev, "get unnamed clock failed %pe\n",
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pwm->clk);
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return PTR_ERR(pwm->clk);
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}
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}
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pwm->bus_clk = devm_clk_get_optional(&pdev->dev, "bus");
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if (IS_ERR(pwm->bus_clk)) {
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if (PTR_ERR(pwm->bus_clk) != -EPROBE_DEFER)
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dev_err(&pdev->dev, "get bus clock failed %pe\n",
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pwm->bus_clk);
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return PTR_ERR(pwm->bus_clk);
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}
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pwm->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
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if (IS_ERR(pwm->rst)) {
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if (PTR_ERR(pwm->rst) != -EPROBE_DEFER)
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dev_err(&pdev->dev, "get reset failed %pe\n",
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pwm->rst);
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return PTR_ERR(pwm->rst);
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|
}
|
|
|
|
/* Deassert reset */
|
|
ret = reset_control_deassert(pwm->rst);
|
|
if (ret) {
|
|
dev_err(&pdev->dev, "cannot deassert reset control: %pe\n",
|
|
ERR_PTR(ret));
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* We're keeping the bus clock on for the sake of simplicity.
|
|
* Actually it only needs to be on for hardware register accesses.
|
|
*/
|
|
ret = clk_prepare_enable(pwm->bus_clk);
|
|
if (ret) {
|
|
dev_err(&pdev->dev, "cannot prepare and enable bus_clk %pe\n",
|
|
ERR_PTR(ret));
|
|
goto err_bus;
|
|
}
|
|
|
|
pwm->chip.dev = &pdev->dev;
|
|
pwm->chip.ops = &sun4i_pwm_ops;
|
|
pwm->chip.base = -1;
|
|
pwm->chip.npwm = pwm->data->npwm;
|
|
pwm->chip.of_xlate = of_pwm_xlate_with_flags;
|
|
pwm->chip.of_pwm_n_cells = 3;
|
|
|
|
spin_lock_init(&pwm->ctrl_lock);
|
|
|
|
ret = pwmchip_add(&pwm->chip);
|
|
if (ret < 0) {
|
|
dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
|
|
goto err_pwm_add;
|
|
}
|
|
|
|
platform_set_drvdata(pdev, pwm);
|
|
|
|
return 0;
|
|
|
|
err_pwm_add:
|
|
clk_disable_unprepare(pwm->bus_clk);
|
|
err_bus:
|
|
reset_control_assert(pwm->rst);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int sun4i_pwm_remove(struct platform_device *pdev)
|
|
{
|
|
struct sun4i_pwm_chip *pwm = platform_get_drvdata(pdev);
|
|
int ret;
|
|
|
|
ret = pwmchip_remove(&pwm->chip);
|
|
if (ret)
|
|
return ret;
|
|
|
|
clk_disable_unprepare(pwm->bus_clk);
|
|
reset_control_assert(pwm->rst);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct platform_driver sun4i_pwm_driver = {
|
|
.driver = {
|
|
.name = "sun4i-pwm",
|
|
.of_match_table = sun4i_pwm_dt_ids,
|
|
},
|
|
.probe = sun4i_pwm_probe,
|
|
.remove = sun4i_pwm_remove,
|
|
};
|
|
module_platform_driver(sun4i_pwm_driver);
|
|
|
|
MODULE_ALIAS("platform:sun4i-pwm");
|
|
MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
|
|
MODULE_DESCRIPTION("Allwinner sun4i PWM driver");
|
|
MODULE_LICENSE("GPL v2");
|