Re: [PATCH v3 5/6] spi: at91-usart: add driver for at91-usart as spi

[Radu Pirea]

On 05/17/2018 08:04 AM, Mark Brown wrote:
> On Fri, May 11, 2018 at 01:38:21PM +0300, Radu Pirea wrote:
>
> > +config SPI_AT91_USART
> > +        tristate "Atmel USART Controller as SPI"
> > +	depends on HAS_DMA
> > +	depends on (ARCH_AT91 || COMPILE_TEST)
> > +        select MFD_AT91_USART
> > +	help
> > +	  This selects a driver for the AT91 USART Controller as SPI Master,
> > +	  present on AT91 and SAMA5 SoC series.
> > +
>
> This looks like there's some tab/space mixing going on here.
>
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Driver for AT91 USART Controllers as SPI
> > + *
> > + * Copyright (C) 2018 Microchip Technology Inc.
>
> Make the entire block a C++ comment so it looks more intentional rather
> tha mixing C and C++.

Hi Mark,

I know it's ugly, but SPDX license identifier must be in a separate 
comment block.

> > +static inline void at91_usart_spi_tx(struct at91_usart_spi *aus)
> > +{
> > +	unsigned int len = aus->current_transfer->len;
> > +	unsigned int remaining = aus->current_tx_remaining_bytes;
> > +	const u8  *tx_buf = aus->current_transfer->tx_buf;
> > +
> > +	if (tx_buf && remaining) {
> > +		if (at91_usart_spi_tx_ready(aus))
> > +			spi_writel(aus, THR, tx_buf[len - remaining]);
> > +			aus->current_tx_remaining_bytes--;
>
> Missing braces here - we only write to the FIFO if there's space but we
> unconditionally decrement the counter.

Thanks. I will fix it.

> > +	} else {
> > +		if (at91_usart_spi_tx_ready(aus))
> > +			spi_writel(aus, THR, US_DUMMY_TX);
> > +	}
> > +}
>
> This looks like you're open coding SPI_CONTROLLER_MUST_TX
>
> > +	int len = aus->current_transfer->len;
> > +	int remaining = aus->current_rx_remaining_bytes;
> > +	u8  *rx_buf = aus->current_transfer->rx_buf;
> > +
> > +	if (aus->current_rx_remaining_bytes) {
> > +		rx_buf[len - remaining] = spi_readb(aus, RHR);
> > +		aus->current_rx_remaining_bytes--;
> > +	} else {
> > +		spi_readb(aus, RHR);
> > +	}
>
> Similarly for _MUST_RX.
>
> > +	controller->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX;
>
> You're actually setting both flags...  this means that the handling for
> cases with missing TX or RX buffers can't happen.

Sorry. My mistake. I will remove unnecessary code.