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author | Russell King <rmk+kernel@armlinux.org.uk> | 2018-11-28 13:57:23 +0000 |
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committer | Russell King <rmk+kernel@armlinux.org.uk> | 2018-12-04 22:37:38 +0000 |
commit | bebdf98a786292501e4f7d596ffe61faaf3a3aca (patch) | |
tree | f65dbd50a6707f012a2f5e5652451273dc2ac421 /drivers/pcmcia/max1600.c | |
parent | d66a2fb8d7b0a103f5d6884ff9db895959bf0924 (diff) | |
download | blackbird-op-linux-bebdf98a786292501e4f7d596ffe61faaf3a3aca.tar.gz blackbird-op-linux-bebdf98a786292501e4f7d596ffe61faaf3a3aca.zip |
pcmcia: add MAX1600 library
Add a library for the MAX1600 PCMCIA power switch device. This is a
dual-channel device, controlled via four GPIO signals per channel.
Two signals control the Vcc output, and two control the Vpp output.
Acked-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'drivers/pcmcia/max1600.c')
-rw-r--r-- | drivers/pcmcia/max1600.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/drivers/pcmcia/max1600.c b/drivers/pcmcia/max1600.c new file mode 100644 index 000000000000..379875a5e7cd --- /dev/null +++ b/drivers/pcmcia/max1600.c @@ -0,0 +1,122 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * MAX1600 PCMCIA power switch library + * + * Copyright (C) 2016 Russell King + */ +#include <linux/device.h> +#include <linux/module.h> +#include <linux/gpio/consumer.h> +#include <linux/slab.h> +#include "max1600.h" + +static const char *max1600_gpio_name[2][MAX1600_GPIO_MAX] = { + { "a0vcc", "a1vcc", "a0vpp", "a1vpp" }, + { "b0vcc", "b1vcc", "b0vpp", "b1vpp" }, +}; + +int max1600_init(struct device *dev, struct max1600 **ptr, + unsigned int channel, unsigned int code) +{ + struct max1600 *m; + int chan; + int i; + + switch (channel) { + case MAX1600_CHAN_A: + chan = 0; + break; + case MAX1600_CHAN_B: + chan = 1; + break; + default: + return -EINVAL; + } + + if (code != MAX1600_CODE_LOW && code != MAX1600_CODE_HIGH) + return -EINVAL; + + m = devm_kzalloc(dev, sizeof(*m), GFP_KERNEL); + if (!m) + return -ENOMEM; + + m->dev = dev; + m->code = code; + + for (i = 0; i < MAX1600_GPIO_MAX; i++) { + const char *name; + + name = max1600_gpio_name[chan][i]; + if (i != MAX1600_GPIO_0VPP) { + m->gpio[i] = devm_gpiod_get(dev, name, GPIOD_OUT_LOW); + } else { + m->gpio[i] = devm_gpiod_get_optional(dev, name, + GPIOD_OUT_LOW); + if (!m->gpio[i]) + break; + } + if (IS_ERR(m->gpio[i])) + return PTR_ERR(m->gpio[i]); + } + + *ptr = m; + + return 0; +} +EXPORT_SYMBOL_GPL(max1600_init); + +int max1600_configure(struct max1600 *m, unsigned int vcc, unsigned int vpp) +{ + DECLARE_BITMAP(values, MAX1600_GPIO_MAX) = { 0, }; + int n = MAX1600_GPIO_0VPP; + + if (m->gpio[MAX1600_GPIO_0VPP]) { + if (vpp == 0) { + __assign_bit(MAX1600_GPIO_0VPP, values, 0); + __assign_bit(MAX1600_GPIO_1VPP, values, 0); + } else if (vpp == 120) { + __assign_bit(MAX1600_GPIO_0VPP, values, 0); + __assign_bit(MAX1600_GPIO_1VPP, values, 1); + } else if (vpp == vcc) { + __assign_bit(MAX1600_GPIO_0VPP, values, 1); + __assign_bit(MAX1600_GPIO_1VPP, values, 0); + } else { + dev_err(m->dev, "unrecognised Vpp %u.%uV\n", + vpp / 10, vpp % 10); + return -EINVAL; + } + n = MAX1600_GPIO_MAX; + } else if (vpp != vcc && vpp != 0) { + dev_err(m->dev, "no VPP control\n"); + return -EINVAL; + } + + if (vcc == 0) { + __assign_bit(MAX1600_GPIO_0VCC, values, 0); + __assign_bit(MAX1600_GPIO_1VCC, values, 0); + } else if (vcc == 33) { /* VY */ + __assign_bit(MAX1600_GPIO_0VCC, values, 1); + __assign_bit(MAX1600_GPIO_1VCC, values, 0); + } else if (vcc == 50) { /* VX */ + __assign_bit(MAX1600_GPIO_0VCC, values, 0); + __assign_bit(MAX1600_GPIO_1VCC, values, 1); + } else { + dev_err(m->dev, "unrecognised Vcc %u.%uV\n", + vcc / 10, vcc % 10); + return -EINVAL; + } + + if (m->code == MAX1600_CODE_HIGH) { + /* + * Cirrus mode appears to be the same as Intel mode, + * except the VCC pins are inverted. + */ + __change_bit(MAX1600_GPIO_0VCC, values); + __change_bit(MAX1600_GPIO_1VCC, values); + } + + return gpiod_set_array_value_cansleep(n, m->gpio, NULL, values); +} +EXPORT_SYMBOL_GPL(max1600_configure); + +MODULE_LICENSE("GPL v2"); |