diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c index 88c6efeebe06..0c7bd1aa7719 100644 --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c @@ -2,8 +2,8 @@ // // mcp251xfd - Microchip MCP251xFD Family CAN controller driver // -// Copyright (c) 2019, 2020 Pengutronix, -// Marc Kleine-Budde +// Copyright (c) 2019, 2020, 2021 Pengutronix, +// Marc Kleine-Budde // // Based on: // @@ -330,6 +330,7 @@ static void mcp251xfd_ring_init(struct mcp251xfd_priv *priv) struct mcp251xfd_tx_ring *tx_ring; struct mcp251xfd_rx_ring *rx_ring, *prev_rx_ring = NULL; struct mcp251xfd_tx_obj *tx_obj; + struct spi_transfer *xfer; u32 val; u16 addr; u8 len; @@ -347,8 +348,6 @@ static void mcp251xfd_ring_init(struct mcp251xfd_priv *priv) addr, val, val); for (j = 0; j < ARRAY_SIZE(tef_ring->uinc_xfer); j++) { - struct spi_transfer *xfer; - xfer = &tef_ring->uinc_xfer[j]; xfer->tx_buf = &tef_ring->uinc_buf; xfer->len = len; @@ -357,6 +356,15 @@ static void mcp251xfd_ring_init(struct mcp251xfd_priv *priv) xfer->cs_change_delay.unit = SPI_DELAY_UNIT_NSECS; } + /* "cs_change == 1" on the last transfer results in an active + * chip select after the complete SPI message. This causes the + * controller to interpret the next register access as + * data. Set "cs_change" of the last transfer to "0" to + * properly deactivate the chip select at the end of the + * message. + */ + xfer->cs_change = 0; + /* TX */ tx_ring = priv->tx; tx_ring->head = 0; @@ -397,8 +405,6 @@ static void mcp251xfd_ring_init(struct mcp251xfd_priv *priv) addr, val, val); for (j = 0; j < ARRAY_SIZE(rx_ring->uinc_xfer); j++) { - struct spi_transfer *xfer; - xfer = &rx_ring->uinc_xfer[j]; xfer->tx_buf = &rx_ring->uinc_buf; xfer->len = len; @@ -406,6 +412,15 @@ static void mcp251xfd_ring_init(struct mcp251xfd_priv *priv) xfer->cs_change_delay.value = 0; xfer->cs_change_delay.unit = SPI_DELAY_UNIT_NSECS; } + + /* "cs_change == 1" on the last transfer results in an + * active chip select after the complete SPI + * message. This causes the controller to interpret + * the next register access as data. Set "cs_change" + * of the last transfer to "0" to properly deactivate + * the chip select at the end of the message. + */ + xfer->cs_change = 0; } } @@ -1366,25 +1381,20 @@ static int mcp251xfd_handle_tefif(struct mcp251xfd_priv *priv) if (len) { struct mcp251xfd_tef_ring *ring = priv->tef; struct mcp251xfd_tx_ring *tx_ring = priv->tx; - struct spi_transfer *last_xfer; + int offset; /* Increment the TEF FIFO tail pointer 'len' times in * a single SPI message. * * Note: - * - * "cs_change == 1" on the last transfer results in an - * active chip select after the complete SPI - * message. This causes the controller to interpret - * the next register access as data. Temporary set - * "cs_change" of the last transfer to "0" to properly - * deactivate the chip select at the end of the - * message. + * Calculate offset, so that the SPI transfer ends on + * the last message of the uinc_xfer array, which has + * "cs_change == 0", to properly deactivate the chip + * select. */ - last_xfer = &ring->uinc_xfer[len - 1]; - last_xfer->cs_change = 0; - err = spi_sync_transfer(priv->spi, ring->uinc_xfer, len); - last_xfer->cs_change = 1; + offset = ARRAY_SIZE(ring->uinc_xfer) - len; + err = spi_sync_transfer(priv->spi, + ring->uinc_xfer + offset, len); if (err) return err; @@ -1536,7 +1546,7 @@ mcp251xfd_handle_rxif_ring(struct mcp251xfd_priv *priv, return err; while ((len = mcp251xfd_get_rx_linear_len(ring))) { - struct spi_transfer *last_xfer; + int offset; rx_tail = mcp251xfd_get_rx_tail(ring); @@ -1557,19 +1567,14 @@ mcp251xfd_handle_rxif_ring(struct mcp251xfd_priv *priv, * single SPI message. * * Note: - * - * "cs_change == 1" on the last transfer results in an - * active chip select after the complete SPI - * message. This causes the controller to interpret - * the next register access as data. Temporary set - * "cs_change" of the last transfer to "0" to properly - * deactivate the chip select at the end of the - * message. + * Calculate offset, so that the SPI transfer ends on + * the last message of the uinc_xfer array, which has + * "cs_change == 0", to properly deactivate the chip + * select. */ - last_xfer = &ring->uinc_xfer[len - 1]; - last_xfer->cs_change = 0; - err = spi_sync_transfer(priv->spi, ring->uinc_xfer, len); - last_xfer->cs_change = 1; + offset = ARRAY_SIZE(ring->uinc_xfer) - len; + err = spi_sync_transfer(priv->spi, + ring->uinc_xfer + offset, len); if (err) return err;