From 022dcdf083d67db34f5237369d3501ca5708d8eb Mon Sep 17 00:00:00 2001 From: Axel Lin Date: Mon, 19 Mar 2012 10:55:24 +0800 Subject: [PATCH] regulator: pcf50633: Don't write to reserved bits of AUTO output voltage select register MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The datasheet says 00000000 to 00101110 are reserved, and the min value of the voltage setting is 1.8 V. Thus don't write 0 to AUTO output voltage select register (address 1Ah). Table 50. AUTOOUT - AUTO output voltage select register (address 1Ah) bit description[1] Bit Symbol Access Description 7:0 auto_out R/W VO(prog) = 0.625 + auto_out × 0.025 V eg. 00000000 to 00101110: reserved 00101111: 1.8 V (min) 01010011: 2.7 V 01101010: 3.275 V 01101011: 3.300 V 01101100: 3.325 V 01111111 : 3.800 V (max) ..... ..... 11111110 : 3.800 V 11111111 : 3.800 V This patch also fixes a bug in pcf50633_regulator_list_voltage: In regulator core _regulator_do_set_voltage function: if (rdev->desc->ops->set_voltage) { ret = rdev->desc->ops->set_voltage(rdev, min_uV, max_uV, &selector); if (rdev->desc->ops->list_voltage) selector = rdev->desc->ops->list_voltage(rdev, selector); else selector = -1; The list_voltage call here takes the selector got from set_voltage callback. Thus adding 0x2f to the index in pcf50633_regulator_list_voltage looks wrong to me. e.g. If min_uV < 1.8V, pcf50633_regulator_set_voltage sets 0 to selector. For this case, adding 0x2f to the index in pcf50633_regulator_list_voltage is correct. However, if min_uV == 1.8V, pcf50633_regulator_set_voltage sets 0x2f to selector. Adding 0x2f to the index in pcf50633_regulator_list_voltage in this case is wrong. What this patch does is: The minimal voltage setting for AUTOOUT is 0x2f. Thus for the case min_uV < 1.8, set the voltage setting to 1.8V by writting 0x2f to AUTOOUT register and set selector = 0x2f. So we don't write the rserved range to AUTOOUT register. Which means the possible range of AUTOOUT register value is 0x2f ~ 0xff. We have no problem in regulator_get_voltage. Since we won't write 0~0x2e to AUTOOUT register, we have no problem converting the bits we read to voltage. The equation in auto_voltage_value works fine. For list_voltage, we need to take into account the case selector is 0 ~ 0x2e because the regulator core assumes the selector is starting from 0. This patch returns 0 for the cases selector is 0 ~ 0x2e, which means "this selector code can't be used on this system". The regulator core iterates from 0 to n_voltages to find the small voltage in the specific range. The n_voltages settings for AUTOOUT should be 128 now, including the reserved range of AUTOOUT. Signed-off-by: Axel Lin Acked-by: Lars-Peter Clausen Signed-off-by: Mark Brown --- drivers/regulator/pcf50633-regulator.c | 22 ++++++---------------- 1 file changed, 6 insertions(+), 16 deletions(-) diff --git a/drivers/regulator/pcf50633-regulator.c b/drivers/regulator/pcf50633-regulator.c index 6db46c632f13..c05b5d12b2ca 100644 --- a/drivers/regulator/pcf50633-regulator.c +++ b/drivers/regulator/pcf50633-regulator.c @@ -52,7 +52,7 @@ static const u8 pcf50633_regulator_registers[PCF50633_NUM_REGULATORS] = { static u8 auto_voltage_bits(unsigned int millivolts) { if (millivolts < 1800) - return 0; + return 0x2f; if (millivolts > 3800) return 0xff; @@ -87,6 +87,9 @@ static u8 ldo_voltage_bits(unsigned int millivolts) /* Obtain voltage value from bits */ static unsigned int auto_voltage_value(u8 bits) { + /* AUTOOUT: 00000000 to 00101110 are reserved. + * Return 0 for bits in reserved range, which means this selector code + * can't be used on this system */ if (bits < 0x2f) return 0; @@ -208,20 +211,7 @@ static int pcf50633_regulator_get_voltage(struct regulator_dev *rdev) static int pcf50633_regulator_list_voltage(struct regulator_dev *rdev, unsigned int index) { - struct pcf50633 *pcf; - int regulator_id; - - pcf = rdev_get_drvdata(rdev); - - regulator_id = rdev_get_id(rdev); - - switch (regulator_id) { - case PCF50633_REGULATOR_AUTO: - index += 0x2f; - break; - default: - break; - } + int regulator_id = rdev_get_id(rdev); return pcf50633_regulator_voltage_value(regulator_id, index); } @@ -287,7 +277,7 @@ static struct regulator_ops pcf50633_regulator_ops = { static struct regulator_desc regulators[] = { [PCF50633_REGULATOR_AUTO] = - PCF50633_REGULATOR("auto", PCF50633_REGULATOR_AUTO, 81), + PCF50633_REGULATOR("auto", PCF50633_REGULATOR_AUTO, 128), [PCF50633_REGULATOR_DOWN1] = PCF50633_REGULATOR("down1", PCF50633_REGULATOR_DOWN1, 96), [PCF50633_REGULATOR_DOWN2] = -- 2.30.2