When supporting I2C/SPI based on-board PLLs like CDCE949, it is essential that clk->set_rate be able to sleep.
Currently, this is not possible because clk->set_rate is called from within spin-lock in clk_set_rate This patch brings clk->set_rate outside of the spin-lock and lets the individual set_rate implementations achieve serialization through appropiate means. Signed-off-by: Sekhar Nori <[email protected]> --- This patch is a replacement for an earlier patch titled "davinci: clock framework: remove spinlock usage" arch/arm/mach-davinci/cdce949.c | 10 +++++++--- arch/arm/mach-davinci/clock.c | 9 ++++++++- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/arch/arm/mach-davinci/cdce949.c b/arch/arm/mach-davinci/cdce949.c index 6af3289..aec3756 100644 --- a/arch/arm/mach-davinci/cdce949.c +++ b/arch/arm/mach-davinci/cdce949.c @@ -23,6 +23,7 @@ #include "clock.h" static struct i2c_client *cdce_i2c_client; +static DEFINE_MUTEX(cdce_mutex); /* CDCE register descriptor */ struct cdce_reg { @@ -231,16 +232,19 @@ int cdce_set_rate(struct clk *clk, unsigned long rate) if (!regs) return -EINVAL; + mutex_lock(&cdce_mutex); for (i = 0; regs[i].addr; i++) { ret = i2c_smbus_write_byte_data(cdce_i2c_client, regs[i].addr | 0x80, regs[i].val); if (ret) - return ret; + break; } + mutex_unlock(&cdce_mutex); - clk->rate = rate; + if (!ret) + clk->rate = rate; - return 0; + return ret; } static int cdce_probe(struct i2c_client *client, diff --git a/arch/arm/mach-davinci/clock.c b/arch/arm/mach-davinci/clock.c index 79d6ec8..bf6218e 100644 --- a/arch/arm/mach-davinci/clock.c +++ b/arch/arm/mach-davinci/clock.c @@ -125,9 +125,10 @@ int clk_set_rate(struct clk *clk, unsigned long rate) if (clk == NULL || IS_ERR(clk)) return ret; - spin_lock_irqsave(&clockfw_lock, flags); if (clk->set_rate) ret = clk->set_rate(clk, rate); + + spin_lock_irqsave(&clockfw_lock, flags); if (ret == 0) { if (clk->recalc) clk->rate = clk->recalc(clk); @@ -364,6 +365,7 @@ int davinci_set_pllrate(struct pll_data *pll, unsigned int prediv, { u32 ctrl; unsigned int locktime; + unsigned long flags; if (pll->base == NULL) return -EINVAL; @@ -384,6 +386,9 @@ int davinci_set_pllrate(struct pll_data *pll, unsigned int prediv, if (mult) mult = mult - 1; + /* Protect against simultaneous calls to PLL setting seqeunce */ + spin_lock_irqsave(&clockfw_lock, flags); + ctrl = __raw_readl(pll->base + PLLCTL); /* Switch the PLL to bypass mode */ @@ -416,6 +421,8 @@ int davinci_set_pllrate(struct pll_data *pll, unsigned int prediv, ctrl |= PLLCTL_PLLEN; __raw_writel(ctrl, pll->base + PLLCTL); + spin_unlock_irqrestore(&clockfw_lock, flags); + return 0; } EXPORT_SYMBOL(davinci_set_pllrate); -- 1.6.2.4 _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
