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spi: spi-pxa2xx: Add helpers for regiseters' accessing
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There are several registers for SPI, and the registers of 'SSCR0' and 'SSCR1'
are accessed frequently. This path is to introduce helper functions to
simplify the accessing of 'SSCR0' and 'SSCR1'.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Weike Chen <alvin.chen@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Weike Chen authored and Mark Brown committed Nov 24, 2014
1 parent 5d01410 commit 4fdb242
Showing 1 changed file with 84 additions and 23 deletions.
107 changes: 84 additions & 23 deletions drivers/spi/spi-pxa2xx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -80,6 +80,73 @@ static bool is_lpss_ssp(const struct driver_data *drv_data)
return drv_data->ssp_type == LPSS_SSP;
}

static u32 pxa2xx_spi_get_ssrc1_change_mask(const struct driver_data *drv_data)
{
switch (drv_data->ssp_type) {
default:
return SSCR1_CHANGE_MASK;
}
}

static u32
pxa2xx_spi_get_rx_default_thre(const struct driver_data *drv_data)
{
switch (drv_data->ssp_type) {
default:
return RX_THRESH_DFLT;
}
}

static bool pxa2xx_spi_txfifo_full(const struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
u32 mask;

switch (drv_data->ssp_type) {
default:
mask = SSSR_TFL_MASK;
break;
}

return (read_SSSR(reg) & mask) == mask;
}

static void pxa2xx_spi_clear_rx_thre(const struct driver_data *drv_data,
u32 *sccr1_reg)
{
u32 mask;

switch (drv_data->ssp_type) {
default:
mask = SSCR1_RFT;
break;
}
*sccr1_reg &= ~mask;
}

static void pxa2xx_spi_set_rx_thre(const struct driver_data *drv_data,
u32 *sccr1_reg, u32 threshold)
{
switch (drv_data->ssp_type) {
default:
*sccr1_reg |= SSCR1_RxTresh(threshold);
break;
}
}

static u32 pxa2xx_configure_sscr0(const struct driver_data *drv_data,
u32 clk_div, u8 bits)
{
switch (drv_data->ssp_type) {
default:
return clk_div
| SSCR0_Motorola
| SSCR0_DataSize(bits > 16 ? bits - 16 : bits)
| SSCR0_SSE
| (bits > 16 ? SSCR0_EDSS : 0);
}
}

/*
* Read and write LPSS SSP private registers. Caller must first check that
* is_lpss_ssp() returns true before these can be called.
Expand Down Expand Up @@ -234,7 +301,7 @@ static int null_writer(struct driver_data *drv_data)
void __iomem *reg = drv_data->ioaddr;
u8 n_bytes = drv_data->n_bytes;

if (((read_SSSR(reg) & SSSR_TFL_MASK) == SSSR_TFL_MASK)
if (pxa2xx_spi_txfifo_full(drv_data)
|| (drv_data->tx == drv_data->tx_end))
return 0;

Expand Down Expand Up @@ -262,7 +329,7 @@ static int u8_writer(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;

if (((read_SSSR(reg) & SSSR_TFL_MASK) == SSSR_TFL_MASK)
if (pxa2xx_spi_txfifo_full(drv_data)
|| (drv_data->tx == drv_data->tx_end))
return 0;

Expand All @@ -289,7 +356,7 @@ static int u16_writer(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;

if (((read_SSSR(reg) & SSSR_TFL_MASK) == SSSR_TFL_MASK)
if (pxa2xx_spi_txfifo_full(drv_data)
|| (drv_data->tx == drv_data->tx_end))
return 0;

Expand All @@ -316,7 +383,7 @@ static int u32_writer(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;

if (((read_SSSR(reg) & SSSR_TFL_MASK) == SSSR_TFL_MASK)
if (pxa2xx_spi_txfifo_full(drv_data)
|| (drv_data->tx == drv_data->tx_end))
return 0;

Expand Down Expand Up @@ -508,8 +575,9 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
* remaining RX bytes.
*/
if (pxa25x_ssp_comp(drv_data)) {
u32 rx_thre;

sccr1_reg &= ~SSCR1_RFT;
pxa2xx_spi_clear_rx_thre(drv_data, &sccr1_reg);

bytes_left = drv_data->rx_end - drv_data->rx;
switch (drv_data->n_bytes) {
Expand All @@ -519,10 +587,11 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
bytes_left >>= 1;
}

if (bytes_left > RX_THRESH_DFLT)
bytes_left = RX_THRESH_DFLT;
rx_thre = pxa2xx_spi_get_rx_default_thre(drv_data);
if (rx_thre > bytes_left)
rx_thre = bytes_left;

sccr1_reg |= SSCR1_RxTresh(bytes_left);
pxa2xx_spi_set_rx_thre(drv_data, &sccr1_reg, rx_thre);
}
write_SSCR1(sccr1_reg, reg);
}
Expand Down Expand Up @@ -613,6 +682,7 @@ static void pump_transfers(unsigned long data)
u32 cr1;
u32 dma_thresh = drv_data->cur_chip->dma_threshold;
u32 dma_burst = drv_data->cur_chip->dma_burst_size;
u32 change_mask = pxa2xx_spi_get_ssrc1_change_mask(drv_data);

/* Get current state information */
message = drv_data->cur_msg;
Expand Down Expand Up @@ -731,11 +801,7 @@ static void pump_transfers(unsigned long data)
"pump_transfers: DMA burst size reduced to match bits_per_word\n");
}

cr0 = clk_div
| SSCR0_Motorola
| SSCR0_DataSize(bits > 16 ? bits - 16 : bits)
| SSCR0_SSE
| (bits > 16 ? SSCR0_EDSS : 0);
cr0 = pxa2xx_configure_sscr0(drv_data, clk_div, bits);
}

message->state = RUNNING_STATE;
Expand Down Expand Up @@ -772,16 +838,15 @@ static void pump_transfers(unsigned long data)
}

/* see if we need to reload the config registers */
if ((read_SSCR0(reg) != cr0)
|| (read_SSCR1(reg) & SSCR1_CHANGE_MASK) !=
(cr1 & SSCR1_CHANGE_MASK)) {
if ((read_SSCR0(reg) != cr0) ||
(read_SSCR1(reg) & change_mask) != (cr1 & change_mask)) {

/* stop the SSP, and update the other bits */
write_SSCR0(cr0 & ~SSCR0_SSE, reg);
if (!pxa25x_ssp_comp(drv_data))
write_SSTO(chip->timeout, reg);
/* first set CR1 without interrupt and service enables */
write_SSCR1(cr1 & SSCR1_CHANGE_MASK, reg);
write_SSCR1(cr1 & change_mask, reg);
/* restart the SSP */
write_SSCR0(cr0, reg);

Expand Down Expand Up @@ -959,12 +1024,8 @@ static int setup(struct spi_device *spi)
clk_div = ssp_get_clk_div(drv_data, spi->max_speed_hz);
chip->speed_hz = spi->max_speed_hz;

chip->cr0 = clk_div
| SSCR0_Motorola
| SSCR0_DataSize(spi->bits_per_word > 16 ?
spi->bits_per_word - 16 : spi->bits_per_word)
| SSCR0_SSE
| (spi->bits_per_word > 16 ? SSCR0_EDSS : 0);
chip->cr0 = pxa2xx_configure_sscr0(drv_data, clk_div,
spi->bits_per_word);
chip->cr1 &= ~(SSCR1_SPO | SSCR1_SPH);
chip->cr1 |= (((spi->mode & SPI_CPHA) != 0) ? SSCR1_SPH : 0)
| (((spi->mode & SPI_CPOL) != 0) ? SSCR1_SPO : 0);
Expand Down

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