From 2a741cd6ec5899cec054ae27120f490ad57bc6bb Mon Sep 17 00:00:00 2001 From: Justin Swartz Date: Sat, 16 Mar 2024 03:03:01 +0200 Subject: spi: mt7621: allow GPIO chip select lines Extract a magic number, from mt7621_spi_probe(), used to declare the number of chip select lines (which co-incides with the native chip select count of 2) to a macro. Use the newly defined MT7621_NATIVE_CS_COUNT macro to instead populate both the spi_controller's max_native_cs and num_chipselect members. Declare that the spi_controller should use_gpio_descriptors if present in the device properties (such as those declared in the cs-gpio property of a "ralink,mt7621-spi" compatible device-tree node) so that the SPI core will recalculcate num_chipselect to account for the GPIO descriptors that it should have populated in the cs_gpiod array member. Remove the assignment of mt7621_spi_transfer_one_message() to the spi_controller's transfer_one_message hook. Refactor the mt7621_spi_transfer_one_message() logic into mt7621_spi_prepare_message() and mt7621_spi_transfer_one() and assign both to the spi_controller's prepare_message and transfer_one hooks respectively. Migrate the call mt7621_spi_transfer_one_message() made to mt7621_spi_flush() just before chip select deactivation, to the end of mt7621_spi_write_half_duplex() to ensure that any pending data is shifted out of MOSI before the SPI core deactivates the chip select line. As chip select activation is now taken care of by the SPI core, due to the use of the transfer_one hook instead of transfer_one_message, the calls to mt7621_spi_set_cs() from mt7621_spi_transfer_one_message() have fallen away. And although the SPI core will handle activation for GPIO chip select lines behind the scenes, it requires a callback to allow the driver to perform controller-specific operations to control its native chip select lines. Rename mt7621_spi_set_cs() to mt7621_spi_set_native_cs() and make sure that it takes into account the activation polarity of the chip select line it's acting upon, as the passed enable parameter represents the desired line level and not the desired activation state, and then assign mt7621_set_cs() to the spi_controller's set_cs hook. Signed-off-by: Justin Swartz Link: https://msgid.link/r/20240316010302.20776-1-justin.swartz@risingedge.co.za Reviewed-by: AngeloGioacchino Del Regno Signed-off-by: Mark Brown --- drivers/spi/spi-mt7621.c | 95 +++++++++++++++++++++++------------------------- 1 file changed, 45 insertions(+), 50 deletions(-) (limited to 'drivers/spi/spi-mt7621.c') diff --git a/drivers/spi/spi-mt7621.c b/drivers/spi/spi-mt7621.c index 4e9053d03d5a..3770b8e096a4 100644 --- a/drivers/spi/spi-mt7621.c +++ b/drivers/spi/spi-mt7621.c @@ -52,6 +52,8 @@ #define MT7621_CPOL BIT(4) #define MT7621_LSB_FIRST BIT(3) +#define MT7621_NATIVE_CS_COUNT 2 + struct mt7621_spi { struct spi_controller *host; void __iomem *base; @@ -75,10 +77,11 @@ static inline void mt7621_spi_write(struct mt7621_spi *rs, u32 reg, u32 val) iowrite32(val, rs->base + reg); } -static void mt7621_spi_set_cs(struct spi_device *spi, int enable) +static void mt7621_spi_set_native_cs(struct spi_device *spi, bool enable) { struct mt7621_spi *rs = spidev_to_mt7621_spi(spi); int cs = spi_get_chipselect(spi, 0); + bool active = spi->mode & SPI_CS_HIGH ? enable : !enable; u32 polar = 0; u32 host; @@ -94,7 +97,7 @@ static void mt7621_spi_set_cs(struct spi_device *spi, int enable) rs->pending_write = 0; - if (enable) + if (active) polar = BIT(cs); mt7621_spi_write(rs, MT7621_SPI_POLAR, polar); } @@ -154,6 +157,23 @@ static inline int mt7621_spi_wait_till_ready(struct mt7621_spi *rs) return -ETIMEDOUT; } +static int mt7621_spi_prepare_message(struct spi_controller *host, + struct spi_message *m) +{ + struct mt7621_spi *rs = spi_controller_get_devdata(host); + struct spi_device *spi = m->spi; + unsigned int speed = spi->max_speed_hz; + struct spi_transfer *t = NULL; + + mt7621_spi_wait_till_ready(rs); + + list_for_each_entry(t, &m->transfers, transfer_list) + if (t->speed_hz < speed) + speed = t->speed_hz; + + return mt7621_spi_prepare(spi, speed); +} + static void mt7621_spi_read_half_duplex(struct mt7621_spi *rs, int rx_len, u8 *buf) { @@ -243,59 +263,30 @@ static void mt7621_spi_write_half_duplex(struct mt7621_spi *rs, } rs->pending_write = len; + mt7621_spi_flush(rs); } -static int mt7621_spi_transfer_one_message(struct spi_controller *host, - struct spi_message *m) +static int mt7621_spi_transfer_one(struct spi_controller *host, + struct spi_device *spi, + struct spi_transfer *t) { struct mt7621_spi *rs = spi_controller_get_devdata(host); - struct spi_device *spi = m->spi; - unsigned int speed = spi->max_speed_hz; - struct spi_transfer *t = NULL; - int status = 0; - - mt7621_spi_wait_till_ready(rs); - list_for_each_entry(t, &m->transfers, transfer_list) - if (t->speed_hz < speed) - speed = t->speed_hz; - - if (mt7621_spi_prepare(spi, speed)) { - status = -EIO; - goto msg_done; - } - - /* Assert CS */ - mt7621_spi_set_cs(spi, 1); - - m->actual_length = 0; - list_for_each_entry(t, &m->transfers, transfer_list) { - if ((t->rx_buf) && (t->tx_buf)) { - /* - * This controller will shift some extra data out - * of spi_opcode if (mosi_bit_cnt > 0) && - * (cmd_bit_cnt == 0). So the claimed full-duplex - * support is broken since we have no way to read - * the MISO value during that bit. - */ - status = -EIO; - goto msg_done; - } else if (t->rx_buf) { - mt7621_spi_read_half_duplex(rs, t->len, t->rx_buf); - } else if (t->tx_buf) { - mt7621_spi_write_half_duplex(rs, t->len, t->tx_buf); - } - m->actual_length += t->len; + if ((t->rx_buf) && (t->tx_buf)) { + /* + * This controller will shift some extra data out + * of spi_opcode if (mosi_bit_cnt > 0) && + * (cmd_bit_cnt == 0). So the claimed full-duplex + * support is broken since we have no way to read + * the MISO value during that bit. + */ + return -EIO; + } else if (t->rx_buf) { + mt7621_spi_read_half_duplex(rs, t->len, t->rx_buf); + } else if (t->tx_buf) { + mt7621_spi_write_half_duplex(rs, t->len, t->tx_buf); } - /* Flush data and deassert CS */ - mt7621_spi_flush(rs); - mt7621_spi_set_cs(spi, 0); - -msg_done: - m->status = status; - spi_finalize_current_message(host); - return 0; } @@ -353,10 +344,14 @@ static int mt7621_spi_probe(struct platform_device *pdev) host->mode_bits = SPI_LSB_FIRST; host->flags = SPI_CONTROLLER_HALF_DUPLEX; host->setup = mt7621_spi_setup; - host->transfer_one_message = mt7621_spi_transfer_one_message; + host->prepare_message = mt7621_spi_prepare_message; + host->set_cs = mt7621_spi_set_native_cs; + host->transfer_one = mt7621_spi_transfer_one; host->bits_per_word_mask = SPI_BPW_MASK(8); host->dev.of_node = pdev->dev.of_node; - host->num_chipselect = 2; + host->max_native_cs = MT7621_NATIVE_CS_COUNT; + host->num_chipselect = MT7621_NATIVE_CS_COUNT; + host->use_gpio_descriptors = true; dev_set_drvdata(&pdev->dev, host); -- cgit v1.2.3