[PATCH v2 1/10] pwm: mediatek: add a property "num-pwms"

[Sam Shih]

From: Ryder Lee <ryder.lee@xxxxxxxxxxxx>

This adds a property "num-pwms" to avoid having an endless
list of compatibles with no differences for the same driver.

Signed-off-by: Ryder Lee <ryder.lee@xxxxxxxxxxxx>
Signed-off-by: Sam Shih <sam.shih@xxxxxxxxxxxx>
---
Used: 
https://patchwork.kernel.org/project/linux-mediatek/list/?series=68207

Changes since v2:
- use num-pwms instead of mediatek,num-pwms.
- rename the member from num_pwms to fallback_num_pwms to make it more obvious
  that it doesn't represent the actually used value.
- add a dev_warn and a expressive comment to help other developers to not start
  adding num_pwms in the compatible_data.

Changes since v1:
- add some checks for backwards compatibility.
---
 drivers/pwm/pwm-mediatek.c | 35 ++++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
index eb6674c..f9d67fb 100644
--- a/drivers/pwm/pwm-mediatek.c
+++ b/drivers/pwm/pwm-mediatek.c
@@ -55,7 +55,7 @@ enum {
 };
 
 struct mtk_pwm_platform_data {
-	unsigned int num_pwms;
+	unsigned int fallback_npwms;
 	bool pwm45_fixup;
 	bool has_clks;
 };
@@ -226,27 +226,36 @@ static void mtk_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 
 static int mtk_pwm_probe(struct platform_device *pdev)
 {
-	const struct mtk_pwm_platform_data *data;
+	struct device_node *np = pdev->dev.of_node;
 	struct mtk_pwm_chip *pc;
 	struct resource *res;
-	unsigned int i;
+	unsigned int i, npwms;
 	int ret;
 
 	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
 	if (!pc)
 		return -ENOMEM;
 
-	data = of_device_get_match_data(&pdev->dev);
-	if (data == NULL)
-		return -EINVAL;
-	pc->soc = data;
+	pc->soc = of_device_get_match_data(&pdev->dev);
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	pc->regs = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(pc->regs))
 		return PTR_ERR(pc->regs);
 
-	for (i = 0; i < data->num_pwms + 2 && pc->soc->has_clks; i++) {
+	ret = of_property_read_u32(np, "num-pwms", &npwms);
+	if (ret < 0) {
+		/* It's deprecated, we should specify num_pwms via DT now. */
+		if (pc->soc->fallback_npwms) {
+			npwms = pc->soc->fallback_npwms;
+			dev_warn(&pdev->dev, "DT is outdated, please update it\n");
+		} else {
+			dev_err(&pdev->dev, "failed to get number of PWMs\n");
+			return ret;
+		}
+	}
+
+	for (i = 0; i < npwms + 2 && pc->soc->has_clks; i++) {
 		pc->clks[i] = devm_clk_get(&pdev->dev, mtk_pwm_clk_name[i]);
 		if (IS_ERR(pc->clks[i])) {
 			dev_err(&pdev->dev, "clock: %s fail: %ld\n",
@@ -260,7 +269,7 @@ static int mtk_pwm_probe(struct platform_device *pdev)
 	pc->chip.dev = &pdev->dev;
 	pc->chip.ops = &mtk_pwm_ops;
 	pc->chip.base = -1;
-	pc->chip.npwm = data->num_pwms;
+	pc->chip.npwm = npwms;
 
 	ret = pwmchip_add(&pc->chip);
 	if (ret < 0) {
@@ -279,25 +288,25 @@ static int mtk_pwm_remove(struct platform_device *pdev)
 }
 
 static const struct mtk_pwm_platform_data mt2712_pwm_data = {
-	.num_pwms = 8,
+	.fallback_npwms = 8,
 	.pwm45_fixup = false,
 	.has_clks = true,
 };
 
 static const struct mtk_pwm_platform_data mt7622_pwm_data = {
-	.num_pwms = 6,
+	.fallback_npwms = 6,
 	.pwm45_fixup = false,
 	.has_clks = true,
 };
 
 static const struct mtk_pwm_platform_data mt7623_pwm_data = {
-	.num_pwms = 5,
+	.fallback_npwms = 5,
 	.pwm45_fixup = true,
 	.has_clks = true,
 };
 
 static const struct mtk_pwm_platform_data mt7628_pwm_data = {
-	.num_pwms = 4,
+	.fallback_npwms = 4,
 	.pwm45_fixup = true,
 	.has_clks = false,
 };
-- 
1.9.1