Skip to content

SPI DW: Fix multiple SPI clients with different max clock speeds #8

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 2 commits into from
Closed

SPI DW: Fix multiple SPI clients with different max clock speeds #8

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
2e22e0f
Added support for multiple slaves with different baud rates.
Aug 18, 2016
70f33b9
Remove needless if statements
Aug 18, 2016
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
45 changes: 18 additions & 27 deletions drivers/spi/spi-dw.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -289,8 +289,6 @@ static int dw_spi_transfer_one(struct spi_master *master,
struct chip_data *chip = spi_get_ctldata(spi);
u8 imask = 0;
u16 txlevel = 0;
u16 clk_div = 0;
u32 speed = 0;
u32 cr0 = 0;
int ret;

Expand All @@ -309,34 +307,27 @@ static int dw_spi_transfer_one(struct spi_master *master,
cr0 = chip->cr0;

/* Handle per transfer options for bpw and speed */
if (transfer->speed_hz) {
speed = chip->speed_hz;

if ((transfer->speed_hz != speed) || !chip->clk_div) {
speed = transfer->speed_hz;

/* clk_div doesn't support odd number */
clk_div = (dws->max_freq / speed + 1) & 0xfffe;

chip->speed_hz = speed;
chip->clk_div = clk_div;

spi_set_clk(dws, chip->clk_div);
if (transfer->speed_hz != dws->cur_freq) {
if (transfer->speed_hz != chip->speed_hz) {
/* clk_div doesn't support odd number, round up so we won't
* exceed requested speed_hz */
chip->clk_div = ((dws->max_freq + (transfer->speed_hz>>1)) / transfer->speed_hz + 1) & 0xfffe;
chip->speed_hz = transfer->speed_hz;
}
dws->cur_freq = transfer->speed_hz;
spi_set_clk(dws, chip->clk_div);
}
if (transfer->bits_per_word) {
if (transfer->bits_per_word == 8) {
dws->n_bytes = 1;
dws->dma_width = 1;
} else if (transfer->bits_per_word == 16) {
dws->n_bytes = 2;
dws->dma_width = 2;
}
cr0 = (transfer->bits_per_word - 1)
| (chip->type << SPI_FRF_OFFSET)
| (spi->mode << SPI_MODE_OFFSET)
| (chip->tmode << SPI_TMOD_OFFSET);
if (transfer->bits_per_word == 8) {
dws->n_bytes = 1;
dws->dma_width = 1;
} else if (transfer->bits_per_word == 16) {
dws->n_bytes = 2;
dws->dma_width = 2;
}
cr0 = (transfer->bits_per_word - 1)
| (chip->type << SPI_FRF_OFFSET)
| (spi->mode << SPI_MODE_OFFSET)
| (chip->tmode << SPI_TMOD_OFFSET);

/*
* Adjust transfer mode if necessary. Requires platform dependent
Expand Down
1 change: 1 addition & 0 deletions drivers/spi/spi-dw.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -108,6 +108,7 @@ struct dw_spi {
int irq;
u32 fifo_len; /* depth of the FIFO buffer */
u32 max_freq; /* max bus freq supported */
u32 cur_freq; /* current bus frequency */

u32 reg_io_width; /* DR I/O width in bytes */
u16 bus_num;
Expand Down