From f6f46de1063c8829713cd9d5b960dd8cb66cde8b Mon Sep 17 00:00:00 2001 From: Roland Stigge Date: Wed, 22 Aug 2012 15:49:17 +0200 Subject: spi/pl022: Add chip select handling via GPIO This patch adds the ability for the driver to control the chip select directly. This enables independence from cs_control callbacks. Configurable via platform_data, to be extended as DT in the following patch. Based on the initial patch by Alexandre Pereira da Silva Signed-off-by: Roland Stigge Acked-by: Alexandre Pereira da Silva Reviewed-by: Linus Walleij Signed-off-by: Mark Brown --- drivers/spi/spi-pl022.c | 48 ++++++++++++++++++++++++++++++++-------------- include/linux/amba/pl022.h | 2 ++ 2 files changed, 36 insertions(+), 14 deletions(-) diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c index 47c6753fb31..cf47802f00c 100644 --- a/drivers/spi/spi-pl022.c +++ b/drivers/spi/spi-pl022.c @@ -40,6 +40,7 @@ #include #include #include +#include /* * This macro is used to define some register default values. @@ -356,6 +357,8 @@ struct vendor_data { * @sgt_rx: scattertable for the RX transfer * @sgt_tx: scattertable for the TX transfer * @dummypage: a dummy page used for driving data on the bus with DMA + * @cur_cs: current chip select (gpio) + * @chipselects: list of chipselects (gpios) */ struct pl022 { struct amba_device *adev; @@ -389,6 +392,8 @@ struct pl022 { char *dummypage; bool dma_running; #endif + int cur_cs; + int *chipselects; }; /** @@ -433,6 +438,14 @@ static void null_cs_control(u32 command) pr_debug("pl022: dummy chip select control, CS=0x%x\n", command); } +static void pl022_cs_control(struct pl022 *pl022, u32 command) +{ + if (gpio_is_valid(pl022->cur_cs)) + gpio_set_value(pl022->cur_cs, command); + else + pl022->cur_chip->cs_control(command); +} + /** * giveback - current spi_message is over, schedule next message and call * callback of this message. Assumes that caller already @@ -479,7 +492,7 @@ static void giveback(struct pl022 *pl022) if (next_msg && next_msg->spi != pl022->cur_msg->spi) next_msg = NULL; if (!next_msg || pl022->cur_msg->state == STATE_ERROR) - pl022->cur_chip->cs_control(SSP_CHIP_DESELECT); + pl022_cs_control(pl022, SSP_CHIP_DESELECT); else pl022->next_msg_cs_active = true; @@ -818,8 +831,7 @@ static void dma_callback(void *data) /* Update total bytes transferred */ msg->actual_length += pl022->cur_transfer->len; if (pl022->cur_transfer->cs_change) - pl022->cur_chip-> - cs_control(SSP_CHIP_DESELECT); + pl022_cs_control(pl022, SSP_CHIP_DESELECT); /* Move to next transfer */ msg->state = next_transfer(pl022); @@ -1252,8 +1264,7 @@ static irqreturn_t pl022_interrupt_handler(int irq, void *dev_id) /* Update total bytes transferred */ msg->actual_length += pl022->cur_transfer->len; if (pl022->cur_transfer->cs_change) - pl022->cur_chip-> - cs_control(SSP_CHIP_DESELECT); + pl022_cs_control(pl022, SSP_CHIP_DESELECT); /* Move to next transfer */ msg->state = next_transfer(pl022); tasklet_schedule(&pl022->pump_transfers); @@ -1338,7 +1349,7 @@ static void pump_transfers(unsigned long data) /* Reselect chip select only if cs_change was requested */ if (previous->cs_change) - pl022->cur_chip->cs_control(SSP_CHIP_SELECT); + pl022_cs_control(pl022, SSP_CHIP_SELECT); } else { /* STATE_START */ message->state = STATE_RUNNING; @@ -1377,7 +1388,7 @@ static void do_interrupt_dma_transfer(struct pl022 *pl022) /* Enable target chip, if not already active */ if (!pl022->next_msg_cs_active) - pl022->cur_chip->cs_control(SSP_CHIP_SELECT); + pl022_cs_control(pl022, SSP_CHIP_SELECT); if (set_up_next_transfer(pl022, pl022->cur_transfer)) { /* Error path */ @@ -1429,12 +1440,12 @@ static void do_polling_transfer(struct pl022 *pl022) if (previous->delay_usecs) udelay(previous->delay_usecs); if (previous->cs_change) - pl022->cur_chip->cs_control(SSP_CHIP_SELECT); + pl022_cs_control(pl022, SSP_CHIP_SELECT); } else { /* STATE_START */ message->state = STATE_RUNNING; if (!pl022->next_msg_cs_active) - pl022->cur_chip->cs_control(SSP_CHIP_SELECT); + pl022_cs_control(pl022, SSP_CHIP_SELECT); } /* Configuration Changing Per Transfer */ @@ -1466,7 +1477,7 @@ static void do_polling_transfer(struct pl022 *pl022) /* Update total byte transferred */ message->actual_length += pl022->cur_transfer->len; if (pl022->cur_transfer->cs_change) - pl022->cur_chip->cs_control(SSP_CHIP_DESELECT); + pl022_cs_control(pl022, SSP_CHIP_DESELECT); /* Move to next transfer */ message->state = next_transfer(pl022); } @@ -1495,6 +1506,7 @@ static int pl022_transfer_one_message(struct spi_master *master, /* Setup the SPI using the per chip configuration */ pl022->cur_chip = spi_get_ctldata(msg->spi); + pl022->cur_cs = pl022->chipselects[msg->spi->chip_select]; restore_state(pl022); flush(pl022); @@ -1840,8 +1852,9 @@ static int pl022_setup(struct spi_device *spi) chip->xfer_type = chip_info->com_mode; if (!chip_info->cs_control) { chip->cs_control = null_cs_control; - dev_warn(&spi->dev, - "chip select function is NULL for this chip\n"); + if (!gpio_is_valid(pl022->chipselects[spi->chip_select])) + dev_warn(&spi->dev, + "invalid chip select\n"); } else chip->cs_control = chip_info->cs_control; @@ -1993,7 +2006,7 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id) struct pl022_ssp_controller *platform_info = adev->dev.platform_data; struct spi_master *master; struct pl022 *pl022 = NULL; /*Data for this driver */ - int status = 0; + int status = 0, i; dev_info(&adev->dev, "ARM PL022 driver, device ID: 0x%08x\n", adev->periphid); @@ -2004,7 +2017,8 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id) } /* Allocate master with space for data */ - master = spi_alloc_master(dev, sizeof(struct pl022)); + master = spi_alloc_master(dev, sizeof(struct pl022) + sizeof(int) * + platform_info->num_chipselect); if (master == NULL) { dev_err(&adev->dev, "probe - cannot alloc SPI master\n"); status = -ENOMEM; @@ -2016,6 +2030,8 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id) pl022->master_info = platform_info; pl022->adev = adev; pl022->vendor = id->data; + /* Point chipselects to allocated memory beyond the main struct */ + pl022->chipselects = (int *) pl022 + sizeof(struct pl022); /* * Bus Number Which has been Assigned to this SSP controller @@ -2030,6 +2046,10 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id) master->unprepare_transfer_hardware = pl022_unprepare_transfer_hardware; master->rt = platform_info->rt; + if (platform_info->num_chipselect && platform_info->chipselects) + for (i = 0; i < platform_info->num_chipselect; i++) + pl022->chipselects[i] = platform_info->chipselects[i]; + /* * Supports mode 0-3, loopback, and active low CS. Transfers are * always MS bit first on the original pl022. diff --git a/include/linux/amba/pl022.h b/include/linux/amba/pl022.h index fe1d7b283cb..854b7294f6c 100644 --- a/include/linux/amba/pl022.h +++ b/include/linux/amba/pl022.h @@ -244,6 +244,7 @@ struct dma_chan; * indicates no delay and the device will be suspended immediately. * @rt: indicates the controller should run the message pump with realtime * priority to minimise the transfer latency on the bus. + * @chipselects: list of chip select gpios */ struct pl022_ssp_controller { u16 bus_id; @@ -254,6 +255,7 @@ struct pl022_ssp_controller { void *dma_tx_param; int autosuspend_delay; bool rt; + int *chipselects; }; /** -- cgit v1.2.3-70-g09d2