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gpio: pca953x: Perform basic regmap conversion
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Convert the driver to use regmap to access the chips. Due to the convoluted
register mapping scheme, implement read/write/volatile check functions that
untangle the mess and perform check accordingly. This patch does not zap the
internal register cache of the PCA953x driver, nor does it push the regmap
access down into the gpiochip accessors to simplify the review. All that is
in subsequent patches.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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Marek Vasut authored and Linus Walleij committed Dec 14, 2018
1 parent b32cecb commit 4942723
Showing 1 changed file with 151 additions and 8 deletions.
159 changes: 151 additions & 8 deletions drivers/gpio/gpio-pca953x.c
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_data/pca953x.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>

Expand All @@ -30,6 +31,8 @@
#define PCA953X_INVERT 0x02
#define PCA953X_DIRECTION 0x03

#define REG_ADDR_MASK 0x3f
#define REG_ADDR_EXT 0x40
#define REG_ADDR_AI 0x80

#define PCA957X_IN 0x00
Expand Down Expand Up @@ -141,6 +144,7 @@ struct pca953x_chip {
u8 reg_output[MAX_BANK];
u8 reg_direction[MAX_BANK];
struct mutex i2c_lock;
struct regmap *regmap;

#ifdef CONFIG_GPIO_PCA953X_IRQ
struct mutex irq_lock;
Expand All @@ -164,6 +168,141 @@ static int pca953x_bank_shift(struct pca953x_chip *chip)
return fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
}

#define PCA953x_BANK_INPUT BIT(0)
#define PCA953x_BANK_OUTPUT BIT(1)
#define PCA953x_BANK_POLARITY BIT(2)
#define PCA953x_BANK_CONFIG BIT(3)

#define PCA957x_BANK_INPUT BIT(0)
#define PCA957x_BANK_POLARITY BIT(1)
#define PCA957x_BANK_BUSHOLD BIT(2)
#define PCA957x_BANK_CONFIG BIT(4)
#define PCA957x_BANK_OUTPUT BIT(5)

#define PCAL9xxx_BANK_IN_LATCH BIT(8 + 2)
#define PCAL9xxx_BANK_IRQ_MASK BIT(8 + 5)
#define PCAL9xxx_BANK_IRQ_STAT BIT(8 + 6)

/*
* We care about the following registers:
* - Standard set, below 0x40, each port can be replicated up to 8 times
* - PCA953x standard
* Input port 0x00 + 0 * bank_size R
* Output port 0x00 + 1 * bank_size RW
* Polarity Inversion port 0x00 + 2 * bank_size RW
* Configuration port 0x00 + 3 * bank_size RW
* - PCA957x with mixed up registers
* Input port 0x00 + 0 * bank_size R
* Polarity Inversion port 0x00 + 1 * bank_size RW
* Bus hold port 0x00 + 2 * bank_size RW
* Configuration port 0x00 + 4 * bank_size RW
* Output port 0x00 + 5 * bank_size RW
*
* - Extended set, above 0x40, often chip specific.
* - PCAL6524/PCAL9555A with custom PCAL IRQ handling:
* Input latch register 0x40 + 2 * bank_size RW
* Interrupt mask register 0x40 + 5 * bank_size RW
* Interrupt status register 0x40 + 6 * bank_size R
*
* - Registers with bit 0x80 set, the AI bit
* The bit is cleared and the registers fall into one of the
* categories above.
*/

static bool pca953x_check_register(struct pca953x_chip *chip, unsigned int reg,
u32 checkbank)
{
int bank_shift = pca953x_bank_shift(chip);
int bank = (reg & REG_ADDR_MASK) >> bank_shift;
int offset = reg & (BIT(bank_shift) - 1);

/* Special PCAL extended register check. */
if (reg & REG_ADDR_EXT) {
if (!(chip->driver_data & PCA_PCAL))
return false;
bank += 8;
}

/* Register is not in the matching bank. */
if (!(BIT(bank) & checkbank))
return false;

/* Register is not within allowed range of bank. */
if (offset >= NBANK(chip))
return false;

return true;
}

static bool pca953x_readable_register(struct device *dev, unsigned int reg)
{
struct pca953x_chip *chip = dev_get_drvdata(dev);
u32 bank;

if (PCA_CHIP_TYPE(chip->driver_data) == PCA953X_TYPE) {
bank = PCA953x_BANK_INPUT | PCA953x_BANK_OUTPUT |
PCA953x_BANK_POLARITY | PCA953x_BANK_CONFIG;
} else {
bank = PCA957x_BANK_INPUT | PCA957x_BANK_OUTPUT |
PCA957x_BANK_POLARITY | PCA957x_BANK_CONFIG |
PCA957x_BANK_BUSHOLD;
}

if (chip->driver_data & PCA_PCAL) {
bank |= PCAL9xxx_BANK_IN_LATCH | PCAL9xxx_BANK_IRQ_MASK |
PCAL9xxx_BANK_IRQ_STAT;
}

return pca953x_check_register(chip, reg, bank);
}

static bool pca953x_writeable_register(struct device *dev, unsigned int reg)
{
struct pca953x_chip *chip = dev_get_drvdata(dev);
u32 bank;

if (PCA_CHIP_TYPE(chip->driver_data) == PCA953X_TYPE) {
bank = PCA953x_BANK_OUTPUT | PCA953x_BANK_POLARITY |
PCA953x_BANK_CONFIG;
} else {
bank = PCA957x_BANK_OUTPUT | PCA957x_BANK_POLARITY |
PCA957x_BANK_CONFIG | PCA957x_BANK_BUSHOLD;
}

if (chip->driver_data & PCA_PCAL)
bank |= PCAL9xxx_BANK_IN_LATCH | PCAL9xxx_BANK_IRQ_MASK;

return pca953x_check_register(chip, reg, bank);
}

static bool pca953x_volatile_register(struct device *dev, unsigned int reg)
{
struct pca953x_chip *chip = dev_get_drvdata(dev);
u32 bank;

if (PCA_CHIP_TYPE(chip->driver_data) == PCA953X_TYPE)
bank = PCA953x_BANK_INPUT;
else
bank = PCA957x_BANK_INPUT;

if (chip->driver_data & PCA_PCAL)
bank |= PCAL9xxx_BANK_IRQ_STAT;

return pca953x_check_register(chip, reg, bank);
}

const struct regmap_config pca953x_i2c_regmap = {
.reg_bits = 8,
.val_bits = 8,

.readable_reg = pca953x_readable_register,
.writeable_reg = pca953x_writeable_register,
.volatile_reg = pca953x_volatile_register,

.cache_type = REGCACHE_RBTREE,
.max_register = 0x7f,
};

static u8 pca953x_recalc_addr(struct pca953x_chip *chip, int reg, int off,
bool write, bool addrinc)
{
Expand Down Expand Up @@ -193,8 +332,7 @@ static int pca953x_read_single(struct pca953x_chip *chip, int reg, u32 *val,
u8 regaddr = pca953x_recalc_addr(chip, reg, off, false, false);
int ret;

ret = i2c_smbus_read_byte_data(chip->client, regaddr);
*val = ret;
ret = regmap_read(chip->regmap, regaddr, val);
if (ret < 0) {
dev_err(&chip->client->dev, "failed reading register\n");
return ret;
Expand All @@ -209,7 +347,7 @@ static int pca953x_write_single(struct pca953x_chip *chip, int reg, u32 val,
u8 regaddr = pca953x_recalc_addr(chip, reg, off, true, false);
int ret;

ret = i2c_smbus_write_byte_data(chip->client, regaddr, val);
ret = regmap_write(chip->regmap, regaddr, val);
if (ret < 0) {
dev_err(&chip->client->dev, "failed writing register\n");
return ret;
Expand All @@ -223,8 +361,7 @@ static int pca953x_write_regs(struct pca953x_chip *chip, int reg, u8 *val)
u8 regaddr = pca953x_recalc_addr(chip, reg, 0, true, true);
int ret;

ret = i2c_smbus_write_i2c_block_data(chip->client, regaddr,
NBANK(chip), val);
ret = regmap_bulk_write(chip->regmap, regaddr, val, NBANK(chip));
if (ret < 0) {
dev_err(&chip->client->dev, "failed writing register\n");
return ret;
Expand All @@ -238,8 +375,7 @@ static int pca953x_read_regs(struct pca953x_chip *chip, int reg, u8 *val)
u8 regaddr = pca953x_recalc_addr(chip, reg, 0, false, true);
int ret;

ret = i2c_smbus_read_i2c_block_data(chip->client, regaddr,
NBANK(chip), val);
ret = regmap_bulk_read(chip->regmap, regaddr, val, NBANK(chip));
if (ret < 0) {
dev_err(&chip->client->dev, "failed reading register\n");
return ret;
Expand Down Expand Up @@ -793,6 +929,14 @@ static int pca953x_probe(struct i2c_client *client,
}
}

i2c_set_clientdata(client, chip);

chip->regmap = devm_regmap_init_i2c(client, &pca953x_i2c_regmap);
if (IS_ERR(chip->regmap)) {
ret = PTR_ERR(chip->regmap);
goto err_exit;
}

mutex_init(&chip->i2c_lock);
/*
* In case we have an i2c-mux controlled by a GPIO provided by an
Expand Down Expand Up @@ -843,7 +987,6 @@ static int pca953x_probe(struct i2c_client *client,
dev_warn(&client->dev, "setup failed, %d\n", ret);
}

i2c_set_clientdata(client, chip);
return 0;

err_exit:
Expand Down

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