[PATCH v1 1/5] pwm: mediatek: add a property "mediatek,num-pwms"

[Ryder Lee]

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

Thus, the driver should have backwards compatibility to older DTs.

Signed-off-by: Ryder Lee <ryder....@mediatek.com>
---
Changes since v1: add some checks for backwards compatibility.
---
 drivers/pwm/pwm-mediatek.c | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
index eb6674c..81b7e5e 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 num_pwms;  /* it should not be used in the future SoCs */
        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, num_pwms;
        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++) {
+       /* Check if we have set 'num-pwms' in DTs. */
+       ret = of_property_read_u32(np, "mediatek,num-pwms", &num_pwms);
+       if (ret < 0) {
+               /* If no, fallback to use SoC data for backwards compatibility. 
*/
+               if (pc->soc->num_pwms) {
+                       num_pwms = pc->soc->num_pwms;
+               } else {
+                       dev_err(&pdev->dev, "failed to get pwm number: %d\n", 
ret);
+                       return ret;
+               }
+       }
+
+       for (i = 0; i < num_pwms + 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 = num_pwms;
 
        ret = pwmchip_add(&pc->chip);
        if (ret < 0) {
-- 
1.9.1