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Message-ID: <3c5e49d49a1cb5c2a54fe75ba315fe563e6575d9.camel@perches.com>
Subject: Re: [RFC Patch Resend 1/2] i2c debug counters as sysfs attributes
From:   Joe Perches <joe@perches.com>
To:     Sui Chen <suichen@google.com>, linux-kernel@vger.kernel.org
Date:   Tue, 09 Nov 2021 15:13:07 -0800
In-Reply-To: <20211109225321.618688-2-suichen@google.com>
References: <20211109225321.618688-1-suichen@google.com>
         <20211109225321.618688-2-suichen@google.com>
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On Tue, 2021-11-09 at 14:53 -0800, Sui Chen wrote:
> This change adds a few example I2C debug counters as sysfs attributes:
> - ber_cnt (bus error count)
> - nack_cnt (NACK count)
> - rec_fail_cnt, rec_succ_cnt (recovery failure/success count)
> - timeout_cnt (timeout count)
> - i2c_speed (bus frequency)
> 
> The function i2c_adapter_create_stats_folder creates a stats directory
> in the device's sysfs directory to hold the debug counters. The platform
> drivers will instantiate the counters in the stats directory if
> available.
[]
> diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
[]
> +static ssize_t ber_cnt_show(struct device* pdev,
> +	struct device_attribute* attr, char* buf) {
> +	u64* ber_cnt = kobj_to_adapter(pdev)->stats->ber_cnt;
> +	if (ber_cnt == NULL) return 0;
> +	ssize_t ret = sprintf(buf, "%llu\n", *ber_cnt);

Please do not declare after code.

And this should instead use:

	return sysfs_emit(buf, "%llu\n", *ber_cnt);

> +	return ret;
> +}
> +DEVICE_ATTR_RO(ber_cnt);
> +
> +ssize_t nack_cnt_show(struct device* pdev,
> +	struct device_attribute* attr, char* buf) {
> +	u64* nack_cnt = kobj_to_adapter(pdev)->stats->nack_cnt;
> +	if (nack_cnt == NULL) return 0;
> +	ssize_t ret = sprintf(buf, "%llu\n", *nack_cnt);

etc...