From 45746e82cf89f432f9c986a52137d8a64b78aba9 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Mon, 2 Mar 2015 14:58:55 +0200 Subject: [PATCH] spi: dw: make sure SPI controller is enabled The error handling is partially broken since the controller is disabled on error and is not re-enabled until condition occurs, i.e. mode (poll, PIO/DMA), chip (cs_change), or speed (clk_div) is changed. In the result of these changes we will have a predictable state of the SPi controller independently on how successfull was a previous transfer. The patch disables interrupts and re-enables the SPI controller wherever it needs to be done. Thus most of the time the SPI controller is kept enabled. The runtime PM, when it will be implemented, must take care of the controller disabling and re-enabling. Signed-off-by: Andy Shevchenko Signed-off-by: Mark Brown --- drivers/spi/spi-dw.c | 7 ++----- drivers/spi/spi-dw.h | 12 ++++++++++++ 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c index 281121f00138..321965607fc0 100644 --- a/drivers/spi/spi-dw.c +++ b/drivers/spi/spi-dw.c @@ -272,8 +272,7 @@ static void giveback(struct dw_spi *dws) static void int_error_stop(struct dw_spi *dws, const char *msg) { - /* Stop the hw */ - spi_enable_chip(dws, 0); + spi_reset_chip(dws); dev_err(&dws->master->dev, "%s\n", msg); dws->cur_msg->state = ERROR_STATE; @@ -606,9 +605,7 @@ static void dw_spi_cleanup(struct spi_device *spi) /* Restart the controller, disable all interrupts, clean rx fifo */ static void spi_hw_init(struct device *dev, struct dw_spi *dws) { - spi_enable_chip(dws, 0); - spi_mask_intr(dws, 0xff); - spi_enable_chip(dws, 1); + spi_reset_chip(dws); /* * Try to detect the FIFO depth if not set by interface driver, diff --git a/drivers/spi/spi-dw.h b/drivers/spi/spi-dw.h index 3d32be68c142..1a7f083c2217 100644 --- a/drivers/spi/spi-dw.h +++ b/drivers/spi/spi-dw.h @@ -216,6 +216,18 @@ static inline void spi_umask_intr(struct dw_spi *dws, u32 mask) dw_writel(dws, DW_SPI_IMR, new_mask); } +/* + * This does disable the SPI controller, interrupts, and re-enable the + * controller back. Transmit and receive FIFO buffers are cleared when the + * device is disabled. + */ +static inline void spi_reset_chip(struct dw_spi *dws) +{ + spi_enable_chip(dws, 0); + spi_mask_intr(dws, 0xff); + spi_enable_chip(dws, 1); +} + /* * Each SPI slave device to work with dw_api controller should * has such a structure claiming its working mode (PIO/DMA etc), -- 2.20.1