diff options
Diffstat (limited to 'drivers/spi/pxa2xx_spi.c')
| -rw-r--r-- | drivers/spi/pxa2xx_spi.c | 111 |
1 files changed, 90 insertions, 21 deletions
diff --git a/drivers/spi/pxa2xx_spi.c b/drivers/spi/pxa2xx_spi.c index 33fcef3150d4..885194a07418 100644 --- a/drivers/spi/pxa2xx_spi.c +++ b/drivers/spi/pxa2xx_spi.c @@ -28,6 +28,7 @@ #include <linux/workqueue.h> #include <linux/delay.h> #include <linux/clk.h> +#include <linux/gpio.h> #include <asm/io.h> #include <asm/irq.h> @@ -53,6 +54,7 @@ MODULE_ALIAS("platform:pxa2xx-spi"); #define RESET_DMA_CHANNEL (DCSR_NODESC | DMA_INT_MASK) #define IS_DMA_ALIGNED(x) ((((u32)(x)) & 0x07) == 0) #define MAX_DMA_LEN 8191 +#define DMA_ALIGNMENT 8 /* * for testing SSCR1 changes that require SSP restart, basically @@ -166,6 +168,8 @@ struct chip_data { u8 enable_dma; u8 bits_per_word; u32 speed_hz; + int gpio_cs; + int gpio_cs_inverted; int (*write)(struct driver_data *drv_data); int (*read)(struct driver_data *drv_data); void (*cs_control)(u32 command); @@ -173,6 +177,32 @@ struct chip_data { static void pump_messages(struct work_struct *work); +static void cs_assert(struct driver_data *drv_data) +{ + struct chip_data *chip = drv_data->cur_chip; + + if (chip->cs_control) { + chip->cs_control(PXA2XX_CS_ASSERT); + return; + } + + if (gpio_is_valid(chip->gpio_cs)) + gpio_set_value(chip->gpio_cs, chip->gpio_cs_inverted); +} + +static void cs_deassert(struct driver_data *drv_data) +{ + struct chip_data *chip = drv_data->cur_chip; + + if (chip->cs_control) { + chip->cs_control(PXA2XX_CS_DEASSERT); + return; + } + + if (gpio_is_valid(chip->gpio_cs)) + gpio_set_value(chip->gpio_cs, !chip->gpio_cs_inverted); +} + static int flush(struct driver_data *drv_data) { unsigned long limit = loops_per_jiffy << 1; @@ -183,16 +213,12 @@ static int flush(struct driver_data *drv_data) while (read_SSSR(reg) & SSSR_RNE) { read_SSDR(reg); } - } while ((read_SSSR(reg) & SSSR_BSY) && limit--); + } while ((read_SSSR(reg) & SSSR_BSY) && --limit); write_SSSR(SSSR_ROR, reg); return limit; } -static void null_cs_control(u32 command) -{ -} - static int null_writer(struct driver_data *drv_data) { void __iomem *reg = drv_data->ioaddr; @@ -400,7 +426,6 @@ static void giveback(struct driver_data *drv_data) msg = drv_data->cur_msg; drv_data->cur_msg = NULL; drv_data->cur_transfer = NULL; - drv_data->cur_chip = NULL; queue_work(drv_data->workqueue, &drv_data->pump_messages); spin_unlock_irqrestore(&drv_data->lock, flags); @@ -416,7 +441,7 @@ static void giveback(struct driver_data *drv_data) * a message with an error, or next message is for another chip */ if (!last_transfer->cs_change) - drv_data->cs_control(PXA2XX_CS_DEASSERT); + cs_deassert(drv_data); else { struct spi_message *next_msg; @@ -445,19 +470,21 @@ static void giveback(struct driver_data *drv_data) if (next_msg && next_msg->spi != msg->spi) next_msg = NULL; if (!next_msg || msg->state == ERROR_STATE) - drv_data->cs_control(PXA2XX_CS_DEASSERT); + cs_deassert(drv_data); } msg->state = NULL; if (msg->complete) msg->complete(msg->context); + + drv_data->cur_chip = NULL; } static int wait_ssp_rx_stall(void const __iomem *ioaddr) { unsigned long limit = loops_per_jiffy << 1; - while ((read_SSSR(ioaddr) & SSSR_BSY) && limit--) + while ((read_SSSR(ioaddr) & SSSR_BSY) && --limit) cpu_relax(); return limit; @@ -467,7 +494,7 @@ static int wait_dma_channel_stop(int channel) { unsigned long limit = loops_per_jiffy << 1; - while (!(DCSR(channel) & DCSR_STOPSTATE) && limit--) + while (!(DCSR(channel) & DCSR_STOPSTATE) && --limit) cpu_relax(); return limit; @@ -887,7 +914,7 @@ static void pump_transfers(unsigned long data) /* Drop chip select only if cs_change is requested */ if (previous->cs_change) - drv_data->cs_control(PXA2XX_CS_DEASSERT); + cs_deassert(drv_data); } /* Check for transfers that need multiple DMA segments */ @@ -922,7 +949,6 @@ static void pump_transfers(unsigned long data) } drv_data->n_bytes = chip->n_bytes; drv_data->dma_width = chip->dma_width; - drv_data->cs_control = chip->cs_control; drv_data->tx = (void *)transfer->tx_buf; drv_data->tx_end = drv_data->tx + transfer->len; drv_data->rx = transfer->rx_buf; @@ -1084,11 +1110,7 @@ static void pump_transfers(unsigned long data) write_SSTO(chip->timeout, reg); } - /* FIXME, need to handle cs polarity, - * this driver uses struct pxa2xx_spi_chip.cs_control to - * specify a CS handling function, and it ignores most - * struct spi_device.mode[s], including SPI_CS_HIGH */ - drv_data->cs_control(PXA2XX_CS_ASSERT); + cs_assert(drv_data); /* after chip select, release the data by enabling service * requests and interrupts, without changing any mode bits */ @@ -1166,6 +1188,44 @@ static int transfer(struct spi_device *spi, struct spi_message *msg) /* the spi->mode bits understood by this driver: */ #define MODEBITS (SPI_CPOL | SPI_CPHA) +static int setup_cs(struct spi_device *spi, struct chip_data *chip, + struct pxa2xx_spi_chip *chip_info) +{ + int err = 0; + + if (chip == NULL || chip_info == NULL) + return 0; + + /* NOTE: setup() can be called multiple times, possibly with + * different chip_info, release previously requested GPIO + */ + if (gpio_is_valid(chip->gpio_cs)) + gpio_free(chip->gpio_cs); + + /* If (*cs_control) is provided, ignore GPIO chip select */ + if (chip_info->cs_control) { + chip->cs_control = chip_info->cs_control; + return 0; + } + + if (gpio_is_valid(chip_info->gpio_cs)) { + err = gpio_request(chip_info->gpio_cs, "SPI_CS"); + if (err) { + dev_err(&spi->dev, "failed to request chip select " + "GPIO%d\n", chip_info->gpio_cs); + return err; + } + + chip->gpio_cs = chip_info->gpio_cs; + chip->gpio_cs_inverted = spi->mode & SPI_CS_HIGH; + + err = gpio_direction_output(chip->gpio_cs, + !chip->gpio_cs_inverted); + } + + return err; +} + static int setup(struct spi_device *spi) { struct pxa2xx_spi_chip *chip_info = NULL; @@ -1211,7 +1271,7 @@ static int setup(struct spi_device *spi) return -ENOMEM; } - chip->cs_control = null_cs_control; + chip->gpio_cs = -1; chip->enable_dma = 0; chip->timeout = TIMOUT_DFLT; chip->dma_burst_size = drv_data->master_info->enable_dma ? @@ -1225,8 +1285,6 @@ static int setup(struct spi_device *spi) /* chip_info isn't always needed */ chip->cr1 = 0; if (chip_info) { - if (chip_info->cs_control) - chip->cs_control = chip_info->cs_control; if (chip_info->timeout) chip->timeout = chip_info->timeout; if (chip_info->tx_threshold) @@ -1308,13 +1366,16 @@ static int setup(struct spi_device *spi) spi_set_ctldata(spi, chip); - return 0; + return setup_cs(spi, chip, chip_info); } static void cleanup(struct spi_device *spi) { struct chip_data *chip = spi_get_ctldata(spi); + if (gpio_is_valid(chip->gpio_cs)) + gpio_free(chip->gpio_cs); + kfree(chip); } @@ -1438,6 +1499,7 @@ static int __init pxa2xx_spi_probe(struct platform_device *pdev) master->bus_num = pdev->id; master->num_chipselect = platform_info->num_chipselect; + master->dma_alignment = DMA_ALIGNMENT; master->cleanup = cleanup; master->setup = setup; master->transfer = transfer; @@ -1638,6 +1700,13 @@ static int pxa2xx_spi_resume(struct platform_device *pdev) struct ssp_device *ssp = drv_data->ssp; int status = 0; + if (drv_data->rx_channel != -1) + DRCMR(drv_data->ssp->drcmr_rx) = + DRCMR_MAPVLD | drv_data->rx_channel; + if (drv_data->tx_channel != -1) + DRCMR(drv_data->ssp->drcmr_tx) = + DRCMR_MAPVLD | drv_data->tx_channel; + /* Enable the SSP clock */ clk_enable(ssp->clk); |