[PATCH v3] spi/pl022: add devicetree support

From: Alexandre Pereira da Silva
Date: Tue Jun 26 2012 - 10:06:23 EST

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Add the chipselect array and cur_cs properties to pl022 main structure

Add a wrapper function to decide if the cs should be controlled by the
cs_control callback or the chipselect gpio

Populate chipselect property from cs-gpios

Populate master->dev.of_node, so the spi bus can find child spi
devices and register them

At pl022 setup, fill chip_data structure from dt nodes, if not provided
by platform.

Signed-off-by: Alexandre Pereira da Silva <aletes.xgr@xxxxxxxxx>
Tested-by: Roland Stigge <stigge@xxxxxxxxx>
---
Applies to v3.5-rc4

Changes since v2:
* Use IS_ENABLED instead of #ifdef
* Remove bogus const change

Changes since v1:
* return EPROBE_DEFFER if gpios are not initialized yet

Thanks Thierry Reding for reviewing and improvements suggestions

.../devicetree/bindings/spi/spi_pl022.txt | 15 +++
drivers/spi/spi-pl022.c | 115 ++++++++++++++++----
2 files changed, 111 insertions(+), 19 deletions(-)

diff --git a/Documentation/devicetree/bindings/spi/spi_pl022.txt b/Documentation/devicetree/bindings/spi/spi_pl022.txt
index 306ec3f..b089ec7 100644
--- a/Documentation/devicetree/bindings/spi/spi_pl022.txt
+++ b/Documentation/devicetree/bindings/spi/spi_pl022.txt
@@ -6,7 +6,22 @@ Required properties:
- interrupts : Should contain SPI controller interrupt

Optional properties:
+- pl022,num-chipselects : total number of chipselects
- cs-gpios : should specify GPIOs used for chipselects.
The gpios will be referred to as reg = <index> in the SPI child nodes.
If unspecified, a single SPI device without a chip select can be used.

+SPI slave nodes must be children of the SPI master node and can
+contain the following properties.
+See include/linux/amba/pl022.h for more details
+
+- pl022,hierarchy : master or slave interface
+- pl022,interface : interface type
+- pl022,slave-tx-disable : disconnect tx line in slave mode
+- pl022,com-mode : polling, interrupt or dma
+- pl022,rx-level-trig : Rx FIFO watermark level
+- pl022,tx-level-trig : Tx FIFO watermark level
+- pl022,ctrl-len : Microwire interface: Control length
+- pl022,wait-state : Microwire interface: Wait state
+- pl022,duplex : Microwire interface: Full/Half duplex
+
diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c
index 400ae21..fa11d0f 100644
--- a/drivers/spi/spi-pl022.c
+++ b/drivers/spi/spi-pl022.c
@@ -40,6 +40,8 @@
#include <linux/dma-mapping.h>
#include <linux/scatterlist.h>
#include <linux/pm_runtime.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>

/*
* This macro is used to define some register default values.
@@ -389,6 +391,8 @@ struct pl022 {
char *dummypage;
bool dma_running;
#endif
+ int cur_cs;
+ int chipselect[0];
};

/**
@@ -433,6 +437,14 @@ 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 +491,7 @@ 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;

@@ -813,8 +825,7 @@ 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);
@@ -1247,8 +1258,7 @@ 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);
@@ -1333,7 +1343,7 @@ 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;
@@ -1372,7 +1382,7 @@ 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 */
@@ -1424,12 +1434,12 @@ 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 */
@@ -1461,7 +1471,7 @@ 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);
}
@@ -1490,6 +1500,7 @@ 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->chipselect[msg->spi->chip_select];

restore_state(pl022);
flush(pl022);
@@ -1761,12 +1772,14 @@ static const struct pl022_config_chip pl022_default_chip_info = {
static int pl022_setup(struct spi_device *spi)
{
struct pl022_config_chip const *chip_info;
+ struct pl022_config_chip chip_info_dt;
struct chip_data *chip;
struct ssp_clock_params clk_freq = { .cpsdvsr = 0, .scr = 0};
int status = 0;
struct pl022 *pl022 = spi_master_get_devdata(spi->master);
unsigned int bits = spi->bits_per_word;
u32 tmp;
+ struct device_node *np = spi->dev.of_node;

if (!spi->max_speed_hz)
return -EINVAL;
@@ -1789,10 +1802,36 @@ static int pl022_setup(struct spi_device *spi)
chip_info = spi->controller_data;

if (chip_info == NULL) {
- chip_info = &pl022_default_chip_info;
- /* spi_board_info.controller_data not is supplied */
- dev_dbg(&spi->dev,
- "using default controller_data settings\n");
+ if (np) {
+ chip_info_dt = pl022_default_chip_info;
+
+ of_property_read_u32(np, "pl022,hierarchy",
+ &chip_info_dt.hierarchy);
+ of_property_read_u32(np, "pl022,interface",
+ &chip_info_dt.iface);
+ chip_info_dt.slave_tx_disable =
+ of_property_read_bool(np,
+ "pl022,slave-tx-disable");
+ of_property_read_u32(np, "pl022,com-mode",
+ &chip_info_dt.com_mode);
+ of_property_read_u32(np, "pl022,rx-level-trig",
+ &chip_info_dt.rx_lev_trig);
+ of_property_read_u32(np, "pl022,tx-level-trig",
+ &chip_info_dt.tx_lev_trig);
+ of_property_read_u32(np, "pl022,ctrl-len",
+ &chip_info_dt.ctrl_len);
+ of_property_read_u32(np, "pl022,wait-state",
+ &chip_info_dt.wait_state);
+ of_property_read_u32(np, "pl022,duplex",
+ &chip_info_dt.duplex);
+
+ chip_info = &chip_info_dt;
+ } else {
+ chip_info = &pl022_default_chip_info;
+ /* spi_board_info.controller_data not is supplied */
+ dev_dbg(&spi->dev,
+ "using default controller_data settings\n");
+ }
} else
dev_dbg(&spi->dev,
"using user supplied controller_data settings\n");
@@ -1835,8 +1874,9 @@ 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->chipselect[spi->chip_select]))
+ dev_warn(&spi->dev,
+ "chip select function is NULL for this chip\n");
} else
chip->cs_control = chip_info->cs_control;

@@ -1988,7 +2028,8 @@ 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;
+ struct device_node *np = adev->dev.of_node;
+ int status = 0, i, num_cs;

dev_info(&adev->dev,
"ARM PL022 driver, device ID: 0x%08x\n", adev->periphid);
@@ -1998,8 +2039,14 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id)
goto err_no_pdata;
}

+ num_cs = platform_info->num_chipselect;
+#if IS_ENABLED(CONFIG_OF)
+ of_property_read_u32(np, "pl022,num-chipselects", &num_cs);
+#endif
+
/* Allocate master with space for data */
- master = spi_alloc_master(dev, sizeof(struct pl022));
+ master = spi_alloc_master(dev,
+ sizeof(struct pl022) + sizeof(int) * num_cs);
if (master == NULL) {
dev_err(&adev->dev, "probe - cannot alloc SPI master\n");
status = -ENOMEM;
@@ -2017,13 +2064,40 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id)
* on this board
*/
master->bus_num = platform_info->bus_id;
- master->num_chipselect = platform_info->num_chipselect;
+ master->num_chipselect = num_cs;
master->cleanup = pl022_cleanup;
master->setup = pl022_setup;
master->prepare_transfer_hardware = pl022_prepare_transfer_hardware;
master->transfer_one_message = pl022_transfer_one_message;
master->unprepare_transfer_hardware = pl022_unprepare_transfer_hardware;
master->rt = platform_info->rt;
+ master->dev.of_node = dev->of_node;
+
+#if IS_ENABLED(CONFIG_OF)
+ for (i = 0; i < num_cs; i++) {
+ int cs_gpio = of_get_named_gpio(np, "cs-gpios", i);
+
+ if (cs_gpio == -EPROBE_DEFER) {
+ status = -EPROBE_DEFER;
+ goto err_no_gpio;
+ }
+
+ pl022->chipselect[i] = cs_gpio;
+
+ if (gpio_is_valid(cs_gpio)) {
+ if (gpio_request(cs_gpio, "ssp-pl022"))
+ dev_err(&adev->dev,
+ "could not request %d gpio\n", cs_gpio);
+ else if (gpio_direction_output(cs_gpio, 1))
+ dev_err(&adev->dev,
+ "could set gpio %d as output\n",
+ cs_gpio);
+ }
+ }
+#else
+ for (i = 0; i < num_cs; i++)
+ pl022->chipselect[i] = -EINVAL;
+#endif

/*
* Supports mode 0-3, loopback, and active low CS. Transfers are
@@ -2130,6 +2204,9 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id)
err_no_ioremap:
amba_release_regions(adev);
err_no_ioregion:
+ #if IS_ENABLED(CONFIG_OF)
+ err_no_gpio:
+ #endif
spi_master_put(master);
err_no_master:
err_no_pdata:
--
1.7.10

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Next message: Luis Henriques: "[Regression] No sound on HP Pavilion dv6, STAC92xx"
Previous message: Rob Herring: "Re: [RFC 2/2] usb: gadget: composite: parse dt overrides"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]