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linux/drivers/spi/spi-orion.c
Gregory CLEMENT 4dacccfac6 spi: orion: Fix extended baud rates for each Armada SoCs 
The commit df59fa7f4b "spi: orion: support armada extended baud
rates" made the assumptions that all the Armada SoCs supported the
same maximum frequency. However, according the hardware datasheet, the
maximum frequency supported by the Armada 370 SoC is tclk/4, for the
Armada XP, Armada 38x and Armada 39x SoCs the limitation is 50MHz and
for the Armada 375 it is tclk/15.

This patch introduces new compatible strings to handle all these
case. In order to be future proof a compatible was created for each
SoC even if currently some SoCs seem using the same IP.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-05-27 18:44:57 +01:00

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/*
* 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;
/*
* min_divisor and max_hz should be exclusive, the only we can
* have both is for managing the armada-370-spi case with old
* device tree
*/
unsigned long max_hz;
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_370_spi_dev_data = {
.typ = ARMADA_SPI,
.min_divisor = 4,
.max_divisor = 1920,
.max_hz = 50000000,
.prescale_mask = ARMADA_SPI_CLK_PRESCALE_MASK,
};
static const struct orion_spi_dev armada_xp_spi_dev_data = {
.typ = ARMADA_SPI,
.max_hz = 50000000,
.max_divisor = 1920,
.prescale_mask = ARMADA_SPI_CLK_PRESCALE_MASK,
};
static const struct orion_spi_dev armada_375_spi_dev_data = {
.typ = ARMADA_SPI,
.min_divisor = 15,
.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_370_spi_dev_data,
},
{
.compatible = "marvell,armada-375-spi",
.data = &armada_375_spi_dev_data,
},
{
.compatible = "marvell,armada-380-spi",
.data = &armada_xp_spi_dev_data,
},
{
.compatible = "marvell,armada-390-spi",
.data = &armada_xp_spi_dev_data,
},
{
.compatible = "marvell,armada-xp-spi",
.data = &armada_xp_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);
/*
* With old device tree, armada-370-spi could be used with
* Armada XP, however for this SoC the maximum frequency is
* 50MHz instead of tclk/4. On Armada 370, tclk cannot be
* higher than 200MHz. So, in order to be able to handle both
* SoCs, we can take the minimum of 50MHz and tclk/4.
*/
if (of_device_is_compatible(pdev->dev.of_node,
"marvell,armada-370-spi"))
master->max_speed_hz = min(devdata->max_hz,
DIV_ROUND_UP(tclk_hz, devdata->min_divisor));
else if (devdata->min_divisor)
master->max_speed_hz =
DIV_ROUND_UP(tclk_hz, devdata->min_divisor);
else
master->max_speed_hz = devdata->max_hz;
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");
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