[PATCH RFC 3/6] gpio: mvebu: add PWM support for Armada 8k

[Russell King <rmk+kernel@xxxxxxxxxxxxxxx>]

Add support for PWM devices on the Armada 8k, which are useful on the
Macchiatobin and Clearfog GT 8K platforms for controlling the fan
speed.

Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
---
 drivers/gpio/gpio-mvebu.c | 166 +++++++++++++++++++++++++-------------
 1 file changed, 111 insertions(+), 55 deletions(-)

diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c
index ee13b11c5298..4abe298e9c0f 100644
--- a/drivers/gpio/gpio-mvebu.c
+++ b/drivers/gpio/gpio-mvebu.c
@@ -91,8 +91,16 @@
 #define MVEBU_GPIO_SOC_VARIANT_ARMADAXP 0x3
 #define MVEBU_GPIO_SOC_VARIANT_A8K	0x4
 
+#define MVEBU_PWM_SOC_VARIANT_ARMADA370	1
+#define MVEBU_PWM_SOC_VARIANT_A8K	2
+
 #define MVEBU_MAX_GPIO_PER_BANK		32
 
+struct mvebu_gpio_soc_variant {
+	int gpio;
+	int pwm;
+};
+
 struct mvebu_pwm {
 	struct regmap		*regs;
 	u32			 offset;
@@ -679,21 +687,17 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip,
 	else
 		state->duty_cycle = 1;
 
-	regmap_read(mvpwm->regs, mvebu_pwmreg_blink_off_duration(mvpwm), &u);
 	val = (unsigned long long)u;
+	regmap_read(mvpwm->regs, mvebu_pwmreg_blink_off_duration(mvpwm), &u);
+	val += (unsigned long long)u;
 	val *= NSEC_PER_SEC;
 	do_div(val, mvpwm->clk_rate);
-	if (val < state->duty_cycle) {
+	if (val > UINT_MAX)
+		state->period = UINT_MAX;
+	else if (val)
+		state->period = val;
+	else
 		state->period = 1;
-	} else {
-		val -= state->duty_cycle;
-		if (val > UINT_MAX)
-			state->period = UINT_MAX;
-		else if (val)
-			state->period = val;
-		else
-			state->period = 1;
-	}
 
 	regmap_read(mvchip->regs, GPIO_BLINK_EN_OFF + mvchip->offset, &u);
 	if (u)
@@ -779,6 +783,7 @@ static void __maybe_unused mvebu_pwm_resume(struct mvebu_gpio_chip *mvchip)
 }
 
 static int mvebu_pwm_probe(struct platform_device *pdev,
+			   const struct mvebu_gpio_soc_variant *soc_variant,
 			   struct mvebu_gpio_chip *mvchip,
 			   int id)
 {
@@ -787,27 +792,9 @@ static int mvebu_pwm_probe(struct platform_device *pdev,
 	void __iomem *base;
 	u32 set;
 
-	if (!of_device_is_compatible(mvchip->chip.of_node,
-				     "marvell,armada-370-gpio"))
+	if (!soc_variant->pwm)
 		return 0;
 
-	if (IS_ERR(mvchip->clk))
-		return PTR_ERR(mvchip->clk);
-
-	/*
-	 * Use set A for lines of GPIO chip with id 0, B for GPIO chip
-	 * with id 1. Don't allow further GPIO chips to be used for PWM.
-	 */
-	if (id == 0)
-		set = 0;
-	else if (id == 1)
-		set = U32_MAX;
-	else
-		return -EINVAL;
-
-	regmap_write(mvchip->regs,
-		     GPIO_BLINK_CNT_SELECT_OFF + mvchip->offset, set);
-
 	mvpwm = devm_kzalloc(dev, sizeof(struct mvebu_pwm), GFP_KERNEL);
 	if (!mvpwm)
 		return -ENOMEM;
@@ -815,20 +802,67 @@ static int mvebu_pwm_probe(struct platform_device *pdev,
 	mvchip->mvpwm = mvpwm;
 	mvpwm->mvchip = mvchip;
 
-	/*
-	 * There are only two sets of PWM configuration registers for
-	 * all the GPIO lines on those SoCs which this driver reserves
-	 * for the first two GPIO chips. So if the resource is missing
-	 * we can't treat it as an error.
-	 */
-	base = devm_platform_ioremap_resource_byname(pdev, "pwm");
-	if (IS_ERR(base))
-		return PTR_ERR(base);
+	switch (soc_variant->pwm) {
+	case MVEBU_PWM_SOC_VARIANT_ARMADA370:
+		if (IS_ERR(mvchip->clk))
+			return PTR_ERR(mvchip->clk);
+
+		/*
+		 * There are only two sets of PWM configuration registers for
+		 * all the GPIO lines on those SoCs which this driver reserves
+		 * for the first two GPIO chips. So if the resource is missing
+		 * we can't treat it as an error.
+		 */
+		base = devm_platform_ioremap_resource_byname(pdev, "pwm");
+		if (IS_ERR(base))
+			return PTR_ERR(base);
 
-	mvpwm->regs = devm_regmap_init_mmio(&pdev->dev, base,
-					    &mvebu_gpio_regmap_config);
-	if (IS_ERR(mvpwm->regs))
-		return PTR_ERR(mvpwm->regs);
+		mvpwm->regs = devm_regmap_init_mmio(&pdev->dev, base,
+						    &mvebu_gpio_regmap_config);
+		if (IS_ERR(mvpwm->regs))
+			return PTR_ERR(mvpwm->regs);
+
+		/*
+		 * Use set A for lines of GPIO chip with id 0, B for GPIO chip
+		 * with id 1. Don't allow further GPIO chips to be used for PWM.
+		 */
+		if (id == 0)
+			set = 0;
+		else if (id == 1)
+			set = U32_MAX;
+		else
+			return -EINVAL;
+		break;
+
+	case MVEBU_PWM_SOC_VARIANT_A8K:
+		/*
+		 * If there is no clock, this is an older DT, so avoid
+		 * registering the PWM.
+		 */
+		if (IS_ERR(mvchip->clk))
+			return 0;
+
+		mvpwm->regs = mvchip->regs;
+		switch (id) {
+		case 1:
+			mvpwm->offset = 0x1f0;
+			set = 0;
+			break;
+		case 2:
+			mvpwm->offset = 0x1f8;
+			set = U32_MAX;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	regmap_write(mvchip->regs,
+		     GPIO_BLINK_CNT_SELECT_OFF + mvchip->offset, set);
 
 	mvpwm->clk_rate = clk_get_rate(mvchip->clk);
 	if (!mvpwm->clk_rate) {
@@ -909,26 +943,48 @@ static void mvebu_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 #define mvebu_gpio_dbg_show NULL
 #endif
 
+static const struct mvebu_gpio_soc_variant mvebu_gpio_orion_variant = {
+	.gpio = MVEBU_GPIO_SOC_VARIANT_ORION,
+};
+
+static const struct mvebu_gpio_soc_variant mvebu_gpio_mv78200_variant = {
+	.gpio = MVEBU_GPIO_SOC_VARIANT_MV78200,
+};
+
+static const struct mvebu_gpio_soc_variant mvebu_gpio_armadaxp_variant = {
+	.gpio = MVEBU_GPIO_SOC_VARIANT_ARMADAXP,
+};
+
+static const struct mvebu_gpio_soc_variant mvebu_gpio_armada370_variant = {
+	.gpio = MVEBU_GPIO_SOC_VARIANT_ORION,
+	.pwm = MVEBU_PWM_SOC_VARIANT_ARMADA370,
+};
+
+static const struct mvebu_gpio_soc_variant mvebu_gpio_a8k_variant = {
+	.gpio = MVEBU_GPIO_SOC_VARIANT_A8K,
+	.pwm = MVEBU_PWM_SOC_VARIANT_A8K,
+};
+
 static const struct of_device_id mvebu_gpio_of_match[] = {
 	{
 		.compatible = "marvell,orion-gpio",
-		.data	    = (void *) MVEBU_GPIO_SOC_VARIANT_ORION,
+		.data	    = &mvebu_gpio_orion_variant,
 	},
 	{
 		.compatible = "marvell,mv78200-gpio",
-		.data	    = (void *) MVEBU_GPIO_SOC_VARIANT_MV78200,
+		.data	    = &mvebu_gpio_mv78200_variant,
 	},
 	{
 		.compatible = "marvell,armadaxp-gpio",
-		.data	    = (void *) MVEBU_GPIO_SOC_VARIANT_ARMADAXP,
+		.data	    = &mvebu_gpio_armadaxp_variant,
 	},
 	{
 		.compatible = "marvell,armada-370-gpio",
-		.data	    = (void *) MVEBU_GPIO_SOC_VARIANT_ORION,
+		.data	    = &mvebu_gpio_armada370_variant,
 	},
 	{
 		.compatible = "marvell,armada-8k-gpio",
-		.data       = (void *) MVEBU_GPIO_SOC_VARIANT_A8K,
+		.data       = &mvebu_gpio_a8k_variant,
 	},
 	{
 		/* sentinel */
@@ -1093,6 +1149,7 @@ static int mvebu_gpio_probe_syscon(struct platform_device *pdev,
 
 static int mvebu_gpio_probe(struct platform_device *pdev)
 {
+	const struct mvebu_gpio_soc_variant *soc_variant;
 	struct mvebu_gpio_chip *mvchip;
 	const struct of_device_id *match;
 	struct device_node *np = pdev->dev.of_node;
@@ -1100,15 +1157,14 @@ static int mvebu_gpio_probe(struct platform_device *pdev)
 	struct irq_chip_type *ct;
 	unsigned int ngpios;
 	bool have_irqs;
-	int soc_variant;
 	int i, cpu, id;
 	int err;
 
 	match = of_match_device(mvebu_gpio_of_match, &pdev->dev);
 	if (match)
-		soc_variant = (unsigned long) match->data;
+		soc_variant = match->data;
 	else
-		soc_variant = MVEBU_GPIO_SOC_VARIANT_ORION;
+		soc_variant = &mvebu_gpio_orion_variant;
 
 	/* Some gpio controllers do not provide irq support */
 	have_irqs = of_irq_count(np) != 0;
@@ -1139,7 +1195,7 @@ static int mvebu_gpio_probe(struct platform_device *pdev)
 	if (!IS_ERR(mvchip->clk))
 		clk_prepare_enable(mvchip->clk);
 
-	mvchip->soc_variant = soc_variant;
+	mvchip->soc_variant = soc_variant->gpio;
 	mvchip->chip.label = dev_name(&pdev->dev);
 	mvchip->chip.parent = &pdev->dev;
 	mvchip->chip.request = gpiochip_generic_request;
@@ -1157,7 +1213,7 @@ static int mvebu_gpio_probe(struct platform_device *pdev)
 	mvchip->chip.of_node = np;
 	mvchip->chip.dbg_show = mvebu_gpio_dbg_show;
 
-	if (soc_variant == MVEBU_GPIO_SOC_VARIANT_A8K)
+	if (soc_variant->gpio == MVEBU_GPIO_SOC_VARIANT_A8K)
 		err = mvebu_gpio_probe_syscon(pdev, mvchip);
 	else
 		err = mvebu_gpio_probe_raw(pdev, mvchip);
@@ -1168,7 +1224,7 @@ static int mvebu_gpio_probe(struct platform_device *pdev)
 	/*
 	 * Mask and clear GPIO interrupts.
 	 */
-	switch (soc_variant) {
+	switch (soc_variant->gpio) {
 	case MVEBU_GPIO_SOC_VARIANT_ORION:
 	case MVEBU_GPIO_SOC_VARIANT_A8K:
 		regmap_write(mvchip->regs,
@@ -1265,7 +1321,7 @@ static int mvebu_gpio_probe(struct platform_device *pdev)
 
 	/* Some MVEBU SoCs have simple PWM support for GPIO lines */
 	if (IS_ENABLED(CONFIG_PWM))
-		return mvebu_pwm_probe(pdev, mvchip, id);
+		return mvebu_pwm_probe(pdev, soc_variant, mvchip, id);
 
 	return 0;
 
-- 
2.20.1