linux/drivers/spi/spi-orion.c
Ken Wilson 23244404e2 spi: orion: Add multiple chip select support to spi-orion
This commit adds support for multiple hardware chip selects to spi-orion.
Different SoCs support different number of chip selects (up to
8 on some platforms). The driver allows up to this number, and it is up
to the implementer to only use the chip selects that are available.

Signed-off-by: Ken Wilson <ken.wilson@opengear.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-16 12:38:54 +00:00

552 lines
13 KiB
C

/*
* Marvell Orion SPI controller driver
*
* Author: Shadi Ammouri <shadi@marvell.com>
* Copyright (C) 2007-2008 Marvell Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/clk.h>
#include <linux/sizes.h>
#include <asm/unaligned.h>
#define DRIVER_NAME "orion_spi"
/* Runtime PM autosuspend timeout: PM is fairly light on this driver */
#define SPI_AUTOSUSPEND_TIMEOUT 200
/* Some SoCs using this driver support up to 8 chip selects.
* It is up to the implementer to only use the chip selects
* that are available.
*/
#define ORION_NUM_CHIPSELECTS 8
#define ORION_SPI_WAIT_RDY_MAX_LOOP 2000 /* in usec */
#define ORION_SPI_IF_CTRL_REG 0x00
#define ORION_SPI_IF_CONFIG_REG 0x04
#define ORION_SPI_DATA_OUT_REG 0x08
#define ORION_SPI_DATA_IN_REG 0x0c
#define ORION_SPI_INT_CAUSE_REG 0x10
#define ORION_SPI_MODE_CPOL (1 << 11)
#define ORION_SPI_MODE_CPHA (1 << 12)
#define ORION_SPI_IF_8_16_BIT_MODE (1 << 5)
#define ORION_SPI_CLK_PRESCALE_MASK 0x1F
#define ARMADA_SPI_CLK_PRESCALE_MASK 0xDF
#define ORION_SPI_MODE_MASK (ORION_SPI_MODE_CPOL | \
ORION_SPI_MODE_CPHA)
#define ORION_SPI_CS_MASK 0x1C
#define ORION_SPI_CS_SHIFT 2
#define ORION_SPI_CS(cs) ((cs << ORION_SPI_CS_SHIFT) & \
ORION_SPI_CS_MASK)
enum orion_spi_type {
ORION_SPI,
ARMADA_SPI,
};
struct orion_spi_dev {
enum orion_spi_type typ;
unsigned int min_divisor;
unsigned int max_divisor;
u32 prescale_mask;
};
struct orion_spi {
struct spi_master *master;
void __iomem *base;
struct clk *clk;
const struct orion_spi_dev *devdata;
};
static inline void __iomem *spi_reg(struct orion_spi *orion_spi, u32 reg)
{
return orion_spi->base + reg;
}
static inline void
orion_spi_setbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
{
void __iomem *reg_addr = spi_reg(orion_spi, reg);
u32 val;
val = readl(reg_addr);
val |= mask;
writel(val, reg_addr);
}
static inline void
orion_spi_clrbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
{
void __iomem *reg_addr = spi_reg(orion_spi, reg);
u32 val;
val = readl(reg_addr);
val &= ~mask;
writel(val, reg_addr);
}
static int orion_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
{
u32 tclk_hz;
u32 rate;
u32 prescale;
u32 reg;
struct orion_spi *orion_spi;
const struct orion_spi_dev *devdata;
orion_spi = spi_master_get_devdata(spi->master);
devdata = orion_spi->devdata;
tclk_hz = clk_get_rate(orion_spi->clk);
if (devdata->typ == ARMADA_SPI) {
unsigned int clk, spr, sppr, sppr2, err;
unsigned int best_spr, best_sppr, best_err;
best_err = speed;
best_spr = 0;
best_sppr = 0;
/* Iterate over the valid range looking for best fit */
for (sppr = 0; sppr < 8; sppr++) {
sppr2 = 0x1 << sppr;
spr = tclk_hz / sppr2;
spr = DIV_ROUND_UP(spr, speed);
if ((spr == 0) || (spr > 15))
continue;
clk = tclk_hz / (spr * sppr2);
err = speed - clk;
if (err < best_err) {
best_spr = spr;
best_sppr = sppr;
best_err = err;
}
}
if ((best_sppr == 0) && (best_spr == 0))
return -EINVAL;
prescale = ((best_sppr & 0x6) << 5) |
((best_sppr & 0x1) << 4) | best_spr;
} else {
/*
* the supported rates are: 4,6,8...30
* round up as we look for equal or less speed
*/
rate = DIV_ROUND_UP(tclk_hz, speed);
rate = roundup(rate, 2);
/* check if requested speed is too small */
if (rate > 30)
return -EINVAL;
if (rate < 4)
rate = 4;
/* Convert the rate to SPI clock divisor value. */
prescale = 0x10 + rate/2;
}
reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
reg = ((reg & ~devdata->prescale_mask) | prescale);
writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
return 0;
}
static void
orion_spi_mode_set(struct spi_device *spi)
{
u32 reg;
struct orion_spi *orion_spi;
orion_spi = spi_master_get_devdata(spi->master);
reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
reg &= ~ORION_SPI_MODE_MASK;
if (spi->mode & SPI_CPOL)
reg |= ORION_SPI_MODE_CPOL;
if (spi->mode & SPI_CPHA)
reg |= ORION_SPI_MODE_CPHA;
writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
}
/*
* called only when no transfer is active on the bus
*/
static int
orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
{
struct orion_spi *orion_spi;
unsigned int speed = spi->max_speed_hz;
unsigned int bits_per_word = spi->bits_per_word;
int rc;
orion_spi = spi_master_get_devdata(spi->master);
if ((t != NULL) && t->speed_hz)
speed = t->speed_hz;
if ((t != NULL) && t->bits_per_word)
bits_per_word = t->bits_per_word;
orion_spi_mode_set(spi);
rc = orion_spi_baudrate_set(spi, speed);
if (rc)
return rc;
if (bits_per_word == 16)
orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
ORION_SPI_IF_8_16_BIT_MODE);
else
orion_spi_clrbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
ORION_SPI_IF_8_16_BIT_MODE);
return 0;
}
static void orion_spi_set_cs(struct spi_device *spi, bool enable)
{
struct orion_spi *orion_spi;
orion_spi = spi_master_get_devdata(spi->master);
orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, ORION_SPI_CS_MASK);
orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG,
ORION_SPI_CS(spi->chip_select));
/* Chip select logic is inverted from spi_set_cs */
if (!enable)
orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
else
orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
}
static inline int orion_spi_wait_till_ready(struct orion_spi *orion_spi)
{
int i;
for (i = 0; i < ORION_SPI_WAIT_RDY_MAX_LOOP; i++) {
if (readl(spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG)))
return 1;
udelay(1);
}
return -1;
}
static inline int
orion_spi_write_read_8bit(struct spi_device *spi,
const u8 **tx_buf, u8 **rx_buf)
{
void __iomem *tx_reg, *rx_reg, *int_reg;
struct orion_spi *orion_spi;
orion_spi = spi_master_get_devdata(spi->master);
tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
/* clear the interrupt cause register */
writel(0x0, int_reg);
if (tx_buf && *tx_buf)
writel(*(*tx_buf)++, tx_reg);
else
writel(0, tx_reg);
if (orion_spi_wait_till_ready(orion_spi) < 0) {
dev_err(&spi->dev, "TXS timed out\n");
return -1;
}
if (rx_buf && *rx_buf)
*(*rx_buf)++ = readl(rx_reg);
return 1;
}
static inline int
orion_spi_write_read_16bit(struct spi_device *spi,
const u16 **tx_buf, u16 **rx_buf)
{
void __iomem *tx_reg, *rx_reg, *int_reg;
struct orion_spi *orion_spi;
orion_spi = spi_master_get_devdata(spi->master);
tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
/* clear the interrupt cause register */
writel(0x0, int_reg);
if (tx_buf && *tx_buf)
writel(__cpu_to_le16(get_unaligned((*tx_buf)++)), tx_reg);
else
writel(0, tx_reg);
if (orion_spi_wait_till_ready(orion_spi) < 0) {
dev_err(&spi->dev, "TXS timed out\n");
return -1;
}
if (rx_buf && *rx_buf)
put_unaligned(__le16_to_cpu(readl(rx_reg)), (*rx_buf)++);
return 1;
}
static unsigned int
orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
{
unsigned int count;
int word_len;
word_len = spi->bits_per_word;
count = xfer->len;
if (word_len == 8) {
const u8 *tx = xfer->tx_buf;
u8 *rx = xfer->rx_buf;
do {
if (orion_spi_write_read_8bit(spi, &tx, &rx) < 0)
goto out;
count--;
} while (count);
} else if (word_len == 16) {
const u16 *tx = xfer->tx_buf;
u16 *rx = xfer->rx_buf;
do {
if (orion_spi_write_read_16bit(spi, &tx, &rx) < 0)
goto out;
count -= 2;
} while (count);
}
out:
return xfer->len - count;
}
static int orion_spi_transfer_one(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *t)
{
int status = 0;
status = orion_spi_setup_transfer(spi, t);
if (status < 0)
return status;
if (t->len)
orion_spi_write_read(spi, t);
return status;
}
static int orion_spi_setup(struct spi_device *spi)
{
return orion_spi_setup_transfer(spi, NULL);
}
static int orion_spi_reset(struct orion_spi *orion_spi)
{
/* Verify that the CS is deasserted */
orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
return 0;
}
static const struct orion_spi_dev orion_spi_dev_data = {
.typ = ORION_SPI,
.min_divisor = 4,
.max_divisor = 30,
.prescale_mask = ORION_SPI_CLK_PRESCALE_MASK,
};
static const struct orion_spi_dev armada_spi_dev_data = {
.typ = ARMADA_SPI,
.min_divisor = 1,
.max_divisor = 1920,
.prescale_mask = ARMADA_SPI_CLK_PRESCALE_MASK,
};
static const struct of_device_id orion_spi_of_match_table[] = {
{ .compatible = "marvell,orion-spi", .data = &orion_spi_dev_data, },
{ .compatible = "marvell,armada-370-spi", .data = &armada_spi_dev_data, },
{}
};
MODULE_DEVICE_TABLE(of, orion_spi_of_match_table);
static int orion_spi_probe(struct platform_device *pdev)
{
const struct of_device_id *of_id;
const struct orion_spi_dev *devdata;
struct spi_master *master;
struct orion_spi *spi;
struct resource *r;
unsigned long tclk_hz;
int status = 0;
master = spi_alloc_master(&pdev->dev, sizeof(*spi));
if (master == NULL) {
dev_dbg(&pdev->dev, "master allocation failed\n");
return -ENOMEM;
}
if (pdev->id != -1)
master->bus_num = pdev->id;
if (pdev->dev.of_node) {
u32 cell_index;
if (!of_property_read_u32(pdev->dev.of_node, "cell-index",
&cell_index))
master->bus_num = cell_index;
}
/* we support only mode 0, and no options */
master->mode_bits = SPI_CPHA | SPI_CPOL;
master->set_cs = orion_spi_set_cs;
master->transfer_one = orion_spi_transfer_one;
master->num_chipselect = ORION_NUM_CHIPSELECTS;
master->setup = orion_spi_setup;
master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
master->auto_runtime_pm = true;
platform_set_drvdata(pdev, master);
spi = spi_master_get_devdata(master);
spi->master = master;
of_id = of_match_device(orion_spi_of_match_table, &pdev->dev);
devdata = (of_id) ? of_id->data : &orion_spi_dev_data;
spi->devdata = devdata;
spi->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(spi->clk)) {
status = PTR_ERR(spi->clk);
goto out;
}
status = clk_prepare_enable(spi->clk);
if (status)
goto out;
tclk_hz = clk_get_rate(spi->clk);
master->max_speed_hz = DIV_ROUND_UP(tclk_hz, devdata->min_divisor);
master->min_speed_hz = DIV_ROUND_UP(tclk_hz, devdata->max_divisor);
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
spi->base = devm_ioremap_resource(&pdev->dev, r);
if (IS_ERR(spi->base)) {
status = PTR_ERR(spi->base);
goto out_rel_clk;
}
pm_runtime_set_active(&pdev->dev);
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
pm_runtime_enable(&pdev->dev);
status = orion_spi_reset(spi);
if (status < 0)
goto out_rel_pm;
pm_runtime_mark_last_busy(&pdev->dev);
pm_runtime_put_autosuspend(&pdev->dev);
master->dev.of_node = pdev->dev.of_node;
status = spi_register_master(master);
if (status < 0)
goto out_rel_pm;
return status;
out_rel_pm:
pm_runtime_disable(&pdev->dev);
out_rel_clk:
clk_disable_unprepare(spi->clk);
out:
spi_master_put(master);
return status;
}
static int orion_spi_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct orion_spi *spi = spi_master_get_devdata(master);
pm_runtime_get_sync(&pdev->dev);
clk_disable_unprepare(spi->clk);
spi_unregister_master(master);
pm_runtime_disable(&pdev->dev);
return 0;
}
MODULE_ALIAS("platform:" DRIVER_NAME);
#ifdef CONFIG_PM
static int orion_spi_runtime_suspend(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct orion_spi *spi = spi_master_get_devdata(master);
clk_disable_unprepare(spi->clk);
return 0;
}
static int orion_spi_runtime_resume(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct orion_spi *spi = spi_master_get_devdata(master);
return clk_prepare_enable(spi->clk);
}
#endif
static const struct dev_pm_ops orion_spi_pm_ops = {
SET_RUNTIME_PM_OPS(orion_spi_runtime_suspend,
orion_spi_runtime_resume,
NULL)
};
static struct platform_driver orion_spi_driver = {
.driver = {
.name = DRIVER_NAME,
.pm = &orion_spi_pm_ops,
.of_match_table = of_match_ptr(orion_spi_of_match_table),
},
.probe = orion_spi_probe,
.remove = orion_spi_remove,
};
module_platform_driver(orion_spi_driver);
MODULE_DESCRIPTION("Orion SPI driver");
MODULE_AUTHOR("Shadi Ammouri <shadi@marvell.com>");
MODULE_LICENSE("GPL");