linux-kernel - Re: [PATCH v1 4/6] serial: 8250_exar: Replace custom EEPROM read with eeprom

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Message-ID: <ZuR_OERZZY3QoAtH@smile.fi.intel.com>
Date: Fri, 13 Sep 2024 21:06:48 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Parker Newman <parker@...est.io>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jirislaby@...nel.org>, Arnd Bergmann <arnd@...db.de>,
	linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
	Parker Newman <pnewman@...necttech.com>
Subject: Re: [PATCH v1 4/6] serial: 8250_exar: Replace custom EEPROM read
 with eeprom_93cx6

On Fri, Sep 13, 2024 at 10:55:41AM -0400, Parker Newman wrote:
> From: Parker Newman <pnewman@...necttech.com>
> 
> Replace the custom 93cx6 EEPROM read functions with the eeprom_93cx6
> driver. This removes duplicate code and improves code readability.
> 
> exar_ee_read() calls are replaced with eeprom_93cx6_read() or
> eeprom_93cx6_multiread().
> 
> Link to discussion with Andy Shevchenko:

(the above might need to be rephrased a bit, see below why)

> Link: https://lore.kernel.org/linux-serial/Ztr5u2wEt8VF1IdI@black.fi.intel.com/

Make it real tag by moving...

> Note: Old exar_ee_read() and associated functions are removed in next
> patch in this series.
> 

...somewhere here.

> Signed-off-by: Parker Newman <pnewman@...necttech.com>

...

>  #include <linux/property.h>
>  #include <linux/string.h>
>  #include <linux/types.h>
> +#include <linux/eeprom_93cx6.h>

Keep it sorted.

...

> +static void exar_eeprom_93cx6_reg_read(struct eeprom_93cx6 *eeprom)
> +{
> +	struct exar8250 *priv = (struct exar8250 *)eeprom->data;

Unneeded explicit cast.

> +	u8 regb = exar_read_reg(priv, UART_EXAR_REGB);
> +
> +	// EECK and EECS always read 0 from REGB so only set EEDO

Please, use C comment style as everywhere else in the file.

> +	eeprom->reg_data_out = regb & UART_EXAR_REGB_EEDO;
> +}

...

> +static void exar_eeprom_93cx6_reg_write(struct eeprom_93cx6 *eeprom)
> +{
> +	struct exar8250 *priv = (struct exar8250 *)eeprom->data;

Unneeded cast from void *.

> +	u8 regb = 0;
> +
> +	if (eeprom->reg_data_in)
> +		regb |= UART_EXAR_REGB_EEDI;
> +	if (eeprom->reg_data_clock)
> +		regb |= UART_EXAR_REGB_EECK;
> +	if (eeprom->reg_chip_select)
> +		regb |= UART_EXAR_REGB_EECS;
> +
> +	exar_write_reg(priv, UART_EXAR_REGB, regb);
> +}

...

> +       priv->eeprom.data = (void *)priv;

Unneeded cast.

...

> +	eeprom_93cx6_multiread(&priv->eeprom, eeprom_offset,
> +				(__le16 *)&osc_freq_le, 2);

Okay, this should be done better I believe:

	/* ...Find better names for variables... */
	__le16 f[2];
	u32 osc_freq;

	eeprom_93cx6_multiread(&priv->eeprom, eeprom_offset, &freq, ARRAY_SIZE(freq));

	osc_freq = le16_to_cpu(f[0]) | (le16_to_cpu(f[1]) << 16);
	if (osc_freq == GENMASK(31, 0))
		...

	return osc_freq;

(Also no need to break on 80 characters)

> +	if (osc_freq_le == 0xFFFFFFFF)
>  		return -EIO;
> 
> +	return le32_to_cpu(osc_freq_le);

-- 
With Best Regards,
Andy Shevchenko