On 09/17, Mike Looijmans wrote: > This patch adds the driver and devicetree documentation for the > Silicon Labs SI514 clock generator chip. This is an I2C controlled > oscilator capable of generating clock signals ranging from 100kHz
s/oscilator/oscillator/ > to 250MHz. > > Signed-off-by: Mike Looijmans <mike.looijm...@topic.nl> > --- > diff --git a/Documentation/devicetree/bindings/clock/silabs,si514.txt > b/Documentation/devicetree/bindings/clock/silabs,si514.txt > new file mode 100644 > index 0000000..05964d1 > --- /dev/null > +++ b/Documentation/devicetree/bindings/clock/silabs,si514.txt > @@ -0,0 +1,27 @@ > +Binding for Silicon Labs 514 programmable I2C clock generator. > + > +Reference > +This binding uses the common clock binding[1]. Details about the device can > be > +found in the datasheet[2]. > + > +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt > +[2] Si514 datasheet > + http://www.silabs.com/Support%20Documents/TechnicalDocs/si514.pdf > + > +Required properties: > + - compatible: Shall be "silabs,si514" > + - reg: I2C device address. > + - #clock-cells: From common clock bindings: Shall be 0. > + > +Optional properties: > + - clock-output-names: From common clock bindings. Recommended to be "si514". > + - clock-frequency: Output frequency to generate. This defines the output > + frequency set during boot. It can be reprogrammed during > + runtime through the common clock framework. Can we use assigned clock rates instead of this property? > + > +Example: > + si514: clock-generator@55 { > + reg = <0x55>; > + #clock-cells = <0>; > + compatible = "silabs,si514"; > + }; > diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig > index 42f7120..6ac7deb5 100644 > --- a/drivers/clk/Kconfig > +++ b/drivers/clk/Kconfig > @@ -68,6 +68,16 @@ config COMMON_CLK_SI5351 > This driver supports Silicon Labs 5351A/B/C programmable clock > generators. > > +config COMMON_CLK_SI514 > + tristate "Clock driver for SiLabs 514 devices" > + depends on I2C > + depends on OF It actually depends on this to build? > + select REGMAP_I2C > + help > + ---help--- > + This driver supports the Silicon Labs 514 programmable clock > + generator. > + > config COMMON_CLK_SI570 > tristate "Clock driver for SiLabs 570 and compatible devices" > depends on I2C > diff --git a/drivers/clk/clk-si514.c b/drivers/clk/clk-si514.c > new file mode 100644 > index 0000000..ca70818 > --- /dev/null > +++ b/drivers/clk/clk-si514.c > @@ -0,0 +1,393 @@ > + > +#include <linux/clk-provider.h> I'd expect some sort of linux/clk.h include here if we're using clk APIs. > +#include <linux/delay.h> > +#include <linux/module.h> > +#include <linux/i2c.h> > +#include <linux/regmap.h> > +#include <linux/slab.h> [...] > + > +/* Program clock settings into hardware */ This comment is useless. > +static int si514_set_muldiv(struct clk_si514 *data, > + struct clk_si514_muldiv *settings) > +{ > + u8 lp; > + u8 reg[7]; > + int err; > + > + /* Calculate LP1/LP2 according to table 13 in the datasheet */ > + /* 65.259980246 */ > + if ((settings->m_int < 65) || > + ((settings->m_int == 65) && (settings->m_frac <= 139575831))) > + lp = 0x22; > + /* 67.859763463 */ > + else if ((settings->m_int < 67) || > + ((settings->m_int == 67) && (settings->m_frac <= 461581994))) > + lp = 0x23; > + /* 72.937624981 */ > + else if ((settings->m_int < 72) || > + ((settings->m_int == 72) && (settings->m_frac <= 503383578))) > + lp = 0x33; > + /* 75.843265046 */ > + else if ((settings->m_int < 75) || > + ((settings->m_int == 75) && (settings->m_frac <= 452724474))) > + lp = 0x34; Drop the extra parenthesis on these if statements. > + else > + lp = 0x44; > + > + err = regmap_write(data->regmap, SI514_REG_LP, lp); > + if (err < 0) > + return err; > + > + reg[0] = settings->m_frac & 0xff; > + reg[1] = (settings->m_frac >> 8) & 0xff; > + reg[2] = (settings->m_frac >> 16) & 0xff; > + reg[3] = ((settings->m_frac >> 24) | (settings->m_int << 5)) & 0xff; > + reg[4] = (settings->m_int >> 3) & 0xff; > + reg[5] = (settings->hs_div) & 0xff; > + reg[6] = (((settings->hs_div) >> 8) | > + (settings->ls_div_bits << 4)) & 0xff; The & 0xff part is redundant. Assignment truncates for us. > + > + err = regmap_bulk_write(data->regmap, SI514_REG_HS_DIV, reg + 5, 2); > + if (err < 0) > + return err; > + /* Writing to SI514_REG_M_INT_FRAC triggers the clock change, so that > + * must be written last */ Please fix multi-line commenting style. > + return regmap_bulk_write(data->regmap, SI514_REG_M_FRAC1, reg, 5); > +} > + > +/* Calculate divider settings for a given frequency */ > +static int si514_calc_muldiv(struct clk_si514_muldiv *settings, > + unsigned long frequency) > +{ > + u64 m; > + u32 ls_freq; > + u32 tmp; > + u8 res; > + > + if ((frequency < SI514_MIN_FREQ) || (frequency > SI514_MAX_FREQ)) > + return -EINVAL; > + > + /* Determine the minimum value of LS_DIV and resulting target freq. */ > + ls_freq = frequency; > + if (frequency >= (FVCO_MIN / HS_DIV_MAX)) > + settings->ls_div_bits = 0; > + else { > + res = 1; > + tmp = 2 * HS_DIV_MAX; > + while (tmp <= (HS_DIV_MAX*32)) { Please add some space here between HS_DIV_MAX and 32. > + if ((frequency * tmp) >= FVCO_MIN) > + break; /* We're done */ Yep, that's what break in a loop usually means. > + ++res; > + tmp <<= 1; > + } > + settings->ls_div_bits = res; > + ls_freq = frequency << res; > + } > + > + /* Determine minimum HS_DIV, round up to even number */ > + settings->hs_div = DIV_ROUND_UP(FVCO_MIN >> 1, ls_freq) << 1; > + > + /* M = LS_DIV x HS_DIV x frequency / F_XO (in fixed-point) */ > + m = ((u64)(ls_freq * settings->hs_div) << 29) + (FXO/2); > + do_div(m, FXO); > + settings->m_frac = (u32)m & (BIT(29) - 1); > + settings->m_int = (u32)(m >> 29); > + > + return 0; > +} > + > +/* Calculate resulting frequency given the register settings */ > +static unsigned long si514_calc_rate(struct clk_si514_muldiv *settings) > +{ > + u64 m = settings->m_frac | ((u64)settings->m_int << 29); > + > + return ((u32)(((m * FXO) + (FXO/2)) >> 29)) / Please add space after / > + (settings->hs_div * BIT(settings->ls_div_bits)); And drop the extra parenthesis. It would be nice if we didn't do it all in one line too. Use some local variables. > +} > + [...] > + > + err = si514_calc_muldiv(&settings, rate); > + if (err) > + return err; > + > + return si514_calc_rate(&settings); > +} > + > +/* Update output frequency for big frequency changes (> 1000 ppm). > + * The chip supports <1000ppm changes "on the fly", we haven't implemented > + * that here. */ Please fix comment style. > +static int si514_set_rate(struct clk_hw *hw, unsigned long rate, > + unsigned long parent_rate) > +{ > + struct clk_si514 *data = to_clk_si514(hw); > + struct clk_si514_muldiv settings; > + int err; > + > + err = si514_calc_muldiv(&settings, rate); > + if (err) > + return err; > + > + si514_enable_output(data, false); > + > + err = si514_set_muldiv(data, &settings); > + if (err < 0) > + return err; /* Undefined state now, best to leave disabled */ > + > + /* Trigger calibration */ > + err = regmap_write(data->regmap, SI514_REG_CONTROL, SI514_CONTROL_FCAL); > + > + /* Applying a new frequency can take up to 10ms */ > + usleep_range(10000, 12000); > + > + si514_enable_output(data, true); > + Should we enable if regmap_write() failed? > + return err; > +} > + > +static const struct clk_ops si514_clk_ops = { > + .recalc_rate = si514_recalc_rate, > + .round_rate = si514_round_rate, > + .set_rate = si514_set_rate, > +}; > + > +static struct regmap_config si514_regmap_config = { const? > + } > + } > + > + /* Display a message indicating that we've successfully registered */ > + dev_info(&client->dev, "registered, current frequency %lu Hz\n", > + clk_get_rate(clk)); Please remove this. > + > + return 0; > +} > + -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
