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spi: McSPI off-mode support
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Add context save/restore feature to McSPI driver.

Signed-off-by: Hemanth V <hemanthv@ti.com>
Reviewed-by: Aaro Koskinen <Aaro.Koskinen@nokia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Hemanth V authored and Linus Torvalds committed Sep 23, 2009
1 parent 0644c48 commit a41ae1a
Showing 1 changed file with 100 additions and 34 deletions.
134 changes: 100 additions & 34 deletions drivers/spi/omap2_mcspi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,9 @@

#define OMAP2_MCSPI_MAX_FREQ 48000000

/* OMAP2 has 3 SPI controllers, while OMAP3 has 4 */
#define OMAP2_MCSPI_MAX_CTRL 4

#define OMAP2_MCSPI_REVISION 0x00
#define OMAP2_MCSPI_SYSCONFIG 0x10
#define OMAP2_MCSPI_SYSSTATUS 0x14
Expand Down Expand Up @@ -131,8 +134,21 @@ struct omap2_mcspi_cs {
void __iomem *base;
unsigned long phys;
int word_len;
/* Context save and restore shadow register */
u32 chconf0;
};

/* used for context save and restore, structure members to be updated whenever
* corresponding registers are modified.
*/
struct omap2_mcspi_regs {
u32 sysconfig;
u32 modulctrl;
u32 wakeupenable;
};

static struct omap2_mcspi_regs omap2_mcspi_ctx[OMAP2_MCSPI_MAX_CTRL];

static struct workqueue_struct *omap2_mcspi_wq;

#define MOD_REG_BIT(val, mask, set) do { \
Expand Down Expand Up @@ -172,20 +188,35 @@ static inline u32 mcspi_read_cs_reg(const struct spi_device *spi, int idx)
return __raw_readl(cs->base + idx);
}

static inline u32 mcspi_cached_chconf0(const struct spi_device *spi)
{
struct omap2_mcspi_cs *cs = spi->controller_state;

return cs->chconf0;
}

static inline void mcspi_write_chconf0(const struct spi_device *spi, u32 val)
{
struct omap2_mcspi_cs *cs = spi->controller_state;

cs->chconf0 = val;
mcspi_write_cs_reg(spi, OMAP2_MCSPI_CHCONF0, val);
}

static void omap2_mcspi_set_dma_req(const struct spi_device *spi,
int is_read, int enable)
{
u32 l, rw;

l = mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHCONF0);
l = mcspi_cached_chconf0(spi);

if (is_read) /* 1 is read, 0 write */
rw = OMAP2_MCSPI_CHCONF_DMAR;
else
rw = OMAP2_MCSPI_CHCONF_DMAW;

MOD_REG_BIT(l, rw, enable);
mcspi_write_cs_reg(spi, OMAP2_MCSPI_CHCONF0, l);
mcspi_write_chconf0(spi, l);
}

static void omap2_mcspi_set_enable(const struct spi_device *spi, int enable)
Expand All @@ -200,9 +231,9 @@ static void omap2_mcspi_force_cs(struct spi_device *spi, int cs_active)
{
u32 l;

l = mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHCONF0);
l = mcspi_cached_chconf0(spi);
MOD_REG_BIT(l, OMAP2_MCSPI_CHCONF_FORCE, cs_active);
mcspi_write_cs_reg(spi, OMAP2_MCSPI_CHCONF0, l);
mcspi_write_chconf0(spi, l);
}

static void omap2_mcspi_set_master_mode(struct spi_master *master)
Expand All @@ -217,6 +248,41 @@ static void omap2_mcspi_set_master_mode(struct spi_master *master)
MOD_REG_BIT(l, OMAP2_MCSPI_MODULCTRL_MS, 0);
MOD_REG_BIT(l, OMAP2_MCSPI_MODULCTRL_SINGLE, 1);
mcspi_write_reg(master, OMAP2_MCSPI_MODULCTRL, l);

omap2_mcspi_ctx[master->bus_num - 1].modulctrl = l;
}

static void omap2_mcspi_restore_ctx(struct omap2_mcspi *mcspi)
{
struct spi_master *spi_cntrl;
spi_cntrl = mcspi->master;

/* McSPI: context restore */
mcspi_write_reg(spi_cntrl, OMAP2_MCSPI_MODULCTRL,
omap2_mcspi_ctx[spi_cntrl->bus_num - 1].modulctrl);

mcspi_write_reg(spi_cntrl, OMAP2_MCSPI_SYSCONFIG,
omap2_mcspi_ctx[spi_cntrl->bus_num - 1].sysconfig);

mcspi_write_reg(spi_cntrl, OMAP2_MCSPI_WAKEUPENABLE,
omap2_mcspi_ctx[spi_cntrl->bus_num - 1].wakeupenable);
}
static void omap2_mcspi_disable_clocks(struct omap2_mcspi *mcspi)
{
clk_disable(mcspi->ick);
clk_disable(mcspi->fck);
}

static int omap2_mcspi_enable_clocks(struct omap2_mcspi *mcspi)
{
if (clk_enable(mcspi->ick))
return -ENODEV;
if (clk_enable(mcspi->fck))
return -ENODEV;

omap2_mcspi_restore_ctx(mcspi);

return 0;
}

static unsigned
Expand Down Expand Up @@ -357,7 +423,7 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
c = count;
word_len = cs->word_len;

l = mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHCONF0);
l = mcspi_cached_chconf0(spi);
l &= ~OMAP2_MCSPI_CHCONF_TRM_MASK;

/* We store the pre-calculated register addresses on stack to speed
Expand Down Expand Up @@ -397,8 +463,7 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
* more word i/o: switch to rx+tx
*/
if (c == 0 && tx == NULL)
mcspi_write_cs_reg(spi,
OMAP2_MCSPI_CHCONF0, l);
mcspi_write_chconf0(spi, l);
*rx++ = __raw_readl(rx_reg);
#ifdef VERBOSE
dev_dbg(&spi->dev, "read-%d %02x\n",
Expand Down Expand Up @@ -436,8 +501,7 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
* more word i/o: switch to rx+tx
*/
if (c == 0 && tx == NULL)
mcspi_write_cs_reg(spi,
OMAP2_MCSPI_CHCONF0, l);
mcspi_write_chconf0(spi, l);
*rx++ = __raw_readl(rx_reg);
#ifdef VERBOSE
dev_dbg(&spi->dev, "read-%d %04x\n",
Expand Down Expand Up @@ -475,8 +539,7 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
* more word i/o: switch to rx+tx
*/
if (c == 0 && tx == NULL)
mcspi_write_cs_reg(spi,
OMAP2_MCSPI_CHCONF0, l);
mcspi_write_chconf0(spi, l);
*rx++ = __raw_readl(rx_reg);
#ifdef VERBOSE
dev_dbg(&spi->dev, "read-%d %04x\n",
Expand Down Expand Up @@ -505,10 +568,12 @@ static int omap2_mcspi_setup_transfer(struct spi_device *spi,
{
struct omap2_mcspi_cs *cs = spi->controller_state;
struct omap2_mcspi *mcspi;
struct spi_master *spi_cntrl;
u32 l = 0, div = 0;
u8 word_len = spi->bits_per_word;

mcspi = spi_master_get_devdata(spi->master);
spi_cntrl = mcspi->master;

if (t != NULL && t->bits_per_word)
word_len = t->bits_per_word;
Expand All @@ -522,7 +587,7 @@ static int omap2_mcspi_setup_transfer(struct spi_device *spi,
} else
div = 15;

l = mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHCONF0);
l = mcspi_cached_chconf0(spi);

/* standard 4-wire master mode: SCK, MOSI/out, MISO/in, nCS
* REVISIT: this controller could support SPI_3WIRE mode.
Expand Down Expand Up @@ -554,7 +619,7 @@ static int omap2_mcspi_setup_transfer(struct spi_device *spi,
else
l &= ~OMAP2_MCSPI_CHCONF_PHA;

mcspi_write_cs_reg(spi, OMAP2_MCSPI_CHCONF0, l);
mcspi_write_chconf0(spi, l);

dev_dbg(&spi->dev, "setup: speed %d, sample %s edge, clk %s\n",
OMAP2_MCSPI_MAX_FREQ / (1 << div),
Expand Down Expand Up @@ -647,6 +712,7 @@ static int omap2_mcspi_setup(struct spi_device *spi)
return -ENOMEM;
cs->base = mcspi->base + spi->chip_select * 0x14;
cs->phys = mcspi->phys + spi->chip_select * 0x14;
cs->chconf0 = 0;
spi->controller_state = cs;
}

Expand All @@ -657,11 +723,11 @@ static int omap2_mcspi_setup(struct spi_device *spi)
return ret;
}

clk_enable(mcspi->ick);
clk_enable(mcspi->fck);
if (omap2_mcspi_enable_clocks(mcspi))
return -ENODEV;

ret = omap2_mcspi_setup_transfer(spi, NULL);
clk_disable(mcspi->fck);
clk_disable(mcspi->ick);
omap2_mcspi_disable_clocks(mcspi);

return ret;
}
Expand Down Expand Up @@ -693,8 +759,8 @@ static void omap2_mcspi_work(struct work_struct *work)
mcspi = container_of(work, struct omap2_mcspi, work);
spin_lock_irq(&mcspi->lock);

clk_enable(mcspi->ick);
clk_enable(mcspi->fck);
if (omap2_mcspi_enable_clocks(mcspi))
goto out;

/* We only enable one channel at a time -- the one whose message is
* at the head of the queue -- although this controller would gladly
Expand Down Expand Up @@ -741,13 +807,13 @@ static void omap2_mcspi_work(struct work_struct *work)
cs_active = 1;
}

chconf = mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHCONF0);
chconf = mcspi_cached_chconf0(spi);
chconf &= ~OMAP2_MCSPI_CHCONF_TRM_MASK;
if (t->tx_buf == NULL)
chconf |= OMAP2_MCSPI_CHCONF_TRM_RX_ONLY;
else if (t->rx_buf == NULL)
chconf |= OMAP2_MCSPI_CHCONF_TRM_TX_ONLY;
mcspi_write_cs_reg(spi, OMAP2_MCSPI_CHCONF0, chconf);
mcspi_write_chconf0(spi, chconf);

if (t->len) {
unsigned count;
Expand Down Expand Up @@ -796,9 +862,9 @@ static void omap2_mcspi_work(struct work_struct *work)
spin_lock_irq(&mcspi->lock);
}

clk_disable(mcspi->fck);
clk_disable(mcspi->ick);
omap2_mcspi_disable_clocks(mcspi);

out:
spin_unlock_irq(&mcspi->lock);
}

Expand Down Expand Up @@ -885,27 +951,27 @@ static int __init omap2_mcspi_reset(struct omap2_mcspi *mcspi)
struct spi_master *master = mcspi->master;
u32 tmp;

clk_enable(mcspi->ick);
clk_enable(mcspi->fck);
if (omap2_mcspi_enable_clocks(mcspi))
return -1;

mcspi_write_reg(master, OMAP2_MCSPI_SYSCONFIG,
OMAP2_MCSPI_SYSCONFIG_SOFTRESET);
do {
tmp = mcspi_read_reg(master, OMAP2_MCSPI_SYSSTATUS);
} while (!(tmp & OMAP2_MCSPI_SYSSTATUS_RESETDONE));

mcspi_write_reg(master, OMAP2_MCSPI_SYSCONFIG,
OMAP2_MCSPI_SYSCONFIG_AUTOIDLE |
OMAP2_MCSPI_SYSCONFIG_ENAWAKEUP |
OMAP2_MCSPI_SYSCONFIG_SMARTIDLE);
tmp = OMAP2_MCSPI_SYSCONFIG_AUTOIDLE |
OMAP2_MCSPI_SYSCONFIG_ENAWAKEUP |
OMAP2_MCSPI_SYSCONFIG_SMARTIDLE;
mcspi_write_reg(master, OMAP2_MCSPI_SYSCONFIG, tmp);
omap2_mcspi_ctx[master->bus_num - 1].sysconfig = tmp;

mcspi_write_reg(master, OMAP2_MCSPI_WAKEUPENABLE,
OMAP2_MCSPI_WAKEUPENABLE_WKEN);
tmp = OMAP2_MCSPI_WAKEUPENABLE_WKEN;
mcspi_write_reg(master, OMAP2_MCSPI_WAKEUPENABLE, tmp);
omap2_mcspi_ctx[master->bus_num - 1].wakeupenable = tmp;

omap2_mcspi_set_master_mode(master);

clk_disable(mcspi->fck);
clk_disable(mcspi->ick);
omap2_mcspi_disable_clocks(mcspi);
return 0;
}

Expand Down

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