pwm: mtk-disp: Simplify using devm_pwmchip_add()

With devm_pwmchip_add() pwmchip_remove() can be dropped from the remove
callback. Then the remove callback is empty and can go away, too. With
mtk_disp_pwm_remove() the last user of platform_get_drvdata() is gone and
so platform_set_drvdata() can be dropped, too.

Also use dev_err_probe() for simplified (and improved) error reporting.

Link: https://lore.kernel.org/r/20230929161918.2410424-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

Author: Uwe Kleine-König

drivers/pwm/pwm-mtk-disp.c

@@ -246,34 +246,25 @@ static int mtk_disp_pwm_probe(struct platform_device *pdev)
 
 	mdp->clk_main = devm_clk_get(&pdev->dev, "main");
 	if (IS_ERR(mdp->clk_main))
-		return PTR_ERR(mdp->clk_main);
+		return dev_err_probe(&pdev->dev, PTR_ERR(mdp->clk_main),
+				     "Failed to get main clock\n");
 
 	mdp->clk_mm = devm_clk_get(&pdev->dev, "mm");
 	if (IS_ERR(mdp->clk_mm))
-		return PTR_ERR(mdp->clk_mm);
+		return dev_err_probe(&pdev->dev, PTR_ERR(mdp->clk_mm),
+				     "Failed to get mm clock\n");
 
 	mdp->chip.dev = &pdev->dev;
 	mdp->chip.ops = &mtk_disp_pwm_ops;
 	mdp->chip.npwm = 1;
 
-	ret = pwmchip_add(&mdp->chip);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "pwmchip_add() failed: %pe\n", ERR_PTR(ret));
-		return ret;
-	}
-
-	platform_set_drvdata(pdev, mdp);
+	ret = devm_pwmchip_add(&pdev->dev, &mdp->chip);
+	if (ret < 0)
+		return dev_err_probe(&pdev->dev, ret, "pwmchip_add() failed\n");
 
 	return 0;
 }
 
-static void mtk_disp_pwm_remove(struct platform_device *pdev)
-{
-	struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev);
-
-	pwmchip_remove(&mdp->chip);
-}
-
 static const struct mtk_pwm_data mt2701_pwm_data = {
 	.enable_mask = BIT(16),
 	.con0 = 0xa8,
@@ -319,7 +310,6 @@ static struct platform_driver mtk_disp_pwm_driver = {
 		.of_match_table = mtk_disp_pwm_of_match,
 	},
 	.probe = mtk_disp_pwm_probe,
-	.remove_new = mtk_disp_pwm_remove,
 };
 module_platform_driver(mtk_disp_pwm_driver);