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Message-ID: <147fe15c-13d3-60dc-bd49-cd0cb40126e9@nvidia.com>
Date:   Tue, 10 Oct 2023 12:31:29 -0700
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Subject: Re: [PATCH v1 2/4] hte: tegra194: don't access struct gpio_chip
Content-Language: en-US
From:   Dipen Patel <dipenp@nvidia.com>
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Bartosz Golaszewski <bartosz.golaszewski@linaro.org>,
        linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
        timestamp@lists.linux.dev, linux-tegra@vger.kernel.org
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <brgl@bgdev.pl>,
        Andy Shevchenko <andy@kernel.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>
References: <20231010151709.4104747-1-andriy.shevchenko@linux.intel.com>
 <20231010151709.4104747-3-andriy.shevchenko@linux.intel.com>
 <3e1e6acf-5862-9f35-cbe6-72bb17cf3851@nvidia.com>
In-Reply-To: <3e1e6acf-5862-9f35-cbe6-72bb17cf3851@nvidia.com>
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On 10/10/23 9:19 AM, Dipen Patel wrote:
> On 10/10/23 8:17 AM, Andy Shevchenko wrote:
>> 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()]
>> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>> ---
>>  drivers/hte/hte-tegra194.c | 33 +++++++++++++++++++--------------
>>  1 file changed, 19 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/hte/hte-tegra194.c b/drivers/hte/hte-tegra194.c
>> index 9fd3c00ff695..339ff5921ec8 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;
>>  };
>>  
>> @@ -421,7 +421,7 @@ 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) {
>> @@ -643,12 +643,15 @@ static irqreturn_t tegra_hte_isr(int irq, void *dev_id)
>>  static bool tegra_hte_match_from_linedata(const struct hte_chip *chip,
>>  					  const struct hte_ts_desc *hdesc)
>>  {
>> +	struct gpio_device *gdev __free(gpio_device_put) = NULL;
>>  	struct tegra_hte_soc *hte_dev = chip->data;
>>  
>>  	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);
>> +	gdev = gpiod_to_device(hdesc->attr.line_data);
>> +
>> +	return hte_dev->gdev == gdev;
>>  }
>>  
>>  static const struct of_device_id tegra_hte_of_match[] = {
>> @@ -676,14 +679,11 @@ 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)
>> @@ -763,8 +763,8 @@ 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",
>> @@ -775,14 +775,19 @@ 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_fnode_handle(gpio_ctrl));

I think there is typo for of_fnode*. Should it be of_fwnode*?

>>  			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;
> 
> Looks good to me, I will wait for others to comment and will test out (2,3,4
> also) probably end of the day 11th Oct.
>