summaryrefslogtreecommitdiffstats
path: root/drivers/spi/atmel_spi.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/spi/atmel_spi.c')
-rw-r--r--drivers/spi/atmel_spi.c134
1 files changed, 89 insertions, 45 deletions
diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index 8abae4ad0fa5..56ff3e6864ea 100644
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -30,13 +30,6 @@
* The core SPI transfer engine just talks to a register bank to set up
* DMA transfers; transfer queue progress is driven by IRQs. The clock
* framework provides the base clock, subdivided for each spi_device.
- *
- * Newer controllers, marked with "new_1" flag, have:
- * - CR.LASTXFER
- * - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
- * - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
- * - SPI_CSRx.CSAAT
- * - SPI_CSRx.SBCR allows faster clocking
*/
struct atmel_spi {
spinlock_t lock;
@@ -45,7 +38,6 @@ struct atmel_spi {
int irq;
struct clk *clk;
struct platform_device *pdev;
- unsigned new_1:1;
struct spi_device *stay;
u8 stopping;
@@ -59,10 +51,33 @@ struct atmel_spi {
dma_addr_t buffer_dma;
};
+/* Controller-specific per-slave state */
+struct atmel_spi_device {
+ unsigned int npcs_pin;
+ u32 csr;
+};
+
#define BUFFER_SIZE PAGE_SIZE
#define INVALID_DMA_ADDRESS 0xffffffff
/*
+ * Version 2 of the SPI controller has
+ * - CR.LASTXFER
+ * - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
+ * - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
+ * - SPI_CSRx.CSAAT
+ * - SPI_CSRx.SBCR allows faster clocking
+ *
+ * We can determine the controller version by reading the VERSION
+ * register, but I haven't checked that it exists on all chips, and
+ * this is cheaper anyway.
+ */
+static bool atmel_spi_is_v2(void)
+{
+ return !cpu_is_at91rm9200();
+}
+
+/*
* Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
* they assume that spi slave device state will not change on deselect, so
* that automagic deselection is OK. ("NPCSx rises if no data is to be
@@ -80,39 +95,58 @@ struct atmel_spi {
* Master on Chip Select 0.") No workaround exists for that ... so for
* nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
* and (c) will trigger that first erratum in some cases.
+ *
+ * TODO: Test if the atmel_spi_is_v2() branch below works on
+ * AT91RM9200 if we use some other register than CSR0. However, don't
+ * do this unconditionally since AP7000 has an errata where the BITS
+ * field in CSR0 overrides all other CSRs.
*/
static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
{
- unsigned gpio = (unsigned) spi->controller_data;
+ struct atmel_spi_device *asd = spi->controller_state;
unsigned active = spi->mode & SPI_CS_HIGH;
u32 mr;
- int i;
- u32 csr;
- u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
-
- /* Make sure clock polarity is correct */
- for (i = 0; i < spi->master->num_chipselect; i++) {
- csr = spi_readl(as, CSR0 + 4 * i);
- if ((csr ^ cpol) & SPI_BIT(CPOL))
- spi_writel(as, CSR0 + 4 * i, csr ^ SPI_BIT(CPOL));
- }
- mr = spi_readl(as, MR);
- mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
+ if (atmel_spi_is_v2()) {
+ /*
+ * Always use CSR0. This ensures that the clock
+ * switches to the correct idle polarity before we
+ * toggle the CS.
+ */
+ spi_writel(as, CSR0, asd->csr);
+ spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(MODFDIS)
+ | SPI_BIT(MSTR));
+ mr = spi_readl(as, MR);
+ gpio_set_value(asd->npcs_pin, active);
+ } else {
+ u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
+ int i;
+ u32 csr;
+
+ /* Make sure clock polarity is correct */
+ for (i = 0; i < spi->master->num_chipselect; i++) {
+ csr = spi_readl(as, CSR0 + 4 * i);
+ if ((csr ^ cpol) & SPI_BIT(CPOL))
+ spi_writel(as, CSR0 + 4 * i,
+ csr ^ SPI_BIT(CPOL));
+ }
+
+ mr = spi_readl(as, MR);
+ mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
+ if (spi->chip_select != 0)
+ gpio_set_value(asd->npcs_pin, active);
+ spi_writel(as, MR, mr);
+ }
dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
- gpio, active ? " (high)" : "",
+ asd->npcs_pin, active ? " (high)" : "",
mr);
-
- if (!(cpu_is_at91rm9200() && spi->chip_select == 0))
- gpio_set_value(gpio, active);
- spi_writel(as, MR, mr);
}
static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
{
- unsigned gpio = (unsigned) spi->controller_data;
+ struct atmel_spi_device *asd = spi->controller_state;
unsigned active = spi->mode & SPI_CS_HIGH;
u32 mr;
@@ -126,11 +160,11 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
}
dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
- gpio, active ? " (low)" : "",
+ asd->npcs_pin, active ? " (low)" : "",
mr);
- if (!(cpu_is_at91rm9200() && spi->chip_select == 0))
- gpio_set_value(gpio, !active);
+ if (atmel_spi_is_v2() || spi->chip_select != 0)
+ gpio_set_value(asd->npcs_pin, !active);
}
static inline int atmel_spi_xfer_is_last(struct spi_message *msg,
@@ -502,6 +536,7 @@ atmel_spi_interrupt(int irq, void *dev_id)
static int atmel_spi_setup(struct spi_device *spi)
{
struct atmel_spi *as;
+ struct atmel_spi_device *asd;
u32 scbr, csr;
unsigned int bits = spi->bits_per_word;
unsigned long bus_hz;
@@ -536,19 +571,16 @@ static int atmel_spi_setup(struct spi_device *spi)
}
/* see notes above re chipselect */
- if (cpu_is_at91rm9200()
+ if (!atmel_spi_is_v2()
&& spi->chip_select == 0
&& (spi->mode & SPI_CS_HIGH)) {
dev_dbg(&spi->dev, "setup: can't be active-high\n");
return -EINVAL;
}
- /*
- * Pre-new_1 chips start out at half the peripheral
- * bus speed.
- */
+ /* v1 chips start out at half the peripheral bus speed. */
bus_hz = clk_get_rate(as->clk);
- if (!as->new_1)
+ if (!atmel_spi_is_v2())
bus_hz /= 2;
if (spi->max_speed_hz) {
@@ -589,11 +621,20 @@ static int atmel_spi_setup(struct spi_device *spi)
/* chipselect must have been muxed as GPIO (e.g. in board setup) */
npcs_pin = (unsigned int)spi->controller_data;
- if (!spi->controller_state) {
+ asd = spi->controller_state;
+ if (!asd) {
+ asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
+ if (!asd)
+ return -ENOMEM;
+
ret = gpio_request(npcs_pin, spi->dev.bus_id);
- if (ret)
+ if (ret) {
+ kfree(asd);
return ret;
- spi->controller_state = (void *)npcs_pin;
+ }
+
+ asd->npcs_pin = npcs_pin;
+ spi->controller_state = asd;
gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH));
} else {
unsigned long flags;
@@ -605,11 +646,14 @@ static int atmel_spi_setup(struct spi_device *spi)
spin_unlock_irqrestore(&as->lock, flags);
}
+ asd->csr = csr;
+
dev_dbg(&spi->dev,
"setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
bus_hz / scbr, bits, spi->mode, spi->chip_select, csr);
- spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
+ if (!atmel_spi_is_v2())
+ spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
return 0;
}
@@ -626,8 +670,7 @@ static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
dev_dbg(controller, "new message %p submitted for %s\n",
msg, spi->dev.bus_id);
- if (unlikely(list_empty(&msg->transfers)
- || !spi->max_speed_hz))
+ if (unlikely(list_empty(&msg->transfers)))
return -EINVAL;
if (as->stopping)
@@ -684,10 +727,11 @@ static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
static void atmel_spi_cleanup(struct spi_device *spi)
{
struct atmel_spi *as = spi_master_get_devdata(spi->master);
+ struct atmel_spi_device *asd = spi->controller_state;
unsigned gpio = (unsigned) spi->controller_data;
unsigned long flags;
- if (!spi->controller_state)
+ if (!asd)
return;
spin_lock_irqsave(&as->lock, flags);
@@ -697,7 +741,9 @@ static void atmel_spi_cleanup(struct spi_device *spi)
}
spin_unlock_irqrestore(&as->lock, flags);
+ spi->controller_state = NULL;
gpio_free(gpio);
+ kfree(asd);
}
/*-------------------------------------------------------------------------*/
@@ -755,8 +801,6 @@ static int __init atmel_spi_probe(struct platform_device *pdev)
goto out_free_buffer;
as->irq = irq;
as->clk = clk;
- if (!cpu_is_at91rm9200())
- as->new_1 = 1;
ret = request_irq(irq, atmel_spi_interrupt, 0,
pdev->dev.bus_id, master);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-29 06:37:42 +0100