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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-09 14:18:40 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-09 14:18:40 -0700 |
commit | d2d8f51e28fec278e9632cdd029facf813f579a3 (patch) | |
tree | a4580c900fe86d0db506c2ec78c247a32b0b689c /drivers/i2c/busses/i2c-aspeed.c | |
parent | ad9a19d003703ae06a6e8efc64cf26a939d9e84d (diff) | |
parent | 8ce906c13c32cfd3de71063ca4b8c3b774e4ca08 (diff) | |
download | linux-d2d8f51e28fec278e9632cdd029facf813f579a3.tar.bz2 |
Merge branch 'i2c/for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c updates from Wolfram Sang:
- new drivers for Spreadtrum I2C, Intel Cherry Trail Whiskey Cove SMBUS
- quite some driver updates
- cleanups for the i2c-mux subsystem
- some subsystem-wide constification
- further cleanup of include/linux/i2c
* 'i2c/for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (50 commits)
i2c: sprd: Fix undefined reference errors
i2c: nomadik: constify amba_id
i2c: versatile: Make i2c_algo_bit_data const
i2c: busses: make i2c_adapter_quirks const
i2c: busses: make i2c_adapter const
i2c: busses: make i2c_algorithm const
i2c: Add Spreadtrum I2C controller driver
dt-bindings: i2c: Add Spreadtrum I2C controller documentation
i2c-cht-wc: make cht_wc_i2c_adap_driver static
MAINTAINERS: Add entry for drivers/i2c/busses/i2c-cht-wc.c
i2c: aspeed: Retain delay/setup/hold values when configuring bus frequency
dt-bindings: i2c: eeprom: Document vendor to be used and deprecated ones
i2c: i801: Restore the presence state of P2SB PCI device after reading BAR
MAINTAINERS: drop entry for Blackfin I2C and Sonic's email
blackfin: merge the two TWI header files
i2c: davinci: Preserve return value of devm_clk_get
i2c: mediatek: Add i2c compatible for MediaTek MT7622
dt-bindings: i2c: Add MediaTek MT7622 i2c binding
dt-bindings: i2c: modify information formats
i2c: mux: i2c-arb-gpio-challenge: allow compiling w/o OF support
...
Diffstat (limited to 'drivers/i2c/busses/i2c-aspeed.c')
-rw-r--r-- | drivers/i2c/busses/i2c-aspeed.c | 81 |
1 files changed, 63 insertions, 18 deletions
diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c index 6fdf9231c23c..284f8670dbeb 100644 --- a/drivers/i2c/busses/i2c-aspeed.c +++ b/drivers/i2c/busses/i2c-aspeed.c @@ -53,6 +53,9 @@ #define ASPEED_I2CD_MASTER_EN BIT(0) /* 0x04 : I2CD Clock and AC Timing Control Register #1 */ +#define ASPEED_I2CD_TIME_TBUF_MASK GENMASK(31, 28) +#define ASPEED_I2CD_TIME_THDSTA_MASK GENMASK(27, 24) +#define ASPEED_I2CD_TIME_TACST_MASK GENMASK(23, 20) #define ASPEED_I2CD_TIME_SCL_HIGH_SHIFT 16 #define ASPEED_I2CD_TIME_SCL_HIGH_MASK GENMASK(19, 16) #define ASPEED_I2CD_TIME_SCL_LOW_SHIFT 12 @@ -132,6 +135,7 @@ struct aspeed_i2c_bus { /* Synchronizes I/O mem access to base. */ spinlock_t lock; struct completion cmd_complete; + u32 (*get_clk_reg_val)(u32 divisor); unsigned long parent_clk_frequency; u32 bus_frequency; /* Transaction state. */ @@ -675,7 +679,7 @@ static const struct i2c_algorithm aspeed_i2c_algo = { #endif /* CONFIG_I2C_SLAVE */ }; -static u32 aspeed_i2c_get_clk_reg_val(u32 divisor) +static u32 aspeed_i2c_get_clk_reg_val(u32 clk_high_low_max, u32 divisor) { u32 base_clk, clk_high, clk_low, tmp; @@ -695,16 +699,22 @@ static u32 aspeed_i2c_get_clk_reg_val(u32 divisor) * Thus, * SCL_freq = APB_freq / * ((1 << base_clk) * (clk_high + 1 + clk_low + 1)) - * The documentation recommends clk_high >= 8 and clk_low >= 7 when - * possible; this last constraint gives us the following solution: + * The documentation recommends clk_high >= clk_high_max / 2 and + * clk_low >= clk_low_max / 2 - 1 when possible; this last constraint + * gives us the following solution: */ - base_clk = divisor > 33 ? ilog2((divisor - 1) / 32) + 1 : 0; - tmp = divisor / (1 << base_clk); - clk_high = tmp / 2 + tmp % 2; - clk_low = tmp - clk_high; + base_clk = divisor > clk_high_low_max ? + ilog2((divisor - 1) / clk_high_low_max) + 1 : 0; + tmp = (divisor + (1 << base_clk) - 1) >> base_clk; + clk_low = tmp / 2; + clk_high = tmp - clk_low; + + if (clk_high) + clk_high--; + + if (clk_low) + clk_low--; - clk_high -= 1; - clk_low -= 1; return ((clk_high << ASPEED_I2CD_TIME_SCL_HIGH_SHIFT) & ASPEED_I2CD_TIME_SCL_HIGH_MASK) @@ -713,13 +723,35 @@ static u32 aspeed_i2c_get_clk_reg_val(u32 divisor) | (base_clk & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK); } +static u32 aspeed_i2c_24xx_get_clk_reg_val(u32 divisor) +{ + /* + * clk_high and clk_low are each 3 bits wide, so each can hold a max + * value of 8 giving a clk_high_low_max of 16. + */ + return aspeed_i2c_get_clk_reg_val(16, divisor); +} + +static u32 aspeed_i2c_25xx_get_clk_reg_val(u32 divisor) +{ + /* + * clk_high and clk_low are each 4 bits wide, so each can hold a max + * value of 16 giving a clk_high_low_max of 32. + */ + return aspeed_i2c_get_clk_reg_val(32, divisor); +} + /* precondition: bus.lock has been acquired. */ static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus) { u32 divisor, clk_reg_val; - divisor = bus->parent_clk_frequency / bus->bus_frequency; - clk_reg_val = aspeed_i2c_get_clk_reg_val(divisor); + divisor = DIV_ROUND_UP(bus->parent_clk_frequency, bus->bus_frequency); + clk_reg_val = readl(bus->base + ASPEED_I2C_AC_TIMING_REG1); + clk_reg_val &= (ASPEED_I2CD_TIME_TBUF_MASK | + ASPEED_I2CD_TIME_THDSTA_MASK | + ASPEED_I2CD_TIME_TACST_MASK); + clk_reg_val |= bus->get_clk_reg_val(divisor); writel(clk_reg_val, bus->base + ASPEED_I2C_AC_TIMING_REG1); writel(ASPEED_NO_TIMEOUT_CTRL, bus->base + ASPEED_I2C_AC_TIMING_REG2); @@ -778,8 +810,22 @@ static int aspeed_i2c_reset(struct aspeed_i2c_bus *bus) return ret; } +static const struct of_device_id aspeed_i2c_bus_of_table[] = { + { + .compatible = "aspeed,ast2400-i2c-bus", + .data = aspeed_i2c_24xx_get_clk_reg_val, + }, + { + .compatible = "aspeed,ast2500-i2c-bus", + .data = aspeed_i2c_25xx_get_clk_reg_val, + }, + { }, +}; +MODULE_DEVICE_TABLE(of, aspeed_i2c_bus_of_table); + static int aspeed_i2c_probe_bus(struct platform_device *pdev) { + const struct of_device_id *match; struct aspeed_i2c_bus *bus; struct clk *parent_clk; struct resource *res; @@ -809,6 +855,12 @@ static int aspeed_i2c_probe_bus(struct platform_device *pdev) bus->bus_frequency = 100000; } + match = of_match_node(aspeed_i2c_bus_of_table, pdev->dev.of_node); + if (!match) + bus->get_clk_reg_val = aspeed_i2c_24xx_get_clk_reg_val; + else + bus->get_clk_reg_val = match->data; + /* Initialize the I2C adapter */ spin_lock_init(&bus->lock); init_completion(&bus->cmd_complete); @@ -870,13 +922,6 @@ static int aspeed_i2c_remove_bus(struct platform_device *pdev) return 0; } -static const struct of_device_id aspeed_i2c_bus_of_table[] = { - { .compatible = "aspeed,ast2400-i2c-bus", }, - { .compatible = "aspeed,ast2500-i2c-bus", }, - { }, -}; -MODULE_DEVICE_TABLE(of, aspeed_i2c_bus_of_table); - static struct platform_driver aspeed_i2c_bus_driver = { .probe = aspeed_i2c_probe_bus, .remove = aspeed_i2c_remove_bus, |