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From:   Bartosz Golaszewski <brgl@bgdev.pl>
To:     Dipen Patel <dipenp@nvidia.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Andy Shevchenko <andy@kernel.org>
Cc:     timestamp@lists.linux.dev, linux-kernel@vger.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@linaro.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: [PATCH v2] hte: tegra194: don't access struct gpio_chip
Date:   Fri, 13 Oct 2023 09:23:40 +0200
Message-Id: <20231013072340.16411-1-brgl@bgdev.pl>
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From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Using struct gpio_chip is not safe as it will disappear if the
underlying driver is unbound for any reason. Switch to using reference
counted struct gpio_device and its dedicated accessors.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Tested-by: Dipen Patel <dipenp@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
[andy: used gpio_device_find_by_fwnode()]
Reviewed-by: Dipen Patel <dipenp@nvidia.com>
Link: https://lore.kernel.org/r/20231010151709.4104747-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
Dipen,

Can you retest this patch now rebased on top of current GPIO for-next?

v1 -> v2:
- rebase on top of current gpio/for-next

 drivers/hte/hte-tegra194.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/hte/hte-tegra194.c b/drivers/hte/hte-tegra194.c
index 6fe6897047ac..341a134cb7d0 100644
--- a/drivers/hte/hte-tegra194.c
+++ b/drivers/hte/hte-tegra194.c
@@ -132,7 +132,7 @@ struct tegra_hte_soc {
 	const struct tegra_hte_data *prov_data;
 	struct tegra_hte_line_data *line_data;
 	struct hte_chip *chip;
-	struct gpio_chip *c;
+	struct gpio_device *gdev;
 	void __iomem *regs;
 };
 
@@ -418,7 +418,7 @@ static int tegra_hte_line_xlate(struct hte_chip *gc,
 	 * HTE/GTE namespace.
 	 */
 	if (gs->prov_data->type == HTE_TEGRA_TYPE_GPIO && !args) {
-		line_id = desc->attr.line_id - gs->c->base;
+		line_id = desc->attr.line_id - gpio_device_get_base(gs->gdev);
 		map = gs->prov_data->map;
 		map_sz = gs->prov_data->map_sz;
 	} else if (gs->prov_data->type == HTE_TEGRA_TYPE_GPIO && args) {
@@ -645,7 +645,7 @@ static bool tegra_hte_match_from_linedata(const struct hte_chip *chip,
 	if (!hte_dev || (hte_dev->prov_data->type != HTE_TEGRA_TYPE_GPIO))
 		return false;
 
-	return hte_dev->c == gpiod_to_chip(hdesc->attr.line_data);
+	return hte_dev->gdev == gpiod_to_gpio_device(hdesc->attr.line_data);
 }
 
 static const struct of_device_id tegra_hte_of_match[] = {
@@ -673,14 +673,11 @@ static void tegra_gte_disable(void *data)
 	tegra_hte_writel(gs, HTE_TECTRL, 0);
 }
 
-static int tegra_get_gpiochip_from_name(struct gpio_chip *chip, void *data)
+static void tegra_hte_put_gpio_device(void *data)
 {
-	return !strcmp(chip->label, data);
-}
+	struct gpio_device *gdev = data;
 
-static int tegra_gpiochip_match(struct gpio_chip *chip, void *data)
-{
-	return chip->fwnode == of_node_to_fwnode(data);
+	gpio_device_put(gdev);
 }
 
 static int tegra_hte_probe(struct platform_device *pdev)
@@ -760,8 +757,8 @@ static int tegra_hte_probe(struct platform_device *pdev)
 
 		if (of_device_is_compatible(dev->of_node,
 					    "nvidia,tegra194-gte-aon")) {
-			hte_dev->c = gpiochip_find("tegra194-gpio-aon",
-						tegra_get_gpiochip_from_name);
+			hte_dev->gdev =
+				gpio_device_find_by_label("tegra194-gpio-aon");
 		} else {
 			gpio_ctrl = of_parse_phandle(dev->of_node,
 						     "nvidia,gpio-controller",
@@ -772,14 +769,19 @@ static int tegra_hte_probe(struct platform_device *pdev)
 				return -ENODEV;
 			}
 
-			hte_dev->c = gpiochip_find(gpio_ctrl,
-						   tegra_gpiochip_match);
+			hte_dev->gdev =
+				gpio_device_find_by_fwnode(of_fwnode_handle(gpio_ctrl));
 			of_node_put(gpio_ctrl);
 		}
 
-		if (!hte_dev->c)
+		if (!hte_dev->gdev)
 			return dev_err_probe(dev, -EPROBE_DEFER,
 					     "wait for gpio controller\n");
+
+		ret = devm_add_action_or_reset(dev, tegra_hte_put_gpio_device,
+					       hte_dev->gdev);
+		if (ret)
+			return ret;
 	}
 
 	hte_dev->chip = gc;
-- 
2.39.2