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Message-ID: <90ba18b8-1a31-498d-a103-5c91b80cea5b@kernel.org>
Date: Tue, 21 Nov 2023 06:57:56 +0100
From: Jiri Slaby <jirislaby@...nel.org>
To: Hugo Villeneuve <hugo@...ovil.com>, gregkh@...uxfoundation.org
Cc: linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
lech.perczak@...lingroup.com,
Hugo Villeneuve <hvilleneuve@...onoff.com>
Subject: Re: [PATCH v2 1/1] serial: sc16is7xx: improve regmap debugfs by using
one regmap per port
On 20. 11. 23, 17:39, Hugo Villeneuve wrote:
> From: Hugo Villeneuve <hvilleneuve@...onoff.com>
>
> With this current driver regmap implementation, it is hard to make sense
> of the register addresses displayed using the regmap debugfs interface,
> because they do not correspond to the actual register addresses documented
> in the datasheet. For example, register 1 is displayed as registers 04 thru
> 07:
...
> --- a/drivers/tty/serial/sc16is7xx.c
> +++ b/drivers/tty/serial/sc16is7xx.c
...
> #ifdef CONFIG_SERIAL_SC16IS7XX_SPI
> static int sc16is7xx_spi_probe(struct spi_device *spi)
> {
> const struct sc16is7xx_devtype *devtype;
> - struct regmap *regmap;
> + struct regmap *regmaps[2];
IMO, in all places, it would make sense to declare a VLA with
devtype->nr_uart.
> + unsigned int i;
> int ret;
>
> /* Setup SPI bus */
> @@ -1732,11 +1736,20 @@ static int sc16is7xx_spi_probe(struct spi_device *spi)
> devtype = (struct sc16is7xx_devtype *)id_entry->driver_data;
> }
>
> - regcfg.max_register = (0xf << SC16IS7XX_REG_SHIFT) |
> - (devtype->nr_uart - 1);
> - regmap = devm_regmap_init_spi(spi, ®cfg);
> + for (i = 0; i < devtype->nr_uart; i++) {
> + regcfg.name = sc16is7xx_regmap_name(i);
> + /*
> + * If read_flag_mask is 0, the regmap code sets it to a default
> + * of 0x80. Since we specify our own mask, we must add the READ
> + * bit ourselves:
> + */
> + regcfg.read_flag_mask = sc16is7xx_regmap_port_mask(i) |
> + SC16IS7XX_SPI_READ_BIT;
> + regcfg.write_flag_mask = sc16is7xx_regmap_port_mask(i);
> + regmaps[i] = devm_regmap_init_spi(spi, ®cfg);
As you trip over the array until devtype->nr_uart which is of course up
to 2. For now.
Or at least add an asserion: devtype->nr_uart <= 2 somewhere.
thanks,
--
js
suse labs
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