diff options
| -rw-r--r-- | Documentation/devicetree/bindings/net/ieee802154/at86rf230.txt | 3 | ||||
| -rw-r--r-- | drivers/net/ieee802154/at86rf230.c | 54 | ||||
| -rw-r--r-- | include/linux/spi/at86rf230.h | 1 |
3 files changed, 54 insertions, 4 deletions
diff --git a/Documentation/devicetree/bindings/net/ieee802154/at86rf230.txt b/Documentation/devicetree/bindings/net/ieee802154/at86rf230.txt index d3bbdded4cbe..1ae5100fea14 100644 --- a/Documentation/devicetree/bindings/net/ieee802154/at86rf230.txt +++ b/Documentation/devicetree/bindings/net/ieee802154/at86rf230.txt @@ -11,6 +11,8 @@ Required properties: Optional properties: - reset-gpio: GPIO spec for the rstn pin - sleep-gpio: GPIO spec for the slp_tr pin + - xtal-trim: u8 value for fine tuning the internal capacitance + arrays of xtal pins: 0 = +0 pF, 0xf = +4.5 pF Example: @@ -20,4 +22,5 @@ Example: reg = <0>; interrupts = <19 1>; interrupt-parent = <&gpio3>; + xtal-trim = /bits/ 8 <0x06>; }; diff --git a/drivers/net/ieee802154/at86rf230.c b/drivers/net/ieee802154/at86rf230.c index 9888b7ff24bc..c1323e5cdd0c 100644 --- a/drivers/net/ieee802154/at86rf230.c +++ b/drivers/net/ieee802154/at86rf230.c @@ -1315,7 +1315,7 @@ static struct at86rf2xx_chip_data at86rf212_data = { .get_desense_steps = at86rf212_get_desens_steps }; -static int at86rf230_hw_init(struct at86rf230_local *lp) +static int at86rf230_hw_init(struct at86rf230_local *lp, u8 xtal_trim) { int rc, irq_type, irq_pol = IRQ_ACTIVE_HIGH; unsigned int dvdd; @@ -1362,6 +1362,45 @@ static int at86rf230_hw_init(struct at86rf230_local *lp) usleep_range(lp->data->t_sleep_cycle, lp->data->t_sleep_cycle + 100); + /* xtal_trim value is calculated by: + * CL = 0.5 * (CX + CTRIM + CPAR) + * + * whereas: + * CL = capacitor of used crystal + * CX = connected capacitors at xtal pins + * CPAR = in all at86rf2xx datasheets this is a constant value 3 pF, + * but this is different on each board setup. You need to fine + * tuning this value via CTRIM. + * CTRIM = variable capacitor setting. Resolution is 0.3 pF range is + * 0 pF upto 4.5 pF. + * + * Examples: + * atben transceiver: + * + * CL = 8 pF + * CX = 12 pF + * CPAR = 3 pF (We assume the magic constant from datasheet) + * CTRIM = 0.9 pF + * + * (12+0.9+3)/2 = 7.95 which is nearly at 8 pF + * + * xtal_trim = 0x3 + * + * openlabs transceiver: + * + * CL = 16 pF + * CX = 22 pF + * CPAR = 3 pF (We assume the magic constant from datasheet) + * CTRIM = 4.5 pF + * + * (22+4.5+3)/2 = 14.75 which is the nearest value to 16 pF + * + * xtal_trim = 0xf + */ + rc = at86rf230_write_subreg(lp, SR_XTAL_TRIM, xtal_trim); + if (rc) + return rc; + rc = at86rf230_read_subreg(lp, SR_DVDD_OK, &dvdd); if (rc) return rc; @@ -1378,9 +1417,11 @@ static int at86rf230_hw_init(struct at86rf230_local *lp) } static int -at86rf230_get_pdata(struct spi_device *spi, int *rstn, int *slp_tr) +at86rf230_get_pdata(struct spi_device *spi, int *rstn, int *slp_tr, + u8 *xtal_trim) { struct at86rf230_platform_data *pdata = spi->dev.platform_data; + int ret; if (!IS_ENABLED(CONFIG_OF) || !spi->dev.of_node) { if (!pdata) @@ -1388,11 +1429,15 @@ at86rf230_get_pdata(struct spi_device *spi, int *rstn, int *slp_tr) *rstn = pdata->rstn; *slp_tr = pdata->slp_tr; + *xtal_trim = pdata->xtal_trim; return 0; } *rstn = of_get_named_gpio(spi->dev.of_node, "reset-gpio", 0); *slp_tr = of_get_named_gpio(spi->dev.of_node, "sleep-gpio", 0); + ret = of_property_read_u8(spi->dev.of_node, "xtal-trim", xtal_trim); + if (ret < 0 && ret != -EINVAL) + return ret; return 0; } @@ -1505,13 +1550,14 @@ static int at86rf230_probe(struct spi_device *spi) struct at86rf230_local *lp; unsigned int status; int rc, irq_type, rstn, slp_tr; + u8 xtal_trim; if (!spi->irq) { dev_err(&spi->dev, "no IRQ specified\n"); return -EINVAL; } - rc = at86rf230_get_pdata(spi, &rstn, &slp_tr); + rc = at86rf230_get_pdata(spi, &rstn, &slp_tr, &xtal_trim); if (rc < 0) { dev_err(&spi->dev, "failed to parse platform_data: %d\n", rc); return rc; @@ -1570,7 +1616,7 @@ static int at86rf230_probe(struct spi_device *spi) spi_set_drvdata(spi, lp); - rc = at86rf230_hw_init(lp); + rc = at86rf230_hw_init(lp, xtal_trim); if (rc) goto free_dev; diff --git a/include/linux/spi/at86rf230.h b/include/linux/spi/at86rf230.h index cd519a11c2c6..b63fe6f5fdc8 100644 --- a/include/linux/spi/at86rf230.h +++ b/include/linux/spi/at86rf230.h @@ -22,6 +22,7 @@ struct at86rf230_platform_data { int rstn; int slp_tr; int dig2; + u8 xtal_trim; }; #endif |