Merge tag 'pwm/for-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
 "Mostly cleanups and minor improvements with some new chip support for
  some drivers"

* tag 'pwm/for-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (37 commits)
  pwm: Remove set but not set variable 'pwm'
  pwm: sun4i: Initialize variables before use
  pwm: stm32: Remove automatic output enable
  pwm: sun4i: Narrow scope of local variable
  pwm: bcm2835: Allow building for ARCH_BRCMSTB
  pwm: imx27: Eliminate error message for defer probe
  pwm: sun4i: Fix inconsistent IS_ERR and PTR_ERR
  pwm: sun4i: Move pwm_calculate() out of spin_lock()
  pwm: omap-dmtimer: Allow compiling with COMPILE_TEST
  pwm: omap-dmtimer: put_device() after of_find_device_by_node()
  pwm: omap-dmtimer: Simplify error handling
  pwm: omap-dmtimer: Remove PWM chip in .remove before making it unfunctional
  pwm: Implement tracing for .get_state() and .apply_state()
  pwm: rcar: Document inability to set duty_cycle = 0
  pwm: rcar: Drop useless call to pwm_get_state()
  pwm: Fix minor Kconfig whitespace issues
  pwm: atmel: Implement .get_state()
  pwm: atmel: Use register accessors for channels
  pwm: atmel: Document known weaknesses of both hardware and software
  pwm: atmel: Replace loop in prescale calculation by ad-hoc calculation
  ...

Author: torvalds

Documentation/devicetree/bindings/pwm/mxs-pwm.txt

@@ -3,7 +3,7 @@ Freescale MXS PWM controller
 Required properties:
 - compatible: should be "fsl,imx23-pwm"
 - reg: physical base address and length of the controller's registers
-- #pwm-cells: should be 2. See pwm.yaml in this directory for a description of
+- #pwm-cells: should be 3. See pwm.yaml in this directory for a description of
   the cells format.
 - fsl,pwm-number: the number of PWM devices
 
@@ -12,6 +12,6 @@ Example:
 pwm: pwm@80064000 {
 	compatible = "fsl,imx28-pwm", "fsl,imx23-pwm";
 	reg = <0x80064000 0x2000>;
-	#pwm-cells = <2>;
+	#pwm-cells = <3>;
 	fsl,pwm-number = <8>;
 };

drivers/pwm/Kconfig

@@ -100,7 +100,7 @@ config PWM_BCM_KONA
 
 config PWM_BCM2835
 	tristate "BCM2835 PWM support"
-	depends on ARCH_BCM2835
+	depends on ARCH_BCM2835 || ARCH_BRCMSTB
 	help
 	  PWM framework driver for BCM2835 controller (Raspberry Pi)
 
@@ -328,7 +328,8 @@ config PWM_MXS
 
 config PWM_OMAP_DMTIMER
 	tristate "OMAP Dual-Mode Timer PWM support"
-	depends on OF && ARCH_OMAP && OMAP_DM_TIMER
+	depends on OF
+	depends on OMAP_DM_TIMER || COMPILE_TEST
 	help
 	  Generic PWM framework driver for OMAP Dual-Mode Timer PWM output
 
@@ -490,7 +491,7 @@ config PWM_TEGRA
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-tegra.
 
-config  PWM_TIECAP
+config PWM_TIECAP
 	tristate "ECAP PWM support"
 	depends on ARCH_OMAP2PLUS || ARCH_DAVINCI_DA8XX || ARCH_KEYSTONE || ARCH_K3
 	help
@@ -499,7 +500,7 @@ config  PWM_TIECAP
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-tiecap.
 
-config  PWM_TIEHRPWM
+config PWM_TIEHRPWM
 	tristate "EHRPWM PWM support"
 	depends on ARCH_OMAP2PLUS || ARCH_DAVINCI_DA8XX || ARCH_K3
 	help

drivers/pwm/core.c

@@ -20,6 +20,9 @@
 
 #include <dt-bindings/pwm/pwm.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/pwm.h>
+
 #define MAX_PWMS 1024
 
 static DEFINE_MUTEX(pwm_lookup_lock);
@@ -114,6 +117,11 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label)
 		}
 	}
 
+	if (pwm->chip->ops->get_state) {
+		pwm->chip->ops->get_state(pwm->chip, pwm, &pwm->state);
+		trace_pwm_get(pwm, &pwm->state);
+	}
+
 	set_bit(PWMF_REQUESTED, &pwm->flags);
 	pwm->label = label;
 
@@ -283,9 +291,6 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip,
 		pwm->hwpwm = i;
 		pwm->state.polarity = polarity;
 
-		if (chip->ops->get_state)
-			chip->ops->get_state(chip, pwm, &pwm->state);
-
 		radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
 	}
 
@@ -472,6 +477,8 @@ int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
 		if (err)
 			return err;
 
+		trace_pwm_apply(pwm, state);
+
 		pwm->state = *state;
 	} else {
 		/*

drivers/pwm/pwm-atmel.c

@@ -4,6 +4,19 @@
  *
  * Copyright (C) 2013 Atmel Corporation
  *		 Bo Shen <[email protected]>
+ *
+ * Links to reference manuals for the supported PWM chips can be found in
+ * Documentation/arm/microchip.rst.
+ *
+ * Limitations:
+ * - Periods start with the inactive level.
+ * - Hardware has to be stopped in general to update settings.
+ *
+ * Software bugs/possible improvements:
+ * - When atmel_pwm_apply() is called with state->enabled=false a change in
+ *   state->polarity isn't honored.
+ * - Instead of sleeping to wait for a completed period, the interrupt
+ *   functionality could be used.
  */
 
 #include <linux/clk.h>
@@ -47,6 +60,8 @@
 #define PWMV2_CPRD		0x0C
 #define PWMV2_CPRDUPD		0x10
 
+#define PWM_MAX_PRES		10
+
 struct atmel_pwm_registers {
 	u8 period;
 	u8 period_upd;
@@ -55,8 +70,7 @@ struct atmel_pwm_registers {
 };
 
 struct atmel_pwm_config {
-	u32 max_period;
-	u32 max_pres;
+	u32 period_bits;
 };
 
 struct atmel_pwm_data {
@@ -97,7 +111,7 @@ static inline u32 atmel_pwm_ch_readl(struct atmel_pwm_chip *chip,
 {
 	unsigned long base = PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE;
 
-	return readl_relaxed(chip->base + base + offset);
+	return atmel_pwm_readl(chip, base + offset);
 }
 
 static inline void atmel_pwm_ch_writel(struct atmel_pwm_chip *chip,
@@ -106,7 +120,7 @@ static inline void atmel_pwm_ch_writel(struct atmel_pwm_chip *chip,
 {
 	unsigned long base = PWM_CH_REG_OFFSET + ch * PWM_CH_REG_SIZE;
 
-	writel_relaxed(val, chip->base + base + offset);
+	atmel_pwm_writel(chip, base + offset, val);
 }
 
 static int atmel_pwm_calculate_cprd_and_pres(struct pwm_chip *chip,
@@ -115,17 +129,27 @@ static int atmel_pwm_calculate_cprd_and_pres(struct pwm_chip *chip,
 {
 	struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
 	unsigned long long cycles = state->period;
+	int shift;
 
 	/* Calculate the period cycles and prescale value */
 	cycles *= clk_get_rate(atmel_pwm->clk);
 	do_div(cycles, NSEC_PER_SEC);
 
-	for (*pres = 0; cycles > atmel_pwm->data->cfg.max_period; cycles >>= 1)
-		(*pres)++;
+	/*
+	 * The register for the period length is cfg.period_bits bits wide.
+	 * So for each bit the number of clock cycles is wider divide the input
+	 * clock frequency by two using pres and shift cprd accordingly.
+	 */
+	shift = fls(cycles) - atmel_pwm->data->cfg.period_bits;
 
-	if (*pres > atmel_pwm->data->cfg.max_pres) {
+	if (shift > PWM_MAX_PRES) {
 		dev_err(chip->dev, "pres exceeds the maximum value\n");
 		return -EINVAL;
+	} else if (shift > 0) {
+		*pres = shift;
+		cycles >>= *pres;
+	} else {
+		*pres = 0;
 	}
 
 	*cprd = cycles;
@@ -271,8 +295,48 @@ static int atmel_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	return 0;
 }
 
+static void atmel_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+				struct pwm_state *state)
+{
+	struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
+	u32 sr, cmr;
+
+	sr = atmel_pwm_readl(atmel_pwm, PWM_SR);
+	cmr = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR);
+
+	if (sr & (1 << pwm->hwpwm)) {
+		unsigned long rate = clk_get_rate(atmel_pwm->clk);
+		u32 cdty, cprd, pres;
+		u64 tmp;
+
+		pres = cmr & PWM_CMR_CPRE_MSK;
+
+		cprd = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm,
+					  atmel_pwm->data->regs.period);
+		tmp = (u64)cprd * NSEC_PER_SEC;
+		tmp <<= pres;
+		state->period = DIV64_U64_ROUND_UP(tmp, rate);
+
+		cdty = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm,
+					  atmel_pwm->data->regs.duty);
+		tmp = (u64)cdty * NSEC_PER_SEC;
+		tmp <<= pres;
+		state->duty_cycle = DIV64_U64_ROUND_UP(tmp, rate);
+
+		state->enabled = true;
+	} else {
+		state->enabled = false;
+	}
+
+	if (cmr & PWM_CMR_CPOL)
+		state->polarity = PWM_POLARITY_INVERSED;
+	else
+		state->polarity = PWM_POLARITY_NORMAL;
+}
+
 static const struct pwm_ops atmel_pwm_ops = {
 	.apply = atmel_pwm_apply,
+	.get_state = atmel_pwm_get_state,
 	.owner = THIS_MODULE,
 };
 
@@ -285,8 +349,7 @@ static const struct atmel_pwm_data atmel_sam9rl_pwm_data = {
 	},
 	.cfg = {
 		/* 16 bits to keep period and duty. */
-		.max_period	= 0xffff,
-		.max_pres	= 10,
+		.period_bits	= 16,
 	},
 };
 
@@ -299,8 +362,7 @@ static const struct atmel_pwm_data atmel_sama5_pwm_data = {
 	},
 	.cfg = {
 		/* 16 bits to keep period and duty. */
-		.max_period	= 0xffff,
-		.max_pres	= 10,
+		.period_bits	= 16,
 	},
 };
 
@@ -313,8 +375,7 @@ static const struct atmel_pwm_data mchp_sam9x60_pwm_data = {
 	},
 	.cfg = {
 		/* 32 bits to keep period and duty. */
-		.max_period	= 0xffffffff,
-		.max_pres	= 10,
+		.period_bits	= 32,
 	},
 };
 

drivers/pwm/pwm-cros-ec.c

@@ -25,11 +25,39 @@ struct cros_ec_pwm_device {
 	struct pwm_chip chip;
 };
 
+/**
+ * struct cros_ec_pwm - per-PWM driver data
+ * @duty_cycle: cached duty cycle
+ */
+struct cros_ec_pwm {
+	u16 duty_cycle;
+};
+
 static inline struct cros_ec_pwm_device *pwm_to_cros_ec_pwm(struct pwm_chip *c)
 {
 	return container_of(c, struct cros_ec_pwm_device, chip);
 }
 
+static int cros_ec_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct cros_ec_pwm *channel;
+
+	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
+	if (!channel)
+		return -ENOMEM;
+
+	pwm_set_chip_data(pwm, channel);
+
+	return 0;
+}
+
+static void cros_ec_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct cros_ec_pwm *channel = pwm_get_chip_data(pwm);
+
+	kfree(channel);
+}
+
 static int cros_ec_pwm_set_duty(struct cros_ec_device *ec, u8 index, u16 duty)
 {
 	struct {
@@ -96,7 +124,9 @@ static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			     const struct pwm_state *state)
 {
 	struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip);
-	int duty_cycle;
+	struct cros_ec_pwm *channel = pwm_get_chip_data(pwm);
+	u16 duty_cycle;
+	int ret;
 
 	/* The EC won't let us change the period */
 	if (state->period != EC_PWM_MAX_DUTY)
@@ -108,13 +138,20 @@ static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	 */
 	duty_cycle = state->enabled ? state->duty_cycle : 0;
 
-	return cros_ec_pwm_set_duty(ec_pwm->ec, pwm->hwpwm, duty_cycle);
+	ret = cros_ec_pwm_set_duty(ec_pwm->ec, pwm->hwpwm, duty_cycle);
+	if (ret < 0)
+		return ret;
+
+	channel->duty_cycle = state->duty_cycle;
+
+	return 0;
 }
 
 static void cros_ec_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 				  struct pwm_state *state)
 {
 	struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip);
+	struct cros_ec_pwm *channel = pwm_get_chip_data(pwm);
 	int ret;
 
 	ret = cros_ec_pwm_get_duty(ec_pwm->ec, pwm->hwpwm);
@@ -126,8 +163,19 @@ static void cros_ec_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 	state->enabled = (ret > 0);
 	state->period = EC_PWM_MAX_DUTY;
 
-	/* Note that "disabled" and "duty cycle == 0" are treated the same */
-	state->duty_cycle = ret;
+	/*
+	 * Note that "disabled" and "duty cycle == 0" are treated the same. If
+	 * the cached duty cycle is not zero, used the cached duty cycle. This
+	 * ensures that the configured duty cycle is kept across a disable and
+	 * enable operation and avoids potentially confusing consumers.
+	 *
+	 * For the case of the initial hardware readout, channel->duty_cycle
+	 * will be 0 and the actual duty cycle read from the EC is used.
+	 */
+	if (ret == 0 && channel->duty_cycle > 0)
+		state->duty_cycle = channel->duty_cycle;
+	else
+		state->duty_cycle = ret;
 }
 
 static struct pwm_device *
@@ -149,6 +197,8 @@ cros_ec_pwm_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
 }
 
 static const struct pwm_ops cros_ec_pwm_ops = {
+	.request = cros_ec_pwm_request,
+	.free = cros_ec_pwm_free,
 	.get_state	= cros_ec_pwm_get_state,
 	.apply		= cros_ec_pwm_apply,
 	.owner		= THIS_MODULE,