From 37f7707077f5ea2515bf4b1dc7fad43f8e12993e Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Tue, 9 Jul 2024 12:18:05 +0200 Subject: pwm: atmel-tcb: Fix race condition and convert to guards MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The hardware only supports a single period length for both PWM outputs. So atmel_tcb_pwm_config() checks the configuration of the other output if it's compatible with the currently requested setting. The register values are then actually updated in atmel_tcb_pwm_enable(). To make this race free the lock must be held during the whole process, so grab the lock in .apply() instead of individually in atmel_tcb_pwm_disable() and atmel_tcb_pwm_enable() which then also covers atmel_tcb_pwm_config(). To simplify handling, use the guard helper to let the compiler care for unlocking. Otherwise unlocking would be more difficult as there is more than one exit path in atmel_tcb_pwm_apply(). Fixes: 9421bade0765 ("pwm: atmel: add Timer Counter Block PWM driver") Signed-off-by: Uwe Kleine-König Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20240709101806.52394-3-u.kleine-koenig@baylibre.com Signed-off-by: Uwe Kleine-König --- drivers/pwm/pwm-atmel-tcb.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'drivers/pwm/pwm-atmel-tcb.c') diff --git a/drivers/pwm/pwm-atmel-tcb.c b/drivers/pwm/pwm-atmel-tcb.c index 528e54c5999d..aca11493239a 100644 --- a/drivers/pwm/pwm-atmel-tcb.c +++ b/drivers/pwm/pwm-atmel-tcb.c @@ -81,7 +81,8 @@ static int atmel_tcb_pwm_request(struct pwm_chip *chip, tcbpwm->period = 0; tcbpwm->div = 0; - spin_lock(&tcbpwmc->lock); + guard(spinlock)(&tcbpwmc->lock); + regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), &cmr); /* * Get init config from Timer Counter registers if @@ -107,7 +108,6 @@ static int atmel_tcb_pwm_request(struct pwm_chip *chip, cmr |= ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO | ATMEL_TC_EEVT_XC0; regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), cmr); - spin_unlock(&tcbpwmc->lock); return 0; } @@ -137,7 +137,6 @@ static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm, if (tcbpwm->duty == 0) polarity = !polarity; - spin_lock(&tcbpwmc->lock); regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), &cmr); /* flush old setting and set the new one */ @@ -172,8 +171,6 @@ static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm, ATMEL_TC_SWTRG); tcbpwmc->bkup.enabled = 0; } - - spin_unlock(&tcbpwmc->lock); } static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm, @@ -194,7 +191,6 @@ static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm, if (tcbpwm->duty == 0) polarity = !polarity; - spin_lock(&tcbpwmc->lock); regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), &cmr); /* flush old setting and set the new one */ @@ -256,7 +252,6 @@ static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm, regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CCR), ATMEL_TC_SWTRG | ATMEL_TC_CLKEN); tcbpwmc->bkup.enabled = 1; - spin_unlock(&tcbpwmc->lock); return 0; } @@ -341,9 +336,12 @@ static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, static int atmel_tcb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, const struct pwm_state *state) { + struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); int duty_cycle, period; int ret; + guard(spinlock)(&tcbpwmc->lock); + if (!state->enabled) { atmel_tcb_pwm_disable(chip, pwm, state->polarity); return 0; -- cgit From c1330cb9a56d42632b1af54cda374e01e39dcc59 Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Tue, 9 Jul 2024 12:18:06 +0200 Subject: pwm: atmel-tcb: Simplify checking the companion output MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The two outputs provided by the supported hardware share some settings, so access to the other PWM is required when one of them is configured. Instead of an explicit if to deterimine the other PWM just use hwpwm ^ 1. Further atcbpwm is never NULL, so drop the corresponding check. Signed-off-by: Uwe Kleine-König Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20240709101806.52394-4-u.kleine-koenig@baylibre.com Signed-off-by: Uwe Kleine-König --- drivers/pwm/pwm-atmel-tcb.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) (limited to 'drivers/pwm/pwm-atmel-tcb.c') diff --git a/drivers/pwm/pwm-atmel-tcb.c b/drivers/pwm/pwm-atmel-tcb.c index aca11493239a..2feee3744b50 100644 --- a/drivers/pwm/pwm-atmel-tcb.c +++ b/drivers/pwm/pwm-atmel-tcb.c @@ -260,7 +260,8 @@ static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, { struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); struct atmel_tcb_pwm_device *tcbpwm = &tcbpwmc->pwms[pwm->hwpwm]; - struct atmel_tcb_pwm_device *atcbpwm = NULL; + /* companion PWM sharing register values period and div */ + struct atmel_tcb_pwm_device *atcbpwm = &tcbpwmc->pwms[pwm->hwpwm ^ 1]; int i = 0; int slowclk = 0; unsigned period; @@ -305,11 +306,6 @@ static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, duty = div_u64(duty_ns, min); period = div_u64(period_ns, min); - if (pwm->hwpwm == 0) - atcbpwm = &tcbpwmc->pwms[1]; - else - atcbpwm = &tcbpwmc->pwms[0]; - /* * PWM devices provided by the TCB driver are grouped by 2. * PWM devices in a given group must be configured with the @@ -318,8 +314,7 @@ static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, * We're checking the period value of the second PWM device * in this group before applying the new config. */ - if ((atcbpwm && atcbpwm->duty > 0 && - atcbpwm->duty != atcbpwm->period) && + if ((atcbpwm->duty > 0 && atcbpwm->duty != atcbpwm->period) && (atcbpwm->div != i || atcbpwm->period != period)) { dev_err(pwmchip_parent(chip), "failed to configure period_ns: PWM group already configured with a different value\n"); -- cgit From c9a787b9456066d4bd34522f880bd16208d775dd Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Tue, 9 Jul 2024 11:22:21 +0200 Subject: pwm: atmel-tcb: Make private data variable naming consistent MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently the variables of type struct atmel_tcb_pwm_device are named "tcbpwm", and variables of type atmel_tcb_pwm_chip are either named "tcbpwm" (too!) or "tcbpwmc". Rename the chips with device name to "tcbpwmc" to get a consistent naming. Signed-off-by: Uwe Kleine-König Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20240709092221.47025-2-u.kleine-koenig@baylibre.com Signed-off-by: Uwe Kleine-König --- drivers/pwm/pwm-atmel-tcb.c | 90 ++++++++++++++++++++++----------------------- 1 file changed, 45 insertions(+), 45 deletions(-) (limited to 'drivers/pwm/pwm-atmel-tcb.c') diff --git a/drivers/pwm/pwm-atmel-tcb.c b/drivers/pwm/pwm-atmel-tcb.c index 2feee3744b50..f9a9c12cbcdd 100644 --- a/drivers/pwm/pwm-atmel-tcb.c +++ b/drivers/pwm/pwm-atmel-tcb.c @@ -382,17 +382,17 @@ static int atmel_tcb_pwm_probe(struct platform_device *pdev) { struct pwm_chip *chip; const struct of_device_id *match; - struct atmel_tcb_pwm_chip *tcbpwm; + struct atmel_tcb_pwm_chip *tcbpwmc; const struct atmel_tcb_config *config; struct device_node *np = pdev->dev.of_node; char clk_name[] = "t0_clk"; int err; int channel; - chip = devm_pwmchip_alloc(&pdev->dev, NPWM, sizeof(*tcbpwm)); + chip = devm_pwmchip_alloc(&pdev->dev, NPWM, sizeof(*tcbpwmc)); if (IS_ERR(chip)) return PTR_ERR(chip); - tcbpwm = to_tcb_chip(chip); + tcbpwmc = to_tcb_chip(chip); err = of_property_read_u32(np, "reg", &channel); if (err < 0) { @@ -402,20 +402,20 @@ static int atmel_tcb_pwm_probe(struct platform_device *pdev) return err; } - tcbpwm->regmap = syscon_node_to_regmap(np->parent); - if (IS_ERR(tcbpwm->regmap)) - return PTR_ERR(tcbpwm->regmap); + tcbpwmc->regmap = syscon_node_to_regmap(np->parent); + if (IS_ERR(tcbpwmc->regmap)) + return PTR_ERR(tcbpwmc->regmap); - tcbpwm->slow_clk = of_clk_get_by_name(np->parent, "slow_clk"); - if (IS_ERR(tcbpwm->slow_clk)) - return PTR_ERR(tcbpwm->slow_clk); + tcbpwmc->slow_clk = of_clk_get_by_name(np->parent, "slow_clk"); + if (IS_ERR(tcbpwmc->slow_clk)) + return PTR_ERR(tcbpwmc->slow_clk); clk_name[1] += channel; - tcbpwm->clk = of_clk_get_by_name(np->parent, clk_name); - if (IS_ERR(tcbpwm->clk)) - tcbpwm->clk = of_clk_get_by_name(np->parent, "t0_clk"); - if (IS_ERR(tcbpwm->clk)) { - err = PTR_ERR(tcbpwm->clk); + tcbpwmc->clk = of_clk_get_by_name(np->parent, clk_name); + if (IS_ERR(tcbpwmc->clk)) + tcbpwmc->clk = of_clk_get_by_name(np->parent, "t0_clk"); + if (IS_ERR(tcbpwmc->clk)) { + err = PTR_ERR(tcbpwmc->clk); goto err_slow_clk; } @@ -423,22 +423,22 @@ static int atmel_tcb_pwm_probe(struct platform_device *pdev) config = match->data; if (config->has_gclk) { - tcbpwm->gclk = of_clk_get_by_name(np->parent, "gclk"); - if (IS_ERR(tcbpwm->gclk)) { - err = PTR_ERR(tcbpwm->gclk); + tcbpwmc->gclk = of_clk_get_by_name(np->parent, "gclk"); + if (IS_ERR(tcbpwmc->gclk)) { + err = PTR_ERR(tcbpwmc->gclk); goto err_clk; } } chip->ops = &atmel_tcb_pwm_ops; - tcbpwm->channel = channel; - tcbpwm->width = config->counter_width; + tcbpwmc->channel = channel; + tcbpwmc->width = config->counter_width; - err = clk_prepare_enable(tcbpwm->slow_clk); + err = clk_prepare_enable(tcbpwmc->slow_clk); if (err) goto err_gclk; - spin_lock_init(&tcbpwm->lock); + spin_lock_init(&tcbpwmc->lock); err = pwmchip_add(chip); if (err < 0) @@ -449,16 +449,16 @@ static int atmel_tcb_pwm_probe(struct platform_device *pdev) return 0; err_disable_clk: - clk_disable_unprepare(tcbpwm->slow_clk); + clk_disable_unprepare(tcbpwmc->slow_clk); err_gclk: - clk_put(tcbpwm->gclk); + clk_put(tcbpwmc->gclk); err_clk: - clk_put(tcbpwm->clk); + clk_put(tcbpwmc->clk); err_slow_clk: - clk_put(tcbpwm->slow_clk); + clk_put(tcbpwmc->slow_clk); return err; } @@ -466,14 +466,14 @@ err_slow_clk: static void atmel_tcb_pwm_remove(struct platform_device *pdev) { struct pwm_chip *chip = platform_get_drvdata(pdev); - struct atmel_tcb_pwm_chip *tcbpwm = to_tcb_chip(chip); + struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); pwmchip_remove(chip); - clk_disable_unprepare(tcbpwm->slow_clk); - clk_put(tcbpwm->gclk); - clk_put(tcbpwm->clk); - clk_put(tcbpwm->slow_clk); + clk_disable_unprepare(tcbpwmc->slow_clk); + clk_put(tcbpwmc->gclk); + clk_put(tcbpwmc->clk); + clk_put(tcbpwmc->slow_clk); } static const struct of_device_id atmel_tcb_pwm_dt_ids[] = { @@ -485,14 +485,14 @@ MODULE_DEVICE_TABLE(of, atmel_tcb_pwm_dt_ids); static int atmel_tcb_pwm_suspend(struct device *dev) { struct pwm_chip *chip = dev_get_drvdata(dev); - struct atmel_tcb_pwm_chip *tcbpwm = to_tcb_chip(chip); - struct atmel_tcb_channel *chan = &tcbpwm->bkup; - unsigned int channel = tcbpwm->channel; + struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); + struct atmel_tcb_channel *chan = &tcbpwmc->bkup; + unsigned int channel = tcbpwmc->channel; - regmap_read(tcbpwm->regmap, ATMEL_TC_REG(channel, CMR), &chan->cmr); - regmap_read(tcbpwm->regmap, ATMEL_TC_REG(channel, RA), &chan->ra); - regmap_read(tcbpwm->regmap, ATMEL_TC_REG(channel, RB), &chan->rb); - regmap_read(tcbpwm->regmap, ATMEL_TC_REG(channel, RC), &chan->rc); + regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(channel, CMR), &chan->cmr); + regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(channel, RA), &chan->ra); + regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(channel, RB), &chan->rb); + regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(channel, RC), &chan->rc); return 0; } @@ -500,17 +500,17 @@ static int atmel_tcb_pwm_suspend(struct device *dev) static int atmel_tcb_pwm_resume(struct device *dev) { struct pwm_chip *chip = dev_get_drvdata(dev); - struct atmel_tcb_pwm_chip *tcbpwm = to_tcb_chip(chip); - struct atmel_tcb_channel *chan = &tcbpwm->bkup; - unsigned int channel = tcbpwm->channel; + struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); + struct atmel_tcb_channel *chan = &tcbpwmc->bkup; + unsigned int channel = tcbpwmc->channel; - regmap_write(tcbpwm->regmap, ATMEL_TC_REG(channel, CMR), chan->cmr); - regmap_write(tcbpwm->regmap, ATMEL_TC_REG(channel, RA), chan->ra); - regmap_write(tcbpwm->regmap, ATMEL_TC_REG(channel, RB), chan->rb); - regmap_write(tcbpwm->regmap, ATMEL_TC_REG(channel, RC), chan->rc); + regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(channel, CMR), chan->cmr); + regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(channel, RA), chan->ra); + regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(channel, RB), chan->rb); + regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(channel, RC), chan->rc); if (chan->enabled) - regmap_write(tcbpwm->regmap, + regmap_write(tcbpwmc->regmap, ATMEL_TC_CLKEN | ATMEL_TC_SWTRG, ATMEL_TC_REG(channel, CCR)); -- cgit